Todd Bookwalter A.E. Senior Thesis Summary Book Spring Table of Contents. Building Design & Systems Summary Local Conditions..

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3 Table of Contents Thesis Abstract. i Table of Contents ii iii Credits & Acknowledgements.... iv Executive Summary.... v Thesis Report Introduction... 1 Project Introduction & Background Information Building Design & Systems Summary Local Conditions.. 6 Client Information Contractual Arrangements Staffing Plan Project Cost Evaluation Detailed Project Schedule Site Layout Plans Thesis Research & Analyses Alternate Formwork System Evaluation Executive Summary. 16 Research & Analysis Introduction Available Formwork Systems Slab Design Factors Formwork System Selection Cost & Production Factors Conclusion ii

4 Table of Contents (Continued) The Green Building Reference Guide Executive Summary. 30 Research & Analysis Introduction. 31 Sustainable & LEED Construction Survey Reference Guide Development Reference Guide Utilization Initial User Feedback Conclusion Structural Redesign of Office Tower Executive Summary. 41 Research & Analysis Introduction Concrete Structure Design Development Concrete Structure Analysis Budget & Schedule Comparison Structural & M.E.P. Coordination Applications of Alternate Formwork System Environmental Impact: Concrete vs. Steel Conclusion References Appendices Appendix A: Project Introduction & Background Information Appendix B: Alternate Formwork System Evaluation Appendix C: The Green Building Reference Guide Appendix D: Structural Redesign of Office Tower iii

5 Credits & Acknowledgements I would like to thank the following people for their immense help and support in the development of this Senior Thesis Project: Penn State University Dr. Michael Horman Dr. David Riley Dr. Kevin Parfitt James G. Davis Construction Corporation Bill Moyer Dave Purdy Hasan Alsayegh Kim Pexton The Keech Company Bill Keech Sr. Bill Keech Jr. Southland Concrete Mark Aulabaugh Titan Formwork Systems, LLC Paul Tauscher Arlington County, Virginia Michael Lewis Personal Contacts My fiancé, Diane, for being my best friend My family, for their support and guidance My friends iv

6 A.E. Senior Thesis Summary Book Executive Summary This thesis summary book details the extensive investigations and analyses performed on the Navy League Building, located in. The book is divided into three main sections: Project Introduction & Background Information, Thesis Research and Analyses, and finally, the Appendix. Upon completion, the Navy League Building will be Arlington s first LEED rated office building. To gain a better understating of this challenging project, a variety of technical investigations were performed. The project delivery system was analyzed, system estimates were developed, and other planning and scheduling issues were addressed to provide a basis for further research and analyses. The first thesis research topic is an evaluation of alternate formwork systems for the building s underground parking garage. The current handset aluminum formwork system used is a labor and material intensive process. Criteria such as engineering of the system, material costs, labor, local building codes, and reusability were used to determine if an alternate system could have a positive impact on the budget and sustainability aspects of the concrete formwork. The second research topic resulted in the development of The Green Building Reference Guide. The GBRG is a website created to address the issues and requirements associated with green building projects. It was designed to assist construction professionals by organizing resources and information pertinent to a sustainable / LEED rated project s management and successful completion. Initial trials of the website by industry professionals were also used to acquire feedback and improve the utility of the resource. The final thesis research topic analyzed the viability of a cast in place concrete structural system for the building s office tower. Maintaining the layout of the current steel frame, a post-tensioned flat slab design was developed and compared in terms of cost, schedule, coordination, and sustainability issues. v

7 Thesis Report Introduction This Senior Thesis report summarizes the research and analyses conducted for the year-long Architectural Engineering Capstone Project. The report is based off of s first LEED rated office building, the Navy League Building. The report begins by providing background information on the project and its execution. The project delivery system is analyzed, including contractual arrangements, a staffing plan, a construction schedule, and site plans among other items. The goals of the building s owner are addressed and estimates were also performed to gain an indepth understanding of the project. Given the background information, the second section of the report outlines the investigation of potential improvement topics for the project. Overall, analysis topics were selected to improve both the quality and value of the project while maintaining the building s theme of green construction and sustainability. The first thesis research topic is an evaluation of alternate formwork systems for the building s underground parking garage. Criteria such as engineering of the system, material costs, labor, local building codes, and reusability are used to determine if an alternate system could have a positive impact on the budget and sustainability aspects of the concrete formwork. The second research topic resulted in the development of The Green Building Reference Guide. In general, the GBRG is a website created to address the issues and requirements associated with green building projects. It is designed to assist construction professionals by organizing resources and information pertinent to a sustainable / LEED rated project s management and successful completion. The final thesis research topic analyzes the viability of a cast in place concrete structural system for the building s office tower. The underlying notion is that C.I.P. concrete used for the entire structure may be more efficient and provide value through cost and schedule reductions. To test the hypothesis, a post-tensioned flat slab design was developed and compared to the original steel structure in terms of cost, schedule, coordination, and sustainability issues. The last section of the report consists of an appendix for the background information and thesis research topics. The appendix provides additional calculations, summary data, and drawings not included in the body of the main report. 1

8 Project Introduction & Background Information 2

9 Architecture Building Design & Systems Summary utilizes both formal and informal design elements. Conforming to the site, the building plan is skewed, with non-perpendicular corners on the North side setting an informal tone. The building also steps back as it rises, creating terraces for tenant office spaces. Formality is achieved by the seven-story tower, with its architectural precast and fenestration designed in a vertical theme. At the top center of the tower, a circular metal-clad screenwall completes the structure. The most notable feature of the Navy League Building is that it will be Arlington's first green building, receiving a Silver LEED rating. One of the key functional components related to the green design is that a sand filter vault and water retention tank filter and store stormwater for later building use, such as irrigation. Another functional component is the sub-grade parking garage with available bike racks, car charging stations, and vehicle capacity of 358. Inside, the first floor features a two-story lobby and grand staircase. Polished stone and satin brass finishes are found throughout the area. The remainder of the first floor accommodates meeting rooms and spaces for restaurants and retail shops. The second floor will house the headquarters of The Navy League, while the remaining floors will be leased to other tenants. Demolition Before excavation for could proceed, the existing structures on site had to first be removed. The existing structures included a 3-story office building (The Navy League s original headquarters), a strip of row houses, and two surface parking lots. The adjacent photograph shows an aerial view of the site prior to demolition. The results of a hazardous material survey indicated that the existing buildings contained asbestos, mainly in the form of floor tile. Due to these conditions, asbestos abatement was required prior to any demolition activities. Once demolition was underway, National Wrecking, the demolition and earthwork contractor, was required to recycle 75% of the materials (such as pulverized concrete) in order to meet the project s LEED requirements. Outline of Building Perimeter 3

10 Structural Steel Frame Building Design & Systems Summary (Continued) A steel skeleton and composite deck comprise the structural system of the 7- story tower. W-sections for beams, girders, and columns are specified as ASTM A-572 Grade 50 or ASTM 992 Grade 50 steel. The connections are typically bolted, however, some welded, full moment connections are also included. Lateral bracing is specified near openings for elevator shafts and stairwells. For the composite deck, 3-1/4 lightweight concrete and 2, 18 gage deck works in combination with 6x6 W.W.F. and welded shear studs. To expedite the placement of concrete for the 4-level sub-grade parking deck, two (2) horizontal jib type tower cranes were used. The cranes were located near the Northeastern and Northwestern corners of the site. After the garage was complete, one tower crane was dismantled, with the crane in the Northeastern corner remaining to erect half of the steel frame. This crane has a boom length of approximately 100 and a lifting capacity of at least 6,000 lbs. at the tip (as the heaviest pick weighs 5,800 lbs.). A mobile crane will be used to place the remainder of the frame. Cast in Place Concrete Concrete for the parking garage was obtained from a local supplier and delivered by trucks. The concrete was then placed via a crane and bucket operation. Formwork types included pre-manufactured metal forms as well as stick-built forms. Columns and perimeter walls were typically formed with metal forms. To form the horizontal slabs, plywood was placed over aluminum shores. Precast Concrete The acid-washed architectural precast panels, composing the majority of the façade, are to be fabricated in Oxford, North Carolina and trucked to the site. The PCI (Precast / Prestressed Concrete Institute) certified manufacturer will hire an erector to install the panels via a mobile crane. The panels will be attached to the frame via brackets on the steel members and imbeds in the panels. Mechanical System Room Locations: (1) in the core of the B-1 (garage) level (2) on the L-1 level (lobby) 4

11 Building Design & Systems Summary (Continued) (2) per floor for levels 2 7 of the tower The remaining mechanical systems are located in the penthouse. System & Distribution Types: Parking Garage: o 16,850CFM garage supply fans & 11,500CFM exhaust fans o Fan coil units for the elevator lobbies on the parking garage o Stair & elevator pressurization fans Levels 2-7: AHU s connected to VAV boxes with integral heaters Penthouse: o (3) cooling towers o (2) centrifugal water chillers Fire Suppression: Wet-pipe automatic sprinkler system for the office tower Dry-pipe automatic sprinkler system for garage levels Electrical System (1) 4000A, 480V utility transformer for building systems (1) 1600A, 480V utility transformer for retail power (2) 4000A, 3 phase, 480Y/277V 4-wire switchboards (2) 3,000A copper bus duct power risers for tower 400KW/500KVA diesel generator connected to (2) 400A automatic transfer switches Masonry There is only minor use of masonry components in the structure. The garage level contains CMU walls for equipment rooms and ventilation shafts. Curtain Wall The curtain wall and glazing system consists of aluminum mullions with tinted glass vision panels and opaque spandrel panels. For the majority of the façade, window units are set into the precast panels. The design of the system s components and connection details are the responsibility of the installer/manufacturer. 5

12 Support of Excavation Building Design & Systems Summary (Continued) The site excavation is supported by a system of steel soldier piles and wood lagging. In addition to this, steel rakers are used along the Clarendon Boulevard side, which runs parallel to a WMATA tunnel. This system was installed to insure minimal disturbance to the tunnel and it s ventilation shafts. Due to unfavorable soil conditions, site dewatering was a challenge. Two (2) 50 deep wells were drilled so that water could be removed with sump pumps. A well point system consisting of forty (40) 20 deep wells was later installed to remove water and provide suitable conditions for excavation. To provide permanent site dewatering, drainage board on the exterior garage walls channel water to drain tile circling the building s perimeter. The drain tile sends water to a sump pit for removal by a float-activated pump. Preferred Construction Methods Local Conditions As observed from recent projects in the area, Arlington Virginia does not appear to have a single preferred method of construction. In terms of structural systems, both cast in place and structural steel frames have been used for recently constructed buildings. It is the general assumption that local construction methods are selected based on the current market conditions and/or the building s design criteria. For example, across the river, in downtown Washington D.C., most buildings use posttensioned concrete frames. Considering the local height restrictions, this method provides the most efficient use of the building s volume (thinner slabs = more floors, or more floor-to-floor height). Since Arlington does not have the same restrictions, a variety of construction methods have flourished in the area. Recycling Fees By recycling materials typically discarded as waste, cost savings can be achieved. This is of benefit to the project, considering that the Navy League Building must abide by LEED standards to achieve a Silver rating. To understand the savings, consider that the average cost to remove a standard construction waste dumpster is approximately $600. Comparatively, a dumpster of recyclable materials only costs approximately $400. The lower cost results from the scrap values of the materials. 6

13 Client Information The Navy League is unique among military-oriented associations in that it is a civilian organization dedicated to the education of our citizens, including our elected officials, and the support of the men and women of the sea services and their families *. Founded in 1902, the United States Navy League s mission includes educating the American people about the role of sea power in the nuclear age, and fostering an interest in the Navy, Marine Corps, Coast Guard, and Merchant Marines. As the Navy League was outgrowing its original facilities, it was determined that a new headquarters should be built on the same site. Replacing the old building will be a 7 story office tower and 4 level parking garage. Since The Navy League will only occupy the second floor, the remaining floors can be leased out to other tenants. The mixed-use building can also house retail shops and restaurants on the ground floor. With prime real estate and parking at a premium in downtown Arlington, the new 2300 Wilson Boulevard building will be a sound investment for The Navy League. The Navy League selected Davis Construction as the general contractor because cost and schedule are of great importance. Illustrating the issue of cost is that The Navy League contracted Davis to complete the building for a gross maximum price. Schedule is even more important. Because The Navy League s existing facilities were demolished for the new building, they are temporarily renting office space. As rent is paid on a monthly basis, any delays to the building s completion may force them to pay an extra month s rent, or possibly more. Considering the issues of cost and schedule, the keys to owner satisfaction become evident. To achieve the cost and schedule goals, changes or problems that occur during construction must be dealt with in a timely and efficient manner. Furthermore, the contractors on the project must be willing and able to accelerate construction if delays occur. Achieving the goals in this manner will contribute to the overall satisfaction of the owner. * 7

14 Contractual Arrangements The Navy League Project is being delivered under a traditional design-bid-built system. As part of this process, proposals were received from three different general contractors to work with the project development team as part of the pre-construction design phase. James G. Davis Construction was selected based on a prior relationship with the owner s representative (The Keech Company), Davis reputation in the marketplace, the reputation of the pre-construction manager, and Davis commitment to value engineering during the pre-construction phase. For the next part of the process, budgets were requested from the three different contractors at the completion of the schematic design, design development, and permit drawings phases. Davis budget was the lowest of the three for each stage. Considering Davis budget and reputation, The Navy League decided to pursue a negotiated GMP contract with Davis Construction. To better understand the contractual arrangements, a diagram was created. As seen on page 10, The Navy League holds separate contracts with all major project team members. On the design and engineering side, fee-based contracts are held with the Owner. The Architect s contract is one exception to this arrangement in that it also includes the Structural and M.E.P. engineer s contract. Although specific information was not provided, it was assumed that all design and engineering contracts were fixed fee as opposed to cost plus fee. For the construction agreements, the Navy League holds a Guaranteed Maximum Price contract with Davis Construction. In turn, Davis then holds separate lump sum contracts with the various subcontractors. The contract held between DAVIS and the Navy League is based off the standard AIA A111 Form of Agreement Between Owner and Contractor, 1987 edition. This document was modified, with specific alterations made to the schedule, damages, and GMP sections. One requirement of the contract is that the Contractor shall achieve Substantial Completion of the entire Work not later than 620 calendar days after the date of commencement. If the Contractor cannot meet this deadline, liquidated damages will be assessed. The damage amounts are specified as $2,000 per calendar day for a delay of 1 to 30 calendar days, and $7,500 per day for any delays over 30 calendar days. Procedures for excess costs and cost savings are also specified under the modifications to the contract. In the event that the actual construction costs incurred by the contractor exceed the GMP, the Contractor must pay the excess. If actual costs are less than the GMP, the Owner is entitled up to the first $500,000 of this amount. Any savings above that amount will be divided into 55% for the Owner, 5% for the Architect, and 40% for the Contractor. Another key part of the contractual agreements are bonds and insurance. Using AIA Document A201, these conditions are specified in Davis contract with the Navy 8

15 Contractual Arrangements (Continued) League. For insurance purposes, Davis must have Contractor s Liability Insurance, including Worker s Compensation, as well as automobile insurance for all vehicles used by the Contractor on site. It is the responsibility of the Owner to provide Builder s Risk, General Liability, and Property Insurance. Bonds are also necessary for both the General Contractor as well as all major subcontractors. It is the responsibility of Davis to purchase a payment and performance (P%P) bond. In turn, Davis purchases P&P bonds for all its major subcontracts such as concrete, steel, precast, etc. Davis will also purchase P&P bonds for any subcontracts deemed to be of high risk. Considering these details of the project delivery system, one can assess its appropriateness. In general, it seems that the design-bid-build approach has been working, however there may be room for improvement. One suggestion is to eliminate the consultant Architect and one of the Owner s representatives. The current system s duality does not appear to be necessary as it can increase Owner costs and decrease communication efficiency. A possible alternative to help eliminate these difficulties would be a design-build delivery system. 9

16 Contractual Arrangements (Continued) Project Delivery System Flowchart Owner The United States Navy League Contact: Stephen Pietropaoli Owner s Representative The Keech Company, L.C. Contact: Bill Keech Sr. General Contractor James G. Davis Construction Corp. Contact: David Purdy Concrete Southland Concrete Contact: Mark Aulabaugh Mechanical/Plumbing W.E. Bowers Contact: Monte Richardson Earthwork National Wrecking Corp. Contact: Bill Finagin, Jr. Electrical J.E. Richards Contact: Mike Lambert Owner s Representative (Secondary) Lincoln Properties Contact: Donald Bowers Architect Page Southerland Page, LLP Contact: Jeff Maxwell Structural Engineer ReStl Designers, Inc. Contact: George Wang M.E.P. Engineer E.K. Fox & Associates, Ltd. Fire Protection Fireguard Corp. Contact: Don Brown Structural Steel Strait Steel Contact: Bill Calhoun Civil Engineer VIKA Incorporated Architectural Precast Gate Concrete Contact: David Greer Glass & Glazing Service Glass Industries, Inc. Elevators Fujitec America, Inc. Contact: Kathy Van Houten Stone Janeiro, Inc. Contact: Michael Lizarraga Architect (Consultant) MTFA Architecture, Inc. Contact: Meagan Jancy Contract Type Key = Lump Sum Contract = Fee Based Contract (fixed fee) = GMP Contract 10

17 Staffing Plan The project staff overseeing construction of is visually represented in the diagram below. The team oriented organizational structure used by Davis Construction consists of project management staff and field staff. Responsibilities of the field staff, particularly the superintendent, are explicitly outlined in the contract requirements. As stated under the general conditions portion of the contract, The Contractor shall employ a competent superintendent and necessary assistants. Furthermore, the superintendent shall represent the contractor, and communications given to the superintendent shall be as binding as if given to the Contractor. To fill this role, there are two field superintendents working in tandem. Considering the role of the superintendents, it is imperative to have open lines of communication between the field and the office. The main office in Rockville, MD is where the project managers are based, but they are generally on site at least one day per week. This arrangement is typical for Davis, offering the project managers a higher degree of logistical and administrative support. Once the initial stages of construction are complete, the project manager and assistant project manager may work on site until project completion to expedite the communication and decision processes. Both the project managers and superintendents work full-time throughout the duration of the project with some additional time required beyond substantial completion. These durations are given in the General Contractor Staff Durations Table. Other key staff, apart from the project managers and superintendents, are the field engineers and the project coordinator. The project coordinator helps insure that documents and drawings are properly coordinated and processed for field use. Similarly, the field engineers insure the proper layout and placement of building components with respect to the drawings. These two roles are essential for minimizing delays and maintaining quality during construction. The overall effectiveness of the staff structure will become apparent as the project progresses. At its current stage, it appears that more support staff for the project managers and field personnel would be beneficial in decreasing workloads. The increased staff could help process documents (such as submittals, meeting minutes, etc.) and leave more difficult tasks for experienced members of the team. 11

18 Staffing Plan (Continued) General Contractor Organizational Structure Office Project Executive Barry Perkins Field Project Manager David Purdy Senior Superintendent Doug Bauer Assistant Project Manager Hasan Alsayegh Project Coordinator Andrea Copeland Project Administrator Lori Wyatt Assistant Superintendent Robert Duke Nick Field Engineer Mike O Neil Assistant Field Engineer Rudy Pena Project Cost Evaluation R.S. Means Estimate As seen by comparing the tables below, the estimated Means cost may be in the ballpark, but is still not an accurate measure of the actual building costs. The actual building cost was $24,275,702, or approximately $64.31 per square foot. To obtain the estimate, cost data was taken both from a model 5-10 story office building and an underground parking garage (since the Navy League Building has both components). After applying the appropriate adjustment factors, a total cost of $25,196,395 was found. The most likely source of the discrepancy is from the model 5-10 story office. The Means cost basis for that type of building includes interior finishes throughout. Since the Navy League Building was priced as a base building, it only includes the finishes for the lobby and the building core. Although the Means data is not entirely reliable, it proves its worth in providing a rough building cost estimate. 12

19 Project Cost Evaluation (Continued) Description Construction Cost (less sitework, general conditions, and fee) Building Cost (with general conditions and fee) Actual Costs Cost Cost / Square Foot *Note: includes parking garage; total building area = 377,508 ft 2 $20,635,000 $54.66 $24,275,702 $64.31 Total Building Cost $27,600,000 $73.11 Structural System $1,671,100 $4.43 Concrete (cast in place and architectural) $6,873,082 $18.20 Mechanical $3,871,463 $10.26 Description Office Building Parking Garage Electrical $1,722,673 $4.56 Design Cost Withheld for confidentiality reasons S.F. Area (ft 2 ) 212,947 R.S. Means Square Foot Estimated Costs S.F. Cost Perimeter Story * Perimeter L.F. Hgt. Interpolated Add/Deduct Add/Deduct from Means data 725 (averaged) Adjusted S.F. Cost Total Cost $ $ $1.94 $93.89 $19,993, , $ $1.32 $48.63 $8,002,690 **Data obtained from R.S. Means 2004 Square Foot Costs: Section M.470 Office 5-10 Story Section M.280 Garage, Underground Parking Adjusted with 0.9 location factor Final Building Cost: $25,196,395 Detailed Systems Estimate Using R.S. Means 2004 Assemblies Cost Data Book, a detailed estimate was performed for the building s superstructure. This estimate included the structural steel members, metal deck installation, and concrete placement and finishing for the 7-story office tower. Once the quantities and prices were determined for each component, they were compiled into spreadsheets. Using the detailed spreadsheets, a summary cost 13

20 Project Cost Evaluation (Continued) table was compiled for the superstructure (located in Appendix A). Note that the total cost was adjusted by the location factor (89.4% for ) to arrive at a total superstructure cost and cost per square foot of building area. Detailed Project Schedule A detailed schedule of construction activities for the Navy League Building is located in Appendix A. Site Layout Plans Site layout plans for the excavation & concrete phase as well as the superstructure phase are located in Appendix A. As illustrated in the attached plans, space is at a premium on The Navy League Building site. With the available perimeter square footage used for material storage and staging, the majority of employee parking must be accommodated off-site. Deliveries are typically handled along North Wayne Street, while concrete trucks can be unloaded on both the east and west sides. This arrangement keeps the trucks off the busy streets and provides access to the tower cranes. There are two tower cranes used for the concrete operation. The one near the Northwestern corner is shorter than the other and will be removed upon completion of the garage. Office trailers are located on the western side, allowing a clear view of the entire area. Once the garage and ground floor slab are complete, more storage and maneuverability will be available. One related benefit is that the parking garage will be available for employee parking. This will eliminate the expense of providing off-site parking. An essential element of the site plan are the provisions for employee and pedestrian safety. There are two fences, one around the entire site, and another encircling the excavation. Along Wilson Boulevard, Jersey barriers provide a lane for pedestrian traffic. Flagmen are also used to direct traffic when deliveries or equipment are in the streets. These measures combine to help reduce the risk of incidents. 14

21 Thesis Research & Analyses This section includes: Alternate Formwork System Evaluation The Green Building Reference Guide Structural Redesign of Office Tower 15

22 Alternate Formwork System Evaluation Executive Summary The current handset aluminum formwork system used in the Navy League Building s parking garage is a labor and material (plywood) intensive process. To determine a possible alternate, a variety of pre-manufactured systems were analyzed. The overall goal of this research was to determine if an alternate system could have a positive impact on the budget and sustainability aspects of the concrete formwork. Criteria such as engineering of the system, material costs, labor, local building codes, and reusability were used to determine an alternate. After selecting the Titan HV system, a budget was compiled to judge both systems. With the handset aluminum system providing cost savings and equal environmental impact as the Titan HV, it was concluded to be the most appropriate system for the Navy League Building s parking garage. Although the analysis did not find pre-manufactured formwork to be more beneficial, it reinforced that the standard handset aluminum system is the best choice for Navy League. 16

23 Research & Analysis Introduction Overview: Determining the best methods of building construction is a challenging aspect on any project. Considering this, the selection of the most appropriate formwork system is necessary for concrete installation. While many different systems may work, a system which is quickly and easily erected can provide benefits to the budget and sustainability aspects of a LEED rated project. In the case of the Navy League building, the viability of a pre-manufactured system for elevated slab placement will be analyzed. Focusing on the sub-grade garage slabs, the alternate system will be compared to the handset aluminum system actually used on site. The current system is a labor and material (plywood) intensive, process. To address these issues, the potential benefits of a pre-manufactured system are compared to benefits of the system as-built. Analysis Outline: The basic steps used to analyze the formwork systems are outlined below: Gathered detailed erection and production data on the current formwork system (from general contractor and concrete subcontractor) Researched pre-manufactured gang form systems Determined viability of possible alternates and selected appropriate system based on erection, material availability, and structural stability requirements Prepared budget for alternate system Compared alternate budget to original and selected system with greater cost / benefit ratio Goal: The overall goal of this research is to determine if an alternate system could have a positive impact on the budget and sustainability aspects of the concrete formwork. As cast in place concrete placement is one of the most expensive activities on the project, an alternate formwork system has the potential to reduce costs. A pre-manufactured system featuring reusable components would also reinforce the sustainable theme of the building. 17

24 Research & Analysis Introduction (continued) Images of the current handset aluminum formwork system 18

25 Available Formwork Systems The formwork systems listed below are currently available for rental or purchase through formwork distributors. These systems were examined in terms of their applicability for use in s parking garage. A basic overview, list of advantages, and product images are provided for each different system. Mid-State Filigree Systems ( The Filigree system uses a combination of factory precast and an on-site cast in place topping to produce elevated slabs. Thin precast panels and trays containing the lower slab reinforcing are set in place on top of standard shoring. After installing further reinforcement and polystyrene foam void blocks, concrete is poured into the precast pieces, thus completing the slab. As listed on the manufacturer s website, advantages of the Filigree system include labor and time savings, as well as the claim that it is environmentally friendly. Although not specifically stated by the manufacturer, it is assumed that the time and labor savings are most easily achieved on a high-rise project using crews trained in the Filigree system s construction. Labor Savings: The prefabrication technology in Filigree reduces the need for field skilled and unskilled trades. Although all trades are represented, fewer are needed for each task with a reduction in payroll needs and enhanced cash flow. Time Savings: Filigree structures go up fast. High production rates of up to 50,000 sq.ft. per 5 day week can be achieved. Environmentally Friendly: Many trees are saved by the elimination of wood and plywood framing. Image of a Filigree beam & slab system 19

26 Available Formwork Systems (continued) Peri Skydeck Formwork System ( This modular system from Peri features aluminum-framed panels with integral faced plywood. Props fitted with special dropheads allow the panels to be removed while the props remain in place to act as reshores. According to the manufacturer, advantages of the Skydeck system include: Lightweight o The slab panels featuring the integral aluminum frame and plywood sheathing do not weigh more than 35 lbs. each Early striking o The dropheads on the props allow the slab panels to be removed and reused while the prop remains to support the curing concrete. Low maintenance o The props feature self-draining edges and a powder coated finish Release of panel Drophead 20

27 Available Formwork Systems (continued) Tabla by Gillespie Practical Technologies, Inc. ( The Tabla formwork system is comparable to Skydeck in terms of its components and operation. Aluminum-framed panels sheathed with plastic plywood rest on props with an integral drophead. After the slab is poured, the panels can be released and swung down to be removed. The posts remain as reshores. According to the manufacturer, some advantages of the Tabla system include: Fast erection & removal o 250 sq.ft. can be erected per man-hour and 400 sq.ft. can be dismantled per man-hour. Reusable o The deck panels are sheathed with plastic plywood which has a claim of 200 to 250 uses. Custom Details o The system has components which can accommodate many custom slab details such as beams and cantilever sections. Panel sections Drophead 21

28 Available Formwork Systems (continued) Titan HV Formwork System ( The Titan system is similar to both the Tabla and Skydeck systems in terms of operation and components. The formwork uses main and secondary aluminum beam sections, a reusable drophead, and plywood sheathing. After the slab is poured, the beams sections can be released by hitting a lever. As with the other systems, the posts remain to act as reshores. Some advantages of the Titan HV system include: Safe erection process o The post shores and beam sections can be assembled on the ground, making for a more safe and comfortable work environment. Custom-framed openings o The main beams of the system are designed to allow wood 4x4s in place of the secondary beams. The wood beams can be used to frame unusual slab designs and filler conditions. Quick-release dropheads o The dropheads of the system feature a quick-release mechanism allowing release via a single hammer stroke. Drophead System assembly 22

29 Slab Design Factors Determining which formwork systems adequately accommodate the structure s design is an initial step in the selection process. There are a variety of available systems that cater to specific slab designs. Considering this, inappropriate prefabricated systems should not be forced into use because of their cost or potential schedule and labor savings. As seen in the plan below, s garage is a two-way flat slab with average bay sizes between 20 x 30 and 30 x 30. The slab thickness varies from 8 12 and the average floor to floor height is approximately 9. The irregularshaped polygon outline of the building creates a challenge to formwork installation. If a pre-manufactured system is to be used, it must be adaptable to accommodate the angled slab edges. This characteristic, and other factors such as the slab s multiple elevation changes may limit the possible production efficiencies of the systems described in the previous section. First Floor Slab Framing Plan The parallelogram shape and multiple slab elevation changes pose a design challenge to standardized formwork systems 23

30 Slab Design Factors (Continued) First Floor Slab Detail The detail provided above of the garage s southwest corner show the angled exterior walls and slab elevation changes two elements which can slow formwork construction. Garage Slab Design Characteristics Slab Design Type Two-way flat slab Design Load 50 psf Concrete Strength 5,000 psi Slab Thickness 8 12 Floor to Floor Height 9-4 Average Column Size 2-0 x 2-0 Number of Levels (of elevated slab) 4 Area of Garage Elevated Slab 119,685 Sq. Ft. 24

31 Formwork System Selection There are many factors which must be considered to determine the most appropriate formwork system for. These factors include, but are not limited to, the design characteristics of the system itself, engineering of the system, material costs, labor, local building codes, and reusability. Design Characteristics To begin, the critical factor in selecting an alternate formwork system for the Navy League Building is its adaptability to the current structure s design. The parking garage is what is known as a cut-up design the basic outline of the structure is an irregular polygon while the slab itself features a variety of beam sizes and drop panels. The concrete subcontractor chose a standard system due to these irregularities. Use of standard metal formwork is also supported by the Interactive Horizontal Formwork Selection System by Hanna and Sanvido. This document confirms that a standard metal system is the most appropriate under the given conditions. However, it must be noted that many of the formwork systems described above were not yet available after the document was published. Considering that a pre-manufactured formwork system must be selected to suit the Navy League s structure, and not vice versa, the Filigree system can be eliminated as it does not correspond to the slab design. The garage was engineered as a cast in place two-way flat slab. The Filigree s combination of precast and cast in place components in addition to the foam void blocks would require a redesign of the slab and corresponding reinforcement. Despite the Filigree system s incompatibility, the remaining three systems, which are very similar in components and operation, can be adapted to the garage. All feature removable aluminum beams and post shores with integral drop heads. The Skydeck and Tabla systems both contain a possible difficulty in their sheathing. The Skydeck system uses faced plywood while Tabla uses plastic plywood both of which can be expensive to repair or replace if modified. Considering the risk of potential damages for these rented formwork systems, the Titan HV system, using standard plywood sheathing, stands out as a potential alternate. Engineering Given that the Titan HV formwork system may be used for the garage, it must be professionally engineered to accommodate the slab s design. Manufacturers, such as Titan, typically have in-house engineering staff to design layouts and provide logistical support. The cost of these support services provided by Titan are included in the rental 25

32 Formwork System Selection (Continued) cost of the formwork. Additional costs may be incurred to have the formwork design approved and stamped by a professional engineer in the state. As the Navy League s garage is of a complex design, the use of any formwork system would have to be certified by a P.E.. Material Costs While engineering may be one cost of formwork systems, the majority of formwork erection costs are from labor and the system materials. Contractors can elect to rent either of these formwork systems, or make the investment to purchase the system s components. For the Navy League, the concrete subcontractor would most likely opt to rent the Titan system and use it on a trial basis. As listed under Cost & Production Factors, average costs for material rental of the Titan HV system versus a standard system indicate the standard system is less expensive. Despite including labor savings of 25% for the Titan HV system, its material costs of $0.80 / Sq. Ft. / Month are a large source of the $56, cost difference. However, $56, is only a small fraction of the building s total cost of $28 million. The cost difference is not substantial enough to eliminate the Titan HV. Labor Before the concrete subcontractor selects a system like Titan HV, labor costs and productivity must be taken into account. The Titan system was designed so that two men could erect 3,000 5,000 sq.ft. per day of a typical slab. With faster erection times, along with the drophead posts eliminating reshores, systems like Titans can produce as much as 30% labor savings. However, labor savings claims may not account for the type of labor. The labor force used on the Navy League is familiar with the standard metal system. Furthermore, seasoned superintendents may be hesitant to use an new type of formwork. Given these conditions, making the switch to a new system would initially cause inefficiencies and reduce potential labor savings. Local Codes Despite all the factors associated with formwork selection, one that overrides the others are the local building codes. Many manufacturers advertise low costs under the assumption that the decking and beam sections can be removed the day after pouring a slab. On the other hand, one must consider that many building codes are designed around the use of standard formwork and construction. Typically, code inspectors require a formal stripping letter (usually three days after a pour) before the formwork system can be removed and reshores added. In the 26

33 Formwork System Selection (Continued) case of the Navy League Building, Arlington county relies on the engineer of record to approve alternate stripping and reshoring procedures for the formwork system. If approved by the structural engineer, the Titan HV system can be used as advertised, and thus reduce material costs. Reusability To reinforce the sustainability theme of the building, formwork reusability should be addressed. Both the Titan HV and the handset aluminum system are designed to use plywood sheathing. The system as-built used ¾ thick, 4 x8 sheets of FSC Certified plywood. On average, the contractor was able to reuse each sheet (or smaller pieces) up to three to four times before it became unusable. If selected for the project, the Titan HV would use the same type of plywood. Considering the sheathing material, the environmental impact due to wood consumption is assumed to be equal for both types of formwork. Cost & Production Factors Formwork Cost & Production Factors Please see Estimating Notes * Standard System Titan HV System Average Framing Material Unit Cost $0.50 / Sq. Ft. / Month $0.80 / Sq. Ft. / Month (not including sheathing) 1 Sheathing Unit Cost 2 $1.19 / Sq. Ft. $1.19 / Sq. Ft. Average Labor Savings Up to 30% Formwork Construction Labor Unit Cost 4 $2.80 / Sq. Ft. $2.10 / Sq. Ft. Stripping & Reshoring Labor Unit Cost 4 $0.72 / Sq. Ft. $0.54 / Sq. Ft. Average Framing Total (not including sheathing) 5 $269,244 $430,791 Sheathing Total $54,598 $54,598 Formwork Construction Labor Total 4 $335,118 $251,339 27

34 Formwork Cost & Production Factors Cost & Production Factors (Continued) Please see Estimating Notes * Standard System Titan HV System Stripping & Reshoring Labor Total 4 $86, $64, Overall Material & Labor Total 6 $745, $801, Overall Cost Difference $56, in favor of the Standard System Estimating Notes: 1) Framing material cost data for the Standard System was obtained from a Washington D.C. area concrete contractor. Framing material rental cost data of the Titan HV System was obtained from the supplier. 2) Amount of sheathing required: [ 119,685 Sq. Ft. (total area) / 3 reuses] X 1.15 (waste factor) = 45,880 Sq. Ft. 3) Possible labor savings of up to 30% as advertised by manufacturer. Labor savings of 25% were used as conservative estimate in calculations. 4) Formwork construction and stripping & reshoring labor cost data for Standard System was obtained from a Washington D.C. area concrete contractor. Labor cost data for the Titan HV System was obtained from the Standard System s labor costs minus 25% in labor savings. 5) Material totals based off of 89,748 Sq. Ft. (approximately two entire levels) of framing needed during a 6 month construction period. 6) Overall material and labor totals based off of total elevated slab area; 119,685 Sq. Ft. Conclusion Considering the various factors used when selecting a formwork system, the pros and cons of the Titan HV system and handset aluminum system appear to balance. With the handset aluminum system providing a possible savings of over $56,000, it was concluded to be the most appropriate and most reliable system for the Navy League Building s parking garage. 28

35 Conclusion (Continued) While the Titan system may indeed produce labor savings, the lack of crews experienced with its installation indicate that a standard system is a conservative choice. Other than labor issues, another major factor is the garage s unusual design. The Titan HV may require modifications and custom-framed sections to conform to the irregular polygon shape of the building. The standard handset aluminum formwork system is more adaptable to the building and more compatible with the available labor force. In addition to labor issues, the environmental impact of each system was considered. Given that both systems accommodate plywood sheathing, both would require equal amounts of wood. Thus, the environmental impact of the standard system is equal to that of Titan HV. Although the analysis did not find pre-manufactured formwork to be more beneficial, it reinforced that the standard handset aluminum system is the best choice for Navy League. 29

36 The Green Building Reference Guide Executive Summary The Green Building Reference Guide is a website created to address the issues and requirements associated with green building projects. It is designed to assist construction professionals by organizing resources and information pertinent to a sustainable / LEED rated project s management and successful completion. These goals are accomplished through its simple navigation format and targeted content. While a multitude of available resources on sustainable / LEED buildings exists, the majority of this information is geared towards design professionals rather than construction professionals. Given this condition, research and surveys were conducted, indicating that a comprehensive database of resources would be a valuable tool for the industry. Based on research results, and through consultations with construction professionals, the GBRG was divided into five main topics: Material Procurement, Site Management, Waste Management, Indoor Environmental Quality, and Commissioning. Each main topic was further divided into subtopics which contain individual links to online resources. Rather than containing information within itself, the website is essentially a database of links to other sustainable and LEED rated construction websites. While the guide was designed to address the needs of general contractors, project managers, and other professionals, it is not intended to be exclusive to these groups. The guide can be of benefit to both builders and designers alike. Considering the potential benefits, initial user feedback was obtained to test the viability of the website. The overall positive response indicated that the website could indeed benefit the industry. By making the GBRG available online with routine maintenance, it has the ability of becoming a valuable reference tool in the expanding world of green construction. 30

37 Research & Analysis Introduction Overview: As The Navy League will be Arlington s first LEED rated office building, sustainable design components and methods are a clear choice for research. To achieve its Silver LEED rating, the project must be carefully planned not only in terms of design features and components, but also the acquisition of these components and their use. Considering that higher costs and more detailed planning may be associated with sustainable LEED construction, research questions can be developed using The Navy League Building as a basis for information. The underlying issue to address is the burden of sustainable design and LEED ratings on projects. Specifically, how can general contractors, construction managers, and other building professionals working on sustainable / LEED rated projects avoid unnecessary costs and delays through proper planning tools? To address their difficulties and management questions, a reference guide was created in the form of a website (HTML document). The content and functionality of the website was determined through in depth research on the materials and management processes used on sustainable / LEED projects. Analysis Outline: The basic steps of the website s creation are outlined below: Conducted preliminary research into LEED point system using text and internet-based sources Created and distributed surveys to industry professionals, building owners, and faculty among others Compiled, summarized, and organized resources into a logical graphic format for use online Goal: The overall goal of creating a reference guide is to provide an up-to-date list of reference sources in a straightforward and easily accessible format. While there exists a multitude of available resources on sustainable / LEED buildings, the majority of this information is geared towards design professionals rather than construction professionals. The website created from the research will be dedicated to assisting construction professionals. The more information available to builders of sustainable projects, the better the chances for their success. 31

38 Sustainable & LEED Construction Survey Overview To assist in the development of the reference guide, a sustainable design and LEED rated construction survey was distributed to industry professionals. The survey (found in the appendix on page 69) asked participants to describe some of the challenges they faced and list potential risks of green building projects. Participants were also asked their opinions on the usefulness of a reference guide specifically designed to assist the construction industry. In general, this survey data was intended to make the reference guide as practical and useful to builders as possible. Survey Results Survey results were obtained from individuals working for the general contractor and subcontractors on the Navy League Building. In total, six survey forms were completed and returned. While the amount of collected data is limited, the survey did provide some direction towards development of the reference guide. A selected question and a few of the responses are listed below. Survey Question: Do you believe a reference tool or guide outlining the potential cost, schedule, coordination, and other construction management issues in relation to sustainable / LEED design would be of benefit to construction professionals? Responses: Yes, (a guide) may give owners a real view of what its all about M.E.P. design professional Yes, any type of system that outlines potential risks is beneficial General contractor Yes, the knowledge is still limited in the field. This would help new people catch up faster General contractor Applications of Survey If nothing else, the survey results proved that creation of an online reference guide would be of benefit to green construction professionals. With proper development, the guide can become an outlet for industry resources and assist individuals unfamiliar with sustainable / LEED construction practices. 32

39 Reference Guide Development Form The internet has revolutionized the industrial world with its communication and information network capabilities. Given this easily accessible platform, the Green Building Reference Guide (GBRG) is designed in HTML (Hypertext Markup Language) format in order to be made available online for use by any building professional. Unlike printed material, the reference guide is intended to be free, updated regularly, and readily available to anyone with a computer and internet connection. In general, the GBRG is designed to assist construction professionals by organizing resources and information pertinent to the management and successful completion of green building projects. Rather than containing information within itself, the website is essentially a database of links to other sustainable and LEED rated construction websites. The difference between the GBRG and other sites is though its targeted organization and direct format. The GBRG is divided into five main topics: Material Procurement, Site Management, Waste Management, Indoor Environmental Quality, and Commissioning. Each main topic is further divided into subtopics which contain individual links to online resources. Main topics and subtopics were selected based on research and through consultations with construction professionals. Specifically, the website provides links to a variety of information such as moisture intrusion, waste avoidance, and commissioning practices among others. The common theme between the topics is that project managers may be required to use the information on sustainable and LEED rated construction projects. By using the GBRG, construction professionals can quickly and easily find desired topics rather than wading through a plethora of unrelated information and search results. Function The GBRG appears and functions similar to many websites, but with little fanfare. The main page is divided into separate frames featuring navigation menus and the content page window. As seen in the image on the following page, a header and navigation bar contains links to A.E. Senior Thesis related sites as well as the GBRG homepage. The homepage provides viewers with a brief introduction to the guide, its navigation techniques, and a list of comprehensive resources on sustainable and LEED construction. Underneath and to the left of the header, the directory menu contains links to the five main topics of the guide. Clicking on a box brings up the home page for the associated topic. 33

40 Reference Guide Development (Continued) Each topic homepage contains a brief overview of the topic and its relevance to green building construction. To the right of the homepage, a smaller navigation menu features the subtopics and the links to their individual content pages. The subtopic navigation menu allows users to see which page they are viewing out of all available for that category. Both the main topic and subtopic menus allow quick access to alternate topics without going back through previously viewed pages. Image of the Green Building Reference Guide Main Hompage Main Menu Directory Menu 34 Subtopic Menu

41 Reference Guide Development (Continued) Enlarged Images of the GBRG Menus Header and Main Menu Directory Menu Boxes are links Subtopic Menu Subtopics highlighted in yellow corresponding to page on-screen 35

42 Reference Guide Development (Continued) With the straightforward menu system, users can access their desired content pages quickly and easily. Upon arriving at a content page, users find a simple list of resource links available for the subtopic. The title of each resource, containing the link itself, is provided along with the company or organization that maintains the website. To further enhance the ease of navigation, all resource links open in new browser windows so that users may reference back to the GBRG. Image of the Recycling Subtopic Content Page (under the Waste Management main topic) Resource Title and Link Links open resource website in new browser window 36

43 Content Reference Guide Development (Continued) The intended benefit of the Green Building Reference Guide can be illustrated by the content contained within. The site was designed to be maintained on a regular basis and updated with new information. Each subtopic may be expanded with new resource websites as they are discovered and developed. Furthermore, new topics and subtopics can be created depending on industry trends as well user input. As stated on the homepage, the GBRG welcomes comments and improvement suggestions from users to make the guide a more helpful reference tool. Each website linked in the guide was reviewed in terms of its information content and applicability to the subtopic. Websites focusing solely on design issues or providing limited information on the topic were not included in the resource lists. By containing filtered content, the GBRG will allow building professionals quick access to the most detailed resources and can decrease productivity losses from unnecessary searches. The five main topics of the guide, Material Procurement, Site Management, Waste Management, Indoor Environmental Quality, and Commissioning, are essential issues to builders of sustainable and LEED rated projects. Considering time constraints and development of other Senior Thesis analysis topics, it was decided to narrow the scope of the GBRG s resource lists under these topics*. Therefore, the main topics of Waste Management and Indoor Environmental Quality were researched and developed to provide a sample of the GBRG s content if it is ever made fully operational. Waste Management: *Note: A site map of the GBRG is located in Appendix C. Waste management is a key issue to insure sustainable and LEED rated projects are successful. Careful planning of construction waste products and detailed documentation of how the waste is handled are of utmost importance. To address the multiple aspects of waste management, this section of the site is divided into the topics listed below: Waste Avoidance Packaging Waste Waste Removal Recycling Waste avoidance measures can be an easily overlooked topic on construction sites. By implementing some simple guidelines and practices, project managers can reduce unnecessary waste from construction and demolition activities. This 37

44 Reference Guide Development (Continued) section contains links to resources such as a list of guidelines for the proper handling and storage of gypsum wallboard, and Building Savings: Strategies for Waste Reduction of Debris from Buildings by the U.S. Environmental Protection Agency. The section entitled Packaging Waste is another topic to be considered by construction professionals. In many instances, excessive construction wastes can be reduced through efficient packaging of products and materials. Builder s have the option of either selecting manufacturers and suppliers already using efficient packaging and production methods, or simply asking the manufacturer / supplier to offer an alternate method in return for their patronage. To this end, a sample letter to a product vendor regarding a project s waste prevention / recycling program is linked. The last two topics, waste removal and recycling, are issues requiring detailed attention from general contractors. It is typically the responsibility of the G.C. to write and implement a waste management plan. Once a suitable waste management and recycling plan is established, the removal method for the various materials can be determined. Local regulations, site restrictions, available transportation routes, and documentation procedures are only a few factors which must be considered by project managers. These two sections contain links such as the Arlington County dumpster permit guide (applicable to the Navy League Building), and a recycling economics sample worksheet. Indoor Environmental Quality: Indoor environmental quality is an integral part of green building practices. Proper ventilation and the use of low VOC (volatile organic compounds), among many other issues must be addressed by builders on sustainable / LEED projects. In the case of LEED buildings, a total of 15 points is dedicated solely to indoor environmental quality. Given the importance of this topic, managers should develop and implement indoor air quality (IAQ) plans to insure a healthy working atmosphere for construction workers and building occupants. Some of the main issues to be addressed on an IAQ plan include: Moisture Intrusion Dust Intrusion & Reduction VOC Content of Materials Temporary Heat and Humidity Control The subtopic of moisture intrusion specifically relates to information and research on how to reduce mold and other potentially harmful effects of moisture. One useful tool 38

45 Reference Guide Development (Continued) provided in this section is the Indoor Air Quality Design Tool for School by the U.S. E.P.A. Apart from moisture, dust reduction on construction sites and low-voc content materials are two integral parts of indoor environmental quality. Construction workers can be exposed to many harmful types of dust which cause damage upon inhalation. To address this topic, the section on Dust Intrusion & Reduction contains links such as Control of Drywall Sanding Dust Exposures, by the NIOSH (National Institute for Occupational Safety and Health). The use of low-voc content materials affects both construction workers and building occupants alike. Materials with high levels of VOCs (Volatile Organic Compounds) can create illness and other health problems due to inhalation or prolonged exposure. To provide builders with information on the topic, links include the Low-Emitting Materials Table, by The Collaborative for High Performance Schools (CHPS), and Sources of Indoor Air Pollution Formaldehyde, by the U.S. E.P.A.. Given these websites, as well as the others provided, construction managers can learn the best methods of insuring indoor air quality. Reference Guide Utilization The possibilities for further expansion and development of the GBRG are boundless. By making the guide available online and with routine maintenance, it can become a valuable tool for building construction management. While the guide was designed to address the needs of general contractors, project managers, and other construction professionals, it is not intended to be exclusive to these groups. Architects and engineers can benefit from an increased understanding of green construction responsibilities just as builders should be aware of design requirements. Initial User Feedback To test the user-friendliness and viability of the GBRG, the website files were distributed to industry professionals with green construction experience. The positive feedback from respondents indicates that the GBRG would be a beneficial resource for green builders. A few of the comments received are listed below: 39

46 Initial User Feedback (Continued) Your website is very impressive. There is a lot of very useful content in it and linked to it. I agree with you that most sites and most LEED and sustainable discussions revolve around design. I think that the site you are making could be very useful for construction folks like us. quoted from a general contractor I just spent a little time on your site...wow, it is awesome. I think the layout is very user friendly, and I had no difficulty navigating the site. quoted from a general contractor Along with the comments, initial users also provided suggestions to improve the content and features of the guide. A majority of these suggestions were later incorporated into the website. Conclusion In conclusion, the Green Building Reference Guide was created to address the issues and requirements associated with green building projects. It is designed to assist construction professionals by organizing resources and information pertinent to a sustainable / LEED rated project s management and successful completion. Through the GBRG s simple navigation format and targeted content, this goal is accomplished. Positive feedback from individuals illustrated how the website fills a niche among the currently available resources. Considering the initial response, the GBRG has the potential of becoming a valuable reference tool in the expanding world of green construction. 40

47 Structural Redesign of Office Tower Executive Summary Determining the most appropriate structural system can be a challenging task for building designers. With this in mind, a cast in place concrete office tower was analyzed and compared to the Navy League Building s current structural steel system. Using structural analysis software, a post-tensioned flat slab system was designed to mimic the layout of the current structure and provide a schematic for estimating and scheduling purposes. The alternate system was estimated to have a total cost of $860,000 above the steel system and require 1.5 weeks longer to construct. Despite these shortcomings, the concrete structure was able to increase ceiling plenum space, provide comparable environmental benefits, and allow use of the Titan HV formwork system described in the Alternate Formwork System Evaluation. Considering the initial goals of reducing the project s cost and schedule were not met, the concrete system was not determined to be the best system. Overall, the original steel system was concluded to be the most appropriate structure through its value to the owner. 41

48 Thesis Research & Analysis Plan Overview: The analysis comprising the breadth requirements of Senior Thesis is a constructability review and redesign of the Navy League s office tower. This analysis was recommended by Mr. Bill Moyer, the Vice President of Base Building for Davis Construction. As recommended by an experienced general contractor, the underlying notion is that maintaining a cast in place concrete structure is more efficient than the actual CIP garage and steel office tower combination. The current tower consists of a structural steel frame and a panelized precast façade. Some unfavorable issues related to the structural steel frame include the depth of the members, the lead time associated with steel shop drawings and procurement, the increasing costs of structural steel, and connections between the frame and the precast panels. As an alternative to the structural steel frame, the viability of a cast in place concrete frame will be analyzed. Additionally, potential mechanical system coordination conflicts due to the new frame will be examined. Using a configuration that mimics the original steel frame, a concrete frame will be able to integrate directly with the concrete parking deck. This system also has the benefits of increased plenum space and the ability for precast panel anchors to be imbedded in the frame. While the CIP system appeared to provide the benefits described above, an initial feasibility study was necessary prior to its selection as a thesis topic. Consequently, initial estimates were prepared to indicate the costs and time associated with a CIP office tower. R.S. Means 2004 Assembly Cost data was utilized and the original schedule served as a basis for estimated durations. As shown in the chart below, the overall cost / S.F. of the steel system is $14.24 while a concrete system was estimated to be $ The original schedule to complete the steel structure (including decks and fireproofing) was approximately 34 weeks while the alternate CIP structure was estimated at 32 weeks. Considering the similarity of the initial estimates, a detailed analysis will prove its worth in determining the most appropriate structural system. Assemblies Estimate Assemblies Estimate Cost Assemblies Estimate Cost / S.F. Erection Duration Steel Structure $3,065,881 $ weeks CIP Structure (Alternate) $3,886,672 $ weeks * Note: Costs were adjusted for 89.4% Arlington, VA location factor 42

49 Thesis Research & Analysis Plan (Continued) Analysis Outline: The basic steps of analyzing the topic are outlined below: Gather detailed erection data and structural analysis methods on CIP concrete construction (from general contractor and AE faculty) Determine beam sizes based on ceiling height requirements and ACI code Establish slab thickness by ACI code Determine floor and frame loads using BOCA National Building Code Complete frame analysis Prepare budget and schedule for alternate system Compare alternate budget and schedule to steel system and select structure with greater cost / benefit ratio Goal: Similar to the alternate formwork system, the main goal of the analysis is to determine if reductions in the structure s budget and schedule are possible by using CIP concrete. One way reductions may be achieved is through the minimization of trades for superstructure erection. Another goal of the redesign is to determine if a concrete structure can reduce the environmental impact of the building. Selection of the most appropriate structure corresponds with the Navy League Building s LEED rating and sustainable design theme. Images of the current structural steel system during erection 43

50 Concrete Structure Design Development The first step in designing a cast in place concrete structure for the Navy League s office tower is to examine the characteristics of the original steel system. Design criteria such as floor to floor height, maximum beam spans, and floor loading are listed in the table below. These criteria were used to determine the design of the concrete system in order to maintain the building s current structural layout as much as possible. One of the most important criteria was the maximum span of 43 for the open plan office spaces. In order to maintain this clear span without column interruptions, it became evident that post-tensioning must be used. Characteristics of Current Structural Steel System Dimensions Floor to Floor Height 13-4 Maximum Member Depth 24 Composite Slab Thickness 6 Maximum Bay Span 38 Live Loads* Office 80 psf Filing / Mechanical Penthouse 150 psf Lateral Loads* Wind Speed 80 M.P.H. Wind Load Importance Factor 1.0 Wind Exposure B Seismic Load* Peak Velocity Related Acceleration Av < 0.05 Peak Acceleration Aa < 0.05 Seismic Hazard Exposure Group II Seismic Performance Category A Soil Profile Type S1 General Notes* Loads per BOCA National Building Code,

51 Concrete Structure Analysis To assist in the concrete design of the tower, the structural analysis software Adapt-PT was utilized. This software allows users to input design characteristics such as slab thickness, span length, column dimensions, and Slab Type Two-way, Flat Slab Slab Dimensions other variables. Once the data is Thickness (in) Tributary Width (ft) Span Length (ft) entered, the program determines if the to 43 structure is able to withstand gravity Drop Panel Dimensions Width (in) Length (in) Depth (in) loads and other forces including punching shear based on ACI design Concrete codes. Strength (psi) Unit Weight (psf) Columns Beams Slab The design characteristics of the (Normal weight) new system can be seen in the table on Steel Reinforcement the right. As shown, a two-way flat slab design including drop panels was selected for its ease of construction and 60 ksi Post-Tensioning Cables System Type Area of Tendons its potential for increasing plenum space. Unbonded in^2 (7/16" Diam.) After calculating a variety of depth Loading and span iterations, a final design was Design Load Type Typ. Floor Roof selected for the slab and drop panels. Uniform 80 psf 100 psf The post-tensioned slab is 12 thick, and Columns supported by 14 x 14 columns with 36 x 36 x 8 drop panels to resist punching Size 14" x 14" Floor to Floor Height 13' - 6" shear. Given this information, Adapt-PT also determined the total pounds of steel reinforcement and post-tensioning cable required for the design. While Adapt-PT does account for forces associated with gravity loads, it does not consider other forces the building must withstand such as sway from seismic and wind loads. Considering this, the C.I.P. concrete structure should not be considered as a complete design. The system 36 x 36 x 8 Deep Drop Panel, Typical 12 Thick Post-Tensioned Slab Post-Tensioning Design Characterisitics Bar Yield Strength (fy) Modulus of Elasticity Clear Bar Cover 29,000 ksi 1" Ultimate Tendon Strength 270 ksi described above is only a basic schematic used to analyze the feasibility of a concrete tower. Rendering of C.I.P. Concrete Slab, Columns, & Drop Panels 45

52 Budget Comparison Budget and Schedule Comparison Using the basic design characteristics of the C.I.P. concrete tower and the steel tower as-built, a budget and schedule were compiled using R.S. Means cost data. As seen in the tables at right, detailed estimates were performed for each structural system. The resultant cost of the concrete tower was roughly $3.5 million and approximately $16.00 per square foot of building area. The majority of the cost for this system can be attributed to the elevated slab installation. Despite being a relatively simple flat slab design, formwork installation and concrete placement are expensive activities. The steel tower proved to be the least expensive option with a total cost of roughly $2.6 million, or $12.00 per square foot. As seen in the table, the cost of fireproofing was also included in the total as it would not be necessary if the tower was constructed in concrete. Given the total estimated cost of each system, it would appear that steel is the best option for the tower. A post-tensioned concrete tower would cost over $860,000 more than one of steel. While the total cost margin is substantial, one must consider other factors not included in the estimates. One of the most important factors is the cost associated with precast panel connections. To accommodate the Navy League Building s architectural precast façade panels, custom brackets had to be fabricated and installed on the steel frame. If the frame was concrete, panel brackets could be imbedded into the 12 flat slab. The material and installation costs for the imbedded brackets would most likely be less than the costs of brackets for the steel frame. Apart from structural details, other costs could be reduced with a concrete system. If the concrete subcontractor installed both the parking garage and office tower, planning and mobilization costs for steel erection would be eliminated. Concrete Superstructure Costs Description TOTALS Total Building Sq.Ft. 212,947 Columns $285,532 Elevated Slab $3,082,760 Post-Tensioning Cable $253,388 Total Concrete Superstructure Cost (after 90.7% location factor adjustment, R.S. Means 2005) Superstructure Cost per Square Foot of Building Area Steel Superstructure Costs Description $3,478,007 $16.33 TOTALS Total Building Sq.Ft. 212,947 Structural Steel $1,827,997 Concrete, Metal Deck, and Accessory $875,535 Fireproofing $222,011 Total Steel Superstructure Cost (after 89.4% location factor adjustment, R.S. Means 2004) Superstructure Cost per Square Foot of Building Area $2,615,435 $

53 Schedule Comparison Budget and Schedule Comparison (Continued) As total costs for the steel structure were found to be lower than concrete, steel also proved to have a lower overall duration. Using R.S. Means 2005 daily crew output data for each activity, the approximate duration for concrete placement was calculated to be 17 weeks. As scheduled by the general contractor, the time needed to erect steel was only 15.5 weeks. Despite the 1.5 week time difference, both systems were considered to be equal in terms of construction time. Accounting for variations in crew sizes and the longer time needed for steel fabrication, 1.5 weeks is a negligible difference. * Please see the Appendix for estimate spreadsheets. Description Superstructure Durations TOTALS (weeks) Structural Steel Shop Drawings & Fabrication (Time not included in total duration) 22.0 Erection 14.5 Install & Pour Deck 13.0 Fireproofing 9.0 Total Duration (Adjusted for concurrent activities) 15.5 C.I.P. Concrete Columns 3.0 Elevated Slabs 16.0 Post-Tensioning 8.0 Total Duration (Adjusted for concurrent activities) 17.0 Structural & M.E.P. Coordination Coordination between a building s structural system and mechanical equipment must be addressed during the design process. To insure that the posttensioned flat slab structure would not conflict with the Navy League Building s V.A.V. ductwork and components, overlays of each system were created. As seen in the image on the left, there are no apparent coordination issues with a concrete structure. By retaining the existing column layout and bay sizes, the alternate structure can easily accommodate the M.E.P. system. Additionally, the 12 thick flat slab system is able to dramatically increase plenum space. Considering the majority of steel beams are 21 deep in the original system, the concrete system would increase plenum H.V.A.C. Plan with C.I.P. System Overlay 47

54 Structural & M.E.P. Coordination (Continued) space from 7 to 15 (depending on the location of drop panels). Increasing ceiling plenum space helps reduce M.E.P. coordination, and can potentially reduce mechanical system costs. Applications of the Alternate Formwork System Considering the simple, repetitive design of the concrete structure, the Titan HV system has another potential application. Analyzed for the Alternate Formwork System Evaluation, the Titan HV system could have a positive impact on the total cost and duration of the proposed structure. While Titan HV may not be the best type of formwork for the parking garage, it may be able to increase production rates and provide other benefits if selected for the office tower. Environmental Impact: Concrete vs. Steel Selecting the most appropriate structural system should be determined not only by cost and schedule, but also the environmental impact of the system throughout its lifecycle. In terms of concrete vs. steel, there is much debate as to which material is more green. Proponents of steel note that it is a 100% recyclable material and it can be recycled continuously without degradation to its physical properties. Steel also allows for clean, dust-free construction with minimum site waste 11. Furthermore, when steel structures reach the end of their life span, the members can sometimes be reused rather than scraped. While steel has many favorable attributes, concrete can also be considered an environmentally friendly material. Concrete can be made from local materials, namely the fine and coarse aggregates used in the mix. Concrete is also recyclable in that it can be crushed and used for fill and aggregate in asphalt among other applications. Besides being green in itself, concrete also reduces wastes from steel production. Fly ash and blast-furnace slag, by-products of steel production, can be used in concrete mixes rather than being disposed in landfills 12. In general, research suggests that the environmental benefits of steel construction are comparable to those of concrete construction. Given this conclusion, either structural system would adequately maintain the sustainable design ideals of the LEED rated Navy League Building. *Note: Superscripts correspond to citations in the References section 48

55 Conclusion Through the detailed analysis and design of an alternate structural system, it is concluded that post-tensioned C.I.P. concrete would be a viable option for the Navy League Building s office tower. Selecting the concrete structure would reduce mobilization of trades on site, reduce the amount of mechanical system coordination, and help provide an environmentally friendly building in line with the project s LEED rating. The simple flat slab design would also allow use of an efficient premanufactured formwork system such as the Titan HV. In contrast, while a concrete system may be viable, it is not necessarily the best structure for the building. The steel system offers a substantially lower cost, a (potentially) shorter erection duration, and similar advantages in terms of its environmental impact. Overall, the original steel system is considered to be the most appropriate structure through its value to the owner. 49

56 References The following list contains the resources used in the Senior Thesis research and analysis of. The resources are organized according to analysis topic. Alternate Formwork System Evaluation 1) Hanna, Awad S., Sanvido, Victor E., Interactive Horizontal Formwork Selection System. The Interactive Horizontal Formwork Selection System provides a description of available formwork systems and their various applications. As used in the Alternate Formwork System Evaluation, the guide also provides a reference table for selecting the most appropriate system based on building conditions. 2) Peri, Aluminum Slab Formwork, Skydeck, < 44/productcategory_ID/15.cfm> Peri, a German manufacturer of formwork systems, produces a panelized slab formwork system known as Skydeck. The website provides a product description and technical specifications of the Skydeck system, as referenced in the alternate formwork comparison. 3) The Titan HV Shoring System, product reference guide, Titan Formwork Systems, LLC (Information also accessed at ) The product guide and website provided by Titan Formwork provides a description and technical specifications of the Titan HV system, as referenced in the alternate formwork comparison. The Green Building Reference Guide 4) Field Guide for Sustainable Construction, The Pennsylvania State University, June The field guide is a comprehensive resource providing typical practices and suggestions for use on green building projects. The field guide was used extensively in the development of the Green Building Reference Guide website. 50

57 References (Continued) 5) Holzner, Steven. HTML Black Book, The Coriolis Group, This guidebook provides an in-depth description of HTML code creation and editing. The book provided a background on the most efficient HTML format for the Green Building Reference Guide website. Structural Redesign of Office Tower 6) Battles, Stephanie J., Robert Adler. Production, Energy, and Carbon Emissions: A Data Profile of the Iron and Steel Industry. American Council for an Energy Efficient Economy Summer Study on Energy Efficiency in Industry, June < > This report provides energy consumption and emission quantities of the iron and steel production industry from 1985 to ) ICC (International Code Council). BOCA National Building Code, The BOCA 96 code was used throughout the original design of the Navy League Building, as mandated by law. The code provides a variety of construction practice and design information such as floor and wind load values. Use of the BOCA code was necessary in the design of the concrete office tower structure. 8) Nilson, Arthur H., David Darwin, Charles W. Dolan, Design of Concrete Structures, McGraw Hill, Design of Concrete Structures is the textbook used in A.E. concrete design courses. This text provided a basis of concrete design criteria and equations for the analysis. 9) Reed Construction Data. Means Building Construction Cost Data 2005 Book. 63 rd Edition. Reed Business Information. Kingston, MA Means is an indispensable building cost estimating guide used to determine the approximate total cost and duration of the alternate structural system. 51

58 References (Continued) 10) Ritz, Dr. P., Civil Engineer ETH., P. Matt, Civil Engineer ETH., C. Tellenbach, Civil Engineer ETH., P. Schlub, Civil Engineer ETH., H.U. Aeberhard, Civil Engineer ETH., Post-Tensioned Slabs, VSL International Ltd., Berne, Switzerland, This report by VSL provides the fundamental design process and construction procedures, among other information, on post-tensioned slabs. The document provided an overview of posttensioning systems and assisted in the design of the concrete office tower structure. 11) Sustainable Steel Construction. The Corus Group. < > The Sustainable Steel Construction website features information on the life-cycle of structural steel components. 12) Vares, Sirje., Tarja Hakkinen. Environmental Burdens of Concrete and Concrete Products. < > Nordic Concrete Research Website. This technical report provides detailed data and statistics on the environmental impact of concrete and cement production. 52

59 Appendices This section includes: Appendix A - Project Introduction & Background Information Pages Appendix B - Alternate Formwork System Evaluation Appendix C - The Green Building Reference Guide Appendix D - Structural Redesign of Office Tower Pages Pages Pages

60 Appendix A Project Introduction & Background Information 54

61 Project Cost Evaluation Detailed Systems Estimate Description Unit Quantity Superstructure Estimate Summary Costs Unit Material Cost Material Cost Unit Labor Cost Labor Cost Unit Equipment Equipment Cost Cost Total Cost Structural Steel Members Level 2 Tons ,325 $150, $37, $12,826 $200,668 Level 3 Tons ,325 $133, $33, $11,424 $178,745 Level 4 Tons ,325 $137, $34, $11,696 $182,988 Level 5 Tons ,325 $126, $31, $10,758 $168,314 Level 6 Tons ,325 $119, $29, $10,159 $158,943 Level 7 Tons ,325 $119, $29, $10,159 $158,943 Penthouse & Machine Tons Room ,325 $153, $38, $13,119 $205,265 Penthouse Tons Roof ,325 $23, $5, $1,989 $31,117 Columns Tons ,325 $341, $85, $29,143 $455,967 Structural Steel Subtotal $1,740,950 Add for Member Connections % 5.0 $87,047 Total Structural Steel Cost $1,827,997 55

62 Project Cost Evaluation Detailed Systems Estimate Description Unit Quantity Superstructure Estimate Summary Costs Unit Material Cost Material Cost Unit Labor Cost Labor Cost Unit Equipment Equipment Cost Cost Total Cost Concrete Placement, Metal Deck, and Accessories Concrete Placement C.Y. 3, $262, $47, $20,525 $330,447 Concrete Finishing S.F. 230, $105, $50,667 $156,606 Metal Deck S.F. 230, $211, $64, $4,606 $280,970 Welded Wire Fabric C.S.F. 2, $21, $44,103 $65,752 Shear Studs EA. 34, $13, $20, $8,004 $41,760 Total Concrete Placement, Metal Deck, and Accessory Cost $875,535 Subtotal: Structural Steel and Concrete Placement, Metal Deck, and Accessory Cost $2,703,532 TOTAL Superstructure Cost (after 89.4% location factor adjustment) $2,416,957 Superstructure Cost per Square Foot of Building Area ( Building Area = 212,947 S.F. from A100 of contract drawings ) $

63 Navy League Project Schedule Todd Bookwalter Oct :50 Activity ID Activity Name Original Remaining Schedule % Start Finish R. Duration Duration Complete A1000 PRECONSTRUCTION 0 0 0% Jan-03-00* A1940 Existing Bldg. Demolition % Jan Jun A1390 Base Building Permits % Oct-24-00* May A1420 Base Building Design % Sep-04-01* Dec A1560 Issue DAVIS Full Notice to Proceed 1 0 0% Mar A Mar A A1930 BEGIN CONSTRUCTION 0 0 0% May A A1950 Jobsite Mobilization / Erosion Controls 5 0 0% May A May A A6660 Excavation & Sheeting to Subgrade % May-16-03* Apr A2650 Begin Concrete 0 0 0% Jan A A2660 Footings / Walls / Columns 5 0 0% Jan A May A A2760 Underground MEP & Drainage % Feb A May A A2770 Columns & Walls to B % Mar A May A A2840 Columns & Walls to B % Mar A Jun A A2780 B-4 Slab on Grade % Mar A May A A2790 B-3 Suspended Slab 3 0 0% Mar A Jun A A2640 Complete Excavation / Sheeting to S % Apr A Apr A A2850 B-2 Suspended Slab % May A Jun A A2860 Columns & Walls to B % May A Jul A A2870 B-1 Suspended Slab % Jun A Jul A A2880 Columns & Walls to 1st floor % Jul A Aug A A2890 1st Floor Suspended Slab % Jul A Aug A A2940 Begin Structural Steel Erection 0 0 0% Aug A A2950 Erect Steel - East Side (L1 - L7) to C % Aug A Oct A A4660 B-4 MEP Risers % Sep-08-04* Sep A3220 Install Metal Decking / Studs: East Si % Sep-08-04* Oct A4670 B-3 MEP Risers % Sep-22-04* Oct A4770 B-4 Core and Shell Finishes % Sep-22-04* Nov A3570 Fireproofing: East Side L2 - Roof % Sep-29-04* Oct A4680 B-2 MEP Risers % Oct-06-04* Oct A4780 B-3 Core and Shell Finishes % Oct-06-04* Nov A3070 Erect Steel - West Side L1 - Penthouse % Oct-11-04* Dec A3230 Pour Metal Decking: East Side L2 - P % Oct-14-04* Nov A3700 Erect Precast - East Side % Oct-15-04* Dec A4690 B-1 MEP Risers % Oct-20-04* Nov A4790 B-2 Core and Shell Finishes % Oct-20-04* Dec A5970 Install Facade Windows / Curtainwall % Oct-22-04* Jan A3210 Install Metal Decking / Studs: West S % Oct-26-04* Dec A3240 Pour Metal Decking: West Side L % Oct-28-04* Dec A3560 Fireproofing: West Side L2 - Roof % Nov-01-04* Dec A4700 L1 MEP Risers % Nov-03-04* Nov A4800 B-1 Core and Shell Finishes % Nov-03-04* Dec A5760 Install Lobby Ductwork Above Ceiling % Nov-04-04* Nov A5940 Main Lobby / Meeting Rooms / Core % Nov-04-04* Mar A4710 L2 MEP Risers % Nov-17-04* Dec A4810 Core Finishes - 1st Floor % Nov-17-04* Mar A5770 Install Lobby Sprinkler Piping Rough-in 5 5 0% Nov-18-04* Nov A5780 Install Lobby Electrical Rough - in 5 5 0% Nov-18-04* Nov A5800 MEP Rough-ins / Finishes - 1st Floor 8 8 0% Nov-24-04* Dec A3690 Complete all Perimeter Fireproofing 0 0 0% Dec-02-04* A4720 L3 MEP Risers 5 5 0% Dec-03-04* Dec A4930 Core Finishes - 2nd Floor % Dec-03-04* Mar A4460 Install Elevators % Dec-07-04* Apr A4540 Final Elevator Inspections 5 5 0% Dec-07-04* Dec A4550 Pour all Penthouse Mechanical Pads 5 5 0% Dec-07-04* Dec A4580 Penthouse MEP Work % Dec-07-04* Apr A3830 Erect Precast: West Side / Caulk Pre % Dec-10-04* Feb A4730 L4 MEP Risers 5 5 0% Dec-10-04* Dec A4940 MEP Rough ins / Finishes - 2nd Floor 8 8 0% Dec-10-04* Dec A5070 Core Finishes - 3rd Floor % Dec-10-04* Mar A5830 Lobby Rough-in MEP to Ceilings and % Dec-13-04* Dec A4560 Hoist and Set all Penthouse Equipm % Dec-14-04* Dec A4740 L5 MEP Risers 5 5 0% Dec-17-04* Dec A5080 MEP Rough ins / Finishes - 3rd Floor 8 8 0% Dec-17-04* Dec A5210 Core Finishes - 4th Floor % Dec-17-04* Mar A6080 Install Stone to Precast, East Half of % Dec-17-04* Dec A5840 Lobby Close in Inspections - All Trades 5 5 0% Dec-20-04* Dec A6090 Install Stone to Precast, N. Wayne St % Dec-22-04* Dec A4750 L6 MEP Risers 5 5 0% Dec-27-04* Jan A5220 MEP Rough ins / Finishes - 4th Floor 8 8 0% Dec-27-04* Jan A5350 Core Finishes - 5th Floor % Dec-27-04* Apr A6210 Curb & Gutter / Pavers / Sidewalk % Dec-27-04* Jan A5980 Facade Windows / Curtainwall (West % Dec-28-04* Feb A4570 Piping for Penthouse Equipment % Dec-29-04* Jan A4760 L7 MEP Risers 5 5 0% Jan-04-05* Jan Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb ar PRECONSTRUCTION Existing Bldg. Demolition Base Building Permits Base Building Design Issue DAVIS Full Notice to Proceed BEGIN CONSTRUCTION Jobsite Mobilization / Erosion Controls Excavation & Sheeting to Subgrade Begin Concrete Footings / Walls / Columns Underground MEP & Drainage Columns & Walls to B-3 Columns & Walls to B-2 B-4 Slab on Grade B-3 Suspended Slab Complete Excavation / Sheeting to Subgrade B-2 Suspended Slab Columns & Walls to B-1 B-1 Suspended Slab Columns & Walls to 1st floor 1st Floor Suspended Slab Begin Structural Steel Erection Erect Steel - East Side (L1 - L7) to Column Line 6 B-4 MEP Risers Install Metal Decking / Studs: East Side L2 - Penthouse B-3 MEP Risers B-4 Core and Shell Finishes Fireproofing: East Side L2 - Roof B-2 MEP Risers B-3 Core and Shell Finishes Erect Steel - West Side L1 - Penthouse Pour Metal Decking: East Side L2 - Penthouse Erect Precast - East Side B-1 MEP Risers B-2 Core and Shell Finishes Install Facade Windows / Curtainwall (East Half) Install Metal Decking / Studs: West Side L2 - Penthouse Pour Metal Decking: West Side L2 - Penthouse Fireproofing: West Side L2 - Roof L1 MEP Risers B-1 Core and Shell Finishes Install Lobby Ductwork Above Ceiling Main Lobby / Meeting Rooms / Core Finishes L2 MEP Risers Core Finishes - 1st Floor Install Lobby Sprinkler Piping Rough-in Install Lobby Electrical Rough - in MEP Rough-ins / Finishes - 1st Floor Complete all Perimeter Fireproofing L3 MEP Risers Core Finishes - 2nd Floor Install Elevators Final Elevator Inspections Pour all Penthouse Mechanical Pads Penthouse MEP Work Erect Precast: West Side / Caulk Precast L4 MEP Risers MEP Rough ins / Finishes - 2nd Floor Core Finishes - 3rd Floor Lobby Rough-in MEP to Ceilings and Bulkheads Hoist and Set all Penthouse Equipment and Piping L5 MEP Risers MEP Rough ins / Finishes - 3rd Floor Core Finishes - 4th Floor Install Stone to Precast, East Half of Clarendon Rd. Side Lobby Close in Inspections - All Trades Install Stone to Precast, N. Wayne Street Side L6 MEP Risers MEP Rough ins / Finishes - 4th Floor Core Finishes - 5th Floor Curb & Gutter / Pavers / Sidewalk Facade Windows / Curtainwall (West Half) Piping for Penthouse Equipment L7 MEP Risers Actual Work Remaining Work Critical Remaining Work Milestone Summary TASK filter: All Activities Primavera Systems, Inc. Page 1 of 2

64 Navy League Project Schedule Todd Bookwalter Oct :50 Activity ID Activity Name Original Remaining Schedule % Start Finish R. Duration Duration Complete A5360 Mechanical Rough ins / Finishes - 5t % Jan-04-05* Jan A5490 Core Finishes - 6th Floor % Jan-04-05* Mar A5500 Mechanical Rough ins / Finishes - 6t % Jan-11-05* Jan A5630 Core Finishes - 7th Floor % Jan-11-05* Apr A5640 Mechanical Rough ins / Finishes - 7t % Jan-18-05* Jan A6580 Landscaping & Complete Sitework % Jan-20-05* Apr A6410 Install Street Light Conduit / Pole Ba % Jan-26-05* Feb A4370 Building Dry in / Detailing / Caulking % Feb-10-05* Mar A5890 Install Stone on Lobby Walls % Feb-16-05* Mar A6100 Install Stone to Precast, Wilson Blvd % Feb-24-05* Mar A6110 Install Stone to Precast, N. Adams St % Feb-24-05* Mar A6120 Install Stone to Precast, West Half of % Feb-24-05* Mar A4610 Install Penthouse Electrical Power F % Mar-03-05* Mar A5910 Install Millwork Panels in Main Lobby % Mar A Mar A A4450 Building Envelope Complete 0 0 0% Mar-09-05* A6130 Stone on Precast Complete 0 0 0% Mar-09-05* A4640 Commissioning of Penthouse Equip % Apr-07-05* Apr A5740 Complete all Core and Shell Finishes 0 0 0% Apr-15-05* A6620 Final Inspections 5 5 0% Apr-21-05* Apr A6640 Substantial Completion - Base Building 0 0 0% Apr-27-05* Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb ar Mechanical Rough ins / Finishes - 5th Floor Core Finishes - 6th Floor Mechanical Rough ins / Finishes - 6th Floor Core Finishes - 7th Floor Mechanical Rough ins / Finishes - 7th Floor Landscaping & Complete Sitework Install Street Light Conduit / Pole Bases Building Dry in / Detailing / Caulking Install Stone on Lobby Walls Install Stone to Precast, Wilson Blvd. Side Install Stone to Precast, N. Adams St. Side Install Stone to Precast, West Half of Clarendon Rd. Side Install Penthouse Electrical Power Feeds, panels, etc. Install Millwork Panels in Main Lobby Building Envelope Complete Stone on Precast Complete Commissioning of Penthouse Equipment Complete all Core and Shell Finishes Final Inspections Substantial Completion - Base Building Primavera Systems, Inc. Page 2 of 2

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