TABLE OF CONTENTS. William Penn Charter School. Executive Summary 2. Proposal Letter 3. Existing Conditions 4

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1 TABLE OF CONTENTS Executive Summary 2 Proposal Letter 3 Existing Conditions 4 Site Renovation Planning & Subsurface Case Study 13 4D CAD & 4D Site Planning 25 Structural Proposal 33 Structural Analysis 38 Conclusions & Recommendations 45 Appendix --- 1

2 Executive Summary The analysis of the Site Improvements and New Middle School Building consists of three main topics. These topics are Site Renovation Planning, 4D CAD Site Planning, and a Pre-cast Concrete Plank Floor System. Focusing on these subjects helped to find possible ways to increase the value of the project for all members of the project team. Site Renovation Planning is an important part of construction. A good plan will go a long way, and a project without a plan will have situations to deal with that could have been avoided. A successful plan is easier developed if everyone on the project team communicates with one another. This is especially important between the Owner and Contractor. These lines of communication should be opened well before the contract is signed and should be continuous throughout the entire length of the project. Developing a 4D CAD model can help a project team open the lines of communication and work together to create a successful plan. On smaller projects it may not be an economical solution. Therefore, on smaller projects the project team should concentrate on developing a plan that can allow others involved with the project to mentally see the means of completing the project correctly. A pre-cast plank system is an economical floor system alternative and has multiple benefits. Although it may only produce minor cost savings, it reduces some complexity during the construction phase. All of these topics will be discussed in more detail and will be examined for advantages and disadvantages to determine whether the suggestions add value to the Site Improvements and New Middle School Building at Penn Charter. 2

3 April 16, 2003 Mr. Hal Davidow Chief Financial Officer 3000 West School House Lane Philadelphia, PA Re: Site Improvements and New Middle School Building Dear Mr. Davidow: The information in this summary book pertains to the Site Improvements and New Middle School Building at. This information is in response to your request in August 2002 for information leading to a project with better value. The information has been compiled in this report as well conclusions and recommendations for the following items listed below: Site Renovation Planning Subsurface Case Study 4D CAD 4D Site Planning Pre-cast Plank Floor Systems All supplemental information for each section can be found in the Appendix under the corresponding section. Additional information is also located on the internet at Sincerely, Daniel J. Packer Penn State University 3

4 EXISTING CONDITIONS 4

5 Existing Conditions Introduction was established in 1689 by William Penn. It is the oldest Quaker School in the world and has high academic standards while providing significant opportunities for athletic excellence as well. Located on a 45 acre campus in the East Falls section of Philadelphia, students can attend Penn Charter from kindergarten through 12 th grade. The school enrollment currently is approximately 855. The Site Improvements and New Middle School Building Project set out to accomplish two significant goals. The first goal was to improve the conditions of the sub-par landscape at the Penn Charter campus. The campus did not have a logical traffic flow or enough parking spaces to meet the Middle School demand of the students and faculty. The campus also needed upgrading in multiple site utilities to service the new construction as well as existing construction. The site design also needed to accommodate the strong Performing Arts possibility that within two years after completion of construction, that a New Performing Arts Center would be built adjacent to the Lower School Building. See the above figure for the location of the New Middle School Building and the Performing Arts Center. The second goal of the project was to expand the number of educational facilities on campus due to the increase in enrollment and lack of space in existing buildings. Currently kindergarten through 5 th grade attended classes in the Lower School building. From 6 th grade thru 12 th grade, students spent most of their day in the Main Building on campus. The New Middle School will relieve the Main Building of approximately 250 5

6 students from the 6 th grade thru 8 th grade. It was designed to match the older style buildings on the Penn Charter Campus while introducing a hint of modernism to the site. Primary Project Team Owner: General Contractor: Architect: Landscape Architect/ Civil Engineer: Structural Engineer: MEP Engineer: Acoustical Consultant: Intech Construction, Inc. Bower Lewis Thrower Cairone & Kaupp, Inc. O Donnell & Naccarato Paul H. Yeomans, Inc. Metropolitan Acoustics Penn Charter Location and Site Site The campus location in East Falls is approximately five to ten minutes from downtown Philadelphia. The site neighbors Philadelphia University as well as residential neighborhoods. Four primary buildings and multiple athletic fields and tennis courts occupy the 45 acre site. The New Middle School site was formerly tennis courts that were demolished as part of this project. Access to the site includes major interstates such as I-76 and I-95. Deliveries from all directions can use major roadways to access the site despite the residential location. Penn Charter was originally Downtown Philadelphia located in downtown Philadelphia until the school was moved to its current location in the early 1900s. The site is historic and caused many subsurface unknowns to arise during the construction. 6

7 Building Function and Primary Uses The New Middle School is a multi-use facility for grades six through eight. The building consists of classrooms, offices, science classrooms, mechanical and electrical rooms, mechanical penthouse, unfinished basement space, as well as a commons area. Dates of Construction The project start date was May 29, This began Phase 1 of the project which included various site improvements. Phase 1 was to be substantially complete by September 3, 2001 by contract. Building excavation was scheduled to begin on June 20, Phase 2, which included the New Building and the remainder of the site improvements, was scheduled to be complete by August 15, See the end of this section for the summary schedule. Project Delivery Method On this job a General Contractor was in charge of the work (see Organizational Chart below). Subcontractors, who held contracts directly with the General Contractor, performed the majority of the work. Self-preformed work by the General Contractor included frames, doors, hardware, millwork, and casework. The General Contractor was Fixed Fee Penn Charter (Owner) GMP Bower Lewis Thrower (Architect) Intech Construction Inc. (General Contractor) Cairone & Kaupp (Landscape, Civil) O Donnell & Naccarato (Structural) Salvino Steel (Structural Steel) H.T. Sweeney (Site Contractor) Metropolitan Acoustics (Acoustical) Paul H. Yeomans (MEP) Molly Construction (Concrete Sub) Madden Electric (Electric Sub) Winslow Mechanical (Mechanical Sub) Oliver Sprinkler (Sprinkler Sub) E.J. Raith Mechanical (Plumbing Sub) EDA Roofing (Roofing Sub) 7

8 also in charge of all coordination for the project including reviewing submittals, requests for information, as well as addressing the Owner s concerns to the subcontractors. The type of contract was a Guaranteed Maximum Price (GMP) with a contingency. Cost Information The total project cost was originally $10.8 million. The contract for the site improvements for the 45 acre campus was approximately $3.1 million, while the cost of the New Middle School Building was approximately $7.7 million. Included in the contract was a contingency for approximately $300,000 to be used for either the Site Improvements or the New Middle School. Estimate Summary: On the following page is the estimate summary for the project. As you can see, the summary is broken down into the two major aspects of the project, the Site Improvements and the New Middle School Building. A three percent contingency was used for the project to absorb the cost of some unavoidable unknowns. Cash Flow Curve: After the estimate summary is the cash flow curve for the owner. The important issue to point out is the high spending in the beginning of the project. This is due to the Site Improvements that occurred during the first few months of the project. 8

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10 $1,500,000 Richard B. Fisher Middle School Cash Flow Schedule $1,250,000 $1,000,000 $750,000 $500,000 $250,000 $0 Monthly Cumulative Jun-01 Jul-01 Aug-01 Sep-01 Oct-01 Nov-01 Dec-01 Jan-02 Feb-02 Mar- 02 Apr-02 May- 02 Jun-02 Jul-02 Aug- 02 Sep-02 Oct-02 Nov- 02 Monthly Projected 278, ,071 1,275,58 1,382,55643, , ,62 639,33 640, , , , , , ,468306,972 14, Cumulative Project ed 278,517 1,0 19,58 2,295,17 3,677,72 4,321,4 5,088,7 5,983,3 6,622,6 7,263,4 7,804,16 8,219,4 8,586,4 9,047,8 9,757,09 10,477,510,78 4,5 10,79 9,410,79 9,4 $13,000,000 $12,000,000 $11,000,000 $10,000,000 $9,000,000 $8,000,000 $7,000,000 $6,000,000 $5,000,000 $4,000,000 $3,000,000 $2,000,000 $1,000,000 $0 10

11 Architecture The William Penn Charter campus has a unique and historical look. The designers and school desired the New Middle School to reflect the rest of the campus. More specifically, the Main Building on campus was used to help determine the look of the New Middle School. Therefore, the Middle School was built with exterior stone similar to that of the Main Building as well as a matching natural slate roof (see below for comparison). Inside the Middle School by the main entrance and in the commons area, are exposed heavy timber trusses giving a rustic feel. Wood flooring throughout the hallways is another natural feature. EXISTING MAIN BUIDLING COMPLETED MIDDLE SCHOOL BUILDING Structural The foundations of the building consist of concrete footings and piers in the basement level with a slab on grade. Concrete masonry units carry most of the load on the interior of the building as well as along the perimeter of the building. Loads are primarily transferred from the concrete metal deck to the steel joists to the concrete masonry units. In limited areas, W-shape beams and wood trusses take the load to steel columns or the concrete masonry units. 11

12 SUMMARY SCHEDULE 12

13 SITE RENOVAVTION PLANNING & SUBSURFACE CASE STUDY 13

14 Site Renovation Planning Site Construction In the beginning of the project the main focus was not on the new middle school building, but was on the site improvements that needed to be completed by the beginning of the school year. The site construction was spread out through much of the 45-acre campus. Due to the owner s needs, the entire site wasn t 100% accessible throughout the summer. The type of construction activities varied greatly which resulted in a wide variety of subcontractors on site at any particular time. The improvements that needed to be completed for the new school year were: Site preparation, sediment and erosion control Demolition of seven tennis courts and surrounding fencing Construction of seven new tennis courts and surrounding fencing Earthwork, including soil stripping and grading Tree removal throughout the entire campus Installation of new sanitary and storm sewer lines, including manholes and catch basins Installation of new electrical and telecommunications conduit and wiring, including manholes and site lighting fixtures Coordination with Public Gas Works of Philadelphia to install new gas service to the campus Removal of existing concrete paving, and asphalt paving New concrete paving and curbs New asphalt paving with all traffic and parking markings Furnishing and installation of new traffic signage Site fencing, bollards and chains in areas other than the tennis courts New playground area including safety surface and reinstallation of existing playground equipment 14

15 Two new athletic fields with new sod turf Erect a new tubular steel bus shelter All other landscaping and site furnishings including grass seeding, all plant material, benches, and football goal posts Site Access Restrictions Site access for the contractors was limited throughout the summer due to the needs of the owner. Coordination of all construction work in order to meet the owner s needs was the responsibility of the General Contractor. Site access issues that were addressed in the contract documents are the following: May 29, 2001 Athletic fields, tennis courts, and related areas available for contractor use. However, school is in session, and contraction shall not adversely affect school operations. June 11, 2001 School year completed. Remainder of site documented for construction, available for contractor. Must maintain access for faculty and staff to all facilities or provide reasonable alternative solution throughout all construction Coordinate with owner for site access and parking August 15, 2001 Athletic fields shall be substantially complete and available for school use. September 3, 2001 Remainder of Phase One, Site Improvements shall be substantially complete. Although the dates and items above reveal some key issues that need to addressed, they fail to point out the specifics each item. This is where communication between the owner and contractor becomes an important factor in the success of the project. Months before the project begins and before the contractor finalizes the project schedule and site plans, the project team needs to sit down and determine the special needs for the site. All major players in the project should participate, including the owner, architect, general 15

16 contractor, and related consultants and subcontractors. This can help alleviate conflicts from arising when the project is in full swing and delays constrict an already tight schedule. Some key items that were not in the documents that had a major impact on the schedule were items that the owner had brought up in the period right before construction began. These items should have been discussed upon awarding of the contract. The major item was that the removal of trees would be mostly limited to the north side of School House Lane due to graduation on June 9, See the figure on the right for the location of demolition. This was due to the fact of the objection by DEMO ALLOWED many students and their families of the removal of the large amounts of trees from the campus. The contractor had shown in the schedule that trees would be removed from the main part of campus starting on May 30, Due to the lack of communication, the contractor lost almost two weeks off the 14 week schedule for the site renovations. The contractor was responsible for allowing access to the site as needed by the owner throughout the summer. This includes access for faculty, staff, and the public. The major issue that the contractor needed to face was the summer camps that were offered by Penn Charter. The school had a Day Camp that ran from June 18, 2001 through August 3, Approximately five Sports Camps also went on throughout the same time periods, each lasting one week. This gave the contractor four weeks to complete all the work that needed to be constructed through the access and main entrance area. 16

17 The ongoing camps throughout the summer not only limited the access to the full site but it also created a few other logistics to deal with. One is the safety of the children attending the camps. The construction fencing and gates needed to be watched and kept closed to keep the children from wandering in curiously or cars from pulling into the construction site accidentally. There also needed to be an accessible route from building to FIELD HOUSE building for the day camp as well as staff of Penn Charter. The most noticeable problem is access for staff or campers to the Field House. As you can see in the figure above, the Field House is secluded away from the other buildings. The path from the other buildings goes right through the path of construction. Pre - Construction Planning Before any construction project has begun, there are a number of issues that need to be addressed by the project team. Preferably, these items should be looked at immediately after the contract is signed or even before the job has been awarded. Confronting these areas before the construction begins can alleviate headaches during the actual construction when addressing them at that time will undoubtedly cost time and money. It is in most cases the Construction Managers responsibility for raising the flag and bringing attention to these items. It is, however, important that all members of the project team contribute their thoughts on the issues. Some of these issues that should be addressed by the project team are listed below. These items are more specific towards this project, but on any project similar items will need to be attended to. Review project schedule and make sure that everyone agrees with the dates set forth by the contractor 17

18 Review the contract and make sure that all information is stated clearly and understood in case of a future disagreement Determine who is responsible for site security. Does the owner have their own security staff on-site to assist? What are the parking requirements? Is a temporary parking lot necessary? If so, how many spots are needed? Understand the permitting process in the area of the project and the amount of time needed to obtain the particular permits For sewer tie-ins, determine what municipalities need to be contacted. Provide a plan for road closures and obtain necessary permits Discuss with owner what entrance should primarily be used for deliveries and schedule work accordingly to make sure that site access is not blocked by construction activities Make sure that the neighbors are comfortable with the activities that will be going on throughout construction. The neighbors of the Penn Charter site live in costly homes. Therefore, it especially important to make sure that they are comfortable with all the heavy machinery to be used. In showing them that the school and the contractor care, there is a much NEIGHBORS INSPECTED smaller chance that there will be a complaint about the construction. In this case, Penn Charter decided to inspect the adjacent homes prior to construction so that if any damage were incurred to the homes it would be certified and covered under insurance. Need to locate safety signs throughout the campus, especially around the perimeter of the fencing to clearly show that there is no access to non-construction parties Determine location of and amount of temporary toilets 18

19 Determine long lead items and critical items to the schedule such as underground piping, manholes, and catch basins Locate existing utilities and distribute to all necessary site contractors to use in combination with existing contract drawings Make sure submittals for structures and piping are submitted and approved to allow for adequate time to produce and deliver to site Contract a consultant service for testing concrete pours and soil compaction rates Develop site specific safety plan including safety program explanations and emergency procedures Site Layout Plan One of the most important aspects of site renovation planning is developing and implementing the site layout plan. This plan helps to bring together the important issues raised by the three previous topics; Site Construction, Site Access Requirements, and Pre- Construction Planning. A site layout plan should be developed with input from all parties as discussed in the above sections. Not only showed a general site plan be developed, but a series of plans should be developed to account for the fact that the site is changing and demands for access and lay-down areas may change as well. Below is an example of a possible general site plan for the summer site construction. Site Access with wheel wash Construction fence Day Camp 19

20 The site plan above is only valid for a certain period of time during the summer construction period. Further in this report, in the 4D CAD & 4D CAD SITE PLANNING section, a schedule was combined with a 3D site plan consisting of the site renovations during the summer of A more detailed look at site layout planning will occur in that section. See below for a screenshot of the 3D CAD model. 20

21 Subsurface Case Study Soils Case Study Penn Charter Remediation Plan Subsurface issues can become a conflict on any construction project whether the contract is two million dollars or two-hundred million dollars. Improper subsurface exploration can lead to conflicts during construction as well as after the project is complete. Lawsuits can arise because of disagreements between the owner and the contractor about who is responsible for unexpected subsurface conditions. In this case there was no disagreement between the owner and the contractor, but an issue did arise concerning the soil that was excavated for the building s basement. BUILDING SITE The site of the New Middle School Building was previously occupied by seven tennis courts. The following results are from geotechnical services provided between October 30 th, 2000 and November 15 th, Underneath the tennis courts, there was Fill which was up to five-feet thick. Directly under the courts, there was a drainage course. This course, which was from two to three feet thick, consisted of dark gray and black fine to coarse with cinders. Below the Fill, there are Residual Soils. The density of the soils allowed for the buildings foundations to be built on the Residual Soils. Groundwater was not encountered in any of the test borings. Therefore, dewatering the site was not an issue for excavation. The Soils Report discussed above was provided to the contractors for bidding. The report was received by the contractors on March 5 th, 2001 and the bid proposal was due on March 9 th, In the month of May, a neighbor of the Penn Charter campus approached the school with a concern. His property is directly adjacent to the area of the site where the New Middle School was built. The concern was that the soil underneath the tennis courts was 21

22 contaminated. Trying to avoid any conflicts, Penn Charter volunteered to have the soils below the tennis courts tested for contamination, which was not a part of the initial site investigation. As it turned out, the Fill soil that was discussed above was contaminated with a high level of arsenic as found by the consulting geotechnical engineers. The level exceeded the Pennsylvania Department of Environmental Protection (PADEP) Statewide Health Standard for the Residential Direct Contact. This is not an uncommon situation in the historic area of Philadelphia. This meant that New Middle School portion of the project had successfully been delayed before the project even began. After the soil was found to be contaminated, a soil management plan was developed to protect construction workers and future occupants who will use the Middle School Building. The PADEP offers a release of liability for clean-up to owners who voluntarily investigate and remediate environmentally impacted properties in accordance with the Land Recycling and Environmental Remediation Standards Act ( Act 2 ). After the soil issue had been handled according to geotechnical engineer, they submitted a proposal to the PADEP to request a release from liability for the subject property. IMPERVIOUS COVER The millings from the tennis courts and the soils that were found to be contaminated were placed in a section of the site with none of the clean excavated soil. A geotechnical engineer observed the process to make sure that the appropriate procedures outlined in their Soil Management and Remediation Plan were followed. The contaminated soil needed to be covered by an impervious material until dispersal of the soil throughout the site, See figure at right. The soil and millings were used as base for a new parking lot on campus. When the time came, the soil was compacted, millings and stone base were spread out and the parking lot was paved with asphalt. This securely covered 22

23 the contaminated soil and helped to limit the cost impact of the delay. The excavation of the building was delayed approximately one month. The geotechnical engineer was contracted directly with Penn Charter to assist them in dealing with the contamination issue. On this job, the contractor had a three percent contingency in the budget. Since there was a Differing Site Conditions clause in the contract, Penn Charter decided to use the contingency to deal with the cost impact of the soil contamination. The cost impact included the added costs of handling the soil in a particular manner including the extra labor and impervious material as well as addressing the added cost to get the Middle School back on schedule to be complete for the school year. Handling the situation the way that the owner did probably prevented long term legal issues. It was an intelligent move to cooperate with the neighbor and show concern and express the obligation of being a considerate neighbor. Had the owner decided to ignore the neighbor who is a retired lawyer, a certain legal battle would have ensued. Every unique situation such as this can pose a threat to the success of a construction project. Handling the situation in sensible fashion most likely will help to alleviate the problem as quick as possible, but in construction there are never any guarantees. 23

24 Conclusions Site Renovation Planning Communication between Owner and Contractor should begin before the contract is signed Review proposed schedule with Owner before or immediately after the awarding of the contract to make sure that everyone agrees with the proposed dates and milestones Receive Owner input before developing a site utilization plan to avoid planning the site on multiple occasions Stay on top of issues such as long lead items and permits to avoid delays in a tight construction schedule with no room for float Develop a site layout plan with three main topics as contributors; Site construction, site access requirements, and pre-construction planning Subsurface Case Study Every subsurface conflict is unique and should be dealt with individually in a logical and timely manner Always involve experts who can help to remediate the issue the best way possible Deal with the issue, don t try to cover it up or avoid it. In the long run avoiding the issue will cost more money and take longer to fix as well as bring about possible legal actions. 24

25 4D CAD & 4D SITE PLANNING 25

26 4D CAD & 4D SITE PLANNING Introduction 4D CAD is combining a three dimensional computer aided design (CAD) with the fourth dimension, time. This serves as a tool for Construction Managers and Designers to help express the methods to achieve the final product. This is done by creating a model of a project in a computer drafting program. The model should be drawn so that logical parts of the project are grouped together to be linked with a construction activity. The construction activities are created using computer scheduling software and should be produced in a traditional bar chart fashion or critical path method (CPM). The schedule and 3D model can then be loaded into a 4D CAD application to be associated with one another. The model will visually change to rate of speed determined by the user, just as a video player. The computer programs used in this case were: AutoCAD D CAD Model Primavera Project Planner Scheduling Common Point 4D v1.2 4D CAD Generation Advantages 4D Model can be viewed from any angle and distance Using 4D technology has a number of advantages. Probably the most important benefit is the ability to communicate clearly to all the project players what the intent of the schedule sequence is and how the project is going to be feasibly constructed. The model should be designed well before construction begins to allow all the project players, including the client, designers and subcontractors, to identify any major construction issues that need to be dealt with. These items can be brought to the 26

27 attention of the Construction Manager before construction begins and it allows them time to develop a solution for the problem in order to prevent it from occurring. Some important issues may not be recognized because of the lack of analyzing the schedule by the project players. The 4D model gives the team the opportunity to visually see the activity without having to do much analysis. Once the 4D model is developed, the sequence may be altered easily and can allow the players to experiment with the project sequencing. This can help to determine space planning whether it is throughout a building or a project site. For the Penn Charter Project, 4D helped to develop a space plan for the site renovations. The major sequencing and space planning factors that were looked at for the Penn Charter Site Renovations were: Lay-down areas for utility piping and structures Day camp locations throughout the site Sequencing of construction activities Owner s needs for site access Verify agreement on completion dates for certain activities Another benefit to the Construction Manager is that project risk can be reduced by effectively communicating the project plan and having an agreed upon plan with the other members of the project team, especially the owner and the subcontractors. This assures that there is no ambiguity within the schedule and no questions about how the contractor will utilize the site during construction. Disadvantages Although 4D CAD has many advantages, there are a number of disadvantages that should be discussed. A few general disadvantages as well as some 4D site planning disadvantages are listed below: 27

28 Site planning is generally done in 2D CAD. The amount of labor that is put into a 3D CAD model compared to a 2D model is much more. In Common Point 2D drawings are not visible. Therefore, a 3D site model needed to be developed for the Penn Charter project. This demanded about two to three times the amount of labor compared to developing a 2D model. 4D models can become expensive and are usually outsourced by the Construction Manager to a technology company to develop the product Accomplishing the level of detail desired can be an issue. For the Penn Charter project the site spans 45 acres. It can be quite difficult to be able to see everything at once on the screen. Much maneuvering is needed to be able to understand what is occurring throughout the site. Costs Autodesk VIZ 4 - $1705 AutoCAD $3395 Common Point 4D v1.2 - $5900 Labor variable Source: Autodesk Corporation Source: Autodesk Corporation Source: Common Point Technologies The general costs for the 4D CAD application are listed above. The first three costs are the costs for the software and licenses. These could be placed in the contractor s company overhead costs or be charged to the particular projects that utilize the software. The labor would obviously vary depending on the complexity of the project and the skill of the model generator. For this project I would estimate that an experienced computer drafter would be able to complete the 4D model in one work week. I would also estimate that it would take another work week to develop the plan for the drafter to draw. These costs would be approximately $1500 per week for one person s time. Therefore, my estimate for labor on this project is approximately $

29 The below cost is assuming that the only project during that year that the contractor used 4D CAD on is the Penn Charter project. Approximate Total Cost for Penn Charter Site Planning: $14,000 Assuming that one other project used 4D CAD throughout that year and that it helped to absorb the cost of the software, the revised cost would be $8500. Penn Charter Site Renovations Schedule See the following two pages for the schedule used to develop the 4D CAD model 29

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32 The above schedule was organized using the requirements set forth by the owner while trying to maintain an even amount of crews for the key subcontractors. The schedule when used in 4D allows the scheduler to see where the crews are working throughout the schedule. It helps to recognize whether too many or too few crews have been scheduled. This lets the contractor schedule the crews more efficiently to keep the work flow steady. From the schedule above, the new completion date for the summer construction is August 15, There is enough float in the schedule for unknowns such as subsurface issues and inclement weather. This is compared to August 24, 2001 as originally scheduled. The actual completion date went passed the deadline of September 3, This occurred even though for most of the summer crews worked 6 days a week. The main reasons the project did not proceed as scheduled was the following: Subcontractors not producing enough manpower Lack of communication between the owner and contractor in pre-construction stage Subcontractor did not expedite site permit immediately Submittals were sent in for approval late causing a delay in the manufacturing of the underground piping and structures Conclusions 4D CAD allows contractors to efficiently organize a large site while balancing subcontractor s crews 4D CAD can communicate the plan to everyone on the project team effectively and can help to alleviate costly misunderstandings in the field 4D CAD is not recommended for the Site Improvements at Penn Charter because of the size of the project. The same results on a smaller scaled project can be achieved through open communication between the project team and a well thought out plan that everyone can understand and agree to. 32

33 STRUCTURAL PROPOSAL & ANALYSIS 33

34 Structural Proposal Introduction The structural system that was used in the middle school was load bearing concrete masonry units with steel joists bearing on them. These load-bearing walls are located in the basement, on the first floor and on the second floor. There was a minimal amount of structural steel framing used on the project. On the top of the building there are wood trusses used to MASONS INSTALLING frame the roof. The basement foundation consists of EXTERIOR BASEMENT BLOCK concrete spread footings under columns and continuous spread footings under the CMU walls. The basement floor is a slab on grade and the rest of the floors are slab on metal deck. I decided to look into using hollow core concrete planks with a 2 topping slab instead of open-web steel joists with 4 concrete on metal deck. This system will be explained further in the next section. The actual system s sequencing followed this pattern repeated from the basement to the top of the second floor: Install concrete masonry units Install bond beam Weld bearing plate and set steel joists Lay concrete decking Pour concrete slab on deck SEUQENCE GAP When looking at the schedule by trades you can easily notice the problem caused by the original system, as seen in the figure to the right. There 34

35 are time gaps between trade s activities that they are performing on the job. The masons, steel erectors, and concrete contractor were the most effected by the system. Some of the issues were: Masons needed to complete their work before the steel trusses could be erected During erection of the steel trusses there was no masonry work able to be performed Once steel decking was completed and concrete poured, the masons could begin on the next floor Steel erectors and concrete contractors were then waiting for the masons to complete the block work up to the next floor level By using the hollow core plank system, sequencing issues should be alleviated by a certain degree. But before looking at the sequencing solution a comparison between the two systems should be discussed. System Comparison As built, the floor framing at the New Middle School Building is open-web steel joists at 3 on center with metal deck and a 4 concrete slab. The steel joists vary in depth from 10 to 26 depending on the span and are supported by concrete masonry units (CMU), which range in thickness from 12 at the basement to 8 for the first floor and second floors. The hollow core concrete plank system is efficient because it offers cost and time savings benefits. The 2 topping slab for both floors can be poured at the same time to allow the pump truck to remain on-site until complete. Hollow core plank comes in 4 widths, so for every four steel joists that were needed at the New Middle School only 3 planks would be required. Both systems require a crane on-site to lift to the installation location. The planks are cast in controlled environment minimizing the possibility for errors in the field. Since, the planks are pre-cast this also allows for a faster erection time. One 35

36 problem with the joists is making sure that the steel erector is not mixing up the different types of joists. On this project there were nine different types of joists installed. Sorting time can be significant and time to check that the joists are being installed in the right location. Pre-cast also means that the members are pre-stressed so the planks can carry have a greater load capacity than other structural members of an equivalent depth. For the new middle school the maximum floor depth with steel joists is 30, but a floor depth of 14 can be achieved with the hollow core plank and a 2 topping slab. This allows for piping and ductwork to easily be placed in the plenum space without having to run through the open-web joists. A concrete system offers many advantages over a steel system. Concrete is inherently fire and sound proof. The original floor system has a 0 hour fire rating. Therefore, the fireproofing will not make a difference in price or schedule. The sound resistance will allow the mechanical equipment in the basement to operate normally without transferring noise to the first floor. Deeper, heavier and more costly joists are often required not for strength, but to reduce the floor vibrations. Since a steel joist system is very lightweight, there is a tendency for the floor to vibrate as people walk across it. With a concrete system, vibration is not of concern. Metal deck has to be welded to the steel joists every few inches. Though a single tack weld may not be the difficult process, the job becomes quite extension when the total number of joists and the total joist span is considered. Hollow core plank does not require a metal deck; a topping slab can be poured directly on the plank if a smooth floor surface is required. In this case, the topping slab is necessary due to the wood flooring that exists throughout the building. The topping slab should limit the amount of selfleveling or flash patching that the flooring contractor would use. 36

37 Both systems work well with a CMU bearing wall. The steel joists must be welded to a steel plate which is embedded in the bond beam in the wall, while the concrete plank is connected to the wall with reinforcing bar and grout. Hollow core plank is not appropriate for all buildings, due to span limitations, but the plank system would work well at the New Middle School. The maximum span is 32 which is easily reached with hollow core plank, so this would be an excellent consideration. A summary of the advantages are listed below: Steel Joists Hollow Core Plank 10"-26" depth 12" 3' O.C. 4' O.C. Extensive Fireproofing Inherently Fireproof Vibration Considerations No Vibration Acoustical Issues Sound Attenuation Bridging Needed to Stabilize Laterally Stable Tack Welded to Deck No Metal Deck Welded to Steel Plate at Bearing Reinforcing at Connection to Wall 37

38 Structural Analysis Design Criteria The structure has been designed in accordance with the Philadelphia Building Code, updated 3/2000. Use Group: Main part of building, E Educational; Commons area, A-3 Assembly Construction Type: 2C Noncombustible The design loads used are given below in the following tables: LIVE LOAD DESIGN SCHEDULE Area Load (PSF) 1st and 2nd Floor 60 1st Floor Corridor 100 2nd Floor Corridor 80 Collateral 12 Ceiling 3 TOTAL LIVE LOAD Area Load (PSF) 1st Floor 75 1st Floor Corridor 115 2nd Floor 75 2nd Floor Corridor 95 Plank Selection For this analysis Nitterhouse Concrete Products are used. Using the load tables provided by Nitterhouse the maximum length for each loading situation needs to be determined (corridor, floor load). 38

39 For the 1 st and 2 nd floor the maximum span is 32 feet. Using the load charts and the total live load of 75 PSF, it is determined that the 8 x 4 plank can be used. This is a hollowcore concrete plank with a 2 topping slab. 75 PSF < 77 PSF 115 PSF < 235 PSF The corridor load is a maximum of 115 PSF. Using the same type of plank and looking at the loading chart, the loading meets the requirements. This is using the maximum length of the plank in the corridors of 22 feet. Pre-stressed Concrete Plank - J917 Length 32' 22' Allowable load 77 PSF 235 PSF Live load 75 PSF 115 PSF Check OK OK The pre-cast planks will bear on the CMU walls on the interior and exterior. The sections below show the details for the pre-cast wall system. The system is the same as what is originally designed except for the pre-cast is substituted for steel joists and slab on metal deck. 39

40 PRECAST DIRECTIONAL LAYOUT 1 st & 2 nd FLOOR COMMONS AREA CAST IN PLACE CONCRETE NO STRUCTURAL CHANGES STR STR PRECAST DIRECTION EXTERIOR WALL DETAIL FOR PRECAST 40

41 INTERIOR WALL DETAIL FOR PRECAST Schedule Analysis When looking at the hollow plank system, it is obvious that it can solve some of the sequencing problems, but it can t solve all sequencing problems. The main issue is that without careful scheduling the masons will still have a gap in the time sequence Schedule finishes 22 days early Leaves time for punch-list to be completed before teachers and staff move into the building in the middle of August This alleviates the headache of the contractor trying to complete punch-list items while there is occupancy and more punch-list items are being created by the occupants. Building will be weather tight before the start of the winter season See the next page for the construction schedule for the pre-cast and topping slab. 41

42 1 ST & 2 ND FLOOR SEQUENCE ROOF ENCLOSED BY OCTOBER 18 TH 42

43 Cost Analysis Original system including Philadelphia location factor 43

44 Pre-cast system including topping slab Cost Savings: $ 22,183 Conclusions Pre-cast is simpler system for field construction Produces minor cost savings Shortens schedule Doesn t solve sequencing problems 44

45 CONCLUSIONS & RECOMMENDATIONS 45

46 Conclusions Recommendations Site planning deals with many different aspects of construction and collaboration. When developing a plan three factors need to be considered in detail: Site construction Site access requirements Pre-construction planning Subsurface issues should be dealt with immediately. Avoiding the problem could lead to larger problems down the road, financially and legally. 4D CAD is an effective way to organize multiple site issues and communicate a plan to others on a project team. Smaller projects usually do not have a budget for 4D CAD, which can become costly. These projects should focus on other ways to plan and communicate the important issues before they become costly and unproductive issues. Therefore, 4D CAD on the Penn Charter project is not feasible because of the high cost of the software and the time that it consumes to develop the model. Pre-cast plank systems create an easy erection phase for the floor systems. Fast and easy to install, pre-cast planks may save the client money. Due to the fact of the quickness and ease of construction, the block and plank system should be used over the block, joists, and slab on metal deck system. 46