Creative Construction Conference 2015 The U.S. Army Corp of Engineers traditional design review vs. A BIM review: A case study Miranda Griffin, Scott W. Kramer, Ph.D.* 118 M. Miller Gorrie Center, Auburn University, Auburn Alabama 36849 USA Abstract In the current turbulent funding environment, it is important that the U.S. Government spends every construction dollar wisely and does everything possible to get the best rate of return on those dollars. It is essential that cost control is managed during the design and construction phases of a project. The United States Army Corps of Engineers (USACE) recognized that having construction documents that are easily understood, free of design errors and omissions and met the needs of the customer saved time and money during the construction phase of the project. Because of this realization, USACE developed a formal design review process known as Bidability, Constructability, Operability and Environmental (BCOE) reviews. The BCOE review process has three goals (1) Identify problems related to errors, omissions, and inconsistencies that would keep contractors from bidding on a project; (2) Identify inappropriate construction methods and materials that would increase construction cost; (3) Identify building systems and components that would result in buildings that are difficult to maintain and operate. This case study was performed to analyze the effects of the Bidability, Constructability, Operability, and Environmental (BCOE) review process and Building Information Modeling (BIM) on a complex construction project managed by Mobile District, USACE. It was determined that performing the BCOE review ensures code compliance and customer requirements but BIM modeling easily identified design errors and conflicts. Keywords: BIM; Constructability; Design Errors; Project Delivery 1. Introduction U.S. Army Corp of Engineers BCOE Review Process The United States Army Corps of Engineers is mandated to perform a bidability, constructability, operability and environmental (BCOE) review for all construction projects [1]. Constructability and bidability are defined as the ease with which a designed project can be built and the ease with which the contract documents can be understood, bid, administered and executed. Operability is defined as the ease with which a project can be operated and maintained. An environmental review is performed to assure the protection of land, water, animals, plants, air and other natural resources from the effects of construction as stated in the environmental assessment. Also, the operation of the constructed project must protect the environment as stated in the environmental assessment. The purpose of the BCOE process is ensure efficient construction that is environmentally sound, to minimize cost and time growth, to avoid unnecessary changes and claims, as well as to ensure safe, efficient operations by the user [1]. The assigned reviewers are required to enter their review comments into the Automated Review Management System (ARMS). The PM collates the comments and sends them to the responsible design Architect Engineer (AE) firm. The AE firms provides copies of the comments to their sub architect engineer firms- electrical, mechanical, structural, and specialty systems. The AE firm and the sub architect engineer firms reviews the comments presented Tel.: +1-334-844-4518; fax: +1-334-844-5386. kramesw@auburn.edu 506
by the assigned reviewers and prepares a response for each comment. The PM coordinates a meeting to be attended by the assigned reviewers, AE firm and sub architect engineer firm, and project management personnel. During the meeting, agreement is reached between the AE firm and the person who made the comment of the action required in response to each comment. Either the AE firm clarifies that the design as presented is correct or the AE agrees that a change should be made to the design documents. This process continues until the final design has been corrected per the final design review meeting. After the approved final design is presented to the PM from the AE firm, the contract documents are put out for the construction contractors to bid. 2. Background Information for the Case Study The 7 th Special Forces, Phase I Military Construction project is a project that is part of the Base Realignment and Closure Program (BRAC). The project involves the construction of the entire compound on a virgin site for the Army s 7 th Special Forces Group. As part of the BRAC program, the 7 th Special Forces Group was slated to move their function to Eglin Air Force Base, which houses many other Special Forces group, in an effort to maximize joint training of all the Special Forces components. Phase I includes the construction of eight facilities, two elevated water towers, an underground communications and power distribution system, asphalt roads, a new intersection at Highway 85 and the clearing of 350 acres. Of the eight facilities constructed, four were designed by one Architect Engineer (AE) firm coded AE1. The remaining four facilities were designed by another AE firm coded AE2. The facilities designed by AE1 were four different facilities: Group Headquarters (), Group Support Battalion (), Dining Facility () and Combat Training Readiness Facility (). The four facilities designed by AE2 were four Battalion Headquarters (Batt HQ) that were exactly the same, so AE2 was responsible for only one design. The site work design was performed by one sub-architect engineer firm for the entire project. AE1 and AE2 worked with this sub-architect engineer firm to design the layout of the compound and to design all of the exterior systems to the facilities like the communications, power, storm water, and roadways. Each of the facilities has multiple electrical and mechanical systems within them. Each facility has a fire protection system, Heating, Ventilation Air and Conditioning system, Access Control system, and plumbing. The Batt HQ,, and have weapons vaults and a Secure Compartmentalized Information Facility (SCIF). The Dining Facility is a complex design of its own because a food kitchen consultant must work with the AE to coordinate the mechanical systems within the food kitchen equipment with the mechanical systems of the building. AE1 decided of his own accord to use BIM for each of the facilities that were his design responsibility. However, he was not able to use BIM for the other disciplines, electrical, mechanical, structural, because the sub architect firms did not have the BIM software and were not trained on how to use it (AE1, personal communication, November 17, 2012). AE2 did not use BIM for any portion of his design. The design concept of Phase I began in 2007. The average time from design concept to actual construction completion for the United States Corps of Engineers is five years. Because the project was a BRAC project, there was a definite completion date of September 15, 2011. However, there was an uncertainty of when the actual construction could begin because the site selection was held up in an environmental assessment with another project that was being challenged by the community. The AE firms were instructed to design the facilities without having a firm site selection. The Corps of Engineers continued the normal BCOE process and completed the design of each facility. When the site selection was finally completed the sub AE firm worked with each of the AE firms to finalize the layout of the compound and the location of each facility within the compound. The construction contract was awarded in January, 2009. The contract amount was $154,683,000. As stated earlier, the contract had a congressionally set completion date of September 15, 2011 which gave the contractor a construction time of two years and nine months to build eight facilities plus the power, communications and site infrastructure. Recognizing that the construction time had been significantly reduced, Mobile District, USACE decided to implement BIM during the construction phase. Because of funding, the BIM model of the facilities and the infrastructure was delayed at the onset of construction by four months. When the modeler was able to start the BIM models of the buildings, requests for information (RFI s) were generated to address the design errors that were detected by the BIM software. 507
3. Rational for the Case Study Mobile District, USACE has a robust military construction program. Each year billions of dollars are used to construct facilities for their military customers. Because of the national budget crisis, funding for military projects is highly competitive and the customers want the greatest return on their investment through cost effective design and construction processes. Controlling the time and cost growth of the project during the construction phase is very important to having a successful project. For many years, USACE has used the BCOE review process to eliminate as many design omissions and errors as possible during the design phase. Using the traditional BCOE approach, the designers, reviewers and builder are limited to using the two dimensional (2-D) drawings/views [2]. Using BIM, the designer creates an accurate geometric representation of the facility that is data-rich and facilitates collaboration among the designer and the reviewers. The BIM model is a common model of the facility that each person uses to either create their portion of the design or to use the software to analyze the design. Once the final BIM model is signed off on, the design is locked and can be transferred to the constructors for the construction phase. Since the BIM model can be used for virtual visualization, the constructors can use it to plan the most time efficient construction schedule for the project. The traditional BCOE review process stops at the design phase and is of no benefit to the constructors. BIM has the benefit of being used to same time during the design and the construction phase. Saving time and cost during the life-cycle of the project is of major importance to UASCE and our customers. Because using construction funding wisely is crucial as funding for construction projects becomes more competitive, USACE can show their customers that we are taking a proactive approach to finding effective management of this problem by investigating how BIM and other tools can be used to improve our construction process. 4. Data & Analysis Table 1 Facility BCOE REVIEW COMMENTS BY BUILDING & DISCIPLINE 35% REVIEW 65% REVIEW FINAL REVIEW BATT HQ Mech 9 10 16 10 13 26 19 6 16 14 25 3 11 1 19 Architect 103 37 68 23 104 101 23 44 68 126 131 11 46 34 126 Elect 59 12 50 25 59 138 18 76 50 94 184 14 49 46 79 Plumbing 3 0 3 5 3 2 0 9 3 4 4 0 0 6 3 Structural 7 14 9 29 15 22 14 19 9 49 7 0 15 6 18 Fire Prot 13 15 14 13 23 21 0 16 14 35 3 18 0 2 25 Total 194 88 160 105 217 310 74 170 160 322 354 46 121 95 270 Table 1 depicts the number of comments by trade and by facility given by the reviewers during the three phases of the BCOE review process. As stated earlier in this paper, the civil/site work design was not completed until it was time to advertise the project for bidding and did not have a BCOE process. There are no comments for the civil/ site work design. The number of comments given for the and Batt HQ from the 35% review to the final design remained almost the same indicating that either the original comments revised the design in such a way that each time the design was presented it appeared like it was new design, the design was not back checked per the comment or the designer did not sufficiently correct the design per the original comment. If this facility were modeled during the design phase using BIM, the designer could have made the change per the comment in real time and collaborated in real time for accuracy and clarity to resolve the review comment. The steadiness of comments for these two facilities, also, was an indication that the documents for these two facilities would create the greatest difficulty for the contractor to understand during the construction phase. This fact is shown in Table 2 by the number of RFI s that were generated using BIM. Both the and Batt HQ have the two highest numbers of RFI s. The disciplines that have the three highest numbers of RFI s are architecture, structural and electrical. Two of these disciplines had the highest number of comments during the BCOE review. This indicates that the traditional BCOE process did not resolve whatever the issues were for these portions of the design. Whatever the errors were, the BIM modeler found them and quickly identified them for correction. If the error was identified early enough in the 508 BATT HQ BATT HQ
construction phase and no additional materials were needed, no additional cost was involved with making the change. If the response to the RFI, required the re-order for material that was either already onsite but not installed, the Government was assessed a cost for re-procurement. In a worse case, material actually installed, the Government was assessed a cost for re-procurement, re-work and overhead for time impacts. The installation of the structural steel and the electrical conduit for the security system for the first Battalion Headquarter facility was a worse case situation. The responses to the RFI s for the structural steel installation of the Battalion Headquarters would result in a new conflict and a new RFI to describe the new conflict. If the designer was using BIM, the conflict could have been resolved quicker and without creating a new conflict because the clash detection ability of the software would have identified any conflicts when the object was moved. The BIM modeler could have identified what correction was needed but in the contract arrangement the modeler was not to perform any design, only identify where the conflicts were in the design. Table 2 Request for Information (RFI s) by Building & Comment Facility BATT INFRASTRUCTURE TOTAL HQ Architect 105 61 91 71 177 6 511 Structural 40 14 14 25 457 0 550 50% of these are resubmissions. Mech 32 15 15 25 65 1 153 Elect 100 70 70 75 123 32 470 Fire Prot 11 7 7 11 12 0 48 Plumbing 18 10 10 26 27 1 92 Concrete 1 2 2 1 7 4 17 Civil/Site 0 0 0 0 0 25 25 Total 307 179 209 234 868 69 1866 Table 3 shows which portion of the design had the most changes and the cost for those changes. The and the Dining Facility had the least number of changes and the lowest cost for changes. These two facilities also, had the two lowest numbers of comments during the BCOE review process. The two things that the two facilities did not have that the others did have are a weapons vault and a SCIF. A SCIF requires careful coordination between the electrical, mechanical, structural, and architectural designers. The structural steel for the walls of a SCIF has a precise layout requirement that must be met for it to be certified for its intended use. The steel design sets the precedence for how the remaining items are designed for the SCIF. An error in the steel design starts a domino effect on the remaining design of the SCIF. The numerous structural steel errors of the Battalion Headquarter facility caused a change order late in the construction phase that caused an expensive change for the electrical installation. The electrical conduits were installed but the design correction required them to be removed and re-installed. Table 3 Facility # of Changes by Facility & BATT. HQ Infrastruc. $ Value of Changes by Facility & BATT HQ Infrastruc. Mech 4 4 4 5 20 0 51,763 52,892 46,529 74,458 292,766 0 Architect 6 5 2 6 33 0 1,11,196 353,407 8,835 78,772 685,180 47,221 Elect 9 4 2 2 14 6 876,704 357,271 73,213 73,213 6,554,776 732,519 Plumbing 2 0 0 3 0 4 58,468 0 0 72,189 0 205,348 Structural 8 2 4 0 19 0 380,235 38,519 3,158 0 685,180 0 Fire Prot 4 1 0 1 1 0 169,024 53,258 0 58,526 291,277 0 Concrete 0 0 0 0 1 1 0 0 0 0 20,836 23,823 Civil/Site 1 0 0 0 1 28-93,938 0 0 0 40,879 9,574,666 Total 34 16 12 17 89 39 1,553,452 855,347 131,735 357,158 8,570,894 10,794,577 509
The portion of the design that had the second highest number of changes but the highest cost was the infrastructure. The infrastructure design was completed late in the design phase and did not go through the formal BCOE process. However, in this instance the BCOE review process would not have helped to eliminate most of the changes that occurred on the infrastructure because the changes were related to environmental permitting. The Florida Northwest Florida Water Management (NWFWM) department mandated most of the changes for the infrastructure design. The changes were related to meeting their standards for establishing stabilized site after all of the trees were removed from the 350 acres. The civil/site work designer provided a design that was easily constructible but NWFWM had strict standards of how they wanted the civil/site work designed. NWFWM issues the permit for the project and is the Authority Having Jurisdiction (AHJ) so the Government and the civil/site work designer were at their mercy. Two of the 39 changes on the infrastructure design were due to a different site condition. There was clay discovered in areas of the site that were not revealed by the borings. There were six changes on the electrical design for the infrastructure that were due to conflicts with the storm water piping. The BIM modeler did not model the infrastructure but if the model was performed it would have revealed the conflict between the electrical conduits and the storm water piping. The $732,519 that was spent on the electrical changes could have been saved. The BIM model would not have helped save the cost due to NWFWM requirements though the BIM software has the ability to verify code compliance. BIM could have been used to show that the civil/site work designed met those code requirements. In this instance the opinion of the NWFWM would override, regardless. Table 4 - Constructability Analysis Building # of Issues Identified Trade Percentage BHQ 90 Framing 58% 14 HVAC 17% 56 Fire Protect 2% 51 Steel 19% 11 Concrete 3% TOTAL 222 All other trades 1% (Information Courtesy of Thompson Engineering, Mobile, AL) The information shown in Table 4 shows the number of issues identified in each facility by the BIM software and the percentage of those items by trade. Per the constructability analysis report, the cost savings that was realized during the construction phase of the project was $3,064,000 to $6,432,000. (Thompson Engineering, personal communication, November 21, 2012) The cost savings are based upon the construction time saved and the labor that was saved by not having to do re-work. Constructability Report showing Clash Detection. Cut view from design document indicating conflict. Figure 1 (Courtesy of Thompson Engineering, Mobile, AL) 510
The BIM software indicates the conflict by clash detection and provides a report of the issue as shown in Figure 1. These reports can be used during the design phase to correct the design or during the construction phase to assist the constructor. The constructability reports were used by the construction contractor on the Phase I project to save time during the construction. In Figure 1, the conflict indicated is between the HVAC ductwork and structural steel members. This same report was used to show the HVAC ductwork was entering the electrical room in a location that would violate the National Electrical Code. The traditional BCOE review process did not reveal these design errors. 5. Conclusion On the 7 th Special Forces Phase I project, the RFI s that were saved by the BCOE review process was mainly code compliance and customer specific requirements. Very few of the comments revealed any design conflicts. Both code compliance and customer satisfaction items are very important and do result in time and cost savings. The elimination of conflicts and design omissions in the construction documents results in cost savings and customer satisfaction through the construction of a facility that is constructible, operable and maintainable. The design errors were discovered through the use of BIM. Although the BIM model was delayed by four months from the construction start, the modeler was able to build the models of the facilities in time to report the many conflicts between the structural steel and other systems in time to minimize construction delays. If BIM had been used during the design phase, the number of RFI s eliminated during the design phase would have virtually erased the RFI s that were generated during construction phase. The BCOE review process alone did not eliminate the RFI s that were generated from design conflicts and omissions. The cost savings realized of using BIM for the design review would easily have been approximately $10,798,067 which is the cost of the mechanical, electrical, architectural and structural changes. The clash detection software of the BIM models of the facilities identified design conflicts between the various systems that were not identified through the traditional BCOE review process. All design conflicts will not be discovered or eliminated by either the BCOE review process or BIM because there is a human factor involved with each. However, using the two processes together may eliminate the majority of the design conflicts. References [1] East, W., Roessler, T., Lustig, M., (1995) Improving The Design-Review Process: The Reviewer s Assistant, Journal of Computing In Civil Engineering, 229-235. [2] Korman, T., Simonian, L., Spiedel,E., (2008), Using Building Information Modeling to Improve the Mechanical, Electrical, and Plumbing Coordination Process for Buildings, American Society of Civil Engineers. 511