1、Michelle L Swanson is a Mechanical Engineer and Project Manager with The RMH Group in Lakewood, CO.Design-Build Successes and Challenges for the Byron G. Rogers Federal Office Building Michelle L. Swanson, PE ASHRAE Member ABSTRACT The design-build construction method presents opportunities and chal
2、lenges to all the groups involved in a construction project. This paper will explore how the mechanical and electrical designers and contractors addressed these opportunities and challenges for the recent Byron G. Rogers Federal Office Building modernization project in downtown Denver, Colorado. The
3、 project involved approximately 500,000 square feet of renovation and deep energy retrofit in an existing high-rise building which is anticipated to to be added to the National Register of Historic Places in the future. The project team was challenged to rebuild the entire mechanical/electrical infr
4、astructure while maintaining the historic exterior faade and keeping the adjoining courthouse operational which has mechanical/electrical systems fed from the office building. Because the building provides office space for multiple government agencies, the design-build team was tasked with coordinat
5、ing the differing agencies requirements and schedules to complete their spaces. The building owner, the General Services Administration, had very aggressive energy-saving goals; one of these goals was for the projects lighting to be 100% LEDs, which presented a challenge due to the lack of commercia
6、lly available LED fixtures in 2010. The project team consisted of a general contractor, who held the contracts for the architectural and structural designers and for the mechanical and electrical contractors. The mechanical and electrical contractors held the contracts with the respective mechanical
7、 and electrical designers. INTRODUCTION Located in downtown Denver, Colorado, the 18-story, 494,000-square-foot (45,894-square meters) office building is home to more than 20 federal agencies/sub-agencies and serves as an important example of 1960s-era federal architecture. Due to its age and condit
8、ion, the building was selected to receive funding for a complete remodel through the 2009 American Reinvestment and Recovery Act (ARRA). Because the General Service Administration (GSA) received additional ARRA funding strictly to incorporate emerging energy efficiency technologies such as LED light
9、ing into the design, the GSA established aggressive sustainability targets well beyond federal requirements for the project. The challenge of meeting these sustainability targets was complicated by having to preserve the architectural elements and characteristics of the era in which this historic bu
10、ilding was built. The GSA selected design-build as the project delivery method. Design-build is a project delivery method in which both design and construction services are simultaneously contracted to Figure 1 The 18-story office building is located in downtown, Denver, Colorado. a single entity. T
11、his is in contrast to the more traditional design-bid-build project delivery method in which the project owner contracts with separate entities for the design and construction portions of a project; the construction portion of a design-bid-build project is usually bid to a construction entity after
12、the design has been completed. Various metrics and studies have shown that design-build delivery can be completed with decreased costs and in a shorter time frame than with design-bid-build project delivery. Both delivery methods can result in quality projects; building owners needs to weigh differe
13、nt variables when determining which project delivery methods are most appropriate for their individual projects. THE PROCESS In 2009, the GSA released a Request for Qualifications (RFQ) document for design-build teams to renovate the office building. At the time, the team (which would ultimately be
14、selected for the project) was led by a general contractor with architectural, structural, historic preservation, mechanical, plumbing and electrical design partners. The team presented an innovative overall design solution to assist the GSA in meeting federal sustainability mandates and delivering a
15、n energy efficient and inviting place to work in the GSA property portfolio. After being selected for the renovation project, the team worked with the GSA to tailor its design-bid-build standards to accommodate design-build project delivery. Although some standards were easily modified, others were
16、required by the GSA to remain the same, which presented challenges to the project team. As the process progressed, the design-build team worked with the GSA and multiple tenant agencies to work through numerous issues including meeting ARRA funding regulations for the project. Complicating the matte
17、r was the fact that some federal agencies and sub-agencies were not planning to return to the building after the renovation. Understanding and documenting all parties needs and desires for the project presented an interesting and sometimes overwhelming task. The project team spent time educating the
18、 groups that the project would not be hard bid, which was different from what most of the participating groups had experienced before. Although the project primarily followed a design-build structure, some changes had to be made to allow for some products and subcontractors to be hard bid. PROJECT C
19、HALLENGES Like any construction project, this one was not free from challenges; however, the team worked through many project issues to deliver a successful project. The way the mechanical and electrical contractors were brought onto the project presented a major challenge for the design team. Durin
20、g the schematic design phase of the project, the general contractor selected the mechanical and electrical contractors from the trade partners that were assisting with the budgeting of the renovation during the proposal phase. The mechanical and electrical contractor pricing was based on the proposa
21、l-level narrative and the very few drawings developed during the proposal phase not on the current, continuously developing design drawings. The mechanical and electrical contractors submitted a hard-bid number to the general contractor for every deviation from the proposal-level narrative; however,
22、 the overall project budget could not change. Because of this scenario, the engineers were required to find other items to value engineer to pay for the changes. For example, as the design evolved, we discovered a need for larger domestic water heaters than were originally planned. The mechanical en
23、gineer had to justify the increased water heater size to the mechanical contractor, and then the mechanical contractor had to attempt to be compensated for the change from the general contractor. The rush to develop pricing without proper documentation created situations in which the design team had
24、 to spend extra time justifying a good design practice vs. designing to the absolute minimum. Another challenge was the contract structure. The mechanical and electrical engineers were contracted to each disciplines respective contractor, which blurred lines of communication and made team coordinati
25、on difficult. For example, coordination between the architectural and engineering teams was not as open and fluid as the architects would have preferred. The contractors wanted to be present at all coordination meetings, which sometimes limited the creativity of the design team because the contracto
26、rs were so focused on budget. The GSA also presented challenges to the design-build team. The GSA issued the RFQ with a list of tenants and a well-planned stacking diagram indicating how those tenants would fit into the 18 stories of the building. As the project progressed to design, The GSA and the
27、 team discovered that several of the prospective tenants were not happy with the current building or the proposed open-office design. As a result, significant time was devoted by both the design-build team and the GSA to convince these tenants to return or find new tenants when some decided to go el
28、sewhere. The design-build team was extremely committed to the overall success of the project and assisted the GSA, as needed, to attract tenants for the building, primarily by giving presentations and assisting with marketing materials about the building. Because the office building modernization wa
29、s the first design-build project for this GSA leadership team, the design-build team allocated a significant amount of time educating the GSA leadership team and trying to meet the requirements of a design-bid-build project in a design-build environment. PROJECT SUCCESSES The project was a success o
30、n many levels. In addition to the project being completed on time and within budget, the tenants were pleased with the final design and functionality. Some tenants experienced initial difficulties with the newer systems in the building such as the destination dispatch elevators that require riders t
31、o select their desired floor before entering the cab. However, after a brief adjustment period, they came to understand the efficiencies of these new systems. The destination dispatch system is energy- and time-efficient because it directs riders to a particular cab based on destination. The lightin
32、g vacancy sensors also presented a learning curve for the tenants since an occupant needs to turn on the lights when entering the space, but the lights are automatically turned off when motion is not detected. The project was also successful in reducing building energy usage. An initial project requ
33、irement was for the building to achieve a 30% improvement on energy use over ASHRAE 90.1 2007; the project team easily surpassed this goal. Pending the energy model acceptance for LEED documentation and the actual operation data comparison, the project is anticipated to achieve approximately 35% bet
34、ter energy efficiency than ASHRAE 90.1 2007. The GSA also had a goal for the building to be 100% lit via LED lighting, which was difficult in 2010 because many commercial lighting manufacturers were not making a wide range of office lighting LED products. To overcome this challenge, the design-build
35、 team (along with the GSA) initiated a design competition among lighting manufacturers for the buildings general office lighting. The team asked manufacturers to create a prototype and installed a mock-up in the building to allow the design-build team and the GSA to evaluate each fixture from a perf
36、ormance and maintenance standpoint. After the comparisons were made, an LED lighting manufacturer was selected to produce the buildings general office lighting. Some of the manufacturers that were not selected used prototypes designed for the competition into production for other customers, which fu
37、rther propelled the overall LED lighting market. Figure 2 features a portion of the evaluation matrix that was created to compare the LED products. Figure 2 Lighting mock-up comparison spreadsheet From a design-build perspective, the project was successful largely in part to the team consistency and
38、 camaraderie. Over the course of the five-year design and construction period, many of the key team members remained on the project, and multiple team-building events helped members to socially connect away from the day-to-day project stresses. The projects duration was relatively long for several r
39、easons. First, the building was still fully occupied when the project was awarded. In addition, delays in finding tenants to occupy some of the floors contributed to an extended design duration. The projects duration was further extended because the modernization involved many more elements than a t
40、ypical building renovation. The inside was abated and taken back to the outer pre-cast panels, floor slabs, and steel. Then, the building was braced for seismic and blast requirements, the exterior walls were insulated with spray foam, and all of the windows were replaced with high-performing glazin
41、g. All of these time-consuming tasks had to be completed while keeping the building exterior intact because the facility is one of the few 1960s-vintage buildings in the GSAs portfolio and will likely be added to the National Register of Historic Places. Figure 3 below shows the pre- and post-renova
42、tion differences in a typical office. (a) (b) Figure 3 (a) Existing office. (b) Renovated office space CONCLUSION Overall, the office building modernization was a resounding success. Working together, the designers and contactors overcame a variety of challenges to deliver a modernized, energy-effic
43、ient, and inviting office environment to the GSA and its tenants. In addition to using emerging technologies, the design team cleverly applied established techniques in new ways to increase building performance and energy efficiency. In summary, design-build is an effective project delivery method,
44、especially when all team members work together to overcome the inevitable project challenges. ACKNOWLEDGMENTS I would like to thank the entire design-build team, the General Services Administration, and the building tenant agencies for their cooperation, which helped to make the project a success and an overall enjoyable experience.
