49ers Use 'Integrated Bridging Design-Build' To Speed Stadium Construction
For five uneasy years, the team responsible for building the San Francisco 49ers' $1-billion new home had hung together through three work hiatuses, a recession and a regrouping caused by a site relocation 45 miles to the south—from San Francisco's Candlestick Point to Silicon Valley's Santa Clara. Then, early last fall, things changed. Suddenly, the snail's pace became a race.
Based on an early opportunity to secure financing, the 49ers and the Santa Clara Stadium Authority, which will own the New Santa Clara Stadium, decided to accelerate the opening by one year. They are pulling all the stops to finish in time for the 2014 season of the National Football League. "It was like drag racers warming up their tires with short bursts forward at the starting line before the race begins," says Jon D. Magnusson, president and CEO of project structural engineer Magnusson Klemencic Associates (MKA), Seattle. "Then, all of a sudden, it was go, go, go."
Plans by the Los Angeles office of HNTB Architecture call for a nearly 1.9-million-sq-ft facility with 68,500 permanents seats, including 165 suites, and the ability to expand to 75,000 for the NFL Super Bowl. For construction, the stadium authority named the 49ers' Stadium Development Co. (StadCo), Santa Clara, as its agent. StadCo will lease the facility under a long-term agreement. Major financing is from a group of banks led by Goldman Sachs.
The project has at least two claims to fame. The 49ers team is the first sports franchise—and perhaps the first owner or developer—to use a hybrid, collaborative project delivery model—from day one—that combines the best features of several delivery systems, including integrated project delivery.
Dispute Avoidance
"We landed on this delivery system in 2005 after looking at prior stadium projects with cost overruns and disputes between the owner, the architect and the contractor," says Larry MacNeil, the 49ers' executive vice president for development. "We are trying to eliminate potential disputes and limit the owner's ultimate risk," he adds.
The second distinction is that the steel structure—designed to resist seismic loads through a braced frame—is the first NFL stadium to use buckling-restrained braces (BRBs). The 529 BRBs, which resist lateral loads, have structural and architectural benefits, in terms of earthquake resistance and design flexibility, over conventional braced frames or shear-wall structures (see sidebar, p. 36). "This is the most extensive use of BRBs on any sports facility, to my knowledge," says Wayne Searle, CEO of SME Steel, West Jordan, Utah, which is the lead firm for the job's steel contractor, the SME/Herschfeld Joint Venture.
The delivery model, which Magnusson dubbed integrated bridging design-build (IBDB), is an enhancement of bridging design-build. A big difference is that the bridging architect and, in this case, the structural engineer that first work for the owner/developer become designers-of-record in the design-build phase.
"For this project, in a seismic zone, the need for continuity of the structural engineer from start to finish is paramount," says Jeffrey R. Appelbaum, managing director of Project Management Consultants, Cleveland. PMC crafted the delivery model for the 49ers based on earlier bridging design-build models developed for other sports venues.
To allay concerns about compromised architecture during the design-build phase, the 49ers have "contract limits with HNTB that say it will not produce any design in phase two that would be inconsistent with phase-one design," says Appelbaum.
The "integrated" in IBDB means the presumptive design-build contractor is brought in at the project's onset to help with estimates and constructibility under a preconstruction services contract. The owner has the option to hire a different design-build contractor if it is not satisfied with the proposed guaranteed maximum price (GMP) or for any reason. Major subcontractors are also brought in early to assist with design.
The 49ers hired the local Turner/Devcon, Joint Venture (TDJV) for preconstruction services one month before it hired HNTB. But the Santa Clara-based 49ers and Devcon Construction Co., Milpitas, Calif., go way back. The 49ers first engaged Devcon, which is well established in the Santa Clara area, for preconstruction services in mid-1997, when San Francisco passed ballot measures for the stadium and a mall project at Candlestick Point, the 49ers current home. That effort went dormant in 1998. Devcon continued to assist the 49ers with estimates and other services.
The project almost came alive in 2001, but no team was selected. Then, in 2006, the 49ers issued two requests for proposals—one for the architect and one for preconstruction services. That RFP had Devcon listed as a partner, says Jonathan Harvey, TDJV's co-director and a Devcon vice president. In March 2006, the San Francisco office of Turner Construction Co. was selected as the national contractor with sports construction experience. The site switch and modest redesign happened in 2008.
StadCo retained the joint venture as the design-build contractor earlier this year after a GMP had been established. TDJV's $854-million design-build contract is actually with the stadium authority. HNTB and MKA were transferred to TDJV in June.
High Gear
The job went into high gear over Labor Day weekend in 2011, when the 49ers' MacNeil gathered his team to consider whether an early completion was doable. Within a few days, the members of the building team, who had been working together on and off for five years, decided they could get the job done, but it would mean pulling out all the stops. To regroup, the team, among other tactics, phased and streamlined the design schedule, "stacking it" over construction. "We shortened design by seven months and went out to bid seven months earlier," says Harvey.
Speeding things up was not easy, adds David J. Masel, TDJV's general superintendent and the acknowledged mastermind of the "rush" strategy. "We had to take into account all contingencies. We didn't have the design or drawings, so we plugged into historical data onto scopes of work," says Masel.
Buy-in from all of the design and construction teammates—from individuals, not just the firms—was essential for the accelerated plan to work, says Jack W. Hill, StadCo's project executive. Hill, an owner's representative based in Dallas, joined the team over that Labor Day weekend.
IBDB allowed the team to quickly devise a phased permitting plan and site utilization and staging plans. The full-team cooperation allowed HNTB to get commitments from MKA on a phased delivery of documents for structural packages and on a greater overlap of design and construction than is typical, says Hill.
"There are probably not too many projects with as much camaraderie and connectivity," says Joseph J. Diesko, HNTB's vice president-director of sport architecture. "A lot of owners believe adversarial relationships produce better results," he adds. "That is not the case here. This has been a great process."
In the accelerated scheme, structural steel was on the critical path. TDJV first asked MKA what could be done to get the basic steel design in a huge hurry—by early last November. "Then, we worked with our estimators to make sure the right allowances were in the estimates," says Robert L. Rayborn, TDJV's co-director and a Turner construction executive.
As a result, in the middle of design development, MKA moved into construction documents. "We had to consider the structure set and let MKA go, or we would not be able to coordinate the mill orders," says Diesko. HNTB "froze" the structure, as if it were an existing building, much earlier than is typical, adds Lanson Nichols, HNTB's vice president.
The strategy worked. "We got our first design development package to buy structural steel and vertical transportation in November 2011," says Harvey.
After design development, the new schedule eliminated a two-month "pencils down" period for the design team so the joint venture could create the GMP. It is also slicing two months off the original 28-month construction schedule.
TDJV's contract calls for substantial completion in August 2014. That cuts out a typical three-month buffer between substantial completion and the first game.
About a year ago, the team had a meeting with the city to develop a multiple drawing-package review strategy for phased permitting of the steel structure, the foundations and the concrete. To expedite the steel permit, MKA proposed combining a peer review of the structure, which the 49ers wanted, with plan checking. For this, the city agreed to deputize structural reviewer John A. Martin Associates (JAMA), Los Angeles, as part of the building department.
"We also did a courtesy review," says Sheila Lee, building official for the Santa Clara Planning & Inspection Dept. "This is a very challenging project for my department because of the size and tight time line. We don't compromise anything."
MKA split the structure into eight plan-check packages, submitting them in stages from Nov. 4 to Feb. 17. While JAMA reviewed one package, MKA continued to engineer others. This strategy saved a minimum of two months over a more traditional two-step foundation-and-superstructure review process, says Brian A. Dickson, an MKA principal.
To speed work, TDJV's Masel split the building into four quadrants and constructed them concurrently instead of using more traditional, "racetrack" oval sequencing. Crews used four drill rigs for the auger cast piles, for example. Workers are erecting steel with four crawler cranes, one for each quadrant.
TDJV is using building information modeling for interference checking. To date, there are 402 requests for information, instead of three or four times that amount, thanks to IBDB with BIM, says Harvey.
BIM also was used to locate and build the deep utilities below the slab on grade so they could be built ahead of piles instead of after them. Crews worked 24-hour shifts from May 1 to May 15. That move cut the time in half for the deep utilities work, says Harvey.
Out of Sequence
TDJV had field-level electrical rooms, made of cementitious masonry units, built out of sequence. That move allowed the electrical switch gear, transformers and panels to arrive early so the electricians can streamline the electrical rough-in and distribution. These rooms would fall under normal field-level CMU and drywall construction, after fireproofing, and potentially cause delays in construction, says Harvey.
Crews have been installing sleeves, block-outs and inserts in the metal decks on swing shifts. The same is true for slab-on-metal-deck pours. This tactic allows for continuous steel erection during the day.
On June 1, more than one month after construction started, HNTB and MKA were officially assigned to TDJV. Because of the acceleration, WSP Flack + Kurtz, the bridging mechanical-electrical-plumbing engineer, did not get transferred to the design-build team. To expedite the work, the team made a decision to bring in a design-build mechanical contractor.
Work started on April 23 and is speeding along. Steel erection began on July 30 and is 77% complete. Topping out is expected in December. On Sept. 4, tower cranes started lifting in escalators. "To see escalators actually set at this stage is phenomenal," says HNTB's Diesko.
On Oct. 26, crews installed the first piece of structural precast concrete for the seating treads and risers. The project is on course for substantial completion one month ahead of even the accelerated schedule, says Harvey.
The IBDB and acceleration strategies have worked out so far, says the 49ers' MacNeil. "We are pleased with the design-build team," he adds. But with only 22% of the project complete, the race is far from over. "We haven't deployed the parachute yet," says MKA's Magnusson.
