San Diego State University football fans will celebrate a big day on Sept. 3, 2022, when the SDSU Aztecs take the field for the first time in their new stadium for a game against the Arizona Wildcats.

But for Clark Construction, opening day has represented a daunting milestone as crews have pushed to complete the $310-million project within two years. From the public vantage, the project will bring a new iconic sports facility to the city, but behind the scenes, its success hinged on extensive site preparation, executed concurrently with large-scale demolition and new construction—all under an aggressive schedule.

35,000个座位的Snapdragon体育场设置在160英亩的土地上，以前是高通体育场的地点，高通体育场是圣地亚哥充电器的前家。现有的70,000个座位的体育场位于现场的中心，周围环绕着几乎覆盖其余部分的停车场。

For its redevelopment, SDSU had a bigger vision for what was possible. The new stadium would be set to one side of the site—with limited surface parking—while the opposite side would accommodate a future mixed-use development. The new development, dubbed Mission Valley, is expected to include up to 4,600 residential units, a 400-room hotel and an “innovation district” with 1.6 million sq ft of space to accommodate future research and laboratory tenants.

船员首先建造了体育场最复杂的部分，然后以顺时针旋转进行完整的结构工作。
图片由Aleksey康德拉泰耶夫,克拉克影响ction Group

From a procurement standpoint, SDSU needed to execute each component of the total site redevelopment separately, says Bob Schultz, associate vice president of real estate, planning and development at SDSU. However, both projects had to proceed concurrently.

“They are technically individual projects, but in reality, they are inseparable projects,” he adds.

从一开始就争议的是，原始地点在100年的洪泛区内。舒尔茨说，该大学认识到，在某些地区需要将整个地点提高35英尺，而不是保护新的体育场，还可以使发展对未来的租户更具吸引力。最终，整个站点将需要超过450,000立方英尺的进口填充才能达到所需的高程。

对于克拉克（Clark）赢得了2019年2月建立的合同的该地点的体育场部分，将需要大约150,000立方英尺的填充物。克拉克建筑副总裁阿尔伯特·瓦尔迪维亚（Albert Valdivia）表示，该公司还认识到有必要从物流的角度和业务角度赢得现场开发部分。他说：“一旦我们赢得了体育场项目，我们就希望能够像一项重大工作一样对待它。”“我们知道，如果我们控制整个站点，我们可能会更有效。”

到该开发项目出价时，克拉克及其分包商已经开始了如何以及在圣地亚哥附近找到足够的污垢以满足该项目需求的方面。瓦尔迪维亚说，该团队最终测试了计划清除污垢的近50个项目地点的土壤，确定了35个站点，可以提供足够的时间来满足项目时间表。克拉克（Clark）拥有稳固的采购和定价，能够低于下一个最接近的竞标者的$ 2000万美元。他说：“我们本质上成为了一名泥土经纪人。”“这就是我们赢得工作的方式。”

Adding to the challenge, the site itself also faced geotechnical issues that could present some settlement risks. As a result, crews would need to take the entire site down to 5 ft above the water table, with excavation depths ranging from 10 ft to 35 ft. From there, soils were refilled and recompacted to reduce possible settlement. At any one time, up to 30 scrapers were in use on site. Valdivia says that between the imported fill and the onsite soils that were recompacted, crews moved more than 2 million cu yd of dirt.

With much of earthwork underway in 2020—at the height of pandemic lockdowns—Valdivia says local traffic was light, so the team could keep a steady flow of material into the site. In total, roughly 40,000 truckloads of dirt were transported on site, averaging 115 trucks per day and reaching a daily peak of 400.

To help manage the dirt work, the team used drones in combination with Site Scan software. Drones flew daily, capturing thousands of site photos that were run through the software for analysis. The team overlaid images of existing daily conditions with finished CAD and topographic views, then calculated the amount of fill needed in different areas of the site. From there, data was connected to delivery schedules so the team could track production.

在进口土壤的进口填充和重新分配之间，工作人员移动了超过200万立方英尺的污垢。
图片由Aleksey康德拉泰耶夫,克拉克影响ction Group

Demolition Options

In addition to the massive earthwork required, the team also had to determine how to demolish the existing Qualcomm Stadium. In its master plan, SDSU sited the new stadium adjacent to the existing one with the intent of leaving the stadium in place so the Aztecs could play the 2020 season there while work on the new stadium continued. When COVID hit and athletic schedules were placed in limbo, SDSU decided to move games to another location, where they would be played with no fans in attendance.

随着计划的变化，拆除选项开放了。最初的计划要求进行内爆，这将使体育场更长，使团队能够比传统方法更快地降低它。但是，必须在无法更改的允许日期发生内爆。内爆还冒着触发空气质量罚款的风险，以及清理影响邻近企业的任何灰尘的必要性。另外，内爆将直接发生在新体育场的建设旁边，该体育场在2021年2月的内爆日期将在爆炸式上进行。

克拉克改变了计划from implosion to conventional demolition and saved two months of time.
图片由Aleksey康德拉泰耶夫,克拉克影响ction Group

With more time in the schedule, Clark shifted its plan to conventional demolition, ultimately saving two months and shaving the budget. Valdivia notes that demolition of the above-ground stadium was only one portion of the job; crews also had to remove below-grade foundations, including nearly 1,500 steel H-piles. “Implosion would have gotten us down halfway, then it would have just been a pile of rubble,” he says. “[By using conventional demolition] we had it pretty much leveled in March, and we still couldn’t get all the foundations out until September. Implosion wouldn’t have helped because we still had to address below grade.”

With site soils properly compacted, crews put in foundations for the new stadium. With no underground spaces in the stadium, which was designed by Gensler, one side of the stadium sits on traditional footings and an elevated slab while the other uses slab on grade.

For the structure, a combination of cast-in-place concrete, precast concrete and steel was used. “We had to hustle with the concrete to get ready for steel,” Valdivia says. “Then, the steel had to get up quickly to get the rest of the concrete up. So there wasn’t a clean handoff. That was a challenge versus just having more of an all-steel or all-concrete structure.”

When completed, the Gensler design will deliver a stadium that emphasizes open air spaces.
照片由Gensler提供

Crews started by first building the more complex portion of the stadium, which featured premium seating spaces. From there, they worked in a clockwise rotation to complete construction. Although the stadium is being delivered at a capacity of 35,000 spectators, it is designed to be expanded as needed, potentially accommodating up to 40,000 additional seats. As such, soils around the stadium were improved to accommodate future structural needs.

When completed, the Gensler design will deliver a stadium that emphasizes open air spaces. “We took inspiration from around San Diego, where people go on the weekends,” says Steve Chung, design director at Gensler Sports. “We drew inspiration from the beach communities and the craft food and beverage experience that is uniquely San Diego.”

在大多数体育场中，在传统上是较便宜的座位，Gensler设计的开放式甲板可以引用圣地亚哥的码头。码头将为500人提供站立室，可随时可以使用酒吧和特许空间。

“Those piers will be an iconic aspect of the stadium,” Shultz says. “It’s part of the vibe of coastal San Diego.”