Buffeted by hurricanes, northwest Florida’s largest-ever infrastructure effort is finally seeing the light at the end of the storm. The three-mile-long bridge across Pensacola Bay is expected to reopen to traffic this spring after an ongoing replacement effort abruptly became an emergency repair job as well.
On Sept. 15, 2020, with Hurricane Sally’s approach to the Gulf Coast bringing gusts in excess of 39 mph, the Florida Dept. of Transportation (FDOT) took the routine precaution of closing the bridge across Pensacola Bay to traffic. Nobody knew that it would be at least six months before the crossing would reopen.
萨利（Sally）轨道上的最后一刻向东转移，将风暴的眼睛带到了桥梁30英里以内及其部分完整的平行结构，由美国东南部Skanska建造。在暴风雨期间的某个时候，风向的波浪从停泊处释放了27艘建筑驳船，将它们散落到搅动的海湾中。数量未知的船只在多个位置撞到了现有的桥梁，完全切断了一些跨度，并在其他地方留下了深刻的污垢。
It would be several days before inspections revealed the full extent of damage. FDOT’s drone surveys and other preliminary images left little doubt that a challenging restoration effort lay ahead. FDOT and contractor representatives did not make themselves available for interviews, but the agency has shared many aspects of how the recovery and repair effort has unfolded via press releases, video updates and its public information website.
Landmark Crossing
这座损坏的桥梁于2019年开业，是FDOT耗资4,30万美元计划的一部分，该项目替换了彭萨科拉市中心和墨西哥湾郊区的一座现已退役的1960年代桥梁，并用双三车道结构。该项目还包括彭萨科拉市中心的新交汇处以及对海湾微风往往返道路的改进，旨在扩大通勤交通的能力，该通勤交通每天达到55,000辆汽车，并升级了一条关键的飓风撤离路线。
The design-build project began in 2016 with Skanska, lead designer WSP and Eisman & Russo Inc. Each 65-ft-high steel-reinforced precast bridge sports a 375-ft-long, 83-ft-high steel-plate arch supporting a 10-ft-wide multiuse path. Prior to Sally, the parallel bridge was on track for completion in late 2021.
但是，在莎莉之后，这是一个很大程度上平稳的建筑过程，呈不确定性。当风暴离开该地区时，FDOT和团队动员了检查员评估两座桥梁的状况，而八支潜水队评估了水下基础和潜在的碎屑损坏。
At the outset of the inspections, Eisman & Russo senior project manager Glenn Peterson said in an FDOT-produced video that while the surviving bridge spans appeared in good shape, the team had to carefully scrutinize the structural load carrying capacity of individual components.
“The beams are the easiest to see, and they were really badly affected in several areas,” Peterson said. “When we can see the load-carrying steel member has been damaged, we have to consider how badly it’s damaged. When we see it’s exceeded a certain point where it can’t be repaired, we have to replace it.”
Damage assessments revealed that 70 155-ft-long beams required replacement, along with 14 of the 250,000-lb trophy pieces and eight 150-ft by 59-ft spans. Another 14 spans required partial replacement, while 12 spans of the multiuse path had to be rebuilt.
Despite criticism of its pre-hurricane preparations, Skanska continued to serve as lead contractor. FDOT set a goal of having the bridge fully repaired and open to traffic by March. Skanska augmented its resources with two more contractors and four salvage companies.
According to a Skanska statement, the repair workforce grew to nearly 400 craft and staff workers handling demolition and reconstruction, salvage and pile operations and concrete fabrication. Equipment resources were bolstered as well, including the addition of five barge-mounted cranes to replace equipment damaged or lost during Hurricane Sally.
平行桥的其他现有桥梁施工资产同样将使维修工作受益。在附近的Bayou Chico建立的一个预制院，加强了奖杯和横梁的制造，并在坦帕（Tampa）单独的预制设施提供了额外的桩。
Before repair work could get underway, contractors had to conduct an extensive waterborne demolition effort to remove damaged sections as well as subsurface concrete and steel debris. There was also the matter of removing four wayward barges lodged beneath the structure without causing additional structural issues. Contractors applied a variety of methods to remove damaged components as quickly and safely as possible. According to FDOT’s website, one method involved the use of a specialty barge equipped with self-propelled mobile transports (SMPTs) positioned beneath a damaged span.
After crews saw-cut the span lengthwise over the centerline of the piers, the SPMTs lifted and moved each section to the other side of the barge for transfer to a second barge. The sections were then transported to shoreside areas for demolition and unloading. Larger pieces of debris were delivered to an artificial reef site.
The bustle of activity was interrupted in late October as Hurricane Zeta made its way toward the Louisiana Coast. With barges and equipment relocated and moored in secure locations away from the bridge to ride out the storm, Zeta passed without causing further damage, allowing repair work to quickly resume, albeit with damage assessments still in progress.
Eisman＆Russo计划总监Brett Pielstick在FDOT制作的视频中报道说，某些不安全的领域直到11月中旬才清除进行重建。Pielstick说：“到处都有潜水船来帮助我们完成评估，因此我们确切地知道我们必须做的范围。”FDOT尚未说过维修工作是否影响了该项目的活动水平或完成时间表。
By December, pile-driving for new spans was underway in earnest. According to FDOT, the process was synchronized with removal of damaged trophy pieces and waterline footings, followed by saw-cutting the four-pile clusters at the mudline. A 20,000-lb diesel-powered hammer drove new piles in clusters of six to avoid conflict with remnants of the old piles, followed by installation of a new footing and trophy piece.
December also brought another unwanted sense of déjà vu, with FDOT reporting that a Skanska-owned barge had broken loose and become stuck against private docks near the bridge. Along with reviewing its mooring practices, the company launched an investigation with state and local authorities to determine if the line connecting the barge to the sea floor had been severed intentionally. Results of the investigation have not been made public.
专注于Finishing
The project team achieved another repair milestone in mid-January, with FDOT announcing the start of concrete pours for the first new bridge deck. The agency also reported that casting of all new piles and beams was complete, with installation projected to be complete by the end of February. According to FDOT’s remaining schedule, beam erection, deck pours and nonstructural repairs on the bridge are scheduled to be completed in March. The final steps to reopening—barrier wall, striping and electrical work—are due to be completed by month’s end.
Though it seems likely that FDOT will complete restoration work on time, many questions remain about the incident itself, including responsibility for a final cost that has yet to be determined. From the outset, FDOT has publicly asserted that “once the situation is fully assessed, and damages are fully understood, appropriate parties will be held responsible for the repairs.” For its part, Skanska has said little beyond initial public statements that it had done all it could to secure its construction barges prior to the change in Sally’s storm track.
一份公司声明说：“整个彭萨科拉社区的强度，方向和持续时间的突然转变是前所未有的，并且完全出乎意料。”“不幸的是，在风暴的突然强化与最终登陆之间的短暂时期内尝试拆除驳船和其他设备既安全也不可行。”
Whatever public plaudits Skanska may receive from its contribution to restore the bridge will likely be overshadowed by the dozens of lawsuits from local businesses and property owners claiming economic losses as a result of the bridge closure. The company is awaiting a federal court to rule on its assertion that maritime law applies to the incident, thereby limiting liability to each barge’s approximate value, which range in legal filings from $125,000 to $550,000.
For now, the project team is focused on fulfilling a commitment Peterson expressed at the outset—having the Pensacola Bay Bridge restored with the full design life of 75 years, “so we have the full service and not a diminished service level.”
