Historically, building roads across the Mountain State has proven an arduous task. So when the West Virginia Parkways Authority undertook an ambitious 30-year deck replacement program on the West Virginia Turnpike, it looked for alternative methods to ease the pain. WVPA plans to use accelerated bridge construction (ABC) to replace decks on nearly all of the 116 bridges along the 88-mile turnpike that have been identified for replacement. Using ABC, concrete panel decks are prefabricated off site and then installed within a highly compressed schedule, saving months of onsite construction time when compared with conventional methods.

WVPA维护主管吉姆•梅多斯说the authority needed to find a way to replace its bridges without causing significant delays for its toll-paying patrons. The team estimated that using conventional bridge deck replacement construction on each bridge could take between six and eight months, causing significant disruptions.

他说：“我们意识到[甲板替换计划]沿着这条路驶入这条路时，我们将面临关闭。”“我们必须找到一种更好的方法。”

The plan to use accelerated bridge construction was recommended by HNTB, which serves as general engineering consultant for WVPA. HNTB estimates that by using precast panels with ABC construction methods, construction time could be limited to between seven and 12 days. Given the short timeframe, construction teams could also schedule construction to avoid peak summer traffic by working after Labor Day and before Memorial Day. Construction could also be sequenced to eliminate shutdowns, allowing one lane of traffic to continue to flow through active construction zones.

That level of convenience comes at a cost. On the first three bridges completed under the program, construction costs ranged from 15% to 20% higher than estimates for conventional methods. But Meadows says that keeping its toll-paying customers happy is worth those extra construction dollars.

“If we have conventional construction going on for months, [a customer] could decide that instead of driving the turnpike, I’ll go another route because I don’t want to pay a toll and sit in traffic,” Meadows says. “Conventional replacement would push construction into the summer, when going down to one lane could mean a 10-mile backup. That’s unacceptable.”

还必须避免完整的关闭，因为穿越西弗吉尼亚州山区曲折的当地道路的绕道可能会增加驾驶者的开车时间。Meadows指出，通过减少现场施工时间，也可以减轻与主动建筑区域有关的安全问题。

从计划到施工完成

虽然现场建设仅限于在two weeks using ABC, each project can take up to two years to plan, design, bid and construct. Randy Epperly, group director for engineering and vice president at HNTB, says the firm created design standards specific to the program to help create consistency across each project. In keeping with methods used by HNTB on other ABC programs around the country, the project uses prefabricated cast-in-place concrete decks. HNTB designed the panel layouts to maximize repetition in panel dimensions and other specifications when possible. The decks are designed to connect to each other using rapid set concrete closure pours. Shear pockets with stud clusters and grout are used to connect panels to steel girders. Each panel is also cast to include corresponding parapet walls.

WVPA uses a lot of brine in the winter months to pretreat its roads, so it specified applying an asphalt overlay to decks after installation to help reduce exposing the concrete to salt.

Given the need for consistency and quality in panels, WVPA requires all panels to be prefabricated off site. “We felt that in a casting yard there are better controls of materials, construction methods and safety,” Epperly says.

Some panels used on projects so far have been fabricated in facilities that are more than five hours away from jobsites, so Epperly says the panels had to be designed to be easily transported to the site.

Although the bridges follow common design standards, Epperly says the team spends at least six months in design on each bridge. Contractors also need more than six months to prefabricate the panels off site for each project, he adds.

First Use of ABC in W. Virginia

加速的桥梁建设仍然是一种新兴方法，尤其是在甲板替换计划启动之前在西弗吉尼亚州没有使用。尽管它是新的，但Epperly表示，这些项目的设计方式使任何合格的承包商都新利18备用网址可以考虑使用该方法。他说，最大的挑战是完全了解施工顺序的需求。随着时间表从几个月到几天的压缩，任务将在一个小时内分解，有时会有半小时。

Work on each side of the four-lane highway is sequenced so that one lane of traffic always remains open while decks on the neighboring lane are replaced.

该项目的目标是交付速度，WVPA将大部分风险置于其承包商身上。无论恶劣天气或其他因素如何，都必须满足施工时间表。如果未达到交货日期，承包商将面临经济罚款。

为了避免传统的信息请求并加快在施工过程中发现的任何现场问题的解决，WVPA始终将专业工程师分配在施工现场。梅多说：“我们的工程师每分钟都在工人的身边。”“如果这是一个工程电话，他们就可以自由地当场打电话。”

With its first bridge completed in May 2016, Epperly says the team learned some lessons. It rained during most of the bridge’s construction, making it difficult to add a specified waterproofing membrane. Epperly says the contractor “force dried” the deck to stay on schedule, but that wasn’t sufficient and it resulted in some failures. WVPA will now consider allowing schedule delays during the waterproofing portion of each project on a case-by-case basis. At the suggestion of a contractor, WVPA also changed its specification to call for spray-on waterproofing, which Epperly says is easier to maintain.

HNTB还使用第一个桥梁上的甲板面板之间的沥青塞接头代替标准装甲接头进行了测试。Epperly表示，该团队希望沥青塞的设计能够通过将水从面板之间的关节中排除来减少维护需求。但是，他说这并没有比装甲接头更高效，因此WVPA改变了标准。

Half the Onsite Personnel Required

劳动力需求在使用ABC方法时提供了另一个重要的差异。Brayman Construction重型民事部门副总裁蒂姆·泰勒（Tim Taylor）表示，与类似的常规甲板替换项目相比，该公司将在9月建造的两座桥梁建设期间拥有50％的人员现场人员。泰勒说，在施工劳动力短缺的时候，提出了重大挑战。

布雷曼（Brayman）正在建造两个桥梁（相距约一英里），同时它正在附近的另一个道路项目。泰勒（Taylor）表示，该公司竞标这项工作的主要原因是因为它知道它可以从其他道路项目中吸收资源来帮助支持WVPA桥梁。该面板还将由一家独立但有关联公司的Brayman Precast进行预制。

Taylor says that the company has done other ABC projects outside of West Virginia, but that it does so on a select basis in part because of the labor demands. “From a corporate perspective, we’re happy to see the use of accelerated bridge construction, but we wouldn’t want to see the industry go 100% in that direction,” he says. “On select projects where we have workforce in the area, we will absolutely bid. But if every job went like that, we wouldn’t have the workforce to handle it. It’s not possible.”

Epperly表示，WVPA正在考虑将未来的项目做出考虑。新利18备用网址他说，在有意义的地方，WVPA将捆绑项目以吸引更多的竞标者。新利18备用网址

在确定将放出哪些桥梁以及梅多斯说WVPA考虑多个因素的何时，而年龄和维护历史是主要驱动因素。大路上的桥梁的平均年龄为35年，最古老的桥建于1977年，是1996年最新的桥梁。在该计划之前，没有更换这些桥梁的甲板。Meadows领导正在进行的桥梁检查和维护计划，该计划跟踪每座桥的桥梁条件和维护成本。新利18备用官网登录他说：“我们知道哪种桥梁花费了我们最大的损失，所以那是我们首先瞄准的桥梁。”“这使我们能够搬到其他桥梁，在那里我们进行更多的预防性维护。”

Meadows notes that some of the more complex bridges are likely to be let later in the program. That could include several in remote locations with significant changes in elevation on site and other factors that could make prestaging equipment and materials very difficult.

Epperly says the team is also evaluating if only steel structure bridges—which make up the vast majority of its inventory—will be candidates for ABC deck replacements. Some bridges with concrete beams might be considered for the ABC program if the team can assure that the structure won’t be compromised during demolition of existing decks. The parkway also has a few truss bridges, which Epperly says are unlikely to be part of the program. “We don’t see how you could stage the equipment to make that work,” he says.

WVPA is paying for the program entirely with toll revenue. Under the current plan, WVPA has budgeted roughly $15 million annually for the next few years, gradually escalating to more than $30 million annually by 2030. At that rate, Meadows expects the program to average three or four replacements per year. He also notes that, while its bridge decks do need to be replaced, none of them are critically deficient. “We can take advantage of the market,” he says. “If the prices are coming in high, we can pull back [the program] a little bit. If the market is good, we can be more aggressive.”

无论何时解释桥梁工作以及最终使用ABC方法有多少，Meadows说WVPA已经看到了好处。他说：“即使我们在该计划下只完成了80％的重新订阅，但对于我们的顾客来说，这仍然很方便。”“我们会为他们节省很多悲伤。”