在3月29日的一周中，机组人员将三个巨大的预制混凝土盒推入了佛罗里达州布里瓦德县的一条活跃的高速公路下方，这是40亿美元的Brightline高速铁路计划的一部分，该计划将延伸到Orlando。迈阿密和西棕榈滩。
box-jac官员认为这是第一次king method, first used in the U.S. on the Long Island Rail Road Extension (ENR 9/2-9/19 p. 18), has been used under live highway traffic.
该系统的私人运营商Brightline的执行副总裁Michael Cegelis表示，花岗岩建筑将铁路隧道作为其5.5亿美元，35.5英里部分的一部分。承包商在招标过程中提出了该方法作为替代技术概念。他说：“否则最多需要一年”才能使用常规方法建造隧道。
Granite Project工程师C.J. Kaufman说，在2018年赢得了竞标后，该团队与意大利公司Petrucco会面。他补充说，该团队使用该系统在去年秋天短短9天内完成了地下通道，并“使用那里学到的经验教训来调整我们的设计。”
机组人员为高速公路安装了临时支撑，然后在可可528号州际公路以南建造了三个箱子段。“然后，我们开始将盒子推入SR 528的位置。总千斤顶长度为332英尺。…总重量是2400万磅。”考夫曼说。
It wasn’t possible to shut down 528 except for limited nighttime closures, so the team relocated eastbound traffic onto the westbound lanes. “We had the whole eastbound road to excavate. We pushed the underpass under it and excavated in front of it,” says Kaufman. “Then we got to a point where, to advance the underpass under the westbound road, we had to relocate at least one of those lanes to the former eastbound location.”
The concrete segment tops were lubricated so that a steel-plate system on the underbelly of the highway wouldn’t move along with the box slide, says Cegelis. “There is a truss system placed in front of the plates that resists as the box jack moves forward, so the steel plate system remains stationary with the roadway on top of it,” he adds.
The three precast concrete boxes weigh between 3,300 and 4,600 tons. The push was intended to progress at approximately 3 ft per hour, with up to 50 workers working 12 hours. “At the end of the day, overall progress was about 1.15 feet per hour,” says Richard Brown, Granite project director. Compared to the bridge placed last fall, “there was a lot more sand here. There were more clays.”
The unexpected conditions extended the two-week operation by about three days. The completed underpass is 31 ft high by 43 ft wide and will accommodate two trains side by side while eliminating the need for an at-grade crossing.
总体奥兰多铁路扩展项目覆盖了从西棕榈滩到奥兰多国际机场的170英里，分为四个区域。其他主要承包商包括Middlesex，Wharton Smith和Herzog，Stacy Witbeck和Railworks的合资企业。
The new alignment follows SR 528 on the south side from Cocoa to the airport. Cegelis notes that other innovative solutions on Granite’s job include a shoofly—a temporary bypass—used in order to build an underpass beneath I-95 without road closures and a 150-ft-long conveyer system carrying material over 528 that saved 27 miles of truck trips. Construction of the $2.7-billion phase is expected to be completed in late 2022.
