Six piers constructed as part of a $23-million interchange upgrade in Iowa will have to be modified as a result of a contractor’s measurement error that left them too tall for a planned flyover bridge.

为35/美国州际公路建造的，从22英尺到36英尺的高度从22英尺到36英尺，高度从22英尺到36英尺。明尼苏达州Minnowa Harmony的Ames附近的30号公路交汇处。最近进行的现场调查是为了添加1,690英尺长的连续钢甲板桥，显示了码头与指定高度偏离3英寸的6英寸。爱荷华州运输工程师部。

而该机构和承包商have not publicly identified a reason for the error, IDOT District Engineer Scott Dockstader speculated that anchor sleeves may have become misaligned during concrete pours.

Minnowa Construction did not respond to requests for comment. Local media reported that Minnowa vice president and co-owner Keith Breuning characterized the problem as “a major mistake.”

根据IDOT的说法，承包商已经开始使用较小的碎屑锤击码头上的前30英寸混凝土来保护钢筋钢。水电拆除也将用于加快混凝土拆卸。

接下来，“承包商将确保钢筋符合合同要求，并且现有的混凝土是合理的，” IDOT工程师Jesse Tibodeau说。“然后，他们将安装表格和锚螺栓套管，然后再倒在码头的顶部。”Minnowa将为所有返工付费。IDOT说，第一个码头将在8月初回收。

Construction of the flyover bridge, originally scheduled to take 240 days, has encountered difficulties from the outset. Last summer, improper concrete settlement in the first pier required that structure to be demolished and rebuilt at the contractor’s expense, according to IDOT.

The agency did not estimate how long the current rework will take, though it will likely push the two-year interchange project past the originally scheduled completion date of later this year. Minnowa’s contract with IDOT calls for liquidated damages of $5,500 for each day past the deadline.

该结构的高速公路改进和路堤已经到位。码头修理后，Dockstader说：“这只是设置横梁并倒入天桥桥甲板的问题。”

Built in the mid-1960s, the I-35/U.S. Route 30 interchange currently handles 40,000 vehicles a day, a figure that IDOT projects could nearly double over the next 20 years. It also has highest crash rate of Iowa’s six cloverleaf interchanges, with an IDOT study citing short weaving segments between the loop ramps. The flyover structure is intended to provide a safer transition from northbound I-35 to westbound Route 30.