Broadway Bridge tied arches replacement project, AR, USA

Abstract

The new Broadway Bridge over the Arkansas River is located in downtown Little Rock, AR, USA. The Arkansas Department of Transportation replaced the existing historical structure, which was costly to maintain and considered structurally deficient. The new iconic structure consists of two basket-handled 134 m tied-arch bridges, which are designed to accommodate 24 000 vehicles daily, and includes a shared-used path. The US$98 million bridge was completed in 2017. Located along the existing alignment in a downtown metropolitan area, impacts to traffic were a prime concern. The bridge was closed to traffic for 6 months to allow for construction and to float the new arches into place. Throughout design, fracture-critical members were given careful consideration. The tie girder was designed with a bolted connection to prevent a fracture in one plate from propagating throughout the cross-section. It was then analysed as a three-sided section at the extreme event limit state. This internal redundancy minimised the potential risk of a catastrophic structural failure. This paper discusses the design considerations for the fracture-critical members, the construction technique and the expected movement of the main-span tied-arch superstructures.