Steel-UHPC lightweight composite bridge girders for long-span bridges

The text in this paper is for visual purpose only. No rights can be taken from this. Practice has shown that there are some drawbacks with two types of widely-used bridge girders: orthotropic steel girders and steel-concrete composite girders. The orthotropic steel decks (OSDs) are prone to premature fatigue cracks while concrete slabs in the steel-concrete composite girders usually develop cracks at the negative moment zones. To overcome these drawbacks and to develop efficient and durable bridge girders for long-span bridges, this paper proposes three types of steel-UHPC lightweight composite bridge girders (Figure 1), where UHPC denotes ultra-high performance concrete. The first two types of composite girders consist of either a conventional OSD or a simplified OSD and a thin UHPC layer while the third type consists of a steel beam and a UHPC waffle deck. The steel-UHPC composite girders are free from premature deteriorations such as fatigue cracking in the OSDs and damages in the asphalt overlays. Meanwhile, with light self-weight, these composite girders can eliminate the cracking in the negative moment regions. These advantages all make them a competitive solution for long-span bridges. Figure 1 Schematic of three types of composite girders. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig169_1.tif"/> This paper presents the excellent performance of the novel composite girders by illustrating theoretical and experimental studies performed. The studies reveal that the composite girders can meet the design requirements under both static and fatigue loads.