Partial-Depth Precast Concrete Deck Panels on Curved Bridges

A critical loading phase on steel I-girder bridges from a stiffness and strength perspective is the placement of the concrete bridge deck. At this stage, the non-composite steel girders resist the entire construction load. Traditionally, intermediate cross-frames or diaphragms are used to provide stability during construction; however alternative forms of bracing are of interest - especially those that increase construction speed and improve economy of the system. While partial-depth precast concrete deck panels (PCP) are often only used as stay-in-place formwork on straight bridges, they have significant in-plane stiffness and strength. With an adequate connection between the PCPs and the top flanges of the steel girders, the PCPs can provide significant contributions to the stability of both straight and curved bridges during construction. This paper documents results of an ongoing research study focused on the development of connection details for PCP bracing applications and the effectiveness of using the PCPs as braces during construction. The experimental portion of this study consists of full-scale laboratory tests on a 72 ft span twin girder system, monitoring the behavior of the system under simulated construction loads for straight and simulated curved girders. Buckling tests were carried out with and without intermediate bracing using a cross frame at midspan. The impact of the addition of the PCPs connected near the ends of the girders were evaluated with the laboratory tests. Additionally, parametric studies with a validated finite element analysis (FEA) of the system will be carried out to evaluate a wider array of systems.

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