Development of design criteria for continuous composite I-beam bridges with skew and right alignments.

摘要

Influence of different variable on the structural performance of two lane, two span, continuous composite I-beam bridges were investigated. A linear, elastic, finite element analysis of 288 bridges was done for both positive and negative moments. All these structures had a regular geometry, with a uniform concrete deck resting on five identical prismatic and equally spaced steel built-up plate girders. Spans ranged from 44 to 124 feet, girder spacing 6 to 10 feet, skew angle varied from 0 to 63 degree, and, thickness of slab was between 6 to 12 inch. Similarly, AASHTO 89 and 94 loading provisions were incorporated in producing maximum positive and negative bending moments in the girders. A computationally efficient mesh for the finite element model was finalized after conducting a detailed convergence study on different simply supported and continuous bridges.;A wide ranging parametric study was carried out to critically evaluate the behaviour and response of skew and right I-beam bridges. All these geometric, structural, and loading parameters were varied one at a time, and, their influence on the bridge performance were noted. Based on the results of the parametric study, simplified expressions for the design of interior and exterior girder were developed. These design equations take into account girder spacing, bridge span, skew angle, and relative stiffness of steel girder and concrete deck. Format of the simplified design procedure was same to which a common bridge engineer is most familiar with. Subsequent comparison between the results of the proposed simplified design procedure with approximate design methods of 89 and 94 AASHTO codes was done.