A Pilot Study of Factors Affecting Live-Load Distribution in Prestressed Concrete Beam-Slab Bridges

摘要

This report describes a very brief pilot study of the structural behavior of prestressed concrete beam-slab bridges, particularly live-load distribution, as affected by (1) curb-parapet sections, (2) intra-span diaphragms, and (3) continuity over the supports in multi-span structures. For simple span bridges, it was found that consideration of the longitudinal strength and stiffness of the curb-parapet sections yields higher values of the live-load distribution factors for exterior beams and lower values for interior beams, when compared with distribution factors based on analyses which ignore the effects of the curb-parapet sections. The effect of intra-span diaphragms is to more evenly distribute the live load to the individual longitudinal beams. A diaphragm at midspan was found to be more effective than other combinations considered. For multi-span bridges constructed with longitudinal continuity over the supports, the live-load distribution was found to be similar to the distribution in simple span bridges of shorter span.