This manuscript presents simple relationships for calculating the live load distribution factor for glued-laminated- simple spans deck-on-girder timber bridges. Analytical models for four in-service timber bridges that were previously tested by others and several typical glued-laminated bridges were developed for the ANSYS finite element program. These models accounted for the orthotropic behavior of the timber, the connectivity between the deck panels and the as built bridge support conditions. In addition, the effects of the bridge span length, the spacing between the bridge girders, and the bridge width on the distribution of the live load among the bridge girders were investigated. The bridge models were subjected to one or multiple lane loads. These loads were positioned at different longitudinal and transverse locations on the bridge deck to induce the maximum moment and shear forces in the exterior and interior girders of a bridge. Thelive load distribution factors that were obtained from the analytical models were compared to those obtained using the AASHTO-LRFD live load distribution relations. The comparison showed that the live load distribution factor obtained using the AASHTO-LRFD were conservative when compared to those obtained using analytical models. For this reason, statistical methods were utilized to develop simple and accurate relationships that can utilized in calculating the live load distribution factors for the design of glued-laminated bridge girders. The results of the developed relations were compared to similar results that were obtained from the test of the in service bridges.
Samenvatting