Analysis on Traffic Load Effect of Simply Supported Beam Bridge Based on WIM Data

The actual load distribution of different types of vehicles is analyzed based on the traffic load data of a month recorded by a WIM system installed in Zhongjiawan overpass located in Shaoxing section of National Highway No. 104. The maximum bending moment of the mid-span and the maximum shear force of fulcrum of simply supported beam under each passing vehicle load recorded by the WIM system are calculated according to the principle of influence line loading. The internal force distributions of 12 kinds of simply supported beam bridge,whose spans are from 6 m to 50 m,under actual traffic load are analysed,and these values are compared with the effect values of the traffic loads in current bridge design specification. The results show that for the actual traffic load in this road section,the smaller the span of the simply supported beam bridge,the larger the vehicle number of actual traffic load effect value beyond the effect value in current specification.