EFFECTIVE SLAB WIDTH OF SIMPLE-SPAN STEEL I-BEAM COMPOSITE BRIDGES AT ULTIMATE LOAD

The purpose of this study is to evaluate the effective width of simply supported composite bridges at ultimate load. An analytical method was developed by which the elastic and elasto-plastic deformations of such a system can be predicted. The resulting equations were solved by a computer program. Using the computer program, many typical two-lane composite bridges were analyzed. The effective widths at ultimate load were then determined and were found not to equal the effective widths at the elastic condition. The effective widths at ultimate load can be represented by the following: (1) Interior girders 2be/b = 0.617 b/L + 0.702; 2be greater than bridge width/no. of girders. (2) Edge girders 2be/b = -1.98 b/L divided by 0.873; be less than bridge width/no. of girders. /FHWA/