Finite strip evaluation of effective flange width of bridge girders

Concrete and steel–concrete composite beam-slab type and box-girder bridges are analyzed using the finite strip method, a variation of the powerful finite element method. The results obtained are used to determine the effective width of the compressive flange of the bridge girders. A study of a wide range of bridge models resulted in an empirical relationship that is in good agreement with the design criteria set down in the composite road bridge design code of the Federal Republic of Germany.The empirical relationship presented in this paper is intended to supplant the effective width specifications in current American and Canadian design codes, which in general lead to conservative designs.