Abstract:This paper takes urban elevated steel-concrete composite beams as the research object, the parameters such as sliding effect between deck and steel beam, the number of diaphragm beam, the thickness of deck, the width and span of bridges and the stiffness of main beams are selected, and the influence of various factors on the most unfavorable lateral distribution coefficient under vehicle load of this bridge type is comprehensively analyzed by using the finite element method. The research shows that the interface slip effect of composite beams is within 5% on the most unfavorable lateral distribution coefficient. Under the premise of ensuring the same span, the influence of the number of beams in the composite beam on the most unfavorable lateral distribution coefficient is within 8% and it is even smaller for narrow bridges. The increase in the thickness of the bridge deck will cause the load to be transverse distribution more uniform, and the greater the width-span ratio, the greater the influence of the plate thickness on the most unfavorable lateral distribution coefficient. As the span increases, the most unfavorable lateral distribution coefficient gradually decreases, when the number of main beams is the same, as the width-span ratio increases, the most unfavorable lateral distribution coefficient gradually increases. As the girder height increases, the most unfavorable lateral distribution coefficient gradually increases,but the increase of the t most unfavorable lateral distribution coefficient is within 5%. In the future standardized design, some of the most unfavorable parameters can be used to envelop the remaining parameters, thereby saving design costs and improving design efficiency.