Research on Anti-Cracking Design Method of Steel-Concrete Composite Beams in Negative Moment Zone

Steel-concrete composite girder bridges have been widely used in practical engineering because they can make full use of the two materials and have unique advantages. However, the negative bending moment produced by the fulcrum of steel-concrete composite continuous beam bridge is very easy to cause cracking of concrete deck. At present, the common design method is to pre-stress the concrete deck at the fulcrum by dropping the beam, so as to prevent the cracking of concrete deck. Based on ABAQUS finite element software, this paper establishes the full bridge model of the real bridge project and simulates the falling beam construction. The results show that the simulation method can better simulate the drop beam condition of steel-concrete composite beam, and the drop beam condition can effectively prevent the cracking of concrete bridge deck at the fulcrum; with the increase of the drop beam height, the pre-compressive stress of concrete bridge deck at the fulcrum shows a significant increase trend; through analysis, the drop beam height of 50cm is determined for this practical project, which provides a rationality for similar projects.