Effect Factors Analysis To Tensile Crack Width Of Double Composite Beam

There was one German scholar put forward a new kind of beam which named double Steel-concrete composite beam. Why its property could be made good use is because of its bottom concrete shutter which help steel beam to suffer the load together. In a way, due to the lower concrete plate, increased the stiffness and load capacity of double composite beam, so that every parts of the beam could be used sufficiently.On the basis of the predecessors’ theoretical research on double composite steel and concrete crack width, the main contents of this dissertation is to consider different parameter values for double composite girder crack. To establish a simply supported beam by reverse load is to simulate the negative moment region. Considering the slip between steel bar and concrete and the slip between concrete slab and steel beam, not to consider the shrinkage and creep of concrete, the tensile fracture of concrete without considering its compression fracture. Considering concrete slab on concrete cover thickness and the longitudinal reinforcement ratio of two parameters, by respectively using different parameter values more groups of finite element model is established, the analysis of these two parameters of steel and concrete double composite continuous beam crack spacing and crack width in the negative moment region.Test results show that, in the steel and concrete composite continuous beam,under the condition of other conditions, the greater the concrete slab thickness of concrete cover, the greater the composite beams on the surface crack width and the crack spacing. The greater the longitudinal reinforcement ratio, the smaller the fracture spacing and the crack width. It obtained by finite element software simulation analysis of the maximum crack width calculation results than formula of crack width limits in concrete structure design specification, this phenomenon is mainly due to considering the relative slip between steel girder and concrete plate and slip between reinforcement and concrete, the shearing slip selection of constitutiverelation and the assumption of shear sliding section have very big effect on the crack width...