Research On Construction Control And Key Technology Of Composite Surface Of Steel-concrete Composite Beam Cable-stayed Bridge

Cable-stayed bridge is a structural system that is jointly supported by towers,beams,cables and foundations.Among them,the composite beams are one of the common girder forms commonly used in cable-stayed bridges due to their clear force,large stiffness and light weight.In this paper,the numerical analysis method is used to study the construction control sensitivity of the composite girder cable-stayed bridge.The main work contents are as follows:(1)Using Madis/Civil to establish a finite element model model of space beam element,the main beam self-weight error,cable tension error,concrete plate elastic modulus error and cable elastic modulus error are analyzed.The influence law of beam internal force,bridge line shape,bridge cable force and yaw tower deviation.The effect of unit initial tension on the displacement value of the beam segment is on average three times the effect of unit two tension on the displacement value of the beam segment.(2)The influences of the single-segment construction method and the double-segment method on the stress of the superposed beam cable-stayed bridge are analyzed.For the single-segment construction scheme,compared to the main beam when the wet joints of the bridge deck are first poured and the design strength is reached,and then two stay cables of the corresponding segment are poured,and the wet joints of the bridge deck are poured after the two stay cables are cast.The peak tension stress of the lower flange is more than 57% higher,and the compressive stress of the bridge deck is also larger.With double-segment cyclic construction,the peak compressive stress peak of the lower edge of the main beam is smaller than 26%,and the peak tensile stress increases less;The compressive stress of the bridge deck is slightly larger than that of the single-segment construction scheme.(3)The finite element model of the test specimen is established.Based on the experimental verification,the main factors affecting the shear performance of shear nails and the influence of common construction diseases on the shear performance of shear nails are analyzed.Shear nail diameter is the main factor affecting its shear stiffness and shear capacity.The strength of concrete and shear nail height have little effect on its shear stiffness and shear capacity;the inclination of shear nails exerts force on it.The performance has a significant impact.When the inclination angle is less than 20 °,the shear capacity of the shear nail is reduced by 24%.When the cavity is located at the root of the shear nail,the cavity has a significant effect on the shear capacity of the test specimen.After a certain distance from the root of the shear nail,the cavity has almost no effect on the shear performance of the shear nail.