Analysis On The Mechanical Behaviors Of Reinforced Concrete Tube In Tube Structure And Spandrel Deep Beam

With the constant progress of science and technology and the needs of considering land saving in the city construction, the height of high-rise building structure is increased continually, the framework, shear wall and frame-shear wall which composed by the plane resist lateral force structure cannot satisfy the strength, stiffness and ductility requirements. Thus, tube in tube structure emerged as a new structural system. Because of work performance of tube in tube structure by the conventional structural plane components into the three-dimensional components, strong integrity and the formation of a large area of the column-free space between the inner and outer tube, so tube in tube structure has been a rapid development in the domestic and international tall building structures.At present, the theoretical study on the lattice type frame tube structure system much more, but theory research of the tube in tube structure is still not perfect; at the same time theoretical research of the spandrel deep beams is very few, especially the theoretical study on mechanical behavior of the spandrel deep beams is not enough deep. Engineering scholars generally believe that the design of spandrel deep beams is the same as frame structural beams. Based on the reinforced concrete tube in tube structure model and the spandrel deep beams of component models, the mechanical behavior of spandrel deep beam is analyzed, This paper mainly includes the following aspects:1、Through the external load, span to height ratio, the assumption of plane section and the design method are discussed, the mechanical characteristics of spandrel deep beams are analyzed. It can be seen that spandrel deep beams are different form ordinary frame beams, and also different form ordinary deep beams. Reinforced concrete tube structure spandrel deep beams subjected to the vertical shear and node bending moment based node force, while the ordinary deep beams subjected to external load on vertical load of node power, and in the practical engineering, spandrel deep beam span-depth ratio usually is between2-3, which the plane strain could be basically consistent with the assumption of plane cross section.2、Application of structural analysis and design software MIDAS/Gen for a given instance of tube in tube structure in elastic stage of the analysis. Discussing the variation of cycle, inter-story displacement angle, base shear, inner and outer barrel structure internal force distribution, shear lag effect. The results show that, the spandrel deep beam section height and width of the increase of tube in tube structure can enhance the whole performance, at the same time width effect on structure are not highly significant.3、Using general finite element analysis software ANSYS to simulate Analyse series of parameters.which can influence the performance of spandrel deep beams.By changing the reinforced concrete spandrel deep beams span to depth ratio,concrete strength grade, ratio of longitudinal reinforcement,and stirrup ratio, different fracture development, skeleton curve, stress distribution, bearing capacity and ductility are obtained, summed up influence law to mechanical properties of the spandrel deep beams.4、Using general finite element analysis software ANSYS to analyze floor slab reinforcement affecting mechanical properties of the spandrel deep beams of crack development, skeleton curve, stress distribution, bearing capacity and ductility.The work of this paper aims to study the spandrel deep beams of changing various parameters on the structure and mechanical properties of the spandrel deep beams,in order to providing references for research and design in future.