Seismic Behavior Researches On Concrete Structures Of Tall Building With Transfer Slabs

This dissertation focuses on researching into the effect of earthquake-resistant behavior due to the transfer floorslab cast-in-site in the tall building structures. The ratio of story-drift of the stories above and below the transfer slab in the Structure with Transfer Slabs (STS) is proposed to control the acute transformation of lateral deformations and the assignment of earthquake shear forces on the stories adjoining the transfer-story. The main achievements of this dissertation are expatiated as the following.(1) Studying the acute transformation of story-drifts, the assignment of story shear forces and the pipeline of forces of the stories adjoining the transfer slabs affected by the different ratios of equivalent lateral stiffness of the stories above and below the transfer slab. Based on this, pointing out that the ratios of equivalent lateral stiffness couldn't control effectively the acute transformation of story-drift of the stories above and below the transfer slab, thus the design concept of the ratio of story-drift between the structure above and below the transfer story is brought forward. This paper provides the referential values of the ratios of equivalent lateral stiffness and story-drift in the regions of seismic intensity 7.(2) Pointing out that with the increase of altitude of the transfer floorslab, the restricting effect of the ratio of equivalent lateral stiffness is more limited and some seismic performance of STS differ from the existing theory on the structures with transfer beams, based on analyzing the influence of the level of transfer story on structural dynamic properties and earthquake action effects of STS. The dissertation indicates it is imperative to adopt the limitative conditions more rigorously of the ratios of equivalent lateral stiffness and story-drift in STS with the higher transfer story.(3) Probing the influence of thickness, mass, and stiffness of the transfer floorslab on the aseismic performance of the global structure, and the regularities of deformation and stress distribution in the transfer floorslab that are the objects of research. The analytic results indicate that the thickness, mass, and stiffness of the transfer floorslab are changed relatively less, their influence on lateral displacements and earthquake shear forces are less obvious, but the influenceof horizontal earthquake response on the deformations and stresses in the transfer floorslab are more obvious in the regions of seismic intensity 7.(4) Expatiating upon the influence of three kinds of transfer structures, namely the tall building structures with transfer slabs, transfer beams or trunk transfer beams, on the natural periods of vibration, vibration modes and earthquake responses of these structures and pointing out that some seismic performance of the structure with transfer beams are not more superior to the other two transfer structures, by analyzing comparatively the seismic performance of these three structures. Based on the research on the influence of different finite element modes of floor slabs upon dynamic properties and earthquake action response of the whole structure with transfer beams, the hypothesis of elastic slabs should be chosen to analyze the high-rise building structure with transfer story.(5) Analyzing the structures with transfer slabs or beams using the pushover analysis method, in order to comprehend the failure mechanism, ductility, and aseismic performance of the structures.Generally, the breakage mechanism of mixed hinge of beams and columns will take place in the structures with transfer slabs or beams.(6) Putting forward the seismic checking computation methods and corresponding seismic fortification measures for the design of the STS by combining the theoretical analyses.Based on the achievements mentioned above, STS will characterize a better earthquake-resistant performance in the regions with fortification intensity 7 as long as the limitation of ratios of equivalent lateral stiffness and story-drift is controlled within the ex...