The Influence Of Vertical Loads On Sidesway Of Tall Building Structures

With the deep development of the research work, the calculation and control of lateral deformation of tall building structures become more and more important. However, the influence of vertical loads on the lateral deformation of tall building structures is neglected in many commercial computer softwares or only factors, such as the effect of P-â–³, which increases the lateral deformation, is considered when the lateral deformation is calculated. In fact, it can restrain crack developing, increases section stiffness of vertical elements and decreases lateral deformation of tall building structures.But those are always not considered. Thus, the calculated values of lateral deformation are not accurate and it affects the designs, when they are controlled by the lateral deformation.Based on a great number of literature, research works have been done as follows:(1)10 reinforced concrete cantilever columns were tested. The influences of vertical loads on lateral deformations are recorded and discussed.(2)A simplified formula of section stiffness on RC compression-bending members is proposed, which shows the effect of vertical load to section stiffness of RC compression-bending members.(3)Using the simplified formula proposed above, lateral deformations of some reinforced concrete columns are calculated. The calculation results coincide well with the test ones. The formula is applied to the calculation of gravity second order effect.(4)Based on the formula recommended by professor Wang Chuanzhi and the test results at home and abroad, a theoretical formula of section stiffness and the calculation method of lateral deformation on reinforced concrete compression- bending members are proposed.(5)The influence of vertical loads on RC frame structures is analyzed. Curve features of story displacement with different vertical loads are carried out. The influence degree of different factors to lateral deformation under vertical loads are compared. And blind spot of basic commercial computer software in deformation calculation is pointed out.(6)The influence of vertical loads on RC frame-shear wall structures is studied. A suitable model of equivalent column is established by considering the effect of shear deformation of shear walls, and the results of wall element model and equivalent column model are compared.(7)The influence of vertical loads on RC frame-supported shear wall structures is discussed. Comparing the advantages and disadvantages of different equivalent column models, and considering the effect of shear deformation of shear walls and transfer beams, a new equivalent column model for RC frame-supported shear wall structures is proposed. Similar results have been gotten after comparing this model and wall element model.(8)The influence of vertical loads on push-over analysis of tall reinforced concrete structures with transfer story is researched. A tall structure with transfer story designed by the author is analyzed through push-over method and the influence of vertical loads on lateral deformation is or is not considered.(9)The experimental and theoretical study indicates that the effect of vertical loads must be considered when lateral deformation of RC tall building structures is calculated.