Local Buckling Analysis Of Various Shear Walls With Elastic Constraint

In recent years,the frame-core wall structure system has been widely used in the high-rise buildings and advance core wall construction becomes a common construction technology.The local stability of the core wall is the key factors that limit the story of advance core wall construction.At present,few studies have been carried out to the local buckling of core wall when core tubes constructed in advance of the frame.Technical Specification for Concrete Structures of Tall Buildings(JGJ3-2010)in China does not specify the local stability of the core wall when core tubes constructed in advance of the frame.And in the JGJ3-2010,the elastic restraint from the flange and the web has not been reasonably accounted for the local stability of the core wall.In this paper,the elastic buckling of various section shear walls under non-uniform compression were detailed and comprehensive analyzed by using the Ritz energy method and finite element method.The calculation formula of buckling coefficient of various section shear walls were presented,and achieved good results in the practical engineering.After the analyses of the local stability of shear wall in the JGJ3-2010,the limitations of the JGJ3-2010 were summarized.The elastic buckling of the rectangular plate under non-uniform compression with different boundary conditions was analyzed by using the Ritz method and finite element method,including plate with all four edges being simply supported,with two opposite edges being simply supported and clamped,with three edges being simply supported and the rest edge being free and with one opposite edge being simply supported and the rest opposite edge being clamped and free.Based on the different codes,calculation formulas of buckling coefficient of rectangular plates were presented which is applied to concrete.Elastic buckling of web plate of T-section under non-uniform compression was analyzed by using the Ritz energy method and finite element method.The difference between the rotational spring restraints and torsional stiffener restraints is pointed out.A parameter correlating the torsional stiffness of the flange and the bending stiffness of the web was introduced to quantify the restraint from the flange to the web plate.A simple and accurate formula for the buckling coefficients of the web plate of T-section restrained by flanges was presented.Elastic buckling of web plate of unsymmetrical T-section was investigated based on the above research,and a calculation formula for the buckling coefficients of the web plate of unsymmetrical T-section was put forward.In addition,a reasonable reduction factor was introduced to represent the difference between the buckling coefficient of web plate of L-section and the buckling coefficient of web plate of T-section.An explicit expression for web plate of I-section under non-uniform compression was deduced by using Ritz energy method.A simple and accurate formula for the buckling coefficients of the web plate of I-section restrained by flanges was presented by using finite element method which had the same expression form with T-section.Elastic buckling of web plate of unsymmetrical I-section was investigated based on the above research,and a calculation formula for the buckling coefficients of the web plate of unsymmetrical I-section was put forward.In addition,a reasonable reduction factor was introduced to represent the difference between the buckling coefficient of web plate of C-,Z-section and the buckling coefficient of web plate of I-section.Elastic buckling of flange plate of T-section under uniform compression was analyzed by using the finite element method,and the results show that the flange of T-section can be simplified into the corresponding flange of L-section.For the two flange plates of unsymmetrical T-section,only the flange with lager width should be considered.Different from the aforementioned plate of various section,the I-section flange is constrained by a rotational spring restraint from the web.An explicit expression for flange plate of I-section under non-uniform compression was deduced by using Ritz energy method.A simple and accurate formula for the buckling coefficients of the web plate of I-section restrained by flanges was presented by using finite element method.For the flange plates of unsymmetrical I-section,each flange should be considered.In addition,the rotational spring restraint stiffiness of the flange plate of C-,Z-section was double that of the:flange plate of I-section.