Numerical studies of complex connections in the external tube system of New CCTV Building

Two kinds of finite element models of complex connections in the external tube system of New CCTV Building were investigated theoretically.Their strength state,seismic behavior and failure mechanism have been analyzed and estimated in accordance with the numerical results from finite element method.The effects of un-avoided brace eccentricities during loading process of test have been studied. An integral connection model was established which is composed of a loading frame with rigid beams and columns,a cross brace and a connection joint.The analytical objective of the integral model was to assess the additional effect of floor drift on connection behavior under cyclic loading,which hasn't been considered in advance in the early test.And the obtained numerical results can be used as the spread and supplementary parts of test.A two-floor structure from external tube of New CCTV Building which contains multiple complex connections has been analyzed under dead and cyclic load by using an elaborate finite element model.The conclusion drawn from the above numerical results and comparison between numerical and test results can be considered as the fundamental support and improvement to the design check and construction of New CCTV Building.