Progressive Collapse Behavior Of Steel Frame With Infilled Wall

The fundamental task of structural analysis and design is to ensure the safety of buildings, in the world today, frequent building bomb attacks, collision event and terrorist attacks has caused heavy casualties and property losses because of building collapse, which results in higher demand on preventing the structure from collapse under the loads of accidental or earthquake.In recent years, the fabricated steel frame has become the perfect structural form of promoting the development of housing industry due to advantages of lightweight, good seismic performance, a high degree of industrialization ,green. And the form is bound to replace reinforced concrete structure as main form. Studies have shown that the existence of infilled wall reduce the steel frame deformation, and can help improve the structure of the stiffness and bearing capacity. However, the traditional structure design approach don't consider the effect of infilled wall, and the lack of analysis of progressive collapse behavior of steel frame with infilled wall. In the view of this, the progressive collapse behavior of steel infilled frame are analysed from theoretic and finite element simulation, and put forward practical simplified model for the frame, and use the simplified model to analysis the whole PC resistance performance of building structures. The main duties include the following aspects:(1) Based on the existing theory and test results, the load-deformation formulae corresponding to the mechanical model for planar steel infilled frame with composite beam was proposed and the mechanism of substructure in the collapse process was studied.(2) ABAQUS software is used to verify progressive collapse planar steel frame with composited beam test, steel frame with infilled test,steel frame with ALC infilled walls, multi-story and multi-span frame structure test. The application of the modeling approaches testifies the accuracy and applicability. The models introduced in this paper are modeled with constitutive relation of the materials, element type, contact relation model and determination methods of their parameters which adopted in model verification. The finite element model of planar steel infilled frame with composite beam was created, and the distribution of internal force and load-displacement curves of failpoint under vertical load was analyzed. The FEM results were used to evaluate the accuracy of analytical results.(3) Based on infilled wall equivalent single strut model, finite element model for masonry lightweight blocks and embedded wall panel were established, and the effective width formula which are applicable to masonry block and embedded wall panel steel frame under column loss,has been re-fitting on a fine cross aspect ratio of basic parameters,and we have a parameter analysis of the calculation formula of effective width influence.(4) Based on alternate load path method and time history analysis method, with and without infilled wall frame equivalent model are analyzed under progressive collapse. The effect of infilled walls on frame was studied by the following indexes: vertical displacement of column failure point, change of the internal forces of structural members and structural anti-collapse capacity. By the above study it can be found that the existence of infilled wall can better improve the structural anti-collapse capabilities.