Research On Behavior Of A Power Plant Boiler Of Concrete-filled Steel Tubular Frame To Resist Progress Collapse

With the development of economy, the demand for electricity increases evidently. It is necessary to build some large thermal power plants. Establishing the million kilowatt tower boiler will become a major construction project. By using the CFST members, the amount of steel can be reduced significantly comparing with steel frame columns. It can bring considerable economic benefits. But buildings which collapse in a progressive way may lead to a large number of deaths, injuries and serious loss of properties, so since the gas explosion which was resulted from the Ronan Point apartment building collapsed in1968, Researchers attached great importance on the structure design method of continuous collapse resistance.They had done much research in the performance and design methods of the structure on this issue in the past50years and made considerable achievements. The representative of GSA2003code and DoD2010code for progressive collapse standard were constantly perfect, and widely used. The studies of progressive collapse in China started later. There was no perfect methods to design and process. Previous studies had been attracted into steel structures and reinforced concrete structures, fewer attention was paid on giant steel tube concrete frame structure. Therefore, in this paper, it is very necessary to provide a good reference for concrete engineering practice through the research of using alternate path method for progressive collapse of a transfinite steel concrete composite frame. So studying deeply on the structural progressive collapse to perfect the design code in China has a vital significance. The main research is listed as followed:(1) At first, the model designed as a steel frame-brace structure with most of bar initially determined based on past experience. The elastic design was done in software STAAD/Pro. In order to reduce the amount of steel and obtain ideal economic efficiency, we change structure model of steel structure for the CFST structure by flexural rigidity conversion. The reasonable huge CFST frame-brace structures get finally.(2) According to the system of structure analysis, the element types for concrete-filled steel tubes, steel beams and steel braces are selected. And the rational constitutive model and failure criterion are used. The finite element models are validated by comparing with available experimental results.(3) The huge CFST frame-brace structures is established by the software ABAQUS. According to the actual situation of the project and GSA2003code and DoD2010code relevant norms, the angle column and the middle column of the main frame on each layer of different parts are removed. The progressive collapsed model analyzes by using the alternate path method of nonlinear dynamic analysis. The joint displacement variation tendencies above the removing column and other components internal force around the removed column are investigated. Then the progressive collapsed resistance is predicated.(4) The capacity of progressive collapse evaluates by DoD2010code and GSA2003code. The Linear static analysis of the model is carried on. As an example of the first layer of the main frame column structural failure, the calculation method of amplification factor is given. The specific displacement amplification factor is got. Finally progressive collapsed resistance measures of the structure are put forward.