Study On Flexural Performance Of Cold-formed Thin-walled Steel-Reconstituted Bamboo Box Section Composite Beam

With the deepening of the concept of National Ecological Civilization Construction,green buildings have attracted more and more attention,and the steel-bamboo composite structure system was also developed in this period.In this paper,the cold-formed steel-reconstituted bamboo box-sectiom composite beam is a type of composite structure,which is made of two pieces of cold-formed thin-walled U-shape steel form the box section framework that bonding four pieces of reconstituted bamboo on the web and the top,lower flange.At present,there are only some scholars in China to study the mechanical properties of this new type of composite structure.Therefore,there is no industry standard.The research in this paper is a supplement to the steel-bamboo composite structure system.In this paper,the ultimate flexural capacity and failure mode of cold-formed thin-walled steel-recombined bamboo box composite beams are studied.Six models of steel-bamboo composite beams are established by using finite element software.The influence of initial defects of the model on composite beams is considered,and the corresponding single variable formula is put forward.Based on the experimental data of thin-walled steel-bamboo composite beam made by previous researchers.the correctness of the model and the research method is verified.and the ultimate bending moment and deflection of the composite beam are obtained by applying symmetrical concentrated load to the model.Comparing the ultimate moment value with the theoretical value of bending bearing capacity,the error was found to be too large,and then the strength reduction coefficient of reconstituted bamboo was modified to optimize the theoretical formula.The finite element model of composite beams are established by the factors such as span of beam,thickness of reconstituted bamboo,height and thickness of cold-formed thin-walled steel,span-depth ratio and depth-thickness ratio.The influence of different factors on flexural capacity is studied by simulation.By comparing the flexural capacity of composite beams simulated by various factors with the theoretical values calculated by the optimized formula,it is found that the errors between the two methods are small,which proves the correctness and applicability of the optimized formulas.Orthogonal analysis is used to obtain the optimal parameter combination factors of composite beam.The flexural capacity of cold-formed thin-walled steel-reconstituted bamboo box composite beam is estimated.The results show that the composite beams studied in this paper have better mechanical properties and integrity,and can be used as a bearing member in building structure.