Structural Reliability Of Beam String Structure Considering Random Load Ratio And Conservative Design Psychology

Prestressed beam string structure,as a new type of space structure,in recent years,it has been widely applied in engineering practice due to its light weight,high bearing capacity,good space utilization and beautiful and smooth architectural image.So far,many experts and scholars at home and abroad have carried out a lot of basic research work on the mechanical performance,calculation unit,design method,construction process and development and application of prestressed beam string structure,including the analysis and research on the bearing capacity and reliability of beam string structure.In these existing research results,it can be found that most of the research is based on the fixed load ratio criterion,while ignoring the load ratio randomness,which is an important factor in the design of beam string structure bearing capacity.In addition,some research results show that when the half?span load has a negative impact on the bearing capacity of beam string structure,if the beam string structure is designed according to the current partial load coefficient,the safety of the beam string structure will be low,and the phenomenon of conservative design is common in practical engineering.Based on this,in order to further analyze the beam string structure to ensure its safety,this paper carries out the reliability analysis of the beam string structure considering the random load ratio characteristics and conservative design.The main work is as follows:(1)Using the finite element analysis method,the variation law of the ultimate bearing capacity of the beam string structure is obtained,and the variability of the ultimate bearing capacity of the beam string structure under the fixed load ratio and the random load ratio is compared and analyzed.It shows that the randomness of the load ratio has an important influence on the variability of the ultimate bearing capacity of the beam string structure.(2)Based on the simplified method,a more realistic limit state equation of beam string structure considering the load random characteristics is established.The reliability analysis of the whole bearing capacity is carried out by combining finite element method and Monte Carlo algorithm,and the accuracy of this method is verified.The result of reliability analysis shows that the reliability index obtained by the fixed load ratio criterion is a little higher than the actual situation.(3)By using the method of questionnaire survey,this paper analyzes the possible influence on the structure design from the psychological aspect of the designers,and then draws some reference conclusions for the design of beam string structure.(4)Considering the stochastic characteristics of load ratio and conservative design,the reliability analysis of beam string structure is carried out.The results of reliability analysis show that the beam string structure with random load ratio and conservative design also can be safely and reliably used in practical engineering.