Research On Safety Detection And Evaluation Method Of Long-span Suspend-dome Structure In Service

Long-span suspend-dome structure is a three-dimensional structure system which is composed of single-layer lattice shells,lower struts and cables,due to fatigue effects,environmental load,material aging,corrosion and other adverse effects of factors,the structure is easy to produce damage accumulation caused by the resistance decay,and even cause collapse accidents.With the continuous development of society,long-span suspend-dome structure projects blossom everywhere,the corresponding structural safety status detection and assessment of the work in the service phase more and more attention by the public and related scholars.It is an urgent problem to establish a safe detection and evaluation method for the long-span suspend-dome structure in service for China’s national conditions and science,also has important theoretical significance and practical value.However,the structural safety assessment of long-span suspend-dome structure in service based on structural safety testing is a complex system involving a lot of content to be studied.Based on the systematic analysis of similar engineering and related research,the research on the detection and evaluation of its structural safety is carried out to improve the accuracy and scientificity of safety detection and evaluation of long-span suspend-dome structure in service,the main research contents are as follows:(1)Research on security evaluation theory of long-span suspend-dome structure in service.Based on investigation and analysis of more than twenty cases about long-span suspend-dome structure in service at home and abroad,the definition and structure characteristics of suspend-dome structure is defined,combined with theresearch results at home and abroad,the existing problems and key contents to be solved are analyzed.Accordingly,from the perspective of theoretical mining,the impact factors on safety of long-span suspend-dome structure are analyzed.On the base of the current space grid structure design theory and through the analysis on load model and resistance model and its failure mode of long-span suspend-dome structure in service,the safety control model,control parameters and calculation method of long-span suspend-dome structure in service are obtained,and appropriate detection and evaluation procedures are developed.(2)Research on security detection method of long-span suspend-dome structure in service.Based on analyzing the structure of the sensor layout theory,to determine the detection,location,project selection as a starting point,with comparison of sensor placement optimization criteria and common methods,a sensor placement method of long-span suspend-dome structure in service basing on the combination of damage identification and global damage identification is proposed.Taking “Dalian gymnasium" which is the world’s largest span of suspend-dome roof(145 x 116)as an example,a set of structural sensor placement scheme of long-span suspend-dome structure in service with 128 sensors which is suitable for the structure form is calculated.Finally,the validity of the sensor placement method is further verified by comparing with the numerical simulation.(3)Research on safety damage identification method of long-span suspend-dome structure in service.Through the analysis of the structural damage identification method of long-span suspend-dome structure in service,by taking finite element model updating theory as the starting point and combining the correlation criterion of relevant finite element model,a modified method of safety finite element model for long-span suspend-dome structure in sercice is proposed which is based on measured data.Through the example,combined with the measured data of the sensor,the finite element model correction process was analyzed,obtained the consistent target model that consistent with actual situation.Based on the modified target model,the numerical analysis of the different load conditions of the structure is carried out.The structural damage and the damage results are obtained under different working conditions.The reliability of the modified model is further verified.(4)Research on safety evaluation method of long-span suspend-dome structure in service.Dividing the importance level of the main force component on power transmission path(the core components main)and on the analysis of the matter-element extension method on the basis of comprehensive evaluation theory,with safety detection method and damage identification method based on the research conclusion of long-span suspend-dome structure in service,a safety assessment index system which suitable for safety assessment of long-span suspend-dome structure in service is build and the index weight is calculated through combination weighting method,the weight distribution coefficient among the factors is determined quantitatively.The safety assessment model of long-span suspend-dome structure in service that based on matter-element extension theory is established.Finally,making an evaluation about the structure of the situations under different load condition to Dalian municipal stadium by example and verify the operability of the model.