The Research And Applications Of Safety Assessment For Carrying And Erecting Precast Beams

In recent years, in order to meet the needs of the rapid development of highway in our country, the methods of concentrate prefabricated in bridge construction become more and more widely. Although the construction scheme can greatly shorten the construction period, at present the theoretical study on safety assessment of girder transportation was relatively less, especially when transport and hypothesis beam slab under the condition of complex terrain, safety accident occurs frequently. This thesis depends on Hunan traffic science and technology plan projects, we did safety assessment of transport and erect beam under the condition of complex terrain, and propose practical support measures to improve the safety factor of such construction.In this thesis,Hunan Huaihua ring expressway bridge construction was used as the background. The research on theory application of safety assessment for carrying and erecting beams of precast beam panel was studied, Main work content is as follows:Firstly, based on a large number of field investigation and information query, a preliminary analysis of the present situation and level of research on this field at our country and abroad was made,which complete demonstrating the necessity and importance of the this research.Secondly, based on the risk theory to identify the risk factor of carrying and erecting beam,to determine the construction risk source,and extracting the high risk factor.What’s more,based on the finite element theory, using the large finite element software ANSYS to simulated analysis for high risk factor transportation beam under bare beams,acquiring the stress and strain of beam slab during process of transportation.Proceeding field experimentation and compared with the values of theoretical analysis, to test slab bearing capacity to meet the specifications under the various conditions.Then safety assessment of transport and hypothesis beam slab under the condition of complex terrain based on the reliability theory has been researched. By doing field investigation and statistical of the actual engineering, based on probability analysis, deriving probability model of structural load and resistance, applying failure probability equation to solve reliability during process of transportation and hypothesis beam slab.At last, proposing appropriate extrech measures for construction process of bare beams.The results show that risk factor analysis theory can be effective recognition for carrying and erection beam construction crane of risk source. Based on the reliability theory,combined with finite element analysis and experimental study,did safety analysis to high risk factors, determine the failure probability and verify the feasibility of the evaluation theory.By combining with engineering practice,analysis the risk of transport and hypothesis beam slab under the condition of complex terrain, selecting appropriate construction loads and structural resistance,combining deterministic with probabilistic analysis, analyzing security to the problem which may be a risk, according to results of theoretical calculation and experimental study,improving construction support measures to obtain great project benefit.