Study On The Mechanical Properties Of Members During The Construction Of Long-span Steel Truss

This Large-span steel truss has the advantages of light weight,good economy,high rigidity,good seismic performance,and diversified forms.Many domestic and foreign scholars have greatly promoted the development of large-span steel truss structures at home and abroad.In addition,steel truss installation construction technology and construction site monitoring methods are also constantly innovating.In order to ensure construction safety,it is important and necessary for the project to adopt finite element analysis and construction monitoring.Based on a construction project example of a standard parts research institute in Handan City,thesis uses a combination of finite element model analysis and construction site monitoring to study the stress changes of the long-span steel truss corresponding to the test members under two different construction schemes.By comparing the bar stress,node displacement and deformation,structural stability,and construction environment of the two construction schemes,the advantages and disadvantages of the two construction schemes are comprehensively analyzed,which provides a reference for the selection of construction schemes for similar projects in the future,and finally tests the law of member strain changing with time has been deeply explored,and the main contents are as follows:(1)When the single steel truss is hoisted,the most unfavorable member is the upper chord at the hanging point;After the installation of the steel truss is completed,the most stressed member is the upper chord at the mid-span.(2)During the overall hoisting construction of the two-stacked steel truss,the most unfavorable member is the secondary truss web member;after the installation of the twostacked steel truss is completed,the most stressed member is the upper chord of the secondary truss.(3)A comprehensive comparison of the two construction schemes in terms of stress,displacement and deformation,stability and operating environment found that compared with single-steel truss construction,the most unfavorable member stress is reduced by 50%when the two-steel truss is used for overall construction.%,the displacement and deformation are reduced by 90%,the stability coefficient is higher,the construction speed is faster,and the construction period is shortened.However,during the integral hoisting construction of the two-thrust steel truss,a lot of construction machinery is required and the construction site is large.However,the single-thrust steel truss is flexible in construction and has small site restrictions.The specific project should choose the appropriate construction plan to ensure the smooth completion of the construction.(4)Through the study of the law of the strain of the test bars in the two construction schemes with time,the type and the highest power of the strain curve fitting equation of the test bars are determined.In addition,the significance of the curve equation research and the method of use are introduced.It has very important guiding significance for the construction of similar projects.