Optimal Analysis Of Reasonable Finished State In Continuous Beam-arch Composite Bridge

Prestressed concrete continuous beam-arch bridge is widely used because of its beautiful appearance and novel structure.Continuous beam-arch composite bridge is a kind of structure with high degree of freedom,which is difficult to achieve a reasonable bridge state in the design and construction.Rigid beam and flexible arch bridge is necessary to make a systematic study on the optimization of the reasonable state,the determination of the suspender force and the tension of the suspender.This paper is based on a continuous-beam and arch bridge as the project,the optimization design of reasonable finished state,the following work is mainly carried out:(1)The structural stress characteristics of beam-arch composite bridge with rigid beam and flexible arch was analyzed.The method of determining the suspender force based on equivalent elastic support continuous beam was proposed.The calculation of the equivalent elastic support stiffness was described,and the initial suspender force was determined according to the relationship between stiffness and displacement,using MATLAB to optimize the suspender force.This method is simple and easy to operate.(2)The method of establishing the optimization model based on Yalmip matrix language and the MATLAB quadratic programming optimization method for the longitudinal prestress of beam-arch composite bridge were presented.The optimization of the longitudinal prestressed steel beam is transformed into a clear mathematical programming problem.And the process of steel beam optimization design was described in detail.This method has the advantages of simple and convenient operation,and can consider the stress constraint conditions in the construction stage.(3)The tension sequence of continuous beam arch composite bridge was optimized.The results show that the symmetric alternating tension can effectively improve the stress of arch rib with the order of suspender tension by the area of arch foot?1/4 arch rib region or 3/4arch rib region? vault area.It also can make the stress of the whole bridge structure in the construction process more reasonable and safe.According to the background of this beam-arch composite bridge,a new tension number was proposed.This scheme can reduce the construction period.