Study On The Mechanical Performance Of The Modern-Bamboo Top-Bear Arch Bridge

With the development of society,the engineering has higher request to the sustainable development,It is getting inevitable to seek new material as replacement of the traditional building material.bamboo arch structure is a successful new material experiment.it makes a perfect combination between compression performance of glued laminated bamboo and characteristics of arch bridge.Researching bamboo arch structure is supposed to be a great significance.This paper demonstrates the development of modern bamboo material and arch bridge structure,and use a 16 meters the Modern-Bamboo Top-Bear Arch Bridge as the research object,Analysed it's the static and dynamic analysis through changing rise-span ratio arch deflection,width-span ratio.The details are as follows:First of all,this paper expounds the current situation of modern bamboo materials,makes a mechanical analysis on structure of arch bridge and points out the possibility of theory about building the Modern-Bamboo Top-Bear Arch Bridge.Based on this,make a finite element analysis on 16 m Modern-Bamboo Top-Bear Arch Bridge.constitutive relation of Modern laminated bamboo ? input of the load are certained in the finite element simulation.Analysis on the static characteristics of the ultimate bearing capacity of the modern bamboo arch structure,the conclusion is that the stress,axial force and vertical deflection and so on are all satisfied with the requirement of the standard.Through analysing the influences of arch moment,axial force,deflection and force of supports etc.the reasonable rise-span ratio of modern has been discussed.and different stiffness of arch bridge has more influence on structure stress and deformation value of the Modern-Bamboo Top-Bear Arch Bridge,arch stiffness is the critical factor of structure has come to a conclusion through changing different stiffness of bamboo arch width and height.Secondly,the modal analysis of the arch bridge structure is carried out,and the ten order natural frequencies and corresponding modes are obtained.By changing the structure rise-span ratio,width-span ratio and arch stiffness parameters researching dynamic characteristics of modern bamboo bridge,study shows:(1)the change of the rise-span ratio of the bamboo arch bridge has the change of the first two order modes of the structure,which is different from the traditional steel tube concrete archbridge;(2)modern bamboo arch bridge with the rise-span ratio decreases,the range of the fundamental frequency variation come to be different,the ratio of the rise to span ratio should not be too large,when design the modern bamboo arch bridge;(3)The ratio of the transverse frequency and vertical frequency of the arch is increased with the increase of the width of the bridge deck;(4)the high order frequency of the structure of the bamboo arch is decreased while the the ratio of the width is increased,the higher the order number,the more obvious the decreasing trend.Through the analysis of sagittal cross comparison arch stiffness and arch axial force,moment of arch ring,bearing reaction force and effect,discussion of a bamboo bridge structure and reasonable rise span ratio;through from change bamboo arch rib width and height of the structure is simulated with different stiffness,a conclusion is drawn that different stiffness on the bamboo bridge vertical deflection and arch rib should influence bigger,arch rib rigidity for the structure factors.Finally,the seismic performance of the modern bamboo arch bridge is studied by using time history analysis,and the displacement and internal force response of the three kinds of seismic waves are obtained.The parameters were analyzed by changing the rise-span ratio and stiffness.as follows:(1)the rise-span ratio of the modern bamboo arch bridge has great influence on the lateral displacement of arch,and the influence become bigger when the ratio of rise to the rise-span ratio is increased;(2)with the increase of the ratio of the stiffness,the change of the transverse direction of the bridge(curve slope)is decreased,the bending stiffness of bamboo arch need to be set reasonable and should not be too small when design the structure.