Research On Effect Of Mechanical Performance Of High Strength Semi Lightweight Concrete On Concrete-filled Steel Tube Arch Bridge

High strength semi lightwight concrete is a kind of concrete that is configured with the right amount of ordinary aggregate materials in the light aggregate.High strength semi lightwight concrete has both high strength high normal aggregate concrete strength,stiffness big,carrying capacity is strong,the advantages of but also solves the problems of easy cracking and low ductility.Concrete-filled steel tube as a new type of composite material,belongs to the composite structure of steel and concrete,this kind of composite structure can make full use of steel tube and concrete their advantages,these two kinds of material so the Concrete-filled steel tube structure under the action of axial force bearing capacity than two separate from the sum of the bearing capacity of the load.This paper combined with the structure and material properties of bridge bear loads and the actual situation,using the spatial finite element analysis theory to establish the model of combination of High strength semi lightwight concrete of lightweight,high strength,excellent characteristics,such as volume,stability and durability,compare different schemes of concrete,analysis the stress and stability of the bridge structure and natural vibration characteristics,then prove that high strength time light on the mechanical behavior of Concrete-filled steel tube arch bridge of concrete to improve.The main tasks of this article include the following:(1)The combination of High strength semi lightwight concrete present research status at home and abroad,horizontal compares it with high-strength normal aggregate concrete and high strength of the difference between light aggregate concrete,and summarizes their engineering application and research.Paper also introduces the characteristics and current situation of the development of the basic structure of concrete filled steel tube arch bridge,put forward High strength semi lightwight concrete used in the construction of Concrete-filled steel tube arch bridge to improve its mechanical properties.(2)Based on the spatial structure finite element analysis,the spatial finite element model of a large span Concrete-filled steel tube arch bridge is established in the background of a bridge on the Yangtze river.And on the bridge,with the method of linear elastic static analysis into bridge stage and construction stage the stress variation in the arch ring of each location.The study shows that the stress of the steel tube components and the inner fill concrete in the concrete arch bridge of the steel tube is improved by the High strength semi lightwight concrete,which makes the stress of the steel tube and the concrete in the Concrete-filled steel tube arch bridge.(3)According to the characteristics of Concrete-filled steel tube,the basic theory and the first type of instability of the arch bridge stability problem are combined the characteristics of the phenomena are given and compared with three different kinds of concrete perfusion schemes.The results of analysis can conclude that the High strength semi lightwight concrete can improve the stability of the Concrete-filled steel tube arch bridge.(4)This paper carries on the analysis of the self-vibration characteristics in the phase of the bridge stage,and obtains their vibration period and the name of the first third order.The results show that the natural frequencies of the different infusion solution is generally low,so the density of concrete and the change of elastic modulus of structural natural frequencies.