Research On Performance Improvement And Renovation For Existing Building Of Brick-concrete Structre ↑

There are existing 56 billion square meters construction area in our country,of which a large proportion of brick and concrete structure were built in 60 s and 70 s of last century.It is difficult for the existing brick and concrete structure to meet the seismic requirement of current standards.However,the construction of this kind of building is pretty wide.The reasonable renovation is constructed,which can realize its function and safety as well as can avoid the waste of resources and the repeated input of productive forces.Moreover,the existing land and construction resources are effectively used,which can create huge economic benefit and social benefit.To solve these problems,researches are conducted as follows:(1)According to the existing theories,motivation of the renovation and the target,rational renovation strategies and methods are proposed and developed in this paper by assessing the value of reconstructing and reusing these buildings.It was clarified that the value of renovating building should be took full advantage with a low cost.Then a reasonable method of improvement and renovation is introduced.(2)An interior-frame brick-concrete structure is taken as an example in this study.The failure mechanism of frame beam-brick external wall joints is detailed analyzed by ANSYS finite element software.The results show that under the action of earthquake,the failure of shear strength at the interface between the brick and the outer wall causes the separation of frame beam and wall and the failure of the joint.In order to avoid such damage,the proper transformation of the original building plane is put forward,which changes the structural system into the frame structure and transforms it into the design method of the residential building based on the method of changing the force path.The method of strengthening the cross section method to strengthen the frame beam and the brick wall is carried out to form the combined node and the composite column.The finite element analysis results of the joint behavior of the frame beam-composite brick column show that the reinforcement method not only satisfies the design principle of "strong node s and weak elements",but also ensures that the combined node can be used as the junction node to transfer forces and moments.(3)Under the action of earthquake,the damage degree of the multistory frame-brick concrete structures are more serious than that of the multistory brick masonry building.The finite element analysis software ANSYS is used to analyze the seismic behaviors and mechanical behaviors of before and after renovation.The results show that compared with before renovation,the structural bearing capacity and ductility increase and the maximum lateral displacements and the maximum story drifts decrease after renovation.(4)The insulation of the external wall is the biggest factor that affects the energy consumption in the construction and maintenance phase.Aiming to the problem that the traditional insulation method has poor insulation effect and insufficient durability,a new method of building the sandwich wall structure is put forward.Under the premise of keeping the wet exchange between the in and out of wall,this approach eliminates the traditional sandwich wall in the air layer settings,which can effectively improve the existing masonry structure of the energy saving effect.The renovating ideas and methods of basing on the conversion structure can provide a reference for the design and construction of similar projects.