The New Beam And The Old Plate Composite Component Of The Bending Performance Research

The old city reconstruction is the hot issue of common concern to the government. In view of the protection of old buildings, the planning department often asks "repair the old as sweet", don’t change the original style of the building, but the use function of internal should along with the economic development needs to be changed, which requires the structural engineers to reform the original structure in reasonable way. Wide column double beam frame structure system is a new concept of system transformation, the reform of the housing in recent years the wide application, it can be widely used in masonry structure and concrete structure in the transformation such as residential, hotel, hospital, especially apply to little space into a large space of old buildings.In the process of masonry buildings reform, the new casting beam can very good coordination with the old panel is the important way to ensure the entire structure work together well, design the connection between the two in reasonably way, can ensure that both the new casting beam and old building panel coordination work together. Although many scholars studied the composite beam stress performance, and puts forward the relevant design Suggestions, the scholars have paid no attention to the new beam mechanical characteristics of the old plate composite components at home and abroad. Reasonable to consider new beam the stand or fall of the whole of the old plate composite components are connected to the bearing capacity of contribution will directly affect the ductility design of "strong column weak beam" and "strong shear weak bending" method. Therefore, it is necessary for systematic study of new old plate beam system on the bearing capacity of the composite components.Based on the national natural science fund project Research on Flame Structure System of Double Reinforced Concrete Beam and Wide Column in the Old Masonry Underpinning Reconstruction, Item Number:51278445, design made seven test artifacts, including six component is the same composite form but there are differences between the shear pieces of spacing and arrangement of new beam old plate composite component, the other one is contrast beam, in the form of reinforced concrete t-beam; Six reinforced concrete composite components are used to observe different shear a layout spacing and different shear connection form about the development of crack and the influence of the bending performance.This article around the different shear a layout spacing and different shear connection form of new old plate beams affected by the bending properties of the composite components, main work is as follows:1.New beam old plate composite component of the bending performance of research, including:failure mode of cracking moment, on both sides of the form and development regularity of cracks, the stiffness characteristics of ultimate bending moment, etc., and compared the theoretical calculation of t-beam concrete;2.New beam old plate composite component of the load and the deflection curve of the research, and compared with t-beam concrete, analyze the ductility performance of composite components;3.Analysis of static load test results, the different shear a layout spacing and different shear connection form of new old plate beams flexural bearing capacity of composite components, set up new beam old plate bearing capacity calculation formula of composite components.The research results show that the new beam failure mode of the old plate composite components and the deflection curve, the crack law of development similar to reinforced concrete concrete T beam; Adding reinforced concrete shear and concrete shear parts of the two forms of cut pieces in the main role is to make the new casting girder and the original old board to the deformation coordination of work; After the old and the new beam plate composite formed a new composite component, the original old plate can be used as part of a new composite components together with the new casting of beam forming force, this article puts forward the design method can be applied to the actual reinforcement renovation project; The ductility of the composite component performance can satisfy the seismic basic requirements; In this paper, the calculation method of ultimate bearing capacity of composite components results agree well with the test results.