Analysis Of The Effect Of Shear Lag Of Reinforced Concrete Core Walls With Mixed Concealed Bracings

The core walls structure of reinforced concrete is widely used in practicalengineering due to its outstanding mechanical behavior. Moreover, the core wallsstructure of reinforced concrete with mixed concealed bracing as one kind of newimproved form of ordinary reinforced concrete has its own advantages, such as highinitial stiffness, high bearing capacity and good ductility. However, the research andapplication is still not mature currently. Further study is not only the need of analysistheory development of high-rise buildings, but also the key to solving the practicalengineering problems. An important mechanical behavior of the core walls structureof reinforced concrete is that it has obvious shear lag effect and decreases the wholestructure function, which leads to that the material can not fully play the role and thesection design is not accurate. Further study on the shear lag effect of the core wallsstructure is necessary to fully understand the working performance of the core wallsand is the inevitable requirement of structural design optimization. In recent decades,computer technology and finite element technology has developed rapidly. Based onthe above background, this paper used ABAQUS software for finite elementsimulation and parameter analysis of reinforced concrete core walls.The paper makes researches respectively on reinforced concrete core walls andreinforced concrete core walls with mixed concealed bracing. It concentrates on rulesof distribution and development and influence factors of shear lag effect of core walls.The main works and achievements of this thesis are as follows:Firstly, this paper uses the finite element analysis software ABAQUS to simulatemodel of common core walls by finite element in reference [5]. The dissertationdiscusses the constitutive relation of concrete and rebar in the modeling process andthe selection of element type and mesh. After comparing the calculation results withthe test results and analysi ng the causes of error, it turns out that the ABAQUSsoftware modeling well simulate the mechanical properties of reinforced concretecore walls under monotonic loading.Secondly, this paper applies numerical stimulation method on reinforcedconcrete core walls with different structures, which researches on shear lag effect ofthe core walls by using the results of the longitudinal strain from the bottom flangesection of the calculation model. It defines the ratio of maximum longitudinal strainand the average longitudinal strain of flange section as "shear lag value", and the "shear lag value" can reflect the inhomogeneity degree of the longitudinal strain ofthe core barrel flange. Thus the shear lag effect of the core walls can be quantified. Itfocuses on the form of manifestation and change rule of the shear lag effect of thecore walls under the external force. This paper also discusses that what influence thecorner columns, coupling beams, distribution reinforcement and concealed bracinghave on the shear lag effect.Finally, this paper compared ordinary shear core walls with core walls mixedwith concealed bracing in the degree of the shear lag effect. It analyzes the shear lageffect of walls with and without openings in its wing wall s in the horizontalmonotonic loading process. The main contents of the study focus on the factors whichhave influence on shear lag effect of the core walls structure with mixed concealedbracing. These factors include the coupling beam height and the amount of sectionsteel, concealed bracing wall, concealed column.