The Coupled Shear Wall Directly Displacement-based The Seismic Des1gn&Experimental Study

In recent years, with the rapid development of the our country economy and the acceleration ofurbanization, the big and medium-sized cities appeared the phenomenon of and shortage in all over thecountry. In order to alleviate land tension and make full use of the space resources, including a largenumber of tall buildings and ultra-high buildings has appeared the construction all over the country. So, themore and more shear wall structures had applied in modern architecture, which the most common types ofstructure are shear wall, frame-shear wall structure, the core tube etc. The method of seismic design is stillbased on bearing capacity or based on force in our country. Its core thought is three-level fortificationthought. Although the above-mentioned method can guarantee the damage degrees of the building structurein a certain under the action of earthquake damage, which controlled in the set range. The statistics ofmodern earthquake disaster show that although the extent of damage of the building structureis not big. But for reasons that the direct and indirect economic loss caused by such the largerstructural deformation is great.The original method based on bearing capacity of the seismic design can not meet theever-increasing needs of people recently. In order to meet the increasingly needs of people, anew seismic design method should be searched out. On this occasion, the paper applied theperformance-based method of the seismic design to design the aseismatic design of shear wallstructure. The performance-based method of the seismic design include several kinds ofspecific design method. And the paper mainly studied the method of the shear wall directlydisplacement-based the seismic design.Firstly, this paper introduced the development process of seismic design method forbuilding structures. In the this part, the paper focused on the principle and steps of the directlydisplacement-based seismic design mehtod.In order to improve the ductility, deformationcapacity and energy dissipation capacity of shear wall, the paper proposed a new stirrup form —and it is a subsection closed stirrup form, which based on the form of traditionalreinforcement. And a section of casing protected pipe was lassoed the end of the verticalstrees in shear wall.In order to validate the earthquake resistant performance of the shear wall be placingstyles of steel bars and the added casing, this paper made a pseudo-static experiment for thespecimen. According to the analysis and the comparison of the experiment and other relatingdocuments, the paper drawn the below preliminary research results.(1)The Segmentation closed stirrup can improve the confined effect from hoop steel forconcrete. And it made the steel begin cracking and shedding when concrete had a largedeformation. The segmentation closed stirrup can make the adjacent stirrups form the wholeinteraction. Thus, the form of steel in concrete restriction had a better effect than traditionalstirrup. Because of the better effect of the concrete constraints, it made the ultimatedeformation and the ultimate bearing capacity of shear wall have been improved. That is tosay the shear wall had a large plastic deformation. Accordingly the ductility and theearthquake resistant performance of shear wall had been promoted. Through the analysis andcomparison with the trial data of domestic similar trial, the result showed the proposed newform of stirrup has a better constraint function, and the earthquake resistant performance ofshear wall had some degree of improvement.(2)The shear wall, adding casing pipe for reinforcing bars, obviously had a great ultimate deformation.Added the casing pipe at the end of shear wall longitudinal force, it can form a local unbonded concretestructure at the end of shear wall. So, the steel can play a better role for the later stress of the shear wall.Since the unbonded effect from the reinforced concrete, it made the concrete will not be severe cracked orspall after the concrete cracked. Consequently, it makes the final damage of the concrete lighter, and it willchange the destruction state of the concrete in a certain extent. The observation and analysis of the testphenomenon can conclude that added casing pipe for concrete will have a lesser degree damage than thosedidn't. (3)The result of experiment obviously showed that the improved shear wall had a full and smoothhysteretic curve. And the energy intensity of the improved shear wall was better than others. Ductility ofthe shear wall is strengthen due to innovation of the proposed stirrups banding form and adding casingat the the ends of longitudinal reinforcement of the shear wall. Therefore the aseismicity of the shear wallis preferably, as the hysteresis curve is fuller and the area of hysteresis loop is greater than the hysteresiscurve of other shear wall. Finally, the earthquake resistant performance of the shear wall is enhanced, andthe energy dissipation capability is increased when encounter earthquake.In order to further study the deformation characteristics, the order of occurrence and thedisplacement of structure for shear wall in function of earthquake, the paper applied theEPDA module of the PKPM software to static elastic-plastic analysize (Push-over analysis)the frame and shear wall structure. Layer displacement of each floors of the entire building inthe earthquake can be more intuitively observed by the graphical output, as well as find thefloor which the maximum displacement directly. The location and order of the plastic hinge ofthe whole building can observed by repeated analysis. Displacement of any node of eachfloor can easily find by the structure output of pushover analysis etc..