Advanced Materials Research Vols. 919-921

Abstract: The paper focused on the seismic performance of ceramsite concrete frame—shear wall, which conducted the modal analysis and elasto-plastic time history analysis for 6 layers ceramsite concrete frame—shear wall and ordinary concrete frame—shear wall by software SAP2000. Then compared the results, which showed that the periods of ceramsite concrete frame—shear wall structure was longer than the ordinary concrete frame—shear wall structure, while the inter-storey drift ratio and the maximum absolute acceleration are less than ordinary concrete frame—shear wall. Besides, the largest base shear of ceramsite concrete frame—shear wall structure was less than ordinary concrete frame—shear wall structure. And the seismic performance of ceramsite concrete frame—shear wall showed was better than ordinary concrete frame—shear wall structure.

Abstract: In China Wenchuan earthquake, the main characteristic of reinforced concrete frame structure is the weak layer yielding or collapse. Through the analysis of the stiffness change of the reinforced concrete frame weak layer during the whole process form the elasticity, yielding till collapse, the dynamic characteristics of reinforced concrete frame weak layer in the yielding and collapse processes were discussed. The lateral stiffness of the frame weak layer includes two parts: the lateral stiffness and the equivalent negative stiffness of column under the load action. It is shown that when the value of former decrease to the latter, the weak layer is in a collapse critical status. The frame weaker experiences form steady periodic vibration to variable periodic vibration then aperiodic motion. Some obvious chaos characteristics exist in the aperiodic motion in the plastic stage. It deserves further study to avoid weak layer collapse caused by the chaos motion.

Abstract: The equivalent linearization program LSSRLI-1, proposed by Xiaojun Li in 1989, is the important content in seismic zoning work and seismic safety evaluation of engineering sites. It is necessary to check the applicability of LSSRLI-1 to all kinds of sites. The mainly elaboration of this paper is verifying the applicability of seismic safety evaluation program LSSRLI-1 in stiff and half-stiff sites by exact solution. The results show that, it is well for both of them in most of the case, which is useful for the engineering practice.

Abstract: Nonlinear time history seismic analysis of Jinwan square No. 9 building under strong earthquake is made. Three dimension structural nonlinear analysis and performance estimate programme Perform-3D is used to establish the calculatrion model. FEMA beam, shear strength section are used to set up the frame beam element modal; Moment plastic hinge, shear plastic hinge and elastic beam section are used to set up the link beam element modal; FEAM column and shear strength section are used to set up the column element modal; fiber wall element is used to model the sheae wall. Performances of the structure under strong earthquake are analysed. Numerical calculation results indicate that the structure design satisfies the preestablished performance targets.

Abstract: The ABAQUS finite element software is used to simulate the horizontal mechanical behavior of steel frame-steel reinforced concrete lateral resistance wall structure and analyze influencing factors. The parameters include the steel ratio of shape steel infill lateral resistance wall, the axial compression ratio of frame columns and the aspect ratio of lateral resistance wall. The results show that the lateral stiffness and carrying capacity of structural system raise as the steel ratio of shape steel infill wall increase. With the axial compression ratio of columns increase, structural system has little change in the lateral stiffness, while the bearing capacity decreases and the torsional constraint for the frame columns is enhanced gradually. With the aspect ratio of lateral resistance wall reduces, the lateral stiffness and bearing capacity of structural system increase, while the ductility decreases gradually.

Abstract: According to the research data and achievements home and abroad, this paper puts forward the practical seismic design process and method of RC frame structure retrofitted by FRP, to promote the application of FRP in the field of RC frame retrofitting. And the ductility design of the column, the reinforcement design of the node area and the structures integral seismic action are discussed, providing a reference for future research and engineering application.

Abstract: Bottom frame-shear wall structure is a kind of special structure, due to the inharmonious relationship between the frame and masonry walls in bearing lateral capacity and deformation ability, the difference of vertical stiffness in the bottom frame-shear wall structure is bigger, so the structural seismic performance is poor. A six layer bottom frame-shear wall structure seismic strengthening project is established in order to contrastive analyze two kinds of reinforcement scheme, which are additional RC shear wall and additional buckling constraints. Calculation and analysis results show that through setting buckling constraint support in the bottom layer of reinforced concrete frame and selecting rational mechanical parameters, can increase lateral stiffness, reduce the lateral deformation and realize the effect of multichannel fortification. At the same time, the advantage of easy to implement is belong to bottom frame-shear wall structure.

Abstract: The masonry building takes a majority of town housings in these areas. Unlike the experimental study, the Finite Element Analysis is an important part for better comprehension of the finite element method and can reduce the investment and manpower. The aim of this paper is to simulate the structural response from the variety of masonry buildings under earthquake excitations by using finite element software called ABAQUS. There are four models of the masonry building with different storey, which include the one without constructional column and ring beam, with constructional column only, with ring beam only and with constructional column and ring beam simultaneously. In the process of modeling, we adopt the integrated model and regard walls, constructional columns, slabs and steels as homogenous continuums. Furthermore, we adopt concrete damaged plasticity material model to simulate the material of building and input El Centro earthquake wave N-S component. The result of analysis shows that setting ring beams or constructional columns can significantly improve the integrity of the building and reduce the mises stress on foundation. The result of analysis has a significant guidance on masonry building construction in seismic region.

Abstract: The Church of Gesù and the tower of the Cathedral were stricken and damaged by Emilia-Romagna earthquake sequence of May 2012. This paper presents the procedure for the structural identification of the most widespread types of religious monuments. The dynamic behavior was analyzed using the ambient vibrations test to measure the dynamical properties (mode of vibration, frequencies, displacements and damping ratios) of the constructions using a modal identification of output-only systems. The operational modal analysis OMA has been carried out to identify the modal characteristics through poly-reference Least Square Complex Frequency-domain (pLSFC) estimator. The global structural health monitoring was carried out to define the real dynamic behavior of the damaged constructions that are subjected to different mechanism. These researches are useful for the structural rehabilitation and to define the possible changes in the structural behavior.

Abstract: The main purpose of optimum installation of the viscoelastic damper is to make the structure has a better seismic capacity.So we need find a reasonable objective function and a method to solve this function.This paper put forward a kind of optimization method based on the performance objective,explore suitability and feasibility of this method on the steel frame structure,and analyse the results compare with other optimization methods.The analytical method and the results has certain guiding significance for optimization of the viscoelastic damper in practical engineering.