Advanced Materials Research Vols. 255-260

Abstract: The randomness and uncertainty of seismic demand and structural capacity are considered in demand-capacity factor method (DCFM) which could give confidence level of different performance objectives. Evaluation steps of investigating seismic performance of steel reinforced concrete structures with DCFM are put forward, and factors in calculation formula are modified based on stress characteristics of SRC structures. A regular steel reinforced concrete frame structure is analyzed and the reliability level satisfying four seismic fortification targets are calculated. The evaluation results of static and dynamic nonlinear analysis are compared which indicates that the SRC frame has better seismic performance and incremental dynamic analysis could reflect more dynamic characteristics of structures than pushover method.

Abstract: For more reasonable and convenient evaluating structure seismic performance,static elasto-plastic analysis of reinforced concrete frame is presented by pushover with different lateral load distributing modes including uniform distribution, inverted triangle distribution and self-adaption distribution adopted, custom plastic hinge, bending moment-curvity relation and bending moment-axial force correlation of each member section are acquired by Response2000, and time history analysis is used to reinforced concrete frame. It is revealed that the presented method is easy and feasiable, and can generatee stable result.

Abstract: Based on the experimental results of 5 high-performance concrete shear walls, the failure mode, failure mechanism and deformation capacity of shear walls are studied. The new reinforcement method of several bar rings like a chain along boundary element in plastic hinge zone is verified to improve the deformation capacity of shear walls effectively, it indicates that the rotation of plastic hinge zone is related to the damage level of shear walls well. According to the damage level, the storey drift ratio and the rotation of plastic hinge zone are both used as the performance controlling indicators of shear wall structures.

Abstract: The paper explores the failure mode, failure mechanism and deformation capacity of medium-high and low-rise shear walls. The experimental results from load-tests of 5 high-performance concrete shear walls with 1.5 and 1.0 shear span ratio indicate that the shear walls deformation capacity benefits from several bar rings like a chain along boundary element in plastic hinge zone, showing that shear wall deformation capacity design is reliable to a certain extent, in that the plastic hinge zone often influences the damage level of shear walls. With the damage at different stages, the paper divides the performance of shear wall structure into three kinds: serviceability, life-safety and collapse-prevention. Accordingly, it is proposed that the performance controlling indicators for shear wall structures is composed of storey drift ratio and the rotation of plastic hinge zone, and also provides consult values for each performance level.

Abstract: The tensile properties of high performance ductile engineered cementitious composites are tested through 60 specimens divided into 5 groups according to adding 5 various PVA fibres, the tensile strength, tensile elasticity modulus and the tensile pseudostrain-hardening stress-strain curves are obtained, the corresponding matrices are also tested for tension, the tensile strength relationships between different PVA fibres, and between tensile elasticity modulus and tensile strength are proposed according to the test results. In addition, multicracking can be see, and the ultimate tensile strain of partial high performance ductile engineered cementitious composites with filling different PVA fibres can reach to 3% which is 1000 times of the plain concrete. The influences of matrix and the different PVA fibres on ultimate tensile strain, peak stress and peak strain are analyzed by experimental data. At last, the tensile pseudostrain-hardening stress-strain curves are discussed, the experimental conclusions can provide a lot of experimental and theoretical bases for making the composites hold the high ductility consumption ability.

Abstract: One LNR-D1100 isolator at the stage of large horizontal deformation was analysed by FEM program in this paper, which was applied by press-shear load. The maximum S.Mises stress about inner steels of isolator have been researched. The maximum S.Mises stress will occur in the core upload area, with horizontal shear strain increasing. The core upload area will be diminution with horizontal shear deformation increasing, but the maximum S. Mises stress will be larger and larger. When large horizontal deformation of isolator occurs, there is some out-plane deformation at parts of inner steels near the upmost and downbottom of isolator. Vertical pressure will lend inner steels themself to yield when horizontal shear strain of isolator being loaded.When there is 0 MPa vertical pressure on the isolator, no vertical displacement between the top and the bottom of isolator may be helpful for the maximum S.Mises stress value of inner steels of isolator to decrease.

Abstract: Terminal No. A of Kunming International Airport (TA) is a complex steel-concrete hybrid structure. The airport is located in Kunming, China; the seismic fortification intensity is 8 degree. After multi-analysis, base-isolation technique is applied to the structure, and the terminal will be the biggest base-isolated monomer building in the world after its accomplishment. By using ANSYS, the structural FEM model, which is mainly composed of linear beams elements, linear shells elements and nonlinear isolator elements, was established. Demonstration of isolation schemes and influence of isolator’s layout to the isolation efficiency were firstly introduced. And the selection processes of earthquake waves were introduced. Finally, the elastic time history analysis was carried out to study the seismic performance and isolation efficiency of the structure under the frequently and rarely occurred earthquakes. The results showed that not only the expected shock-absorption goal of ‘reduce 1 degree’under frequently occurred earthquakes is achieved, but also the maximal shear displacement of isolation layer under rarely occurred earthquakes can meet the Chinese code requirements. It is concluded that the design of isolation layer is appropriate; the isolation efficiency of the structure after applying base-isolation technique can meet the challenge.

Abstract: In view of the problem that seismic damage evaluation for reinforced concrete structure are difficult to quantify, a new model for seismic damage evaluation was established by five-element connection number based on set pair analysis in the paper, which took internal damage index, maximum inter-storey drift, number of inelastic cycles and energy-concentrated quotient as evaluation factors. All indexes can be summarized into five-element connection number. Four different types of structure are analyzed on the model with more satisfactory results. Compared with the matter-element analysis evaluation method, this model is perfect, the evaluating result is more reasonable and its resolving power is higher. By this practical example, the model proved to be effective in seismic damage evaluation on reinforced concrete structure.

Abstract: Taking the breakage of the conduit joints caused by seismic wave propagation as main failure mode, seismic performance analysis of the pipeline was performed with wave theory method by considering pipe’s axial deformation. Influencing factors of pipe’s deformation such as seismic wave’s incident angle, shear wave velocity, pipeline’s diameter and wall thickness were deeply discussed. Two different methods for calculating axial deformation transfer coefficient were presented to check pipeline’s seismic deformation.

Abstract: Infilled wall is usually used to separate the housing space and it has greatly affected the structural dynamic characteristics. Considering the infilled wall and the frame structure working together, the structure's response under the earthquake is simulated. In this paper, taking the stiffness, strength degradation and pinching effect of structural elements together into account, the authors adopt Reinhorn-Valle damage model to conduct earthquake damage analysis. The result shows that the infilled wall can mitigate earthquake’s damage of main structural component effectively.