Applied Mechanics and Materials Vols. 405-408

Abstract: The finite element model of space rigid frame with no damage and damage were established by ANSYS and the physical model experiment was carried out. The damage identification methods include that variety rate of three-dimensional vibration mode, curvature mode, strain energy of element mode and axial mode shape difference. Consider identify result and measurement cost that the axial mode shape difference is a good label amount for three-dimension damage identification by vibration method and the single damage and combination damage could identified, which it was proved by the experiment result.

Abstract: Seismic fortification intensity has been adjusted in some areas which were affected in The Wenchuan-earthquake. It was seismic strengthening for most of the buildings especially the public buildings after the adjustment. In order to ensure the seismic performance of the structure after reinforcement ,the analysis method based on performance is gradually applied in the large and complex engineering structure analysis .The paper uses a large span Sports Training Center under construction as background. According to the situation that the fortification intensity by 6 degrees improved to 7 degrees ,the paper uses Push-over method to analysis elastic-plastic of the finite element models ,which including the mild steel damper before and after reinforcement ,under the action of the rare earthquake of 7 degrees. The paper is studying the internal force,deformation and destruction of the structure in the action of the rare earthquake,comparing the dynamic characteristics and seismic performance of the models, and researching distribution of weak links and plastic hinge of the models under the large earthquake. The results show that the models can meet collapse resistant checks less than 7 degrees of the rare earthquake before and after reinforcement. The second floor is relatively weak of the original structure,and can emerge local damage easily. But the structures stiffness is more uniformly after reinforcement, and has large resistance of the collapsed ability.

Abstract: The formulas of effective slenderness ratio of three-leg laced lattice column are given in the Design Specification of Steel Structure (GB50017-2003). Because the expressions of them are related with the sectional area of the column and the lacing bar, and the angle between the lateral lacing bar and theaxis etc, its used complicated. This article applied knowledge of structural mechanics to analyze the calculation process and result of three-leg laced lattice column and deduce more simple formulas. It is proved through practical examples that both simplification formulas and the Design Specification (GB50017-2003) formulas had a similar result, which provided reference to engineers.

Abstract: This paper has conducted the study on calculation of temperature stress for general constrained flexural members under temperature variation in view of the method of structural mechanics, and analyzed the temperature stress of an industrial workshop of large-span steel structure under frequent temperature conditions combined with the climate characteristics of Qingdao city, come to the conclusion that temperature stress should be considered. This conclusion provided a certain reference for the same type industrial building of large-span steel structure.

Abstract: Built-up steel H-shaped beam with variable cross-section design can save steel and realize the economy requirements of structure.The existing design method of variable width of flange of steel beam is only applicable to beam under uniformly distributed load.This paper presents optimization design procedures of the Variable cross-section.The related formulas used to optimization design of section for bisymmetric built-up steel H-shaped beams under concentrated load were derived,and the position of varying cross section of beams under concentrated load was calculated ,it is convenient to be used in engineering design,and provides theoretical foundation for variable cross-section design .

Abstract: Abstract：In order to study Force Performance of new column, the paper describes and presents the results of nine stub-column tests performed on partially encased composite columns made with welded H-section steel. The test studies effect of column about ultimate strength in s steel ratio, wide-thickness ratio of wing, Space of Horizontal bar. Through anglicizing, ultimate strength of short column under axial compression in different steel ratio; influenced factors of ultimate strength of short column and directly effected column about ultimate strength.

Abstract: Abstract: Steel reinforced concrete structure (SRC) is commonly used in high building, but the research on properties of steel reinforced high strength concrete structure (HSRC) composed of high strength concrete and steel reinforced concrete is rarely carried out. In this paper, a series of problems in HSRC structure application is studied, including the steel radio, the stirrup ratio. The conclusions can be served for design specification of steel reinforced high strength concrete column

Abstract: The bending moment changes of slab column nodes in the structure system are analyzed by applying horizontal load to concrete filled steel tubular column and girderless floor, and the experimental values and the theoretical calculation values are compared and analyzed.According to the consequence of comparison and analysis, the ratio of the test value and the theoretical value of the bending moment at the bottom of the plate of concrete filled steel tubular column ranges from 8% to 17%,and the average of the ratio is 13%, and the deformability of the node is better than the ordinary slab column node of concrete filled steel tubular column.

Abstract: In this paper, the effect of different enwrapping methods on the mechanical behaviour of short timber columns were presented and analysed.Five timber columns reinforced by CFRP and AFRP with two enwrapping forms (hoop and spiral) were tested under the axial compressive.The failure mechanism of specimens, the load-displacement relationship and the load-strain relationship were analyzed. Test results showed that the reinforcement with FRP can obviously improve the compressive bearing capacity of the columns and the highest improve ratio is 57.5%. The compressive stress of specimens reinfoced with hooped FRP sheets is much higher than the ones with spiral method. And the lateral deformations of reinforced specimen is greatly constrained by FRP. In addition, the knags of the wood will affect the mechanical behavior of columns on a large extent.

Abstract: During the research of local stress distribution of polyline pretensioned beams by 3-D nonlinear finite element method, a problem of curve prestressed reinforcement simulation is discovered. If the line of prestressed reinforcement is curve, the calculated result of local stress distribution is greatly affected by element size, because of the tectonic stress concentration by the coupling between the linear element and body element. Then, the validity and applicability of the model couldn't be judged. To eliminate the harmful effect, the curve prestressed reinforcement is determined to simulate by body element. The result shows that it will solve the problem thoroughly, and the calculated result is truthful and reliable. This research presents a new thought and method about the local stress analysis of the prestressed concrete structure.