Applied Mechanics and Materials Vols. 638-640

Abstract: On the basis of the joint model experiment, the non-linear performance of joints is analysed by using finite element program. The concrete stress distribution, stirrups stress and dangerous area of joints with spread-ended beams are discussed. Finite element analysis shows that effective prestressing tendons through the joint core region play a beneficial role in concrete and can improve the compressive strengths of concrete, and help to improve the shear strength of joints. Finally, according to experiments and theoretical analysis, the beginning of the haunched region is the dangerous area of joint. In order to avoid concrete tension failure when exerting prestress, the beginning of the haunched region must have enough transverse U-shaped bars to resist the prestressing tension.

Abstract: the framework structure beam-column node stress is complex, the traditional design, the strength grade of concrete frame column than beam slab concrete strength grade is high, the construction to bring huge inconvenience. After some experiments and experience, the design of beam-column joints of concrete strength grade should improve, convenient construction, improve the quality of engineering.

Abstract: The serviceability limit state of structures is subject to increasing attention. Flooring-systems may encounter vertical vibrations that may be perceived as annoying by stationary persons sitting or standing on the structure. This paper looks into human induced floor vibration of a 33-storey residential building by using theoretical analysis and in-situ inspection. The results show that though the vertical eigenfrequency of the floor satisfies the demand of vibration comfort stated in the Technical Specification for Concrete Structures of Tall Buildings (JGJ3-2010), the maximum value of vertical vibration of the floor system is excessively large, which is caused by the stiffness shortage of the floor due to the decreased floor thickness.

Abstract: In order to exert the force performance of steel tubular columns filled with steel-reinforced concrete, the focus of the paper is about the influence of load condition on flexural mechanical properties and the shear mechanical properties of the composite columns. The two types of loading conditions are: 1.Steel pipe, steel placed in the steel tube and concrete subject to compressive load simultaneously; 2.Compressive load acts on steel and concrete. The results show that the calculated results based on ADINA and the experimental ones are in agreement well. The calculated results also show that the load condition has no influence on flexural mechanical properties, but has a great influence on shear mechanical properties of the composite columns.

Abstract: By using the finite element software ADINA, the focus of the paper is about the influence of load conditions on the axial compression performance of steel tubular columns filled with steel-reinforced concrete (STSRC) with the base that the calculated results are confirmed by the experimental data. Three types of loading conditions are these that: 1. Steel pipe, steel placed in the steel tube and concrete bear the compressive load; 2. Compressive load acts on the steel and concrete and there is a good bonding between the steel and concrete; 3.The steel and concrete bear the axial load, but the bond-slip between the steel tube and concrete are considered. The results show that the calculated results based on ADINA and the experimental ones are in agreement well, the bearing capacity and the ductility of the short composite columns are not almost influenced by the load condition-one and load condition-two, while the load condition-three has a influence on the axial compression performance of STSRC.

Abstract: A KNN Classification Based MCS (Monte Carlo Simulation Method) is proposed for the reliability analysis which hindered by the implicit nature of the performance function. In the method, Markov chain is adopted to simulate a small amount of training samples, KNN classification is used to generate surrogate model of performance function, MCS is used to estimate the failure probability. An iterative algorithm is presented to improve surrogate precision dynamically in the region contributing to the failure probability significantly. The study results demonstrate that the proposed method has superior performance to the traditional response surface method.

Abstract: Steel-concrete composite structures are widely used in large-span spatial structures, high-rise building, super high-rise building and bridges and so on thanks to its advantages in terms of mechanical and construction properties. And the corresponding design codes on circular, square and polygonal concrete filled steel tube (CFST) have been formed at home and abroad. However, application of round-ended CFST is still very rare in the world and there is no corresponding theoretical research findings and design basis. There is an actual project that a round-ended CFST coupled tower column is applied in Houhu Bridge in Huangpi area, Wuhan city. Real-time stresses of the coupled tower column were monitored throughout construction phase to ensure that the force and linearity of Houhu Bridge can meet its design requirements. In the paper, the real-time stress monitoring data is analyzed so as to find force state and force characteristics of this new structure of round-ended CFST during construction phase. This study provides basic information for further formation of round-ended CFST design theory in future which plays an important role in engineering application of the round-ended CFST.

Abstract: In order to promote the ability of independent research of Movable Scaffold System (MSS for short), this article studied the mechanical characteristic and the structure optimization about the main girder of MSS from a company. The FEM model for the main girder was established by ANSYS to study its static mechanical properties. Considering the cross section is discrete in the real projects, the genetic algorithm (GA) is used based on MATLAB by calling ANSYS, which effectively reduce the structural weight by 8.5% and 9.6%, separately. The results of modal analysis indicate that the natural frequency of the main girder ranges from 4Hz~12Hz, which satisfy the need of crane design. The conclusion of this article and the optimization method of exploration research have certain reference significance for similar products.

Abstract: Tubular structure can be damaged severely by collision accident. To study the failure mechanism of tubular joint under lateral impact force, typical tubular K-joint is selected as basic theoretical analysis model and it is simulated by nonlinear finite element software ABAQUS. On the base of numerical analysis, the development law of deformation and stress is clarified, and the failure mode of tubular K-joint is analyzed in the course of impacting.

Abstract: Based on the APDL parametric design language, the models of the first to the tenth-order for the vibration isolator of the laminated curved plate were analyzed. The natural frequencies and maximum deformation for resonance of all modes were obtained .Then the curves of the influences on the natural frequency which was influenced by the thickness of the curved plate were concluded. The result shows that the thicker curves plate is, the smaller the value of the natural frequency is.