Papers by Author: Shan Suo Zheng

Abstract: With the rapid development and extensive application of SRC (steel reinforced concrete) frame structures, the study on seismic fragility of SRC structure under earthquakes seems rather important. The seismic fragility of the SRC frame structures is studied by the method of Incremental Dynamic Analysis (IDA) in this paper. IDA method is conducted on 9 storey SRC frame structure to obtain the IDA curves of this model. Meanwhile, the seismic fragility of the model is analyzed to get the fragility curve. The result shows that IDA can describe the quantitative relationship between the exceeding probability of different states and damage degree of the target.

Abstract: Based on the flexural experiments of 10 SRHSHPC (steel reinforced high strength high performance concrete) simply supported beam specimens, the destructive process and modes were observed, analyzed its flexural failure modes and mechanisms, and investigated the influencing factor for the flexural behavior of beam, such as concrete strength, steel ratio, flange width ratio (the ratio of steel flange width to beam width) and shear connections. Finally, a formula which was suited for the flexural capacity of cross section of SRHSHPC beam was established. Research result will provide a theoretical basis for the establishment of related calculation theory and engineering application of SRHSHPC beam.

Abstract: In consideration of stochastik and discreteness of fracture surface, a class of mesoscopic damage mechanics model of concrete based on spring model, are put forward to understand the real damage evolution characteristics of concrete at the level of constitutional law. A kind of spring-slipper model is introduced to reflect the elastic-plastic damage behavior. Uniaxial test was operated, combined with the Computerized Tomography test of concrete, to study the evolution of crack surface from mesoscopic level to macroscopic level. And the rationality of fractal damage constitutive law was verified with their theoretical calculation result and test results. Compared with the existing damage constitutive law and experimental results preliminarily, the feasibility of fractal damage constitutive law is verified.

Abstract: Based on the kind of damage constitutive models, such as spring friction block model and spring model, which are proposed for ordinary concrete by domestic and foreign scholars, and taking the differences which are caused by different failure mechanisms in mechanical properties of HSHPC and ordinary concrete into consideration, this paper presents the spring-friction block model which is suitable for revealing the stochastic damage constitutive relation of HSHPC material subjected to uniaxial tension stress. By introducing the failure strain stochastic field of concrete material subjected to uniaxial compressive stress, and according to the principle of energy conservation during the process of damage failure, the stochastic damage constitutive equation of HSHPC material subjected to uniaxial tension stress is derived. The theoretical results agree well with the experimental conclusions, and it shown that the proposed stochastic damage constitutive relation can objectively reflect the failure mechanism of HSHPC material. The research achievements will provide a basic research method for establishing the dynamic damage constitutive relation of HSHPC material.

Abstract: Considering of the condition that the steel reinforced concrete beam is mainly used to bear the vertical load and preserve the robustness of integrated structure, this paper takes the flexural rigidity of beam subjected to short-term load effect as the damage characterization of SRC beam. According to the related theoretical analysis and experimental research, the damage sensitivity of various design parameters which contain the sectional height, the strength of concrete and steel ratio are analyzed, and the influence laws of main design parameters impacted on damage evolution of SRC beam are revealed. The research shows that sectional height is proved to be the most sensitive factor in the damage of SRC beam and the steel ratio takes the second place, and then the strength of concrete is the most insensitive to the damage of SRC beam. The research achievements will provide theory and date support for establishing the storey damage model of SRC frame structure under seismic excitation.

Abstract: This paper studies the High strength and high performance concrete that is suitable for the steel reinforced concrete. In the basis of meeting the durability, strength, workability and volume stability, the mix proportioning of high strength and high performance concrete is optimized in the aspect of engineering cost . By experiments, minimum range of mix proportioning is defined which can meet the requirement of the every performance of high strength and high performance concrete, constraints are given, then, mathematical model of the optimization design for mix proportioning of high strength and high performance concrete is determined. Linear optimization problem is solved by MATLAB programming. Optimization example shows that optimization approach is feasible and effective in the paper.

Abstract: In order to study the displacement ductility coefficient of steel reinforced high-strength concrete column, 23 groups of components with various design parameters were tested and related factors that affect the displacement ductility coefficient of SRHSC column were presented in this paper. The proposed formula for calculating the displacement ductility coefficient of SRHSC column can be obtained from the multivariate nonlinear regression of test results by using SPSS. The calculation results agree well with the test conclusions, and it shown that the proposed formulas own high accurateness and can be objectively reflect the mechanical behavior of SRHSC column root. The research achievements will provide a theoretical support for the design of SRHSC column.

Abstract: Genetic algorithms (GA) are very effective at finding optimal solutions to a variety of problems. This innovative technique performs especially well when solving complicated real-world problems. Therefore, this paper aims to use the fuzzy analytical hierarchy process (AHP) GA approach to optimize SRC beam. In the process of optimization, the matlab toolbox with GA is used. To increase the performance of the genetic-based approach for optimization problems, the design constraints related to member stress, bending moment etc are described by using fuzzy set theory. Finally, a example for beam optimization is presented. The example shows that the approach is flexible enough to deal with optimization of SRC beam.

Abstract: To simulate the hysteretic behavior and propose the analytical model of steel reinforced concrete (SRC) columns under low cyclic loads, different fiber models which can reflect the mechanical behavior of materials are used in this paper. The unconfined concrete, partially confined concrete, highly confined concrete, structure steel and longitudinal reinforcement bars of the complex cross section can be established by OpenSees program which can define the different fibers for kinds of materials with their own stress-strain relations, respectively. Based on fiber models, the analytical model for simulating the hysteretic behavior of SRC columns is proposed. By comparing with the conventional simulation results, the results which are obtained from the proposed analytical model in this paper agree with the experimental results better.

Abstract: According to the thought of engineering optimization and the theory of composite structure design, the minimum of the project cost and the maximum of the diagonal shear capacity are taken as the optimization objectives whose importance can be adjusted by weighting factors and the linear weighted method is used to establish evaluation function which changes multi-objective into single-objective in optimization. Taking the various constraints into consideration and choosing the sensitive design variables, the mathematical model of the multi-objective optimization design for steel reinforced high-strength concrete beams is provided. Based on the optimization thought of the Complex Method, the nonlinear optimization problems are solved by MATLAB program.