Advanced Materials Research Vols. 163-167

Abstract: The optimization of mixture proportion is determined by intensive tests based on designed index of the concrete in Three Gorges Dam. It is proved that the crack resistance of the concrete of the Dam is excellent by experiments and investigated results on site. The concrete is designed in a new method which is translated from traditional strength design into durability design. The effective additive and fly ash and moderate heat cement with micro-expansion are applied widely which enhance the capabilities of concrete essentially. So the long-term durability of the concrete in Three Gorges Project is ensured.

Abstract: The numerical simulation by nonfinear finite element method(FEM) was adopted to analyze the behavior and the influences of the fraction of steel fiber by volume fraction and the strength of steel fiber reinforced concrete on the bearing capacity and the ductility of reinforced concrete shearwalls. The results show that with the increase of the fraction of steel fiber by volume fraction, the bearing capacity and ductility coefficient of steel fiber reinforced concrete shearwalls increase gradually. With the increase of the strength of steel fiber reinforced concrete, the bearing capacity and ductility coefficient of steel fiber reinforced concrete shearwalls decrease. It proves the rationality of the unit type, stress-strain relation of material and failure criteria used in the finite element analysis model.

Abstract: Based on fundamental theory and variational principle of thin-walled curved beam and taking into account of coupling effect of bend and shear lag, the paper mainly discusses the variation of curvature radius and the transverse distribution of load in order to analyze effect of shear lag in curved box girder. By means of variational method, the paper derivates the elastic differential equation and boundary conditions and gives numerical results of equations finally, results are obtained by the Galerkin method. It shows that the curvature radius and the transverse distribution of load in the shear lag of curved box girder is very important by comparing the calculating results.

Abstract: The modeling methodology is investigated for steel reinforced high performance concrete (SRHPC) in this paper. According to the mechanical characteristics of the SRHPC members, the structural section can be divided into different zones, and the element suitable for each zone is determined. Some discussion is made for how to control finite element gridding as well as applied load. Hysteretic loops of the computation results and test results agree well with each other, indicating the accuracy and applicability of the methodology. This research may be helpful for the nonlinear finite analysis of the SRHPC frame structure.

Abstract: This paper presents a method for designing and predicting the flexural behavior and capacity of concrete beams with mixed CFRP-GFRP bars. The design of the section with CFRP-GFRP bars is expected to obtain better performance in serviceability and deformability comparing with the section with only CFRP bars or GFRP bars by realizing successive rupture of CFRP and GFRP bars in the section. The corresponding equations are proposed to calculate the flexural capacity, strain and stress of the section. The calculating values of flexural capacity are compared to existing test results and it is found that the calculating values are in good agreement with the experimental results. Further analysis on a calculating example shows that the section with CFRP-GFRP bars designed appropriately presents excellent performance.

Abstract: The cyclic tests of three one-storey spatial RC frame-shear wall structures with slabs were conducted to investigate the failure modes and the base shear-floor displacement hysteretic responses of the model structures. Then three dimensional numerical simulations were performed using the finite element program ABAQUS/Standard and ABAQUS/Explicit. The test results are detailed in this paper and compared to those of the numerical simulations. It is shown that: (a) plastic hinges initiated at the bottom of the shear wall and followed by forming near the upper ends of columns, resulting in wall-column hinges side-sway failure mechanism; (b) to a certain extent, the horizontal force bearing capacity of the structure increases with the increasing of the vertical load; (c) it is verified that the pushover results of both ABAQUS/Standard and ABAQUS/Explicit solutions agree well with the test results in the case that the parameters are reasonably chosen.

Abstract: Moment-deformation curves of square steel tube filled with steel reinforced concrete subjected to bending load were simulated by the ABAQUS software. Calculated and experimental curves agreed well with each other. Through studying further the calculated member, the behavior of materials subjected to moment is given. Finally, flexural capacity formula of square steel tube filled with cross steel reinforced concrete is proposed.

Abstract: Square steel tube filled with steel reinforced concrete subjected to shear force was simulated by finite element method. Limit value of broken on pure shear, bending-shear and bending were given. Influence of stirrup ratio, steel reinforced ratio, strength of concrete under shear force was also analyzed. Finally, formula for pure shear capacity of square steel tube filled with steel reinforced concrete was proposed by research the calculated results. Calculated results showed that it agreed well with that of corresponding document.

Abstract: By using finite element method, analysis the static response of internal force and displacement of gravity dam under water and no-load factors. The change of the stiffness ratio and the difference of dam and foundation stiffness at the dam heel and toe are considered. The stress in the key parts of the dam and the maximal displacement on the dam top are obtained. It is found that the change of foundation stiffness affects the stress of the dam, and the displacement decreases with the increasing of the foundation stiffness. Some computational results and conclusions are the theoretical basis for the optimization design of the gravity dam.

Abstract: Based on the experiments of 10 model specimens of fiber reinforced high strength concrete three-pile caps with the dimension of 831mm×831mm×831mm, the mechanical behavior and the important factors on the cracking load and ultimate bearing capacity of fiber reinforced high strength concrete three-pile caps were researched. The study indicates that with increasing of concrete strength, the volume fraction of steel fiber, the effective thickness and reinforcement ratio of pile cap, the bearing capacity of three-pile caps improves largely. At the same time the type of steel fiber and steel ratio have remarkable effects on the bearing capacity. The results are valuable for establishing bearing capacity calculation formulas of fiber reinforced high strength concrete three-pile caps and improving “the Technical Specification for fiber Reinforced Concrete Structure.”