Applied Mechanics and Materials Vols. 438-439

Abstract: Aiming at the defects and potential safety hazard in design of wind turbine generator foundation, taking the wind power project in Huitengxile as an example and based on ANSYS platform, 3-D numerical model is established by introducing the nonlinear contact between the stub of tower structure and the foundation concrete, and the contact between the concrete foundation and subgrade, the effect of step height and load on the stress status of spreading foundation for large wind turbine are studied. The research results provide reference for optimization and design of wind turbine generator foundation.

Abstract: The calculation method of the minimum aperture of transverse joints with spherical surface key groove was introduced in this study. Based on the computation theory of allowable height difference between adjacent monoliths proposed by Bofang Zhu, the analytical model of allowable height difference of Xiluodu arch dam was established with consideration of the effect of main factors on the transverse joints deformation, including the temperature, autogenous volume deformation, self-weight and foundation. After the horizontal and vertical deformations of transverse joints was required, according to the form of spherical surface key groove, the aperture of each part of key groove and the minimum aperture were obtained at several height difference between adjacent monoliths. The allowable height difference was determined on the condition of meeting the grouting requirements of transverse joints. The result shows that the allowable height difference for Xiluodu arch dam should not be more than 30m.

Abstract: According to the application of the concrete face rock-fill dam (CFRD) constructed with soft rock, the physic-mechanical properties of soft rock and the key technologies of utilizing soft rock to construct CFRD are analyzed. On this basis, the feasibility of soft rock as rock-fill of 200m level high CFRD is put forward. The calculation and analysis of specific projects show that the 200m level high CFRD with soft rock is technically established through rational design.

Abstract: A anti debris lash structural competition model of pillar supported house was introduced. Frame structure was adopted in the model and energy conversion beams were built in the hollow floor beams. The upper face of the energy conversion beam was inclined at the support position of the upper column. The energy conversion beam can raise the upper structure when horizontal displacement was produced after collision. Construction details of the model was introduced, structure mechanics analysis and simplified calculation was conducted. By installation of energy conversion beam, the horizontal impact kinetic energy was transformed into the potential energy needed by the rise of upper sub-structure. Experimental result shows the anti impact performance of the structural model is good.

Abstract: The mechanical properties of the whole wall and the wall with openings under vertical loads are analyzed by nonlinearity finite element method (NFEM). The results show that the stress of steel wire has a direct relationship with the load form. The inclined plug wire mainly carries the stress caused by load differences between the two sides of concrete, it makes both sides of concrete work together better. As the diameter of the inclined plug wire increased, the effects on the FQQB mechanical properties become greater, wire mesh stress on both sides decrease, and the vertical displacement of FQQB decrease. Cracks appear above the openings of FQQB which has been cut holes. Steel wire tends to be tension stress concentrated, and there are obvious stress concentration belts on both sides of the opening. However, the size of the opening has little effects on the ultimate bearing capacity of wall panel.

Abstract: In order to improving the performance of Cement-stabilized Macadam (CSM), analyzing the influences of its composition structure on performance, and then putting forward the gradation design principles and strong interlocked framework dense gradation (SISDG), laboratory test was adopted to verify its road performance. Result shows that CSM has the feature of the amount of aggregate above 9.5 mm, below 4.75 mm and 0.075 mm are more, while the amount of aggregate 4.75-9.5 mm is less, and the California Bearing Ratio (CBR) value of mineral aggregate with SISDG is increased by 8~14% comparing with mineral aggregate with the framework dense-graded (DSDG) presented in Design Specifications of Highway Asphalt Pavement (JTG D50-2006) gradation. Compared with CSM with DSDG, 28d unconfined compressive strength (UCS), ultimate UCS and splitting strength of CSM with SISDG are respectively increased by 6~12%, 8~20% and 8~15%.

Abstract: The prestressed concrete beam with pretensioned bent-up tendons combines many advantages of the straight-line pretensioned prestressed beams and the curvilinear posttensioned beams. To improve its application in bridges, long-term deformation should be exactly predicted and controlled. Three prestressed concrete beams with pretensioned bent-up tendons XPB1,XPB2, XPB3 were fabricated, and XPB1 and XPB3 were put in standard curing room, but XPB2 were put in outdoor environment. All the experimental beams were simple supported under long-term loads. Their deformation such as creep strain and long-term deflection in mid-span section were observed about 600 days. By analyzing the influence factor and time-history law of creep coefficient and long-term coefficient, creep coefficient equation of the test beams was fitted and compared with the code model such as ACI209R-92, CEB-FIP MC90 and 86 model proposed by China Academy of Building Research, and the ±10% margin error of this model was pointed out. All these results may offer the initial value of long-term deformation of the prestressed concrete beams with pretensioned bent-up tendons.

Abstract: Through the comparative analysis of theoretical and experiment results, this paper proved that the formulas for solving the strain of composite beams are correct, and the strain is consistent with the plane cross-section assumption. In order to reduce the influence of friction, resin membranes were placed in steel-steel composite beams and aluminum-steel composite beams. The strain measurements were performed on composite beams with and without adding resin, the influence of friction between the composite beams is analyzed by the comparison of strain data,.

Abstract: In order to research torsional performance of prestressed steel-concrete composite box beam with different shear connection, this paper designed three prestressed steel-concrete composite box beams with different degree of shear connection, and studied the stress characteristics of prestressed composite beam under static torsion process load. The torsion behaviors of prestressed composite beam such as the steel strain, concrete flange strain, rebar strain, angle of torsion, deformation and failure patterns are analyzed on the base of the experimental results. It comes to a result that shear connectors have little impact on beams cracking torque, but ultimate torque of composite beams decreases along with the reduction of shear connection degree. When the shear connection degree is 0.5, the ultimate torque is reduced by about 15%.

Abstract: This paper mainly uses ANSYS, the finite element analysis software, to make nonlinear analysis of reinforced concrete beam. The model simulating the test process was established, the calculation results of ANSYS are compared with the experimental results. The comparison shows that ANSYS analysis results are similar to experimental results, which indicates ANSYS analysis software can be used to simulate the mechanical property of reinforced concrete structures.