Applied Mechanics and Materials Vols. 94-96

Abstract: An anemometer tower is essential for the construction of an offshore wind farm. A anemometer tower is preliminarily designed in the Bohai Bay in the north coast of China. Considering the extreme wind and wave or extreme wind and ice, at different directions, the structure of the tower is simulated by using finite element software. And the stresses and strains of the structure are calculated at the different loadcases. And then, the structure of tower can be designed using the numerical data. And finally, the dynamic characteristics of modal shape and frequencies are also discussed.

Abstract: In this paper both a hollow floor and the corresponding solid floor are analysed by using finite element software and the results are compared. The comparison is made through a detailed finite element study between a column-supported cast-in-situ hollow floor filled by tube with its solid counter-part. The orientation of the tube fillers causes the stiffness of the hollow slab to be orthotropic, potentially changing the distribution of load carrying between the two orthogonal directions. The inclusion of the hollows also potentially increases the flexibility of the slab. Recommendations for design of column-supported cast-in-situ concrete floors compared with the solid floor are then made with respect to distribution of design moments and calculation of deflections. Thus the reference was given to the designer.

Abstract: Abstract：According to our team experimental study on the joints for the Multibarrel tube-confined concrete column and the reinforced concrete ring beam, The software ANSYS of finite element is used to simulate the behavior of connections in this paper. The simulated hysteretic curves and skeleton curves are compared with the experimental data and good agreement can be observed. Moreover, parametric studied have been carried out to investigate the influences of anchorage length of vertical steel bars for the nodes area, the strength of the concrete for the nodes area, the concrete strength of the frame beam, and the longitudinal reinforcement ratio of the frame beam on the skeleton curves.

Abstract: This study develops a blocked cost model of urban rail transit, which is applied to determine laying mode of urban rail transit. In addition, this model focuses on the laying mode choice of urban rail transit by using quantitative analysis, which is previously discussed by using qualitative analysis. The case of Line No. 1 of Shijiazhuang urban rail transit is given to demonstrate the blocked cost. The results show that the cost of urban rail transit on the ground is 0.372 billion RMB per km and the cost of urban rail transit underground is 1.79 billion RMB per km. The mode on the ground is the best solution due to its low cost. But by analyzing and evaluating generalized cost in which blocked cost has been considered, the mode of urban railway transit underground is the best choice due to 1.79 billion RMB per km compared to 1.91 billion RMB per km on the ground.

Abstract: 14 models of plate-reinforced connections are analyzed by finite element software ANSYS. Failure mode, hysteretic behavior, ductility and energy dissipation capacity are comparatively studied. Results show that plastic hinge formed at the end of the reinforced plate, hysteretic cruves are full and the connections have good ductility. With the increase in length and thickness of the reinforced plate, bearing capacity increases while hysteretic behavior and ductility factor decrease. If the reinforced plate is longer than the length that design requires, brittle failure occurs in the panel zone. The recommended length of the reinforced plate is defined as 0.5-0.8 times of beam depth, the thickness of flange-plate is 1.2-1.4 times of flange thickness and the thickness of cover-plate is 0.7-1.2 times of flange thickness.

Abstract: Based on cyclic loading experiment of six beams in the two groups, the relationship among the stirrup stress, initial diagonal crack width and shear capacity of RC beams was studied. Experimental result shows that the decline of the shear strength of the RC beams due to cyclic loading can be characterized by the width of diagonal crack, according to the experimental phenomena, a formula for shear capacity after cyclic loading is derived for engineering use. To study the mechanism of the capacity decline, considering the effect of the width of diagonal crack to the shear transfer coefficient, numerical analysis by FEM method was done, the result is compared to the experimental result.

Abstract: The physical explanations both of positive or negative shear lag are given in this paper. The shear lag effects occur attributing to the abrupt change of shear stress at junction upper the web. The abrupt change of shear stress or called shear stress jump changes the stress magnitude of the flange bending stress, which attenuates gradually at increasing distances from the web. Meanwhile, the abrupt change of shear stress from zero to the flange shear stress also influences the bending stress state at the centerline of the slab. The method to determine the shear lag has given, which is based on the Euler-Bernoulli elementary theory of bending. Considering the transversal distribution of the shear stress at the junction upper the web, the real flange bending stress could be calculated all on the section.

Abstract: Energy dissipation equation is obtained from the virtual work principle. By assuming different initiative sliding directions, methods of upper bound solution and classical solution for rock wedge stability are deduced. The computational formulas of safety factor indicate that the safety factor of wedge is depended on the areas of sliding surfaces and the volume of the wedge rather than the shape of the slope when the attitude and strength of discontinuities is given. Therefore the current wedge method can be improved to overcome the weakness that the current method is inapplicable when the slope shape is greatly rugged and the wedge is surrounded by more than three discontinuities. As an example, the improved method is applied in the left bank slope of Baihetan hydropower station. The calculation results obtained by the improved methods is more reasonable and credible.

Abstract: Low strain ingtegrity testing of pile is based on the one-dimensional wave theory.However, the pulse wave produced by hammer is actually 3-dimensional wave , whose propogation could be affected by the pile sides with different geological conditions. The effect is more obvious when the geological conditions of the pile sides become more complex. This test established three-dimensional finite element model which has fixed pile bottom and different geological conditions by applying ANSYS/LS-DYNA dynamic analysis method. The test simulated nine different boundary conditions of the pile sides. The results were divided into four groups to compare. And the velocity-time curve of the particle in different conditions was obtained. Through analyzing the simulation data, the conclusion that the stress wave is affected by the boundary conditions of the pile sides could be made.

Abstract: It has studied the characteristics of the work force of the geogrid-reinforced and pile-supported foundation through eight loading model tests, and analyzed the effects that varied pile spacing, reinforced floors, the paving position of the reinforcement have had on the stress concentration ratio of the pile to the soil of the geogrid-reinforced and pile-supported foundation, the pile axial force, the tension of geogrid.