Advanced Materials Research Vols. 594-597

Abstract: Wind-gravity coupling effect(WGCE) is an evident phenomenon of extra high buildings. Cantilever model of tall building structure which includes bending and shear distortion is established in the paper. The equations of wind load and gravity coupling have been concluded and are dispersed into difference form. Amplitude frequency characteristic of the structure and vibration acted by simulated wind load are studied though calculation by Wilson-θ method. The result shows that gravity second order effect of extra-high buildings will be enhanced when ratio of gravity rigidity or ratio of bending and shearing rigidity increase.

Abstract: Based on the existing research results, this paper has primarily researched on numerical simulation analysis of a wall-beam joint in complex stress situation in a shear wall structure, in terms of structural deformation, crack of concrete, stress-strain condition of reinforced concrete, bond-slip state of concrete of the joint. The mature finite element analysis software ANSYS is selected as a platform and the parametric design language APDL is used as the foundation. Analyze the deformation of the joint; the cracks and the development status; the strain and stress of the joint and the bond-slip condition between steel bars and concrete. Some problems existing in the results at such joint calculated by commonly-used structure design software PKPM were found to need extra attention and then the paper put forward some feasible solutions.

Abstract: The encased concrete composite beams were modeled and calculated using nonlinear finite element method, considering relative slipping of concrete and steel. on that basis, the load-deformation curve and the relative slip distribution of the models between concrete and steel along the longitudinal beam bottom were analyzed. Then the results were compared with existed test data; in addition, numerical simulations in 4 groups with cotters in different separation distances were performed, the deformation feature and relative slip distribution rule of concrete and steel in different shear connection degree were discussed.

Abstract: Elaborates on the differences between FPB structure in practical uses and classical models, and puts forward a principle of equivalent center of mass of FPB & superstructure by dynamic analysis. It conducts FEA and experimental validation based on the post yield stiffness and vertical displacement calculated in accordance with the principle. The conclusion states that calculating the post yield stiffness and vertical displacement of the bearing by the principle is more accurate than before.

Abstract: Experiment on bearing capacity of 24 Q460 high strength angle steel for compression members attached by one leg shows: the ultimate bearing capacity of the experiment value are higher than the calculated of the “Design of Latticed Steel Transmission Structures” (ASCE10-1997), on the same section in different slenderness ratio of components, the larger slenderness ratio, the higher the ratio; while on the same slenderness ratio in different sections, the greater width-thickness radio, the greater the ratio. Based on this problem, analyzing the current standard, a set of formulas based on high-strength angle struts connected by single Limb was brought, which can used for the design of the Q460 high-strength angle.

Abstract: Space beam-string-structure with outer truss torus is a new type of space structure. The new structural system is to reduce the space occupied by roof structure and could be laid by the rigid roofing material conveniently. Based on the local analysis method and the whole system balance, a simplified calculation method for initial prestress of ribbed grid space beam string structure were proposed when the cable curve equation was determined. An example was investigated and the results confirmed the feasibility of the proposed method.

Abstract: For the pre-stressed concrete structure under marine environment，the stochastic characters of structure and environment such as concrete cover depth, initial chloride ions concentration, chloride diffusion coefficient in concrete, critical chloride ions concentration and structural surface chloride ions concentration affect the structural durability in designed service life greatly. Based on the diffusion mechanism of chloride ions, considering the durability failure character of pre-stressed concrete structure, the limit state function of durability failure is established, the sensitivity of durability influencing parameters is analyzed, and the Monte Carlo simulation is carried out based on the stochastic characters of influencing parameters, which will provide method and foundation for the structural durability design, construction and quality control of similar project.

Abstract: In this paper, the fracture toughness of materials, , effects on fatigue crack propagation that can be quantified using the dynamical coefficient mechanics (DCM) model. And we can not only change the material with high value, but also should take other methods into consideration to decrease the fatigue crack growth (FCG) rate when replacing material can’t obviously decrease the FCG rate, which were examined objectively by the test results from literature.

Abstract: Currently, there are several failure modes in the blot structure of coal roadway. Existing reliability analysis method of blot support structure of coal roadway does not consider the relevance existing among these methods, thus reducing reliability of the blot structure. In order to fix this defect, we put forward the group failure mode of coal roadway bolt structure analysis method taking the relevance issue into consideration. At the same time, we analyze the probability characteristic of blot structure parameters based on the maximum entropy principle; through the normal distribution curve express the coal - rock characterization of cohesion and the friction angle. The Monte Carlo simulation method calculates reliability of the model with the matlab. The results show that the maximum entropy can effectively reflect the probability characteristic of variables in coal roadway bolt structure. Furthermore, Group failure modes allow for the relevance among existing failure modes in the same group, thus in the general, providing more scientific and accurate responses evaluating the overall reliability of the system. Under the group failure modes, the results of reliability are larger than those under traditional reliability analysis method with same conditions.

Abstract: Chloride induced corrosion of reinforcing steel is one of major causes of deterioration of tunnel concrete lining under chloride attack. In this paper, a finite element model for chloride ions transport in tunnel concrete lining was proposed based on the Fick’s second law of diffusion. The governing partial differential equation was solved numerically in space as a boundary-value problem and in time as an initial-value problem by means of the finite element formulations. The maximum allowable value of chloride diffusion coefficient of tunnel concrete lining with service life of 100a was achieved and some constructive suggestions for durability design of tunnel concrete lining under chloride attack were also proposed.