Advanced Materials Research Vols. 243-249

Abstract: This paper investigates the influence of thermal stress on FBG embedded in GFRP bar by the finite element analysis and the calibration test. The temperature sensitivity coefficient of smart FBG-GFRP analyzed by FEM is 17.42 pm/°C, which is about 1.65-fold of bare FBG’s namely 10.53 pm/°C. And the coefficient got by calibration test is 17.6 pm/°C. The result shows that the influence of thermal on FBG is very big, after encapsulated and before used in structure, the temperature sensitivity coefficient of FBG must be calibrated.

Abstract: Concrete quadratic transfer beam is definite completely based on the specifications. It is using ANSYS finite element software to optimize models rationally and calculate the structure with quadratic transfer beam under seismic action. Compared the mechanical characteristics of the two models of quadratic transfer beam, we can know that the wall on quadratic transfer beam played an important role in the mechanical characteristics. When there is no wall on quadratic transfer beam, the conclusions are banned used. It can provide a reference for design of engineering with quadratic transfer beam.

Abstract: Shape formation of post-tensioned and shaped hypar space truss is presented in this paper, the test space truss can be deformed into saddle shape by tensioning positive diagonal bottom layer strand. Nonlinear finite element analysis is applied in shape formation of space truss model. Based on both geometry and material nonlinearity, new FEM refering ‘tube to tube’ contact, is employed. Connector elements are used to simulate the bolt connection of the top joint, and the end of web. The results show that new method is relatively much more accurate than the previous way for the shaped size, and the theoretical values are consistent with experimental ones in stress and internal force distribution trend although the former ones are smaller, for FE model could not consider diagonal lower chord joining the structural system during shape formation.

Abstract: Based on the ANSYS, castellated lightweight steel portal frames are modeled to analysis the stress destruction process and stress distribution rule under horizontal and vertical loads. The comparative analysis with the original solid-webbed portal frame in yield load, ultimate load, the mid-span deflection is pursued. The results show that: there are some differences in failure mode between the castellated lightweight steel portal frame after expansion and the original solid-webbed portal frame. The former bearing capacity and rigidity increase by a large scale than the latter.

Abstract: Based on the unified strength theory, the bearing capacity of the concrete filled square steel tube short columns with inner CFRP circular tube under eccentric compression was analyzed. The restriction effect of the inner CFRP circular tube upon the core concrete, strength reduction factor for eccentricity ratio and the equivalent reduction factor, which considered the ratio of thickness to side effect, were taken into account in the theoretical analysis. The axial bearing capacity formula of the square steel tube short columns filled with inner CFRP circular tube was deduced. By introducing the strength reduction factor for eccentricity ratio, the eccentric bearing capacity formula on the basis of the axial bearing capacity formula was obtained. Parametric studies were carried out to evaluate the effects of intermediate principal stress, different CFRP deployment ratios, eccentricity ratios and the tension-compression ratio on the eccentric bearing capacity of the column. The formula was verified by the comparison of the theoretical results with the experimental data. The results show that inner CFRP circular tube can effectively restrain the core concrete.

Abstract: Shear strength reduction finite element method (SSRFEM) has been a main technique for stability analysis of slope. Although SSRFEM has advantages to deal with complex geometry and nonlinear material, the criteria for failure is still argued. Ideal elastoplastic model and rheological model were both adopted, and the results of computation showed that using the intersection of two straight lines as failure point was more appropriate. The usage and advantage of two different material models was compared.

Abstract: In this research, a kind of composite cement plates are utilized as permanent formworks, and poured concrete together to form composite slabs. Through static test of composite slabs with different bonding modes of interface between formwork and concrete, bearing capacity, deformability and cooperation states of concrete and composite formwork are studied. Through static test of composite slabs with splicing joints formworks at different positions, bond quality near the splicing joints are observed visually, stress nature and deformability variations resulted from different splicing joint positions of formwork are analyzed. And meanwhile, stress and deformability of the ordinary concrete slab without formwork is researched under the same conditions. Through above experiments, acting as a part of the slab, how composite formwork influence bearing capacity and deformability of the combined slab is investigated.

Abstract: Based on the research of Life Ring in Shen Fu, the basic criteria for structural design of the unconventional rigid mega-structure linked with the ground are proposed in this paper. Through the structure comparison and selection, the space steel truss is used as the optimal structure form. After static analysis and time-history analysis by FEM, it is found that the control load case is the combination of dead weight and wind load. Because of its long vibration period, the structure is not sensitive during an earthquake. The key design of the structure is the selection of foundation form, a mixed-foundation made of steel trusses with piles is proposed in this paper. The steel truss is used as a bridge which transmits forces between superstructure and foundation. At last, the pile foundation is classified by the loading mechanism, the analysis and design of key joints in the mixed-foundation is proposed.

Abstract: The research focused on the effects of infill walls on the RC slab-column structural system. In order to accomplish this, the elastic-plastic time-history analysis of RC slab-column structure was performed. Based on the test results of a full-scale three-story RC structure repaired and strength with masonry infill walls, the four optional analysis models were analyzed. The first was the pure RC slab-column structure without infill walls, the second was the RC slab-column structure added with half-height infill walls, which was equivalent to open holes inside infill walls, the third was the RC slab-column structure added with infill walls arranged symmetrically along the plane symmetric axis, and the fourth was the RC slab-column structure added with infill walls arranged around the plane geometry center. Analysis results indicated that addition of infill walls could increase the seismic performance of the structural system, configurations and amounts of infill walls, and the hole positions and sizes inside infill walls had effects on the structural system.

Abstract: The damage of reticulated shell structure will arouse structural mode localization. The quantitative assessment index of mode localization is defined. A scale model experiment for mode localization is carried out on a Kiewit single-layer spherical reticulated shell structure, and the features of mode localization are studied. Four cases about structural stiffness’ change are constructed in the experiment, and three structural modals are obtained at random. The localization of the three modes is analyzed under each case. The results show that slight changes of physical parameters are likely to arouse obvious localization of some modes for reticulated shell structure.