Applied Mechanics and Materials Vols. 351-352

Abstract: Buckling-restrained braces (BRBs) have been widely used in earthquake resistance structure systems, which are designed to yield in both tension and compression. Among most mortar filling BRBs, the bearing capacity in compression is higher than in tension particularly at large displacement. This leads the joints to suffer extra force and thus unfavorable for structures. This paper presents a set of experimental results of BRBs with different unbonding materials and specific nonyielding segments. Four models with different unbonding materials are tested in axial compressive with stationarily increased displacement amplitudes. These models are all featured with reinforced nonyielding segments to prevent lateral buckling. Both experimental and numerical results indicate that epoxy resin is the best unbonding material that can avoid transferring the axial force to the restrained part and the new reinforcement in nonyielding segments can effectively prevent lateral buckling.

Abstract: After hundreds years damage, the disease of stone structure member is very severity, and so structure reinforcement has great significance. In this paper, the bending capacity of stone member reinforced with CFRP is studied through the test combined with the protective project of Huangsong Stele. The tests totally have six stone beams to study the mechanics performance and damage model of original and reinforced stone beam. The bending capacity theory of reinforced beam is discussed. The study results revealed that the bending performance of stone beam reinforced with CFRP can ameliorate greatly, and the destroy model change from brittle failure of normal section to ductile failure of oblique section, and the bend-resisting capacity of stone beam reinforced with CFRP can be enhanced greatly. But the enhanced range isnt direct proportion with the dosage of CFRP. The calculate formula of bending capacity got from theory deduce joint the test result, so it can be used to guide the design of fact project. So, the reinforcement of stone bending beam with CFRP have well effect.

Abstract: Many factors need to be considered during the choice of strengthening scheme for arch bridges, and most factors are fuzzy. The reasonable and scientific strengthening scheme is an important precondition to ensure the effectiveness and quality of the strengthening engineering. The elementary objects of the bridges strengthening are effect reliability, economic reasonability, technological feasibility, and convenience of construction, which are used to appraise the strengthening scheme. Based on the basic objective of bridge strengthening, two levels fuzzy comprehensive appraisal index system of strengthening scheme are established, and the best scheme is chosen. Combining the idiographic example of arch bridge reinforcement, the process of fuzzy analytic hierarchy and optimum result is given. The result tests that fuzzy analytic hierarchy method is feasible during the preferred selection on strengthening schemes of arch bridge.

Abstract: Based on micromechanics, an elastic-plastic-brittle damage model of concrete beam reinforced with stick steel is proposed by considering the aggregate gradation curve algorithms and the heterogeneity. In the model, the concrete beam reinforced with stick steel is taken as a five-phase composite material that consists of the mortar matrix, coarse aggregate, bonds between mortar and aggregate, steel plate, and the adhesive layer between steel plate and concrete beam. Through the numerical investigation on shear failure of concrete beam reinforced with stick steel under external force, the results show that the model can clearly simulate microscopic plastic yield, and the initiation and extension of crack. The strength of the steel plate is relatively stronger, so it cant enhance the shear capability of the each side of the beam and the concrete beam bears the larger shear stress, which results that a large number of elements, from the supports to the load points, begin to yield. When the strain of the elements exceeds the yield strength, the elements will produce failure until the failure of the whole specimen. The final failure mode of concrete beam reinforced with stick steel is the shear failure.

Abstract: To protect museum cultural relics, seismic damage causes as well as aseismic strengthening methods of free-standing museum cultural relics were studied in this paper. Museums, cultural relics and their bases were all considered to study causes of damage of free-standing relics. Shortages of typical domestic aseismic methods were discussed, overseas isolation techniques were introduced. Based on 2 typical examples, reasonable strengthening methods for museum cultural relics were further demonstrated. Results show that main damage causes of museum cultural relics under earthquakes relate closely to over strong earthquake intensity, shortage of strengthening measures of relic, destruction of showcase or museum building and so on; museum, showcase and relic are all important factors for aseismic strengthening of the relics. Besides, to effectively protect the relics, traditional strengthening methods have to be improved; development as well as application of new isolation devices is encouraged.

Abstract: Chinese ancient wooden buildings have good aseismic constitutions to survive sorts of natural disasters. However, under earthquakes damages still occur on some of them. To protect Chinese ancient wooden buildings, typical aseismic constitution problems as well as strengthening methods of their members were studied by classification and statistical methods. Based on survey results on large number of Chinese ancient wooden buildings, typical aseismic constitution problems were summed up, causes for the problems were analyzed and the corresponding strengthening methods were proposed. By 2 compared examples, typical strengthening methods were further demonstrated. Results show that typical aseismic constitution problems of Chinese ancient wooden buildings include decay of column root, slack of Tou-Kung, tenon pulled out of mortise, cracks of beam and column and so on; to solve these problems, methods such as replacement, wrap, connection, ensemble and so on are feasible.

Abstract: In this paper, through the study on the non-probabilistic based on the interval analysis of soil structure, solves the key theoretical issues of non-probability measure and methods, It is more suitable for evaluation of the roadbed design problems with less experimental data.

Abstract: Since the application restrictions of JC method for hydraulic structures reliability, and the drawbacks of Monte Carlo method for large and complex hydraulic structures, this paper combines MATLAB with Monte Carlo method to analysis and calculate hydraulic structures reliability. Also, this paper puts forward the grading standards for hydraulic structures reliability. Taking a masonry gravity dam for example, using the Monte Carlo method and MATLAB programming to analysis the dam's sliding and strength failure risk, and then grading the dam. The results show that the application of MATLAB-based Monte Carlo method in hydraulic structures reliability is simple and quick, with good usability and operability.

Abstract: Cracks provide diffusion path for chloride ions transport from the external environment into the concrete, resulting in the durability degradation of concrete structures. In this paper, the boundary condition of cracked concrete and chloride diffusion coefficient in crack were analyzed. The time-dependent chloride diffusion model was established based on the time-dependent chloride diffusion coefficient and the Ficks second law of diffusion. The influence of crack on the concentration distribution of chloride ion in cracked concrete was quantificationally investigated.

Abstract: Considering the resisting force variation with time, JC method was adopted to calculate the reliable indicator of the reinforced concrete bridge with simply supported beams based on the field test data. Combined with the classification of security evaluation, the bridge is evaluated as type 5 and rebuild measure was suggested.