Applied Mechanics and Materials Vols. 578-579

Abstract: Friction Pendulum Systems have been used as base isolation systems for both new construction and retrofit around the world. This paper presented its implementation in an office building located in Shanghai. To evaluate its impact on seismic performance of the retrofitted structure, models are needed to capture the intricate nonlinear behavior of both structural components and isolator elements. Nonlinear time history analysis of the building for the original and retrofitted cases was conducted to assess the efficiency of the isolation system at the high earthquake level. The numerical results indicate that the retrofitted structure experiences significantly less damage and less deformation due to the shake isolation and energy dissipation through the isolators.

Abstract: In recent years, the carbon fiber reinforced plastics (CFRP) has been widely used in field of structural reinforcement. To investigate the effect of different amount of CFRP strengthening pre-stressed concrete hollow-core slabs and the capacity calculation methods, test data of six slabs reinforced with CFRP at different amount were compared to obtain a available calculation formula of flexural capacity. The results showed that the bearing capacity and ductility of these specimens are significantly improved strengthened with CFRP; the proposed method of calculation is safe, simple, practical and relatively high accuracy, the calculation results coincide well with experimental results, and it has a certain reference value for the calculation of the followed studies and practical projects.

Abstract: Carbon fiber material is a strengthened repair material that is new and efficient, and it has so many advantages such as excellent strength, efficiency, construction easily and extensive use. Corrosion-resistant and little section are the most important characteristics. Carbon fiber strengthened technology affix carbon fiber sheet to the surface of a member with epoxy binder of transferring character, thus causing the strengthened member and the improvement force of the member. The strengthened plan, design principle and construction courses are demonstrated by using carbon fiber composite reinforcement technology on little side and moisture condition. Carbon fiber is a kind of material which is extensive uses, endurance and corrosion-resistant according to project illustration, and it is exampled in similarity projects.

Abstract: Concrete structures are exposed to severe environment that may cause rapid decay, shortening their service life and raising maintenance and repair costs. Chloride ions will lead to the depassivation of reinforcing steel bars in concrete which is one of the most serious problems to the durability of concrete. Then, the prescriptive methodology is not a guarantee to obtain the desired service lives of 50 or 100 years. Surface treatment is commonly used to improve the resistance of concrete to chloride erosion. Using the silicone materials to an immersion treatment can effectively block the invasion of harmful substances,the resistance of concrete to chloride penetration with surface protection with silicone materials was evaluated. The results showed silicone can improve the resistance to chloride penetration than the non-protected concretes. As a kind of polymer materials, the aging behaviors of silane is a matter of urgent concern. Hence, the aging behavior of silane coated concrete is evaluated by the test of water absorption after 1000h xenon lamp aging, which exhibits excellent anti-aging performance of silane.

Abstract: After describing the diseases on hinge joints of the hollow plate and analyzing causes, eight reinforcement measures are put forward and introduced herein accordingly. By means of solid finite element analyzing method, the article conducts a contrastive analysis on a variety of working conditions of those eight reinforcement measures, including the hinge joint stress and transverse distribution parameter. Three ideal methods are selected to conduct further analysis on the reinforcement effect of the hinge joint stress and it is concluded that there is risk in one way steel beam hinge joint reinforcement and two ideal methods are two-way steel beam reinforcement and adding transverse diaphragm in precast phase. From the perspective of fundamental solution to hinge joints, two-way reinforcement exerts more obvious effect on the bridges in service while adding transverse diaphragm is better for newly built bridges. Making it easy for design and construction, this paper offers constructive reference for engineering practice by deducting the vertical arrangement distance of the steel beam, presenting needs to be met by the shear resistance and flexural bearing capacity after verifying reasonable distance, discussing numbers and distance of transverse diaphragm and summarizing the strain of the external prestressed steel beam.

Abstract: This paper reports and discusses the results of experiments performed on masonry barrel vaults strengthened externally with a composite material. The vaults characterized by 125-mm thickness, 2000-mm internal span and 730-mm rise, were built of solid clay bricks and lime mortar. As a strengthening glass fiber grids or carbon fiber grids were used. They were embedded in a polymer-cement mortar at the vaults extrados. The main aim of presented research was to determine load-carrying capacity and examine failure modes of tested specimens. The results of performed tests show that observed failure modes depended on reinforcement ratio of strengthening layer. The specimen strengthened with one layer of glass fiber grid failed due to fibers rupture, whereas the vault strengthened with carbon fiber grid failed due to sliding along a mortar joint just above the abutment.

Abstract: 4 finite element models of ANSYS were constructed according to the masonry wall specimens of the experimental study. A material nonlinear finite element analysis by the finite element calculation software ANSYS on masonry walls strengthened by SGFRP under the horizontal cyclic loads combined with constant gravity loads was performed. The load-displacement curves of the models obtained from ANSYS simulation were described. The ultimate loads of the 3 models strengthened by SGFRP increased significantly, and the fiber length affect the bearing capacity and the deformation capacity of the wall. The results of the nonlinear finite element analysis of the models agree well to the experimental results. Some effective and reasonable reinforcement suggestions are proposed.

Abstract: This study focuses on one of the historic structures located in Shanghai. In order to meet modern occupants’ needs, safety inspection, seismic evaluation and strengthening design for the historic building are carried out. This building, completed in 1930s, was designed without considering the effect of possible earthquakes which cannot meet the current seismic criteria. An analytical investigation of the retrofitted structure is performed. Safety and seismic behavior are analyzed. According to the evaluation, structural performance was better understood which led to the more efficiently use of retrofit methods.

Abstract: Concrete cover thinkness of GFRP to ensure the safety, applicability and durability of the structure is of great significance. Based on studies to 30 the drawing specimens of concrete ,get bond strength of same GFRP diameter,same concrete strength, different concrete cover thinkness. Through the analysis of test data,it is concluded the relationship of the bond strength and the concrete cover thinkness.And basis on the relationship,it is determine the suggestive values on concrete cover thinkness of GFRP.Experimental data and suggestion can provide reference and theoretical basis for the GFRP engineering application and the establishment of the relevant specification.

Abstract: It is the initial problem to choose a reasonable layer-adding project in the layer-adding design for buildings. This paper is to prove, through living example, that choosing the truss structure between layers possesses well economical efficiency, and features space saving, ease of construction and good function of anti-earthquake at seismic regions.