Advanced Materials Research Vols. 255-260

Abstract: The detection of the structur[1]al damage by the method of changes in frequency is limited in detecting single location of the structural damage. This paper try to solve the problems of how to detect the multi-location of the structural damages and the corresponding severity. Therefore, a simple supported large-size reinforced concrete beam in different damage conditions is simulated by the finite element software-ANSYS. Cruves of frequency changes ratio can be maped by the date of the simulation, the locations of damages and corresponding severity can be detection by judging the superposition of the intersections of many curves of the frequent changes ratio. The simulation results demonstrate that the method proposed in this paper cannot only detection the multi-locations of the structural damages accurately, but also analyze the severity of the structural damages qualitatively. Corresponding author: Makun, School of Science, Kunming University of Science and Technology, makun_box@sina.com

Abstract: Reinforced concrete (RC) frame with masonry infill walls is a very common structural system in low and medium rise buildings. The infill walls are usually considered as non-structural components in the design or assessment of buildings. However, many damages in earthquakes have shown that the infill walls can significantly change the structural response to seismic action. Consequently the evaluation of the seismic performance of RC frame with masonry infill walls becomes very important, and also turns to be a major challenge for structure engineers. In this paper a beam-and-column (BAC) macro model for walls is proposed to simulate the masonry infill walls in RC frames. In this model, the masonry panel is replaced by an equivalent rigid frame which is made up of some beam-and-column members. The geometric parameters of each member can be determined simply by equivalent stiffness combined with the original dimensions of wall panel. The physical characteristics are described directly by material properties of wall panel under investigation. To validate the rationality of proposed model, a masonry-infilled RC frame under cyclic reversed loading is analyzed by the proposed model. The results, including crack pattern, load versus displacement relation are then compared with the experiment response. Good agreements are found.

Abstract: This paper presents an experimental study on the response of 18 concrete-filled cold-formed square hollow and double-C steel stub columns under cyclic and repeated loading. The test parameters were (1) infilled materials, i.e. No fill, concrete infilled and mortar infilled columns (2) cross sectional shape and dimension. The effect of lips in double-c section as inside stiffeners is presented. The cyclic tested results indicate the infilled columns possess higher bearing capacity, especially infilled materials with higher strength and non-compact section columns. However, there is no different in ultimate tensile. Moreover, the infilled columns showed larger area under post-yield hysteretic loops leading to better seismic performance. Failure of columns was modified in which the failure mode was shifted from the in-outward local buckling into the outward manner, consequently resulted to higher bearing capacity.

Abstract: Seven groups, total of 31 single-bolted steel-glulam-steel joints, were tested for their mechanical performance. The mechanical properties of single-bolted steel-glulam-steel connection subjected to a load parallel to the grain have been studied. The failure mode and failure mechanism of bolted connections were discussed in detail. It is shown that the failure mode, bearing capacity, stiffness and ductility of the joint are mainly relative to the thickness of the glulam and the diameter of the bolt. Due to the wide application of bolted steel-glulam-steel connections in engineering, the present work can be taken as a reference in manufacture, and design of modern timber structures.

Abstract: To make sure the seismic behavior of outer-jacketing mega frame for storey-adding, a low-cyclic loading test of prestressed concrete beam and a pseudo-static test of Mega frame were analyzed by elastic-plastic finite element program IDARC2D, compared with the test results, skeleton hysteretic curves and restoring force models of structural member were determined. They were used in IDARC2D to study the seismic behavior of mega frame for storey-adding. Some structures designed complied with the Code for Seismic Design of Buildings (GB50011-2001) and correlative literatures about collapse, these structures were reanalyzed after enhancing their seismic measures suitably, collapse were avoided. They are: the main frame of outer-jacketing mega frame in the zone of seismic fortification intensity 8 conforming to seismic grade 1-st, the height of mega frame under 50m conforming to seismic grade 2-nd and that over 50m conforming to seismic grade 1-st in zone of seismic fortification intensity 7. Research achievements will provide reference to engineering application of this structural system.

Abstract: The beam string structure，a new self-balancing system is a combination of a string (Cable), pole and beam-column (beam, arch). Because the beam string structure make full use of tensile properties of high-strength cord, force became more reasonable, transportation became more convenient and construction became more simple for the new self-balancing system. The beam string structure became a new structure with a good value and prospects. In this paper the effects of the static performance of the single truss string structure are researched through analyzing the influence of prestressed cable, pole pitch, blow-span ratio of cable and cross-sectional area of cable using of finite element theory. The results of the reasonable selection of string truss design parameters a valuable reference.

Abstract: Multi-environmental time similarity (METS) stepped forward for solving the key technique of service-life correlation of reinforced concrete (RC) structures exposed in artificially accelerated and real natural environment. Artificially accelerated tests and the similarity relationship between natural and indoor environment are used to estimate the prior information. Inspections of the real structure and concrete specimens are used to update the information and reduce the uncertainty in the service-life prediction. The progress of service-life prediction becomes dynamic and long-term.

Abstract: The stuctural characteristics of large-span annular tensile calbe-truss structural system are introduced. Configuration and classification method for large-span annular tensile calbe-truss structural system are studied based on existing projects and researches, and then several new structural forms are put forward. A series of new composite spatial structures composed of the annular tensile canopy structure and other spatial structure are proposed. The study on classification issues should be beneficial to form-selection, design and construction of such structural system.

Abstract: An analog computation of carbon fiber-reinforced polymer (CFRP)-confined rectangular concrete column under cyclic lateral load is carried out using the finite element method (FEM) and is compared with the experimental results. The comparison indicates that the FEM could accurately predict the behavior of CFRP-confined reinforced concrete (RC) column under cyclic lateral loading. The reinforcement mechanism of carbon fiber sheets on RC columns is studied by analyzing the results calculated with FEM such as the stress-strain of carbon fiber sheets, stirrups, and concrete. The effect of axial compression ratio and the number of layers of fiber sheet on the ultimate bearing capacity and displacement ductility of RC column are studied by the finite element analysis. Part of the conclusion, namely, the effect of the number of layers and setting height of fiber sheet on the RC column, offers the reference and basis for further engineering application. template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Abstract: To simplify the analysis, an elastic perfectly plastic stress-strain law was presented for UHPFRC. The post-cracking behavior was described by the average constant post-crack tensile strength. A strain parameter μ is proposed to evaluate the performance and efficiency of steel fibre reinforcement. 8 rectangular beams were tested in this investigation. Based on the proposed constitutive model, the full history of their flexural moment-curvature relationship for UHPFRC beams was calculated and compared with experimental data on prestressed UHPFRC beams. Good agreement between calculated strengths and experimental data was obtained.