Advanced Materials Research Vols. 243-249

Abstract: With the accelerating process of urbanization, various kinds of unconventional concrete structure increases day by day. According to the Monitoring work achievement of the Memorial Hall for the Battle of crossing Yangtze River, the support system is a new kind of formwork support system that is made up of profiled bars and steel tubes. This support system with high bearing capacity and rigidity is suitable for all kinds of complex structures. The interaction mechanism between cantilever structure and support system and the force distribution rule of the members in structure and support system were studied in the paper. On based of above researches the time-varying model which is made up of the structure and high assembled formwork support system was put up to calculate the bearing capacity of the support system.

Abstract: The aim of updating models is to generate improved numerical models which may be applied in order to predict actual dynamic behaviors of the structure. The approach of numerical predictions to the behavior of a physical system is limited by the assumptions used in the development of the mathematical model. Model updating is about correcting invalid assumptions by processing vibration test results. Updating by improving the physical meaning of the model requires the application of considerable physical insight in the choice of parameters to update and the arrangement of constraints, force inputs and response measurements in the vibration test. The choice of updating parameters is the most important and the numerical predictions should be sensitive to small changes in the parameters. So methods used in model updating places a demand that the mass, stiffness and damping terms should be based on physically meaningful parameters. Using the structure frequency and local modal shape acquired from structural time-history responses, a model updating method of space grid structures was established in this paper. A numerical example is provided to prove the accuracy of this method. The results show that the method can be effectively used to correct the finite element model of space grid structures.

Abstract: At present, the structure of gabled frames is the most extensively-applied structure in the single-storey industrial building and long-span single-storey buildings. The joints of corner are main connecting part of gabled frames, of which the performance directly affects the integral behavior of its structure subject to load. At the same time, the construction of joints also determines its features of the semi-rigid stiffness. In this article, numerical simulation and experimental research are conducted to investigate semi-rigid connection of corner joints in gabled frames with different height-thickness ratios of beam-column web, width-thickness ratios of flange, and height-width ratios in corner joints. The three-folder-line moment-rotation relation model has been established and the expression concerning moment-rotation relation obtained.

Abstract: According to arrangements of local cast-in-situ regions, new precast concrete shear wall (NPC wall) has various types including integrally precast component, component with precast concealed columns and local region of wall by casting in situ, component with precast one end concealed column and the other end by casting in situ and component with all cast-in-situ concealed columns. By finite element analysis for four types of NPC wall and comparing with monolithic cast-in-situ finite element model, the lateral resistance performance of each type of NPC wall were discussed. Compared with cast-in-situ finite element model, NPC wall has rather different lateral resistant mechanism, the load-displacement curves are obviously different, and the horizontal and vertical connections decrease the strength and stiffness. The reasonable arrangement of local cast-in-situ regions can effectively improve the lateral resistance performance of NPC wall. The model composed of all cast-in-situ concealed columns, which has similar lateral resistant performance to cast-in-situ model and shows reasonable load mechanism, should be recommended. Meanwhile, the model consisting of precast concealed column and local cast-in-situ region of wall should be avoided for its poor performance.

Abstract: This paper presents a suitable solution of studying methods on BRBs’ critical load with finite element software．The effects of the relevant factors on the BRBs’ ultimate bearing capacity are investigated, and some practical suggestions for the design and production are provided．

Abstract: T-struts subject to centroid compression buckle flexural-torsionally about their axis of symmetry. When the force is applied at the shear center of the section, T-struts buckle either flexurally or torsionally without coupling of flexure with twisting. Although the buckling load about the symmetry-axis of shear center loading is greater than that of centroid loading, the design capacity of T-struts with defect such as fabrication error, load eccentricity and residual stress decrease by shifting the working line of a T-section compression chord to the shear center. This feature is not well known to designer of constructional steel. This article presents the equivalent slenderness ratio method, a new method for the design of T-struts subject to compressive force, introduces another three methods including the one presented by Shaofan Chen, the one in code and the one in ANSYS, contrasts the calculation results of those four methods and recommends the implementation of equivalent slenderness ratio method in the design of T-struts subject to compressive force.

Abstract: This paper summarizes the results and discussion of experimental studies on corroded, reinforced concrete 4 point beam test specimens (120 mm x 200 mm x 1700 mm) repaired by external bonding of carbon fiber reinforced polymer (CFRP) composite laminates to the tensile face of the beam. The primary parameters investigated in this experimental study were distortion, stress distribution, and ultimate load capacity of the corroded reinforced concrete beams. The results indicate that the load capacity and the rigidity of repaired corroded beams by CFRP were significantly higher than the un-repaired, corroded beams. Beams with a low degree of corrosion damage, repaired by CFRP, were still able to demonstrate good mechanical properties after a short-term fatigue loading.

Abstract: The neutral axis change along with axial load ratio, load angle, section size etc. For the neutral axis of SRCLSC(steel reinforced concrete L-shaped column) is neither plumb with the plane that the moment work on, nor parallel with borderlines of SRCLSC section, it is difficult to get loading capacity and ductility of SRCLSC on biaxial eccentric loading. Based on the plane-section assumption, a method for the nonlinear analysis of complete response process for ductility of 15 SRCLSC..It include 36 sets for load angle, 6 sets for axial load ratio, 3 sets for concrete strength, 3 sets for the content of steel, 2 sets for steel style, 3 sets for stirrup ratio, 3 sets for steel location, 3 sets for section size, 3 sets for stirrup diameter about SRCLSC. The ductile behavior of L-shaped, with calculating 1068 loading conditions,are investigated. It concluded that axial load ratio, load angle, and ratio of the spacing of stirrups and longitudinal reinforcement’s diameter (s/d) are most important factors.

Abstract: Measurement and prediction of absorption of concrete by saturation method is presented. Measurement of absorption of concrete consisting of supplementary cementitious materials was conducted by using vacuum saturation method in accordance to RILEM. Pulverized fuel ash and silica fume were incorporated as partial cement replacements for the preparation of various combinations of cementitious composite systems. Absorption of cement matrix containing ordinary Portland cement, pulverized fuel ash and silica fume at various ages is reported. Based on the experimentally obtained results, analytical prediction models were developed. These models enabled the establishment of isoresponse contours showing the interactive influence between the various parameters investigated.

Abstract: Taking the structure construction cost as the optimized goal, the optimization design is carried on the steel frame structure considering the material plastic, under the explosion load. According to the prevailing steel structure design codes GB50017-2002, the model of steel frame structures is established. The results show that the theory and calculation method is reasonable, which will have a guide in the future.