Advanced Materials Research Vols. 243-249

Abstract: Earth building is one kind of residential buildings with typical characteristics of materials used locally, natural existence, reasonable construction and low cost in Hanzhong country, and it includes wisdom of working people, and contains plentiful ecological concept, previous architecture experience. The major defect is its low anti-seismic performance, suggestions improving the earthquake resistant capacity of raw-soil structures are put forward from the aspects of enhancing strength and connection, and the preferences for the socialist new rural construction after seismic disasters are provided in the end.

Abstract: The novel passive energy dissipation system named Damped Outrigger System for frame-core tube structure is introduced in recent years, in which the outrigger and perimeter columns are separate, and the vertically acting fluid-viscous dampers connect the end of each of the outrigger walls to the adjacent perimeter column. In this paper, a new simplified model of this structure is studied by considering the damping force and shear stiffness of the core tube and lateral stiffness of the frame with finite element method. The shear correction factor is also employed to consider the shape of the core tube cross section. The numerical example shows that the displacement and the inter-story drift of the structure are reduced effectively under earthquake loads. It means that the damped outrigger is an innovative solution to resisting earthquake loads for frame-core tube structure.

Abstract: The beam-to-beam impact behavior during the progressive collapse progress of reinforced concrete frame structures under severe ground motions is studied in which three types of impact are included, i.e. 1) contact-impact between one-end failed active beam and intact passive beam; 2) contact-impact between two-end failed active beam and intact passive beam, and 3) contact-impact of one-end failed active beam and one-end failed passive beam. As the first step, the initial impact conditions are established based on the principles of the kinematics and the structural dynamics. Then, the velocities of the beams at the impact instant and the locations of the impact would occur are derived. A so-called impact mass factor is introduced in the paper and determined through the principle of equivalent energy. The history of contact force between the beams involved in the impact is evaluated by the Hertz-damp model. The responses of the passive beam are calculated by solving the equation of motion of a generalized single degree of freedom system.

Abstract: Numerical analysis of thermal response and structural response of a suspended pre-stressed steel reticulated lattice shell are conducted for the key nodes of the structure of a gymnasium on software FDS. Two different location of fire source are considered for analysis of response displacements and stresses of the nodes of the pre-stressed lattice shell and three cables. It is shown that the response temperatures of three cables set in the structure have similar variation trend for the fire scene presented here and the fire temperature near inner cable is highest among the three cables. It is concluded that the shell element of center of the structure has largest response stress, and the element above the side cable has larger stress than the shell element above the middle cable when the fire source is located at center of the gymnasium. It is shown that decrease of the pre-stress of the outer cable far away from the fire source is smallest among the three cables set in the structure.

Abstract: In order to study the fire-resistance behavior of the spatial pre-stressed steel structures with large span, the model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed for the key nodes of the structure. For comparison, the air temperatures near the key nodes are also calculated based on the practical formula of large space air temperature rise. The different location of fire source is considered for analysis of response temperature, displacements and stresses of the nodes of the pre-stressed lattice shell. It is shown that the air temperatures was much higher than the response temperatures of the nodes of the lattice shell during a quite period of time after a fire takes place, and the temperature of the cable nodes are also less than the air temperature near the nodes. It is also concluded that not the cable nearest the fire source but the other cables around the cable fail to work first in the fire.

Abstract: Mechanical behavior of a set of ordinary concrete filled steel tubular short column (note as NCSSC) and ceramsite concrete filled steel tubular short column (note as CCSSC) subjected to fire load are experimentally investigated. Effect of the parameters, such as the maximum value of fire temperatures, fire duration on the strength and ductility of the two types of specimens were especially discussed. The test results show that both of the specimens of NCSSC and CCSSC have higher post-fire bearing capacity and better ductility, there was no descent segment in post-fire load-displacement curves of the most specimens subjected to fire load. It was concluded that the maximum response temperature of specimens and fire duration time has great effect on the axial bearing capacity of concrete-filled steel tubular short columns subjected to fire. The maximum longitudinal strain of specimens of CCSSC is less than the corresponding value of the longitudinal strain of NCSSC.

Abstract: A composite FRP trough is analyzed by finite element (FE) method. A modeling of FRP composite trough, which meets the performance requirements, is build in the commercial finite element software ANSYS. The deflection and stresses contours of the FRP trough for the intended application are obtained and discussed.

Abstract: FRP bars were used to improve the mechanical properties of bamboo beams for civil engineering without changing the existing bamboo processing technology in this paper. Three bamboo beams, including one control beam and two FRP-reinforced beams were tested. The effects of various types of FRP bars were compared, including CFRP and BFRP. The results show that the ultimate displacements of reinforced specimens are less than the control specimen. The FRP bars can enhance effectively the cross-section stiffness of bamboo beams. CFRP bars can reduce about 30% strain and BFRP bars can also reduce about 10% strain for the tensile bamboo fiber. The FRP bars in the tension zone can share tensile stress of bamboo fiber. The cross-section stiffness still controls the structure design for the FRP bars reinforced bamboo beams.

Abstract: In order to reveal the performance of steel recycled concrete composite columns, 6 specimens were designed for axial compression loading experiment. And two factors which are recycled coarse aggregate replacement percentage and slenderness ratio of column are taken into consideration. The bearing capacity and load-displacement curves of composite columns are obtained. Based on the test, the failure patterns and the influence of recycled coarse aggregate replacement percentage and slenderness ratio to axial compression load-bearing capacity are analyzed. In the end, the calculation formula for axial compression load of steel recycled concrete composite columns is presented.

Abstract: By means of site test of horizontal-axis wind turbine tower under different working conditions, the paper make a further analysis by DASP system and obtained the acceleration spectrum and characteristic frequency; Again to build finite element model of the tower and calculated it's dynamic characteristics. The measured results and calculative results provide a basis for avoiding resonance and further study of structure dynamic response of wind turbines tower; In addition, it can provide valuable modal parameter data for wind tower design and structural vibration control.