Advanced Materials Research Vols. 243-249

Abstract: A chamfering rectangular long-span stadium awning is introduced in this paper. To fully understand the spatial co-working property of the cantilevered structure, the function of connecting members in this cantilevered structure is studied. Analysis results identified the formation mechanism of spatial stiffness of the whole cantilevered structure. The research results can shed light on structural study and designing of the same kind.

Abstract: The micro-model, which the brick and the mortar model are separated, is used to analyze masonry. Meanwhile, the mortar is divided into three layers along the thickness direction to obtain the internal mechanical behavior of mortar, and the vertical mortar joint strength is taken as 50% strength of the horizontal mortar joint for considering the poor quality of vertical mortar joint. The compressive ultimate load and failure mode of masonry taken from the finite element analysis result, especially the vertical cracks throughout all bricks and mortar and change of brick and mortar strain, are in agreement with the experimental results. It shows that the micro-model and method adopted in paper are able to effectively apply in nonlinear structural analysis for masonry.

Abstract: In order to determine the strength and deformation characteristics of confined concrete under axial compression of cruciform columns, the test results have been obtained for reinforced concrete cruciform columns through axial compression experiment in the study. After analysis and research, the stress-strain curves of confined concrete have been established, the relational expression between the relatively increased value of the peak strain value of confined concrete in cruciform columns and the stirrup characteristic value was proposed, the descending section of the stress-strain curves of confined concrete was studied, and the variation relationship between the strain ductility coefficient of the confined concrete and the stirrup characteristic value was established. The study results will be provided as reference for the structural design and deformation calculation of cruciform columns.

Abstract: The height from the bridge deck of 5^th main pier to ground surface is about115m, and the depth from the top surface of pier cap to water surface is 65m. Reinforcement measures such as flaw detection by frogman, hole plugged, steel caisson placing, steel caisson modeling, high performance concrete seal cracks perimeter. Reinforcement show that, the effect of high-pressure water jet roughening and hole plugged is well; the steel caisson which weighs about 400t sinking stablely and reaching the intended design location; great liquidity, high performance concrete has good workability , 28d strength is above the design and specification demands, bridge static and dynamic tests meeting the design requirements. The research is important for bridge strengthening, and provides reference for the reinforcement design and construction of the same type bridge.

Abstract: This research attempts to investigate the effect of soil-structure interaction (SSI) on the seismic response of buildings. Computational simulation of a one storey building having different natural periods is performed using time history analysis. Different earthquake motions with different peak ground accelerations (PGA) levels are used as excitations. The ground motion records have been selected in order to ensure low, moderate, and high PGA levels. Moreover, sandy soil with several values of shear wave velocities is used in order to investigate the sensitivity of the seismic response to the velocity variation. An efficient discrete-element model which represents the rotational and horizontal degrees of freedom of the soil mass is considered in the analysis. The coupled equations of motion for the building model with SSI are presented and solved in incremental form using the Newmark's step by step iteration method. In general, the results of the study in terms of response, peak response and peak response amplification show significant changes in considering and ignoring SSI effect. In particular, the numbers of significant cycles of large response amplitude for the building have been increased due to the inclusion of SSI. Moreover, considering the soil flexibility amplifies the peak response of buildings with low natural periods. Furthermore, it has been found that, shear wave velocity variation shows appreciable changes in the peak dynamic response amplification and seems to be insignificant at high natural periods for all levels of earthquake excitations considered.

Abstract: Second-order inelastic analysis should be directly performed in order to overcome the difficulties of the conventional approach, but most of these analyses assume the section to be compact, and do not account for the degradation of the flexural strength caused by local buckling. Since the sections of real structures are not always compact, the analysis should be improved to consider local buckling. The objective of this paper is to investigate the plastic-zone and plastic hinge analysis methods of steel frames accounting for local buckling with nonlinear shell elements and design specifications as AICS-LRFD and Eurocode 3, which may be used as reference for the further study.

Abstract: Influence of strength variability of braces on the weak shear type concentrically-braced steel frames is studied by pushover and nonlinear time history analysis method, which leads to a conclusion that the overstrength of brace has obviously detrimental influence on the seismic performance of the structure, induces stronger seismic reaction and higher seismic risk. Another valuable discovery is that after the area of the braces of weak shear type centrically-braced steel frames are determined according to the requirement of current codes, the designer can intentionally specify the structural steel of comparatively low strength (for example, the 2nd group in the paper taking 70% strength of steel Q235) for the brace, which can provide the structure more excellent seismic performance.

Abstract: In order to study the influence of dynamic response of frame-support-wall structure with openings on floor, six 3D models with different radio of opening are made. According to the finite element mode analysis and dynamic time-history analysis, we know that the location of openings, the size of openings etc. are important to the performance of structure. In order to keep entire structure in good condition, we suggest that the rate of openings should be smaller than 6%~8%.

Abstract: The deficiency of effective length approach and the necessity of second order analysis design on nonferrous engineering steel industrial plant are emphasized. Second order analysis approach by nonlinear finite-element with ANSYS is used to design an industrial plant. The example indicates that second-order effect should not be neglect and the result of first order analysis is not safe enough for industrial plant.

Abstract: Eleven approximate full-size specimens including nine eccentrically compressed columns of monotonic loading and two axially compressed columns of laterally cyclic loading were tested. By a series of comparison experiment of specimens strengthened by high performance ferrocement laminates (HPFL) and no strengthened specimens, it was found that the RC columns strengthened with attached HPFL demonstrated greater degree of improving in load-bearing capacity, in which the carrying capacity increment of the strengthened eccentrically compressed columns with lesser eccentricity was greater than that of the same type of columns with bigger eccentricity under the same strengthening conditions; the strengthening effects of the specimens with lower concrete grade are better than that of those ones with higher concrete grade; the ductility and energy dissipation ability of the strengthened columns were remarkably increased. In this paper, the test results is described, the principle and regularity that this category of strengthening laminate improved the ultimate load-bearing capacity, ductility, cracking behavior and mode of failure etc. of the RC columns are analyzed. The studying results proved that this strengthening measure for RC columns is superior to make the strengthening effect notable, working behavior of strengthened column excellent, strengthening construction easy and economical.