排序方式： 共有3条查询结果，搜索用时 14 毫秒
1
1.
2.
The influence of static shear stress on undrained cyclic behavior of nonplastic and low-plasticity silts has been studied
by means of undrained cyclic torque-controlled ring-shear tests. The cyclic and post-cyclic behavior of silty soils assumed
on sliding surface were investigated to assess the liquefaction potential and cyclically induced deformation of silty slopes.
Six different initial static shear stresses corresponding to slope angles from 0° to 25° were examined. To better understand
undrained cyclic behavior of silt governed by a change in clay content, three different mixtures were achieved by mixing of
nonplastic silt with 0%, 10%, and 20% of commercially available clay. These tests were conducted to simulate field conditions
prior to earthquake with initial static shear stresses corresponding to slopes and those with no initial static shear stresses
of level grounds. The gradual loss of mobilized undrained cyclic shear resistance after failure and pore water buildup in
relation to a number of cycles was observed. The undrained response of the soil to cyclic shear stress loading with the constant
amplitude revealed the significant effect of the initial static shear stress on the excess pore water pressure generation
and post-failure shear resistance. Test results showed that an increase in the initial static shear stress at the given initial
effective normal stress is associated with an increase of mobilized shear resistance at its peak state; however, the actual
resistance to liquefaction diminished for both nonplastic and low-plasticity silts. During both cyclic and post-cyclic stages
of loading, distinctly different types of shear deformation were identified. In order to evaluate mobility of landslides,
a modified conventional brittleness index for seismic loading, , was proposed and used to characterize unlimited deformation of silts. 相似文献
3.
In this paper, a contribution of various types of masonry infill to the behaviour of reinforced concrete frames under lateral loads is presented. As a part of the bigger project, ten one‐bay, one‐storey reinforced concrete frames were designed according to the EC8, built in a scale 1:2.5, infilled with masonry and tested under constant vertical and cyclic lateral load. The masonry wall had various strength properties, namely, high strength hollow clay brick blocks, medium strength hollow clay brick blocks and low strength lightweight autoclaved aerated concrete blocks. There were no additional shear connectors between the masonry and frame. The results showed that the composite ‘framed wall’ structure had much higher stiffness, damping and initial strength than the bare frame structure. Masonry infill filled in the load capacity gap from very low (0.05%) to drifts when the frame took over (0.75%). The structures behaved as linear monolithic elements to drifts of 0.1%, reached the maximum lateral capacities at drift of 0.3%, maintained it to drifts of 0.75% and after that their behaviour depended on the frame. Masonry infill had severe damage at drift levels of about 0.75% but contributed to the overall system resistance to drifts of about 1%. At that drift level, the frame had only minor damage and was tested to drifts of about 2% without any loss of capacity. Improvement of the ‘infill provisions’ in the codes could be sought by taking into account the contribution of a common masonry that reduces expected damages by lowering the drift levels. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
1