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对1/4比例的9层组合砌体房屋模型进行了拟静力试验,得到此类结构的有关抗震性能指标,在此基础上,对试验模型和原型房屋进行了非线性地震反应分析,探讨了此类房屋的动力反应特性,对组合砌体房屋的抗震能力作出了较为客观的评价,并对应采取的抗震措施提出了建议。 相似文献
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《世界地震工程》2016,(1)
气体绝缘金属封闭开关设备(GIS)是高压配电装置常见型式,以GIS高压开关设备为研究对象,基于拟合标准反应谱的人工地震动合成理论,生成符合高压电气设备抗震试验要求的人工地震波。同时以实震记录El-centro地震波作为试验配合波形,进行了GIS高压开关设备原型结构的模拟地震振动台试验,研究其抗震性能,寻找设备抗震薄弱点,为高压电气设备的抗震设计提供依据。试验表明:GIS高压电气设备具有较好的抗震性能,在0.4g地震激励下该设备的抗震性能能够满足规范要求,但其套管处加速度综合放大系数及位移值均大于设备主体,为该电气设备的薄弱点,设计时应在套管处采取必要的加强措施提高其抗震能力,防止在地震激励下高压电气产生破坏。 相似文献
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以四川石油管理局管辖的输气长输管道的抗震安全评价为例,说明了评价这种大管线的方法以及对种薄弱环节应采取的抗震措施。所提出的方法和措施对其它长输管线的抗震问题亦有借鉴意义。 相似文献
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钢筋混凝土结构的抗震设防目标,通俗的说法是“小震不坏,中震可修、大震不倒”,具体来说是“三水准设防目标”。三个水准的设防目标是通过两阶段设计来实现的。钢筋混凝土结构抗震设计的基本步骤:把握好抗震概念设计,采取双指标控制条件,使结构和结构构件既满足抗震承载力要求又满足变形要求,同时保证加强抗震构造措施,使结构有足够的结构延性,最终实现“三水准设防”目标。 相似文献
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为加强超限高层建筑结构的抗震性能,最大程度减小地震损失,以某一超限高层建筑为对象,对其结构抗震设计的加强措施和建议进行详细分析。在小震作用下运用pkpm软件MIDAS/Building对建筑结构进行弹性计算对比分析,证明弹性计算的可靠性;借用SATWE对结构在中震或大震作用下不同构件的承载力和截面进行验算;采用midasbuilding软件对该超限高层建筑进行罕遇地震作用下的静力弹塑性分析。根据不同震级下建筑结构线弹性分析结果,对建筑主体结构、结构抗震和地基基础进行加强设计,从中归纳出整体结构的抗震加强措施和建议,说明该超限结构能满足规范的设防要求,是安全可靠的。 相似文献
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Gtz Schroth Luciana Ferreira Da Silva Marc‐Andree Wolf Wenceslau Geraldes Teixeira Wolfgang Zech 《水文研究》1999,13(10):1423-1436
The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi‐strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open‐area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for palmito, respectively, 0·5% in the cupuaçu monoculture and 3·1% in the fallow. With more than 20% of the open‐area rainfall, the highest stemflow contributions to the water input into the soil were measured in the palm monocultures and in the fallow. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities. 相似文献
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M. A. Kahn 《洁净——土壤、空气、水》2000,28(2):95-101
Red tide, a recurrent phenomenon has become conspicuous in several Kashmir lake ecosystems since 1991. The responsible organism (Euglena pedunculata), a rare flagellate rediscovered in the Kashmir Himalaya (Khan 1993) caused first and unprecedented red tide outbreak, constituting a maximum of 96% of resident numerical phytoplankton density in Dal Lake. At present, conflicting hypotheses exist on the generation of causal assemblage(s) imparting redness to waters: Jeeji Bai (1991) linked its origin to acid precipitation – a fallout of burning oil‐fields during the Gulf War – whilst Khan (1993) holds local factor(s) responsible. Field/experimental studies support the latter contention that the influx of untreated sewage, in unison with warm temperatures, high levels of PhAR, iron and interruption to hydrological flow‐pattern together with absence/or reduction in grazing activity created conducive environmental milieu for red tide outbreak. Dal Lake “red tide” drifted the bloom‐inoculum to other waters, including Lake Wular, where additional ecological niches were carved out, threatening the aesthetic value and biological diversity of Kashmir lakes. Ecological monitoring indicates frequent seasonal red tide occurrence in Dal Lake (including summer‐autumn event of 1998) which testifies its unabated eutrophication status. Further studies are needed on ecological adaptability and biogeographic distribution of this rare and unique red tide‐causing flagellate. 相似文献
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