Estimating economic losses of midrise reinforced concrete shear wall buildings in sedimentary basins by combining empirical and simulated seismic hazard characterizations     

Pouria Kourehpaz  Carlos Molina Hutt  Nasser A. Marafi  Jeffrey W. Berman  Marc O. Eberhard 《地震工程与结构动力学》2021,50(1):26-42

Studies of recorded ground motions and simulations have shown that deep sedimentary basins can greatly increase the intensity of earthquake ground motions within a period range of approximately 1–4 s, but the economic impacts of basin effects are uncertain. This paper estimates key economic indicators of seismic performance, expressed in terms of earthquake‐induced repair costs, using empirical and simulated seismic hazard characterizations that account for the effects of basins. The methodology used is general, but the estimates are made for a series of eight‐ to 24‐story residential reinforced concrete shear wall archetype buildings in Seattle, WA, whose design neglects basin effects. All buildings are designed to comply with code‐minimum requirements (i.e., reference archetypes), as well as a series of design enhancements, which include (a) increasing design forces, (b) decreasing drift limits, and (c) a combination of these strategies. As an additional reference point, a performance‐based design is also assessed. The performance of the archetype buildings is evaluated for the seismic hazard level in Seattle according to the 2018 National Seismic Hazard Model (2018 NSHM), which explicitly considers basin effects. Inclusion of basin effects results in an average threefold increase in annualized losses for all archetypes. Incorporating physics‐based ground motion simulations to represent the large‐magnitude Cascadia subduction interface earthquake contribution to the hazard results in a further increase of 22% relative to the 2018 NSHM. The most effective of the design strategies considered combines a 25% increase in strength with a reduction in drift limits to 1.5%.  相似文献   

Chloride source delineation in an urban-agricultural watershed: Deicing agents versus agricultural contributions     

Andrew Oberhelman  Eric W. Peterson 《水文研究》2020,34(20):4017-4029

Analyses (n = 525) of chloride (Cl⁻), bromide (Br⁻), nitrate as nitrogen (NO₃-N), sodium (Na⁺), calcium (Ca²⁺) and potassium (K⁺) in stream water, tile-drain water and groundwater were conducted in an urban-agricultural watershed (10% urban/impervious, 87% agriculture) to explore potential differences in the signature of Cl⁻ originating from an urban source as compared with an agricultural source. Only during winter recharge events did measured Cl⁻ concentrations exceed the 230 mg/L chronic threshold. At base flow, nearly all surface water and tile water samples had Cl⁻ concentrations above the calculated background threshold of 18 mg/L. Mann–Whitney U tests revealed ratios of Cl⁻ to Br⁻ (p = .045), to NO₃-N (p < .0001), to Ca²⁺ (p < .0001), and to Na⁺ (p < .0001) to be significantly different between urban and agricultural waters. While Cl⁻ ratios indicate that road salt was the dominant source of Cl⁻ in the watershed, potassium chloride fertilizer contributed as an important secondary source. Deicing in watersheds where urban land use is minimal had a profound impact on Cl⁻ dynamics; however, agricultural practices contributed Cl⁻ year-round, elevating stream base flow Cl⁻ concentrations above the background level.  相似文献   

土壤含水量和磷肥对马铃薯生长发育及抗旱生理的影响     

杨宏伟  刘文瑜  冯焕琴  张俊莲  李朝周 《中国沙漠》2018,38(2):307-314

研究了土壤含水量和磷肥对马铃薯生长发育及抗旱生理的影响,结果显示：（1）土壤含水量的下降导致马铃薯幼苗叶片含水量和叶绿素含量降低,可溶性糖、脯氨酸、丙二醛（MDA）含量、相对电导率（REC）及超氧阴离子（O₂^-·）产生速率升高,抗氧化酶活性增强,株高、茎粗、根长、匍匐茎数、地上部分干重降低,马铃薯块茎重量及块茎淀粉、蛋白质、Vc含量下降;（2）不同水分条件下增施适量磷肥,显著提高了马铃薯叶片含水量、叶绿素含量,相对增强了抗氧化酶活性,降低了相对电导率、MDA含量和活性氧水平,且马铃薯块茎重量及块茎淀粉、蛋白质和Vc含量显著增加。（3）比较包括对照在内的6种磷肥增施量,增施15.3 g·m^-2磷肥对马铃薯幼苗抗旱性及生长发育的促进效果最佳。综上所述,干旱胁迫显著抑制了马铃薯幼苗生长发育,而增施适量磷肥可通过提高渗透调节物质含量和抗氧化酶活性,有效缓解干旱胁迫下马铃薯幼苗叶片的脂质过氧化程度及细胞膜损伤,减轻干旱对生长发育的抑制,增强植株整体抗旱性。  相似文献   

不同水肥处理的沙地玉米生长分析     

赵爱芬  张铜会  赵学勇 《中国沙漠》1999,19(Z1):92-95

在奈曼站农业观测场进行了5种水肥处理的玉米生长试验。结果表明,各处理的玉米株高快速生长期均从6月下旬始,至8月初达最高值。不施肥处理株高和茎粗生长在拔节后期落后于其他处理,早于其他处理停止生长。根量快速增长从6月底开始,至7月底结束,8月下旬根开始死亡,至9月20日,细根数量减少至峰值期的50%。高肥处理的根系增长率高于其他处理,其根密度值最大,不施追肥处理的最小。不浇水的处理在7月初雨季到来时根系开始快速增长。不施追肥的处理早于其他处理7d停止根系的增长。5种不同处理的根系生长动态趋势一致,均为单峰形。施肥量最大的处理(T₁)产量最高,不施肥的处理产量最低。玉米生长期多次灌溉并不能促进生长,相反使产量减少。  相似文献   

不同施氮量对沙地春小麦株穗性状及产量的影响     

崔建垣  张铜会 《中国沙漠》1999,19(Z1):96-98

在内蒙古奈曼旗对沙地春小麦进行了氮肥施量试验。结果表明,不同施氮量(尿素15.0~51.5g·m^-2)对沙地春小麦穗粒数、千粒重、有效小穗数及其百分率、籽粒产量、生物产量的影响具有显著差异,但对成穗数、株高的影响差异不明显。产量水平以施氮量为37.5g·m^-2时最高。  相似文献   

化肥在农业生产中的地位与作用     

段争虎  刘新民 《中国沙漠》1996,16(1):92-96

化肥是提高作物产量的物质基础, 在过去的几十年中, 它在世界农业建设中起过巨大作用。近百年的肥料试验表明, 化学肥料具有和有机质一样的持续增产效果, 在提高作物产量、品质的同时, 还可培肥土壤。随着化肥工业的发展, 化肥的负作用会逐渐减小。  相似文献   

水分和氮肥对冬小麦产量的影响及其调控技术   总被引：1，自引：0，他引：1  

赵国强  朱自玺 《应用气象学报》1999,10(3):314-320

通过对冬小麦进行不同水分等级和不同施氮量的控制试验,利用数理统计和数学分析方法,从水分利用效率和经济效益角度,分析了水分和氮素对冬小麦产量的影响及其相互作用的关系,提出了河南省冬小麦砂壤土的水肥配置模式,经生产检验,这种模式是可行的。  相似文献   

菜田施肥(化肥)对地下水氮污染影响的实验研究   总被引：8，自引：1，他引：7       下载免费PDF全文

董悦安  沈照理  钟佐 《地球科学》1999,24(1):101-104

为研究菜田施肥（化肥）对地下水氮污染的影响,进行了２个土柱模拟菜田施肥（化肥）残存量的实验．结果表明,土柱中化肥残存量的７２．０８％和４７．４４％从渗出水中流出．依据实验数据将实验过程分为３个可能阶段：第１阶段,化肥中的ＮＨ＋４被土壤吸附,并交换出土壤中的Ｋ＋＋Ｎａ＋,Ｃａ２＋和Ｍｇ２＋,使之进入渗出水中;第２阶段,为硝化作用增强的阶段,表现为土柱渗出水中ＮＯ－３的质量浓度比注入水有大幅度增加;第３阶段,为硝化作用强度减弱的阶段,表现为渗出水中ＮＯ－３的质量浓度比注入水增加的幅度减小．  相似文献   

A Closed Loop Wastewater Biorefinery Based on the Recently Introduced SHEFROL Reactor and Two Freely Available Macrophytes     

Tabassum-Abbasi  Pratiksha Patnaik  Shahid Abbas Abbasi 《洁净——土壤、空气、水》2023,51(3):2100287

With an objective to develop a closed loop wastewater biorefinery, the performance of two free floating aquatic weeds water hyacinth (Eichhornia crassipes, Mart, Solms) and salvinia (Salvinia molesta, Mitchell) is explored when either is used as the main bioagent for treating sewage in “sheet flow root level” (SHEFROL) bioreactors. Both the macrophytes prove to be easy to propagate and maintain while they are able to help in achieving significant primary, secondary, and tertiary treatment steps of greywater in a single step. Water hyacinth is able to remove suspended solids, chemical oxygen demand (COD), biological oxygen demand (BOD), total Kjeldahl nitrogen, soluble phosphorous, zinc, copper, nickel, and manganese to the average extents of 81%, 79%, 43%, 41%, 40%, 36%, 34%, and 29%, respectively. The reduction in COD and BOD levels achieved by salvinia is marginally lesser than by water hyacinth but in terms of the removal of other pollutants, the performance of salvinia is comparable to that of water hyacinth. It is possible to convert the dead or harvested plants to organic fertilizer thus making it a closed-loop system with no waste of its own.  相似文献   

基于下一代性能设计理论的全概率抗震性能评估          下载免费PDF全文

董艳秋  王宪杰  王希  杨思昭  周潇凡  龙诗琪  吕龙 《世界地震工程》2020,(2):012-20

对建筑物灾变发生时经济损失和人员伤亡情况做出准确预估是未来建筑结构设计初期需要努力的方向。基于下一代性能化设计理论,通过精细化建模和动力时程分析对结构进行易损性分析,并以此得到抗震性能评估所需的各类地震响应参数,建立RC框架结构全概率抗震性能评估方法。以云南大学力行楼为例,通过地震损失预测得到了该栋建筑的经济损失、修复时间和人员伤亡情况。该方法直观清晰地展示了结果,便于业主及非本专业从业者理解。  相似文献