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按不同设防烈度设计18层剪力墙结构,计算不同设防烈度下的结构工建成本。对比可知,设防烈度Ⅷ度以下,设防水准提高一个等级,土建成本增加比例小于6.07%,增加成本占房屋售价的比例小于0.593%。剪力墙结构土建成本较小的增加,可获得设防水准一个等级的提高。从另一个角度说,在减少建筑面积很小的情况下,房屋的抗震设防水准可获得一个等级的提高。 相似文献
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国家标准《中国地震动参数区划图》(GB18306-2015)已于2016年6月1日起开始实施。新一代区划图的实施,使得建筑的土建成本相对于之前有所变化。运用结构设计软件按照相关规范规定的最低标准完成剪力墙结构构件在不同地震动参数情况下的内力和配筋计算,并根据最新的建设工程预算定额和估价表,对上述情况进行施工图预算并在经济性方面进行系统的对比分析。结果表明:随着设防烈度的提高,剪力墙结构土建工程每平米成本上浮的比例也会增大,且随着设防烈度的提高,土建成本的增长比例越来越大。 相似文献
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随着我国地震工程学的发展,烈度的应用范围渐渐发生了变化。通过整理半个多世纪的历史地震震害数据,发现整体趋势是,低烈度区的同类结构基本完好比例增加,其他破坏等级的比例下降,高烈度区同类结构的毁坏比例增加;收集近些年发生的汶川地震、芦山地震和鲁甸地震的部分震害数据,发现同一烈度区,设防、未设防的和不同设防等级的结构震害差别较大。如果烈度表达的是地震后果,则据这些后果平均水平判定的烈度应有不同,反证了烈度的含义是通过震害反映的地震作用。因此,借助不同建筑类型、不同设防等级的结构判定烈度时,需要相对统一的标准。由于我国丰富的震害资料来源于未设防结构,建议通过某个烈度下的不同设防标准、各类结构、各震害等级的平均震害指数和(或)破坏比与未设防同类结构的平均震害指数和(或)破坏比的统计关系,建立未设防结构对应的平均震害指数和(或)破坏比的调整系数,可据设防结构震害判定烈度。 相似文献
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考虑到《中国地震动参数区划图》(GB 18306—2015)(中华人民共和国国家质量监督检验检疫总局等,2016),提出了双参数调整原则,即对场地地震动峰值加速度和反应谱特征周期进行同时调整,以确定设计地震动反应谱,这势必会增加结构的土建成本。因此,基于Ⅱ类场地,对抗震设防烈度7度(0.15 g)的剪力墙结构在不同场地类别下的地震动参数进行推导。采用单一控制变量法,对某12层剪力墙结构按不同抗震设防烈度和不同场地类别进行设计,使其满足规范最低标准,计算相应的钢筋和混凝土材料用量;根据现时市场定额,比较分析单一地震动参数变化时的土建成本,研究结果可为工程实践提供一定参考。 相似文献
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地震易损性分析是评估结构地震灾害损失的关键。应用PKPM软件设计了不同设防烈度的6个16层剪力墙结构。应用增量动力法求得各结构在不同罕遇烈度地震作用下的最大层间位移角,回归分析给出了最大层间位移角与地震作用加速度峰值的关系式。以最大层间位移角为整体性能指标,进行结构地震易损性分析,给出了结构地震失效概率关于地震作用加速度峰值的计算公式。计算得到了不同设防烈度剪力墙结构在罕遇地震作用下的震害矩阵,为评估框架-剪力墙结构的地震灾害损失,提供了基础数据。 相似文献
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In agriculture, water is a fundamental but increasingly scarce resource that requires careful use. The goal of fostering water-savings could be achieved with a regulation that imposes more efficient irrigation systems. This might represent the only policy option when water withdrawals cannot be controlled and when the operational context does not allow filling the information asymmetry between policy makers and farmers with metering systems, quotas, or market rights. The regulation could involve higher costs for farmers. However, it could represent an opportunity to increase farm revenues if consumers are willing to pay a higher price for goods produced according to an ecological standard. Knowledge of the costs and possible benefits is relevant because it would enable us to understand the potential cost allocation among stakeholders according to how the policy is designed. The results of this study indicate that the management cost of a sustainable irrigation system could be at most 48% greater than that of a wasteful, traditional system. However, the higher costs of the regulation could be compensated for because consumers are willing to pay 6.8% more for less intensive water-use agricultural products. Therefore, a regulation associated with the promotion of hypothetical water-saving label can be the best strategy to irrigation efficiency in agriculture. 相似文献
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As one of the main load-carrying components of cable-stayed bridges,bridge towers are typically required to remain elastic even when subjected to severe ground motions with a 2%-3%probability of exceedance in 50 years.To fulfill this special requirement imposed by current seismic design codes,reinforcement ratios in the bridge towers have to be kept significantly higher than if limited ductility behavior of the tower is allowed.In addition,since the foundation capacity is closely related to the moment and shear capacities of the bridge tower,a large increase in bridge construction cost for elastically designed cable-stayed bridge is inevitable.To further investigate the possibility of limited ductility bridge tower design strategies,a new 1/20-scale cable-stayed bridge model with H-shaped bridge towers designed according to strong strut-weak tower column design was tested.The shake table experimental results are compared with a previous strong tower column-weak strut designed full bridge model.A comparison of the results show that ductility design with plastic hinges located on tower columns,i.e.,strong strut-weak tower column design,is another effective seismic design strategy that results in only small residual displacement at the top of the tower column,even under very severe earthquake excitations. 相似文献
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In an effort to reduce wind effect on rainfall catch to a minimum level, Chang and Flannery (2001. Hydrological Processes 15 : 643–654) designed two spherical orifices to modify the standard gauge and other gauges in use today. Because of the spherical shape, the two orifices will catch rain with an effective diameter always equal to the actual diameter, regardless of wind speed and direction. This report covers the testing of spherical gauges at two different locations, one at the City Landfill, Nacogdoches, TX, and the other at the NWS Forecast Office, Shreveport, LA. Based on 131 storms at Nacogdoches and 94 storms at Shreveport, observed between May 1998 and February 2001, the results showed: (1) spherical gauges recorded an average 6–9% greater than standard gauge and 3–4% less than pit gauge, only 1–2% less than reported in the original study; (2) the catch of spherical gauges was not significantly affected by three gauge heights at 0·91, 1·83, and 2·74 m above the ground, but catch by the standard gauge decreased with increasing gauge height; (3) improvements of the spherical gauges were most significant for larger storms and for winds at higher speeds; (4) the spherical gauge with cylinders recorded 1–2% more rainfall than the spherical gauge with vanes; and (5) correlation coefficients between catch deficiencies and wind speed were low and weak because of the distance and height of the existing wind sensor. Owing to greater surface wetting and evaporation loss, the spherical gauges may underestimate rainfall catch by standard gauge for small storms (generally less than 5·0 mm), especially on hot summer afternoons and for smaller storms. However, the underestimates do not overshadow the merits of spherical gauges, because the differences are too small to be of hydrologic significance. Using polyethylene or other synthesized materials to construct spherical orifices may improve the catch for small storms. The results of the study agreed with the previous claims that spherical gauges are effective in reducing wind effects on rainfall measurements. The spherical gauges could greatly improve the accuracy of hydrologic simulations and the efficiency on the designs and management of water resources. They are suitable for large‐scale applications. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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震后建筑群修复施工阶段工程造价动态控制比其他阶段更具有变动性,需要高精度和高灵活性的预控系统的运用才能保证工程造价不出现偏差。在此文中,设计震后建筑群修复施工阶段工程造价动态预控系统。相关人员可在用户登录模块进入系统界面,在系统的工程信息管理模块中,采用改进遗传算法构建震后建筑群修复工程造价模型,完成震后建筑群修复工程造价动态预控系统的设计。实验结果验证,本文所设计的基于改进遗传算法的造价动态预控系统能够有效实现震后建筑群修复施工阶段的工程造价动态预控,伴随造价样本数目的增多,误差率会逐渐降低,预控性能较好;且预控灵活性始终大于95%,使用局限性仅有0.04,实用性较高,能够为震后建筑修复施工部门的工程造价控制给予借鉴。 相似文献
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本文针对汶川大地震前位于源区特殊部位的成都台NE测向地电阻率的大幅度趋势下降过程, 以测区地表地电阻率变化与测区内部介质(真)电阻率变化的物理联系的理论为依据, 模拟了测区底层因受孕震过程影响出现一个电性变化区域, 计算了该区域电阻率变化的程度以及其上界面逐步(向上)扩展对成都台地表装置系统地电阻率变化的影响。 结果表明, 当底层电性变化区域介质电阻率发生某种减小时, 在成都台的装置系统上测到的地电阻率确实会下降, 下降的幅度随着变化区域上界面向上的扩展而单调增大; 变化区域电阻率减小的程度越大, 这种影响也会更显著。 对于成都台7%的趋势下降异常而言, 从数值模拟的角度来看, 变化区域的电阻率变化可以取多种可能的量级, 不过不同量级的变化与其相应的上界面位置有关, 例如: 底层变化区域真电阻率下降幅度达20%左右时, 变化区域上界面到距地表430 m时, 地表装置视电阻率下降可达1%, 其影响才开始为地表装置系统所识别; 而要解释地表视电阻率有7%左右的视电阻率下降变化, 则要求这个变化区域的上界面上升到距地表122 m左右。 相似文献