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Zhenxiong Huang Hangtian Xu Jianming Li Nengsheng Luo 《Papers in Regional Science》2020,99(3):705-723
Using 2003–2016 panel data of 278 prefecture-level Chinese cities, we analysed the relationship between highway construction, resource flow, and urban–rural income gap using multiple spatial econometric models. Overall highway construction has narrowed the urban–rural income gap owing to better population mobility and goods flow. However, while goods flow has narrowed the gap, population mobility has aggravated it. A regional difference in the impact of highway construction also exists, that is, the effect is negative in central and western cities, but positive for eastern cities. Moreover, China's “4 trillion” fiscal and currency stimulus plan has strengthened highway construction in narrowing the income gap. 相似文献
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《Construction and Building Materials》2002,16(4):229-239
The results of experiments carried out on structures damaged in the Umbria–Marche earthquake of 1997–1998 are presented. These tests were carried out in situ on masonry panels of various dimensions, which had been strengthened with either traditional or innovative materials and techniques. Concerning traditional methods, panels injected with new limed-based mixes were tested. Other tests were realized by gluing to the wallettes sheets of monodirectional carbon fiber (CFRP) or fiber glass (GFRP) with epoxy resins. In both cases the purpose of the tests was to analyze the effectiveness of the intervention, above all as a technique of seismic-upgrading against in-plane mechanisms of collapse. The results show a significant increase in strength. The experiments carried out allowed to obtain interesting indications for their practical utilization of the studied technique. The injection technique is substantially more efficient when used as a method of repair damaged panels, confirming that a preliminary evaluation of dimension and distribution of voids is necessary before adopting this technique. The experimental work showed that the use of composite materials on double-leaf roughly cut stone masonry is more effective when conducted with other stabilization schemes. The failure of the double leaf roughly cut stone panels strengthened with composite materials resulted from the separation of the two masonry leaves. In both cases the strengthening showed remarkable benefits in terms of increase in strength, providing the masonry with greater shear strength. The increase in stiffness following the intervention, as well as its effect, was also analyzed. 相似文献
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Selin Gundes 《Construction Management & Economics》2013,31(1):59-68
Construction is commonly regarded as an important industry in economic policy making owing to its strong interactions with other sectors in the economy. Using six national input–output (IO) tables compiled to date and economic data for the period between 1969 and 2006, the behaviour of the Turkish construction sector and its relationships to investment, income and to other sectors in the economy are examined. Analysis reveals that the construction industry is losing its propulsive role and that it tends to exaggerate the fluctuations of the economy. The examination of lead and lag times between changes in GNP, construction activity and investments show that public sector spending cuts, in particular, have significant effects on the amplitude and the timing of slumps of the industry. The analysis of linkage indicators indicates that for the whole period under consideration the construction industry has high linkages with only one other industry. Thus the ‘leading’ role it plays in the economy is questioned. 相似文献
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Seismic performance assessment of old dual riveted steel frame–RC wall buildings using the nonlinear dynamic procedure is presented. The study is based on an existing nine-storey building located in Wellington, New Zealand. The building is representative of medium rise steel framed buildings from the first half of the 20th century.A three dimensional numerical model of the building was developed in an inelastic structural analysis program. Nonlinear characterisations necessary for the prediction of the inelastic cyclic behaviours of the structural components were incorporated into the numerical model. Details of the structural configuration and member properties for the analyses were determined from the original engineering drawings, the construction specifications, as-built concrete strength test results and literature on properties of steel sections used around the period the building was constructed. The inelastic time history analyses were conducted using a suite of seven earthquake records relevant to the seismicity of the building's location.Modal properties of the numerical model compare well with results of a physical test conducted on the building. The implemented modelling procedure appeared to have predicted the most probable seismic performance of this type of building, which would not have been captured by other simplified procedures. The assessment also highlighted the adverse effects the characteristics and location of the walls have on the seismic performance of this type of building by introducing significant torsional and vertical irregularities. 相似文献
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Public–Private Partnership (PPP) in construction is gaining in popularity. Although papers published in major journals have documented real cases of PPP projects, there appears to be a lack of systematically summarizing what they have already provided. Consequently, this paper reviewed PPP studies published in the six top journals in the construction field. The objectives are to compare and contrast the findings of the studies so as to provide insights for directing further PPP research and improving the existing practices of PPP projects. To achieve the review objectives, studies were first classified as either empirical or non-empirical. Empirical studies were further grouped under three themes: risks, relationships, and financing. Non-empirical studies were grouped under five themes: financing, project success factors, risks, and concession period. Suggestions for further research are risks, financing, contractual agreements, development of PPP models, concession periods, and strategies in choosing the right type of PPP. 相似文献
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The aim of this paper is to analyse the application of the Peatross–Beyler (P&B) correlation (Fire and safety science—Proceedings of the fifth international symposium, 1997) to calculate the Mass loss rate (MLR) for a pool fire in a confined and ventilated enclosure for a range of conditions.The experimental references considered are the PRISME-SI-D1, D2 and D6 tests (Prétrel et al. in 9th International seminar on fire safety in nuclear power plants and installations, 2005), conducted by the Institut de Radioprotection et de Sûreté Nucléaire.The dimensions of the enclosure used in the experiment are 5 m in length, 6 m in width and 4 m in height. A pool fire, \(0.4\,\hbox {m}^2\) hydrogenated tetrapropylene (TPH, \(\hbox {C}_{12}\hbox {H}_{26}\)), is located in the center of the room. The compartment is connected to the outside through an inlet and outlet. The P&B correlation is implemented as a boundary condition in computational fluid dynamics calculations. The MLR outcome depends on the average \(\hbox {O}_2\) concentration in a predefined volume and the characteristics of the fuel. The influence of the size and location of the predefined volume, the ventilation branch position (at 1 m and 3.65 m from the floor) and the Renewal Rate (\(R_r\)) (\(4.7\,\hbox {h}^{-1}\) and \(8.4\,\hbox {h}^{-1}\)) are studied. Two types of \(\hbox {O}_2\) predefined volumes have been tested: layer and ring. The layer volume is located in the low part of the compartment, the base of the volume spanning the compartment floor. The ring is a volume around the pit. It is assumed for both approaches that the measured \(\hbox {O}_2\) is representative of the available oxygen for the flame. The P&B boundary condition predicts the influence of the vitiation on the MLR. Other methods, such as imposing the MLR expected in open condition, overpredict the amount of injected fuel. The results show that the P&B correlation provides good agreement with the experimental data. The deviation between experimental data and numerical prediction for the average MLR in the best case is ?5.0% with absolute values of 0.004 kg/s and 0.0038 kg/s for the experiment and the simulation respectively for case PRS-SI-D1. The MLR calculation is influenced by the position of the ventilation opening and the \(R_r\). The temperature and \(\hbox {O}_2\) concentration profiles are significantly influenced by the ventilation configuration. These differences are related to the transport of the injected air from the inlet to the floor by density difference. 相似文献
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对砌体结构类型的分析与抗震设计建议 总被引:3,自引:0,他引:3
基于构造柱-圈梁这一特殊形式的约束砌体结构的特点和其在抗震中的显著作用,以及不同配筋砌体构件对配筋率的要求,较好地定义了无筋、配筋及约束砌体构件,并对约束配筋砌体构件在抗震设计中的定位和界定提出了建议,可供修订《建筑抗震设计规范》和《砌体结构设计规范》参考。 相似文献
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汶川地震作用下约束砌体房屋的抗震能力分析 总被引:3,自引:0,他引:3
为验证约束砌体结构的抗震性能,取4栋7层砌体房屋为例进行非线性地震反应分析。4栋房屋中2栋(代号为A1、A2)选自汶川地震影响区的约束砌体房屋,另2栋(代号为B1、B2)为虚拟无筋(或非约束)砌体房屋,除了无任何约束作用的构造措施之外,其他都分别和A1、A2相同。分析中选取汶川地震中基岩和土层场地的共20条地震动作为地震输入。基于分析结果,做了两方面的比较:约束砌体结构房屋地震反应特征和汶川大地震现场调查所见的对比和约束砌体房屋和无筋砌体房屋地震性状的对比。主要结论有:①计算得到的约束砌体房屋在大地震下的震害特征和实际地震相当吻合,结构分析所用的计算模型、恢复力模型和参数取值的可靠性得到验证;②和无筋(或非约束)砌体房屋相比,约束砌体房屋使砌体结构的抗震强度和延性大为改善,具有很好的抗倒塌能力。 相似文献
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综述了地震震级、烈度和抗震设防目标,分析了工程结构破坏的主要情形和多层砌体结构的抗震设计要点,以提高房屋的抗震能力,减少建筑物由于地震而造成的破坏。 相似文献
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根据国家标准《建筑抗震设计规范》编制的原则,通过对多层砖混结构房屋的震害分析,提出了相应的减轻震害,提高整体性的设计方法及构造措施,从而确保建筑工程具备合理的抗御地震的能力。 相似文献
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了研究打包带加固农村砌体结构房屋的抗震性能,应用ANSYS有限元软件对未加固砌体结构房屋及打包带加固砌体结构房屋进行整体动力特性计算分析。研究结构的地震加速度响应,极限位移,结构的应力分布以及破坏现象等等,由此对打包带加固砌体结构的抗震性能做出综合评价。、研究结果表明:打包带加后固结构的裂缝数量增多.宽度较小.应力分布更均匀,整体性能得到了改善.加固后结构的地震加速度响应较小.极限位移要远远小于未加固结构位移.有效地提高结构的抗震性能。 相似文献
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我国村镇地区砌体结构分布广、数量大、抗震性能普遍较差,且具有结构形式多样、无数据和随机性强等特点,获取其建筑信息是实现震害预测的前提和基础,但传统人工检测技术效率低、不经济。为此,提出了一种图像识别与模糊推理相结合的村镇砌体建筑群信息智能获取方法。建立了基于卷积神经网络的砌体建筑图像识别模型,结合图像测量技术获取建筑几何信息;提出了基于模糊推理的砌体结构隐蔽信息确定方法,可有效提取村镇砌体结构墙体属性、构造措施、材料强度等隐蔽属性信息;依据获取的建筑信息与场地信息,分别建立单体结构力学模型与空间地震动场模型,通过结构地震动力响应分析实现村镇区域砌体建筑群的震害预测。最后,对北方地区某村落进行群体建筑信息获取和震害预测,结果表明,基于影像数据的图像识别和图像测量技术可以有效获取村镇建筑结构类型以及外观尺寸信息,提出的模糊推理方法可以高效、准确地识别砌体建筑群的隐蔽信息,进一步通过对震害场景的数值模拟,实现村镇区域群体建筑震害的有效预测。 相似文献
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我国村镇地区砌体结构分布广、数量大、抗震性能普遍较差,且具有结构形式多样、无数据和随机性强等特点,获取其建筑信息是实现震害预测的前提和基础,但传统人工检测技术效率低、不经济。为此,提出了一种图像识别与模糊推理相结合的村镇砌体建筑群信息智能获取方法。建立了基于卷积神经网络的砌体建筑图像识别模型,结合图像测量技术获取建筑几何信息;提出了基于模糊推理的砌体结构隐蔽信息确定方法,可有效提取村镇砌体结构墙体属性、构造措施、材料强度等隐蔽属性信息;依据获取的建筑信息与场地信息,分别建立单体结构力学模型与空间地震动场模型,通过结构地震动力响应分析实现村镇区域砌体建筑群的震害预测。最后,对北方地区某村落进行群体建筑信息获取和震害预测,结果表明,基于影像数据的图像识别和图像测量技术可以有效获取村镇建筑结构类型以及外观尺寸信息,提出的模糊推理方法可以高效、准确地识别砌体建筑群的隐蔽信息,进一步通过对震害场景的数值模拟,实现村镇区域群体建筑震害的有效预测。 相似文献
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The interaction between soil and structure plays a crucial role on accurate determination of structures' seismic behavior. The assumption of fixed base structure has been commonly used in traditional design works, and the interaction between soil and structure is thus often neglected. In addition, historical masonry structures particularly built on elastic soil media may be significantly affected seismic behavior of the structure under earthquakes. In this research, the damage distribution on a historical masonry minaret is numerically investigated under horizontal earthquake ground motion. Alaca Mosque minaret was built in 1271 in Bolvadin district of Afyon province. The historical masonry minaret was chosen as the subject of the study. Nonlinear seismic time history analyses were conducted for fixed‐based and different soil properties under horizontal earthquake ground motion. The horizontal (East–West) component acceleration records of Dinar earthquake (Mw = 6.1) that took place on October 10, 1995, were used during the analyses. Maximum displacement, maximum/minimum principal stresses, and damage ratios were determined by nonlinear analyses performed considering fixed base and soil–structure interaction. The analysis results showed that soil–structure interaction had significant effect on the structural behavior of the minaret, such that, the minaret that was expected to get damage in the case of fixed base did not get any damage when soil–structure interaction was considered. 相似文献
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论述了与配筋混凝土砌块砌体小高层框支结构相关的剪力墙及房屋抗震设计和性能的研究进展概况,介绍了其需要重点研究的几个方面,促进其在抗震设计中广泛地应用。 相似文献