滑坡灾害典型受灾体失效概率计算方法及应用

从系统研究的角度看,滑坡灾害系统包括致灾体子系统和受灾体子系统.滑坡灾害是这2个子系统共同作用的结果.以往的研究主要集中在致灾体稳定性的评价上,没有全面考虑2个子系统对灾害风险的影响,尤其缺少对受灾体子系统的研究.针对这种现状,对一种典型受灾体(框架结构)在滑坡灾害作用下的失效概率计算方法进行探讨:将滑坡灾害致灾模式简...     

Fragility analysis of woodframe buildings considering combined snow and earthquake loading

This paper describes a study to evaluate appropriate percentages of design snow load (factors for use with nominal values provided by the current design load standard for structural design in the United States, ASCE 7-02) when snow load is being taken into account in a seismic fragility analysis. The procedure is illustrated through the development of seismic fragility curves for one and two-story woodframe structures in three locations (Memphis, TN; Carbondale, IL; and Boston, MA) having both moderate snow and seismic hazards. The fragilities are cast in terms of displacement criteria (maximum shearwall drift) with the snow load serving to add seismic weight to the structure. The structures are analyzed using a nonlinear dynamic time-history analysis procedure. The seismic hazard is defined using USGS seismic hazard maps and uncertainty in the seismic hazard at each location is characterized by a suite of ordinary ground motion records. The ground snow hazard is defined through an analysis of data from first-order weather stations at the sites considered. Through a series of multi-hazard convolutions, parametric studies, and the construction of fragility curves, percentages of design snow load are determined for use in constructing displacement-based seismic fragilities and calculating failure probabilities (by convolving with appropriate seismic hazard functions). Practical implications for fragility analysis considering multiple hazards and performance-based design of woodframe structures also are discussed.     

夹芯板结构设计与破坏模式分析

由两个金属面层与塑料泡沫芯层组合的夹芯板,是不同材料最佳利用的组合构件,其结构设计不同于传统的建筑构件。分析了夹芯板的结构特性,讨论了其破坏模式,供实际设计参考。     

浅析商业空间人流动线设计

购物动线是商业空间的生命线,它直接影响着商业运营的成败。商业空间人流动线设计的最终目的就是要激发购物者的购买欲望,设计者要充分重视商业空间中的动线设计,对其进行深入分析,真正把商业动线做到生命线的高度。本文主要从水平人流动线设计、垂直人流动线设计两个方面对商业空间人流动线设计展开研究。     

桥梁抗震加固方法评述

桥梁作为交通生命线的枢纽工程,一旦遭受地震破坏,将会导致巨大的经济损失,并影响震后灾区的救援和重建工作,使得人们对桥梁的抗震性能越来越重视。桥梁抗震性能研究主要有两个方面,一是对新建桥梁采取合理的抗震设计和抗震构造措施;二是对现役桥梁的抗震加固。本文介绍了国内外在桥梁抗震加固方面的一些研究成果,并对桥梁抗震加固的方法进行了总结和评述,以期对我国现役桥梁的抗震加固提供一些参考和借鉴。     

单级式缓降器优化设计

缓降器是一种用于高层建筑的新型救生装置.本文根据单级式缓降器的工作原理及结构特点,提出了这类型缓降器优化设计的数学模型,并应用离散优化设计方法作了实例计算.最后,就设计中有关问题作了简要说明.     

生命线系统相互作用下的震害预测方法

在总结生命线系统地震中相互作用特点的基础上,提出定量评价生命线系统相互作用的三个指标。利用网络分析方法,将生命线系统等效为节点和弧段单元体系,并将节点进一步划分为复杂和简单两种类型,建立考虑相互作用影响下的复杂节点故障树,在此基础上并进一步利用故障树分析方法和地理信息系统的网络分析方法探讨了地震作用下生命线系统网络破坏机理,最终提出了一套考虑相互作用的生命线系统,震害预测新方法。     

Optimum Design System for Steel Cable-Stayed Bridges Dealing with Shape, Sizing Variables and Cable Prestresses

Abstract: A general-purpose, rigorous and efficient optimum design system for steel cable-stayed bridges is developed, in which not only can the cable anchor positions on the main girder and pylon, and the crosssectional dimensions of the member elements be dealt with as design variables, but also the pseudo-loads applied to the cables. A powerful two-stage optimum design method is proposed to determine the optimum values of design variables for the cost minimization problem under stress constraints. At the first-stage optimization process, the cable arrangement and sizing variables are optimized by using the approximate concept and dual method with mixed direct/inverse design variables. Then the optimum values of pseudoloads, which induce the optimum prestresses into the cables, and the optimum sizing variables are determined so as to minimize the total cost of the bridge further by utilizing the sensitivities with respect to the pseudo-loads and a modified linear programming algorithm. The rigorousness, eficiency and practical usefulness of the proposed optimum design system are demonstrated by giving numerical design examples and the investigations of the optimum solutions at various design conditions. The significances of dealing with cable anchor positions and pseudo-loads as design variables are also emphasized.     

基于能量观点的结构安全性与鲁棒性

作为安全的一部分,鲁棒性要求结构在偶然局部损伤情况下不产生与损伤起因不相称的破坏。本文重点是结构鲁棒性评价和实现策略。按照能量观点,结构单元在完全破坏之前应充分吸收或消耗能量。在此基础上,结合结构实际设计能力提出一个新的鲁棒性指标,并以混凝土受弯构件为例作了说明。算例表明该指标能够反映结构破坏过程中的消能能力和对损伤的容纳程度。分析了四种典型材料性能下鲁棒性指标和构件极限应变与屈服应变比值之间的关系。最后,探讨了鲁棒性的实现策略,以期为重点结构及生命线工程减灾提供参考。     

Comparison of algorithms for seismic topology optimisation of lifeline networks

A performance comparison among five optimisation algorithms for the topology design of lifeline network subjected to earthquakes is presented in this study. The topology optimisation model in conjunction with the argument of seismic reliability is firstly introduced for the design of lifeline networks subjected to earthquakes. Subsequently, two quite standard optimisers used in the numerical optimisation, i.e. a genetic algorithm (GA) and a simulated annealing algorithm, are investigated. Their hybrid scheme, entitled a simulated annealing GA that combines the advantages of two standard optimisers, is introduced as well. Besides, an ant colony algorithm and a particle swarm algorithm that have been developed in recent years are explored. Three modelled lifeline networks, including two benchmark networks and one actual network, are used as the numerical carriers that the five optimisation algorithms accommodate. It is concluded that the simulated annealing GA provides an excellent tool with higher efficiency to achieve optimal topology of lifeline networks.     

Life-cycle optimization in the establishment of performance-acceptance parameters for seismic design

A life-cycle formulation is presented for the determination of optimum values of the mechanical properties of a structural system exposed to seismic risk. The resulting values are intended for providing support for the establishment of performance-acceptance criteria and parameters for seismic design. A method is developed for the determination of expected damage functions in terms of simplified reference models of the complex nonlinear systems that are typical of engineering practice. The uncertainties associated with the use of the simplified model to estimate peak dynamic responses of the system of interest are accounted for by means of first-order second-moment probabilistic criteria. An illustrative application of the criteria proposed is presented, together with a discussion about the translation of the results of the optimization studies into engineering criteria and methods expressed in conventional design formats.     

地震作用下多层砖混结构TMD控制及其应用研究

在结构地震反应时程分析基础上,对地震作用下多层砖混结构TMD控制优化设计方法进行了初步探讨;给出了地震作用下多层砖混结构TMD控制优化设计步骤。并用算例验证了该设计方法用于地震反应控制的可行性。     

Reliability of an engineering system under a strong earthquake with application to offshore platforms

This paper presents a method developed for the performance evaluation of an engineering system during a strong earthquake. The seismic reliability of the system is evaluated by considering the different possible failure modes, and seismic reliability of the components of the system. The method is applied to the oil production system at the Statfjord Field in the North Sea. The objective of the analysis is to document the reliability of oil production from the field in the event of an exceptionally large earthquake, and to investigate the effect of spatial variation of earthquake loading parameters on the computed system reliability. It is shown that, with a realistic model of the spatial variation of earthquake motion, there is very little correlation between the earthquake loading parameters at different platform locations. The main consequence of this lack of correlation is that the computed failure probability of the oil production system under the design earthquake is about one order of magnitude smaller than the probability of failure of individual platforms at the Statfjord Field.     

生命线网络系统结构设防水平决策遗传算法

本文以系统可靠度为安全性与经济性的综合指标,以建(构)筑物设防烈度作为优化参数,建立了生命线系统及单元抗震设防水平最优决策的数学模型。并以遗传算法作为优化手段,建立了实用优化算法。     

Numerical analyses in the design of umbrella arch systems

Due to advances in numerical modelling, it is possible to capture complex support-ground interaction intwo dimensions and three dimensions for mechanical analysis of complex tunnel support systems,although such analysis may still be too complex for routine design calculations. One such system is theforepole element, installed within the umbrella arch temporary support system for tunnels, whichwarrants such support measures. A review of engineering literature illustrates that a lack of designstandards exists regarding the use of forepole elements. Therefore, when designing such support, designersmust employ complex numerical models combined with engineering judgement. With referenceto past developments by others and new investigations conducted by the authors on the Driskos tunnelin Greece and the Istanbul metro, this paper illustrates how advanced numerical modelling tools canfacilitate understanding of the influences of design parameters associated with the use of forepole elements.In addition, this paper highlights the complexity of the ground-support interaction whensimulated with two-dimensional （2D） finite element software using a homogenous reinforced region,and three-dimensional （3D） finite difference software using structural elements. This paper further illustratessequential optimisation of two design parameters （spacing and overlap） using numericalmodelling. With regard to capturing system behaviour in the region between forepoles for the purpose ofdimensioning spacing, this paper employs three distinctive advanced numerical models： particle codes,continuous finite element models with joint set and Voronoi blocks. Finally, to capture the behaviour/failure ahead of the tunnel face （overlap parameter）, 2D axisymmetric models are employed. Finally,conclusions of 2D and 3D numerical assessment on the Driskos tunnel are drawn. The data enriched casestudy is examined to determine an optimum design, based on the proposed optimisation of designparameters, of forepole elements related to the si     

An Efficient Method for Evaluating Origin-Destination Connectivity Reliability of Real-World Lifeline Networks

Abstract:   A method of analyzing origin-destination (O-D) connectivity reliability of real-world lifeline networks is proposed in this research. This research is novel because, for real-world lifeline networks with thousands of vertices and links, evaluating O-D connectivity is computationally infeasible with traditional methods, for example, combinatorial methods. It is postulated that the O-D connectivity problem for the actual network can be converted into a virtual problem, while the computation for this problem is fast even for large networks. Hence, it is applicable to real-world lifeline networks. When combined with reliability analysis methods, the proposed method can be used to efficiently solve realistic O-D connectivity reliability problems for real-world lifeline networks. Besides, a rating method is also proposed to rank critical links, that is, links that have great influence on the O-D connectivity. The proposed framework should be valuable for management and reliability analysis of real-world lifeline networks.     

Capturing the spatial and operational interdependencies among building systems using building information modelling

Abstract

This paper presents a novel methodology for extracting interdependencies among building systems and components in order to understand how the effect of a hazard or failure can cascade across building systems and components. The methodology is composed of two parts: (1) a spatial interdependency algorithm and (2) an operational interdependency algorithm. The spatial algorithm separates a building into spaces and then extracts all of the building elements in each space. The extracted elements are clustered into five domain specific groups; architectural, structural, mechanical, electrical, and plumbing systems. After locating the elements within each space, the operational algorithm extracts functional interdependency relationships across the different building systems to link the building spaces to their functional dependencies. Subsequently the resulting spatial and operational model is useful for assessing the propagation of failure through the building’s operation. A case study using a hydroelectric power plant is used to demonstrate the methodology. The risk analysis clustered building elements into five groups where the first group holds the most critical elements and the fifth group holds the least critical elements. Due to flooding, the production of electricity becomes endangered because of the growth in risk exposure of the turbine and connected electrical units.     

刚架结构体系可靠度分析与优化设计方法

本文以结构系统的可靠度作为结构优化设计的控制参数 ,利用分支 界约法寻找结构的主要失效模式 ,用条件概率法求体系可靠度并给出了结构体系可靠度的敏度表达式 ,用最佳矢量法求解结构体系可靠度指标约束下的最小重量优化设计问题 ,最后给出平面刚架计算实例 ,结果表明了本文方法的有效性。     

论城市生命线工程系统的防（火）灾可靠度分析

阐述了保证和提高城市生命线工程系统的防（火）灾可靠度的重要意义。引用了大量火灾及故障案例说明评估城市生命线工程内消防系统的可靠度是一项复杂的系统工程。介绍了当前在不同行业中采用的对复杂系统的可靠度进行评估的一些方法。在对这些评估方法进行比较后介绍了故障树分析法的优、缺点，并指出这种方法完全可以胜任对城市生命线工程系统的防（火）灾可靠度的分析工作。     

Health care facilities demand reliable electrical distribution systems

The electrical distribution system is the lifeline of a hospital. Redundancy, flexibility and reliability are key components to keep in mind during design.