Frame optimization and column design

This paper examines the meaning of the term effective length. The failings of the relevant literature to satisfy the needs of present and future automated design techniques are highlighted.

The different approaches currently available for evaluating effective lengths are reviewed. The eigenvalue method which establishes an overall structure instability criteria is considered. The remainder of the methods all involve expressing the effective lengths of a member in terms of the member stiffness and the stiffnesses provided by the end supports. The importance of obtaining accurate stiffness values representing the member end conditions becomes clear from the formulations obtained and the examples presented in the paper. A method of estimating suitable stiffness values during a typical optimization or automated design procedure is suggested. One of the approaches for evaluating effective lengths is extended to take advantage of the information available from the analysis and to allow for partial restraint against sidesway.

The various methods are compared by testing them on a series of typical frames. Comments on the results are strongly influenced by the consideration that the values obtained should yield structures with the required safety factor.     

基于性能的桥梁抗震设计方法

对我国现行的桥梁抗震设计方法进行了分析,并对基于性能的抗震设计方法的理论进行了阐述,最后分析比较了我国现行桥梁抗震设计方法与基于性能的抗震设计方法,为完善桥梁抗震设计方法提供理论依据。     

Tensions in human-centred design

In human-centred design (HCD), researchers and designers attempt to cooperate with and learn from potential users of the products or services which they are developing. Their goal is to develop products or services that match users’ practices, needs and preferences. In this position paper it is argued that HCD practitioners need to deal with two tensions that are inherent in HCD: they need to combine and balance users’ knowledge and ideas with their own knowledge and ideas; and they need to combine and balance a concern for understanding current or past practices with a concern for envisioning alternative or future practices. Six HCD approaches – participatory design, ethnography, the lead user approach, contextual design, codesign and empathic design – are discussed in order to argue that these different approaches are different ways to cope with the two tensions. In addition, several examples from practice are provided to illustrate these tensions. Moreover, it is advocated that HCD practitioners critically reflect on their practices, their methods and their own involvement, so that they can more consciously follow specific HCD approaches and more mindfully cope with the two tensions.     

建筑抗震设计中的概念

就目前建筑抗震设计概念中常出现的专业术语 ,从地震到抗震 ,场地与地基及抗震设计三方面 ,进行了系统分析与比较 ,指出只有掌握和理解了这些术语 ,才能真正做到“概念设计”。     

Performance-driven design methodology for habitation shell design in extreme conditions on Mars

The research project illustrates how performance-driven design tools can be conducted as an architectural design methodology that suggests an innovative approach to design a habitation shell in extreme environmental conditions without human assistance. This research study attempts to use environmental data revealed by NASA and its habitat design requirements to develop a conceptual design for an innovative habitation form and then simulate it with Mars conditions to analyze the habitation shell's structural behavior according to finite element analysis. In this regard, research phases, including layout configuration, form-finding, and structural analysis, have been conducted to explore a habitation concept implemented with generative design tools as a decision-maker in extreme conditions. In conclusion, two generated typologies of proposed habitation forms will be compared in terms of their structural performance under extreme loads of the martian environment. Within this research project, due to the numerous extreme challenges of design and construction of habitation in extreme conditions using conventional approaches, a performance-driven design methodology will provide a rational and sustainable design methodology to tackle extreme barriers to Mars's environment.     

Advanced analysis for structural steel building design

The 2005 AISC LRFD Specifications for Structural Steel Buildings are making it possible for designers to recognize explicitly the structural resistance provided within the elastic and inelastic ranges of behavior and up to the maximum load limit state. There is an increasing awareness of the need for practical second-order analysis approaches for a direct determination of overall structural system response. This paper attempts to present a simple, concise and reasonably comprehensive introduction to some of the theoretical and practical approaches which have been used in the traditional and modern processes of design of steel building structures.     

Seismic design of outrigger systems using equivalent energy design procedure

An outrigger system is an effective structural scheme that is commonly used in high‐rise construction to increase the stiffness of concrete core walls and to reduce the moment demand within the walls. Despite the on‐going use of outrigger systems around the world, a formal seismic design procedure is yet available. This paper presents an equivalent energy design procedure (EEDP) to design outrigger systems for seismic applications. Three prototype outrigger‐wall buildings of various heights are designed for Vancouver, Canada. Detailed finite element models are developed to assess the seismic performance of the prototype buildings and to assess the safety using the FEMA P695 methodology. The result shows that EEDP is an efficient method to design outrigger systems which results in structures that can achieve sufficient margin of safety against collapse and satisfy multiple performance objectives at different seismic hazard levels.     

Target value design: using collaboration and a lean approach to reduce construction cost

Target costing is an effective management technique that has been used in manufacturing for decades to achieve cost predictability during new product development. Adoption of this technique promises benefits for the construction industry as it struggles to raise the number of successful outcomes and certainty of project delivery in terms of cost, quality and time. Target value design is a management approach that takes the best features of target costing and adapts them to the peculiarities of construction. The concept of target value design is introduced based on the results of action research carried out on 12 construction projects in the USA. It has been shown that systemic application of target value design leads to significant improvement of project performance—the final cost of projects was on average 15% less than market cost. The construction industry already has approaches that have similarities with elements of the target value design process or use the same terminology, e.g. partnering and target cost contracts, cost planning, etc. Following an exploration of the similarities and differences target value design is positioned as a form of target costing for construction that offers a more reliable route to successful project outcomes.     

Patient involvement in Danish hospital design

This paper examines patient-involvement in the process used to design new hospitals. Denmark is in the midst of a phase of hospital building. This recent experience is studied by means of expert interviews with senior practitioners involved in three projects. Examined thematically, the data covers the structure of the design process, identification and ranking of stakeholders, the methods of user-involvement and approaches to accessibility. The paper adds new insight on an under-studied area, design for hospitals and makes recommendations for a change of approach to user-participation in their design. It highlights the difficulties in applying the methods of user-centred design and Design for All in large projects.     

基础隔震结构直接基于位移设计的一体化抗震设计方法

为更加合理地进行基础隔震结构的抗震设计,以使用铅芯橡胶隔震支座(LRB)的基础隔震结构作为研究对象,提出了基础隔震结构直接基于位移设计(DDBD)的一体化抗震设计方法.对于给定地震水准下预先设定的性能目标(即LRB隔震系统最大水平变形和上部结构最大层间位移角),通过所提出的一体化抗震设计方法可以确定LRB隔震系统的力学...     

Analysis of tunnel support design to withstand spalling induced by blasting

This paper presents modeling of rock spalling induced by a dynamic pulse using the finite-discrete element method, for the purpose of tunnel support design to withstand blasting. 1D and 2D model results are compared to analytical spalling equations and field test findings. It was found that only the 2D models are suitable for support design. A distinction between heavy spalling and light rockfall is made based on an estimation of the ratio of the peak stress of the arriving wave to the rock tensile strength. Accordingly, different design approaches are suggested: for heavy spalling a low impedance isolating layer between the tunnel liner and surrounding rock is recommended. For light rockfall, a simplified static FEM analysis procedure is presented.     

铁道工程专业铁路线路毕业设计的实践与探索

铁路线路毕业设计是铁道工程专业采用的一种总结性实践教学环节,对提高铁道工程专业学生对线路设计专业知识的应用能力具有重要作用。针对铁路线路毕业设计,分析了线路毕业设计的特点,研究并探讨了培养和提高学生工程能力的教学改革途径和方法,以期为国内类似专业毕业设计提供借鉴和参考。     

粤港澳三地桥梁抗震设计地震动参数比较研究

对我国广东、香港和澳门三地使用的桥梁抗震设计规范进行了综合比较,比较的内容包括重要性分类、抗震设防标准及目标、场地土分类、设计地震动中加速度反应谱的形式、地震作用的计算等。重点对决定桥梁结构抗震安全性的地震动参数(加速度反应谱)的规定进行了比较。结果表明:三地桥梁工程抗震设计规范各有特色,在地震作用的计算方面有相似之处。AASHTO桥梁规范是真正意义上的基于性态要求的抗震规范,Eurocode 8规范引入了强度折减系数来考虑结构的延性设计,我国的桥梁抗震设计规范主要特点则是多水准的抗震设计法。我国桥梁抗震设计规范虽然有了长足的进步,但在很多方面(例如考虑地震危险性分区)仍可借鉴其它规范进一步改进和提高。     

核电厂抗震设计谱确定方法分析

抗震设计谱是核电厂抗震设计的主要依据。核电设计谱的表达多采用直线分段式方法,一般由固定的设计谱形与具有一定保证概率的地震动幅值共同组成。简要回顾核电设计谱的发展历程,对核电设计谱的主要确定方法进行比较和分析,探讨统一危险性谱在核电抗震应用中的问题。基于近期发生的强震动数据库,按4种设计谱标定方法分别计算设计谱以及反映设计谱稳定性的规准伪速度谱谱比曲线。分析结果表明,基于双规准反应谱的设计谱在速度控制段的谱值明显偏高,直接基于伪速度谱的设计谱标定方法具有稳定性优势。最后,为我国核电设计谱进一步研究工作的开展提出些许看法和建议。     

Low-energy design: combining computer-based optimisation and human judgement

Simply minimising the heat loss from a building will not necessarily lead to an exemplary low-energy design: overheating may occur, leading to a large amount of cooling energy being used, and the shape and form of the design may not fit with other sensitivities and elements of the design brief. This paper couples a population-based optimisation algorithm (a genetic algorithm) to a dynamic thermal model with the idea of identifying large numbers of distinctly different low-energy designs. These designs are then presented to the user in the form of a visual summary for judgement as to potential use.

In order that sufficiently different designs are evolved, and the thermal model can be run over a complete year on an hourly grid, several adaptations to the genetic algorithm have had to be made.

The approach is illustrated by the design of a community hall. An extensive range of design possibilities is identified which achieve low-energy status by greatly different means with some concentrating on reducing losses and others on maximising their use of causal gains, including solar gains.     

The Fortress, the panoptic, the regulatory and the animated: planning and urban design approaches to safer city centres

This paper discusses planning and urban design approaches to making city centres feel safer. Planning and urban design inter alia contribute to the creation of the city-centre landscape and are intimately concerned with the design and management of public space. Perceptions and feelings of personal safety are prerequisites for a vital and viable city centre; if a city centre is not perceived to be safe, those with choice will choose not to use it, making it less safe for those with fewer choices. This paper therefore identifies and outlines four planning and urban design approaches to making city centres feel safer: the fortress, the panoptic, the regulatory and the animated.     

Q-PLOS,developing an alternative walking index. A method based on urban design quality

The Level of Service (LOS) is a measure to evaluate the degree of accommodation of different transport modes in a given infrastructure (road, railway, street, etc.). While the last decades have seen a growing interest regarding the use of level of service for managing and planning private and public transport infrastructures, shortcomings appear when it is used in the context of pedestrian mobility (i.e. the complexity of pedestrian mobility in terms of behaviour and the consideration of urban design factors associated with pedestrianisation). This paper aims to gain insight into the abovementioned issues by developing an alternative walking index, the Quality of Pedestrian Level of Service (Q-PLOS) method. This novel method is based on the quality of urban design for pedestrian and its relationship with walking needs. The city of Granada (Spain) provided the empirical focus. The paper found that the Q-PLOS was a more accurate measurement of pedestrian mobility characteristics. This was based on the relevance of specific factors linked to urban design together with public preferences about them. Finally, the obtained high-detailed outputs provide a platform to increment the effectiveness of level of service specifically for pedestrians that want to access to a public transport stop.     

浅析城市设计和生态城市

从城市设计的历史和概念入手,介绍了现有较成熟的六种城市设计方法,通过理论和实例对现代城市设计的两个趋势进行了研究,即从文化和艺术的角度发展城市以及城市设计中的生态观念,最后指出了未来城市设计中应该考虑的三个方向。