Structural frame selection: case studies of hybrid concrete frames

Hybrid concrete construction (HCC) uses a combination of in-situ and precast concrete and is an example of ‘mixed’ construction, which is the term for an innovative combination of different materials or framing methods. Examples of HCC exist in many countries to fulfil varying structural requirements, so it is not clear why HCC is not better used in the UK. Research was undertaken to gain a better understanding of the selection and use of HCC. Two case study projects were investigated to explore decision-making criteria, the roles of project participants and the challenges particular to HCC. The findings suggest that HCC is selected when measurable cost or programme advantages are not the most important criteria, but where other factors such as satisfying architectural requirements (finish, colour, etc.) or operational demands (such as internal comfort or maintenance) are critical. In both cases, clients and architects were found to be the most influential team members in the frame-selection process.

La construction en béton hybride (HCC) utilise une combinaison de béton in situ et de béton précoulé; c'est un exemple de ‘construction mixte’; cette expression définit une combinaison innovante de différents matériaux et méthodes de coffrage. Il existe des exemples de HCC dans de nombreux pays qui répondent à différentes exigences structurales; on peut donc difficilement expliquer pourquoi la HCC n'est pas mieux utilisée au Royaume-Uni. Des recherches ont été entreprises pour mieux comprendre les choix et les usages de la HCC. Deux études de cas ont été engagées, l'objectif étant d'explorer les critères décisionnels, le rôle des participants à ces projets et les défis particuliers propres à la HCC. Les résultats laissent à penser que la HCC est retenue lorsque le coût mesurable ou les avantages du programme ne sont pas les critères les plus importants et lorsque d'autres facteurs comme la réponse aux exigences architecturales (finition, couleur, etc.) ou d'autres exigences opérationnelles (comme le confort intérieur ou la maintenance) sont critiques. Dans les deux cas, les clients et les architectes sont apparus comme les membres les plus influents des équipes lors du processus de sélection du cadre.

Mots clés: processus de conception, construction en béton hybride, construction mixte, critères de performances, cadre structural     

The building performance sketch

A new approach to the creation of design tools is proposed that addresses the real information needs of designers in the early stages of design of non-residential buildings. Traditional simplified design tools are typically too limited to be of much use, even in conceptual design. The proposal is to provide access to the power of detailed simulation tools at a stage in design when little is known about the final building, but at a stage also when the freedom to explore options is greatest and the ability to improve the design is greatest. The concept of the building performance sketch forms the basis of the proposed design tool. It was derived from consultation with design analysis teams as part of the development of the COMFEN tool for fenestration design. Tools like COMFEN are explored to understand how they were shaped by consultation and how requests from these teams for real-world relevance might shape such tools in the future. The simulation process can effectively utilize some of the as-built, as-occupied and as-managed lessons on behaviours and technical outcomes from the Post-occupancy Evaluation (PoE) of buildings.

Il est proposé pour la création des outils de conception une nouvelle approche répondant aux véritables besoins d'information des concepteurs dans les premières phases de conception des bâtiments non résidentiels. Les outils de conception simplifiée traditionnels sont habituellement trop limités pour être très utiles, même en design conceptuel. Ce qui est proposé est de pouvoir accéder à la puissance d'outils de simulation détaillée à un stade de la conception où l'on sait encore peu de choses concernant le bâtiment final, mais également à un stade auquel la liberté d'exploration des options possibles comme la capacité d'amélioration de la conception sont les plus grandes. Le concept du schéma de performance du bâtiment constitue la base de l'outil de conception proposé. Il découle de la consultation des équipes chargées de l'analyse de la conception dans le cadre du développement de l'outil COMFEN de conception du fenêtrage. Des outils tels que COMFEN sont examinés afin de comprendre comment ils ont été modelés par la consultation et comment les demandes de ces équipes en termes de pertinence réelle pourraient façonner ces outils à l'avenir. Le processus de simulation peut tirer efficacement parti de certaines des leçons, conformes à l'exécution, à l'occupation et à la gestion, en matière de comportements et de résultats techniques, retirées de l'Evaluation Après Occupation des bâtiments.

modèles d'information du bâtiment?bâtiments?processus de conception?outils de conception?début de conception?efficacité énergétique?retour d'information?simulation des performances?évaluation après occupation     

独立学院土木工程专业毕业设计教学改革与实践

毕业设计是土木工程专业人才培养中一个重要的综合性教学环节,独立学院在组织毕业设计中存在一定的困难.福州大学至诚学院土木工程系通过毕业设计前统筹安排、按学生的就业方向分组、全过程与业界密切合作、结合工程实践进行选题、有效的过程控制措施、改进成绩评定方法等方面进行创新,较好地解决了独立学院在毕业实践环节组织中面临的问题,对提高学生的培养质量、促进毕业生就业起到了重要作用.     

多层钢结构化工生产厂房结构设计

对化工项目生产厂房的特点进行了概述,并介绍了某化工项目生产厂房多层钢结构的上部结构设计,包括结构体系选择、结构布置、结构分析及节点设计等。对基于设备的性能设计进行了初步探讨。     

威尼斯城市场所营造研究

威尼斯古城本身是一个复杂的场所系统,其中包含着不同层级的场所形态。本文通过对威尼斯城市场所形态的观察、研究,对其场所空间生长机制、场所结构逻辑以及场所空间特征进行分析总结。     

湿法磷酸萃取工艺对磷石膏晶形的影响

采用模拟湿法磷酸生产方式,通过控制萃取反应工艺条件来控制磷石膏晶形.采用扫描电子显微镜观察晶体形貌,采用激光粒度分析仪测定粒度分布和平均粒径.结果表明:液相中游离的H2SO4含量和P2O5含量对磷石膏的晶体形貌和大小都有影响,前者提高,二水石膏析晶过饱和度降低,磷石膏晶体由薄片状变为粗大的柱状和斜方六面晶体,然后再向聚晶转变,平均粒径变大;后者提高,二水石膏析晶过饱和度升高,晶体由粗大的板状变为柱状,然后再向细针状转变,平均粒径变小.反应温度升高,二水石膏析晶过饱和度降低,晶体尺寸变大,但晶体形状基本不变,均为柱状.从兼顾湿法磷酸生产和磷石膏建材资源化的角度出发,提出优化的萃取反应工艺条件为:液相游离H2SO4质量分数为5％,液相P2O5质量分数为15％～20％,反应温度为80℃,料浆液固比为2.5:1(质量比).     

制氧工艺火灾特点及扑救探讨

分析冶炼、轧钢综合工业中制氧工艺火灾危险性,重点分析氧气—金属火灾的特殊表现形式及火灾后的严重后果.结合具体火灾实例,针对该类火灾大多伴有金属燃烧具体特点,研究高压状态下氧气设备燃烧或燃烧后爆炸的扑救对策,提出火灾控制措施、扑救战术、灭火指挥原则、灭火与救人关系等具体措施与建议.     

Optimal intervention strategies for multiple objects affected by manifest and latent deterioration processes

In the existing infrastructure management systems, optimal interventions strategies (OISs) are determined for objects that deteriorate gradually (manifest deterioration process, MDPs), under the assumption that with appropriate inspection and intervention strategies the probability of failure of object can be neglected. Objects that deteriorate suddenly (latent deterioration process, LDPs), for example, due to scouring during a flood or earth movements during an earthquake are not considered. The determination of OISs for an object that deteriorates due to both MDPs and LDPs requires the consideration of both. The latter, however, means that the probability of failure of the object must be considered. In this article, a Markov model is presented that can be used to determine OISs for multiple objects of multiple types affected by uncorrelated MDPs and LDPs. The model is an extension of the model proposed by Mayet and Madanat (Incorporation of seismic considerations in bridge management systems. Computer-Aided Civil and Infrastructure Engineering, 17:185–193, 2002). In the model, a set of condition states (CSs) is used to describe the condition of objects of each type, where each set is composed of non-failure CSs and failure CSs. The probabilities of going from each non-failure CS to each failure CS are estimated using normalised fragility curves, and the probabilities of going from each non-failure CS to each non-failure CS are initially estimated using the Markov deterioration prediction model of Kobayashi, Kaito, and Lethanh (A Bayesian estimation method to improve deterioration prediction for infrastructure system with Markov chain model. International Journal of Architecture, Engineering and Construction, 1:1–13, 2012a) and later adjusted taking into consideration the probabilities of entering the failure CSs. The use of the model is demonstrated using a road link comprising one road section and one bridge.     

A multi-criteria analysis for bridge sustainability assessment: a case study of Penang Second Bridge,Malaysia

Bridges are a critical part of our nation's economic prosperity and local community well-being. One of the latest trends in bridge engineering is sustainable design, which is designing so that resources are available for many generations to come. Sustainable design considers the ecological, economic and socio-cultural environments and works to balance all three. There are some sustainable infrastructure rating systems (RSs) available, such as Envision that can be applied to bridges. However, no system has been developed that would specifically apply to bridge sustainability assessment. The objectives of this study are first, to investigate bridge sustainability issues from three main aspects: environmental, economical and social; and second, to apply multi-criteria analysis to assess the sustainability of the Penang Second Bridge in Malaysia. A hierarchy structure of the sustainable bridge attributes was developed for each RS, and an analytical hierarchy process method was then applied for the appraisal of the sustainability of a bridge pertaining to the relative attributes. The research involved a committee of Malaysian bridge professionals to support the rational decision-making. The results reveal that the case study has achieved most of the criteria of the sustainability assessments.     

Lignosulfonates: effects on plant growth and survival and migration through the soil profile

The effects of Lignosite^#rm lignosulfonate, a refined lignosulfonate product that is obtained from the sulfite pulping process, on growth and survival of plants were investigated. Following applications of 0, 7500, 15,000 and 22,500 cm³#shm² to 32 plots within a forest plantation, the following were monitored: (1) live aboveground biomass of vascular plants, (2) growth of Douglar fir (Pseudotsuga menziesii) and (3) lignosulfonate migration through the soil profile. Live aboveground biomass of woody vegetation was not affected, and that of herbaceous plants was significantly decreased only at the two greatest application rates. Growth of the Douglas fir trees was not significantly affected. Lignosulfonates disappeared from the soil profile at the same rate regardless of initial concentration. Although it is not practical to use this material as a herbicide in western Washington, land application of lignosulfonates may be environmentally more attractive than traditional disposal methods.