鱼腹式桥

改进型的鱼腹式桥,以其独特的造型,结构受力明确,重又被设计者所青睐。该文对这种桥型的古为今用、结构的组成、受力特点、材料选用作简要阐述。     

浅谈重庆科技馆设计构思

从城市的自然地理特征,结合建筑的自身功能特点,体现建筑的地域性和特殊性。通过对玻璃和石材的解读,展现时城市的地理环境及人文精神的理解和诠释。空间穿插,营造生动的科技体验氛围。     

论城市规划学科体系

城市规划具有两层涵义,既包括城市规划所开展的工作,同时也包含对城市规划工作的相关的科学研究.但是其科学研究往往受到忽视.从城市规划学科发展的双核心模式角度提出了城市规划学科体系的构架,认为城市规划学由理论城市规划学、技术城市规划学和应用城市规划学三部分组成,而科学性内涵是城市规划学科体系架构的核心.     

建筑艺术与科学的比较研究

本文通过对建筑艺术与科学在成就、社会文化中的地位、评判方式及时间感等方面的比较研究,阐明了两者之间的异相,并指出中国当代建筑理论的发展方向是加强科学理性的基础研究。     

负温混凝土科学技术研究再反思

从负温混凝土研究材料科学观点中的细观层次与宏观工程应用技术要求出发 ,反思了负温混凝土科学技术领域自 1994年 10月以来所开展的七项研究工作 ,并说明了负温混凝土科学技术领域所取得的主要成果 ,提出了供讨论的负温防冻剂混凝土今后研究的方向。     

草原人居环境保护与发展三元论 ——以新疆伊犁河谷为例

坚守"山水林田湖草是一个生命共同体"的理念,聚焦伊犁河谷草原人居环境背景资源、活动方式、规划建设的三元一体,将草原人居环境作为三元互动、不断成长的生命体,尝试寻找一种构建荒野、乡村、城市共存融合的草原人居环境保护与发展模式。以客观规律为依据,以主观需求为准绳,寻找及保留草原人居环境演化中相对稳定不变的基因,构建草原人居环境CVA三力评价体系,建立草原人居环境发展CVA量化模型,以求指导草原人居环境未来的保护与发展。推行这种模式不仅可为中国西部地区提供生态安全保障,也将使伊犁河谷成为多种人居环境生命共同体的典范。     

西方学者看中国城市——社会科学及历史学的文献回顾

西方的社会科学工作者及历史学家,对中国城市的研究起步较早、牵涉面较广、视野较高、学科间的观念互用较多,并有较丰硕的成果。本文就西方学者在历史学、地理学、人类学、社会学、城市规划、政治学、经济学、及跨学科中,对中国城市研究的成果,特别是1980年之后的专著,作一简短的文献评介,以收他山之石之效。     

Transport in regional science: The “death of distance” is premature

Transport costs have always been an important dimension in regional science. It is therefore remarkable that regional science and transport economics have developed in a rather unconnected way. Although being distinct, the routes of the two were parallel, and there are signs that the two fields will get closer to each other. This paper further discusses long run trends in transport costs and the potential spatial consequences. The main conclusion is that although in terms of money and time, the performance of transport has improved enormously, many economic activities have not become footloose to the extent as expressed by the notion of death of distance. One of the reasons discussed is the role of transaction costs, some being clearly related with distance.JEL Classification: R0, R4The authors thank the guest-editors and an anonymous referee for helpful comments.     

Numerical evaluation of wind effects on a tall steel building by CFD

A comprehensive numerical study of wind effects on the Commonwealth Advisory Aeronautical Council (CAARC) standard tall building is presented in this paper. The techniques of Computational Fluid Dynamics (CFD), such as Large Eddy Simulation (LES), Reynolds Averaged Navier-Stokes Equations (RANS) Model etc., were adopted in this study to predict wind loads on and wind flows around the building. The main objective of this study is to explore an effective and reliable approach for evaluation of wind effects on tall buildings by CFD techniques. The computed results were compared with extensive experimental data which were obtained at seven wind tunnels. The reasons to cause the discrepancies of the numerical predictions and experimental results were identified and discussed. It was found through the comparison that the LES with a dynamic subgrid-scale (SGS) model can give satisfactory predictions for mean and dynamic wind loads on the tall building, while the RANS model with modifications can yield encouraging results in most cases and has the advantage of providing rapid solutions. Furthermore, it was observed that typical features of the flow fields around such a surface-mounted bluff body standing in atmospheric boundary layers can be captured numerically. It was found that the velocity profile of the approaching wind flow mainly influences the mean pressure coefficients on the building and the incident turbulence intensity profile has a significant effect on the fluctuating wind forces. Therefore, it is necessary to correctly simulate both the incident wind velocity profile and turbulence intensity profile in CFD computations to accurately predict wind effects on tall buildings. The recommended CFD techniques and associated numerical treatments provide an effective way for designers to assess wind effects on a tall building and the need for a detailed wind tunnel test.     

Fatigue crack growth analysis of a square hollow section T-joint

Stress concentration sites are always found at the brace and chord intersection corners of any rectangular welded tubular joint. As a result, fatigue cracks are liable to be initiated and propagated from these corners. In this paper, the 3D fatigue crack growth under the weld toe of a square hollow section welded T-joint is simulated using boundary element method. In accordance with the 3D analyses, fatigue crack growth is predicted using a model based on the Paris’ law and stress intensity factors. Good agreement between the experimental and predicted crack growth and crack shape development is obtained. Based on this crack growth analysis, the fatigue life of a specimen is predicted and compared with the standard S-N curve for hollow section joints. It is found that the standard S-N curve is safe and slightly conservative.