Assessment of Highway Bridge Upgrading by Dynamic Testing and Finite-Element Model Updating

The Land Transport Authority of Singapore has a continuing program of highway bridge upgrading for refurbishing and strengthening bridges to allow for increasing vehicle traffic and increasing axle loads. One subject of this program has been a short-span bridge taking a busy main road across a coastal inlet near a major port facility. Experiment-based structural assessments of the bridge were conducted before and after upgrading works including strengthening. Each assessment exercise comprised three separate components: (1) a strain and acceleration monitoring exercise lasting approximately one month; (2) a full-scale dynamic test carried out in a single day without closing the bridge; and (3) a finite-element model updating exercise to identify structural parameters and mechanisms. This paper presents the dynamic testing and the modal analysis used to identify the vibration properties and the quantification of the effectiveness of the upgrading through the subsequent model updating. Before and after upgrade, similar sets of vibration modes were identified, resembling those of an orthotropic plate with relatively weak transverse bending stiffness. Conversion of bearings from nominal simple supports to nominal full fixity was shown via model updating to be the principal cause of natural frequency increases of up to 50%. The utility of the combined experimental and analytical process in direct identification of structural properties has been proven, and the procedure can be applied to other structures and their capacity assessments.     

新加坡高职教育在三个层面上的实践及启示

从宏观、中观和微观三个层面剖析了新加坡独树一帜的职业教育理念及具体做法,旨在吸纳其职教精髓,反思我国高职教育的发展,并在国家高职示范项目建设中加以借鉴。     

Ultrathin two-dimensional materials for photo- and electrocatalytic hydrogen evolution

Sustainable hydrogen production via photocatalytic, electrocatalytic, and synergetic photoelectrocatalytic processes has been regarded as an effective strategy to address both energy and environmental crises. Due to their unique structures and properties, emerging ultrathin two-dimensional (2D) materials can bring about promising opportunities to realize high-efficiency hydrogen evolution. This review presents a critical appraisal of advantages and advancements for ultrathin 2D materials in catalytic hydrogen evolution, with an emphasis on structure–activity relationship. Furthermore, strategies for tailoring the microstructure, electronic structure, and local atomic arrangement, so as to further boost the hydrogen evolution activity, are discussed. Finally, we also present the existing challenges and future research directions regarding this promising field.     

"面向河道"的更新设计——新加坡河沿河地区城市更新解读

该文从城市设计的视角,分析新加坡河沿河建筑形态、街区尺度、交通系统、景观系统等方面所采用的设计手法,并提出新加坡河沿河地区的城市设计采用"面向河道"的更新策略.在分析过程中,注重考察和研究这些设计手法对社会经济的发展、传统文化的保护、城市环境的提升所产生的综合效益.     

新加坡佛教建筑的变迁

新加坡佛教主要是由早期的中国移民传入的,他们的民族风俗及宗教信仰形成了新加坡早期宗教信仰,他们建造的早期寺庙建筑成为新加坡传统佛教建筑的雏形.该文在实地调查的基础上,分析了新加坡传统佛教寺庙的类型及实例.随着新加坡佛教的发展及其他因素的影响,现代佛教建筑也大大迥异于传统寺庙,文章探讨了影响新加坡现代佛教发展的因素,及现代佛教建筑的发展,试图揭示其变迁历程.     

新加坡食品较健康选择标志系统经验启示

文章介绍了新加坡较健康选择标志系统基本情况,从规格与使用要求、申请程序、适用范围等进行阐述,指出新加坡作为第一个实施食品FOP标签系统的亚洲国家,其经验做法对中国乃至多数亚洲国家有重要借鉴意义,中国FOP标签系统应具有充分的依据,严格规范申请和使用行为并适度扩大应用范围。     

Modeling the Heterogeneity in Contractors’ Mark-Up Behavior

Individual contractors exhibit different bidding behaviors when confronted with a given set of project decision environment factors, i.e., heterogeneity in the population of contractors. In examining the tenability of the bidder homogeneity assumption, a linear mixed modeling approach is applied to two data sets obtained from Hong Kong and Singapore contractors via a bidding experiment. Two linear mixed models were developed by relating the contractors’ mark-up decision to four project decision environment factors, namely, (1) market conditions; (2) number of bidders; (3) project type; and (4) project size. The results show that not only is there a significant heterogeneity between the Hong Kong and the Singapore contractors in terms of both their preferences (intercepts) and responses (slopes) to the project decision environment factors that affect their mark-up decision, but also that the individual Hong Kong and Singapore contractors have different degrees of sensitivity toward the project decision environment factors (which is reflected in the varying individual-specific intercepts and slopes). These individual-specific parameter estimates have implications for managerial action in formulating a firm’s competitive strategies.     

新加坡滨海舫

NBBJ吸收了来自海上航行的灵感,设计出如同是大自然所塑造的新加坡滨海湾的大帆。在矗立经水冲蚀形成的两个高达245米的高塔被雕琢的岸上,一座被称为“工作生活娱乐”一体化的综合性大楼,包含1111间公寓、餐馆、康体俱乐部、游泳池和网球场的娱乐平台以及停车场所。这个位居世界第10位的扩建,不仅显示新加坡的富庶与丰富多彩,而且将成为未来滨海湾建筑的航标。     

Engineered geothermal power systems for Singapore

Singapore has a high geothermal gradient (～35°C/km) as evidenced by hot springs (70°C) and high heat flow (estimated to be about 130 mW/m²). In this study, ground water models are presented based on AUTOUGH–2 computer modelling. The models show a freshwater lens up to 4.8 km depth under Singapore's land area, whose temperature increases with depth up to 192°C. Three geothermal prospects are identified: an engineered geothermal system (EGS) in hot, wet granite on the main island; an EGS in hot, wet volcanics or granite on Pulau Tekong and hot sedimentary aquifers (HSAs) in the Jurong Formation, both on and off-shore. Geothermal water at 150°C could be used for electricity generation, industrial process heating and desalination. A cost estimate exercise for a district cooling system (DCS) powered by 90°C geothermal water shows that there are significant economic advantages. A feasibility study is required.