Comparison of key competences of DB clients and contractors in the construction market of the People’s Republic of China

Clients and Design-build (DB) contractors are two key stakeholders in DB projects, and contribute significantly to the successful project performance. This study aims to identify and compare such key competences in the construction market of the PRC. After the survey of available literature and face-to-face interviews, a two-round Delphi questionnaire survey was conducted to identify the key competences of clients and DB contractors in DB projects. Relative importance of these identified competences were ranked and compared. The questionnaire results indicated distinct differences between the key competences of clients and that of contractors. The contractor’s key competences emphasize on DB experience, corporate management capability, building and design expertise, financial capability, enterprise qualification and reputation. While the client’s competences focus on the ability to clearly define the project scope & requirements, financial capacity, contract management ability, adequate staff, effective coordination with DB contractor and similar DB experience. Both clients and DB contractors should clearly understand the competence requirements in DB projects and possess all the necessary competences for the successful outcome of DB projects. The identification of these key competences provides clients and DB contractors with indicators to assess their capabilities before going for the DB option. Furthermore, the comparison of competences for clients and DB contractors will result in better understanding of DB system and improve the communication between these stakeholders.

Sustainable retirement living : what matters

There is a growing demand for sustainable retirement villages in Australia due to an increasing number of ageing population and public acceptance of sustainable development. This research aims to gain a better understanding of retirees’ understanding about sustainable retirement living and their attitudes towards sustainable developments via a questionnaire survey approach. The results showed that the current and potential residents of retirement villages are generally very conscious of unsustainable resource consumption and would like their residences and community to be more environmentally friendly and energy efficient. The cost of energy supply is a concern to majority of respondents. Education is required to residents about recycling household waste and how to use available facilities. A better understanding of retirees’ awareness and attitudes towards sustainability issues helps to improve the sustainable developments of retirement villages in the future.

Prevalence and risk factors of childhood allergic diseases in eight metropolitan cities in China: A multicenter study

Background Several studies conducted during the past two decades suggested increasing trend of childhood allergic diseases in China. However, few studies have provided detailed description of geographic variation and explored risk factors of these diseases. This study investigated the pattern and risk factors of asthma, allergic rhinitis and eczema in eight metropolitan cities in China. Methods We conducted a cross-sectional survey during November-December 2005 in eight metropolitan cities in China. A total of 23791 children aged 6-13 years participated in this survey. Questions from the standard questionnaire of the International Study of Asthma and Allergies in Children (ISAAC) were used to examine the pattern of current asthma, allergic rhinitis and eczema. Logistic regression analyses were performed to assess the risk factors for childhood allergies. Results The average prevalence of childhood asthma, allergic rhinitis and eczema across the eight cities was 3∙3% (95% Confidence interval (CI): 3∙1%, 3∙6%), 9∙8% (95% CI: 9∙4%, 10∙2%) and 5∙5% (95% CI: 5∙2%, 5∙8%), respectively. Factors related to lifestyle, mental health and socio-economic status were found to be associated with the prevalence of childhood allergies. These risk factors were unevenly distributed across cities and disproportionately affected the local prevalence. Conclusions There was apparent geographic variation of childhood allergies in China. Socio-environmental factors had strong impacts on the prevalence of childhood allergies; but these impacts differed across regions. Thus public health policies should specifically target at the local risk factors for each individual area.

The theory and practice on pre-qualification in bidding procedure

资格预审是招标程序中重要环节.通过对投标人的资质和业绩等审查既能保证不符合 要求的投标人尽可能早地退出无谓竞争的行列,避免了大量人力"物力的损失和浪费, 又能促进建筑市场优胜劣汰,提高企业竞争力.同时鉴于目前资格预审和建筑市场存在 的问题,笔者以为通过强化资格预审可以有效推进建筑市场信用体系建设,促进行业健康发展,并且深入探讨了资格预审体系建立的具体对策和措施.

Why the construction quality of design-build projects is not satisfactory : a Queensland study

Design-build (DB) system is well-known to be a popular and effective delivery method of construction work worldwide. It has been demonstrated as superior to the traditional delivery system in regards to time and cost performance. However, it suffers a major flaw, in that the performance of project quality cannot be guaranteed. This paper aims to investigate the underlying factors attributing to the poor quality performance of design-build projects in Queensland. Five major factors were first identified through a comprehensive literature review, which relate to (1) project briefing and scope definition, (2) client’s role and responsibility, (3) procurement selection, (4) contractor’s incentive, and (5) design document quality. A questionnaire survey with 127 DB professionals was conducted to determine how these factors affect various quality criteria, i.e. functional quality, architectural quality, technical quality, workmanship quality, client satisfaction and overall quality. With the architectural quality reduced greatly, the research findings reveal that the DB projects in Queensland have the reduced overall quality compared with traditional projects. The impacts of different factors on the quality performance of DB projects have been closely examined and summarized. The research findings will facilitate project stakeholder’s better understanding of the delivery process of the DB system and provide guidelines to improve the quality performance.

Sustainable education buildings in Australia : a green star review

In order to promote green building practice in Australia, the Green Building Council of Australia (GBCA) launched the Green Star rating tools for various types of buildings built since 2003. Of these, the Green Star-Education rating tool addresses sustainability issues during the design and construction phrases of education facility development. It covers a number of categories, including Management, Indoor Environment Quality, Energy, Transport, Water, Materials, Land Use & Ecology, Emissions and Innovation. This paper reviews the use of the Green Star system in Australian education facilities construction and the potential challenges associated with Green Star- Education implementation. Score sheets of 34 education projects across Australia that achieved Green Star certification were collected and analysed. The percentage of green star points obtained within each category and sub-category (credits) for each project were analysed to illustrate the achievement of credits. The results show that management-related credits and ecology-related credits are the easiest and most difficult to obtain respectively. The study also indicted that 6 Green Star education projects obtained particularly high percentages in the Innovation category. The investigation of points obtained in each category provides prospective Green Star applicants with insights into credit achievement for future projects.

The future of sustainable building assessment tools : a case study in Australia

Sustainability issues in built environment have attracted an increasingly level of attention from both the general public and the industry. As a result, a number of green building assessment tools have been developed such as the Leadership in Energy and Environmental Design (LEED) and the BRE Environmental Assessment Method (BREEAM), etc. This paper critically reviewed the assessment tools developed in Australian context, i.e. the Green Star rating tools developed by the Green Building Council of Australia. A particular focus is given to the recent developments of these assessment tools. The results showed that the office buildings take the biggest share of Green Star rated buildings. Similarly, sustainable building assessments seem to be more performance oriented which focuses on the operation stage of buildings. In addition, stakeholder engagement during the decision making process is encouraged. These findings provide useful references to the development of next generation of sustainable building assessment tools.

Preparation, characterization and in vitro angiogenic capacity of cobalt substituted β-tricalcium phosphate ceramics

Divalent cobalt ions (Co2+) have been shown to possess the capacity to induce angiogenesis by activating hypoxia inducible factor-1α (HIF-1α) and subsequently inducing the production of vascular endothelial growth factor (VEGF). However, there are few reports about Co-containing biomaterials for inducing in vitro angiogenesis. The aim of the present work was to prepare Co-containing β-tricalcium phosphate (Co-TCP) ceramics with different contents of calcium substituted by cobalt (0, 2, 5 mol%) and to investigate the effect of Co substitution on their physicochemical and biological properties. Co-TCP powders were synthesized by a chemistry precipitation method and Co-TCP ceramics were prepared by sintering the powder compacts. The effect of Co substitution on phase transition and the sintering property of the β-TCP ceramics was investigated. The proliferation and VEGF expression of human bone marrow mesenchymal stem cells (HBMSCs) cultured with both powder extracts and ceramic discs of Co-TCP was further evaluated. The in vitro angiogenesis was evaluated by the tube-like structure formation of human umbilical vein endothelial cells (HUVECs) cultured on ECMatrix™ in the presence of powder extracts. The results showed that Co substitution suppressed the phase transition from β- to α-TCP. Both the powder extracts and ceramic discs of Co-TCP had generally good cytocompatibility to support HBMSC growth. Importantly, the incorporation of Co into β-TCP greatly stimulated VEGF expression of HBMSCs and Co-TCP showed a significant enhancement of network structure formation of HUVECs compared with pure TCP. Our results suggested that the incorporation of Co into bioceramics is a potential viable way to enhance angiogenic properties of biomaterials. Co-TCP bioceramics may be used for bone tissue regeneration with improved angiogenic capacity.

Preparation, characterization, and in vitro bioactivity of nagelschmidtite bioceramics

The aim of this study is to prepare Ca, P and Si-containing ternary oxide nagelschmidtite (NAGEL, Ca7Si2P2O16) bioceramics and explore their in vitro bioactivity for potential bone tissue regeneration. We prepared dense NAGEL ceramics through high-temperature sintering of NAGEL ceramic powders. The apatite-mineralization ability, dissolution rate, and human osteoblast response (including cytotoxicity analysis, attachment, morphology, proliferation, and bone-related gene expression) to NAGEL ceramics have been systematically studied by comparing with conventional β-tricalcium phosphate (β-TCP) ceramics. The results showed that NAGEL ceramics possessed more obvious apatite mineralization and dissolution (degradation) and stimulated bone-related gene expression (OCN and OPN) of osteoblasts than β-TCP ceramics. NAGEL ceramics also showed no significant cytotoxicity. NAGEL ceramics supported osteoblast attachment, proliferation, and osteogenic gene expression, with a comparable cell proliferation activity with β-TCP ceramics. These results indicate that novel NAGEL bioceramics with the specific composition of Ca7Si2P2O16, are a promising biomaterial for bone tissue regeneration application.

Copper-containing mesoporous bioactive glass scaffolds with multifunctional properties of angiogenesis capacity, osteostimulation and antibacterial activity

It is of great importance to develop multifunctional bioactive scaffolds, which combine angiogenesis capacity, osteostimulation, and antibacterial properties for regenerating lost bone tissues. In order to achieve this aim, we prepared copper (Cu)-containing mesoporous bioactive glass (Cu-MBG) scaffolds with interconnective large pores (several hundred micrometer) and well-ordered mesopore channels (around 5 nm). Both Cu-MBG scaffolds and their ionic extracts could stimulate hypoxia-inducible factor (HIF)-1a and vascular endothelial growth factor(VEGF) expression in human bone marrow stromal cells(hBMSCs). In addition, both Cu-MBG scaffolds and their ionic extracts significantly promoted the osteogenic differentiation of hBMSCs by improving their bone-related gene expression (alkaline phosphatase (ALP), osteopontin(OPN) and osteocalcin (OCN)). Furthermore, Cu-MBG scaffolds could maintain a sustained release of ibuprofen and significantly inhibited the viability of bacteria. This study indicates that the incorporation of Cu2þ ions into MBG scaffolds significantly enhances hypoxia-like tissue reaction leading to the coupling of angiogenesis and osteogenesis. Cu2þ ions play an important role to offer the multifunctional properties of MBG scaffold system. This study has demonstrated that it is possible to develop multifunctional scaffolds by combining enhanced angiogenesis potential, osteostimulation, and antibacterial properties for the treatment of large bone defects.