589 resultados para dam construction
Resumo:
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.
Resumo:
IT-supported field data management benefits on-site construction management by improving accessibility to the information and promoting efficient communication between project team members. However, most of on-site safety inspections still heavily rely on subjective judgment and manual reporting processes and thus observers’ experiences often determine the quality of risk identification and control. This study aims to develop a methodology to efficiently retrieve safety-related information so that the safety inspectors can easily access to the relevant site safety information for safer decision making. The proposed methodology consists of three stages: (1) development of a comprehensive safety database which contains information of risk factors, accident types, impact of accidents and safety regulations; (2) identification of relationships among different risk factors based on statistical analysis methods; and (3) user-specified information retrieval using data mining techniques for safety management. This paper presents an overall methodology and preliminary results of the first stage research conducted with 101 accident investigation reports.
Resumo:
This article is based on an analysis of narratives of 26 offenders with mental health problems living in the United Kingdom. It explores the impact of an ascribed dangerous status and the construction of the self as moral and responsible in response to this label with reference to the literature on denial, deviance disavowal and other “techniques of neutralization” and Goffman's presentation of self. Two dominant strands are identified in relation to the construction of moral self-hood: “Not my fault” and “Good at heart” narratives. “Techniques of neutralization” are widely drawn on, particularly denial of responsibility in the “Not my fault” narratives that seek to explain anti-social behavior with reference to external forces such as a hostile environment inhibiting their ability to control their lives. In contrast, “Good at heart” narratives draw on the essentially good and moral nature of the inner-self. Both are used as evidence of sharing and adhering to moral norms in order to present an acceptable and credible self.
Resumo:
This paper reports safety leaders’ perceptions of safety culture in one of Australasia’s largest construction organisations. A modified Delphi method was used including two rounds of data collection. The first round involved 41 semi-structured interviews with safety leaders within the organisation. The second round involved an online quantitative perception survey, with the same sample, aimed at confirming the key themes identified in the interviews. Participants included Senior Executives, Corporate Managers, Project Managers, Safety Managers and Site Supervisors. Interview data was analysed using qualitative thematic analysis, and the survey data was analysed using descriptive statistics. Leaders’ definitions and descriptions of safety culture were primarily action-oriented and some confusion was evident due to the sometimes implicit nature of culture in organisations. Leadership was identified as a key factor for positive safety culture in the organisation, and there was an emphasis on leaders demonstrating commitment to safety, and being visible to the project-based workforce. Barriers to safety culture improvement were also identified, including the subcontractor management issues, pace of change, and reporting requirements. The survey data provided a quantitative confirmation of the interview themes, with some minor discrepancies. The findings highlight that safety culture is a complex construct, which is difficult to define, even for experts in the organisation. Findings on the key factors indicated consistency with the current literature; however the perceptions of barriers to safety culture offer a new understanding in to how safety culture operates in practice.
Resumo:
4D simulation, building information modeling, virtual construction, computer simulation and virtual prototyping are emerging topics in the building construction industry. These techniques not only relate to the buildings themselves, but can also be applied to other forms of construction, including bridges. Since bridge construction is a complex process involving multiple types of plant and equipment, applying such virtual methods benefits the understanding of all parties in construction practice. This paper describes the relationship between temporary platforms, plant and equipment resources and a proposed-built model in the construction planning and use of Virtual Prototyping Simulation (VPS) to implement different construction scenarios in order to help planners identify an optimal construction plan. A case study demonstrates the use of VPS integrated with temporary platform design and plant and equipment-resource allocation to generate different construction scenarios.
Resumo:
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.
Resumo:
Columns and walls in buildings are subjected to a number of load increments during the construction and service stages. The combination of these load increments and poor quality construction can cause defects in these structural components. In addition, defects can also occur due to accidental or deliberate actions by users of the building during construction and service stages. Such defects should be detected early so that remedial measures can be taken to improve life time serviceability and performance of the building. This paper uses micro and macro model upgrading methods during construction and service stages of a building based on the mass and stiffness changes to develop a comprehensive procedure for locating and detecting defects in columns and walls of buildings. Capabilities of the procedure are illustrated through examples.
Resumo:
Work in the Australian construction industry is fraught with risk and the potential for serious harm. The industry is consistently placed within the three most hazardous industries to work along with other industries such as mining and transport (National Occupational Health and Safety Commission, 2003). In the 2001 to 2002 period, construction work killed 39 people and injured 13,250 more. Hence, more effort is required to reduce the injury rate and maximise the value of the rehabilitation/back-to-work process.
Design and construction of fixed bed pyrolysis system and plum seed pyrolysis for bio-oil production
Resumo:
This work investigated the production of bio oil from plum seed (Zyziphus jujuba) by fixed bed pyrolysis technology. A fixed bed pyrolysis system has been designed and fabricated for production of bio oil. The major components of the system are: fixed bed reactor, liquid condenser and liquid collector. Nitrogen gas was used to maintain the inert atmosphere in the reactor where the pyrolysis reaction takes place. The feedstock considered in this study is plum seed as it is available waste material in Bangladesh. The reactor is heated by means of a cylindrical biomass external heater. Rice husk was used as the energy source. The products are oil, char and gas. The parameters varied are reactor bed temperature, running time and feed particle size. The parameters are found to influence the product yields significantly. The maximum liquid yield of 39 wt% at 5200C for a feed particle size of 2.36-4.75 mm and a gas flow rate of 8 liter/min with a running time of 120 minute. The pyrolysis oil obtained at these optimum process conditions are analyzed for some of their properties as an alternative fuel. The density of the liquid was closer with diesel. The viscosity of the plum seed liquid was lower than that of the conventional fuels. The calorific value of the pyrolysis oil is one half of the diesel fuel.
Resumo:
Partnering has drawn attention from both academics and practitioners in the construction industry in the context of construction and facilities management. The past decades have seen a number of articles reporting the application of partnering in construction. The Chinese construction industry is one of the largest industries in the world; however, to the authors’ best knowledge, no project in mainland China has adopted this procurement approach in a formal and systematic manner as yet. This study employed a qualitative approach to investigate the factors that support or impede the implementation of partnering in mainland China. The findings indicate that the partnering practice is feasible in the construction industry of China due to the large demand brought about by China’s strong economic growth and government support. However, the implementation of partnering in the Chinese construction industry is being impeded by the restrictions of the current Chinese regulatory framework and tender evaluation framework, the incompatible features of Chinese culture and the general lack of trust. Six strategies that help to facilitate the implementation of partnering in China have been developed. This study offers a useful reference to implement collaborative contracting models such as partnering in developing countries.