984 resultados para civil engineering
Resumo:
The integral variability of raw materials, lack of awareness and appreciation of the technologies for achieving quality control and lack of appreciation of the micro and macro environmental conditions that the structures will be subjected, makes modern day concreting a challenge. This also makes Designers and Engineers adhere more closely to prescriptive standards developed for relatively less aggressive environments. The data from exposure sites and real structures prove, categorically, that the prescriptive specifications are inadequate for chloride environments. In light of this shortcoming, a more pragmatic approach would be to adopt performance-based specifications which are familiar to industry in the form of specification for mechanical strength. A recently completed RILEM technical committee made significant advances in making such an approach feasible.
Furthering a performance-based specification requires establishment of reliable laboratory and on-site test methods, as well as easy to perform service-life models. This article highlights both laboratory and on-site test methods for chloride diffusivity/electrical resistivity and the relationship between these tests for a range of concretes. Further, a performance-based approach using an on-site diffusivity test is outlined that can provide an easier to apply/adopt practice for Engineers and asset managers for specifying/testing concrete structures.
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The rapid population growth is the great motivator for the development of the construction industry and the increased demand for drinking water, resulting in a gradual increase in the generation of solid waste. Thus, this work was carried out in order to recycle industrial and municipal wastes incorporating them into materials for civil construction. The composite produced from water treatment sludge and marble polishing mud, applying lime production waste as a binder, was evaluated for its mechanical performance and its morphological structure. The raw materials were characterized for their chemical composition, mineralogy, morphology, particle size and also the moisture content. With the featured materials nine compositions have been developed varying the content of the water treatment sludge between 25 to 50%, marble polishing mud between 35 to 50% and the lime production waste between 10 to 30%. The composites were subjected to mechanical strength tests, water absorption, chemical and mineralogical composition and morphology. The developed materials presented, on the 3rd day of hydration, maximum strength value of 4.65 MPa, the 7th day 6.36 MPa, on the 14th day 6.74 MPa, the 28th day 5.98 MPa, on the 60th day 8.52 MPa at 90th day 11.75 MPa and 180th day 12.06 MPa. The water absorption values after 28 days of hydration ranged from 16.27% to 26.32% and after 90 days, from 13.57% to 23.56%.
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The job security issue is crucial for the development of construction due to the need to ensure the health of workers, which is done by means of laws and production management. Thus, among various other laws, was enacted NR-18, in order to ensure the worker's minimum conditions for the development work. Despite legislative developments on the subject, they have become ineffective against the excessive number of accidents in the construction industry, bringing the company to greater in ensuring the health and safety of its workers. In view of this need for improvement of working environment in a general appearance, both for purposes of ensuring the law obedience as comfort for workers and quality of the organization, the System Health Management and Safety (OHSMS) is a valid tool demonstrates the evolution of business management, as well as OHSAS 18001 which proposes to ensure the efficiency and integration of a system geared to safety and health at work by means of implements and adaptations of it, in order to bring significant improvements to conditions of work, especially in the form of a new culture to be adopted by the company. Addressing the problem, this paper aims to develop a management system by OHSAS 18001 which is consistent with the terms of NR-18 as it is this integration of OHSMS Management System of the company as a usual practice of that aims at an improvement of work safety in the business of Buildings.
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In Australia, between 1994 and 2000, 50 construction workers were killed each year as a result of their work, the industry fatality rate, at 10.4 per 100,000 persons, is similar to the national road toll fatality rate and the rate of serious injury is 50% higher than the all industries average. This poor performance represents a significant threat to the industry’s social sustainability. Despite the best efforts of regulators and policy makers at both State and Federal levels, the incidence of death, injury and illness in the Australian construction industry has remained intransigently high, prompting an industry-led initiative to improve the occupational health and safety (OHS) performance of the Australian construction industry. The ‘Safer Construction’ project involves the development of an evidence-based Voluntary Code of Practice for OHS in the industry.
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Statistics indicate that the percentage of fatal industrial accidents arising from repair, maintenance, minor alteration and addition (RMAA) works in Hong Kong was disturbingly high and was over 56% in 2006. This paper provides an initial report of a research project funded by the Research Grants Council (RGC) of the HKSAR to address this safety issue. The aim of this study is to scrutinize the causal relationship between safety climate and safety performance in the RMAA sector. It aims to evaluate the safety climate in the RMAA sector; examine its impacts on safety performance, and recommend measures to improve safety performance in the RMAA sector. This paper firstly reports on the statistics of construction accidents arising from RMAA works. Qualitative and quantitative research methods applied in conducting the research are dis-cussed. The study will critically review these related problems and provide recommendations for improving safety performance in the RMAA sector.