工程成本预算 毕业论文外文文献翻译.doc

外文翻译Construction projects, private and public alike, have a long history of cost escalation. Transportation projects, which typically have long lead times between planning and construction, are historically underestimated, as shown through a review of the cost growth experienced with the Holland Tunnel. Approximately 50% of the active large transportation projects in the United States have overrun their initial budgets. A large number of studies and research projects have identified individual factors that lead to increased project cost. Although the factors identified can influence privately funded projects the effects are particularly detrimental to publicly funded projects. The public funds available for a pool of projects are limited and there is a backlog of critical infrastructure needs. Therefore, if any project exceeds its budget other projects are dropped from the program or the scope is reduced to provide the funds necessary to cover the cost growth. Such actions exacerbate the deterioration of a states transportation infrastructure. This study is an anthology and categorization of individual cost increase factors that were identified through an in-depth literature review. This categorization of 18 primary factors which impact the cost of all types of construction projects was verified by interviews with over 20 state highway agencies. These factors represent documented causes behind cost escalation problems. Engineers who address these escalation factors when assessing future project cost and who seek to mitigate the influence of these factors can improve the accuracy of their cost estimates and program budgetsHistorically large construction projects have been plagued by cost and schedule overruns Flyvbjerg et aL 2002. In too many cases, the final project cost has been higher than the cost estimates prepared and released during initial planning, preliminary engineering, final design, or even at the start of construction "Mega projects need more study up front to avoid cost overruns.” The ramifications of differences between early project cost estimates and bid prices or the final cost of a project can be significant. Over the time span between project initiation concept development and the completion of construction many factors may influence the final project costs. This time span is normally several years in duration but for the highly complex and technologically challenging projects it can easily exceed 10 years. Organizations face a major challenge in controlling project budgets over the time span between project initiation and the completion of construction. The development of cost estimates that accurately reflect project scope, economic conditions, and are attuned to community interest and the macroeconomic conditions provide a baseline cost that management can use to impart discipline into the design process. Projects can be delivered on budget but that requires a good starting estimate, an awareness of factors that can cause cost escalation, and project management discipline. When discipline is lacking, significant cost growth on one project can raze the larger program of projects because funds will not be available for future projects that are programmed for constructionA history of past project experiences can serve one well in understanding the challenges of delivering a quality project on budget. Repeatedly, the same problems cause project cost escalation and much wisdom can be gained by studying the past. The Holland Tunnel was, when it opened in 1927, the longest underwater tunnel ever constructed and it was also the first mechanically ventilated underwater tunnel. Its initial cost estimate was made by the renowned civil engineer George Washington Goethals. A review of the Holland Tunnel project serves to highlight the critical issues associated with estimating the costs of large complex projects and the fact that even the most distinguished engineers have trouble assessing cost drivers beyond the physical characteristics of a project. Many times there is no recognition of the cost drivers operating outside the projects physical configuration. A joint New York and New Jersey commission in 1918 recommended a transportation tunnel under the river "Urges new tunnel under the Hudson.” 1918; "Ask nation to share in tunnel to Jersey.” 1918. The automobile was emerging as the predominate means of transportation and it was decided that this tunnel should be for vehicular traffic. As a result the tunnel would employ new ventilation technologies to purge the exhaust gases produced by the internal combustion engine. Eleven designs were considered for the tunnel, most notably, one by the engineer recently responsible for finishing the Panama Canal, George Washington Goethals. He envisioned a single, bilevel tunnel with opposing traffic on each level. Goethals made a planning project cost estimate of $12 million and 3 years for construction. World War I had consumed much of the nations。