Predicting cost overrun of railroad bridge construction

Railroad Bridge Construction Projects have frequently exceeded their cost and schedule resulting in major financial losses to the owners and to the contractors, severe interruption of the rail operation schedules and consequently significant inconvenience to the rail commuters. Currently, there are very few methods available to predict the completed construction cost. This research proposes cost estimating model that incorporates the “major uncertainty constraints” (MUC) which drive both the cost and schedule of Railroad bridge Construction. This approach is an advanced unique model that is proposed for calculation of adequate contingency in a portfolio of construction projects. It is used to update historical contingency values based on new railroad project data that becomes available as soon as construction projects are completed. A comprehensive literature search reveals that many researchers have developed models to predict cost overruns by considering only change orders as the main driver of construction cost overrun without considering the MUC impact. Owners and managers, who are in charge of estimating budget and construction duration in both public and private sectors, have limitations in predicting such tasks accurately. Data on completed projects are obtained from one of the nation largest Transit agency for 70 Railroad bridge construction projects. It examines the challenging environment of Railroad Bridge Construction Industry and describes the development of a predictive model of cost deviation in such high-risk projects. Based on an in-depth evaluation and analysis of completed railroad bridge construction projects, historical data was obtained on reasons behind cost overrun and underrun from 25 Railroad bridge projects which experienced cost overrun and underrun as study cases out of 70 completed general Railroad construction projects. This study contributes to a uniquely better understanding of the reasons for cost deviation in Railroad bridge construction projects and provides a decision support tool to quantify the extend of that deviation. Its results are expected to support the bridge owners and contractors who are in charge of estimating budget and construction duration in Railroad Bridge Construction sectors in accurately predicting the construction cost based on adequately calculated cost contingency at the business planning or early stage of a project.Ph.D.Includes bibliographical referencesby Medhat George Attar