Factors affecting productivity of highway construction operations

The Tennessee Department of Transportation (TDOT) presently schedules highway construction projects using past experience along with some production rates obtained from historical data. Just recently TDOT has changed the way contracts are awarded. In the past TDOT awarded contracts with a working day deadline. This style of contract lead to some unreasonably long project durations. In order to alleviate this problem, TDOT has decided to change contract deadlines to a calendar date, a type of contract which requires the contractor to complete the contract on or before a given date. With the new style of contract being used, TDOT has to be extremely confident in their scheduling techniques to avoid any unnecessary claims that may result if the scheduled time is too short. To aid in the development of improved scheduling techniques, TDOT funded a research project at the University of Tennessee to investigate 22 highway construction operationsThese tasks were chosen because they make up approximately 75 percent of the time duration on typical highway construction projects.

This thesis concentrates on the factors affecting productivity of highway construction operations and presents a methodology for predicting productivity of cyclic operations which accounts for the various factors affecting productivity. Field data were collected for both cyclic and non-cyclic highway construction operations. The cyclic operations were tested using statistical analysis procedures in order to determine the most appropriate statistical model to use when predicting future production rates. The most appropriate model for use with highway construction cycle times was determined to be the lognormal distribution. After determining the most appropriate distribution, a predicted productivity rate (P₉₅) was calculated with a 95 percent confidence level.

It was found that there were several factors that affected the productivity of highway construction operations. Many of the operations were affected by more than one factor during an observationThe most often encountered factors were: delays, site conditions, resources, start-up and finishing-up operations, bunching effect, regional factors, and the amount of working days to calendar days. All of these factors are broken down further and examples are given in order to better explain how these factors affect the productivity of highway construction operations.