Coordination needs and supply of subway projects

Coordination has been regarded as a critical factor of construction projects, but it is usually not well understood. It is common that time and money are spent on coordination yet the performance is not as expected. This paper studies the coordination needs and supply of construction projects. First, coordination needs were derived from work uncertainty and equivocality (U and E), and supply was offered by different methods engineers use to coordinate. Then ten subway construction projects were investigated. A questionnaire was modified to quantify the project U and E, and a time sheet designed to collect contractor engineers' work time allocated in nine coordination methods. Finally, how actual coordination time distribution meets the needs and their relationships with performance were analyzed. The results indicate that the project performance is not related to the level of U and E. In the nine coordination methods of the studied projects, site visit takes up most time (23%), followed by correspondence (20.5%) and meetings (13%). Projects with good performance apply adequate oral or written coordination mainly based on work equivocality.