Comparison of design-build and design-bid-build performance of public university projects.

摘要

With an unsure market and scarce work, owners across the United States, especially universities, are finding themselves in situations where they are unable to complete their projects within cost and schedule using the traditional delivery method: Design--Bid--Build (DBB). Under the DBB project delivery method, many competent contractors are electing to send low bids on projects just to keep work on their books, with plans to receive change orders once the project is underway; this practice is leading to cost and schedule overruns. Public universities across the United States are beginning to elect to use Design-Build (DB) as an alternate project delivery method over the traditional project delivery method of DBB in order to aid in reducing the cost, schedule, and change orders.;Due to current legislation in effect, all 50 states are able to use the DB delivery method. However, only 20 states and their public agencies are permitted to use DB for all types of design and construction projects. In 18 states, DB is widely permitted, but not all agencies are permitted to use this delivery method. In the remaining 12 states, DB is a limited option.;In order to analyze and compare Design-Build (DB) and Design-Bid-Build (DBB) projects, this study collected data, by means of convenient random sampling, from construction projects built by Planning and Construction Departments of U.S. universities. Statistical tests were conducted to determine if the metrics related to cost, schedule, and change orders were significantly different from each other in these two types of projects.;The findings of this study will help public universities decide what delivery method is best for them in terms of controlling costs, schedule, and change orders. The results showed that DB projects significantly outperformed DBB projects in terms of Contract Award Cost Growth, Design and Construction Schedule Growth, Total Schedule Growth, Construction Intensity, Construction Change Order Cost Growth, and Total Change Order Cost Growth.