Construction

Prefabricated Bridge Elements and Systems Cost Study: Accelerated Bridge Construction Success Stories

Chapter 8

The contract included several incentives for early completion. If the contractor finished all work requiring Weekend or Total Bridge Closures by April 30, 2004, he would receive $100,000. In addition, for each Weekend Bridge Closure less than 4, the contractor would receive $55,000. For each Total Bridge Closure less than the number bid in the contract, the contractor would receive $4,000. For each Single Lane Closure less than the number bid in the contract, the contractor would receive $1,000.

The contract also included liquidated damages for not meeting the time constraints for accelerated construction. This included a penalty of $16,000 per Total Bridge Closure more than the number that was bid, and a penalty of $4,000 per Single Lane Closure more than the number that was bid. In addition, penalties would be assessed for any late opening of closures. A $1,700 penalty per 15-minute period would be assessed for time beyond that specified for Weekend Closure or Total Bridge Closure, and a $900 penalty per 15-minute period would be assessed for time beyond that specified for Single Lane Closure.

The engineer's estimate for this project was $ 28.8M. The low bid of $18.0M was 38% or $10.8M less than the engineer's estimate. There were 6 bidders on this project, with the 2nd lowest bid about 62% or $11.2M more than the awarded low bid.

The contractor completed all work requiring Weekend or Total Bridge Closures by the end of April 2004 and, therefore, received the $100,000 incentive. He also received an incentive of $55,000 for using 3 instead of 4 Weekend Bridge Closures, and an additional $30,000 for having 30 fewer Single Lane Closures than the 173 allowed. The contractor received a total incentive of $185,000. No liquidated damages were assessed.

3900 linear feet of deck were replaced during only 124 nights plus 3 weekend closures, with no impact to rush-hour traffic. The Washington State DOT not only obtained the new deck ahead of time with less impact to the traveling public and with increased safety, but also obtained it significantly under budget.

The details for these nine projects clearly show that prefabrication in combination with effective contracting strategies can result in the completion of bridge replacement projects on an accelerated timeline and under budget. The projects included various prefabricated bridge elements and systems that provide quality, long-lasting bridges. The projects also included bidding methods and incentives/disincentives that provided an economic reason for the contractor to innovate and to buy in to the owner's accelerated onsite construction timeline.

Prefabrication and effective contracting strategies result in cost-effective rapid bridge construction projects. Their use helps the owner accomplish its mission of efficiently moving people and goods.

Thank you for your attention.