Survey of Current Practice for Design of High-Strength Concrete Prestressed Bridge Girders

A survey was conducted to determine the current state of practice for the design of high-strength concrete (HSC) prestressed bridge girders among the 52 state departments of transportation (DOTs) in the United States. A total of 41 responses were received during a 6-month period spanning from June through November 2002. It was found that the AASHTO Standard Specifications for Highway Bridges, 16th edition, is the most popular code for bridge design in current practice. In most cases its implementation is partial; most states plan complete implementation between 2003 and 2007. State DOTs have a large variation in the number of new bridges constructed, ranging from 4 to 400 bridges per year. The percentage of bridges constructed with HSC prestressed girders ranges from 0% to 100%. HSC is widely used in current practice, with 85% of the responding DOTs using specified concrete compressive strengths at service in the range of 6,000 to 8,000 psi. In this study the definition of HSC is concrete with specified compressive strengths for design of 6,000 psi or greater, made without the use of exotic materials or techniques. In some cases concrete mixture designs are governed by the specified concrete compressive strength at release. This parameter tends to be critical when it is greater than 6,000 psi. Almost half of the DOTs have some concerns related to the use of HSC, and seven DOTs have made inhouse adjustments to the design specifications for HSC prestressed bridge girders.