Research Project

Evaluation of a Timber Bridge for the Secondary Road System Using FRP Reinforced Glulam Girders

Researcher(s)

Principal investigator: Terry Wipf, 515-294-9501, tjwipf@iastate.edu (project list)

Co-principal investigators:

Brent Phares, 515-294-5879, bphares@iastate.edu (project list)

Student researchers:

Jake Bigelow
Travis Hosteng

Project status

In progress

Start date: 04/01/03
End date: 03/31/07

Sponsor(s)/partner(s)

Sponsor(s):Delaware County, Iowa

About the research

Research objective: Glued laminated wood (glulam) has been used in construction for over 100 years. The development had originally been encouraged because of the lack of adequate solid timbers. Glulam can be fabricated in many shapes and sizes, and has been used significantly since 1942 for building and bridge construction, including both bridge girders and bridge decks. Glulam, like reinforced concrete, can be reinforced in the tension regions to more effectively use the compressive strength of the wood, which allows lower grade wood to be used.

Fiber reinforced polymers (FRP) have been shown to be effective in reinforcing the tension regions of glulam girders. With falling costs for the FRP material and the development of efficient manufacturing techniques, the FRP reinforced glulam has the potential to be an economically viable bridge alternative.

The proposed bridge application is to construct a single span bridge in Delaware County, Iowa, which is owned by the county. The candidate bridge has a span length of 75 ft and a width of 30 ft. The bridge will be comprised of FRP reinforced glulam girders and will use a transverse timber deck. The design will be based on recommendations and performance data supplied by the eventual manufacturer.

The Bridge Engineering Center is documenting the design, construction, and performance of this bridge. Project features include the following: comparison of design performance parameters with field measured performance and long-term evaluation of the FRP-to-timber interface integrity.

2711 S. Loop Drive, Suite 4700, Ames, Iowa 50010-8664
Phone: 515-294-9501 ~ Fax: 515-294-0467
The Bridge Engineering Center is administered by Iowa State University's Institute for Transportation.