PMSS Project Details

Project ID:	FHWA-PROJ-08-0047
Project Name:	Evaluating Naturally Durable Wood Species for Repair and Rehabilitation of Above Ground Components in Covered Bridges
Status:	Active
Contact:	Last Name: Duwadi First Name: Sheila R Telephone: 202-493-3106 E-mail: sheila.duwadi@dot.gov
Organization:	Federal Highway Administration - Turner-Fairbank Highway Research Center (TFHRC)
Office:	Office of Infrastructure Research and Development
Team:	Hazard Mitigation Team
Roadmap/Focus area(s):	Historic Preservation Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:	Covered bridges are designed for protection from the elements, but it is difficult to protect all wood components from moisture exposure. Some areas of the structures, such as weatherboarding and wood members near the ends of the bridges, are particularly susceptible to wind-driven precipitation. Consequently, biodeterioration from decay and insects is frequently responsible for replacement of aboveground covered bridge components. Naturally durable domestic wood species, particularly underutilized or invasive species, should provide a suitable alternative to chemically treated wood products for repair and replacement of aboveground components of covered bridges. Chemical extractives have long been recognized as key features that impart natural durability in the heartwood of certain wood species. The extractives themselves have been evaluated for use as environmentally friendly preservatives or additives to coatings, but little is known about the chemical makeup of the extractives. Research is needed to isolate, identify, and characterize the chemical extractivesbelieved to be responsible for high resistance to decay and insects in well-known and lesser-known durable domestic wood species. A comparison of chemical properties of well-known and lesser-known wood species will improve our understanding of the differences in physical properties and offer opportunities as suitable materials for repair and rehabilitation of covered bridge components in protected outdoor exposure. The chemical component(s) responsible for imparting durability could also provide new environmentally benign wood protection systems for above ground components of covered bridges.
Laboratories:	Not Applicable
Start Date:	October 1, 2008
End Date:	September 30, 2013
Funding Amount:	$131,717.00
FHWA Program Name:	National Historic Covered Bridge Preservation Program
Goals:	The objective is to identify and characterize durable wood species resistant to decay and insects.
Project Type:	Offsite
Background Information:	Data not yet available
Test Methodology:	This study will include analytical and experimental work both in the lab and in the field.
Other Information:	Funding is $131,717 from the Federal Highway Administration plus $30,000 from the Forest Service, Forest Products Laboratory.
Partners:	Data not yet available
More Information URL(s):
Fieldtest:	Data not yet available
Expected Benefits:	The expected benefit is the identification of durable wood species that owners can use in building new and/or rehabilitating timber structures.
Deliverables:	Name: Manual with recommendations for use and application of naturally durable wood species as replacement components and/or for new uses. (9/2013) Product Type(s): Research report, Techbrief Description: Manual with recommendations for use and application of naturally durable wood species as replacement components and/or for new uses. Audiences: Researchers, State highway agencies Secondary Audiences:
Related URL(s):
Project Findings:	Data not yet available
FHWA Topics:	Roads and Bridges--Structures
TRT Terms:	Covered Bridges Wooden Bridges Infrastructure Bridges Wood Rehabilitation (Maintenance) Biodeterioration Research
FHWA Disciplines:	Environment Structures
Subject Areas:	Bridges and other structures Research