BIM: Historical Covered Bridge-4/10

Use of Laser Scanning Technology to Obtain As-Built Records of Historic Covered Bridges

Introduction

Documentation of covered timber bridges allows America to preserve the history of their life as many are being lost forever. New laser scanning techniques will be used by a cooperative Forest Service and University of Minnesota Duluth research team to document several of these bridges in a rapid, accurate and cost-effective approach. An implementation approach will be developed for using laser scanning for historic covered wood bridges.

Background

Covered bridges have been the fabric of American life. Today there are several hundred historic covered bridges remaining. Although there is much effort to preserve these structures, oftentimes high cost of restoration, neglect and vandalism takes its toll, and many are lost forever. One of the more famous bridges from "Bridges of Madison County movie" fame was burned down last year. As we cannot completely prevent these types of incidents from occurring, we at least should properly document these bridges for posterity. The National Park Service's Historic American Engineering Record (HAER) has efforts underway to document historic structures. Their Level I documentation is defined in the Secretary of the Interior's Standards and Guidelines for Architectural and Engineering Documentation, and consists of measured and interpretive drawings, large-format photographs, and written historical reports. In order to assist in this effort newer technologies need to be explored which can provide as built records at a faster rate and with more accuracy. This research will explore the use of laser scanning technology to scan existing bridges for purposes of obtaining as-built records. Priority will be given to any bridge in danger of collapse or removal. Level I documentation standards will be followed to develop records. This research will lead to the identification and demonstration of laser scanning technology and the development of Level I documentation using this technology.

Zumbrota Bridge During a Flood

Objective

This project will examine the technical feasibility of using laser scanning technologies for obtaining as-built records for historic, covered timber bridges.

Research Methods

1. Review technical literature pertaining to laser scanning technologies (completed)
2. Establish access to laser scanning equipment;
3. Identify six historic covered timber bridges for evaluation;
4. Conduct field tests with scanning equipment on identified bridges;
5. Perform field measurements on identified bridges;
6. Compare/contrast laser scanning equipment results with field measurements;
7. Prepare final report.

Expected Outputs

1. Technology demonstration at USDA Forest Products Laboratory, June 23, 2010 as part of FPL Centennial Celebration (Madison, WI)
2. Final technical report.
3. Final powerpoint presentation.

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