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Project Details
STATUS

Completed

START DATE

12/31/11

END DATE

07/31/19

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC, NCWTS
SPONSORS

USDA Forest Products Laboratory

Researchers
Principal Investigator
Brent Phares

Bridge Research Engineer, BEC

Co-Principal Investigator
Travis Hosteng

Co-Director, NCWTS

About the research

Nationwide, bridges are deteriorating at a rate faster than they can be rehabilitated and maintained. This has resulted in a search for new methods to rehabilitate, repair, manage, and construct bridges. As a result, structural health monitoring and smart structure concepts have emerged to help improve bridge management. In the case of timber bridges, however, a limited amount of research as been conducted on long-term structural health monitoring solutions, and this is especially true in regards to historic covered timber bridges. To date, evaluation efforts of timber bridges have focused primarily on visual inspection data to determine the structural integrity of timber structures.

To fill this research need and help improve timber bridge inspection and management strategies, a 5-year research plan to develop a smart timber bridge structure was undertaken. The overall goal of the 5-year plan was to develop a turnkey system to analyze, monitor, and report on the performance and condition of timber bridges. This report outlines one phase of the 5-year research plan and focuses on developing and attaching moisture sensors onto timber bridge components. The goal was to investigate the potential for sensor technologies to reliably monitor the in situ moisture content of the timber members in historic covered bridges, especially those recently rehabilitated with glulam materials. The timber-specific moisture sensors detailed in this report and the data collected from them will assist in advancing the smart timber bridge.

Project Details
STATUS

In-Progress

START DATE

06/15/18

END DATE

06/30/20

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, NCWTS
SPONSORS

USDA Forest Products Laboratory

Researchers
Principal Investigator
Travis Hosteng

Co-Director, NCWTS

About the research

Project Details
STATUS

In-Progress

START DATE

07/01/16

END DATE

06/30/17

RESEARCH CENTERS NCWTS
SPONSORS

Michigan Technological University
USDA Forest Products Laboratory

Researchers
Principal Investigator
Mark Rudnicki

Michigan Technological University

Principal Investigator
Robert J. Ross

USDA Forest Services, Forest Products Laboratory

About the research

Wood is highly variable because of genetic variation and variable growing environments. To make the best, highest use of our forest resources, we need to have technologies that help us assess the quality of a particu- lar tree, log, or primary product. We can then use it for its best use—nondestructive evaluation technologies enable us to characterize important properties of wood, allowing us to use it appropriately. The USDA Forest Service Forest Products Laboratory, in cooperation with organizations from around the world, develops nondestructive evaluation technologies as part of itsprogram to find the best uses for our timber resources.

The objective of this program is to develop nondestructive evaluation technologies for a range of forest materials and products, with a focus on developing technologies for assessing woody biomass from our Eastern forests.

Project Details
STATUS

Completed

PROJECT NUMBER

2012-05

START DATE

01/01/14

END DATE

07/31/14

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, Aurora
SPONSORS

USDA Forest Products Laboratory

Researchers

About the research

In seasonal frost areas, some state departments of transportation (DOTs) take advantage of the period of higher strength in midwinter by using winter weight premiums (WWPs) to increase the allowable weight that trucks can haul. Conversely, to reduce damage during the spring thaw, many road management agencies apply spring load restrictions (SLRs). The objective of this effort was to provide an understanding of the reliability, benefits, costs, and risks of alternate approaches to scheduling seasonal load restrictions on roadways.

Project Details
STATUS

In-Progress

START DATE

05/22/15

END DATE

01/31/19

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC, NCWTS
SPONSORS

USDA Forest Products Laboratory

Researchers
Principal Investigator
Travis Hosteng

Co-Director, NCWTS

About the research

Investigation of Glulam Girder Bridges with Composite Prefabricated Decks

Project Details
STATUS

In-Progress

START DATE

07/14/14

END DATE

06/30/17

RESEARCH CENTERS InTrans, BEC, CTRE
SPONSORS

USDA Forest Products Laboratory

Researchers
Principal Investigator
Travis Hosteng

Co-Director, NCWTS

Co-Principal Investigator
Brent Phares

Bridge Research Engineer, BEC

About the research

The purpose of this project is to develop techniques that were developed in Phase I to a broader set of covered bridge types that include but are not limited to a town lattice configuration and provide recommendations for improving the analysis of historic covered timber bridges, specifically the intersection and interconnection of lattice members, impact of classic arch behavior, and behavior and interaction of bolster beams and floor systems.
Project Details
STATUS

In-Progress

START DATE

04/26/13

END DATE

06/30/17

RESEARCH CENTERS InTrans, BEC, CTRE
SPONSORS

USDA Forest Products Laboratory

Researchers
Principal Investigator
Travis Hosteng

Co-Director, NCWTS

Co-Principal Investigator
Brent Phares

Bridge Research Engineer, BEC

Co-Principal Investigator
James Wacker

Co-Director, NCWTS

About the research

Background

Most engineering analyses of historic covered timber bridge trusses are based solely on routine site inspections. In addition, assumptions about the behavior of connections and support conditions are made during the systemic analysis stage. This approach can lead to inaccurate and, in most cases, overly conservative load-capacity ratings for these historic structures.

By conducting live-load testing to assess the overall performance of the superstructure system, engineers will be able to perform structural analyses in a more reliable fashion. The measured live load response should also provide a measure of the effectiveness of various structure modeling techniques. The end result should be a more reliable approach to assigning safe load-capacity ratings for historic covered bridges.

During Phase I of this project, 11 covered bridges were evaluated by live-load testing methods: three covered bridges in Parke County, Indiana, built of variations of the Burr-Arch truss configuration; four other covered bridges in Indiana built of variations of the Howe truss configuration; and four covered bridges in Vermont built of variations of the Queen post truss configuration.

Objective

This study will continue the work initiated in Phase I to develop and establish recommended procedures for safely and reliably load-rating historic covered bridges through physical testing.

Approach

  • Develop field protocols for live-load testing of his­toric covered bridges, in conjunction with analytical modeling data requirements
  • Conduct live-load testing on several bridges repre­senting the main truss types that have been preserved
  • Analyze load-testing field data and disseminate data to analytical modeling efforts
  • Develop a rationale for incorporating physical test data into existing load-rating procedures
  • Prepare a comprehensive guidance manual that documents recommended procedures for live-load testing and enhanced load rating of historic covered bridges
Project Details
STATUS

In-Progress

START DATE

06/27/12

END DATE

06/15/17

RESEARCH CENTERS InTrans, BEC, CTRE, NCWTS
SPONSORS

USDA Forest Products Laboratory

Researchers
Principal Investigator
Travis Hosteng

Co-Director, NCWTS

Co-Principal Investigator
Brent Phares

Bridge Research Engineer, BEC

Co-Principal Investigator
Simon Laflamme

About the research

The purpose of the project is to develop automated techniques for determining vehicle characteristics as they cross the smart timber bridge. By determining vehicle characteristics–such as vehicle weight, axle weights, axle spacings, travel lane, speed, and so forth–it will be possible to enhance other algorithms for predicting usage and induced damage or deterioration.

Two different vehicle characterization approaches will be investigated:

  • Use of conventional instrumentation
  • Use of non-conventional instrumentation including the sensing skin
Project Details
STATUS

Completed

START DATE

08/15/07

END DATE

12/31/12

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC, CTRE, NCWTS
SPONSORS

USDA Forest Products Laboratory

Researchers
Principal Investigator
Terry Wipf

Faculty Affiliate

Co-Principal Investigator
Travis Hosteng

Co-Director, NCWTS

Co-Principal Investigator
Brent Phares

Bridge Research Engineer, BEC

About the research

The objective of the second phase of this project was to conduct full-scale field evaluations of various methods identified in previous research related to differential panel deflection and wearing surface distress in transverse glulam deck panels supported by longitudinal glulam stringers. The purpose of the Phase III study was to determine localized structural performance of the previously constructed demonstration bridge in Delaware County, Iowa to determine the cause of asphalt overlay cracking, assess the appropriateness of the existing asphalt overlay mix, and formulate a new asphalt mix design that performs better on transverse glulam decks.

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