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Development of a Smart Timber Bridge (Phase III): Moisture and Strain Sensor Investigation for Historic Covered Bridges

https://research.thinkwood.com/en/permalink/catalogue2182
Year of Publication
2019
Topic
Moisture
Material
Glulam (Glue-Laminated Timber)
Other Materials
Application
Bridges and Spans
Author
Phares, Brent
Pence, Trevor
Wacker, James
Hosteng, Travis
Year of Publication
2019
Country of Publication
United States
Format
Report
Material
Glulam (Glue-Laminated Timber)
Other Materials
Application
Bridges and Spans
Topic
Moisture
Keywords
Moisture Content
Sensor
Strain
Reliability
Accuracy
Language
English
Research Status
Complete
Series
General Technical Report
Summary
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.
Online Access
Free
Resource Link
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Durable Timber Bridges - Final Report and Guidelines

https://research.thinkwood.com/en/permalink/catalogue2133
Year of Publication
2017
Topic
Design and Systems
Moisture
Serviceability
Material
Timber (unspecified)
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans

Effect of Moisture Induced Stresses on the Mechanical Performance of Glulam Beams of Vihantasalmi Bridge

https://research.thinkwood.com/en/permalink/catalogue1609
Year of Publication
2016
Topic
Moisture
Serviceability
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Author
Hradil, Petr
Fortino, Stefania
Salokangas, Lauri
Musci, Alessandro
Metelli, Giovanni
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Bridges and Spans
Topic
Moisture
Serviceability
Keywords
Moisture Induced Stresses
Finland
Moisture Gradients
Moisture Content
Hygrothermal
Multi-Fickian Theory
Relative Humidity
Temperature
Eurocode 5
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2159-2167
Summary
The present paper deals with the effect of moisture induced stresses (MIS) on the mechanical performance of a glulam beam of Vihantasalmi Bridge in Finland. MIS caused by high moisture gradients in a cross section of the glulam beam are calculated by a hygro-thermal multi-Fickian model for evaluation of moisture content, relative humidity and temperature in wood that is...
Online Access
Free
Resource Link
Less detail

Identifying Incipient Decay in Douglas-fir Bridge Components using X-Ray Computerized Tomography

https://research.thinkwood.com/en/permalink/catalogue2350
Year of Publication
2019
Topic
Design and Systems
Moisture
Serviceability
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Application
Bridges and Spans
Author
Senalik, Christopher
Wacker, James
Wang, Xiping
Wu, Xi
Year of Publication
2019
Country of Publication
United States
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Application
Bridges and Spans
Topic
Design and Systems
Moisture
Serviceability
Keywords
X-ray Computerized Tomography
Wood Timber
Brown Rot Fungus
Incipient Decay
Language
English
Conference
International Nondestructive Testing and Evaluation of Wood Symposium
Research Status
Complete
Summary
In this report, wooden members of sizes typically used in bridge construction are examined using x-ray computerized tomography (CT) to determine the presence of internal decay. This report is part of an overall study in which Douglas-fir (Pseudotsuga menziesii) glue-laminated (glulam) beams and solid sawn timbers were inoculated with brown rot fungus, Fomitopsis pinicola, and exposed to aboveground conditions approximately 25 miles (40 km) north of Gulfport, Mississippi, USA. The goal of the overall study is to develop interior decay within the test specimens and then identify and characterize the decay using a variety of nondestructive testing (NDT) techniques. One NDT technique used is x-ray CT. The pixel brightness (PB) of CT scan images is proportional to the specific gravity (SG) at that location; high SG materials appear brighter whereas low SG materials appear darker. The consumption of wood by fungus decreases the wood SG; however, fungal progression takes place in areas where sufficient moisture is present. The presence of moisture increases wood SG as detected by the CT scan, which masks the effect of the fungal decay, which is a common co-occurrence with many NDT techniques. To identify incipient decay, it is necessary to examine the ring structure both within and outside of the area of moisture. Quantifying the extent of the decay requires correlating the PB to known SG values for both dry wood and wood of varying moisture content. In this report, the relationship between wood SG, moisture content, and PB was quantified.
Online Access
Free
Resource Link
Less detail

Moisture-Induced Stresses in Large Glulam Beams. Case Study: Vihantasalmi Bridge

https://research.thinkwood.com/en/permalink/catalogue2468
Year of Publication
2019
Topic
Moisture
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Bridges and Spans