Title: Evaluation of a timber column bent substructure after more than 60 years in-service
Author: Wacker, James P.; Wang, Xiping; Rammer, Douglas R.; Nelson, William J.
Source: Proceedings of the CIMAD11 - 1º Congresso Ibero-LatinoAmericano da Madeira na Construção [Spanish & Latin American Conference on Timber Construction], Coimbra, Portugal, June 7-9, 2011 [electronic resource]. [S.l. : s.n.], 2011: [1 flash drive]: 7 p.
Description: This paper describes both the field evaluation and laboratory testing of two timber-column-bent bridge substructures. These substructures served as intermediate pier supports for the East Deer Park Drive Bridge located in Gaithersburg, Maryland. A field evaluation of the bridge substructure was conducted in September 2008. Nondestructive testing was performed with a moisture meter, a stress-wave timer, and a resistance micro-drilling tool. In addition, several core samples were removed for further laboratory evaluation. Live load testing of the bridge superstructure, which consists of steel girders with a glulam timber deck, was conducted concurrently using a single test vehicle. Based on subsequent load rating analysis performed on the entire bridge structural system, it was determined that the timber substructures would be replaced and were salvaged for further testing. Nondestructive tests were conducted to detect internal decay in each of the timber columns using a stress wave scanning technique. The timber-column bridge bents were then reassembled for laboratory testing. Loadings were applied at the cap beam girder locations and were based upon the test truck position which yielded the maximum support reaction forces. Additional loads are planned based on the full American Association of State Highway Transportation Officials (AASHTO) HS20-44 design load for the bridge. A comparison of the field and laboratory testing results will yield valuable information about the load response of these structural systems. The results from this work will also assist engineers more reliably assign a safe load carrying capacity to this timber bridge structural system.
Keywords: Bridges, inspection, wood deterioration, service life, design, construction, loads, moisture, maintenance, repair, weathering, nondestructive testing, micro-drilling, laminated wood, composite materials, East Deer Park Drive Bridge, laminated bridges, glulam timbers, stress-laminated bridges, timber bridges, performance testing, wooden bridges, durability, structural timbers, wood decay, moisture content
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Wacker, James P.; Wang, Xiping; Rammer, Douglas R.; Nelson, William J. 2011. Evaluation of a timber column bent substructure after more than 60 years in-service. In: Proceedings of the CIMAD11 - 1º Congresso Ibero-LatinoAmericano da Madeira na Construção [Spanish & Latin American Conference on Timber Construction,] Coimbra, Portugal, June 7-9, 2011 [electronic resource]. [S.l. : s.n.], 2011: [1 flash drive]: 7 p.
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