Ground-Penetrating Radar Investigation of Salvaged Timber Girders from Bridges Along Route 66 in California


  • Xi Wu School of IoT Engineering Jiangnan University Wuxi, Jiangsu
  • Christopher Adam Senalik United States Dept. of Agriculture, Forest Service, Forest Products Laboratory
  • James P. Wacker United States Dept. of Agriculture, Forest Service, Forest Products Laboratory
  • Xiping Wang United States Dept. of Agriculture, Forest Service, Forest Products Laboratory
  • Guanghui Li School of IoT Engineering Jiangnan University Wuxi, Jiangsu


Ground penetrating radar, timber bridge, steel nail, hole, decay, split


This study describes assessment of the internal conditions of timber bridge structural members along Route 66 in California. These timber bridges were exposed to desert climate conditions for several decades, which can lead to a variety of deterioration. Overtime, the deterioration may cause loss of structural integrity within the bridges and lead to potentially hazardous conditions for the motoring public. Members from dismantled bridges were brought to the Forest Products Laboratory in Madison, WI. Strength-reducing features including decay, splits and cracks insect attack, and corrosion of metal components were initially identified using visual inspection. Further assessment was then performed using several nondestructive testing technologies including ground=penetrating radar (GPR). GPR was used, among other nondestructive techniques, to identify and locate internal features and defects within the timbers. The tomographic output of the GPR known as radargrams, revealed deterioration. Based on the information contained within the radargrams, it was possible to classify some internal features and defects with a high degree of certainty, whereas others remained less clear. In this study, the potential of using GPR for inspection of bridge timbers is discussed and supported through interpretation of the radargrams.


Aguwa JI (2014) Structural performance of the Nigerian grown Abura timber bridge beam subjected to compression and shearing forces. KSCE J Civ Eng 19(4):974-981.

Alsharqawi M, Zayed T, Dabous SA (2018) Integrated condition rating and forecasting method for bridge decks using visual inspection and ground penetrating radar. Autom Construct 89:135-145.

Asadi P, Gindy M, Alvarez M (2019) A machine learning based approach for automatic rebar detection and quantification of deterioration in concrete bridge deck ground penetrating radar B-scan images. KSCE J Civ Eng 23(6): 2618-2627.

Benson AK (1995) Applications of ground penetrating radar in assessing some geological hazards: Examples of groundwater contamination, faults, cavities. J Appl Geophys 33:177-193.

Butnor JR, Doolittle JA, Johnsen KH, Samuelson L, Stokes T, Kress L (2003) Utility of ground-penetrating radar as a root biomass survey tool in forest systems. Soil Sci Soc Am J 67(5):1607.

Cardimona S, Willeford B, Wenzlick J, Anderson N (2000) Investigation of bridge decks utilizing ground penetrating radar. In International Conference on the Application of Geophysical Technologies to Planning, Design, Construction, and Maintenance of Transportation Facilities, December 11-15, 2000, St. Louis, MO.

Colla C (2010) GPR of a timber structural element. Pages 1-5 in Proc. XIII International Conference on Ground Penetrating Radar, IEEE, Lecce, Italy.

Dinh K, Gucunski N, Duong TH (2018) An algorithm for automatic localization and detection of rebars from GPR data of concrete bridge decks. Autom Construct 89:292-298.

Geophysical Survey Systems, Inc (2014) SIR 4000 manual. Geophysical Survey Systems, Inc., Nashua, NH. .

Halabe UB, Agrawal S, Gopalakrishnan B (2009) Nondestructive evaluation of wooden logs using ground penetrating radar. Nondestruct Test Eval 24(4):329-346.

Hans G, Redman D, Leblon B, Nader J, Larocque A (2015) Determination of log moisture content using ground penetrating radar (GPR). Part 2. Propagation velocity (PV) method. Holzforschung 69(9):1125-1132.

Harkat H, Ruano AE, Ruano MG, Bennani SD (2019) GPR target detection using a neural network classifier designed by a multi-objective genetic algorithm. Appl Soft Comput 79:310-325.

Hogan G (1999) Migration of ground penetrating radar data: A technique for locating subsurface targets. SEG Tech Prog Exp Abstr 7(1):1359.

Lorenzo H, Perezgracia V, Novo A, Armesto J (2010) Forestry applications of ground-penetrating radar. For Syst 19(1):5-17.

Maı T, Sbartaı Z, Bos F, Razafindratsima S, Demontoux F (2014) Non-destructive evaluation of timber structures using GPR technique. Pages 218-222 in 15th International Conference on Ground Penetrating Radar, IEEE, Brussels, Belgium, June 30-July 4, 2014.

Martınez-Sala R, Rodrıguez-Abad I, Diez Barra R, Capuz-Lladro R (2013) Assessment of the dielectric anisotropy in timber using the nondestructive GPR technique. Constr Build Mater 38:903-911.

Muller W (2002) Trial of ground penetrating radar to locate defects in timber bridge girders. In State Conference, Institute of Public Works Engineering Australia (IPWEA) Queensland Division, Noosa Lakes Convention Centre, October 6-10, 2002, Queensland, Australia.

Neal A (2004) Ground-penetrating radar and its use in sedimentology: Principles, problems and progress. Earth Sci Rev 66(3-4):261-330.

Novo A, Solla M, Montero-Fenollos JL, Lorenzo H (2014) Searching for the remains of an Early Bronze Age city at Tell Qubr Abu al-‘Atiq (Syria) through archaeological investigations and GPR imaging. J Cult Herit 15:575-579.

Nuñez-Nieto X, Solla M, Novo A, Lorenzo H (2014) Three-dimensional ground-penetrating radar methodologies for the characterization and volumetric reconstruction of underground tunneling. Constr Build Mater 71:551-560.

Pyakurel S (2009) Two-dimensional and three-dimensional GPR imaging of wood and fiber reinforced polymer composites. PhD dissertation in Civil and Environmental Engineering, West Virginia University, Morgantown, WV.

Reci H, Maı TC, Sbartaı ZM, Pajewski L, Kiri E (2016) Nondestructive evaluation of moisture content in wood using ground-penetrating radar. Geosci Instrum 5(2):1-12.

Riggio M, Anthony RW, Augelli F, Kasal B, Lechner T, Muller W, Tannert T (2014) In situ assessment of structural timber using non-destructive techniques. Mater Struct 47(5):747-766.

Rodrıguez-Abad I, Martınez-Sala R, Capuz R, Dıez R, Garcıa F (2011a) Assessment of the variation of the moisture content in the Pinus pinaster Ait. using the non destructive GPR technique. Mater Constr 61(301):143-156.

Rodrıguez-Abad I, Martınez-Sala R, Garcıa F, Capuz-Lladro R, Dıez R (2011b) Non-destructive characterization of maritime pine sawn timber dielectric anisotropy by means of GPR. Pages 1-5 in 2011 6th International Workshop on Advanced Ground Penetrating Radar (IWAGPR), June 22-24, 2011, Aachen, Germany.

Wacker J, Mikhail M, Dizon G (2017) Evaluation of bridge components salvaged from historic Route 66 in California. Research in Progress RIP-4719-038. USDA Forest Service, Forest Products Laboratory, Madison, WI.

Yao Q, Wang QF (2012) Kirchoff migration algorithm for ground penetrating radar data. Pages 396-398 in International Conference on Computer Science & Electronics Engineering, IEEE, March 23-25, 2012, Hangzhou, China.





Research Contributions