Table Of ContentIn Situ Assessment of Structural Timber
RILEM STATE OF THE ART REPORTS
Volume7
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Bohumil Kasal Thomas Tannert
Editors
In Situ Assessment of
Structural Timber
State of the Art Report of the RILEM
Technical Committee 215-AST
ABC
Editors
BohumilKasal ThomasTannert
FraunhoferInstituteforWoodResearch BerneUniversityofAppliedSciences
Wilhelm-Klauditz-InstitutWKI TimberandCompositeConstruction
BienroderWeg54E Solothurnstrasse102
38108Braunschweig 2500Biel
Germany Switzerland
E-mail:[email protected] E-mail:[email protected]
ISBN978-94-007-0559-3 e-ISBN978-94-007-0560-9
DOI10.1007/978-94-007-0560-9
SpringerDordrechtHeidelbergLondonNewYork
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Contents
State-of-the-ArtReport .......................................... ix
Preface ........................................................ xi
ListofSymbolsandAbbreviations................................. xiii
ListofFigures ..................................................... xv
ListofTables ...................................................... xix
Introduction.................................................... 1
References..................................................... 3
1 StressWaves ............................................... 5
BohumilKasal,GretchenLear,andThomasTannert
1.1 Background.............................................. 5
1.2 Equipment............................................... 7
1.2.1 Sounding ........................................ 7
1.2.2 SonicStressWaves ................................ 7
1.2.3 UltrasonicTechnique .............................. 10
1.2.4 UltrasonicEchoTechnique ......................... 11
1.3 Application .............................................. 14
1.3.1 DefectandDeteriorationDetection................... 14
1.3.2 MechanicalProperties.............................. 18
1.4 Limitations .............................................. 19
1.4.1 DeteriorationandDecayDetection................... 21
1.4.2 MechanicalPropertyPrediction...................... 21
References..................................................... 22
v
vi Contents
2 GroundPenetratingRadar ................................... 25
MehdiSbartaï
2.1 Background.............................................. 25
2.1.1 DielectricPermittivityofWood...................... 27
2.2 Equipment............................................... 29
2.3 Applications ............................................. 32
2.3.1 Detection ........................................ 33
2.3.2 MoistureEvaluation ............................... 34
2.4 Limitations .............................................. 35
References..................................................... 36
3 Radiography ............................................... 39
BohumilKasal,GretchenLearandRonAnthony
3.1 Background.............................................. 39
3.2 Equipment............................................... 40
3.2.1 Technology....................................... 40
3.2.2 GammaRays ..................................... 41
3.2.3 X-Rays .......................................... 41
3.2.4 RadiationAttenuation.............................. 42
3.2.5 Imaging ......................................... 44
3.3 Application .............................................. 47
3.4 Limitations .............................................. 48
References..................................................... 49
4 ResistanceDrilling .......................................... 51
GretchenLear,BohumilKasalandRonAnthony
4.1 Background.............................................. 51
4.2 Equipment............................................... 52
4.3 Application .............................................. 53
4.4 Limitations .............................................. 56
References..................................................... 57
5 Core-Drilling............................................... 59
BohumilKasal
5.1 Background.............................................. 59
5.2 Equipment............................................... 60
5.3 Application .............................................. 61
5.4 Limitations .............................................. 64
References..................................................... 65
6 ShearTestofGlueLines ..................................... 67
ThomasTannert
6.1 Background.............................................. 67
6.2 Equipment............................................... 67
6.3 Application .............................................. 69
6.3.1 DeterminationofPercentageWoodFailure ............ 70
Contents vii
6.4 Limitations .............................................. 70
References..................................................... 72
7 TensionMicro-Specimens .................................... 75
BohumilKasal
7.1 Background.............................................. 75
7.2 Equipment............................................... 76
7.3 Application .............................................. 77
7.4 Limitations .............................................. 78
References..................................................... 80
8 ScrewResistance ........................................... 81
NobuyoshiYamaguchi
8.1 Background.............................................. 81
8.2 Equipment............................................... 82
8.3 Application .............................................. 82
8.3.1 StrengthEstimatefromScrewWithdrawalTest......... 82
8.3.2 Strength Estimate from Screw Withdrawals and
VelocityofStressWave ............................ 83
8.3.3 ScrewWithdrawalsandAnglesofEntry .............. 83
8.3.4 ScrewWithdrawalsandCompressionCapacity......... 83
8.3.5 DensitiesfromScrewWithdrawals ................... 84
8.3.6 Stiffness Estimate from Screw Withdrawalsand
VelocityofStressWave ............................ 85
8.3.7 Summary ........................................ 85
8.4 Limitations .............................................. 85
References..................................................... 86
9 HardnessTest .............................................. 87
MariapaolaRiggioandMaurizioPiazza
9.1 Background.............................................. 87
9.2 EquipmentandApplication................................. 88
9.2.1 JankaHardnessTest ............................... 89
References..................................................... 96
10 MoistureMeasurement ...................................... 99
BohumilKasalandGretchenLear
10.1 Background.............................................. 99
10.2 Equipment...............................................100
10.2.1 PinMeters .......................................100
10.2.2 Pin-lessMeters ...................................101
10.3 Application ..............................................102
10.4 Limitations ..............................................103
References.....................................................103
viii Contents
11 SpeciesIdentification ........................................ 105
NicolaMacchioni
11.1 Equipment...............................................105
11.1.1 MacroscopicEvaluation............................106
11.1.2 MicroscopicEvaluations ...........................106
11.2 Application ..............................................107
11.3 Limitations ..............................................107
References.....................................................107
12 Dendrochronology .......................................... 109
OliviaPignatelli
12.1 Background..............................................109
12.2 Equipment...............................................110
12.3 Application ..............................................111
12.3.1 WoodSpeciesIdentification.........................111
12.4 Limitations ..............................................112
References.....................................................114
13 ReviewofCodesandStandards ............................... 115
NicolaMacchioni,ClaraBertoliniandThomasTannert
13.1 CodesandStandards ......................................115
13.1.1 InternationalStandards.............................115
13.1.2 NationalStandards ................................116
13.2 DescriptionoftheExistingConditions .......................118
13.2.1 DiagnosisoftheStructuralElements .................118
13.2.2 ObjectivesoftheInspection.........................119
13.2.3 InspectionProcedure...............................119
13.2.4 InspectionReport .................................120
References.....................................................120
KeyWordsIndex...................................................123
State-of-the-Art Report
ThisreportispartlybasedontheMSthesisofGretchenLearentitled“Improvingthe
AssessmentofInSituTimberMemberswiththeUseofNondestructiveandSemi-
DestructiveTestingTechniques”(underthedirectionofBohumilKasal)submitted
totheDepartmentofCivilEngineeringofNorthCarolinaStateUniversity,Raleigh,
NC,inDecember2005.
ContributingTCAST-215membersare:RonaldAnthony,WoodScientist, Fort
Collins, USA; Professor Clara Bertolini Cestari, Politecnico di Torino, Italy; Dr.
Milos Drdacky, Institute of Theoretical and Applied Mechanics, Prague, Czech
Republic; Professor Bohumil Kasal, Penn State University, USA; Dr. Nicola
Macchioni, Istituto per la Valorizzazionedel Legno e delle Specie Arboree, Italy;
Professor Maurizio Piazza, Università degli Studi di Trento, Italy; Dr. Olivia
Pignatelli,Dendrodatas.a.s,Italy;Dr.MariapaolaRiggio,UniversitàdegliStudidi
Trento,Italy;Dr.MehdiSbartaï,UniversitéBordeaux,France;Dr.ThomasTannert,
Bern University of Applied Sciences, Switzerland; Dr. Nobuyoshi Yamaguchi,
BuildingResearchInstitute,Tsukuba,Japan.
Dr. Thomas Tannert provided vital help during the final phases of the review.
HelpofRonaldAnthonywiththemanuscriptsisgreatlyappreciated.
RILEMTC215-AST
BohumilKasalandThomasTannert
Editors
ix
Preface
Woodisoneofthemostintriguingstructuralmaterialsandtheonlyonethatistruly
renewable.Alongwithstone,woodistheoldeststructuralmaterialontheplanetand
hasbeenextensivelyusedthroughoutthehumanhistory.Duetoitsaestheticalvalue
andpositiveenvironmentalimpact,woodhasexperiencedrenaissanceinconstruc-
tion. As a biodegradable, hygroscopic, non-isotropic material, the wood presents
specialchallengesforaprofessionalandrequiresthroughknowledgerangingfrom
biologytocontinuummechanics.
This state-of-the-art report reflects the current knowledge in the area of in
situ assessment of the physical and mechanical properties of wood structures.
Nondestructive, semi-destructive and destructive methods are described in a sys-
tematic mannerwheretechnology,equipmentandlimitationsarediscussed. Some
ofthediscussedmethodsareusedinothermaterialssuchasmasonryandconcrete.
Most of the methods, however,are specific to wood and special qualificationsare
required to understand and apply these methods effectively. Existing methods are
constantly improved and new methods are being developed. This report includes
methods that are used in practice or have shown significant promise and have a
bodyofknowledgethatsupportsstatementsmadeinthisreport.
Tocontinuetoimprovetheassessmentofinsitutimbermembers,moreresearch
is required to both estimate individual member strengths as well as obtain accur-
atequantificationofdeterioration.Afterextensiveresearchofstresswaveinvestig-
ative techniques for timber members, the conclusion was drawn that the relation-
shipbetweenstresswaveparametersandtimbermechanicalpropertieswasnotde-
veloped enough to accurately predict in situ member strength. Published research
andassociatedcorrelationvalueswereinconsistentandattimesconflictingdepend-
ingontechnique,speciesandstresswaveparametersemployed.Researchopportun-
itieslieinfindingamethodofapplyingstresswavetechniquestoinsitumembers
andarrivingatreliableestimatesofthemember’sstrength.
Improvementofthetensiletechniquecouldalsobeaddressed.Correctingequip-
mentdetailsaswellasaddressingsamplesizeforgraininclusionandimprovements
tothemethodologyforextractingsamplesalongthegraincouldresultinamorevi-
xi
