Load Duration and Seasoning Effects on Mortise & Tennon Joinery

Table of Contents Page
Page
1. Introduction.................................................................................................................. 1
1.1. TIMBER FRAME INTRODUCTION/HISTORY........................................................................................1
1.2. PURPOSE/NEED OF RESEARCH..........................................................................................................2
1.3. LITERATURE REVIEW .......................................................................................................................4
1.4. OBJECTIVES AND SCOPE...................................................................................................................7
1.5. OVERVIEW .......................................................................................................................................8
2. Joint Tests (Eastern White Pine)................................................................................ 10
2.1. INTRODUCTION...............................................................................................................................10
2.2. TEST FRAME SET-UP ......................................................................................................................11
2.3. SHORT TERM TEST PROCEDURE.....................................................................................................12
2.4. FAILURE MODES ............................................................................................................................13
2.5. ANALYSIS METHODS (5% OFFSET).................................................................................................15
2.6. RESULTS.........................................................................................................................................16
2.7. DOWEL BEARING STRENGTH..........................................................................................................18
2.8. DETAILING REQUIREMENTS (END/EDGE/SPACING)........................................................................20
2.9. JOINT STRENGTH CORRELATION ....................................................................................................20
3. Spring Theory............................................................................................................. 23
3.1. THEORY/POSSIBLE USES ................................................................................................................23
3.2. TEST PROCEDURES.........................................................................................................................24
3.3. METHOD AND RESULTS..................................................................................................................26
4. Long Term <strong>Seasoning</strong>/Creep Tests............................................................................. 32
4.1. INTRODUCTION...............................................................................................................................32
4.1.1. Test Frame Set-up..................................................................................................................33
4.1.2. Joint Preparation...................................................................................................................34
4.1.3. Monitoring <strong>and</strong> <strong>Load</strong> Adjustment Procedure ........................................................................36
4.2. DOUGLAS FIR .................................................................................................................................37
4.2.1. <strong>Load</strong>ing <strong>and</strong> <strong>Load</strong> <strong>Duration</strong>..................................................................................................37
4.2.2. Moisture Content...................................................................................................................40
4.2.3. Results <strong>and</strong> Conclusions of Time-Deflection Behavior .........................................................42
4.3. SOUTHERN YELLOW PINE ..............................................................................................................44
4.3.1. <strong>Load</strong>ing <strong>and</strong> <strong>Load</strong> <strong>Duration</strong>..................................................................................................44
4.3.2. Moisture Content...................................................................................................................47
4.3.3. Results <strong>and</strong> Conclusions of Time-Deflection Behavior .........................................................49
4.4. WHITE OAK....................................................................................................................................51
4.4.1. <strong>Load</strong>ing <strong>and</strong> <strong>Load</strong> <strong>Duration</strong>..................................................................................................52
4.4.2. Moisture Content...................................................................................................................56
4.4.3. Results <strong>and</strong> Conclusions of Time-Deflection Behavior .........................................................58
4.5. EASTERN WHITE PINE ....................................................................................................................59
4.5.1. <strong>Load</strong>ing <strong>and</strong> <strong>Load</strong> <strong>Duration</strong>..................................................................................................60
4.5.2. Moisture Content...................................................................................................................64
4.5.3. Results <strong>and</strong> Conclusions of Time-Deflection Behavior .........................................................65
4.6. GENERAL LONG-TERM CONCLUSIONS ...........................................................................................66
5. Failure Testing of Long Term Specimens .................................................................. 68
5.1. TEST PROCEDURE/ANALYSIS .........................................................................................................68
5.2. DOUGLAS FIR .................................................................................................................................68
5.2.1. Joint Properties <strong>and</strong> Results..................................................................................................68
5.2.2. Material Properties (Dowel Bearing Strength <strong>and</strong> MC) .......................................................69
5.3. SOUTHERN YELLOW PINE ..............................................................................................................70
5.3.1. Joint Properties .....................................................................................................................70
5.3.2. Material Properties (Dowel Bearing Strength <strong>and</strong> MC) .......................................................72
5.4. WHITE OAK....................................................................................................................................72
5.4.1. Joint Properties .....................................................................................................................72
5.4.2. Material Properties (Dowel Bearing Strength <strong>and</strong> MC) .......................................................73
5.5. EASTERN WHITE PINE ....................................................................................................................73
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