Effect of end distance on the resistance of split ring connectors in timber joints loaded in compression

1993 ◽  
Vol 20 (5) ◽  
pp. 863-871 ◽  
Author(s):  
Pierre Quenneville ◽  
Alain Charron ◽  
Karl Van Dalen
Keyword(s):  
Engineering Design ◽  
Species Group ◽  
Douglas Fir ◽  
Experimental Program ◽  
Split Ring ◽  
Ring Compression ◽  
Larch Species ◽  
Cleavage Strength ◽  
End Distance ◽  
Timber Joints

An experimental program was undertaken to verify the end distance requirements in the Canadian standard for engineering design in wood for split ring connectors in joints loaded in compression. In a laboratory study, 48 joints of the Douglas fir-larch species group using 63 mm diameter split rings, 45 joints of the Douglas fir-larch species group using 102 mm diameter split rings, and 51 joints of the spruce-pine-fir species group using 63 mm diameter split rings were loaded to failure in compression. The split ring end distance varied between 50 and 200 mm for joints with 63 mm diameter split rings and between 80 and 220 mm for joints with 102 mm diameter split rings. Tests were also carried out to verify the cleavage strength of the wood and the strength of the wood in compression parallel-to-grain for each of the specimens. Results show that the end distance does not have any significant effect on the resistance of split ring connectors in joints with members loaded in compression. Key words: split ring, compression, end distance, timber, resistance.

Effect of end distance on the resistance of spilt ring and shear plate connectors loaded perpendicular to grain

1996 ◽  
Vol 23 (5) ◽  
pp. 989-997
Author(s):  
J. H. P. Quenneville ◽  
J. G. A. Charron
Keyword(s):  
Experimental Study ◽  
Species Group ◽  
Douglas Fir ◽  
The Other ◽  
Limit States ◽  
Split Ring ◽  
Ring Shear ◽  
Shear Plate ◽  
Larch Species ◽  
End Distance

An experimental study was undertaken to verify the end distance requirements in the CSA Standard O86.1-94 "Engineering design in wood (limit states design)" for split ring and shear plate connectors in joints loaded perpendicular to grain. In a laboratory study, 48 joints of the Douglas fir – larch species group were loaded to failure perpendicular to grain. Twenty-eight of those joints were tested using 102 mm diameter shear plates, and the remaining 20 joints were tested using 63 mm diameter split rings. Of the 28 joints tested with 102 mm shear plates, 16 of the specimens were made of laminated Douglas fir and the other 12 specimens were made of sawn lumber Douglas fir. End distances of 80, 130, 140, and 180 mm were studied for each of the two shear plate tests. Specimens using 63 mm split rings were tested at end distances of 80 and 140 mm. Results show that when using 102 mm shear plate and 63 mm split ring connectors, the end distance of the connector has no statistically significant effect on the resistance of the connector. Changes to the Canadian wood design standard are recommended. Key words: wood, fasteners, resistance, split ring, shear plate, end distance.

The enhanced performance of split-ring connections through prestressing

1991 ◽  
Vol 18 (5) ◽  
pp. 830-838 ◽  
Author(s):  
J. H. P. Quenneville ◽  
K. Van Dalen
Keyword(s):  
Key Words ◽  
Engineering Design ◽  
Laboratory Study ◽  
Laboratory Tests ◽  
Simple Technique ◽  
Douglas Fir ◽  
Limit States ◽  
Split Ring ◽  
Lap Splices

This paper examines the concept of enhancing the performance of timber connectors in truss joints by the introduction of transverse prestressing. The behaviour of lap splices of Douglas fir, with 63 mm split-ring connectors and end distances of 50, 100, 150, and 210 mm, was examined for various levels of prestress in a laboratory study. As well, the magnitude of the load that can be carried by the connection through friction between faying surfaces was also assessed for various levels of prestress. The simple technique used in the laboratory for introducing prestress is described. Results of the laboratory tests on 20 joint configurations are presented, and the experimentally determined strengths are compared with the calculated resistances using the provisions of CAN\CSA-086.1-M89 "Engineering design in wood (limit states design)." Key words: timber, connector, prestress, truss joint.

Combined effects of end distance and spacing on the resistance of split ring connectors loaded in tension

1994 ◽  
Vol 21 (5) ◽  
pp. 789-796 ◽  
Author(s):  
A. Charron ◽  
P. Quenneville
Keyword(s):  
Experimental Study ◽  
Key Words ◽  
Engineering Design ◽  
Linear Relation ◽  
Combined Effects ◽  
Split Ring ◽  
Design Standard ◽  
Design Philosophy ◽  
End Distance

An experimental study was undertaken to verify the combined effects of timber connector end distance and spacing requirements of the Canadian standard for engineering design in wood. A total of 130 test specimens using 63 mm diameter split rings were loaded to failure in tension. The split ring end distance varied between 50 and 210 mm and the spacing varied between 80 and 200 mm. Results show that a linear relation exists between the connector end distance and its resistance for a given spacing. Increase in spacing also results in an increase of the connector resistance for a given end distance. Also, connections with two connectors in a row can resist significant loads even if the end distance or spacing of one connector is below the standard minimum required value. Thus, the design philosophy of Clause 10.3.3 of the wood design standard is inadequate for these joints. Key words: split ring, tension, end distance, spacing, resistance, timber.

Fastener head pull-through resistance of plywood and oriented strand board

2002 ◽  
Vol 29 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Y H Chui ◽  
Steven Craft
Keyword(s):  
Oriented Strand Board ◽  
Species Group ◽  
Test Results ◽  
Design Code ◽  
Screw Head ◽  
Timber Joint ◽  
Larch Species ◽  
Significant Difference ◽  
Timber Joints ◽  
Pull Through

A nailed or screwed sheathing-to-timber joint may fail in one of two possible modes when subjected to a load applied along the axis of the fastener: fastener head pull-through of the sheathing material and shank withdrawal from the timber. Currently, the Canadian timber design code does not provide specifications to check the first mode of failure. In this study, tests were conducted to determine the head pull-through strengths of some common hammer and power-driven nails and wood screws in plywood and in oriented strand board. These are compared with the calculated shank withdrawal strengths of the same fasteners from timber, assuming it to belong to the Douglas fir–larch species group. The test results show that there is no significant difference in strengths between plywood and oriented strand board. Head pull-through strength appears to increase with fastener diameter. The major conclusion reached is that, except for small size nails (less than 2 in. long), fastener head pull-through in sheathing prevails over shank withdrawal from timber in sheathing-to-timber joints when loaded axially.Key words: nail, wood screw, head pull-through, withdrawal strength, timber, design capacities.

PULL OUT STRENGTH FOR DIFFERENT SIZE OF DOWEL AND GRAIN DIRECTION OF GLULAM

2016 ◽  
Vol 78 (5-4) ◽  
Author(s):  
Tengku Anita Raja Hussin ◽  
Mohamad Iswandi Jinne ◽  
Rohana Hassan
Keyword(s):  
Failure Modes ◽  
Maximum Load ◽  
Experimental Program ◽  
Drilling Process ◽  
Test Results ◽  
Bond Behaviour ◽  
Pull Out ◽  
Timber Joints ◽  
Different Thickness ◽  
Pull Out Strength

This paper presents an experimental program for testing glued-in dowel glulam timber joints. Hundred thirty glulam specimens, each with a single glued-in rebar parallel to the grain and perpendicular to grain with different size of dowels 12mm, 16mm and 20mm were tested to evaluate the effects of anchorage length and different dowel diameter for parallel and perpendicular to the grain on pull-out strength and bond behaviour of glued-in rebar timber joints. The test results showed that the maximum load for specimen with dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction. Failure modes were characterized by pull out failure in the mode of adhesive-dowel, yet one sample failed in timber-adhesive mode. This might happened because the surface of the timber was burned by drilling machine during the drilling process. The pull-out was tested with different thickness grain direction with different dowel size with a rate of 2mm/min and the failure modes were observed after the testing of pull-out test. PRF is the adhesive used for the strengthening purposes. Resistance to the withdrawal of dowels glued-in perpendicularly was 44.2% to 53.5 % lower than that obtained for dowels glued-in parallel to the grain direction. The result shows that the dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction.

scholarly journals RHS-to-RHS axially loaded X-connections near an open chord end

2017 ◽  
Vol 44 (11) ◽  
pp. 881-892 ◽  
Author(s):  
YuJing Fan ◽  
Jeffrey A. Packer
Keyword(s):  
Closed Form Solution ◽  
Form Solution ◽  
Experimental Program ◽  
Hollow Section ◽  
Design Procedures ◽  
End Distance ◽  
Circular Hollow Section ◽  
Hollow Structural Section ◽  
Connection Design ◽  
Chord Member

In all truss-type welded hollow structural section connection design procedures, the chord member is assumed continuous on both sides of the branch. New limits of applicability have recently been advocated, which specify minimum end distances from an open chord end to achieve the full connection strength. To investigate their suitability for rectangular hollow section (RHS) connections, an experimental program consisting of 12 RHS-to-RHS X-connections subject to branch axial compression was undertaken. For connections near a chord end, a modified yield line mechanism controlled. A proposed analytical model is derived, and by evaluating against the experimental results, is shown to accurately predict the yield loads. An EN 1993-1-8 amendment, transcribed from circular hollow section connections, is deemed excessively conservative, and a closed-form solution for the end distance, presented herein, is recommended for use with RHS connections. Alternatively, providing a cap plate is determined to be an effective stiffening method.

Effect of interface gap on load–slip characteristics of timber joints fabricated with multiple nails

1985 ◽  
Vol 12 (1) ◽  
pp. 104-113 ◽  
Author(s):  
S. K. Malhotra ◽  
B. Thomas
Keyword(s):  
Structural Engineering ◽  
Load Capacity ◽  
Lateral Load ◽  
Experimental Program ◽  
Load Carrying Capacity ◽  
Timber Construction ◽  
Interface Characteristics ◽  
Load Carrying ◽  
Friction Joint ◽  
Timber Joints

An experimental program, exploratory in nature, has been carried out to investigate the effect of interface gap on the load–slip behaviour of joints fabricated with multiple nails. In total, 320 joint specimens have been tested. Modification factors are developed to account for the effects of number of nails and interface gap on the overall load-carrying capacity of joints with multiple nails. The current practice for the design of nailed joints is that a joint fastened together with multiple nails in a row, regardless of the interface characteristics of that joint, carries lateral load equal to the product of the lateral-load capacity of the corresponding joint with a single nail and the number of nails in a row of the joint. The findings of this investigation indicate this practice to be somewhat of an overestimation of the overall capacity of the joint. Key words: design, interface gap, interface friction, joint slip, loads (forces), modification factors, multiple fasteners, nailed joints, stiffness, structural engineering, tests, timber construction.

Nonlinear models fitted to stand volume–age data compare favourably with British Columbia Forest Service hand-drawn volume–age curves

1980 ◽  
Vol 10 (3) ◽  
pp. 304-307 ◽  
Author(s):  
Sagary Nokoe
Keyword(s):  
British Columbia ◽  
Nonlinear Models ◽  
Species Group ◽  
Forest Service ◽  
Douglas Fir ◽  
Stand Volume ◽  
Biological Interpretation

Nonlinear models developed for sigmoid growth and other relationships were applied to stand volume–age data of interior British Columbia Douglas-fir species group. The five nonlinear models used in the study described the data adequately and compared favourably with corresponding hand-drawn volume–age curves of the British Columbia Forest Service. A major advantage of these fitted models over the hand-drawn curves, however, is that the parameters allow biological interpretation.

Behaviour of single and double 102 mm split ring conneotions loaded in tension

1996 ◽  
Vol 23 (3) ◽  
pp. 602-613 ◽  
Author(s):  
J. H. P. Quenneville ◽  
J. G. A. Charron
Keyword(s):  
Key Words ◽  
Significant Influence ◽  
Experimental Studies ◽  
Combined Effects ◽  
Split Ring ◽  
Direct Function ◽  
Design Standard ◽  
Design Philosophy ◽  
End Distance

Two experimental studies were undertaken to verify the effect of the end distance on the resistance of single connector joints using 102 mm split rings and the combined effects of timber connector end distance and spacing on the resistance of double connector joints using 102 mm split rings. A total of 108 test specimens were loaded to failure in tension. Sixty of those tests were single connector joints with end distances varying from 80 to 270 mm. The remaining 48 test specimens were double connector joints with split ring end distances varying from 100 to 270 mm and a spacing of either 125 or 230 mm. The single connector joints results showed an increase in connector resistance with the increasing end distance. However, it was shown that even though some specimens were tested at an end distance below the standard minimum required value (end distance of 80 mm instead of the minimum required of 135 mm), they resisted a significant load. For the double connector joints, it was observed that brittle failures are more common, as opposed to single connector joints which tend to fail showing signs of ductility. Also, results showed that the connection resistance is not a direct function of the number of fasteners and that a factor of 0.475 has to be applied. Results obtained suggested that the end distance does not have a statistically significant influence on the resistance of connections with connector spacing at either 230 or 125 mm. However, the spacing of the connectors appears to affect the resistance. Thus, the design philosophy of Clause 10.3.3 of the wood design standard is inadequate for these particular joints. Recommendations to determine connection resistances are provided. Key words: wood, fasteners, resistance, split ring, end distance, spacing.

Six years of plant community development after clearcut harvesting in western Washington

2009 ◽  
Vol 39 (2) ◽  
pp. 308-319 ◽  
Author(s):  
David H. Peter ◽  
Constance Harrington
Keyword(s):  
Forest Succession ◽  
Plant Cover ◽  
Species Group ◽  
Intermediate Disturbance Hypothesis ◽  
Douglas Fir ◽  
Native Forest ◽  
Vegetation Control ◽  
Clearcut Harvesting ◽  
Species Groups ◽  
Total Tree

What roles do ruderals and residuals play in early forest succession and how does repeated disturbance affect them? We examined this question by monitoring plant cover and composition on a productive site for 6 years after clearcutting and planting Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco). The replicated experiment included three treatments: vegetation control with five annual herbicide applications superimposed over two levels of slash removal (bole only or total tree plus most other wood) and an untreated control. Three species groups were analyzed: native forest, native ruderals, and exotic ruderals. Without vegetation control, the understory was rapidly invaded by exotic ruderals but was codominated by native and exotic ruderals by year 6. Douglas-fir cover surpassed covers in the three species group covers at least 3 years sooner with herbicide treatments than without. Species richness and coverage were lower for all species groups with vegetation control than without vegetation control. The effects of organic matter removal were much less than that of vegetation control. As predicted by the Intermediate Disturbance Hypothesis, repeated vegetation control resulted in declining cover and richness; however, native forest species were surprisingly resilient, maintaining as much or more cover and richness as the ruderal groups.

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