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.

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.

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.

Effects of end distance and thickness on the tensile resistance of 102 mm shear plates

1995 ◽  
Vol 22 (6) ◽  
pp. 1113-1119 ◽  
Author(s):  
P. Quenneville ◽  
A. Charron
Keyword(s):  
Experimental Study ◽  
Weibull Distribution ◽  
Key Words ◽  
Tensile Load ◽  
Design Standards ◽  
Unit Clause ◽  
Shear Plate ◽  
End Distance ◽  
Design Requirements ◽  
Two Parameter

In this paper, an experimental study of the behavior of 102 mm shear plates subjected to tensile load is presented. The design requirements for shear plate connectors specified in the last three editions of the Canadian wood design standards (1980, 1984, and 1989) are also reviewed and compared with the experimental results. In the experimental study, 83 specimens were tested with shear plate end distances of 80, 145, 210, and 275 mm. Specimens were either 64 or 89 mm thick. Results for all tests were analyzed and 5th percentile resistance values were obtained for each end distance value, assuming a two-parameter Weibull distribution. Results show that connections using 102 mm shear plate connectors behave in a brittle manner when loaded in tension. It is also shown that the member thickness affects the tensile resistance of shear plates in thin members with small connector end distances and that it appears to impose a limit on the resistance for thin members with large connector end distances. Finally, it is shown that the 75% minimum limit on a member net area adjacent to a connector unit (clause 4.3.7.2 of O86.1-M89) is conservative for members with small connector end distances. Key words: wood, shear plate, end distance, resistance, thickness.

Effectiveness of Virtual Resilience Training on Assertiveness in Student Girls Aged 9–10 Years: A 1-Month Follow-Up

2021 ◽  
pp. 105984052110135
Author(s):  
Shima Gadari ◽  
Jamile Farokhzadian ◽  
Parvin Mangolian Shahrbabaki
Keyword(s):  
Experimental Study ◽  
Internal Stress ◽  
Intervention Group ◽  
The Other ◽  
Hormonal Changes ◽  
Emotional Instability ◽  
Other Hand ◽  
Significant Difference ◽  
Resilience Training

Girls between the ages of 9 and 10 begin to experience physical, physiological, and hormonal changes that may lead to internal stress. At this age, children are struggling for autonomy; on the other hand, they may experience emotional instability, and for these reasons, they may be vulnerable in many ways. This experimental study aimed to investigate the effect of resilience training on assertiveness in student girls aged 9–10. Data were collected before, immediately after, and 1 month after the intervention in the control ( n = 40) and intervention ( n = 37) groups. There was a significant difference between the assertiveness of the intervention immediately (26.80 ± 3.73) and 1 month after the intervention (27.05 ± 3.73), and assertiveness significantly increased in the intervention group ( p = .0001). Resilience training leads to improvements in assertiveness in student girls aged 9–10.

Study of wave attenuation in concrete

1993 ◽  
Vol 8 (9) ◽  
pp. 2344-2353 ◽  
Author(s):  
J-M. Berthelot ◽  
Souda M. Ben ◽  
J.L. Robert
Keyword(s):  
Experimental Study ◽  
Plane Wave ◽  
Wave Attenuation ◽  
Plane Waves ◽  
Propagation Distance ◽  
Experimental Results ◽  
The Other ◽  
Wave Frequency ◽  
Concrete Composition ◽  
Analytical Expression

The experimental study of wave attenuation in concrete has been achieved in the case of the propagation of plane waves in concrete rods. Different mortars and concretes have been investigated. A transmitter transducer coupled to one of the ends of the concrete rod generates the propagation of a plane wave in the rod. The receiver transducer, similar to the previous one, is coupled to the other end of the rod. The experimental results lead to an analytical expression for wave attenuation as function of the concrete composition, the propagation distance, and the wave frequency.

Experimental Study on Racetrack-Shaped Holes Impingement Cooling With Bump Type Roughening Element

2012 ◽  
Author(s):  
Chiyuki Nakamata ◽  
Yoji Okita ◽  
Takashi Yamane ◽  
Yoshitaka Fukuyama ◽  
Toyoaki Yoshida
Keyword(s):  
Experimental Study ◽  
Flow Condition ◽  
Reynolds Numbers ◽  
Main Flow ◽  
The Other ◽  
Relative Location ◽  
Target Plate ◽  
Cooling Effectiveness ◽  
Impingement Cooling ◽  
Cooling Air

Cooling effectiveness of an impingement cooling with array of racetrack-shaped impingement holes is investigated. Two types of specimens are investigated. One is a plain target plate and the other is a plate roughened with bump type elements. Sensitivity of relative location of bump to impingement hole on the cooling effectiveness is also investigated. Experiments are conducted under three different mainflow Reynolds numbers ranging from 2.6×105 to 4.7×105, with four different cooling air Reynolds numbers for each main flow condition. The cooling air Reynolds numbers are in the range from 1.2×103 to 1.3×104.

Tribological Study of Polymer Composite Forming Using Model Experiments and Real Composites

2014 ◽  
Vol 611-612 ◽  
pp. 300-305 ◽  
Author(s):  
Olga Smerdova ◽  
Michael P.F. Sutcliffe
Keyword(s):  
Experimental Study ◽  
Polymer Composites ◽  
Viscous Liquid ◽  
Polymer Composite ◽  
Contact Area ◽  
Essential Feature ◽  
The Other ◽  
Carbon Fabric ◽  
Simultaneous Application ◽  
Composite Forming

This experimental study is focused on identification of tribological mechanisms acting during forming of polymer composites. The range of relevant processes includes fibre placement, tape lay-up, moulding, draping, and RTM. Two types of tribological experiments, relying both on simultaneous application of compression and shear loadings, are carried out. Firstly, model macromechanical tests are undertaken on plastic rods of millimetric diameter immersed in a viscous liquid, representing composite fibres and matrix, respectively. By careful simulation of forming conditions, this experiment helps to identify the friction phenomena occurring in real composites. On the other hand, the micromechanics of forming processes is studied through a microscopic experiment on real carbon fabric. This material is clamped between two glass plates and pulled in opposing directions in the plane of the fabric. It is hypothesized that the evolution of contact area due to shearing that can be measured in this experiment is an essential feature of the tribology of forming processes, a topic which hitherto has not been investigated.

Partial cut harvesting and ectomycorrhizae: early effects in Douglas-fir-larch forests of western Montana

1980 ◽  
Vol 10 (3) ◽  
pp. 436-440 ◽  
Author(s):  
A. E. Harvey ◽  
M. J. Larsen ◽  
M. F. Jurgensen
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Douglas Fir ◽  
The Other ◽  
Western Montana ◽  
Root Tips ◽  
Residue Removal ◽  
Larch Forests ◽  
Early Effects

Numbers of ectomycorrhizae were assessed 3 years after harvesting approximately 50% of the overstory in two Douglas-fir-larch stands in western Montana, one was subjected to intensive residue removal, the other broadcast burned 1 year after harvest. Numbers of active ectomycorrhizal root tips were significantly reduced in the broadcast burned stand compared to either the intensively utilized stand or to an adjacent, undisturbed stand. This indicates that on difficult-to-regenerate sites, particularly where soil organic matter is low, it may be advantageous to dispose of slash created in partial cuts by means other than burning.

The Mindfulness-Based Stress Reduction Program (MBSR) Reduces Stress-Related Psychological Distress in Healthcare Professionals

2010 ◽  
Vol 13 (2) ◽  
pp. 897-905 ◽  
Author(s):  
Andrés Martín-Asuero ◽  
Gloria García-Banda
Keyword(s):  
Experimental Study ◽  
Psychological Distress ◽  
Stress Reduction ◽  
Health Professionals ◽  
Healthcare Professionals ◽  
Training Programs ◽  
The Other ◽  
Reduction Program ◽  
Mindfulness Based Stress Reduction

This semi-experimental study examines how Mindfulness facilitates a distress reduction in a group of health professionals. The sample comprises 29 professionals seeking stress reduction who undertook an 8 weeks psico-educative intervention, involving 28 hours of class, based on a program called Mindfulness-based Stress Reduction or MBSR. Results show a 35% reduction of distress, from percentile 75 to 45, combined with a 30% reduction in rumination and a 20% decrease in negative affect. These benefits lasted during the 3 months of the follow up period. The correlation analysis indicates that the decrease in distress is significantly related to the other two variables. These results confirm the effectiveness of MBSR to decrease distress and its applicability in training programs for health professionals.

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