Behaviour of truss plate and metal web joints in machine-stress-rated lumber trusses

1985 ◽  
Vol 12 (3) ◽  
pp. 700-716
Author(s):  
F. J. Keenan ◽  
M. M. Lepper ◽  
A. T. Quaile ◽  
E. N. Aplin
Keyword(s):  
Relative Density ◽  
Key Words ◽  
Modulus Of Elasticity ◽  
Failure Modes ◽  
Modulus Of Rupture ◽  
Design Values ◽  
Species Groups ◽  
The Mean ◽  
C 30 ◽  
Product Standard

In project A, 1500 pieces of 38 × 89 mm spruce–pine–fir lumber from three mills, in two machine-stress-rated (MSR) grades, 1650f–1.5E and 2100f–1.8E, were proof-loaded to obtain the mean modulus of elasticity, the fifth percentile modulus of elasticity, and the fifth percentile modulus of rupture. Relative density was measured for each piece, and values of the 33.3 and 52.3 percentiles of the relative density ranges were determined for each species/grade category and related to the minimum values stipulated by the National Lumber Grades Authority (NLGA) Special Product Standard SPS-2-82 for machine-stress-rated lumber. The values of relative density at the 33.3 and 52.3 percentiles that will cause the NLGA mean modulus of elasticity MOE (mean), criterion to be just barely satisfied were estimated.In project B, the lateral resistances of 480 truss plate joints were determined. The variables were two common types of truss plates (thicknesses of 0.91 mm and 1.5 mm) in two grades of MSR lumber (1650f–1.5E and 2100f–1.8E) subdivided into two species groups (pine alone and spruce–fir combined), tested at four orientations of load to grain and load to plate axis. These tests showed that, in most cases, an increase in the design capacity of truss plates in MSR lumber over the values now used for spruce–pine–fir lumber is justified.In project C, 30 commercially designed metal web floor trusses of three span/depth combinations were tested to determine their stiffnesses and strengths. Trusses with 2100f grade lumber in the chords were stiffer than the trusses with 1650f chords. In both grades, larger trusses are relatively less stiff than smaller trusses. With respect to strength, the results indicate that higher design values may be used with higher grades of MSR lumber provided that design is governed by either tooth withdrawal at the joints or by chord strength. An improved analytical model, taking into account four distinct failure modes, is required for the behaviour of floor trusses. Key words: machine-stress-rated lumber, truss plates, trusses, metal webs, strength, density.

scholarly journals Variations in Physico-Mechanical Properties of Lonchocarpus sericeus (Poir), a Lesser-Used Species in West Africa

2021 ◽  
Vol 71 (3) ◽  
pp. 252-261
Author(s):  
Lawrence Olanipekun Aguda ◽  
Babatola Olufemi ◽  
Babatunde Ajayi ◽  
Olajide Rasaq Adejoba ◽  
Adedeji Robert Ojo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Modulus Of Elasticity ◽  
Bending Strength ◽  
High Strength ◽  
Modulus Of Rupture ◽  
Wood Age ◽  
Lonchocarpus Sericeus ◽  
The Mean ◽  
End Use

Abstract This study investigates the properties of Lonchocarpus sericeus to determine its potential use for timber. Three matured trees of L. sericeus were selected from a forest located in Longe Village, Oluyole Local Government Area in Oyo State, Nigeria. Discs from the harvested trees were collected at the base (10%), middle (50%), and top (90%) and further partitioned into inner wood, center wood, and outer wood. An investigation was carried out to characterize the wood age, density, shrinkage, impact strength, modulus of elasticity, modulus of rupture, compressive, and shear strength. The ages were 28, 29 and 32 years. The mean wood density at 12 percent moisture content was 836.63 kg/m3, which shows that it belongs to the high-density wood category. The mean shrinkage values in the radial, tangential, and longitudinal directions were 2.50, 3.99, and 0.78 percent respectively; the volumetric shrinkage was 6.36 percent. These shrinkage values were indicative of good dimensional stability. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel to grain, and maximum compression strength parallel to the grain were 24.14, 114.18, 11,276, 12.76, and 47.16 N/mm2, respectively. End-use assessments suggest that the wood species can be used in similar applications as well-known timbers. The study found L. sericeus to be very dense with high strength in comparison to well-known timbers. It was observed that the mechanical properties of the species decrease from the base to the top and also increase from the outer wood to the core wood.

Structural characteristics of wood composite I-beams

1993 ◽  
Vol 20 (4) ◽  
pp. 574-581
Author(s):  
Robert W. Clinch
Keyword(s):  
Key Words ◽  
Modulus Of Elasticity ◽  
Structural Characteristics ◽  
Slash Pine ◽  
Effective Modulus ◽  
Flexural Stiffness ◽  
Wood Composite ◽  
Wood Composites ◽  
The Mean ◽  
The Web

In this study, wood composite I-beams consisting of F11 slash pine flanges and either hardboard or particleboard webs were fabricated and evaluated for flexural stiffness. Prior to fabrication, both the web and flange materials were evaluated for flexural stiffness. The mean modulus of elasticity of the flange material was 16 900 MPa, while that for the particleboard and hardboard was 4250 and 4450 MPa respectively. The mean effective modulus of elasticity for the particleboard-webbed beams was 16 300 MPa and for the hardboard-webbed beams was 16 400 MPa. The implications of the findings are discussed. Key words: wood composites, I-beams, characterization.

Pengaruh Tekanan dan Penggunaan Conplast terhadap Sifat Mekanik Eternit dari Abu Cangkang Sawit

2016 ◽  
Vol 8 (15) ◽  
pp. 47-54
Author(s):  
Haspiadi Haspiadi
Keyword(s):  
Mechanical Properties ◽  
Oil Palm ◽  
Modulus Of Elasticity ◽  
Modulus Of Rupture ◽  
Palm Shell ◽  
Oil Palm Shell ◽  
Density Values ◽  
Test Result

The purpose of this research is to know the influence of pressure and use of conplast against mechanical properties which are a Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) of plasterboard. The study is done because still low quality of plasterboard made from a mixture of ashes of oil-palm shell especially of the mechanical properties compared to the controls. The method of this reserach used variation of printed pressure and the addition of conplast. Test result is obtained that the highest value of Modulus of Elasticity (MOE) 90875.94 Kg/cm2, Modulus of Rupture (MOR) 61.16 Kg/cm2 and density values in generally good printed at the pressure 60 g/cm3 and the addition of conplast 25% as well as the composition of the ash of palm shell oil 40%: limestone 40%: cement 15%: fiber 5% and 300 mL of water. ABSTRAK Tujuan dari penelitian ini adalah untuk mengetahui pengaruh tekanan dan penggunaan conplast terhadap sifat mekanik yaitu kuat lentur dan keteguhan patah eternit berbahan dasar abu cangkang sawit. Penelitian ini dilakukan karena masi rendahnya mutu eternit berbahan campuran abu cangkang sawit dari bolier khususnya sifat mekanik dibandingkan dengan kontrol. Metode penelitian yang digunakan adalah dengan variasi tekanan cetak dan penambahan conplast. Hasil uji diperoleh bahwa kuat lentur tertinggi sebesar 90875,94 Kg/cm2 dan keteguhan patah sebesar 61,16 Kg/cm2, yang dicetak pada tekanan 60 g/cm3 dan penambahan conplast 25% dengan komposisi  abu cangkang sawit 40 %: kapur 40 % : semen 15 %: serat 5 % dan air 300 mL.Kata Kunci :  Abu cangkang sawit, conplast, kuat lentur, keteguhan patah.

KNOWLEDGE, ATTITUDE AND PRACTICES OF CARETAKERS AND HEALTH PROFESSIONALS TOWARD TEETHING IN INFANTS

2011 ◽  
pp. 52-59
Author(s):  
Binh Bao Son Bui
Keyword(s):  
Sleep Disturbance ◽  
Key Words ◽  
Breast Feeding ◽  
Health Professionals ◽  
Feeding Problems ◽  
Central Hospital ◽  
Pediatric Department ◽  
Correct Knowledge ◽  
The Mean

Objective and methods: a prospective questionnaire based study on 71 parents (caretakers) of consecutive children treated at the Pediatric Department, Hue Central Hospital and on 47 health professionals at the department was conducted from September until December 2009 to investigate the knowledge, attitude and practices of the caretakers, nurses and postgraduated doctors toward teething in infants. Results: Most responders believed that teething causes fever, irritability, feeding problems, drooling, biting, sleep disturbance, swollen gums, crying, lose of appetite for solids; and fever over 38oC was also believed to be associated with teething. The mean eruption time of the first tooth was from 6 months. Most caretakers had normal attitude to manifestations ascribed to teething (54.9%). The most common management to symptoms attributed to teething included increased breast-feeding, oral paracetamol, increased fluid supplying and physician consulting. Conclusion: Correct knowledge to teething in infants need to be educated for parents (caretakers) and even for health professionals. Key words: knowledge, attitude, practices, teething, infants.

CLINICAL CHARACTERISTICS OF THE CHRONIC DACRYOCYSTITIS AND THE SUCCESS RATE OF EXTERNAL DACRYOCYSTORHINOSTOMY

2015 ◽  
pp. 29-34
Author(s):  
Van Nam Phan ◽  
Ba Kien Tran
Keyword(s):  
Success Rate ◽  
Key Words ◽  
Clinical Characteristics ◽  
Lacrimal Duct ◽  
Interventional Study ◽  
Chronic Dacryocystitis ◽  
External Dacryocystorhinostomy ◽  
The Mean

Purpose: To determine the clinical characteristics of the chronic dacryocystitis and the success rate of external dacryocystorhinostomy. Methods: The retrospective, interventional study without comparing on 27 patients (32 eyes) of chronic dacryocystitis who underwent dacryocystorhinostomy (DCR) from 2010 to 2011. Results were evaluated with standards: epiphora, purelence, lacrimal duct irrigation. Results: Over period of 6 months, 27 patients including 25 (92.59%) female, 2 (7.41%) male. The mean age was 49.8 years (range, 22-79 years). All patients demonstrated epiphera (range, 3 months – 11 years). Dacryocystorhinostomy was performed unilaterally in 81.48%, bilateral 18.52%. Successrate was 90.06% overall. Conclusions: Although techniques in dacryocystorhinostomy of DUPUY-DUTEMPS is old, its result is mainstay of treatment for chronic dacryocystitis in Vietnam. Key words: Dupuy-Dutemps, chronic dacryocystitis

RESULTS OF INTRALESIONAL TRIAMCINOLONE ACETONIDE FOR CHALAZION TREATMENT

2011 ◽  
pp. 100-104
Author(s):  
Thi Thu Nguyen ◽  
Viet Hien Vo ◽  
Thi Em Do
Keyword(s):  
Success Rate ◽  
Key Words ◽  
Triamcinolone Acetonide ◽  
Lower Eyelid ◽  
Upper Eyelid ◽  
Interventional Trial ◽  
The Mean ◽  
First Time

The study use intralesional triamcinolone acetonide injection proceduce for chalazion treatment.1. Objectives: To evaluate results of intralesional triamcinolone acetonide injection for chalazion treatment. 2. Method: This noncomparative prospective interventional trial included 72 chalazions of 61 patients. 3. Results: 61 patients (72 chalazions) with 19 males (31.1%) và 42 females (68.9%), the mean age was 24 ± 9,78 years. 31.1% patients was the first time chalazion and 68.9% patients was more than one times chalazion including 78.6% patients was recurrent at the first position and 21.4% patients occur at new position. 72 chalazions with 16 (22.2%) chalazions was treated before and 56 (77.8%) chalazions wasn’t done that. 72 chalazions with 49 chalazions (68.1%) are local in upper eyelid and 23 chalazions (31.9%) are local in lower eyelid. The mean of chalazion diameter is 6.99 ± 3.03mm. Intralesional triamcinolone acetonide is injected to treat 72 chalazions with 16 (22.2%) chalazions are injected through the route of skin and 56 (77.8%) chalazions are injected through the route of conjunctiva. After 2 weeks follow-up, the success rate was 93.1% and 6.9% failed. 4. Conclusion: intralesional triamcinolone acetonide injection for chalazion treatment is really effective. Key words: chalazion, intralesional triamcinolone acetonide.

DISTRIBUTIONS OF MODULUS OF ELASTICITY AND MODULUS OF RUPTURE IN FOUR MILL RUN LUMBER POPULATIONS

2019 ◽  
Vol 51 (2) ◽  
pp. 183-192 ◽  
Author(s):  
Frank C Owens ◽  
Steve P Verrill ◽  
Rubin Shmulsky ◽  
Robert J Ross
Keyword(s):  
Modulus Of Elasticity ◽  
Modulus Of Rupture

scholarly journals Population density of helminths in ducks: effects of host’s age, sex, breed and season

1970 ◽  
Vol 6 (1) ◽  
pp. 45-51 ◽  
Author(s):  
T Farjana ◽  
KR Islam ◽  
MMH Mondal
Keyword(s):  
Population Density ◽  
Key Words ◽  
Parasitic Infection ◽  
Winter Season ◽  
Helminth Parasites ◽  
Domestic Ducks ◽  
The Mean

 A study was conducted to investigate the population density of helminth parasites in domestic ducks (Anas boschas domesticus) in relation to host's age, sex, breed and seasons of the year from March 2002 to May 2003. A total of 300 ducks were collected from different villages of Netrokona and Mymensingh districts of Bangladesh and autopsied to collect the parasites and counted to determine the population density of parasites. Off 300 ducks examined, 290 (96.66%) were infected with 17 species of helminth parasites in which 11 species were trematodes, 4 were cestodes and 2 nematodes. Among the parasites, density of cestodes was the highest (33.15±5.26), followed by trematodes (5.98±1.32); and nematodes (2.95±0.68). Mean density of parasites increased with the increase of age (young: 21.23±1.09, adult: 26.18±2.14 and old: 27.87±2.98) while the mean density of most of the helminth parasites was higher in female ducks (31.35±4.72) than in males (27.52±3.32). Indigenous ducks (33.72±3.61) were infected with the highest load of helminths than Khaki Campbell breed (29.61±4.32) of ducks. Mean density of most trematodes (5.42±0.80) were highest in winter season whereas mean density of all cestodes (48.43±4.85) and nematodes (4.13±1.76) were highest in summer.  The present study suggests that age, sex, breed of ducks and seasons of the year influence the parasitic infection to a greater extend. Key words: Population density, helminths, duck, Bangladesh DOI = 10.3329/bjvm.v6i1.1338 Bangl. J. Vet. Med. (2008). 6 (1): 45-51

Medium Density Particleboard with Addition of Impregnated Paper

2014 ◽  
Vol 1025-1026 ◽  
pp. 543-546
Author(s):  
Juliana Cortez Barbosa ◽  
Anderson Luiz da Silva Michelon ◽  
Elen Aparecida Martines Morales ◽  
Cristiane Inácio de Campos ◽  
André Luis Christoforo ◽  
...  
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Mechanical Tests ◽  
Modulus Of Rupture ◽  
Medium Density ◽  
Test Results ◽  
Thickness Swelling ◽  
Adhesion Test ◽  
Layer Medium ◽  
Determine Moisture Content

The aim of this research was to produce three-layer Medium Density Particleboard (MDP), with the addition of impregnated paper, in the inner layer, in proportions of 1; 5 and 20%. In this study, MDP was composed with particles of small size in outer layers, and larger particles in internal layer. After panel manufacturing, physical and mechanical tests based on Brazilian Code ABNT NBR 14.810 were carried out to determine moisture content; density; thickness swelling; water absorption; modulus of rupture (MOR) and modulus of elasticity (MOE) in static bending and internal adhesion. Test results were compared to commercial panels, produced with 100% Eucalyptus, considering the requirements specified by Brazilian Code. Properties presented values close to normative specifications, indicating positively the possibility of production of MDP using addition of waste paper impregnated.

Mechanical Properties and Decay Resistance of Wood Polymer Composites (WPC)

2011 ◽  
Vol 264-265 ◽  
pp. 819-824 ◽  
Author(s):  
Md. Rezaur Rahman ◽  
Sinin Hamdan ◽  
M. Saiful Islam ◽  
Md. Shahjahan Mondol
Keyword(s):  
Polymer Composites ◽  
Young’S Modulus ◽  
Modulus Of Elasticity ◽  
Young's Modulus ◽  
Decay Resistance ◽  
Modulus Of Rupture ◽  
Wood Polymer ◽  
Static Young’S Modulus ◽  
Wood Polymer Composites ◽  
Wood Polymer Composite

In Malaysia, especially Borneo Island Sarawak has a large scale of tropical wood species. In this study, selected raw tropical wood species namely Artocarpus Elasticus, Artocarpus Rigidus, Xylopia Spp, Koompassia Malaccensis and Eugenia Spp were chemically treated with sodium meta periodate to convert them into wood polymer composites. Manufactured wood polymer composites were characterized using mechanical testing (modulus of elasticity (MOE), modulus of rupture (MOR), static Young’s modulus) and decay resistance test. Modulus of elasticity and modulus of rupture were calculated using three point bending test. Static Young’s modulus and decay resistance were calculated using compression parallel to gain test and natural laboratory decay test respectively. The manufactured wood polymer composites yielded higher modulus of elasticity, modulus of rupture and static Young’s modulus. Wood polymer composite had high resistant to decay exposure, while Eugenia Spp wood polymer composite had highly resistant compared to the other ones.

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