Download or read book Strength and Stiffness of Reinforced Yellow poplar Glued laminated Beams written by and published by . This book was released on 1997 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: In bridge applications, it is often necessary to minimize the depth of the bridge structure to provide for the required hydraulic opening or reduce the volume of approach fill. For bridges that utilize structural glued-laminated (glulam) timber beams as stringers, reinforcement using thin strips of pultruded E-glass-fiber-reinforced plastic (GFRP) composites may permit reduced depth, because the reinforcement has the potential to increase stiffness and strength. This study is part of an overall effort aimed at evaluating the potential for commercial production of glulam-GFRP beams in current wood laminating plants and a wood adhesive compatible with existing equipment. Twelve Yellow-Poplar glulam GFRP beams were commercially manufactured, and their performance was evaluated. The GFRP panels were bonded to the wood with a resorcinol formaldehyde adhesive to provide the reinforcement. The simplicity of the process used to manufacture the test beams indicates that the commercial production of glulam-GFRP beams is feasible. Increases of 18 percent in stiffness and 26 percent in strength were achieved by adding 3 percent of GFRP by volume. The bending strength values of the beams predicted by the ASTM D3737 procedure correlate well with the experimental values. However, the observed delamination of the reinforcement indicates that improved bonding strength of wood--GFRP interfaces is needed. Results of this study will be useful to manufacturers interested in improving the performance of glulam timber beams.
Download or read book Strength and Stiffness of Glued Laminated Timber Beams written by Johannes Moe and published by . This book was released on 1961 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Strength Validation and Fire Endurance of Glued laminated Timber Beams written by Erwin L. Schaffer and published by . This book was released on 1986 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A previous paper presented a reliability-based model to predict the strength of glued-laminated timber beams at both room temperature and during fire exposure. This Monte Carlo simulation procedure generates strength and fire endurance (time-to-failure, TTF) data for glued-laminated beams that allow assessment of mean strength and TTF as well as their variability. This paper reports an effort to validate model predictive capability through an independently fabricated set of 21 glued-laminated beams. Based upon the available data for the model input parameters on lumber strength and stiffness, finger-joint strength, and length of laminating lumber between sequential finger joints, the model of beam strength appears acceptable and possibly slightly conservative. Refinements in the beam strength model allow its use for predicting fire endurance. In this case, the fire endurance is measured by the TTF and is defined as the time the beam will support its design load while subjected to fire. The residual strength of the beam is analytically calculated by removing the char layer, plus a finite thickness of weakened wood, from the beam cross section as fire exposure time increases. Employing the input parameters for values of finger-joint strength and lamination grades of Douglas-fir, the fire endurance TTF was analyzed for a 5.12- by 16.50-inch 11-lamination Douglas Fir-Larch beam (24F-V4) carrying full allowable uniform load (47.7 lb/in.). (Three-sided fire exposure was assumed; however, four-sided exposure can also be accommodated.) A simulated random fabrication and analysis of the TTF under fire exposure for 100 beams was performed. The mean TTF was estimated as 35.2 minutes with a coefficient of variation of 13.7 percent. Lateral torsional buckling was never the cause of failure in any of the simulations. The results compared well (within a 65 pct confidence band) with the observations and predictions for timber beams reported by sources in other countries. A simulation for a single glulam beam test in cooperation with the National Forest Products Association was also conducted which predicted the result exactly.
Download or read book Strength and Stiffness of Small Glued laminated Beams with Different Qualities of Tension Laminations written by Catherine M. Marx and published by . This book was released on 1981 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Efficient Utilization of Red Maple Lumber in Glued laminated Timber Beams written by John J. Janowiak and published by . This book was released on 1995 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of the Stiffness of a Roof System Made of Glued laminated Beams and Heavy Timber Decking written by Fred Werren and published by . This book was released on 1961 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance of Red Maple Glulam Timber Beams written by Harvey Bright Manbeck and published by . This book was released on 1993 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Materials and Joints in Timber Structures written by Simon Aicher and published by Springer Science & Business Media. This book was released on 2013-09-25 with total page 815 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the contributions from the RILEM International Symposium on Materials and Joints in Timber Structures that was held in Stuttgart, Germany from October 8 to 10, 2013. It covers recent developments in the materials and the joints used in modern timber structures. Regarding basic wooden materials, the contributions highlight the widened spectrum of products comprising cross-laminated timber, glulam and LVL from hardwoods and block glued elements. Timber concrete compounds, cement bonded wood composites and innovative light-weight constructions represent increasingly employed alternatives for floors, bridges and facades. With regard to jointing technologies, considerable advances in both mechanical connections and glued joints are presented. Self-tapping screws have created unprecedented options for reliable, strong as well as ductile joints and reinforcement technologies. Regarding adhesives, which constitute the basis of the jointing/laminating technology of modern timber products, extended options for tailor-made bonding solutions have to be stated. Apart from melamine-urea and phenolic-resorcinol adhesives, one-component-polyurethanes, emulsion isocyanate polymers and epoxies offer a wide range of possibilities. The contributions dealing with experimental and numerical investigations on static, cyclic and seismic behavior of structures clearly reveal the enhanced potential of modern timber construction for reliable and sustainable buildings and bridges of the new millennium. The book is structured in nine thematic areas, being I) Structures II) Mechanical Connections III) Glued Joints and Adhesives IV) Timber and Concrete/Cement/Polymer Composites V) Cyclic, Seismic Behavior VI) Hardwood, Modified Wood and Bamboo VII) Cross-Laminated Timber VIII) Properties and Testing of Wood IX) Glulam
Download or read book Structural Behaviour of Glued Laminated Timber Beams Reinforced by Compressed Wood written by Buan Anshari and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As an engineered wood product, glued laminated timber (Glulam) is produced to minimise several natural weaknesses such as knots and non-uniform strength in order to enhance its stiffness and load carrying capacity. Many reinforcement methods have been tested, with promising results in increasing the strength and stiffness of beam. Recently, with increasing concern on environmental protection there is a growing trend in construction to use as many natural materials as possible. Therefore, conventional types of reinforcement using metals and/or synthetic materials do not fit well with this trend. A new approach to strengthen Glulam beams using pure natural materials has been established through this research. Glulam beams were strengthened by inserting compressed wood (CW) blocks into the pre-cut rectangular holes on the top of the beams. This practice was to make use of moisture-dependent swelling nature of the compressed wood. As a result, a pre-camber was produced in the mid-span of the beam reinforced. Significant initial tensile and compressive stresses were generated at both the top and the bottom extreme fibres of the beam, respectively. Material tests have been done to investigate material properties of compressed Japanese cedar with different compression ratios. Structural tests were undertaken for short and long Glulam beams strengthened by CW blocks after gained the pre-camber. 3-D finite element models have also been developed by using commercial code ABAQUS to simulate the pre-stressing behaviour of Glulam beams reinforced using compressed wood blocks. The finite element models were used to simulate the structural behaviour of the pre-stressed beams subjected to subsequent destructive bending tests. All computer models developed were validated against corresponding experimental results of the free moisture-dependent swelling, pre-stressing processes and the destructive tests for both the short and long beams. Reasonably good correlation was obtained in terms of the free swelling, the pre-camber, initial stress state of the Glulam beams reinforced and load-deflection relationships. Using validated computer models, parametric studies were further carried out to provide design information for such a reinforcing technique. The results have indicated that the reinforcing techniques using compressed wood blocks are very effective means to enhance the initial stiffness, bending strength and load carrying capacity of Glulam beams. The technology is ready to be applied in practice.
Download or read book Improved Utilization of Lumber in Glued Laminated Beams written by Russell Charles Moody and published by . This book was released on 1977 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flexural Strength of Glued laminated Timber Beams Containing Coarse grain Southern Pine Lumber written by R. C. Moody and published by . This book was released on 1974 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Destructive evaluation of 20 beams provided data on which to base strength factors for the coarse-grain southern pine. This lower quality material, which is defined as having fewer than four rings per inch, has not previously been used in the manufacture of engineered glued-laminated timber. In comparison to existing glued-laminated combinations, beams containing coarse-grain lumber are likely to have slightly reduced bending strength and stiffness values and substantially reduced shear strength. (Modified author abstract).
Download or read book Bending Strength of Water soaked Glued Laminated Beams written by Ronald W. Wolfe and published by . This book was released on 1978 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reliability Formulation for the Strength and Fire Endurance of Glued laminated Beams written by and published by . This book was released on 1985 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model was developed for predicting the statistical distribution of glued-laminated beam strength and stiffness under normal temperature conditions using available long span modulus of elasticity data, end joint tension test data, and tensile strength data for laminating-grade lumber. The beam strength model predictions compared favorably with test data for glued-laminated beam strength data with 8 and 10 laminations; however, the model predicted strength values 30 percent higher for glued-laminated beam strength data with 4 laminations. Fire endurance and structural resistance were evaluated by artificially reducing the cross section. This reduction accounts for char depth as well as for reduced wood strength caused by the elevated temperature. Average time-to-failure predictions using the developed model compared well with those from conventional prediction methods.
Download or read book Glass Fiber Reinforced Glued Laminated Wood Beams written by Alfred B. Dorey and published by . This book was released on 1996 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of a previous investigation showed that the use of glass fibre reinforcement in laminated wood beams should be investigated in detail. This report describes a subsequent research project that investigated the improvement in mechanical properties of laminated wood specimens with glass fibre reinforcing. Specifically, the project evaluated the strength & stiffness enhancement of beam specimens by comparing the properties of reinforced and unreinforced beams. The test program studied specimens reinforced with glass fibre along the extreme tension wood fibre at varying amounts of fibre or fibre fractions; specimens with similar fibre fractions, but reinforced along both the extreme tension wood fibre and the extreme compression wood fibre; specimens with a different base size of laminated beam to determine sizing effects, if any; and specimens exposed to adverse environmental conditions to determine the effectiveness of the reinforcing systems to environmental exposure. In addition, a model was developed to predict the failure load of the reinforced specimens. Model predictions are compared to the experimental results.
Download or read book Flexural Properties of Glued laminated Southern Pine Beams with Laminations Positioned by Visual stiffness Criteria written by Russell Charles Moody and published by . This book was released on 1970 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Variation of mechanical properties in oak boards and its effect on glued laminated timber written by Cristóbal Tapia Camú and published by Cuvillier Verlag. This book was released on 2022-03-23 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The renewable material wood and hereof derived structural engineered wood products (EWPs) is widely acknowledged as being the major pillar of sustainable building constructions. Due to an increasing availability and high mechanical performance the wood resource hardwoods has been gaining traction for the use in EWPs, typically dominated by softwoods. Wood, being a naturally grown material, exhibits a pronounced variation in its mechanical properties, presenting marked differences not only between species, but also between individual trees and locally throughout the stem of each tree. Glued laminated timber (GLT) reduces this variation by vertical glue-stacking previously finger-jointed boards to form a highly homogenized wooden beam. This configuration reduces considerably the variation of the observed global mechanical properties of GLT with respect to the individual boards. However, the rather complex material composition of GLT prohibits the derivation of an analytical relation between local (e.g. intra board and finger-joints) and global properties, thus numerical approaches need to be applied. This work addresses the need for an improved understanding and modeling approach of the variability of stiffness and strength along and between boards, and the resulting impact on the size-effect of GLT made of oak.
Download or read book Design criteria for large structural glued laminated timber beams using mixed species of visually graded lumber written by Russell Charles Moody and published by . This book was released on 1974 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
