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Prestressed Glulam Beams Reinforced with CFRP Bars

https://research.thinkwood.com/en/permalink/catalogue110
Year of Publication
2016
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Yang, Huifeng
Ju, Dongdong
Liu, Weiqing
Lu, Weidong
Publisher
ScienceDirect
Year of Publication
2016
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Bending
Carbon Fiber Reinforced Polymer
Douglas-Fir
Pre-Stress
Reinforcement
Four Point Bending Test
Research Status
Complete
Series
Construction and Building Materials
Summary
This paper describes an experimental test program and theoretical analysis which examines the reinforcing in flexure of glued laminated timber (glulam) beams using bonded-in carbon fiber reinforced polymer (CFRP) bars. A series of four-point bending tests were conducted till failure on unreinforced, passively reinforced and prestressed Douglas fir glulam beams in a simply-supported scheme. The focus of this research was to evaluate the reinforcing efficiency of both passively reinforced and prestressed beams. Test results showed that the flexural capacity of the reinforced, prestressed, prestressed & reinforced (bottom prestressed and top reinforced) beams greatly increased by 64.8%, 93.3% and 131%, respectively. While the maximum improvement of the bending stiffness reached 42.0%. Another important finding was that the extreme fiber tensile strain of timber beams at failure could be remarkably increased due to the presence of the tension reinforcement, which indicated it overcomes the effects of local defects and therefore the failure mode was changed from brittle tension failure to ductile compression failure. Based on the experimental results, a theoretical model was proposed to predict the flexural capacity of unreinforced, reinforced and prestressed timber beams, which was validated by the test data.
Online Access
Free
Resource Link
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Stress-laminated timber decks in bridges: Friction between lamellas, butt joints and pre-stressing system

https://research.thinkwood.com/en/permalink/catalogue2891
Year of Publication
2020
Application
Decking
Author
Massaro, Francesco Mirko
Malo, Kjell Arne
Organization
Norwegian University of Science and Technology
Publisher
Elsevier
Year of Publication
2020
Format
Journal Article
Application
Decking
Keywords
Stress Laminated
Timber Bridges
Butt-Joint
Stiffness
Friction
Pre-Stress
Research Status
Complete
Series
Engineering Structures
Summary
Stress-laminated timber (SLT) decks in bridges are popular structural systems in bridge engineering. SLT decks are made from parallel timber beams placed side by side and pre-stressed together by means of steel rods. SLT decks can be in any length by just using displaced butt joints. The paper presents results from friction experiments performed in both grain and transverse direction with different levels of pre-stress. Numerical simulations of these experiments in addition to comparisons to full-scale experiments of SLT decks presented in literature verified the numerical model approach. Furthermore, several alternative SLT deck configurations with different amounts of butt joints and pre-stressing rod locations were modelled to study their influence on the structural properties of SLT decks. Finally, some recommendations on design of SLT bridge decks are given.
Online Access
Free
Resource Link
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