WOOD RESEARCH Volume 61, Number 3, 2016
Lukas Blesak, Kamila Cabova, Frantisek Wald, Sandra R.S. Monteiro, and Alfredo M.P.G. Dias

Transverse loading distribution related to micro-cracks evolution on a timber-concrete slab

Numerical simulation based on a non-linear material behaviour definition of concrete being a part of a coupled timber-concrete load-bearing system is presented in this paper. The main goal of a NL material modelling performed and introduced herein is to define the influence of concrete fragility over transverse loading distribution horizontally a locally loaded slab. The gained knowledge is consequently applied in a local fire exposure problem. Numerical simulations based on both linear elastic (LE) and non-linear (NL) material behaviour are compared with the results obtained from several real-size experiments and the effects of specific phenomena are discussed further. NL material definition of concrete is also termed as a “damaged material model” in certain references. This work is a continuation of the research performed at the Department of Civil Engineering, University of Coimbra, which’s result had been analysed and further published in paper (Dias et al. 2013) and doctoral thesis (Monteiro 2015).

WOOD RESEARCH Volume 65, Number 5, 2020
Tawich Pulngern, Kasan Chanto, Waraluk Pansuwan, and Woraparn Pattaraumpornsak

Effect of lamina thickness on flexural performance and creep behavior of douglas fir glued laminated timber beam

This research presents the effects of lamina thickness on flexural and creep performances of glulam timber. Flexural test results indicated that nonlinear load-displacement curve could be defined as both exponential and power functions. Lamina thickness was not affected to nonlinear curve, especially at initial linear relationship. Slightly different of 2.92% for nonlinear function parameters was obtained. For flexural creep test due to three levels of sustained load for 1,000 hours, only secondary creep stage behaviors without delamination were observed for all glulam timbers while average relative creep was 1.66. Effect of lamina thickness was also not found for creep performance. Finally, creep models have been developed including Bailey-Norton, adjusted Pickel, simplified Pickel, and Dorn models and found that Bailey-Norton and the adjusted Pickel models gave a good correlation with experiment and were the suitable models which could be used to predict long-term flexural creep behavior for various stress levels.