The phenomenon for the wood creep in the reinforced glued wooden structures

Abstract

For the composite structures based on wood, that include reinforced wooden structures, allowance for the influence of wood specific features as a building material allows us to evaluate its structural design as accurately as possible and ensure the required reliability and durability. Creep that causes wood deformations evolving in time can be referred to the specific properties of wood to a greater extent affecting the operation of the reinforced wooden structures. Taking into account the state of the issue to determine the effect of the long-acting loads on the stress-strain state of the reinforced glued wooden structures, the article considers the application of the theory of elastic heredity as the most applicable to assess the deformability of wooden structures in time. The conducted experimental and theoretical investigations and the reinforced glued wooden structures observations during the operational process have shown that their stress-strain state changes significantly under the load over time. Glue compositions used to connect reinforcement with wood ensure their reliable joint operation, however, as the result of the wood creep where wood is the basic material, the redistribution of forces between the reinforcement and wood occurs there on and off. At the same time normal stresses in the reinforcement and the glue joint “reinforcement - wood” increase in the calculated cross sections while they decrease in the wood, which is caused by a change (decrease) in the wood elastic modulus. Allowance for the wood creep in the design of the reinforced wooden structures will allow to determine the stress - strain state of the structure in the design more precisely. Therefore, when developing the reinforced wooden structures design standards, this factor must be taken into account.

Engineering calculations and numerical modeling of composite adhesive plywood panels

“…As a result, the given geometric characteristics of the section are determined using the formulas presented in Table 1. After determining the cross-section of glued plywood panels, all necessary checks are performed for each element according to the conditions of strength and deformability [24], presented in Table 2.…”

Experimental Study on Flexural Performance of the Prestressed Glulam Continuous Beam after Long-Term Loading

“…Creep can reduce the ultimate load and stiffness of glulam members by 13-39.34% and 39.47-55.76% [19], thus affecting the normal use of wood in the field of construction engineering. Based on the studies of the short-term performance of strengthened glulam beams, the creep properties have been investigated [20][21][22][23][24][25][26][27][28]. Yahyaei-Moayyed et al [20] proposed one finite element method which could be used to predict the creep behavior of aramid-fiber-reinforced polymer(AFRP) reinforced wood and examine the short-and long-term performance of the glulam beams reinforced by prestressed FRP-wood composite laminate (PWCL) system.…”

Multi-Span Composite Timber Beams with Rational Steel Reinforcements

“…The creation of new composite products follows market differentiation and filling specific market niches [5][6][7][8]. For example, in Russia, for many years, comprehensive studies of glued wooden reinforced structures have been carried out; new types of them have been developed and implemented in industry [9,10].…”