Reliability assessment and updating of notched timber components subjected to environmental and mechanical loading

Abstract

Cracking initiation and propagation are frequently recognized as main causes leading to failure of timber structures. Since the kinematics of both processes is largely influenced by environmental conditions, a comprehensive reliability assessment of notched structures should take into account such environmental factors. The main purpose of this paper is to propose a methodology for reliability assessment and updating of notched timber components based on mechanical (A-integral formulation) and reliability (simulation and Bayesian networks) methods, and experimental data. The A-integral formulation is used to estimate energy release rates in modes I and II by taking into account thermal effects; but its numerical implementation is time-consuming for uncertainty propagation. In order to deal with this problem, Bayesian networks were used for reliability assessment and updating. The experimental data used for updating purposes were obtained from measurements of deflection, temperature and relative humidity on a notched beam (Douglas Fir specie) exposed to outdoor environment and constant loading. The whole proposed methodology was illustrated with the reliability assessment and updating of the studied notched beam. The results indicated that the proposed approach is able to integrate measurements of temperature and deflection for reliability updating.

Bayesian Assessment of the Effects of Cyclic Loads on the Chloride Ingress Process into Reinforced Concrete

“…The proposed methodology is based on the Bayesian network (BN) approach, which is a probabilistic tool that could be used to identify parameters by integrating experimental data. The Bayesian approach has already been used to update/identify the parameters of chlorination models, and to assess/update the reliability of concrete [27,28] or timber [29,30] structures. However, it has not been used to estimate the effects of mechanical loading on the chloride ingress mechanism by using experimental data.…”

Analytical Assessment of Creep Behavior of European Species in Outdoor Conditions

“…Wood is defined as a material whose the mechanical behavior in structure depending on the fluctuation of its internal moisture content [1][2]. It is also known that the internal changes of humidity, coupling with long term loading bring in many times, the initiation and the propagation of cracks, which are directly an impact on the total deflection measured on the wood until its collapse [3][4]. These cracks are amplified by the geometric singularities available on the wood and are at the origin of the total collapse of the structure.…”

Notched-beam creep of Douglas fir and white fir in outdoor conditions: Experimental study

“…6b), and the whole setup was installed outdoors, close to the Laboratory building (Fig. 6c) as presented by [26]. The deflection and the climatic parameters (RH, T) were monitored continously, while crack opening, crack length and MC were collected manually every day.…”