Probabilistic mechanical modelling of concrete creep based on the boundary element method

Abstract

The prediction of the future structural behaviour is an essential activity during the design phase. In this study, a novel numerical framework is proposed for investigating the future structural behaviour of two-dimensional structures. The model utilizes the boundary element method for obtaining the mechanical responses. The constitutive material is admitted to manifest viscoelastic response, which enables it to creep. The input parameters such as material, loads parameters and geometry dimensions are considered to possess random characteristics. A probabilistic criterion is proposed using metamodelling by the response surface method. All these features make the proposed numerical model more realistic. As an application, a specific structure is utilized, which is inspired from the real world. The results demonstrate that small geometric deviations do not necessarily impact the global reliability of the structure. At the same time, load estimations have major influence on the global structural reliability. The numerical framework proposed can be utilized for preliminary investigations on the design phase in order to aid the engineers into the decision-making process. Moreover, these observations demonstrate that the boundary element method can be efficiently coupled to other numerical strategies in order to elaborate new robust numerical frameworks able to represent realistically engineering problems.

Shear contribution on viscoelastic behavior of beams modeled using plane frame elements with Reissner kinematics

“…One of these parts is associated with the normal stress effects and the other is associated with the shear stress effects. In 2D elasticity problems the uncoupling between volumetric and deviatoric parts is usual (Oliveira et al, 2018). Thus, there is a schematic interpretation for the adoption of uncoupled models for each of these effects.…”

“…Authors model the elastic behavior based on spherical tensors and the deviatoric constitutive relation based on Boltzmann model. Oliveira et al (2018) investigate future structural behavior of two-dimensional structures considering Boltzmann model applied to creep analyses. Shear effects in a concrete viaduct segment is modeled.…”

Reliability-based fracture analysis for plate bending problems with the dual boundary element method

“…Due to the effectiveness of the DBEM in fracture analysis, it has been extensively used in the research community mainly for problems involving 2D problems. Examples include topology optimisation [1], reliability analysis of structures subjected to fatigue [2], shape optimisation of hydrofoils [3], and the modelling of creep in concrete [4].…”

A multi-fidelity boundary element method for structural reliability analysis with higher-order sensitivities

“…These advantages, and others, are discussed in more detail in previous works concerning sensitivity analyses with geometric variables involving: elastostatic structures [1,5,6], fatigue crack growth [7,8,9], creep [10], plate bending [11], and topology optimization [12].…”

“…The surrogate model is typically created by evaluating the response of the real model at several points, called design points/sites. Types of metamodels that have been employed in the past with regards to structural reliability analysis include polynomials [6,10,17,18,19], Kriging [20,21,22], and Neural Networks (NNs) [23,24]. Although surrogate models are not as accurate as the real model over the entire domain being investigated, they can act as very effective substitutes for the real model over a small part of the domain.…”