Model for the Simulation of the Time-Dependent State in RC Elements

Ante Džolan,Mirela Galić,Alen Harapin

doi:10.3390/app12031501

Ante Džolan, Mirela Galić + Show 1 more

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https://doi.org/10.3390/app12031501

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Abstract

The paper presents an upgrade of the previously developed model for nonlinear 3D analysis of concrete structures extended with the possibility of simulation of the long-term effects (shrinkage and creep) under long-term static load. The origin model is based on the so-called multi-surface principle with modified Rankin criterion for dominant tensile influences (appearance and development of cracks) and the modified Mohr-Coulomb criterion for dominant compressive states (yielding and cracking of concrete). The material behaviour is described with elementary material parameters (modulus of elasticity, Poisson’s coefficient and uniaxial compressive and tensile strength of concrete) by standard tests. Sufficient accuracy along with a simple and effective description of the very complex behaviour of reinforced concrete structures, make this model advantageous. Creep and shrinkage are based on the procedure given by the fib Model Code 2010 and extended with a special extension for non-linear creeping. Two simple examples show the capabilities of the model, while a good agreement between numerical and experimental results indicates that the developed model can well describe long-term effects in reinforced concrete structures, and that the model is appropriate for standard engineering practice.

Highlights

When analysing the behaviour of concrete, it is very important to consider its timedependent behaviour
When we speak about the ‘time-dependent behaviour of concrete’, we often think of creep and shrinkage, which are two main time-dependent physical properties of concrete
According to Rankin’s law, a crack occurs when at least one of the principal stresses exceeds the tensile strength of concrete

Summary

Introduction

When analysing the behaviour of concrete, it is very important to consider its timedependent behaviour. Concrete changes the stress and deformation states over time, i.e., it adapts to the external load. Numerical models cost significantly less and can be used numerous times with different material characteristics, different loads and other parameters. Numerical Model for Concrete for Dominant Tensile Influences. One of the most commonly used models for describing behaviour of concrete structures under dominant tensile stress is Rankin’s material law. According to Rankin’s law, a crack occurs when at least one of the principal stresses exceeds the tensile strength of concrete. In areas where other stresses are compressive, the tensile strength of concrete must be reduced (Figure 1).

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