Thermo-Mechanical Analysis of Mass Concrete Foundation Slabs at Early Age—Essential Aspects and Experiences from the FE Modelling

Aneta Smolana,Dirk Schlicke,Barbara Klemczak,Miguel Azenha

doi:10.3390/ma15051815

Aneta Smolana, Dirk Schlicke + Show 2 more

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https://doi.org/10.3390/ma15051815

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Abstract

In this paper, the focus is placed on essential aspects of finite element modelling of thermo-mechanical behaviour of massive foundation slabs at early ages. Basic decision-making issues are discussed in this work: the potential need to explicitly consider the casting process in the modelling, the necessary size of the underlying soil to be modelled and the size of the FE mesh, and the need of considering daily changes of the environmental temperature and the temperature distribution over the depth of the soil. Next, the contribution of shrinkage to early age stresses, the role of the reinforcement, and the type of mechanical model are investigated. Comparative analyses aiming to investigate the most important aspects of the FE model and some possible simplifications with negligible effect on the results are made on the example of a massive foundation slab. Finally, the results are summarized with recommendations for creating the FE models of massive slabs at early ages.

Highlights

Modelling of mass concrete at early ages using finite element analysis (FEA) has received a lot of attention among researchers
For the purpose of performing the FE analysis of concrete structures at early ages, usually, user-friendly commercial tools are available, for example, DIANA software, as in [21], where the thermo-hygro finite element framework for predicting the service life performance of reinforced concrete structures was presented, or MIDAS Civil software, which enabled performing the FE analysis of the temperature field in the arch bridge including the parametric analysis of the influence of the ambient temperature, cement type, and convection coefficient [22]
The increased computing capabilities incline to model the structure and processes very precisely, albeit the direct consequence is the rapid growth of the number of input variables, the size of the model, and the time of FE analysis

Summary

Introduction

Modelling of mass concrete at early ages using finite element analysis (FEA) has received a lot of attention among researchers. Some researchers used original programs and procedures dedicated to solving thermo-mechanical problems in early age mass concrete. Such an original finite element procedure for the chemo-thermal model based on the chemical affinity concept was applied in [23] to examine the temperature distribution of the dam during its construction. The original software packages TEMWIL (hygro-thermal analysis) and MAFEM (mechanical analysis) were used in investigations of the early behaviour of reinforced concrete tank walls [24] and slabs [5]

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