Determination of temperature loading for crack assessment in soil-immersed concrete structures

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Volume Title

Insinööritieteiden korkeakoulu | Master's thesis

Date

2024-08-19

Department

Major/Subject

Mcode

Degree programme

Master's Programme in Geoengineering (GEO)

Language

en

Pages

81

Series

Abstract

A concrete structure that is designed to last for a hundred years must withstand various actions, including temperature gradients, which may cause cracking. Although such actions are typically addressed in design standards, the Finnish design guidelines do not specify temperature loading for soil-immersed concrete structures like troughs or retaining walls. One of the current engineering approaches is to adopt the loading from the bridge design guidelines and apply it to the linear elastic finite element analysis. This results in excessive reinforcement. The first problem with this method is that the temperature magnitude is too large for soil-immersed structures. And the second problem is that the linear elastic model does not account for stress relaxation due to concrete cracking. The aim of the research is to find out a proper temperature distribution and derive an equivalent temperature loading for crack assessment, applicable for linear finite element analysis. First, the temperature distribution is calculated with a thermal conduction analysis based on annual recorded temperatures, thermal insulation surrounding the structure, and the water content of the soil. Then, the temperature distribution is applied in nonlinear analysis to estimate crack width and required reinforcement. Finally, an equivalent temperature distribution for the corresponding linear analysis is determined by requiring the same amount of reinforcement as predicted by the nonlinear analysis.

Description

Supervisor

Niiranen, Jarkko

Thesis advisor

Gustavsson, Henry
Shahzad, Summer

Keywords

concrete, crack, temperature, loading, trough, soil-immersed

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