Comportamiento mecánico de juntas frías lisas de concreto

A Torres,F Prada-Sarmiento,A Ramos-Cañón,M Botía-Díaz

doi:10.4067/s0718-50732016000300001

A Torres, F Prada-Sarmiento + Show 2 more

Open Access

https://doi.org/10.4067/s0718-50732016000300001

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Abstract

A smooth cold joint of concrete is an untreated weak plane caused by an interruption of the casting process, which can significantly affect the performance of a structural system. In this paper, the problem of the generation of cold joints is approached from two complementary perspectives. a) The loss of resistance due to the occurrence of cold joints is quantified through an extensive experimental program of concrete cylinders and b) a constitutive model is proposed and its performance is analyzed to simulate the time-dependent behavior of concrete under load (viscosity) and no load (setting). A loss of resistance over 30% for cold concrete cylinders with diagonal joints was found, while concrete cylinders with horizontal cold joints had no loss of resistance. Thus, the loss of resistance depends on the orientation of the cold joint with respect to the direction of the main stresses. This aspect is explained by the proposed constitutive model of viscous–reactive type, which is able to simulate the results of the experimental program. This work opens the possibility of numerical modeling of boundary value problems of structures with a cold joint and to study their influence on the structure’s overall stability.

Highlights

A smooth cold joint of concrete is a weak plane caused by an interruption in the casting process
It is worth noting that the simulation of concrete with cold joints, using a viscoelastic model to relate the material’s stresses and strains, only shows congruent results when the material is subjected to compressive strength
The experimental tests demonstrated that cylinders with horizontal cold joint subjected to compressive strength do not show a loss of resistance in any case

Summary

Introduction

A smooth cold joint of concrete is a weak plane caused by an interruption in the casting process. It is widely recognized that difficulties in the constructive method of concrete structures can entail cold joints that impair the structural performance, since it reduces the system’s stress-strain characteristics (Harsem, 2005). The loss of mechanical properties caused by the presence of cold joints can compromise the structural integrity of the building (Volz and Olson, 2008). The loss of resistance due to the occurrence of cold joints in concrete is quantified through an extensive experimental program with concrete cylinders. This paper shows a lower limit of the mechanical behavior of the interruption, since both the experiments and the numerical analysis are made with smooth cold joint. Revista Ingeniería de Construcción Vol 31 No3 Diciembre de 2016 www.ricuc.cl smooth cold joint is the worst scenario and, it establishes minimum values that must be considered when facing the analysis of a cold joint and when the fact of being treated or not is unknown

Experimental tests

Proposed constitutive model

Numerical simulations – comparison with experiments and discussion

Findings

Conclusions