Title: Temporal evolution of cracking in prestressed concrete studied using a continuous-damage approach
Date Published: November - December 2019
Volume: 64
Issue: 6
Page Numbers: 27 - 44
Authors: Junying Rao, Chi Chen, and Tongyan Pan
https://doi.org/10.15554/pcij64.6-01

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Abstract

The stringent control of cracking in prestressed concrete demands more research to investigate the mechanism and evolution of cracking in concrete under combined prestressing and loading conditions. For the first time, continuous damage theory is applied to quantitatively depict the time-dependent cracking behavior of prestressed concrete. A 3-D finite element method (FEM) micromechanical model based on the continuous damage theory was created for a prestressed concrete slab using a 3-D imaging–based approach developed for reconstructing a concrete microstructure. Three major time-dependent prestress losses—tendon relaxation, concrete shrinkage, and concrete creep—were determined explicitly using the developed 3-D FEM micromechanical model. Based on the determined deformation, principal strain, and level of cracking of the concrete slab, it was found that the time-dependent prestress losses significantly affect the cracking behavior of prestressed concrete. Stress growth resulting from prestress losses could cause chronic concrete cracking in service even if the initial prestress applied in concrete was well below its cracking limit. Of the three major types of prestress losses, concrete shrinkage plays a more critical role in causing continuous cracking in prestressed concrete. The 3-D FEM micromechanical model has the potential for wide adoption for designing prestressed concrete structures because, for example, concrete cracking can be more accurately predicted in design.