Influence of Footing Dimensions on Early-Age Temperature Development and Cracking in Concrete Footings

摘要

This article presents the findings of an investigation that used finite-element analysis to determine the influence of a concrete footing's dimensions on its temperature development and cracking at early age. A three-dimensional finite-element model was used to predict temperatures in the footing and to assess cracking potential of the concrete. A parametric study consisting of 63 finite-element analyses was conducted on three different footing shapes: (1) a cubic shape, (2) a length: width: depth ratio of 4: 4: 1, and (3) a length: width: depth ratio of 4:2:1. Volume-to-surface area ratios (v/a) ranged from 0.33 to 4.0 m. The results showed that cracking potential does not depend on a footing's dimensions when its v/a is 1.3mor greater. Rectangular footings that have the same v/a but different shapes (dimensional proportions) developed a similar maximum temperature, a similar maximum temperature differential, and a similar minimum crack index under the same insulation condition. Smaller footings allowed slightly higher maximum temperature differential before thermal cracking occurred. (C) 2014 American Society of Civil Engineers.