Cracking in Concrete Tension Flanges of Composite T-Beams
The results of about 8000 measurements of crack width on eight composite T-beams subjected to negative (hogging) bending are analysed, and related to the established relationships that are the basis for current methods of crack width prediction for reinforced concrete beams, slabs, and tension members. Many departures from these relationships were found, especially at low tensile strains. The influence of shrinkage of concrete on crack width is greater than in reinforced concrete members. New methods were devised for predicting both mean and design crack widths. The observed crack widths are much greater than those predicted by the method of BS 5400: Part 5. This finding needs to be checked by study of continuous members in service.
Professor R.P. Johnson and R.W. Allison