The Structural Engineer > Archive > Volume 59 (1981) > Issues > Issue 13 > Shrinkage and Tension Stiffening in Negative Moment Regions of Composite Beams
Name of File 4115-59-13.pdf cached at 16/12/2017 16:58:14 - with 7 pages. pdfPath: E:\k9.istructe.org\CMS\webtest\files\c5\c5831626-38b0-48d5-889d-e1900b814a48.pdf. thumbPath: E:\k9.istructe.org\CMS\webtest\files\pdfthumbs\c5831626-38b0-48d5-889d-e1900b814a48_1.png. objDoc: 1 - True. objPreview.Log: . strFileName: c5831626-38b0-48d5-889d-e1900b814a48_1.png

Members/subscribers must be logged in to view this article

Shrinkage and Tension Stiffening in Negative Moment Regions of Composite Beams

Results are given of bending tests in the elastic range on seven composite beams with the concrete slab in tension. They show that, when cracks in the concrete first occur, they are wider than would be predicted by the existing theory for cracking in reinforced concrete members. The reason is that cracking releases the locked-in stresses due to the restraint of shrinkage of the slab by the steel beam. When account is taken of this, the accuracy of the methods of BS 5400: Part 5 for the prediction of hogging curvature and mean tensile strain at a given bending moment, is much improved. It is shown in another paper that these results also enable the widths and spacings of cracks in the concrete slab to be predicted more accurately. R.P. Johnson and R.W. Allison