Measuring crack width and spacing in reinforced concrete members

Syed Yasir Alam (1) , Thibault Lenormand (1) , Ahmed Loukili (1) , J.P. Regoin (1)

1 GeM - Institut de Recherche en Génie Civil et Mécanique

Cracking behavior of reinforced concrete is usually understood by the cracking of a concrete prism reinforced with a central bar subjected to tension. Bending, which is majority of the real cases, is dealt in the Eurocode by an empirical adjustment of the coefficients. In this paper an experimental program is devised to study the structural size effect of reinforced concrete members on crack width and spacing. Bending tests are performed on three different sizes of beams which are geometrically similar in two dimensions. The main reinforcement ratio is constant in all the beams keeping the same number of bars. The cover to the main reinforcement is also scaled with the beam size. Crack width and cracks spacing are measured using digital image correlation technique. Strain in the main reinforcement is measured using embedded electric strain gauges. It is found that Eurocode underestimates the crack width and crack spacing. Measured values of crack widths show an important structural size effect, which is not accounted by Eurocode crack width formula.

Domaines: Mécanique des structures [physics.class-ph]; Mécanique des structures [physics.class-ph]

Syed Yasir Alam, Thibault Lenormand, Ahmed Loukili, J.P. Regoin. Measuring crack width and spacing in reinforced concrete members. 7th International conference on Fracture Mechanics of Concrete and Concrete Structures (FraMCoS-7), May 2010, Jeju, North Korea. pp.377-382. ⟨hal-00683652⟩