Title: Cover and Stirrup Effects on the Shear Response of Dowel Bar Embedded in Concrete

Author(s): Sandro Dei Poli, Marco Di Prisco, and Pietro G. Gambarova

Publication: Structural Journal

Volume: 90

Issue: 4

Appears on pages(s): 441-450

Keywords: cover; dowels; reinforced concrete; stirrups; shear forces; Structural Research

DOI: 10.14359/3962

Date: 7/1/1993

Abstract:
The efficiency of dowel action in shear transfer in cracked reinforced concrete structures depends strongly on the confinement exerted by the surrounding concrete, as well as on the hoop action of the stirrups. In spite of the many test data obtained to date in this field, several aspects of dowel behavior are still open to further investigation, since dowel/cover/stirrup interaction is a manifold problem, especially when the dowel bar pushes against a thin concrete cover. Within this framework, 28 reinforced concrete specimens reinforced with a single deformed bar 14, 18, and 24 mm in diameter (#5, 6, and 8) were tested as a part of a major research program on dowel action. Block-type specimens were loaded according to displacement-controlled procedure. Dowel displacements were detected by means of a set of linear variable differential transducers (LVDTs) touching the dowel bar through concrete-embedded ducts. The results consist of force-displacement curves, displacements and curvature diagrams along the axis of the bar, linear regressions of dowel ultimate capacity, and initial stiffness versus bar diameter. Finally, comparisons with several available models predicting dowel strength are presented, and design values for the subgrade stiffness of the concrete embedment are proposed.