NEHRP Clearinghouse

Title
Shear Transfer Under Monotonic Loading, Across an Interface Between Concretes Cast at Different Times.
File
PB275257.pdf
Author(s)
Mattock, A. H.
Source
National Science Foundation, Washington, D.C., September 1976, 70 p.
Identifying Number(s)
SM76-3
Abstract
The total study is concerned with the shear transfer strength of reinforced concrete subject to both single direction and cyclically reversing loading, the latter simulating earthquake conditions. The primary topics studied were the influence of the existence in the shear plane of an interface between concretes cast at different times, and the influence of reinforcing bar diameter on shear transfer across a crack in monolithic reinforced concrete. This Part I of the Final Report is concerned with shear transfer under monotonic, single direction loading, across an interface between concretes cast at different times. Push-off tests were made of both composite and initially cracked monolithic specimens made of normal weight concrete. The interface of the composite specimens was either roughened to comply with Sec. 11.15 of ACI 318-71, or was smooth. In each case, tests were made in which the interface was either bonded and initially cracked, unbonded and initially uncracked, or unbonded and initially cracked. It was found that if the interface was roughened, then the shear transfer strength was very close to that of comparable initially cracked, monolithic push-off specimens, for all interface conditions. If the interface was smooth then the shear transfer strength was much reduced and was approximately equal to the shear yield strength of the reinforcement.
Keywords
Shear transfer; Earthquake engineering; Loads (Forces); Reinforced concrete; Shear properties; Concrete construction; Precast concrete; Cracks; Shear strength