Pollalis, William and Pujol, Santiago, "Drift Capacity of Structural Walls with Lap Splices" (2020). Bowen Laboratory Research Reports. Paper 2.
Date of this Version
Reinforced Concrete, Lap Splice, Structural Wall, Drift Capacity, Concrete, Shear Wall, Wall, Deformation Capacity, Structures, Engineering, Structural Engineering
Twelve large-scale reinforced concrete specimens with lap splices in the longitudinal reinforcement were tested at Purdue University’s Bowen Laboratory to produce data to evaluate the deformability of structural walls with lap splices at their base. Previous work on lap splices has focused mainly on splice strength. But in consideration of demands requiring structural toughness (e.g. blast, earthquake, differential settlement), deformability is arguably more important than strength.
To obtain data on splice deformability and to study the response of lap splices in conditions more representative of those occurring in structural walls, eight specimens were tested under four-point bending and four additional specimens were tested as cantilevers under constant axial force and cyclic reversals of lateral displacement. All specimens failed abruptly by disintegration of the lap splice regardless of how the loading was controlled or what detailing was used. Large numbers of loading cycles in the linear range of response did not seem to have an appreciable effect on splice deformability. For structural walls with lap splices comparable to those tested, the observations collected suggest that drift capacity can be as low as 0.5% for splices with minimum cover, minimum transverse reinforcement terminating in hooks, and lap splice lengths selected to reach yielding in the spliced bars. That is, splice failure can occur as yield is reached or soon after. For lap splices 1.3 times longer, drift ratio at splice failure is projected to increase to approximately 0.75% or more. For cover twice as large and transverse reinforcement that is continuous around the lap splice, drift capacity is projected to increase to nearly 1% for splices designed to yield and 1.5% or more for lap splices 1.3 times longer.
The evidence gathered suggests that lap splices with minimum cover and confined only by minimum transverse reinforcement terminating in hooks should not be used in applications requiring toughness in structural walls.