<p>Twelve large-scale reinforced concrete (RC) specimens
were tested at Purdue University’s Bowen Laboratory to evaluate the
deformability of structural walls with longitudinal lap splices at their bases.
Eight specimens were tested under four-point bending and four 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, irrespective of what loading method was used or what splice details
were chosen. 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. </p>
<p>Approximations of wall
drift-strain relationships are presented in combination with estimates of
splice strength and deformability to provide lower-bound drift capacity
estimates for RC walls with lap splices at their bases. Deformations in slender
structural walls (with aspect ratios larger than 3) are controlled by flexure.
Shear deformations must be considered for walls with smaller aspect ratios. For
slender walls with lap splices comparable to those tested, the observations
collected suggest that drift capacities can be as low as 0.5%. That is: splices
with minimum concrete cover, minimum transverse reinforcement (0.25% transverse
reinforcement ratio) terminating in hooks, and lap splice lengths selected to
reach yielding in the spliced bars (approximately 60 bar diameters for splices
of Grade-60 reinforcement) can fail as yield is reached or soon after. For
splices of the same length, doubling the amount of hooked transverse
reinforcement increases deformation capacity by nearly 50%. By maintaining the
same transverse reinforcement ratio but confining splices with closed hoops
(instead of hooks), deformation capacity nearly doubles. Increasing splice
length increases the expected splice strength but also increases the strain
required to reach the same drift ratio. </p>
<p>Evidence from this and
similar experimental programs suggests that lap splices with minimum cover and
confined only by minimum transverse reinforcement terminating in hooks should
not be used in critical sections of structural walls when toughness is
required. To prevent abrupt failure during events that demand structural
toughness, it is recommended that lap splices be shifted away from locations
where yielding in structural walls is expected.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/14495286 |
| Date | 27 April 2021 |
| Creators | William G Pollalis (10709154) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Drift_Capacity_of_Reinforced_Concrete_Walls_with_Lap_Splices/14495286 |
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