Title:
Post-Cracking Shear Capacity of Precast Hollow-Core Floor Units (Prepublished)
Author(s):
Mohamed Mostafa, Richard S. Henry, and Kenneth J. Elwood
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
hollow-core; post-cracking behavior; precast concrete; prestressed concrete; residual shear strength; seismic assessment; shear failure; web cracking
DOI:
10.14359/51749308
Date:
11/6/2025
Abstract:
Precast concrete hollow-core floor units have been shown to sustain cracking in their unreinforced webs near the end support during earthquakes. Post-cracking shear strength is essential to maintain gravity loads following earthquakes. This paper presents the results of an experimental program that examined the post-cracking shear capacity of twelve full-scale hollow-core floor units. Variables included different support seating lengths, shear span-to-depth ratios, and loading protocols. Results showed that cracking in the unreinforced webs of hollow-core floor units can reduce shear capacity by at least 60% relative to uncracked strength. Additionally, reduced support seating length markedly decreased post-cracking shear strength, with 30 mm seating providing no residual capacity, while 50 and 100 mm lengths retained approximately 50 and 100% of the uncracked section capacity, respectively. The findings from this study provide a basis to quantify the residual capacity of web-cracked hollow-core floor units, which can be used in post-earthquake structural assessments.