Title:
Prestress Losses in Aged Hollow-Core Slabs and Their Long-Term Performance after Strengthening
Author(s):
Lang Liu, Xuelian Chen, Xuanwen Liu, and Qingyuan Li
Publication:
Structural Journal
Volume:
123
Issue:
4
Appears on pages(s):
295-307
Keywords:
hollow-core slab; long-term performance; prestress loss; probability density evolution method (PDEM); structural strengthening
DOI:
10.14359/51750658
Date:
7/1/2026
Abstract:
Prestressed hollow-core slabs (PHCSs) were extensively employed in residential construction in earlier decades, yet the extent of prestress loss in these aged structures that have experienced long-term service remains unquantified, despite its governing influence on structural performance. With the current emphasis on renovating aging residential areas, various retrofitting approaches were proposed to enhance loading capacities and extend service life; however, the long-term performance of such strengthened structures requires thorough investigation. This study examines five full-scale PHCSs through comparative experimental testing: two unstrengthened specimens, two carbon fiber-reinforced polymer (CFRP)-strengthened specimens, and one composite slab-strengthened specimen. A two-phase loading protocol, combining low-level cyclic loading and monotonic loading, is implemented to evaluate prestress loss and ultimate capacity. The experiment reveals an average prestress loss of 17.64%, and CFRP strengthening and superimposed strengthening yield immediate improvement of cracking load by 25% and 58%, respectively. The experimental results are validated by numerical simulations and compared with theoretical calculations specified in design codes. Furthermore, upon experimental and simulation results, a probability density evolution method (PDEM)-based approach is developed to assess time-dependent structural reliability, incorporating material degradation models and inherent uncertainties. The proposed methodology enables accurate estimation of prestress loss in aged PHCSs and systematically evaluates the long-term performance of different strengthening methods.
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