Shear behavior of deep precast/prestressed concrete hollow-core slabs with and without fibers at ambient and under fire conditions

• Main Author: Nguyen, Thi Nguyet Hang
• Other Authors: Tan Kang Hai
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Civil engineering
• Online Access: https://hdl.handle.net/10356/138125
• Institution: Nanyang Technological University

This study investigates shear behavior of deep PCHC slabs with and without fibers at ambient and under fire conditions with an emphasis on web-shear behavior. The main objectives are to (1) gain in-depth understanding of web-shear mechanisms of deep PCHC slabs at ambient and in the event of fire and (2) to investigate the potential use of polypropylene (PP) and steel fibers as a shear-strengthening technique to enhance web-shear capacity of PCHC slabs at both ambient and fire conditions. To achieve the objectives, an experimental program consisting of 27 full-scale tests on 21 hollow-core specimens with and without fibers, divided into 4 series, was carried out. While the first two series investigated shear behavior of conventional PCHC slabs at ambient (Series I) and under fire conditions (Series II), the last two series studied shear mechanisms of fiber-reinforced-concrete (FRC) hollow-core slabs at both ambient (Series III) and in the event of fire (Series IV). The effectiveness of using PP and steel fibers on enhancing shear strength of PCHC slabs was then quantified. Besides the experimental studies, test data obtained from Series I, II, and IV were used to verify finite element (FE) models developed to simulate shear behavior of PCHC slabs. The FE models, in turn, helped to shed light on shear mechanisms of PCHC slabs at ambient and under elevated temperatures. Furthermore, based on results and observations from the experimental and numerical studies, two semi-analytical approaches were proposed to predict shear strength of PCHC slabs with and without steel fibers. The models were verified using test data from this study and from published literature. It is shown that the proposed models provide reasonable predictions for shear strength of PCHC slabs with and without steel fibers and can be adopted in design codes.