Publications

This study examines the structural performance of concrete slabs and beams reinforced with various types of reinforcement under centrally concentrated loading until failure. Three types of reinforcement were studied, including steel meshes (A142), steel fibers (30 kg/m3), and macro polypropylene (PP) fibers (6 kg/m3). The study discusses the fracture behavior of ground slabs and the enhancement in performance resulting from the inclusion of PP and steel fibers in terms of load–strain and load–deflection responses, deflection profiles, and crack patterns. In addition, the study compared the flexural behavior of fiber-reinforced concrete beams to determine the effectiveness of using various fibers in beams and slabs. The results revealed a significant increase in the flexural strength of steel fiber or steel mesh reinforced slabs on the ground as compared to the reference specimen while slabs reinforced with PP fibers showed favorable results in post-cracking performance and energy absorption compared to steel fibers. The use of PP fibers, steel fibers, and steel meshes can improve the flexural cracking strength of concrete slabs by 28%, 47%, and 79%, respectively. However, predictions based on the beam tests and physical properties of steel mesh overestimated the flexural strength of ground slabs by 12%, while the corresponding predictions of PP fiber-reinforced slabs and steel fiber-reinforced slabs were 45% and 24% higher than the experimental results. This study provides insights into the performance of different types of reinforcements in concrete slabs and beams, which can be valuable in designing and constructing reinforced concrete structures.

This study investigates the impact behaviour of bridge decks constructed with ultra-high-performance concrete (UHPC) and fibre-reinforced polymer (FRP) stay-in-place (SIP) formwork. Eight scaled bridge decks were fabricated and tested under pendulum impacts. Two different FRP SIP formwork configurations, i.e., square hollow section (SHS) and Y-shaped stiffened, were considered. Two types of reinforcing bars, i.e., steel and glass FRP (GFRP), were adopted for these samples. The influence of impact velocity on the transient response and progressive damage of the concrete decks under impact loading was investigated. The test results showed that UHPC and Y-shaped stiffeners were effective in decreasing the peak and residual displacements of decks by up to 70 % when compared to decks made with normal strength concrete. UHPC and Y-shaped stiffeners greatly improved the impact and residual impact capacities. The use of GFRP rebars instead of steel reinforcement changed the failure mode and FRP SIP formwork reduced deck damage and mitigated scabbing failure under impact loads. The configuration of FRP SIP formwork had a substantial influence on the impact force and thus the deck's performance. Especially, this study has observed an interesting phenomenon under impact, i.e., reaction force could be greater than impact force, which has not been reported in the literature yet.

Different behaviour of diverse sections of confined Reinforced Concrete (RC) columns under eccentric load is investigated in this study.Three types of sections are considered, which include square columns, square with rounded corners and modified circular columns. Twelve reinforced square concrete columns were made from normal strength concrete and subdivided into four groups.The first three columns were the Reference Group andhadnomodification.The next three columnsweremodifiedwith round corners andwrappedwith three layers of Carbon Fibre Reinforced Polymer (CFRP), another three were bonded with four pieces of segmental circular concrete covers and wrapped with three layers of CFRP, and the last three were bonded with concrete covers and confined with steel straps. All columns were tested under concentric loading, 15mm and 25mm eccentric loading. Results from the study show that all confinement methods increase capacity and ductility of columns, in which segmental circular concrete covers considerably reduce the stress concentration on the corners and increase the efficiency of the confinement. Effect of eccentric load on the specimens wrapped with FRP is significantly higher than the Reference Group.

It is always a challenge to efficiently and accurately estimate the force on structures from falling objects. This study aims to predict the maximum impact force on reinforced concrete beams subjected to drop-weight impact using artificial neural network. A new empirical model including a comprehensive version and a simplified version is proposed to estimate the maximum impact force. The model was verified against a database collected from the literature including 67 reinforced concrete beams tested under drop-weight impacts. The database covers the concrete strengths ranging from 23 to 47 MPa, the projectile mass from 150 to 500 kg, and the impact velocity up to 9.3 m/s. The prediction of the comprehensive version of the proposed model fits the experimental results very well with an average absolute error of 11.6%. The simplified version of the proposed model is established for easy estimation, with the average error of 23.2% in prediction of the maximum impact force.

This study aims to investigate the structural behavior and failure modes of fiber-reinforced-polymer (FRP) confined concrete wrapped with different FRP arrangements. A total of twenty four specimens were cast and tested, with three of these specimens acting as reference specimens and the remaining specimens wrapped with different types of FRP (CFRP and GFRP) by different wrapping arrangements. They include fully wrapped, partially wrapped and non-uniformly wrapped concrete cylinders. The non-uniformly wrapped concrete cylinders provided higher compressive strengths and strain for FRP-confined concrete, in comparison with conventional fully wrapping arrangements. The effect of confinement level on the effectiveness of FRP confinement is also investigated. In addition, the partially wrapping arrangements changes the failure modes of the specimens and the angle of the failure surface.