No abstract

Glass-fiber-reinforced polymer (GFRP) bar has emerged as a preferable alternative to steel bar in reinforced concrete (RC) members in harsh, corrosive, coastal environments in order to eliminate corrosion problems. However, only limited experimental studies are available on the performance and behavior of concrete columns reinforced with GFRP bars under different loading conditions. This study investigates the use of GFRP bars and GFRP helices (spirals) as longitudinal and transversal reinforcement, respectively, in RC columns. A total of 12 circular concrete specimens with 205-mm diameter and 800-mm height were cast and tested under different loading conditions. The effect of replacing steel with GFRP reinforcement and changing the spacing of the GFRP helices on the behavior of the specimens was investigated. The experimental results show that the axial load and bending moment capacity of the GFRP-RC columns are smaller than those of the conventional steel-RC columns. However, the ductility of the GFRP-RC columns was very close to the ductility of the steel-RC columns. It is concluded that ignoring the contribution of the GFRP bars in compression leads to a considerable difference between analytical and experimental results. The experimental results show that the axial load and bending moment capacity of the GFRP-RC columns are smaller than those of the conventional steel-RC columns. However, the ductility of the GFRP-RC columns was very close to the ductility of the steel-RC columns. It Page 2 of 52 is concluded that ignoring the contribution of the GFRP bars in compression leads to a considerable difference between analytical and experimental results.

SUMMARY This paper presents the preliminary research works on a potential seismic isolation method that makes use of scrap rubber tires for the protection of low‐to‐medium‐rise buildings. The method involves mixing shredded rubber tire particles with soil materials and placing the mixtures around building foundations, which provides a function similar to that of a cushion. Meanwhile, the stockpiling of scrap tires is a significant threat to our environment, and the engineering community has been looking for long‐term viable solutions to the recycling and reuse of rubber. A finite element program has been developed for modeling the time‐domain dynamic responses of soil–foundation–structure system, by which the effectiveness and robustness of the proposed method have been evaluated. In general, the structural responses, in terms of acceleration and inter‐story drift, can be reduced by 40–60%. Copyright © 2012 John Wiley & Sons, Ltd.

Sand-tyre chip (STCh) mixtures can be used in many geotechnical applications as alternative backfill material. The reuse of scrap tyres in STCh mixtures can effectively address growing environmental concerns and, at the same time, provide solutions to geotechnical problems associated with low soil shear strength and high dilatancy. In this paper, the shear strength and dilatancy behaviour of STCh mixtures have been investigated. A series of monotonic triaxial tests has been carried out on sand mixed with various proportions of tyre chips. It has been found that tyre chips significantly influence the shear strength and the dilatancy behaviour of STCh mixtures. The effects of confinement and relative density on the shear strength, dilatancy and initial tangent modulus of the STCh mixtures have also been investigated. Moreover, a dilatancy model for STCh mixtures has been proposed and validated with the experimental results.

Composite materials, including Fibre Reinforced Polymer (FRP) bars, have been gaining momentum as alternatives to traditional steel reinforcements in civil and structural engineering sectors. FRP materials are non-corrosive, non-conductive, and lightweight and possess high longitudinal tensile strength, which are advantageous for their use in civil infrastructure. This paper presents the results of an experimental investigation into the effects of the use of glass FRP (GFRP) bars as internal reinforcement on the behaviour of concrete beams. Both static and dynamic (impact) behaviours of the beam have been investigated. Twelve GFRP reinforced concrete (RC) beams were designed, cast and tested. Six GFRP RC beams were tested under static loading to examine the failure modes and associated energy absorption capacities. The remaining six GFRP RC beams were tested under impact loading using a drop hammer machine at the University of Wollongong. GFRP RC beams with higher reinforcement ratio showed higher post cracking bending stiffness and experienced flexural-critical failure under static loading. However, GFRP RC beams under impact loading, regardless of their shear capacity, experienced a "shear plug" type of failure around the impact zone. Energy absorption capacities of beams were determined. The average dynamic amplification factor was calculated as 1.15, indicating higher dynamic moment capacities compared to static moment capacities (15-20% increase). Reinforcement ratio and the strength of concrete influenced the behaviour of GFRP RC beams. -------------------------------------------------------- * Corresponding authors Research Highlights Flexural behaviour of GFRP RC beams has been investigated. Twelve GFRP reinforced concrete (RC) beams were designed, cast and tested. Six GFRP RC beams were tested under static loading to examine the failure modes and associated energy absorption capacities. The remaining six GFRP RC beams were tested under impact loading using a drop hammer machine at the University of Wollongong. GFRP RC beams with higher reinforcement ratio showed higher post cracking bending stiffness and experienced flexuralcritical failure under static loading. However, GFRP RC beams under impact loading, regardless of their shear capacity, experienced a "shear plug" type of failure around the impact zone. Energy absorption capacities of beams were determined. The average dynamic amplification factor was calculated as 1.15, indicating higher dynamic moment capacities compared to static moment capacities (15-20% increase). Reinforcement ratio and the strength of concrete influenced the behaviour of GFRP RC beams.