Behaviour of Concrete Flat Plates Reinforced with GFRP Headed-End Bars

Ensuring proper anchorage of slab reinforcement in slab-column edge connections is essential because of the interruption in the slab continuity. Meanwhile, glass fibre-reinforced polymer (GFRP) bars have emerged as an effective alternative to traditional steel reinforcement, offering a durable solution to the problem of corrosion in reinforced concrete (RC) structures. However, the provisions for reinforcement anchorage, particularly GFRP, introduce detailing challenges due to the required development length. Therefore, GFRP headed-end bars were developed to provide better anchorage between concrete and GFRP reinforcement. Two full-scale isolated slab-column edge connections reinforced with GFRP headed-end bars were constructed and tested to failure under a combination of gravity loads and unbalanced moments. The slabs had dimensions of 2800 × 1550 × 200 mm and were connected to a column stub measuring 300 × 300 mm, which projected 1000 mm top and bottom of the slab surface. The main test parameter was the flexural reinforcement ratio (0.9 or 1.8%). Both slab-column connections were subjected to the same moment-to-shear ratio of 0.4 m. The performance of the connections was evaluated in terms of capacity, mode of failure, deflections, and strains in both concrete and reinforcement. The behaviour of test specimens was compared with slab-column connections reinforced with GFRP bent bars from the literature. It was demonstrated that the connection constructed with GFRP headed-end bars as flexural reinforcement behaved similarly to its counterpart with bent bars. Moreover, an increase in the reinforcement ratio led to enhanced axial load capacity and improved post-cracking stiffness of the connection.