Application of GFRP rebar in Jazan Flood Mitigation Channel in Saudi Arabia
Composite rebar (straight and bent type) for reinforcement of Jazan Flood Mitigation Channel (FMC) with a total length of 21.3 km. Overall project includes over 11 million meters of glass fibre-reinforced polymer (GFRP) rebars with diameter Ø13 mm.
The new Jazan Economic City (JEC) is located about 725 km south of the city of Jeddah and 80 km from Jazan city, an industrial and commercial hub with a busy port on the Red Sea. The region is prone to flooding due to poor drainage and heavy seasonal rainfall. A 21.3 km long FMC was constructed in southwest Saudi Arabia on the outskirts of JEC, and it played a vital role in protecting infrastructure and the community who live in the city.
Jazan FMC is the world’s largest project to use GFRP composite rebar as its concrete reinforcement. The client of this project is Saudi Aramco, and Pultron of Dubai, Dextra of China and Galen of Russia as the majority supplier of GFRP rebar to reinforce the concrete channel.
Properties of GFRP rebars
GFRP is a composite, normally comprising vinyl ester resin and glass fibers. The use of GFRP bars as a concrete reinforcement has gained popularity in recent years, as designers have gained confidence in the material and advances in manufacturing processes and increased competition have made it more cost-competitive with conventional reinforcing steel. In addition to corrosion resistance, GFRP bars offer a high strength-weight ratio, electromagnetic neutrality, and high fatigue endurance. Further, the low weight of bars reduces costs for transportation and installation. While thermal expansion and stiffness compatibility with concrete are quite good, GFRP bars have a relatively low elastic modulus, shear strength, and tensile creep rupture stress.
Three international GFRP bar vendors were approved based on their product quality, technical capabilities, and localization plan. The vendors and important properties of the supplied bars are listed in Table 1.
Table 1 Properties of the GFRP bars as provided by three manufacturers
A move to corrosion-free infrastructure
Saudi Aramco, one of the largest companies in the world commenced its non-metallic initiative with a goal of reducing the annual cost of corrosion by 10%. Mandating the use of GFRP rebar is part of their non-metallic initiative, a positive step towards fighting corrosion and moving towards a more sustainable approach to infrastructure builds.
The channel marks a significant turning point in the infrastructure sector. It is one of many large scale projects choosing GFRP rebar for its concrete reinforcement worldwide.
Al Yamama Company won the contract to build the channel. In construction, they poured over 1,500m3 of concrete per day in one of the fastest channel construction projects ever undertaken. Over 11,000,000 linear metres of GFRP from the three international company were delivered – about 82% straight rebar 18% bent rebar.
Evolving design changes
With any project of this size comes inevitable changes. Last minute design changes and quantity revisions led to the need to scale up production levels to meet delivery dates. An extra automated grinder units and a new bends machine installed in order to rapid product GFRP rebars with the expertise and support of our engineering and research partner, Pultron Composites. The increase in production was easily achieved so it could comfortably meet construction scheduling deadlines.
Another source of attention was the shape of the FMC. The design called for an expansion joint in each slab and as a result it needed to supply a shape of bend that bends back onto itself. Typically, this is not possible but after some testing by pultrusion experts, this complex bend was achieved. The bars were preformed and supplied in time to the project.
Positive outcomes using GFRP rebar
Corrosion-free and with high chemical resistance – a design life cycle of 100 years for the channel is assured with little maintenance requirements due to the durability of using high performance glass fibre-reinforced polymer rebar. The Jazan FMC will safeguard people and the city from damage caused by flooding.
After almost 3 years of project execution, Saudi Aramco and the contractor, jointly investigated the costs, advantages, and disadvantages of completing the project using GFRP bars in lieu of epoxy-coated steel rebars. GFRP option resulted in a cost reduction of about 11% for reinforcing bars, 10% for concrete, 42% for bar ties, 100% for crane charges, and 67% for labor based on a 30 x 30 x 0.2 m slab panel. The total direct cost savings for the GFRP bar option was therefore 21%. If considering the life-cycle cost analysis, the cost savings will be more remarkable. For other similar, large-scale projects, a significant reduction in cost could also be achieved with GFRP reinforcing bars.