Composites Hit the Road to Replace Steel in Manhole Covers

Structural Science Composites (SSC) Ltd. has developed manhole and drain covers to replace the traditional steel covers on roadways in England. The manhole covers consist of thermosetting urethane acrylate resin and use Scott Bader Co. Ltd.’s Crestapol resin. To make the manhole covers, a full resin transfer molding (RTM) process is used, giving the strength-to-weight ratio, surface details and anti-slip finish required for these types of access covers. SSC’s composite design uses its patented Thrubeam design, which produces a stiffer beam in combination with glass fiber reinforcement and the high-performance properties of Scott Bader's acrylic resin. The covers in SSC’s Thrubeam lineup typically only weigh a quarter to a third as much as steel or concrete covers, thus simplifying installation and maintenance. SSC claims that combining its Thrubeam technology with a custom-grade Crestapol resin resulted in glass fiber reinforced plastic (GFRP) composite covers that are more than 20 percent lighter than other composite covers. SSC’s covers are also inherently non-corrosive, non-conductive and avoid problems relating to theft for their scrap value, which is an issue with metal covers. SSC covers also include additional product features, such as secure locking systems, venting, watertight sealing and color coding.