Load-bearing floor doubled in two months time

Anchors with a wide range of applications

"It's a great example of what you can do with the system," says Jacco Verhage, Project Engineer at Vogel Concrete Maintenance. The company recently made a floor of an industrial building suitable for a new function with heavier loads in a relatively short period of time. "With 288 Relast anchors from Würth and 2,000 meters of carbon adhesive reinforcement, the load capacity of 700 m2 of floor was doubled in two months."

The building is located in Nieuwerkerk aan den IJssel in a business park on the A20 motorway. The owner had the premises with hall and offices remodeled and expanded for a new tenant. Verhage: "The office part moved to the front. It was first at the back and that was the scope of our work. In fact, at a late stage it turned out that the floor was not suitable for the storage function that was envisioned. It was once built for 500 kg/m2, while 1,000 kg/m2 is the new requirement."

According to the structural engineer, the first floor, consisting of hollow-core slabs with a structural compression layer on primary beams, had insufficient transverse force capacity. Verhage: "ABT had little confidence in traditional solutions such as drilling in and gluing threaded studs, because that would have required a lot of threaded studs. We then contacted Würth and proposed its Relast system to increase the transverse force capacity, in combination with carbon glue strips for moment reinforcement. The client agreed and thus 288 anchors were installed, distributed over twelve beams supporting 700 m2 of floor. The floor and beams were further reinforced with carbon adhesive reinforcement."

Transverse force reinforcement pierced 

Jurgen Verhoeven, technical advisor for Würth, is pleased with this successful application of the Relast anchors. "It is the third project in the Netherlands where this system has been applied (all carried out by Vogel) and the first time in combination with adhesive reinforcement. Relast was introduced to the Dutch market at the end of 2019 after a long period of product development, testing and pilots. The first project was an old concrete structure in the petrochemical industry that was reinforced, the second concerns a new construction project with apartments. There, penetrations had been drilled into foundation beams and the shear force reinforcement was found to have been punctured. The contractor was already installing the hollow-core slabs of the first floor. Vogel Betononderhoud, in consultation with the structural engineer, therefore made constructive calculations in three weeks with Relast as the solution. It then proceeded directly to execution and installed the Relast system, so that construction was not delayed. The speed is possible because the system is based on Eurocode 2 Design and Calculation of Concrete Structures, making it easy for structural engineers to calculate." 

Simple

Relast, as a system, is fairly easy to apply, according to Verhage. "Drilling stepped holes between the reinforcement usually takes the most time, especially if you want to reinforce beams from the underside. For that, we usually hire a professional drilling company. We then insert the special injection mortar and can immediately use a cordless impact screwdriver to screw in the Relast anchor, which cuts its own thread in the concrete. The mortar is the seal of the drill hole and provides some load absorption. Then pressure distribution ring, lock washer and hex nut on it, torque it and you're done."

Versatile

The area of application for the Relast anchors is enormous, according to Verhoeven. "We are facing a major maintenance and renovation task of the concrete infrastructure in the Netherlands. Our anchors are very suitable for reinforcing not only foundations, we can also give bridges and other structures a structural upgrade. You can use them to repair missing or damaged reinforcement or adapt structures for increased traffic loads. In existing buildings, the anchors make it possible to realize another function, add an extra floor, compensate for a column relocation or increase the floor height. Or how about increasing the load-bearing capacity of floors in parking garages to create spaces for the heavier electric cars? In all these cases, the Relast reinforcement system is an excellent option."