Der Blätterkatalog benötigt Javascript.
Bitte aktivieren Sie Javascript in Ihren Browser-Einstellungen.
The Blätterkatalog requires Javascript.
Please activate Javascript in your browser settings.
4 R E L A S T ® D E S I G N M A N U A L Jürgen Feix and Johannes Lechner in the concrete structure as shown in Figure 2 Therefore this paper investigates the use of these shea strengthening elements for concrete structures with dynamic loads such as bridges 2 Description of the post installed concrete screws Concrete screws or screw anchors are normally used as a fastening system in cracked or noncracke concrete They are installed in hammerdrilled holes The diameter of the drilled hole is given by th screwmanufacturer At the tip of the screw a thread is provided as shown in Figure 2 and Figure larger in diameter than the drilled hole The screws are driven in with a special impact driver an thus cut threads into the concrete surface of the drill hole as shown in the right image of Figure The concrete screws used have special welded marks at the cutting thread to ensure a corre interlocking connection between concrete and anchor Figure 2 Load transfer mechanisms of installed glued concrete screws on basis of As more buildings and infrastructure face deteriorating conditions innovative solutions are becoming increasingly important to tackle the complex challenges of renovation In particular the reinforcement of structures in shear and punching shear has always presented a tough challenge for structural engineers Würth s RELAST ® system provides customers with a technologically innovative resourcesaving and approved system for increasing the shear and punching shear capacity of structural elements RELAST ® consists of a concrete screw and a twocomponent injection mortar The system can be easily and efficiently installed in concrete members requiring reinforcement Structural reinforcement using RELAST ® may be needed for a variety of reasons which do not necessarily pertain to the concrete element under study Some of these reasons could be • Change in building use e g residential to office • Changes in standards • Increased loading e g increased traffic on a bridge • Aging of buildings Wear and tear • Wrong design False install tion • Corrosion Stress cracking In terms of composition RELAST ® consists of an ISO connection thread from one end and a concrete cutting thread from the other The screw comes with a pressure distribution washer that ensures an even pressure distribution on the surface of the reinforced element a wedge lock washer to stop the rotation of the nut under dynamic loading and a hexagon nut to apply the torque moment The load carrying capacity of RELAST ® is sustained primarily by the mechanical interlock that is achieved when the screw is driven in the concrete and the screw threads cut in the concrete as shown in figure 1 and secondarily by the adhesive bond of the screw to the concrete by the injection mortar The load carrying capacity is only activated after the torque moment on the hexagon nut is applied RELAST ® concrete screws are available in nominal diameters of 16 mm and 22 mm in combination to ISO threads of sizes M16 and M20 respectively Installation is very easy and convenient and can be done from only one side of an element even when the structure is under operation The screws are made from carbon steel and are available in a special coating which guarantees a corrosion resistance of class C5-Imiddle according to DIN EN ISO 12944-6 Figure 1 Mechanical interlock of RELAST ® to concrete [1] 1 INTRODUCTION