Cable loops, individual and rail-mounted, have been recognized by the precast industry as an established means for uncomplicated connection of walls and colunmns for many years and are suitable for creating structural connections or for transmitting static forces. Philipp, as one of the leading manufacturers of such systems, has now extended its Power Duo Rail more customer-oriented.
Until now, only a combination of mortar and rail for effectively connecting two concrete elements was possible. With the new approval, Philipp has now added Grace Bauprodukte GmbH, Essen, Germany, as a second mortar supplier. This opens up more possibilities for construction contractors for using a suitable or preferred mortar. No matter whether P&T or Grace are chosen as possible mortar suppliers, a liquid grouting mortar and a thixotropic mortar is in each case available.
Increasing the design forces
In this connection, higher design forces for shear forces running parallel to the joint could be achieved with the Betec mortars from Grace. Here, the 90 kN/m attained with the grouting mortar and the 70 kN/m attained with the thixotropic mortar set new standards, resulting in an increase of 10 % and 30 %, respectively.
For use of the Power Duo Rail, the direction of installation is predefined and clearly marked in order to achieve optimal load transfer. Where this requirement was nonetheless ignored, a structural analyses used to be difficult to provide. With the new approval, checked, practice-oriented design forces are now available that enable error- tolerant installation.
Maximum faulty position can be calculated
Where vertical lappings of the cable loops do not meet the requirements of the approval (≤ 3 cm), this could previously not be shown in the design calculation. With the new approval, the maximum faulty position of 12.5 cm (half the distance of the cable loops) has now been verified and filed. The safety level achieved is nearly the same as that of correctly installed reference products, although the design values are lower by around 30 % compared to the normal values.
These new extensions make the Power Duo System much more transparent and thus easier to master and calculate for planners/certified structural engineers. A revised version of the online design aid is available on the Philipp Website as support. Only a few entries are required for quick calculation and verifiable results.