Innovations in transport anchor systems are rather rare, because such systems with threaded sleeves or spherical balls – e.g., as hole anchor systems or wire-rope lifting loops – have been long established with designers and manufacturing precast plants and can no longer be imagined without for building with reinforced-concrete elements. These products, with their perfectly matching system components and with their high quality and safety standard perfectly cover the wide-ranging application possibilities.
There nevertheless remains sufficient room for new transport anchor types with characteristics that open up new applications and/or improve existing practices. Towards that end, the company Philipp has combined the extensive knowhow gained from joining technology with the mechanisms of transport anchors. The result of this effort is the wire-rope lifting box (see Fig. 1): a flexible rope loop that is folded out from one side of a securing box, with all the advantages of a wire-rope lifting loop (see Fig. 2). This results in an even higher-performing and yet more economical anchor that enables direct fixing without lifting tackle. This also does away with the widely unpopular collecting and returning of lifters and the resulting often necessary checking for an end to service life of the equipment that this involves. On the other hand, the open flexible end-anchorage of the rope loop offers great room for adjusting to complex geometric conditions and/or existing reinforcement layouts – in particular for concrete precast diaphragm beams.
Flexible end-anchorage in reinforced-concrete wall elements
The completely galvanized wire-loop lifting box consists of an ordinary sheet-metal box and the rope loop attached inside, which is directly installed by nailing – or by gluing to the formwork, in the latter case without penetrating it. For lifting and/or installation processes of precast elements, the rope loop is simply folded out of the box installed up to a maximum diagonal pull of 30 °, and always without special lifting tackle – i.e., without direct suspending slinging hooks or shackles. The wire loop lifting box starts with the load class 4.0 tons, which can be used unproblematically for many small to medium-sized elements (up to a total weight of approx. 6.2 / 5.4 tons axial pull / 30° diagonal pull) beginning with a minimum thickness of 15 cm.
The particular strength of the DAHB lies in the flexible end-anchorage in the reinforced-concrete wall element. The DAHB is a highly practical solution, especially for precast elements with many and/or large openings and with therefore only few possibilities for installing transport anchors. Whereas direct, long anchorage is the decisive plus in slender web areas, the simple bent ropes demonstrate their strength around narrow lintels. Considering the existing reinforcement that must only be slightlysupplemented, transport solutions in highly fragile areas of construction elements are therefore possible, which, based on comprehensive test programs, are now implemented in a standardized application (see Fig. 3).
The advantages of the wire-rope lifting box are therefore, first, the unbeatable price-performance ratio and, second, the simple and time-saving handling as well as special application in narrow areas of construction elements. Work on further ideas such as magnetic mounting is already being planned so that there is now nothing in the way of a long success story of the wire-rope lifting box.