architectural membrane association
The concentration of loads in a corner area of membrane structures leads to the use of corner plates subsituting the membrane in areas of high stresses. A steel plate plate reinforces the corner of the membrane structure and transfers the membrane forces into the primary construction. Both membrane and edge ropes are connected to the corner plate, an outer rope connects to the primary construction. In small-scale membrane structures with low loads, the membrane can be carried out into the corner tip and is just reinforced by belts – in this case the use of a corner plate is omitted.
The overall shape of the corner plate is following the membrane shape - typically a triangular geometry. The plate needs to fix membrane, membrane edge elements like cables or belts as well as the outer cable on quite limited space to create a compact detail.
The membrane must be connected to the corner plate in order to prevent the membrane from slipping along the edge cables, losing tension and forming folds. This is mostly realized by fixing the corner of the membrane with a clamping bar fitting to the shape of the corner plate. The corner of the membrane is mostly doubled by welding an additional layer on top of the surface in order to handle the stress peaks.
The edge cable or edge belt needs to be connected to the corner plate in order to allow that forces of the membrane that flow into the boundary elements are transfered into the corner plate. In case of cables this is realized by tubes welded at both edges of the plate. The cables can be plugged into these tubes and fixed with nuts. In case of the use of belts, corresponding slots in the corner plate must allow the attachment.
Thumb rule for the correct placement of the hole to accommodate the outer rope is a distance of the corner plate edge to the center of the hole of about 3,2 times the hole radius.
Mostly corner plates are made out of galvanized steel. Stainless Steel is another option but quite sensitive to mechanical injuries during the installation phase. In any case, installation must be carried out with utmost caution.
It is advisable forseeing anchoring points at the corner plate for attaching devices to apply pre-tension into the membrane during installation. This can be a simple additional hole in the corner plate which allows the fixation of a ring screw for example where belts can be inserted for pulling the structure into final position.
It is important to round off all edges of the corner plate to avoid any injuries when handling the detail.