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Damage to Tensioned Rope Systems

Now and then one finds damaged tension ropes on greenings. Usually it is the mounts that are affected, which may be bent or torn off the wall at the highest point of the flexural buckling load. This might be due to errors during assembly (poor mounting), but unfortunately, the problem often lies in the planning, or even in the design/construction of the mounts, attributable to the respective manufacturer. As a result of slow plant growth, such problems usually do not occur until the warranty period has been exceeded. Here you can learn about damage patterns, explanations of their causes, and how FassadenGrün prevents damage to its own products. 

Damage to cables and mounts caused by excessive weight

Rust Damage

Some tensioning rope/cable systems are only zinc-coated (galvanised) and rather designed for indoor use: Mounted outside, they soon rust. Such elements are hardly qualified for facade greening. But stainless steel mounts too can rust; for instance, in the case of curtain systems. Oftentimes, discolourations occur because the respective stainless steel is not sufficiently rust-proof for outdoor use. 

Impracticable Tension Rope Systems

If curtain systems (for example) are used, which are designed for light loads only, structural damage is inevitable. Due to the heavy loads in wall greening caused by storms, wet leaves, fruits and so forth, the mounts will soon be torn out. Even mounts which are actually designed for metal bars will give out when clamping rope, because the tension is much higher using ropes instead of bars. Vandalism damage, in turn, occurs when improperly planned (horizontal) tension ropes give a "climbing possibility" for a vandal.

Inadequate Coordination/Harmonization of Plants and Climbing System

In the case of climbing systems, it is necessary to address their suitability with certain plants. FassadenGrün-systems are divided into five construction styles. With the help of the climbing plants pages on this site, an assignment to particular construction styles is possible. This prevents overloading.

Wrong Climbing Technique

As a rule, tightly tensioned ropes/cables should not be overgrown with and thus "strangled" by climbing plants. Otherwise, the resulting tensile stresses of up to 500 kilograms (3 mm rope) or 1,000 kilograms (4 mm rope) will destroy the mounts. FassadenGrün addresses the difficulty of finding the right climbing technique-- i.e "parallel rooting" / "stock arrangement" in the case of vulnerable/tempermental climbers and strong twiners (Chinese wisteria, bittersweet, knotweed). Please have a look at the respective pages on climbing plants. 

Forced Transfer of Load Peaks

Span wires are multilaterally loaded. This starts with the pre-stress, later it is the load of the leaves, fruits, and stems which can reach 10 kilogramme per square metre and even double in case of wet leaves (after rain). Extreme loads of 50 kg/sq emerge from icing, from multiple glazes and wind pressure, especially in great heights and on corners of buildings. Many providers of span wires fasten the cables in such a way that in the case of load peaks (storm, icing, climbing, rebounding children’s balls, or the like) the abrupt, quite high tensions are transmitted into the brackets, compulsorily. If these brackets are rigid and do not "spring", they cannot hold the loads and are torn off, soon. Brackets from FassadenGrün are only slightly tightened by hand (without cable tensioner) and thus, are designed not totally rigid but slightly springy. All cross holders are equipped with an anti-slip protection, which means overloading is not completely, but only partially transmitted onto the brackets. The cables slip out slightly and can be tightened again.

Broad Wall Spacing

Broad wall spacing operates like a lever and generates a high flexing buckling-load, which can bend or tear off the bracket. FassadenGrün states exactly, which bracket is maximally suitable for a certain wall spacing.

Insufficient Fastening

These various problems can occur: The emerging tensile stresses in a tensioned rope are underestimated, or not taken seriously; the shafts are disconnected or tapered in the diameter, in the area of the highest flexing buckling-load, at the transition into the wall bend. Or the fastening in the wall is not sufficiently placed. Brackets from FassadenGrün do not have a shank disconnection, or tapering. With the help of strong plugs they will be deeply and safely fastened in the wall.

 

 

Impracticable (curtain) system, torn off mount with rust marks.
Climbing Plant Support System -- Damage
Unsuitable eye bolts / plugs and too much wall distance, which causes the eye bolt in the lower, heavily loaded part to be pulled out.
Structure eyelets
Too much wall distance, hooks are not screwed deep enough into the dowels.
Too much wall clearance with a mount
Vandalism: In public spaces, ropes/cables should not be mounted horizontally up to a height of about 2 m, due to the "climbing effect" provided to possible vandals.
Wire rope damage due to vandalism
Stainless steel bracket with a from inside rusting (zinc-coated) metal plug: The problem here lies in the damaged coping, which leads water into the wall. This water drenches the wall and causes corrosion on the originally dry plug.
Climbing plant support system with rust
A wall bracket which was designed for bars, not for cable and is now loosened due to a risky greening (Chinese wisteria).
Wall mount: loosened anchoring on wall console
Corrosion of a zinc-coated metal plug caused by a non existing sealing of the drill hole, fraying of the bracket due to a compulsive transmission of load peaks
Corroded metal dowel
Corrosion on a zinc-coated wall bracket
Corrosion on zinc-coat
Too much wall spacing, too weakly dimensioned bracket.
Planning error
Overgrown by silver fleece vine and overwrought cables, overloaded brackets
Damaged wire rope
Cross bars in the lower area of a growth support might occasionally invite climbers and slacken, or bent like in the case of these climbing bars.
Base area
Spanned wire with broad wall spacing, forced transmission of load peaks.
Wire rope defect
Insufficient co-ordination of plant and climbing system, as well as wrong climbing technique
Damaged cable
Pulled out bracket caused by the wrong climbing technique (entwinement by Wisteria)
Damaged wall mount