It should be obvious from the above examples that any attempt to stabilise masonry by using steel cramps, straps or bolts has the potential to cause more damage than it prevents. There may be some disbelief that such techniques are still being applied, but some far-ranging examples are shown here.
Each buttress, to this mid-1500s building in Saxony (Figure 2.53) is different, showing forward lean to the front façade over a long period of time. This has increased the toe pressures to each pier, with a concomitant horizontal component acting on the bed joints, tending to open them. The solution has been to insert long steel straps.
The pier at the opposite end of the same building (Figure 2.54) shows how ineffective this solution is, as all three anchor stones have cracked and spalled, and the growth at a join has forced open the perpend joint, displacing the quoin.
A similar scenario is about to unfurl at this medieval Kloster (Figure 2.55), also in Saxony, a recently reversed ruin. Extensive restoration work by way of pressure grouting has been undertaken, which will be evident for a long time to come. The works have left in place iron strap ties to each of the buttress pad-stones, which will cause cracking later.
The Cornish jetty (see Figure 2.56), subject to violent storms, has been reinforced with steel straps, all of which have severely rusted and cracked the granite edge copings, in a classic counter-productive
Figure 2.53 Forward lean of masonry façade in Saxony.
measure. The extent of rust growth can be gauged by the size of the cracks in these major stones. They are currently being replaced with stainless steel. Note how the lead embedding has not relieved the rust growth stresses.
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