Analysing stability in historic masonry

20 February 2020

Following a recent spate of storms to hit the UK, many custodians of historic structures will likely be thinking about delicate historic masonry element they have hoping they survived unscathed.

As conservation engineers, a common question we therefore often get asked is “is this wall safe in high wind?” and the answer is often a complex one.

Historic masonry is a complex and varied material so to start to answer such a question it helps to make some assumptions. We can for example, in a simple case, assume that it has no tensile capacity and infinite compressive capacity. This greatly simplifies the problem which then becomes more akin to that of assessing a Jenga tower – simple as long as you know the precise geometry.

This is where modern surveying methods, such as point cloud lidar which we used on Cadw’s Neath Abbey, pictured, are invaluable. These produce a detailed 3D model that can be used to facilitate an accurate stability analysis and, in this case, advise the management on the wind forces that would require a response.

With over 300 National Trust properties in the UK and a staggering 3700 heritage assets, such methods are an essential part of preserving, maintaining access and in some cases, sustainably reusing such structures.

Joe Williams
Engineer