Conservation compendium. Part 8: Bond timbers in old brickwork

This article suggests ways in which readily available technology (a smartphone or tablet) can provide engineers and construction professionals with a simple tool to test vibrations. This is demonstrated on the new feature staircase (a lightweight and unusual structure) at the Institution's HQ in London. A free-to-download vibration testing app (beta version) has been developed by Expedition, and is introduced here.

Post-tensioned (PT) concrete floors are now widely used in the UK, particularly for high-rise buildings. This article provides information on how to scheme a PT slab and how the use of post-tensioning affects the rest of the structure. A more detailed guide to the design of PT floors can be found in The Concrete Society's Technical Report 43 (TR43): Post-tensioned concrete floors: Design handbook.

Historic buildings and structures, like any other, move to some degree, whether due to thermal effects, changes in moisture levels in the structural fabric, influences on the founding subsoil, or environmental forces. The key question for the conservation engineer is to determine whether the movement is progressive and presents a risk to the structure. This article introduces engineers to the various techniques available to monitor movement in historic structures, from simple manual techniques which are less commonly used today, to sophisticated electronic systems. The form of monitoring will depend on the nature of the assumed movement, the funds available, and the possible consequences if the movement is progressive.