The Four Courts, Dublin – Innovative Monitoring and Long Term Repair Techniques

The Four Courts, Ireland’s main courts building, is situated adjacent to Dublin’s River Liffey and was built between 1776 and 1796 making parts of the structure well over 200 years old. During the 1922 civil war, a large... [ view full abstract ]

The Four Courts, Ireland’s main courts building, is situated adjacent to Dublin’s River Liffey and was built between 1776 and 1796 making parts of the structure well over 200 years old. During the 1922 civil war, a large proportion of the dome and drum of the structure suffered extensive damage as a result of bombardment and fire. The dome, formerly constructed of timber, was rebuilt in reinforced concrete at the end of the 1920s. Some 85 years later, this iconic building is showing its age with the early onset of reinforcement corrosion and the continued deterioration of stonework. An innovative combination of testing, structural health monitoring and repair design were required to restore the structure’s integrity, whilst minimising disruption to allow the courts to function unhindered. Inspection and Non-Destructive Testing (NDT) was undertaken to determine the nature, source, extent and significance of observed deterioration. The use of a cutting-edge, magnetic field, remote, crack monitoring system also provided insight into the movement of structural cracks. Analysis of the combined results including Finite Element Analysis (FEA) modelling gave a holistic view of the nature of deterioration within the structure. This allowed for bespoke remedial works to be designed including: two access scaffolds; a cathodic protection installation; and a composite Polyparaphenylene Benzobisoxazole (P.B.O) and mortar mesh strengthening system. This paper will look at the various aspects of the structural investigation and analysis and describe in more detail the remedial works proposed.