Making an Irish Free State City – Repairing under Patrick’s St

On 26 October 1926, a small crowd gathered around an open manhole on St Patrick’s Street. They were surprised when two individuals, clad in thick rubber suits and covered in mud, emerged. Philip Monahan, City Commissioner and Stephen W Farrington, Corporation of Cork City Engineer, appeared at the top of the ladder.

The following day, the Cork Examiner reported that both individuals had descended to inspect the arch, or culvert, beneath St Patrick’s Street. This structure supported the street above a winding river channel that frequently flooded nearby streets during high tides. Officials were concerned that increasingly heavy traffic was placing severe strain on supports never designed to bear such loads.

The arch or series of connected culverts were part of a late eighteenth century construction over some of the city’s canals. It was an impressive feat of engineering, which led to the creation of the city’s main streets.

The drawings and maps and paperwork on the filling in of the water channels have been lost to time. However, there are nods through antiquarian books in the nineteenth century that flooding and in particular sewage control problems led to an engineering solution of fully arching over many of the canals.

From the early 1920s minute books of the Corporation of Cork and typed up minutes in the Cork Examiner give insights into the arch on St Patrick’s Street and some of its origins.

It was built as a continuous culvert in the late eighteenth century from west to east through the centre of the city centre. It had its beginning at the foot of the Mardyke stream, from where it ran into Sheares Street, then through Liberty Street, and onto Daunt’s Square. From this latter place the culvert was carried down what is known as the northern side of St Patrick’s Street, until it reached Messrs Cash’s corner. It then swung out into the middle of the street, after which it came back to the side again. It progressed under the Fr Mathew Statue to the downstream side of St Patrick’s Bridge, where it joined the river through an output. This arched output area can still be seen at low tide next to the bridge.

The span of the continuous arch was approximately 16 feet and it varied in height from as little as two feet in some places to as much as eight feet in height in others. The greatest height occurred at the St Patrick’s Bridge end and under Daunt’s Square.

In the early twentieth century some adequate steps were taken by the corporation to prevent any danger of collapse by promptly attending to subsidence. Repairs were of a temporary nature, and when Philp Monahan became City Commissioner in 1924, it was the one issue that the local press asked him about.

For many years, the St Patrick’s Street arch had been constantly under supervision, and any noticeable weaknesses had been attended to. However, the time had come when radical reconstruction would be more economical than continual maintenance.

Similar arches existed in Sheares Street, Cornmarket Street, Grand Parade, South Mall, Parnell Place and South Main Street. A portion of the archway under the latter street was dealt with in 1927. Cornmarket Street and Washington Street were in a better a condition than the St Patrick’s Street arch. The South Mall and Parnell Place were not accessible for internal examination, but there was no external indication warranting immediate action.

Sanction was obtained by Philip Monahan, City Commissioner, from the Local Government Department for the borrowing of the necessary funds of £20,000 for the arch under St Patrick’s Street. In the funding application £2,000 was also raised for the reconstruction of Carroll’s Bridge on Camden Quay, which had been closed to heavy traffic for some time.

Work commenced in April 1928 on the reconstruction of the arch. The scheme, which was under the direction of City Engineer Stephen Farrington was a year-long project and by the start of the project the estimated cost had increased to £22,500. The scheme embraced a stretch of 1,500 feet of St Patrick’s Street.

The Cork Examiner on 21 April 1928 details that in place or the old system of arches, the aim of the scheme was to construct a “cement culvert throughout the whole underground channel, which would form a sound foundation for the heaviest traffic and the massive buildings in the principal streets”.

The new work comprised of a “concrete culvert 42 inches high internally, 28 inches wide, and roughly egg-shaped in section”. This section combined the advantages of a “large pipe to carry off the storm water with a narrow invert to concentrate the sewage in dry weather”.

Where the work was being carried on underground, the culvert would be of specially-shaped concrete blocks, which had all already been prepared by corporation workers for the purpose. Approximately 3,000 blocks in all would be used. The culvert would be altogether composed of local material except the cement. The new sewer would be able to carry away sewage more cleanly and rapidly than the existing stream-bed. Access manholes were also to be fixed at intervals of about 200 feet.

The progress of the scheme was slowed down by the fact that work could only be carried on by small gangs of workers at low tide. Employment also entailed a night shift in addition to the day workers. There were two five-hour shifts in the twenty-four hours. When the work was in full swing, there would be extra employment.

The Cork Examiner continued to detail that engineering challenges also existed as the existing historic arch averaged about 16ft in width. It was constructed undressed from which all the cementing material had washed away. Many of the arches were very much depressed in the crown having from time to time to be supported with timber to prevent collapse.

The Cork Examiner noted of the challenge of potential collapse: “The timber was one of the principal difficulties in carrying out the work, as it occupied the space where the new archway was to be erected, and the timber could not be removed without special precautions, owing to the danger of subsidence. Where the timber was very closely packed the work would have to be done in open cutting, that was by making a trench from the surface down.”