Cork Roof Truss Company Ltd.(CRTC)supplied a timber trussed-rafter roof, timber wind girders and all necessary fixings for the Visitor Centre at the new Cork Prison.It was part of a project to replace the Victorian prison facilities in the area. Originally designed as a steel portal roof, contractors PJ Hegarty were keen to investigate the use of timber as an alternative.The irregularly pitched hipped roof was to be supported on prefabricated concrete walls. A timber structure was designed and detailed by CTRC and comprised of 277 trusses, some with spans exceeding 18 metres.
Due to the limited fixity at the base of the prefabricated concrete walls, wind girders were required to form part of the roof structure, providing lateral restraint at wall plate level. The girders were fastened with Tapcon II concrete screws and chemical anchors,which were also supplied by CTRC.
While liaising closely with Punch Consulting, the consulting engineers for the project, CRTC’s expertise was called upon for both the design of the trusses and the wind girders, as well as for the fastening of the girders to concrete walls.The size of the roof trusses presented their own unique set of challenges from a design, manufacturing and transport perspective. The length of the wind girders meant they required fixing to intermediate masonry walls. The challenge to overcome was to place sufficient anchors to resist the horizontal forces within a relatively small area whilst maintaining the minimum bolt spacing requirements for both timber and masonry. This was achieved by using larger diameter anchors of which no test data existed for the particular density of block being used. As such, test data was extrapolated from similar smaller diameter fixings and values were agreed with the consulting engineers.
The superseded prison was originally built by the British army as barracks in 1806,which included military detention barracks. Following proclamation of the Irish Republic, the building was handed over to the Irish military in 1922,who maintained its use as a barracks. In 1972,the detention barracks was transferred to the Irish Department of Justice for use a civilian prison.
Construction of this new medium security prison began in February 2014, and opened fully in February 2016. The modern facility holds up to 275 adult male prisoners, with the buildings energy costs estimated to be 85% of that of the old prison.
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