Warriston Road

Works involved the construction of a new 4-storey steel frame structure, with lightweight timber 5th floor to create 11 residential units with basement carpark. The steel frame is stabilised through the installation of steel flat bar cross-bracing in each direction throughout, with the top floor stabilised by timber racking panels. The ground floor is formed from a suspended ground floor slab, with intermediate floors constructed from precast floor units which are tied back to the primary steelwork with high yield reinforcing bars to reduce the risk of disproportionate collapse.

The structure is founded on steel tubular driven piles with pile caps with ground beams spanning between. One of the key aspects of this project were that the piles were set out as such to ensure that they did not compromise the integrity of an existing Scottish Water brickwork culvert which runs directly through the site, therefore the ground beams were required to be designed to span over this. Sheet piles were also installed to the rear of the site in order to retain the existing surrounding grounds after the demolition of the existing building and retaining walls. Care was taken during the course of the pile installations not to disturb or cause damage to the neighbouring properties which are in close proximity or the brickwork culvert via the implementation of a safe working buffer zone.

The existing brickwork culvert was uncovered during early site investigations and originally Scottish Water insisted that in order to be able to maintain their asset, the culvert should be diverted into the neighbouring street to avoid the requirement for building the structure over. We argued the case in this instance that the diversion of the sewer would not be reasonably practicable, given the cost of the works to divert the sewer and due to the associated hazards of having to shut the road for a duration of time for these works to be carried out. The result of a road closure to allow this work to be carried out would have resulted in emergency access being restricted throughout the course of the diversion to numerous properties given that 5 Warriston Road can only be accessed by a single carriage one way road. There were also key Health and Safety issues associated with the deep excavations required for the diversion given the 3m depth of the sewer such as excavation collapse, falling or dislodging of materials and risk of works (and the public) of falling in to the excavations. This proposal was put to Scottish Water formally with the additional support of the fact that our design would be able to ensure that the existing manholes which provide access to the culvert would be maintained allowing Scottish Water to maintain their asset as the existing situation.

Given the nature of the project, the structure was modelled three dimensionally in Revit which helped provide a clear understanding for the setting out the piles particularly in relation to the existing culvert and the proposed drainage.