Phased demolition and construction scaffold
A phased scaffold was required on Princess Way and St Mary’s Street to aid the partial demolition of the existing building before being adapted to assist the construction and new façade installation. To keep the changes between phases minimal, Enigma engineers and operatives working onsite consulted with Morganstone representatives to discuss building offsets and space limitations. The scaffold configuration design for the demolition phase was then revised so that the outer scaffold upright would become the inner upright for the construction and façade installation phase. This solution was also more sustainable as it significantly reduced erection and dismantle times and the amount of scaffold material delivered to site.
After a structural engineer conducted a preliminary site visit, it highlighted the need for extensive propping to aid the demolition works by helping to stabilise the building and provide structural support.
Based on the engineer’s report findings, Enigma’s Design team overcame the challenge and provided an initial design proposal within a few days. The proposed solution was then further adapted after liaising with the client and on-site team about their specific requirements and site constraints. This demonstrates our ability to respond quickly to project changes and efficiently provide a revised solution without compromising quality.
The structural engineer’s report identified high reaction loads of up to 1200 kN in places throughout the building. So Enigma transferred the loads from the top floor down to the foundations by erecting a bespoke birdcage propping scaffold. Also, to ensure the scaffolding could safely withstand the exerted loads, the biggest axial loadings were calculated and checked against the allowable loads of the scaffold uprights.
Careful consideration and planning were needed to spread the axial loads via sole board details. Notional horizontal loads were calculated against bracing patterns and jacking details to ensure the overall structural integrity of the scaffold. Also, all the mentioned solutions above were clearly illustrated in standard details included on the design to provide Enigma operatives erecting the scaffold on-site with safe tolerances.
Later in the project timeline, the suitability of the permanent structures’ floor slabs to support the additional mechanical loadings from the required plant and machinery was in doubt. So Enigma engineers evaluated the potential problem by calculating the most excessive loads exerted throughout areas of the building. Based on the study data, the propping designs were updated to ensure the continued structural integrity of the scaffold structure and the encompassing concrete frame.