Foundation Reuse and Strengthening Works at 65 and 67-69 Whitfield Street, LondonÂ-PPT Presentation

PPT Presentation

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The Fitzrovia redevelopment at 65 and 67–69 Whitfield Street retained and adapted existing buildings for residential use, while replacing the roofs and adding new structure. Rather than demolish and rebuild, the project reused and strengthened the existing foundations.<br /><br />The team followed established foundation-reuse guidance, using an early, risk-based process. Because desk research provided little reliable information about the foundations, decisions relied on site investigations and the buildings’ “existing realistic loads”—the maximum loads they had already carried. The investigation and assessment approach was agreed with the client, Building Control and the client’s insurers. Risks were assessed foundation by foundation, with construction monitoring used to manage residual uncertainty.<br /><br />At 65 Whitfield Street, investigations found short, variable-length piles of uncertain capacity. New loads therefore required strengthening: collars around existing pile caps and transfer beams connected to columns transfer additional load to new mini-piles. The new piles were designed with defined factors of safety.<br /><br />At 67–69 Whitfield Street, pad foundations generally performed adequately. Where increased loads warranted further assessment, analyses found the concrete sufficient and predicted settlements small. The design sought to balance loads against the buildings’ proven existing capacity wherever possible.<br /><br />The project’s success depended on close collaboration between the client, geotechnical and structural engineers, early intrusive investigations, careful risk allocation and detailed monitoring during construction. Reusing the foundations and buildings preserved valued structures, met planning requirements and delivered significant carbon savings. Despite the challenges posed by limited information and older construction methods, the team developed a successful, tailored reuse and strengthening strategy.

Keywords

Fitzrovia redevelopment

Whitfield Street

foundation reuse

adaptive reuse

residential conversion

structural strengthening

mini-piles

geotechnical engineering

building retention

carbon savings