This refurbishment of a dilapidated 1960s office block creates a modern, efficient and highly sustainable working environment for Hampshire City Council (HCC). It’s a stunning transformation from corridors and cellular rooms to flexible open plan space. Its success lies in the engineer’s imaginative approach to the client’s brief in reusing the existing concrete frame and managing the risks associated with it.
The car parking at podium level was removed to allow the creation of a new entrance, 200 seat auditorium, meeting rooms, café and restaurant around landscaped courtyards. The podium was originally designed for car park loading and had to be justified through surveys, material testing and non-linear finite element analysis to take double this load from the new spaces and landscaping. New pavilions were also built off this level and had to adopt the column grid beneath the podium to avoid loading the podium slab. Cladding loads were hung from these new frames, again to avoid loading the podium slab and reducing capacity for finishes and floor loads The existing frame and foundations were all justified to support the podium additions.
Natural ventilation of the building was facilitated through the construction of chimneys along the street façades, to expel air drawn through from the internal courtyard.
Retention of the existing frame saved 50% of the embodied energy normally required to construct a building and is predicted to be BREEAM ‘Excellent’. By increasing the floor area after refurbishment HCC can accommodate 500 more staff, hence reducing office space elsewhere and subsequent energy consumption.
"This project demonstrates the far-reaching contribution to energy and carbon savings structural engineers can make when preserving and revitalizing existing structures."