Yesterday went to Birmingham for the first time in more than a decade and passed by the Rotunda building, 22-storey 1965 Grade II-listed concrete-framed tower, which brought back some memories of me working on the projects while at Dewhurst McFarlane and Partners, so i thought i would write a few words about it before I completely forget….
The building originally designed in 1961 by James A. Roberts architects and Charles Weiss & Partners as structural engineers (who subsequently became Ernest Green & then White Young Green), comprised of office floors mostly with a rooftop restaurant (originally proposed rotating 360 degrees) and a cinema. Interesting to note that Charles Weiss was a first employer for Tim McFarlane when he just graduated. Tim told me that Charles had unusual interviewing technique…. he had to sing a song and play guitar to get the job…. Little did Charles know that Tim would later become one of the most influential engineers in the UK and decades later would come to fix his building in Birmingham.
When we went to inspect the building in the early 2001 as part of the refurbishment team comprised of Glenn Howells architects and Urban Splash, we were surprised to see existing concrete slab, spanning 9m from outer perimeter columns to the concrete core was deflecting around 100mm in the middle. Evidently, there were some issues with the structure and final design couldn’t have any imposed dead load (like screed etc), so carpets were put in directly on top of the slab! I never forget the skirting board being 100 mm deeper in the middle.
When we went into the design the brief was to use the existing structure where possible. Also the major challenge was a requirement for the new access door openings through existing concrete core for the newly formed flats. So existing concrete structure had to be thoroughly investigated.
We got hold of existing design drawing by Charles Weiss & Partners thanks to the archives and found some interesting peculiarities which helped us in site investigation and subsequent redesigning this unique structure to fit new residential use.
Concrete core samples had to be taken and tested for strength as well as ultra-sonic reinforcement mapping was carried out to establish exact positions of the rebar and it’s diameters.
Then extensive finite element analysis had to be carried out to investigate a possibility of creating new openings in the stability core to create access to new luxury apartments. Investigation into the existing concrete strength in conjunction with carbon-fiber strengthening techniques allowed us to fulfill clients brief and new openings into stability core could be installed.
In addition, new curtain wall glass facade was installed instead of old badly performing facade.
Visit Britain 2008, 5* Serviced Apartments
Built In Quality Awards 2008, Apartments Category – WInner
RIBA Housing Design Awards 2005, Featured in Exhibition of Excellence
project cost £20 m