Client
RG Group
Architect
Cunniff Design
Completion
September 2017
Value
£23m
Project Summary & Objective
Crown House is a prestigious student accommodation scheme located in the heart of Sheffield city centre providing 355 studio bedrooms across three blocks, ranging from six to nine storeys. On the ground floor there is a large amenity space and an outside courtyard accessible for residents only.
The Client’s objective was to transform the former office block into luxury student accommodation by adding three storeys to the existing frame and build two new blocks at the rear of the property.
Key Challenges
One of the key challenges that Apex Consulting faced on the project was how to successfully extend the frame of the existing building by three storeys. In order to do this, the team needed to carry out a detailed load assessment to determine what extra load the existing steel frame could carry.
The addition of the two new blocks at the rear of the building posed their own challenge as there was a part constructed basement that required partial demolition. However, the topography of the site required the existing wall to remain in an unpropped condition during the construction.
Careful consideration to the practical construction of the two new buildings had to be given as the courtyard would become fully enclosed upon completion of the buildings.
Other challenges included the existing substation on the site as it was required to be kept in operation, but new foundations were required to be constructed around it at a lower level. There was also a live sewer from adjoining properties across the site and negotiations with Yorkshire Water were needed so that the sewer could be relocated under a build close agreement.
Solution
To add the required three storeys to the existing frame, Apex Consulting located the historic drawings to complete a detailed analysis of the frame and the live load of the office space verses the proposed residential nature to be assessed. In conclusion, the team decided that three storeys could be added to the frame. The foundation loads were also assessed on this basis for the building before and after the extension.
A propping scheme and safe sequence of works was designed and agreed for the retaining wall on the site by using detailed survey information and liaising directly with the contractor and understanding the build sequence.
The new buildings at the rear were formed in reinforced concrete and the successful agreement of the build near, and relocation for, the sewer was approved.