STRUCTURAL DESIGN: Barrett Mahony Consulting Engineers, Clancy Consulting
ARCHITECT: Meropolitan Workshop
Mapleton Crescent is a 26 storey, 86 unit, residential tower located in the centre of Wandsworth, London. It was constructed for Pocket Living using off site volumetric units and will be one of the tallest modular residential blocks in Europe. The facades feature three different kinds of green pleated ceramic panel. High-quality shared amenity spaces, rooftop gardens, shared balconies and a riverside terrace will help build a community and encourage social interaction in the scheme.
The building is currently under construction and due for completion at the end of 2017.
The structural scheme consists of an insitu concrete frame up to level 2 with an insitu concrete core going up 26 floors. The remaining structure is formed using highly advanced prefabricated off site volumetric units supported by a 1.8m thick concrete transfer slab at Level 2. On a site area of only 500m2 and bounded by the River Wandle, an electrical substation and a public road, the building construction is further complicated by a large surface water overflow sewer running under the site. The sender nature, eccentric core location and triangular shape of the building presented challenging dynamic design conditions. Wind tunnel testing was utilised during the design process to determine wind forces and floor accelerations.
ANALYSIS AND MODELLING WITH AxisVM SOFTWARE
- AxixVM greatly aided the quick calculation of the structures natural frequencies, moments of inertia and modal shapes for use by the wind modelling specialists. The ability to define the floor slabs as semi rigid diaphragms allowed for increased accuracy of the modal shapes and frequencies.
- Connections between the core walls and the module units were modelled as partially fixed beam elements free in the Z direction. This allowed for the transfer of shear and axial forces from the module diaphragm slabs into the core walls without transfer of any vertical loads. The clear graphical output of the forces in the core walls allowed for easy assessment of the vertical loads paths due to lateral loads.
- The RC design module was used to design reinforcement in accordance with EC2 for the stability shear walls and RC slabs. Along the global structural model, a local model of the level 2 transfer slab was created with a more refined mesh in order to design the reinforcement.
- Axis VM was also used to analyse the core stability in the temporary state during slipform construction and to assess its adequacy to support a tower crane to be installed on top at level 25 during the project.