The Landsby Building (Plot NW07/08) forms part of the Wembley Park Masterplan which covers an 85 acre site around Wembley Stadium in north west London. The site is being developed by Quintain, who we have previously worked with on Plots W01, W04 and NW06, and are currently working with them on Plot NW09/10.
Plot NW07/08 is a mixed-use development and provides 362 residential units across two separate blocks of 17 and 15-storeys, with retail space at ground floor and a basement car park. The plot is located to the north east of Brent Civic Centre facing onto Olympic Way. The structure is a reinforced concrete (RC) frame, with flat slabs and blade columns typically located within the internal and external walls. The stability of the frame is provided by the stair and lift cores, with discrete shear walls to limit sway deflections. The building is supported on piled foundations, with individual pile caps supporting the basement and ground floor slab. The basement is formed using permanent steel sheet piles, which are set back from the façade above to allow the perimeter columns to be supported on discrete pile caps at basement level. The sheet piles have fully welded clutches and are designed to achieve a Grade 2 environment. For the basement car park and back of house areas, the sheet pile is painted and left exposed.
One of the key drivers for both the client and the design team was to reduce the use of transfer structures. This required a significant amount of co-ordination between the different disciplines to try and align vertical structure through the building. The co-ordination process was particularly difficult as the use of the space at basement level consisted of a large car park, which did not line through with the proposed room layouts above. Through a collaborative design process we were able to minimise the amount of transfer structure, limiting it to discrete RC transfer beams above the car park circulation zone. From a structural perspective, we were able to provide the Architect with some flexibility in changing layouts between floors, by allowing certain columns to be rotated by 90 degrees. In order to achieve this, we typically provided column heads to transfer the loads between columns.
The vertical circulation strategy through the building was to provide the stair and lift cores on opposite sides of the corridor. The servicing strategy for the building used the corridor to distribute services, which prohibited the use of RC linking beams between the stair and lift cores. Due to the aspect ratio and height of the buildings, there was insufficient stiffness in the separate cores to resist the lateral loads applied to the building in this direction. Our solution was to incorporate ‘wing walls’ extending from both the stair and lift core to increase the stiffness of the building in this direction. These were located within internal partition walls, to avoid impacting on the internal layouts.
The project incorporated several innovative construction techniques to provide programme benefits and reduce health and safety risks on site, including precast concrete columns and walls. The contractor proposed the use of precast edge beams to allow safer installation of the edge protection, which we implemented as part of the structural design. The slab reinforcement was designed to allow for the use of spin mat, which uses pre-fabricated mats that can be rolled out on site, which reduce on site labour and potential workmanship errors.