Added: 26th July 2021 by CampbellReith
Very few secondary school projects include the design of bridges, reinforced earth embankments and Vierendeel girders, but CampbellReith is delighted to be involved in one. Dover Grammar School for Boys is a new build secondary school located at the top of a steeply sloping site within Dover. CampbellReith’s multi-disciplinary team is delivering the civil, structural, geotechnical and geo-environmental design works for Kier Construction to provide a new £22m facility for the schools 860 11 to 18 year old pupils.
The new school building includes a sports hall, activity studio, sixth form centre, ICT business suite, drama studio and a large main hall.
Due to the sloping nature of the site, access into the second floor reception area is gained via a footbridge from the new landscaped entrance plaza. The bridge spans 23m from a bankseat to the new building and comprises steel Vierendeel girders and a concrete deck.
The change in level is one of the key challenges on the site. To deal with this, the new school site has been divided into three main plateaus; a new car park/entrance area, the school building itself and a lower tier playing field. The transition slopes between these areas include sensitive chalk slopes which have been stabilised using a combination of soil nailing techniques, gabion retaining walls, earth reinforcement and contiguous piled walls. Campbellreith’s in-house geotechnical team have designed and detailed an 11m high geogrid reinforced earth retaining wall between the middle and lower tiers to preserve the integrity of the chalk slope. Extensive 3D modelling was undertaken at scheme stage to determine the cut and fill volumes and the most economic layout for the new buildings and landscape areas.
To enable future flexibility to be incorporated into the floor layouts, the structural frame accommodates long spans to provide the clear open spaces required. A storey height steel Vierendeel girder spans over the ICT/Business Suite, achieving a clear span of 12m whilst supporting the loads from the drama studio and entrance foyer above.
Sustainable drainage (SuDS) techniques have been adopted for the site to comply with the requirements of the statutory authorities. The detailed Flood Risk Assessment produced by CampbellReith’s in-house team informed the drainage strategy for the site which included attenuation features that discharge surface water into the ground using geo-cellular soakaways, porous paving and tree pits. The new multi-use games areas (MUGA’s) and sports pitches have also been used to minimise the volume of surface water runoff from the site by incorporating porous surfacing and sub-base attenuation/infiltration into the design.