Chichester Free School, Chichester, London

Doran Consulting was appointed to provide civil and structural engineering design services for this new school on the site of a listed convent building.

The convent was refurbished to form new secondary and primary wings constructed to either side of the existing building in order to provide improved educational facilities for 1,280 pupils.  The contract also included the provision of multi-use games facilities and external landscaping.

The new steel framed facilities are designed to replicate the steep roof pitches of the existing building and varying floor to floor levels required several ramps to tie the existing levels into the new buildings floor levels.

Contiguous Flight Auger piles were used to support the reinforced concrete ground beam foundations.  The high water table around the site provided challenges in both the civil and structural design.  The lack of connectivity to the local foul and storm drainage systems required the civil design to incorporate a private foul treatment works and an innovative storm infiltration design applying a full site wide SUDS strategy.


The use of BIM within a Common Data Environment (Aconex) allowed the design team to integrate a digital survey of the existing convent building into the 3D models for the refurbishment to the existing and the extension of the two new school wings. This was vital in designing the new structure around the existing building, avoiding site clashes and to deal with complex details connecting the old building with the new, well in advance of site construction.

All primary designers produced information in a 3D environment using Autodesk REVIT. The combined models (federated model) allowed coordination between disciplines, identification of problems, and allowed resolution before reaching site. Early clash detection was vital in helping the project to run smoothly with weekly reports issued to all design team members.

The design team were able to export 3D information directly to subcontractors, such as the steelwork fabricators. This exchange of models helped in the production of more accurate quotes and fabrication models, and also vastly reduced dimensional and other RFI’s between designers and subcontractors. The model interchange facilitated fabrication information that could be more readily checked by the design team as part of the overall due diligence process.

Throughout, our Clients were able to visualise the works at an early stage in a ‘virtual environment’ affording them the opportunity to review design intent and to analyse various design variation alternatives. We assisted with the production of construction sequencing animation, 3D walkthroughs and high resolution visuals using a combination of Infraworks, Revit, Navisworks, Lumion & Photoshop. These deliverables were subsequently used by the client in developing a greater understanding of the engineering works, for engaging with the public and in the production of widespread marketing materials. The final federated model was provided to the Client as a BIM model to BIM maturity level 2.