Benefits or achievements
It was a steep BIM learning curve from the outset, balancing the various BIM maturity levels of team members, while minimising adverse impact. However, the partnering ethos of the PPC2000 contract lent itself to the adoption of BIM –adapting existing processes to place BIM at the core: learning to apply, do, review, innovate and re-apply; and revising working practices to create efficient issue resolution and processes.
A BIM Execution Plan (BEP) was developed from scratch, detailing the efficient use of compatible, cross-discipline federated models with comprehensive data, clash detection, and defining the procedure for model exchange.
The Interserve team used a virtual walk-through and tagging process to review live design issues which proved more efficient than automated clash detection. 4Projects 3G provided a secure collaborative platform to exchange/share 3D model information.
The 3D model allowed non-technical personnel to understand and contribute to the scheme early in the process. This drove operational FF&E cost/time efficiencies and supported the preparation of new operational staffing regimes – achieving cost savings of £850k.
The Ministry of Justice set a target of 10% cost savings between selection of Interserve and commencement on site. Taking into account value indicators of similar projects, cost savings achieved (as analysed by the client and cost consultant Sweett Group) show a cost saving of 20% from the rate of £2,910 per square metre anticipated for a comparable project and the rate of £2,332 per square metre achieved in relation to Cookham Wood by the time of establishing the agreed maximum price.
These savings have been achieved through the following means:
Joint working by Interserve with Tier 2 subcontractors in developing innovative proposals at the point of selection
Further joint working by Interserve and its Tier 2 subcontractors with the client and its
consultants throughout the contractual preconstruction appointment
Additional information provided at the point of selection and throughout the preconstruction phase through the use of BIM.
BIM delivered project design co-ordination improvements resulting in: reduced risk and increased certainty of outcomes; improved clarity of design; streamlined construction; and transparent end-user operation. Increased design confidence, enabled the team to fully exploit design for off-site manufacturing.
The houseblock cell pods were formed as three-sided boxes, resulting in a reduced building footprint, while BIM ensured the pods were manufactured to the correct dimensions and specification. A subsequent establishment report records fewer defects than expected for this type of scheme. Off-site manufacturing delivered a £26k saving, against an allowance of £36k. The design resulted in a reduced programme of 44 weeks – delivering time and overhead savings.
The incorporation of BIM, alongside other initiatives, contributed to savings made at HMYOI Cookham Wood, which when benchmarked was approximately 20% of the total build cost.
Cookham Wood’s impact reverberates throughout the industry. Our team sought to identify lessons learnt from the outset and this continued throughout the project – changing the way in which some deliverables were approached and provided live feedback to the industry. These have provided some of the foundations for the development of PAS 1192-2:2013, which informs best practice guidelines used by the industry today.