The Santa Fe Judiciary put its new General Archive out to tender: a new building constructed inside an existing reinforced concrete structure. The tender documents required a BIM model of the entire project. The joint venture UTE PECAM–MUNDO won the contract and brought us in with construction already under way. We had to model the existing building, the new one and all the services without stopping the works.

Building inside an existing structure has a problem that drawings do not show: what was built rarely matches what was drawn. Grids, levels and sections of the original structure have to be verified before designing on top of them. If the new design rests on assumptions, the error shows up on site, when the dry-construction structure has already been ordered and the services are already hung.

So we started with what was there. On the point cloud from a laser scan survey, carried out by a specialist team, we modelled the existing conditions, and only then the full project: architecture, dry-construction structure, plumbing, electrical and HVAC services, up to LOD 350. A BIM Execution Plan set out what would be modelled, who would check it and how every query would flow. Every two weeks we met with the contractor and the Judiciary’s Architecture Office to close clashes before they reached the site. The construction documents came out of the same model.

At handover, the model was updated to as-built condition and prepared for operation and maintenance, with information on materials and equipment. The Judiciary does not just receive a set of drawings: it receives its building as a model it can use for years to come.

Has your company won a tender that requires BIM? Tell us what stage the works are at.