Session 3 - Construction and Operation

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    Consensus
    Handover Design to Contractor
  • Interference Checking - Should be fully completed prior to handover. “If you are discovering clashes on site, you have done something wrong”.
  • Design With Tolerance In Mind - It should be accepted that the BIM will not fully represent the as built state as people naturally design within tolerances. Interference checking in the design stages need to account for this.
  • Quantity Surveyors in Design Meetings - The QS’s should attend the design team meetings especially project kick-off.
  • Handover Design to Contractor
  • Earlier Project Planning - Contractors should not plan the construction of a project at handover stage.
  • Handover Design to Building Operator
  • Editable Format - Data must be handed over in editable format if this is specified by the client. It is very important that what we handover is of some use. This is because the building operator must keep this information over a long building operational life cycle.
Suggestions
Collaborative Process
  • Never Delete Something - Change It - It was suggested that a “Golden rule” is that elements must keep a truly unique identification throughout the project. This is achieved by ensuring elements in models are never deleted and replaced, but only revised. This was as it is “very important for interference checking and quantification requirements”. However it was also suggested that really quantification tools need to be more sophisticated and that it was not in fact practical to advise users not to delete elements.
  • Collaborative Process
  • Federated Model in BIM Execution Plan - BIM Execution Plan should make clear level of “completeness” to be expected in the federated model. This should state on a project specific basis what information will be modelled and what suppliers are participating.
  • Size of Federated Model - It was suggested that model size would naturally be an issue with federated models. It was suggested that the IFC or Autodesk Navisworks format should be utilised for this process and not authoring packages like Graphisoft ArchiCAD or Autodesk Revit. It was suggested this would also resolve the issue of accessibility.
  • Handover Design to Contractor
  • Clean Model - It was suggested that there needs to be a clean-up process including removal for example of demolished objects.
  • Need To Establish Bi-Directional Link Between Contractors and Design - It was suggested that it would be very useful, in order to achieve an as-built if process could be established were the contractor could effectively issue changes to the federated design model in order that we can handover a more useful BIM at the end of the design and build.
  • Health and Safety Data - It was suggested that elements should have H&S warnings attached as standard process.
  • Design Models and 4D - It was suggested that design models should be built with construction sequencing in mind. This requires the contractor to be available in the Design Meetings. However, this was also objected too as it was not seen as a Design role.
  • Handover Design to Building Operator
  • Editable Format - “We wouldn’t give them an Autodesk Revit RVT file as it’s a “chocolate tea pot” in the operational - due to close format. It was suggested that the handover files must be open in nature, for example Industry Foundation Class (IFC).
  • Graphical Data - “Accurate graphical representation of the building” - “What it is, where it is” - It was suggested that a graphical model should naturally form part of the handover package to the building operator, not just asset information. It was suggested that it was important to link the information to this model.
  • Cost Data Should Be Outside Of The Model - The model should not include the costing information; this should be linked but separate.
    Main Challenge Areas

  • Federated Model Role - There was no consensus on who is responsible for the development of federated models, and what they should look like. Some suggested it was the role of the contractor, some the Design Lead. It was noted by some that PAS1192-2:2013 specifically states it is the Design Lead.
  • Data Drops - While the idea of data drops, such as those defined in Soft Landings worked in principle, there seems to be little consensus on how this would shape up on an average project.
  • Quantification Trust - Due to design tolerances, some building elements not being physically modelled including some sub-trade elements and so it is difficult to include these in quantification schedules directly from models. Also measurement rules are different than absolute and so the QS needs to be made aware of what is not there. This mean while we can take out quantities with much more assurance than before, it will not be 100% accurate. However it was suggested that the QS or cost consultant should receive the model.
  • Site Management Model - Design models are not a lot of use on site and while it may be used as a basis will likely need to be remodelled. It was also suggested that if the contractor was brought into the Design Meeting at the start then models may be friendlier to site requirements. “We would draw an 80 storey column, you can’t get that on the back of the lorry!”

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