Digitale bygningsmodeller
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Værdien af at stille krav:
- Erfaring viser, at digital projektering i bygningsmodeller giver bedre overblik og bedre kvalitet, i form af et bedre koordineret projekt.
- Projekteringssamarbejdet i de digitale bygningsmodeller fungerer bedst i et tæt samarbejde, hvor fagmodellerne løbende bliver samlet og sammenlignet i en fællesmodel, og kommenteringen foregår ved hjælp af BCF formatet. Derfor kan det give værdi også at stille krav om fælles projektkontor.
- Erfaring viser, at både bygherre, brugere og driftsfolk har lettere ved at se og kommentere på løsningsforslag, når de vises i en 3D model. Derfor bør kommentering foregå direkte i IFC fællesmodellen, gennem et godt og brugervenligt værktøj, som opsamler kommentarerne ved hjælp af BCF formatet. Evt på projektweb, hvis det kan håndtere det.
- De foreløbige erfaringer viser at digitalisering af økonomi og tidsplanlægning giver bedre styring af projekter. Populært kaldet 4D og 5D BIM, eller blandt entreprenører: Virtual Design and Construction, VDC. Det dækker over anvendelsen af 3D BIM modeller, som grundlag for priskalkulationer, fakturering og tidsplaner, gerne kombineret med LEAN metoder og lokationsbaseret tidsplanlægning.
- 4D og 5D BIM kan foregå i software som samler modeller, priser og tidsplanlægning, eller der kan sættes workflows op som forbinder BIM software med kalkulations-software og tidsplanlægningssoftware. Værdien af 4D og 5D BIM ligger i høj grad i at få data ind fra byggepladsen hurtigt, i valide data og i fremskrivninger og prognoser.
Opmærksomhedspunkter
- Istedet for at udbyde totalentreprise med en kvalitetsplan, kan man lade de bydende konkurrere på en samlet projekt- og produktionsplan, hvor de også beskriver deres metoder og værktøjer til bl.a. digital projektering (en BIM execution plan), og herunder kvalitetsplan med digital kvalitetssikring som konsistens- og kollisionskontrol, som skal hænge sammen med den mere traditionelle kvalitetssikring af projeket.
- Dette kræver gennemtænkte kvalitative tildelingskriterier og en grundig vurdering af de bydendes metoder og værktøjer.
- I mellemformer af Totalentreprise samt OPP og IPD bør Bygherren selv formulere kravene i en IKT specifikation, afpasset efter projektets størrelse og kompleksitet.
- Digitalisering af eksisterende forhold kan være en del af udbuddet, så det bliver projektteamets eget ansvar at levere et brugbart grundlag for projekteringen.
- Hvis der allerede foreligger digitale modeller af eksisterende forhold, skal de beskrives grundigt i en modeljournal, dvs. hvad de indeholder, hvordan de er opbygget, og i hvilket informationsniveau (LOD og LOI).
Lovgivning:
Aftalegrundlag:
Internationale standarder:
- EN ISO 16739:2016
- BIM Collaboration Format, BCF
Teknisk fælleseje:
Tjekliste
Udbudstekster, eksempler
Note: Nedenstående eksempel på udbudstekst er udtryk for bygherrens valg på tidspunktet for udbud af den konkrete byggesag. Bygherreforeningen anbefaler, at man fremadrettet bruger det nye danske aftalesystem, dvs. AB18, ABR18, ABT18 mv., som grundlag.
Digitale bygningsmodeller, udbudstekster fra case Tønsberg projektet:
Capability maturity assessment: (for design, a similar one was in the tender for contractors, extended to LEAN and 4D planning as well as off-site production)
In this document, the Building Commissioner has presented some requirements and some ambitions as to how to execute the design phase of the project. Bidders are required to describe their overall execution model for design and also answer the specific questions in this appendix with regard to their design approach and experiences related to BIM use. Questions are structured according to the bullet point list below. The background for this is that the project execution model is Integrated Product Delivery and it requires a certain competence and skill level among the team members.
ICE part of VDC
Utilizing the Integrated Concurrent Engineering (ICE) concepts from Virtual Design and Construction (VDC) for productive and effective design process leading to a cost efficient, functional and operational building support the following:
- short-cycle decision making (reduce design time and explore more alternatives);
- quality assurance;
- efficient data exchange;
- Target Value Design;
- Design for Manufacture and Assembly (DFMA).
BIM requirements, afsnit 6:
BIM Execution Plan (BEP)
The participants should structure their work processes, organization and lines of communication to be adapted to the use of BIM and open BIM in an appropriate manner. At the start of design, the design group together with the BC should draw up a post-contract BIM Execution Plan (BEP) for the use of BIM in the relevant project phases in collaboration with the health trust. The Execution Plan should be related to the quality assurance system that will be used. It should be based on this requirements specification. The Execution Plan must not affect responsibilities according to the Building Regulations (PBL).
Statsbygg’s BIM manual 1.2.1 chapters D and E as well as SiV’s BIM manual provides important input to such an execution plan.
The BIM Execution plan should as a minimum determine:
- How access to BIM and other project material is managed and controlled.
- How BIM is used in the daily design work.
- How the BIM model is established and quality assured, including use of interdisciplinary checks and collision detection, and how this is linked to the participants’ quality systems.
- How the BIM model is matured with the number of objects, object geometry and attributes/properties in the course of sub-milestones and milestones.
- How the model is divided in appropriate areas (storeys, department, systems etc.).
- How the model is otherwise used, which simulations and calculations are be carried out based on the model.
- How the use of BIM is related to the traditional quality assurance system.
BIM requirements, afsnit 10.2:
Statsbygg’s BIM Manual
The BIM-REQ and BIM-DOC supersedes the Statsbygg BIM manual.
Statsbygg’s BIM manual has been used in various versions since 2008 in many projects, also outside Statsbygg. It is assumed that this is common knowledge.
The health trust point of departure are the same requirements to model delivery as Statsbygg’s BIM manual version 1.2.1 from 2013-12-17. The Project will make more requirements to BIM than Statsbygg’s BIM manual. But, where there are overlapping requirements, the practice should be the same, unless otherwise agreed.
BIM requirements, afsnit 15:
Model Deliverables
When the concept phase (Concept model), pre-project (coordinated model), detail project /bid (bid model), contract awards (contract model), any finished supplier designs (production model) and at a contractual point in time before final hand-over (operating model) are completed, the following shall be delivered for all project disciplines:
Complete models in IFC format (ISO 16739) appropriately divided into the project specified partitioning’s like buildings, production area, contract etc.
Complete model in the original partitioning and the file format the models / the individual parts of the model are modelled in (native or proprietary file format). It is important that the native file delivered shall be the same file that the Ifc file is generated from. The BIM tool file/library use should therefore be documented. This file shall have the same filename as the ifc file.
Documentation of object types in the shape of lists over all object types in the model with TFM identification (Statsbygg Interdisciplinary Tagging System – Statsbygg PA 0802) or the identification system that was selected and with original (native/proprietary) type name and IFC class. The developer will provide the template for the list that defines which fields to include.
Object library with all corresponding objects. If it is not available as a specific library file, there shall be as a minimum be delivered a cleaned model file with one object of each type. This should be delivered in both the original (native/proprietary) format and in IFC format.
2D objects libraries or symbol libraries, and any single symbols that the project has added to the symbol libraries of the developer.
The information that is required to generate the drawings that are a part of the delivery, i.e. information about sheets, view, layouts, tags etc. in or out of the model.
Documentation of the file structure for the model both in the original format and IFC format with indication of the version number of modelling tools and IFC export. If the partitioning of the model is different in the native file format and IFC format, the relationship between the original files and IFC files should be apparent. If “work sets” (Revit) are used to filter the model, or equivalent mechanisms in other programs, these should also be documented. Help files in other formats should also be documented.
This shall be described in the Task Information Delivery Plan (TIDP) and integrated into the Master Information Delivery Plan (MIDP) for the project.
- “Complete model” means, in addition to the traditional discipline models from the different design disciplines, also models from other parts of the supply chain as suppliers and contractors and suppliers from manufacturing, for instance modelling for prefabrication of concrete elements etc.
All model deliverables shall be considered as a part of the total delivery and be a prerequisite for total delivery being completed on time, and thus included as a basis for any daily penalty calculations.
Deadline for delivery of BIM follows the production drawing. If the finished production drawings are not one delivery, a milestone plan should be established for when groups of production drawings and corresponding parts of the model should be delivered. Accordingly, if the hand-over is done as partial hand overs, e.g. for test operation of the systems or geographic sections, a milestone plan should be established for these releases.