U S General Services Administration Public Buildings Service Office of the Chief Architect Capital Construction Program Introduction The Warroad Border Station is a proposed 24 000 square foot border station located on the US Canadian border in Minnesota Figure 1 The project team is pursuing LEED silver certification After discussions internally and with the project team it was determined that rather than conducting an energy analysis on one or more particular project design options such as evaluating mechanical system options or other specific architectural impacts on energy usage the Warroad Border Station project would be used as a case study survey on the current capabilities of energy thermal comfort and daylighting building analysis tools leveraging the use of BIMs to inform GSA project teams and to contribute to the development of the BIM Guide Series 05 Energy Performance and Operations Figure 1 Warroad Border Station 1 Figure 2 shows Figure 1 a project Narrative depicting the work flow of this case study Using CAD data provided by the projectBorder team aStation BIM was constructed in Autodesk Revit and Graphisoft ArchiCAD The resulting BIM models Warroad were evaluated in the following building analysis tools Solibri Model Checker model checker Green Building Studio energy FLOVENT CFD thermal comfort eQUEST energy ECOTECT thermal daylighting and shading Integrated Environmental Solutions energy thermal daylighting shading and Riuska energy GSA s National 3D 4D BIM Program Warroad Border Station Pilot Study 1 U S General Services Administration Public Buildings Service Office of the Chief Architect Capital Construction Program Figure 2 Warroad Border Station Narrative A major focus of the study in addition to evaluating the current functionality of the building analysis tools was to evaluate the current state of interoperability between the tools and the project information available through the existing CAD data and the BIMs constructed using that CAD data Data schemas such as green building extensible markup language gbXML Industry Foundation Classes IFC DWG and DXF and ACIS Solid Model SAT were all evaluated as part of this case study Part I Building Information Models Software Description Autodesk Revit Architecture MEP 2008 and Graphisoft s ArchiCAD 10 are several of the leading BIMauthoring tools on the market today Each allows for complete object oriented design and information storage and transfer Data Exchange Methodology GSA s National 3D 4D BIM Program Warroad Border Station Pilot Study 2 U S General Services Administration Public Buildings Service Office of the Chief Architect Capital Construction Program Using existing CAD drawings provided by the project team BIMs of the border station were created in Autodesk Revit and Graphisoft ArchiCAD Both DWGs and DXFs were used to construct the models by importing them into the BIM authoring tools and tracing over the construction drawing lines Only layers including walls internal and external windows doors roofs floors slabs spaces dimensions and structural grids were imported Structural elements were ignored Modeling Results Wall thicknesses were based on both construction drawing lines and construction details Due to the tracing methodology space dimensions between the two models were not exact though the minor variations that existed were negligible for analysis purposes All the elements in both models were manually populated with relevant thermal data to evaluate the ability of the BIM authoring tools to capture this data during export Spaces or zones were defined for all interior areas including mechanical and elevator shafts inter construction voids and plenum spaces Figure 3 shows the resulting models Figure 3 CAD to Revit and ArchiCAD Models Revit Model Architectural Desktop ADT Model ArchiCAD Model Part II Solibri Model Checker SMC Software Description Solibri Model Checker is a software that analyzes Building Information Models for integrity quality and physical safety SMC can import a building model either using the IFC format or via a direct ArchiCAD link visualize the design in 3D check the model against a set of rules create a report of the potential problems and create and show presentations of interesting points of the design 2 Data Exchange Methodology GSA s National 3D 4D BIM Program Warroad Border Station Pilot Study 3 U S General Services Administration Public Buildings Service Office of the Chief Architect Capital Construction Program The Revit and ArchiCAD models were checked for accuracy using an IFC import into SMC Modeling Results Wall adjacencies floor and roof connections and space definitions were all confirmed Figure 4a shows the Revit model displayed as spaces only within the SMC interface and 4b shows the ArchiCAD model with surfaces Figure 4 SMC Models 4a 4b Part III Green Building Studio GBS Software Description Green Building Studio is a web based building energy analysis tool developed by a company of the same name Green Building Studio Inc developed the open Green Building XML schema that is used for intelligent data exchange The Green Building Studio web service offers interoperability between building design teams using Autodesk Graphisoft and other CAD products engineers using software such as DOE 2 EnergyPlus Trane Trace700 IES VE and other tools for load analysis HVAC sizing and green analyses 3 Exports in the gbXML format are uploaded to the GBS web service and a DOE 2 2 simulation is quickly run on the uploaded file with all the relevant thermal data automatically populated based on building size and type A number of outputs are then made available to the user including a newly populated gbXML file a DOE 2 Input File and EnergyPlus Input File and a VRML file These output files are available for download for the user to be used in downstream applications The first five runs of a project are free to the user with additional runs priced based on building size The user also has the ability to consider a number of design alternatives within GBS Data Exchange Methodology Both Revit and ArchiCAD allow for gbXML exports with ArchiCAD having a direct link to GBS via an ArchiCAD add on This direct link comes in the form of a user interface within ArchiCAD to define the spaces necessary to export to GBS Both types of ArchiCAD gbXML exports via the add on and using the save as function were evaluated in GBS There are a number of important modeling requirements to follow to ensure the
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