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BIM and Interoperability for Precast Concrete Funded under a grant from the Charles Pankow Foundation

The Charles Pankow Foundation Advisory Committee November 28, 2007

Earle Kennett National Institute of Building Sciences


Charles Pankow Foundation Grant Project Team – – – – – – – – – – – – –

Earle Kennett, National Institute of Building Sciences Ric Jackson, FIATECH Charles Eastman and Yeon-Suk Jeong, Georgia Tech Rafael Sacks and Israel Kaner, TECHNION Davis Chauviere and Kelly Garcia, HKS Architects High Concrete Arkansas Precast Tekla Inc. Structureworks Inc. Autodesk Inc. Design Integrations (ArchiCAD) Bentley Inc. Gehry Technology


Integrated Work Process

Courtesy CH2M HILL

Design

Planning

BIM

Facility Lifecycle Concept Sustainment

Construction


Knowledge created over time

Functional Processes

Š Edgar 2006

Facility Lifecycle Helix


Facility Information Backbone

Knowledge created over time

Functional Processes

Š Edgar 2006

Facility Lifecycle Helix


Facility Information Backbone

Knowledge created over time

Functional Processes

Š Edgar 2006

Vendors

Facility Lifecycle Helix

Project Teams


Facility Information Backbone Functional Processes Knowledge created over time

BIM Interchanges

Š Edgar 2006

Vendors

Facility Lifecycle Helix

Project Teams



Business Process Value Chain



Contracted Exchange

Within NBIMS Scope

Not in Scope



Project Overall Goal The project sought to explore and define the functional requirements for a BIM standard for precast concrete. • Study two parallel design and detailing processes (2D CAD and 3D BIM) between precast concrete design and fabrication (3D Modeling Experiment) • Test building model data exchanges between BIM software and precast concrete fabrication software (Benchmark Date Exchange Tests) • Document efficiency comparison between 2D CAD and 3D BIM processes for precast concrete design and fabrication • Compile an Information Delivery Manual (IDM) for a precast concrete BIM standard


IFC File Tekla Model


Project Comparative Analysis


Current Practice 2D Architectural Faรงade - contract drawings Sketch layout of faรงades without drawing individual panels; connections not fixed

New Practice 3D Architectural Faรงade - contract model Assembly model with all piece marks identified; parts defined to reflect fabrication practices

2D Precast fabrication; Faรงades - & piece marks Re-drawn as assembly drawings; each piece then drawn from assembly, defining connections, embeds, passthrus, reinforcing

3D Precast Faรงade generate piece marks Refine assembly model; pieces modeled in relation to assembly model, with connections, embeds, pass-thrus, reinforcing

Shop Drawing coordination Production Floor Management Coordinate multiple drawing sets; management production on paper-based tracking

Shop Model coordination Production Floor Management All pieces in 3D make conflict checking simple, largely automated; materials, production tracked from assembly/erection model


2D BIM Workflow


3D BIM Workflow


19

Labor hours comparison Profession

Precaster

Activity

2D CAD

3D BIM

Productivity gain

Drafting

830

350

58%

Design

440

Total hours reported by Arkansas Precast: 830 + 440 = 1,270 hours According to PCI Journal benchmark (Sacks et al. 2005) medium-sized architectural projects consume 37.5 hr/1000sq.ft. This façade is 35,000 sq.ft. → 1,312 hours.

Sacks, R., Eastman, C. M., Lee, G., and Orndorff, D. (2005). "A Target Benchmark of the Impact of Threedimensional Parametric Modeling in Precast Construction." Journal of the Precast/Prestressed Concrete Institute, 50(4), 126-139.


Benchmark Data Exchange Tests

Architectural BIM Precast BIM

Structureworks

Tekla Structures

Revit

Bentley Arch.

ArchiCAD

Digital Project


Group A

Group B

ArchiCAD (V.10.0) IFC (SMC, TNO) Tekla Structures (R.13.0)

Bentley Architecture (V.8) DWG (AutoCAD) Digital Project (V1,R3)

Structureworks SAT or STP (Hoops)

Revit Building (V.9.1)

IFC DWG SAT or STP

Not supported Supported but not checked


Test Model


Part Structure


Part Structure


Representation of Building Elements in BIM Tools


ArchiCAD – IFC file - Geometric shape corrupted - More detailed explanation is needed

AC

IFC TS

BA DWG DP

SW SAT

RB


Bentley Architecture – IFC file - Façade panels are corrupted - More detailed explanation is needed

AC

IFC TS

BA DWG DP

SW SAT

RB


Digital Project – IFC file - No thickness of slab element

AC

IFC TS

BA DWG DP

SW SAT

RB


Revit Building – IFC file - No geometric shape errors

- Import the exported IFC file back • Geometry good • Some objects are changed into generic models (proxy elements)

AC

IFC TS

BA DWG DP

SW SAT

RB


Comparing Data Objects Used – Geometry Used ArchiCAD • IfcBuildingElement • IfcFacetedBrep – IfcClosedShell – IfcFace Bentley Architecture • IfcCurtainWall • IfcFacetedBrep – IfcClosedShell – IfcFace Digital Project • IfcBuildingElementProxy • IfcShellBasedSurfaceModel – IfcOpenShell – IfcFace Revit Building • IfcWall • IfcFacetedBrep – IfcClosedShell – IfcFace


Group A

Group B

ArchiCAD (V.10.0) IFC (SMC, TNO) Tekla Structures (R.13.0)

Bentley Architecture (V.8) DWG (AutoCAD) Digital Project (V1,R3)

Structureworks SAT or STP (Hoops)

Revit Building (V.9.1)

IFC DWG


ArchiCAD – IFC file - Tekla - Objects are modeled in boundary representation and not using higher-level geometry representation such as swept objects.

- The file does not contain any profile of objects. No conversion is possible where standard items do not appear in any IFC entity or attribute.

AC

IFC TS

BA DWG DP

SW SAT

RB


Bentley Arch. – IFC file - Tekla - Test file from Bentley Architecture export swept solids for walls, beams, columns and other objects. - However, no standard ‘profile’ name is retrievable. - Others are represented in B-Rep solids.

AC

IFC TS

BA DWG DP

SW SAT

RB


Digital Project – IFC file - Tekla - The file is invalid not as being IFC 2x3 certified but violates several side agreements that are addressed in IFC Building Smart ISG agreements, especially by exporting the Bezier curve. - Front panel objects, which are Windows, doors, staircases, are missing from the import because the objects are represented by surface model.

AC

IFC TS

BA DWG DP

SW SAT

RB


Revit Building – IFC file - Tekla - IFC file from Revit shows fewer problems. This does not mean Revit has best IFC interface, but more likely a best match with Tekla’s importing capability.

AC

IFC TS

BA DWG DP

SW SAT

RB


Details Revit Building ifc Model scale

O

Bentley Architecture

dwg

O

ifc

Diff

Digital Project

dwg

O

Default location and offsetting

Y (global) direction offset

ifc

ArchiCAD

dwg

ifc

dwg

X

X

O

X

X

X (global) direction offset

O

Left corner (perpendicular) Right corner (rounding) Top panels Middle relief

Top

geometry

O

O

O

O

X (missing)

X

O

O

Middle

geometry

O

O

O

O

X (missing)

X

O

O

Bottom

geometry

O

O

O

O

X (missing)

X

O

O

decoratio n

geometry

O

O

O

O

X (missing)

X

O

O

Upper gap

geometry

O

O

O

O

X (missing)

X

X

O

Top

geometry

O

O

O

O

X (missing)

X

O

O

Middle

geometry

O

O

O

O

X (missing)

X

O

O

Bottom

geometry

O

O

O

O

X (missing)

X

O

O

number

geometry

O

O

O

O

X (missing)

X

O

O

geometry

geometry

O

O

O

O

X (missing)

X

X: Not concaved

O

O

Not curved, upper right missing

O

X (missing)

X

X: No curve relief

O

Decorated window

geometry

O






Information Delivery Manual (IDM) data exchange requirements and workflow scenarios




Workgroup Formation & Definition of Requirements – Scope, stakeholders, industry need/potential adoption – Use case, process description – Universal & regional/local requirements

Workgroup Formation Process Map Exchange Requirements and Business Rules Standard Requirements

• Exchange Requirement Models

Exchange Design – Common concepts – Non-schema-specific data components

Generic Model View Definition Standard Design

Model View Definition and Implementation Specifications

Facilitate SW Product Implementation and Certification

Data Model View & Implementation Specification – For implementation in software – Facilitation and Certification of software implementation

Implementation in Software

Generic BIM Guide Product-Specific BIM Guides BIM Creation BIM Exchange and Data Validation BIM Data Reuse and Extension Use in Industry

NBIM Standard Development and Use

Software Used To Create BIMs in Projects – Guides describe exchanges regardless of software. – Guides by software vendors describe how their application supports the exchange requirements. – Project contracts can specify Standard exchanges. – BIM exchange files can be tested for correct content. – BIM data can be reused and repurposed.


PROGRAM


DESIGN


Barriers to Effective IFC Exchange • Non-uniform use of the BIM software • Non-uniform mappings between internal native objects and IFC schema objects • Variations in representations of geometry • Doman-specific objects missing from the IFC 2x3 schema


Domain-specific BIM Exchange Schema • Incorporate all of the basic building element objects that are needed in their native model schemas • Ensure that their IFC import and export translators incorporate all of the necessary objects and their relationships between the objects


CONSTRUCT












Generic BIM Guide Product-Specific BIM Guides BIM Creation BIM Exchange and Data Validation BIM Data Reuse and Extension Use in Industry


NEXT STEPS • Industry review of Information Delivery Manual (IDM) and Model View Definition (MVD) • Industry consensus • Software vendor implementation of final Model View Definition • Benchmark testing of software data exchange (test bed)