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Structural Timber and Concrete Level of Detailing

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Structural Timber and Concrete Level Of Development (LOD): When to Draw the Line and Where to Model It! IKERD Consulting: Will F. Ikerd, PE, CWI, LEED AP, Principal, President ITW Building Components Group: Steve Bumbalough, Product Manager, Global Software Development IKERD Consulting: Brenda Herrera Ikerd, CFO, (English & Spanish Version, AU Online) Code SE4912 (Las Vegas, Live) Companion Virtual Personations: SE5475 (Virtual English) | SE5118 (Virtual Spanish) Printed 2011-11-13 Description: This class will provide an in-depth discussion of the level of development (LOD) of structural timber and concrete models at the different stages in a building lifecycle: design, construction and ownership. We will consider the new AIA BIM Protocol Exhibit E202 that defines models on a scale of 100 to 500. The class will cover how structural timber and concrete models are used by architects, mechanical engineers, construction managers, sub-contractors, and fabricators. Most importantly, the class will discuss how each of these stakeholders uses timber and concrete structural models differently and need different content. We will demonstrate how the newly issued Structural Engineering Institute LOD BIM (authored by speaker Will Ikerd) can be used to define team expectation of what should be modeled. Practical examples of model development issues will be shown, along with effective approaches to resolve the challenges of using the SEI LOD model as an early BIM planning tool. Learning Objectives At the end of this class, you will be able to: Describe what LOD is. Identify who LOD should be used on your project. Describe good practices for BIM models when working with teams on collaborative projects. Speakers: Will Ikerd, PE, LEED AP [email protected] Principal, President IKERD consulting Steve Bumbalough [email protected] ITW Building Components Group Product Manager, Global Software Development Brenda Herrera Ikerd [email protected] Principal, CFO IKERD consulting
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  • Structural Timber and Concrete Level Of Development (LOD): When to Draw the Line and Where to Model It! IKERD Consulting: Will F. Ikerd, PE, CWI, LEED AP, Principal, President ITW Building Components Group: Steve Bumbalough, Product Manager, Global Software Development IKERD Consulting: Brenda Herrera Ikerd, CFO, (English & Spanish Version, AU Online)

    Code SE4912 (Las Vegas, Live) Companion Virtual Personations: SE5475 (Virtual English) | SE5118 (Virtual Spanish) Printed 2011-11-13

    Description: This class will provide an in-depth discussion of the level of development (LOD) of structural timber and concrete models at the different stages in a building lifecycle: design, construction and ownership. We will consider the new AIA BIM Protocol Exhibit E202 that defines models on a scale of 100 to 500. The class will cover how structural timber and concrete models are used by architects, mechanical engineers, construction managers, sub-contractors, and fabricators. Most importantly, the class will discuss how each of these stakeholders uses timber and concrete structural models differently and need different content. We will demonstrate how the newly issued Structural Engineering Institute LOD BIM (authored by speaker Will Ikerd) can be used to define team expectation of what should be modeled. Practical examples of model development issues will be shown, along with effective approaches to resolve the challenges of using the SEI LOD model as an early BIM planning tool.

    Learning Objectives At the end of this class, you will be able to:

    Describe what LOD is. Identify who LOD should be used on your project. Describe good practices for BIM models when working with teams on collaborative projects.

    Speakers: Will Ikerd, PE, LEED AP [email protected] Principal, President IKERD consulting

    Steve Bumbalough [email protected] ITW Building Components Group Product Manager, Global Software Development

    Brenda Herrera Ikerd [email protected] Principal, CFO IKERD consulting

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    About the Speakers: Will Ikerd, P.E., CWI, LEED AP e: [email protected] Will Ikerd is a nationally recognized consultant in structural engineering and building enclosures utilizing Building Information Modeling in both design and construction. Will also specializes in implementing BIM strategies for construction management firms interested in expanding their work in Virtual Design and Construction (VDC). He co-chairs the national American Society of Civil Engineers (ASCE) Structural Engineering Institute - Council of American Structural Engineering (SEI-CASE) committee on BIM, is co-chair of the BIM Forum's Designer's Sub-forum, and chairs the Structural Engineers Association of Texas Committee on BIM. Will is also a member of American Institute of Steel Construction (AISC) Technology Integration (TI) committee for the steel industry use of BIM and a member of American Concrete Institute (ACI) 131 Committee on BIM for concrete. He is a practicing professional engineer who frequently speaks and writes about BIM, civil, and structural engineering, and building enclosure design. He is Principal at IKERD Consulting LLC and can be reached at [email protected].

    Steve Bumbalough e: [email protected] Steve Bumbalough is Product Manager for Global Software Development within the ITW Building Components Group. ITW is a global diversified manufacturer of products that cross over several major market segments such as Industrial packaging, Food Equipment, Polymers, Transportation, and Construction Products. Founded nearly 100 years ago in 1912, ITW started off as a small company manufacturing hand tools and components for the transportation and communications industries prior to WW1.

    Today, ITW has a market cap of roughly $24B with over 5000 product lines and 60,000 employees. We are structured of over 825 different business units in 52 different countries. ITW likes to foster growth thru product innovations, extending current products to new industries and acquiring businesses that improve offerings to their current customer base.

    One of ITWs guiding principles is the 80/20 principle which, in a nutshell, simply acknowledges that 80% of a companys sales are driven by 20 % of its products sold to key customers. In the truss and wall panel industry the 80 is represented by the light frame wood industry. Between builders and the supply chain, residential and light commercial markets remain one of the most highly fragmented in the construction industry as a whole. So providing solutions to connect these dots and define levels of development for the digital models based on corresponding deliverables is what ITW does. Drawing a home and framing it, optimizing it, and manufacturing it from a single model is revolutionizing BIM for the timber marketplace.

    Brenda Herrera Ikerd e: [email protected] Brenda Herrera Ikerd is a founding partner and majority owner of Ikerd Consulting LLC and its subsidiary i2concepts.com, a building information modeling and technology integration consultancy that focuses on the use of Virtual Design and Construction (VDC). She has worked in design and construction in the United States and Mexico since the mid-1990s before starting her BIM and VDC consulting firm in 2003 that specializes in the areas of structure and building envelope. She is currently co-authoring a book on VDC with Autodesk Navisworks software in both English and Spanish. She can be contacted at [email protected].

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    Contents Description: ......................................................................................................................................... 1Learning Objectives ............................................................................................................................ 1Speakers: ............................................................................................................................................ 1About This Session & Paper ............................................................................................................... 4Definitions ........................................................................................................................................... 4Ikerd's Rules Of Thumb for Design Level Structural Modeling (100-350 LOD) .................................. 71. Avoid Re-modeling, Strive for Collaboration (IFC & CIS/2): ................................................. 72. Clearly Define the Local X,Y,Z Origin ................................................................................... 73. Model Typical 1/8" Plan Content for Design (LOD ~300) ..................................................... 84. Model Structure as it will be Constructed: ............................................................................ 85. Do Not Duplicate Model Content Across Disciplines (A, S, & MEP) ..................................... 86. Use Shared Model When Two Disciplines Need to Control the Content: ............................. 87. Don't Assume Construction Ways & Means During Design ................................................. 88. Match BIM Material with Project Specifications (LOD 300) .................................................. 99. Have Senior Engineers in Responsible Charge Open & Review their Models ..................... 910. Not All Steel, Concrete, Masonry and Wood Content is Structural .................................... 1011. Train the team Inside & Out ................................................................................................ 10About the E202 OBJECT CLASSIFICATION UniFormat & MasterFormat ....................................... 11Hierarchical Structural LOD Model, version 2010.11 ........................................................................ 13Model Management .......................................................................................................................... 15Initial Responsibilities of the Structural Model .................................................................................. 15File Formats ...................................................................................................................................... 15LOD 100 ............................................................................................................................................ 17LOD 200 ............................................................................................................................................ 18LOD 300 ............................................................................................................................................ 19LOD 350 ............................................................................................................................................ 20LOD 400 ............................................................................................................................................ 21LOD 450 ............................................................................................................................................ 22LOD 500 ............................................................................................................................................ 23Example, Tilt-Up Panel Concrete (CSI MF# 03 47 13) & Shared Models ........................................ 24Resources & Bibliography ................................................................................................................. 29

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    About This Session & Paper This paper suggests protocols, expected levels of development, and authorized uses of Building Information Models in the structural aspects of a project. It also recommends specific responsibility for the development of structural model content to a defined Level of Development at key project milestones that are to be developed by the project teams. This paper is only meant as a guide to aid project teams in discussing the structural level of development on their projects and should not be used without a thorough consideration of the contents application and consequences. This paper references the AIA E202 (American Institute of Architects [AIA], 2008) which is a document that provides a framework for defining model definition. In addition to the E202, the session will present information from the authors work as well as content that they have adapted from the Consensus Doc 301 BIM Addendum (ConsensusDOCS, 2008) , the AISC Steel Detailing manual (American Institute of Steel Construction [AISC], 2009) and ACI's concrete reinforcing detailing manual (American Concrete Institute [ACI], 2008). Finally, examples are shown on the structural LOD that could be applied to most typical projects. The paper also includes sample general notes related to BIM in structural construction documents, and an excel spread sheet tool to aid in defining a projects structural LOD. Project contract forms such as design-bid-build, design-build, design-assist and IPD will be mentioned but are beyond the focus of this session. It is assumed that regardless of the project form, all members of the design team can work together and collaborate with the construction managers team.

    Definitions The following are common definitions used in this paper that have been adapted from the AIA E202 and the 301 BIM Addenda.

    Building Information Model (BIM) is defined as a relational database of building objects that stores information such as geometry, material, schedule, cost and many other aspects of the objects. A Building Information Model(s) is a digital representation of the physical and functional characteristics of the Project it is created for. Building Information Modeling means the process and technology used to create the models.

    Federated Model is defined as a relational database of building objects that store information such as geometry, material, schedule, and cost that is created from two or more separate models. An example of a federated model would be the combination of an architectural BIM, a structural BIM and a MEP BIM. The 301 BIM Addendum defines a Federated Model as "a Model consisting of linked but distinct component Models, drawings derived from the Models, texts, and other data sources that do not lose their identity or integrity by being so linked, so that a change to one component Model in a Federated Model does not create a change in another component Model in that Federated Model."

    Level of Development (LOD) in the AIA E202 describes the level of completeness to which a Model Element is developed (Architects, American Institute of, 2008). LOD should only be used to describe individual model objects. It is an incorrect application of LOD to refer to an overall model as a particular LOD, rather a model is a collection of objects that are varying LODs.

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    Level of Detail (LOD) is a deprecated term that should no longer be used in describing BIM content. The level of detail of model object geometry is often very misleading as a measure of the quality of the information that objects represents. As an example, a steel open web joist in Revit Structure looks highly detailed at the fine level of display. However, the web geometry is only suggestive and not developed. The geometry detail is very precise but the information the object conveys is in-accurate and not developed. For this reason, the AIA and the AGC BIM Forum use the term Level Of Development to describe a model object.

    Model Element is defined by the AIA E202 as a portion of the Building Information Model representing a component, system or assembly within a building or building site. For the purposes of this paper focused on structural content, Model Elements are represented by the Construction Specifications Institute (CSI) MasterFormat classification system with cross referencing to the Omniclass system.

    Model Element Author is defined by the AIA E202 as the party responsible for developing the content of a specific Model Element to the LOD required for a particular phase of the Project. Model Element Authors should be identified at the beginning of a project in the LOD table that accompanies this document.

    Model User is defined by the AIA E202 as any individual or entity authorized to use the Model on the Project, such as for analysis, estimating or scheduling.

    Construction BIM is defined by the 301 BIM Addendum as "a Model that (a) consists of those aspects of the Project that are to be modeled as specified in the BIM Execution Plan prepared pursuant to this Addendum; (b) utilizes data imported from a Design Model or, if none, from a designer's Construction Documents; and (c) contains the equivalent of shop drawings and other information useful for construction." As a reference, the authors consider this a BIM with a LOD greater than 300 as described in this paper.

    Contribution is defined by the 301 BIM Addendum as " the expression, design, data or information that a Project Participant (a) creates or prepares, and (b) incorporates, distributes, transmits, communicates or otherwise shares with other Project Participant(s) for use in or in connection with a Model for the Project." This is typically adding or modifying a BIM to change its LOD.

    Contributor is defined by the 301 BIM Addenda as "a Project Participant who makes a Contribution." In the structural domain these would include Owners, Architects, Construction Managers, Steel Fabricators, and Erectors.

    Design Model is defined by the 301 BIM Addendum as "a Model of those aspects of the Project that (a) are to be modeled as specified in the BIM Execution Plan prepared pursuant to this Addendum and (b) have reached the stage of completion that would customarily be expressed by an Architect/Engineer in two-dimensional Construction Documents. This shall not include Models such as analytical evaluations, preliminary designs, studies, or renderings. A Model prepared by an Architect/Engineer that has not reached the stage of completion specified in this definition is referred to as a Model." This is typically a BIM with a LOD less than or equal to 300.

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    Drawings are defined by the 301 BIM Addendum as "(a) those two-dimensional plans, sketches or other drawings that are Contract Documents under the Governing Contract and are created separately from, and are not derived from, a Model and (b) those two-dimensional projections derived from a Model supplemented with independent graphics and annotations specified by the Parties to be Contract Documents."

    Full Design Model is defined by the 301 BIM Addenda as a Model consisting of coordinated structural, architectural, MEP and other Design Models designated in the BIM Execution Plan to be produced by the design team." This is typically comprised of BIMs with LODs of 300 but may require greater LOD than 300.

    Level of Development 350, Pre-construction Coordination Model Elements is defined by the author as that content that goes beyond what designers have information to show but is less than a manufacturing level of development. This could include construction engineered items such as light gage kicker locations, open web joist web member configuration, miscellaneous steel braces, and curtain wall systems. This content is not always available from designers due to the information being contingent on which manufactures are selected by the contractor. However, content such as these can effect 3D spatial trade coordination and is typically needed before full fabrication level of development model elements (LOD 400) can be made. Models with LOD of 350 can be a hybrid of manufacturing level information that is known along with 3D massing based on rational assumptions for that content that falls short of a LOD 400.

    Level Of Development 450, Site Construction \ Erection Content Model is defined by the author as that content that goes beyond what is needed in the LOD 400 fabrication model to include temporary building content that is used during onsite construction. This could include construction items such as erecting braces, form work bracing, shores, back shores, scaffolding, and cranes. This content can be beneficial when conducting site planning and 4D scheduling of the construction.

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    Ikerd's Rules Of Thumb for Design Level Structural Modeling (100-350 LOD) The following are my opinions on eleven topics I believe are fundamental to workable model element development in the design and construction of structures. Some of them relate more to sociology than technology (9, 10, and 11). As you review them, please send your comments and feedback to me ([email protected]). Below is a summary of my eleven rules of thumb followed by a more detailed definition of each:

    1. Avoid Re-modeling, Strive for Collaboration (IFC & CIS/2) 2. Clearly Define the Local X,Y,Z Origin During Design 3. Model Typical 1/8" Plan Content for Design 4. Model Structure as it will be Constructed 5. Do Not Duplicate Model Content Between A, S & MEP 6. Use Shared Model When Two Disciplines Need to Control A Given Content 7. Don't Assume Construction Ways & Means During Design (Ask!) 8. Match BIM Material with Project Specifications 9. Have Engineers in Responsible Charge Open & Review Their Models 10. Not All Steel, Concrete and Wood Content is Structural 11. Train the Team Inside & Out on Structural BIM LOD

    1. Avoid Re-modeling, Strive for Collaboration (IFC & CIS/2):

    Where possible, avoid modeling content that will have little downstream value. Most 3D structural detailing applications used do not readily import Revit content beyond the basic standard member information. As an example, approximately 90% of the North American steel detailers working in 3D are using one of two non-Autodesk applications for steel detailing. To date, these common steel detailing applications do not readily read in any custom families such as connections, gusset plates, and built-up members. Strive for modeling content that will export to IFC and CIS/2 formats when possible. Critically review the value of modeling content if it cannot be used downstream in construction via model hand-off or export.

    2. Clearly Define the Local X,Y,Z Origin The project general notes and specification should clearly define the local relative X, Y, Z coordinates that other trades will use in construction that are coordinated with the structural model. I typically prefer defining the X,Y coordinates of the origin (0,0) at the southwest most column grid intersection with a south and west offset of 10, 100 or 1000 feet depending on the project size. The southwest column intersection is chosen so that the structure is in a positive X-Y coordinate system. The offsets of 10, 100 or 1000 feet south and west of the origin are so that any portions of the building that extend south or west of the project origin grid intersections will also be within a positive X-Y coordinate system. The Z elevation should be defined as 0, 100' or absolute elevation depending on firm preference. I typically use a relative 100 elevation. We also establish plan north as being in the positive Y direction.

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    These rules above form the basis of the projects local relative building coordinate system. This process aids linking the structural model to 3rd party applications that are based on traditional CAD coordinate systems. A benefit of defining the local relative origin early and stating it in the projects general notes is so other models that are developed for shop drawings from the construction documents have a point of reference to follow when they are submitted for review. This local relative building coordinate system is also tied back to the civil engineers state plane coordinate system. The civil state plane absolute coordinate system will then have a set relationship with the structural local relative coordinate system of an X, Y, and Z offset and a Z-axis rotation. Using this set relationship between the civil absolute and structural relative coordinate system, all federated project models can be easily converted to absolute or relative systems depending on the owners preference in their facility management models (LOD 500).

    3. Model Typical 1/8" Plan Content for Design (LOD ~300) For design documents (LOD ~300) model those elements that would traditionally appear on a 1/8" scale structural plan.

    4. Model Structure as it will be Constructed: Model as it is built at LOD 300 and higher. Material strengths and other similar items should be modeled as they are specified in the construction documents.

    5. Do Not Duplicate Model Content Across Disciplines (A, S, & MEP) Do not duplicate model content in different design team models. Rather create a shared model with that shared content that is linked into the structural and architectural model for example.

    6. Use Shared Model When Two Disciplines Need to Control the Content: Use a shared model when two or more designers need to control model elements. Structural content that is a candidate for a shared model would be structural slabs with architectural recesses, load bearing tilt-panels with architectural reveals, miscellaneous support steel and lentil shelf angles, and interior masonry walls.

    7. Don't Assume Construction Ways & Means During Design Structural design (LOD

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    a. Concrete pour breaks and construction joints in continuous concrete sections.

    b. Tilt-wall panel numbers for erecting sequences.

    8. Match BIM Material with Project Specifications (LOD 300) The material names, strengths and other properties used in the structural BIM shall be correlated with the project specifications and general notes. Structural model materials should match those that will be used in the design. My preference is for firms to develop a consistent color template for their structural materials that will aid in checking model content. Projects with existing structures for example that have A36 steel wide flange members with new construction with A992 steel should be modeled with the proper materials for each. Concrete should similarly have a separate BIM concrete material property for each distinct concrete mix design shown in the projects general notes and specifications. This may mean there will be a 3000 psi mix with air-entrainment for exposed concrete members and a second 3000 psi mix without air-entrainment for interior conditions. Steels should have separate material and color at a minimum for the following types :

    a. A500 (HSS sections) b. A36 (angle and plate material) c. A992 (wide flange members) d. F1557 (anchor rod material) e. A53 (pipe material)

    9. Have Senior Engineers in Responsible Charge Open & Review their Models Many states that I am aware of have some requirements to the effect of having the structural engineer who will be sealing the design of a building to have continuous and direct supervision and oversight of the work product used to create the design. This is often part of a states definition of Responsible Charge. As such, it seems reasonable that the structural engineer of record should be opening the models and reviewing the work done in them by their EIT's, junior engineers and technicians. Engineers who have not learned the BIM tools in their office enough to open the models and walk through them cannot make informed decisions about BIM LOD. It is hard to understand how senior engineers who cannot open and review models can manage BIM projects to a LOD and write proposals that define that LOD using a process that they cannot access. I am not suggesting that firm owners and senior engineers model their own projects. However, they should consider having a very basic day to day level of knowledge that will allow them to open the models, walk through them and review the content without having to ask a junior engineer to come help them spin the model around. The level of competency to be able to navigate a model typically only takes one or two hours of effort to learn and allows the engineer in responsible charge to be an active part of their design in BIM. More importantly, it gives them a powerful way to mentor and train the next generation of engineers by

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    having them review their junior engineers work in a graphically rich 3D environment.

    10. Not All Steel, Concrete, Masonry and Wood Content is Structural Not all model content that is steel, concrete, masonry and wood is structural nor should it be in the structural engineers model beyond typical 2D details. Examples of such content would be steel lintels supporting brick over architectural openings, non-load bearing masonry and wood framing architectural partition walls, concrete site paving, concrete recesses in floors and concrete mechanical equipment pads. All such content should be modeled by the discipline that has the greatest control over the design and /or coordination of the element.

    11. Train the team Inside & Out All of the discussion of structural BIM LOD is academic unless everyone who works on the project understands what the goal for the project LOD are. This means that PM and engineers in the firm need to learn how to master the BIM tools. These engineers must then work with their architects and mechanical engineers to form a rational approach to the LOD across the project.

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  • Structural Timber and Concrete Level Of Development (LOD): When to Draw the Line and Where to Model It!

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    is demonstrated in a structural engineers ability to provide project specification in MasterFormat before the structural design is complete. Early in the project, they know what the foundation system will be. For example, the engineer knows if the structure will have concrete (Division 03), masonry (Division 04), steel (Division 05) or timber (Division 06). Furthermore, they know if there design will have open web joists (CSI MF 05 21 19.00), tilt wall (CSI MF 03 47 13.00) and steel roof decking (CSI MF 05 31 23.00) for example. In addition to the six base numbers in MasterFormat, the user can add a two digit decimal suffix to the numbers to further refine the organization of structural content. Thus, I will use MasterFormat in this presentation to aid in defining structural content that compliments the UniFormat used in the AIA E202.

    The first 2 numbers in MasterFormat define the traditional divisions and I suggest using these as the fundamental frame work to organize a discussion around the level of structural model element development. 03-XX-YY.zz: Concrete 04-XX-YY.zz: Masonry 05-XX-YY.zz: Metals (Steel, Ext.) 06-XX-YY.zz: Wood, Plastic, Ext. 10-XX-YY.zz: Finishes 31-XX-YY.zz: Fnd., Earthwork 32-XX-YY.zz: Exterior, Site 36-XX-YY.zz: Misc.

    Sample of authors structural LOD table for structural concrete content.

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    Hierarchical Structural LOD Model, version 2010.11 The following Hierarchical Structural LOD model, developed by the author, is a tool that is being developed to aid in graphically defining structural model content for project teams. The descriptions are only our opinions and the definitions will need to be adjusted depending on the project that they are applied to. My intent in creating this content and the sample models provided is to identify the specific content requirements and associated authorized uses for each Model Element at seven different levels of completeness that are typically at progressively higher-levels of model element development. The general concept is that each subsequent LOD typically builds on the previous level and includes all the characteristics of previous levels. However, in structures and building enclosures this is not always the case. Current practice for many engineered items such as structural steel connections, unitized curtain wall systems, or steel open webbed joists is for the model content to be remodeled in the construction model. The design models (LOD 300 or less) of these elements are rarely being used to electronically automate the creation of the construction models (350+) due to lack of software interoperability.

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    The summary below outlines a sample of a possible seven level system for the structural level of model element development. These levels are namely:

    Ikerd's Structural LOD Adapted From AIA E202-08 LOD LOD CONCEPT

    PHASE TRADITIONAL PHASE (TYP.)

    EXAMPLE

    100 Conceptualization Schematic Design Little model content with some massing, 2D lines and a structural narrative.

    200 Criteria design Design Development General structural objects are modeled to reserve space.

    300 Detailed Design Construction Documentation

    Create 2D construction documents, general estimating and 3D spatial validation

    350 Beyond Detail Design

    Pre-Construction Detailed estimating and 3D Spatial Validation content that is not in the designers models.

    400 Fabrication Detail Construction Administration

    Shop Drawing level information.

    450 Erection & Site Installation

    Construction Administration

    Daily field erection reports added to the structural model. Temporary site items such are cranes, etc.

    500 Facility Management

    Hand Over Maintenance & Renovation

    Sample of authors structural model element LOD for the foundation edge condition of a slab-on-grade system.

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    Model Management The level of model element development is not complete if it does not define who is responsible for managing model content for each defined phase of the project. This paper suggests that the structural model information at LOD of 100 is typically addressed with the aid of structural design narratives as this is all that is typically required early on in a project. When a structural LOD of 200 is required, the structural consultant should be responsible for the content until it is handed off to the preconstruction phase which in the US is typically at a LOD of 300 to 350 on most commercial building projects.

    Initial Responsibilities of the Structural Model The party responsible for managing the structural model shall facilitate the establishment of protocols for the following:

    1. Model origin, coordinate system, and units 2. File storage location(s) 3. Processes for transferring and accessing files with other team members 4. Uploading models to the Spatial Validation manager. 5. Access rights

    File Formats

    The level of model element development is not complete if it does not include a definition of the applications that are used. As an example, the teams BIM Execution plan should state "Models shall be delivered in the following format(s) as appropriate to their use for example: The following examples would be for the level of model element development for design intent which is typically shown as 300 to 350 as suggested in this paper.

    Use of Model Application Required File Format(s) Architectural Design Intent

    Revit Architecture 2011 Source *.RVT Exported *.NWC (Navisworks) Exported *.DWG (for non-Revit team members) Exported *.IFC (for non-Revit team members)

    Mechanical Design Intent

    Revit MEP 2011 Source *.RVT Exported *.NWC (Navisworks) Exported *.DWG (for non-Revit team members) Exported *.IFC (for non-Revit team members)

    Structural Design Intent

    Revit Structure 2011 Source *.RVT Exported *.NWC (Navisworks) Exported *.DWG (for non-Revit team members) Exported *.IFC (for non-Revit team members)

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    The following examples are LOD summary sheets that teams should develop at the beginning of a project. They are:

    LOD 100 LOD 200 LOD 300 LOD 350 LOD 400* LOD 450* LOD 500*

    *For the structural design aspects of the LOD topic of this session, we will mainly focus on LOD 100 through 350. Few owners are currently requiring content that would be defined at LOD 500. Future updates to the structural LOD model will include level 500 topics.

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    LOD 100

    Typical Model Element Content:

    The majority of structural content is actually not modeled at this level. Structural definition is typically accomplished by providing a structural narrative to accompany the architects massing model. This provides ample information for contractors to conceptually price early designs. When structural modeling is created it is only overall structural massing indicative of area, height, volume, location, and orientation in 3D.

    Authorized Uses

    General coordination of space. Reserving required spaces for the building exterior system. Early conceptual estimating.

    Estimating. Conceptual estimating if a structural narrative is provided along with the architectural LOD 100 model. These may be used to develop some estimate based on general area, volume or similar conceptual estimating techniques (e.g., square feet of floor area, pound of steel per square foot, etc.).

    Schedule. The Model may be used for very general project phasing such as 'existing structure' vs. 'new structure'.

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    LOD 200

    Typical Model Content. Overall structural massing indicative of area, height, volume, location, and orientation may be modeled in three dimensions or represented by other data. Main structural members and systems are modeled with generic standard modeling tools for the creation of 2D construction documents.

    Authorized Uses: Design Development Document level information. The model will be accompanied by general notes, connections, and typical details to define higher level information that is not typically shown in 1/8" scale plans.

    Estimating. DD level estimating along with the DDs and specifications. Conceptual estimating at best if a structural narrative is provided along with the structural BIM.

    Schedule. The Model may be used for very general project phasing such as 'existing structure' vs. 'new structure'.

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    LOD 300

    Typical Model Content. Main structural members and systems are modeled with standard modeling tools for the creation of 2D construction documents. Examples of these structural members that are modeled with standard tools in the BIM application (like Revit) are gridlines, levels, columns, beams, slabs, walls, main gravity systems and main lateral systems.

    Authorized Uses: Create Construction Document (CD) level information that is shown in plans. The model will be accompanied by general notes, connections, and typical details to define higher level information that is not typically shown in 1/8" scale plans.

    Estimating. CD level estimating along with the CDs and specifications.

    Schedule. The Model may be used for very general project phasing at the construction document level.

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    LOD 350

    Typical Model Content. Modeling beyond main structural members and systems with standard BIM application tool for the creation of 2D construction documents but at lower level of detail than would be required for fabrication. In Revit, this level of model typically requires modifying existing families or using frequent in place families to model content that is not traditionally shown on a 1/8" set of drawings. An example of such content would be in a design model where the gusset plates modeled on the braces of steel frames by a custom brace family or via in place families. Another example of LOD 350 level content would be miscellaneous steel and brick shelf angles. Modeling of structural loads would be other examples of content in this LOD that is beyond the content used to create construction plan documents.

    Authorized Uses: Detailed 3D spatial validation.

    Estimating. Construction Document level estimating.

    Schedule. The Model may be used for very general project phasing of main structural systems and some detailing scheduling.

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    LOD 400

    Typical Model Content. Fabrication level information.

    Authorized Uses: Creating shop and fabrication level information.

    Estimating. Detail estimating with fabrication level information.

    Schedule. Detail scheduling with fabrication level information.

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    LOD 450

    Level of Detail 450, Site Construction \ Erection Content is defined by the author as that content that goes beyond what is needed in the LOD 400 fabrication model to include temporary building content that is used during onsite construction. This content can be beneficial when conducting site planning and 4D scheduling of the construction.

    Typical Model Content. This could include construction items such as erecting braces, whalers, scaffolding, and cranes.

    Authorized Uses: Detailed construction coordination of the site.

    Estimating: Detailed construction estimating that includes job site level information.

    Schedule. Detailed construction scheduling for 4D scheduling.

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    LOD 500

    Typical Model Content. Content at this level must be determined on a case by case basis with the owners and facility managers.

    Authorized Uses: Uses at this level must be determined on a case by case basis with the owners and facility managers.

    Estimating. Estimating of items such as service life and operating cost at this level must be determined on a case by case basis with the owners and facility managers.

    Schedule. Scheduling building usage of items such as room use at this level must be determined on a case by case basis with the owners and facility managers.

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    Example, Tilt-Up Panel Concrete (CSI MF# 03 47 13) & Shared Models The images below show common typical details for tilt-up concrete panel construction that is classified with CSI MF # 03 47 13. A LOD of 300 would be the detail required to create construction document plans at a 1/8" scale. Historically, architects have shown the panel elevations of the buildings and as such, many structural engineers have not provided full building and panel elevations. It is traditionally the architects role to define window, door and other wall openings. The architect would normally be the one to define panel reveals, recesses and joint locations with feedback from the structural engineer.

    This would be an example of model elements that would be a candidate for a shared model. The architect would have their model with all architectural content such as interior walls and plans except for the tilt-walls. The structural engineer would have their model with all structural content

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    and plans except for the tilt-walls. The structural model would have items such as the foundation and interior steel structure and the typical tilt wall details that have been previously shown. The team would then have a third separate "Tilt-Wall Only Model" without any plans. The team would schedule which firm has the 'rights' to modify the 3rd shared model at a give time of the week. We would recommend something like a weekly schedule where the architectural team has model editing 3 days and the structural team has it 2 days. At all-times, each team would have the previous week's 'published' shared model linked into each of their models. When the structural team has the model for editing, they would be reviewing the architectural design for structural considerations. This would eliminate any duplicate modeling for the tilt-walls on the design side and would also allow all team members to take the models to an appropriate level of detail for construction documents. As the design passes into preconstruction, the tilt-wall model could be easily federated in Navisworks and coordinated with the steel detailers LOD 350 and 400 level models for pre-shop drawing review. The most important aspect of the shared model is that it allows each discipline to control the model content that they are responsible for without having duplicated content in multiple models. The table below shows how the LOD table could be used to define this workflow. Note the thirteen line items that were noted for the tilt-up concrete panels to CSI MF # 03 47 13 in the image below. Pay attention to line items that change Model Element Author from one LOD to a higher LOD when defining structural elements LOD with the table provided in this paper. Consider a shared design team model for such objects where multiple parties must control the object during the design phase of the project (typically LOD 300 or less).

    Sample of LOD of Tilt-Wall using authors spreadsheet developed with the CSI MasterFormat 2010 titles and numbers and the custom added categories. STRL = Structural Engineer Designer, ARCH = Architectural Designer, STLD = Steel Detailer, CONC Concrete Contractor, TBD = To Be Determined on a case by case basis. Example of shared model for the tilt up panel walls on a building. The image on the left shows the structural model. The image on the right Is the architectural model with interior walls, windows, dry-wall, ceilings and lights. The model in the middle is the Shared Design Model that both teams work in and use to create their construction document plans.

    STRUCTURAL

    SHARED BIM

    ARCHITECTURAL

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    Example, Wood Joist Framing

    Wood Joist systems are a class of structural content that are made of engineered products and vary by manufacturer. As such, the generic joist content in Revit looks highly detailed but is not necessarily accurate as it relates to the chord sizes and web configurations. The joist depths and weight are correct. However, there are many different manufactures who make joists and they have considerable freedom to design the web configurations, joist seats and chords. No two manufactures will be the same. There is little value in designers creating custom joists to approximate these manufactures unknowns. It is typically better to specify that the joist manufacture will provide a 3D model of their content as part of the shop drawings. This is particularly important if MEP or other trades need to run building systems through the webs of the joists.

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    SAMPLE GENERAL NOTES FOR CONSTRUCTION DOCUMENTS The following sample general notes provide ideas for construction documents to provide guidelines to the construction team to develop models beyond LOD 300. They also provide a framework for the structural design team to utilize higher level fabrication models as part of their shop drawing review. BUILDING INFORMATION MODELING

    A STRUCTURAL BUILDING INFORMATION MODEL (BIM) HAS BEEN PREPARED FOR THIS PROJECT. A READ ONLY NAVISWORKS (NWD) FILE IS AVAILABLE THAT SHOWS THE PROJECT SCOPE AND INCLUDES PHOTOGRAPHIC MARKERS OF EXISTING COMPONENTS OF THE BUILDING. THIS FILE IS AVAILABLE FOR DOWNLOAD WITH THE FOLLOWING WEBSITE INFORMATION PURSUANT TO ACCEPTANCE OF OUR ONLINE ELECTRONIC FILE TRANSFER AGREEMENT. THIS MODEL WILL BE AVAILABLE FOR SIXTY (60) DAYS FROM THE DATE THAT THESE DRAWINGS ARE ISSUED FOR CONSTRUCTION. WEBSITE ADDRESS: http://www.xxxx USER NAME (CASE SENSITIVE): xxxx PASSWORD (CASE SENSITIVE): xxxx THE FOLLOWING BIM REQUIREMENTS ARE PART OF THE CONTRACT DOCUMENTS:

    i. THE GENERAL CONTRACTOR SHALL PROVIDE A BIM SPECIFICATION TO INSURE THAT ALL SUB CONTRACTOR MODELS CAN BE FEDERATED.

    ii. THE GENERAL CONTRACTOR SHALL FACILITATE THE BIM VIRTUAL DESIGN AND CONSTRUCTION (VDC) COORDINATION PROCESS.

    iii. THE GENERAL CONTRACTOR SHALL CONDUCT CONSTRUCTION COORDINATION

    MEETINGS TO COORDINATE SUB CONTRACTOR MODELS, TO ESTABLISH PRIORITIES OF SYSTEMS, AND TO FACILITATE SCHEDULING PRIOR TO SUBMITTING SHOP DRAWINGS FOR A GIVEN ZONE OF THE PROJECT. THE DESIGN TEAM SHALL BE INVITED TO THESE MEETINGS AND NOTIFIED OF THEM TWO WEEKS IN ADVANCE OF THE MEETINGS.

    iv. EACH OF THE FOLLOWING TRADES SHALL PROVIDE DIMENSIONALLY ACCURATE 3D MODELS OF WHAT THEY WILL INSTALL THAT ARE COORDINATED WITH THEIR SHOP DRAWINGS FOR 3D SPATIAL VALIDATION WITH THE STRUCTURE AND EACH TRADE: MECHANICAL, ELECTRICAL, FIRE PROTECTION, DRYWALL, CEILINGS, CIVIL SITE WORK, PLUMBING, CAST-IN-PLACE CONCRETE, CONCRETE EMBEDS, STRUCTURAL STEEL, MISCELLANEOUS STEEL, BUILDING ENVELOPE, LIGHT GAGE COLD FORMED STEEL AND ANY OTHER TRADES THAT COULD AFFECT THE STRUCTURE.

    v. ALL 3D TRADE MODELS USED FOR SHOP DRAWINGS SHALL BE MADE AVAILABLE IN AN EXPORTED AUTOCAD 2007 DWG FORMAT AND NAVISWORKS NWC FILE TO THE DESIGN TEAM TEN BUSINESS DAYS PRIOR TO SHOP DRAWINGS BEING SUBMITTED FOR REVIEW.

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    vi. SUB-CONTRACTORS SHALL USE THE STRUCTURAL CONCRETE AND STRUCTURAL

    STEEL CONTRACTORS MODELS TO COORDINATE THE SCOPE OF THEIR WORK AND CLEARANCES WITH THE BUILDING STRUCTURE AND ALL OTHER DISCIPLINES.

    vii. 3D SPATIAL VALIDATION SHALL BE CONDUCTED SUCH THAT THE MODELS ARE BROKEN UP AND SUBMITTED BY ZONES. EACH ZONE IS DEFINED FROM FINISH FLOOR ELEVATION OF ONE FLOOR TO THE NEXT FLOOR.

    viii. THE ORIGIN COORDINATES FOR ALL 3D TRADE MODELS SHALL BE SET AS FOLLOWS:

    a. LEVEL ONE FINISH FLOOR = 100'-0" b. THE GRID LINE INTERSECTION OF GRIDS "A" AND "11" SHALL BE SET AT X= 1000'-0

    AND Y= 1000'-0".

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    Resources & Bibliography

    www.IKERD.com

    Author, Will Ikerd, email: [email protected] If interested in discussing this topic with the author or receiving updates of the LOD model, please send an email to schedule a phone call, or online GoToMeeting (or Skype for international calls).

    Autodesk Documentation & Online Help http://usa.autodesk.com/adsk/servlet/pc/index?siteID=123112&id=15115212

    SEIbim.org

    AECOknowledge.com

    Bibliography

    American Concrete Institute [ACI]. (2008). ACI Detailing Manual - 2004, Pub. SP-66 (04). Farmington Hills: ACI.

    American Institute of Steel Construction [AISC]. (2009). Detailing for Steel Constrution, 3rd Edition. Chicago: AISC.

    American Institute of Architects [AIA]. (2008). AIA Document E202 2008. Washington, DC: AIA.

    ConsensusDOCS. (2008). ConsensusDOCS 301: Building Information Modeling (BIM) Addendum. Arlington: ConsensusDOCS.


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