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Advertising supplement provided by American Institute of Steel Construction

By Larry Flynn

Glossary

Building Product Model. A digital information structure of the objects making up a building, capturing the form, function, behavior and relations of the parts and assemblies within one or more building systems. A building product model can be implemented in multiple ways, including as an ASCII file or as a database. The data in the model is created, manipulated, evaluated, reviewed and presented using computer-based design, engineering, and manufacturing applications. Traditional two-dimensional drawings may be one of many reports generated by the building product model (see Eastman, Charles M.: Building Product Models: Computer Environments Supporting Design and Construction; 1999 by CRC Press).

CIS/2 (CIMSteel Integration Standards/Version 2). The specification providing the building product model for structural steel and format for electronic data interchange (EDI) among software applications dealing with steel design, analysis, and manufacturing.

Logical Product Model (LPM). The CIS/2 building product model, which supports the engineering of low-, medium- and high-rise construction, in domestic, commercial and industrial contexts. All elements of the structure are covered, including main and secondary framing and connections. The components used can be of any variety of structural shape or element.

The LPM addresses the exchange of data between structural steel applications. It is meant to support a heterogeneous set of applications over a fairly broad portion of the steel lifecycle. It is organized around three different sub-models: the Analysis Model (data represented in structural analysis), the Design Model (data represented in frame design layout) and the Manufacturing Model (data represented in detailing for fabrication).

Data Management Conformance (DMC). The capability of the CIMSteel model to include optional data entities for managing and tracking additions, deletions and modifications to a model, including who made the change and when the change was
made for all data changes.

A1.2. Referenced Specifications, Codes and Standards

Add the following reference to Section 1.2:
CIMSteel Integration Standards Release 2: Second Edition P265: CIS/2.1: Volumes 1 through 4.

A3. Design Drawings and Specifications

In addition to the requirements in Section 3, the following requirements shall apply to the Design Model:

A3.1. Design Model

The Design Model shall:

(a) Consist of Data Management Conformance Classes.
(b) Contain Analysis Model data so as to include load calculations as specified in the Contract Documents.
(c) Include entities that fully define each steel element and the extent of detailing of each element, as would be recorded on equivalent set of structural steel design drawings.
(d) Include all steel elements identified in the Contract Documents as well as any other entities required for strength and stability of the completely erected structure.
(e) Govern over all other forms of information, including drawings, sketches, etc.

A3.2. LPM Administration

The Owner shall designate an Administrator for the LPM, who shall:

(a) Control the LPM by providing appropriate access privileges (read, write,etc) to all relevant parties.
(b) Maintain the security of the LPM.
(c) Guard against data loss of the LPM.
(d) Be responsible for updates and revisions to the LPM as they occur.
(e) Inform all appropriate parties as to changes to the LPM.

Commentary:

When a project is designed and constructed using EDI, it is imperative that an individual entity on the team be responsible for maintaining the LPM. This is to assure protection of data through proper backup, storage and security and to provide coordination of the flow of information to all team members when information is added to the model. Team members exchange information to revise the model with this Administrator. The Administrator will validate all changes to the LPM. This is to assure proper tracking and control of revisions.

This Administrator can be one of the design team members such as an Architect, Structural Engineer or a separate entity on the design team serving this purpose. The Administrator can also be the Fabricator’s detailer or a separate entity on the construction team serving this purpose.

A4.3. Fabricator Responsibility

In addition to the requirements in Section 4.3, the following requirements shall apply:

When the Design Model is used to develop the Manufacturing Model the fabricator shall accept the information under the following conditions:

(a) When the design information is to be conveyed to the Fabricator by way of the Design Model, in the event of a conflict between the model and the Design Drawings, the Design Model will control.
(b) The ownership of the information added to the LPM in the Manufacturing Model should be defined in the Contract Documents. In the absence of terms for ownership regarding the information added by the Fabricator to the LPM in the Contract Documents, the ownership will belong to the Fabricator.
(c) During the development of the Manufacturing Model, as member locations are adjusted to convert the modeled parts from a Design Model, these relocations will only be done with the approval of the Owner’s Designated Representative for Design.
(d) The Fabricator and Erector shall accept the use of the LPM and Design Model under the same conditions as set forth in Paragraph 4.3 with regard to CAD files, except as modified in A4.3 above.

A4.4. Approval

In addition to the requirements in Section 4.4, the following requirements shall apply:

When the approval of the detailed material is to be done by the use of Manufacturing Model the version of the submitted model shall be identified. The approver shall annotate the Manufacturing Model with approval comments attached to the individual elements as specified in the CIS/2 standard. As directed by the approval comment the Fabricator will reissue the Manufacturing Model for re-review and the version of the model submitted will be tracked as previously defined.

Commentary:

Approval of the Manufacturing Model by the Owner's Designated Representative for Design can replace the approval of actual shop and erection drawings. For this method to be effective, a system must be in place to record review, approval, correction and final release of the Manufacuring Model for fabrication of structural steel. The versions of the model must be tracked, and review comments and approvals permanently attached to the versions of the model to the same extent as such data is maintained with conventional hard copy approvals. The CIS/2 standard provides this level of tracking.