Bim Engineering: The New Paradigm

In the structural design world, nothing has shaken the ground quite like BIM engineering: Building Information Modeling. Design practices for construction of large scale structures have been fundamentally the same for thousands of years: Representational drawings have been made to describe the ultimate product. Two fundamental weaknesses have always been inherent in the system: Depicting the eventual real world, 3D object in traditional design requires multiple drawings, masses of specification sheets, redundant work and a higher possibility of error. Secondly, this representational method couldnt fully utilize the powerful computational capabilities of the computer. BIM engineering is a paradigmatic change from architectural CAD (Computer Assisted Design) based designing. Most simply, CAD is 2D and BIM is 3D. CAD is representational, static, geometric line drawings that have weight and dimension, their only data. BIM is virtual modeling: it creates visual objects in 3D that contain, using databases, all the data about the object that the architect, structural engineer, MEP engineer, builder or owner could ask for or want. And these objects are adaptive, dynamic and complexly interrelated. This is the real power of BIM engineering, what is known as parametric modeling.

In this concept, absolute values for objects in the model are replaced by relative parameters. Once these values, geometric, analytic or descriptive, are defined, they can be easily adjusted by an engineer or architect, allowing for:

Rapid designs. New models can be easily constructed from previous objects.

Facilitation of complex geometries with the use of object templates and parameter formulas.

Comparison of design alternatives by altering object parameters.

The assemblage of repetitive, iterative structures, which are easily rendered with its database-driven user libraries of frequently used components: walls, joists, beams, trusses, columns and foundations.

All of the objects of the BIM engineering virtual models are rich with data: size, weight, material, tensile strength, etc.., as well as being dynamically linked to all the other objects in the model and their properties. Geometry, spatial relationships, geographic information and light analysis are also captured, as well as the properties and quantities of building components. If you change the width of a door in a BIM model, it affects the size, shape and carrying capacity of the wall, the mechanicals running in the wall, and any structural members that might somehow be affected by the change. The model is a completely integrated object, and thus the design process is able to virtually manipulate the many characteristics to achieve the final goals of the design. Since the process is global and automated, the rippling of changes throughout the model can drastically reduce mistakes in set coordination. Also, drawing changes can automatically update schedules, sections and details. The extraction of many different views of a building
model is also one of the inherent properties, and advantages, of the database. While the 3D visuals are certainly the Wow factor of BIM engineering, it is the parameterization of values that is the powerhouse behind this new technology.

BIM is also paradigmatic in two other ways. One, it causes a sharing of information between all the members of a project, architect, engineers, construction managers and owners, in ways that are unprecedented and pave the way for cheaper, faster, and safer projects. Clash detection amongst the different engineering disciplines is reduced in scope and highly accelerated. Errors and change orders at the shop drawing level can be dramatically reduced as modeling allows for revelation of spatial conflicts that 2D drawings cant. Secondly, BIM engineering becomes a central place to manage and concurrently work on all aspects of the building life cycle processes, in many ways becoming the ultimate product lifecycle management (PLM) tool in the design and construction industry. Since BIM engineering allows for materials specifications as part of the model, real-world values, including price and structural/environmental characteristics, can now be judged at the design phase, reducing or eliminating problems or uncertainties usually encountered during the construction phase. Complementing this is the fact that construction managers can input changes, or contemplated changes, that take place during project delivery, allowing for quick analysis and keeping the model comprehensive and authoritative. This then pays forward to the building owner, who is presented with a powerful and authoritative tool for building management. The ability to evaluate and analyze maintenance or repair needs can be greatly enhanced with the owner having a BIM engineering model at hand.

The history of BIM engineering dates back almost 30 years, to 1982 and Graphisofts development of ArchiCAD, a virtual building solution for the Apple Macintosh. Brought to market in 1986, it was the first personal computer based product capable of rendering parametric 3D models.


For more information about ODonnell & Naccarato BIM engineering services:

Dennis Mordan, PE
215-925-3788
http://www.o-n.com/