BIM Implementation – Progressing from BIM 3D to 7D

There’s little doubt that the construction industry will benefit greatly from BIM technology. There are literally dozens of advantages that accurate, detailed 3D models of building projects bring. The key thing to understand is that BIM is more than just a CAD model. It’s more like a database that stores design, construction, and maintenance information, as well as any additional data related to the project.

The main benefit of BIM is the cost saving, both in the short-term and over the long-term of a project. The short-term cost savings are readily apparent – improved workflows, fewer clashes, streamlined scheduling, an easier reworking of designs, etc.

The longer-term cost benefits aren’t always so obvious. It requires a shift of focus from the initial capital outlay of a construction project to a bird’s eye view of the entire project covering the whole life-span. For instance, using BIM models to enhance collaboration between different construction contractors will simultaneously speed up the delivery of the project and increase the build quality. This will also have a positive effect on the long-term maintenance of the asset.

So, how can these benefits be realized in real life?

Is it simply a case of building a high-quality BIM model, including mechanical, electrical and plumbing details, and making it available to all construction parties? Or, is there more to it?

Before looking at the current BIM picture and the different levels of implementation, it’s useful to understand how BIM technology has developed and progressed over the years.

The Evolution of BIM

Although BIM has been available in various forms for decades, it is only in the last seven years or so that it has started to generate real interest in the construction industry. This is mainly because computing technology is now at a stage where it can handle the complexity of a detailed BIM design and yield the cost and efficiency benefits mentioned earlier.

• 1963

  The early days of BIM date all the way back to the 60’s with the advent of Computer Aided Design (CAD) software.

• 1975

  A prototype known as Building Description System (BDS) was presented that laid the foundations for BIM as we know it.

• 1977

  GLIDE (Graphical Language for Interactive Design) was created which had many of the features included in modern BIM systems. These early versions of BIM were very basic but enabled more efficient prefab construction

• 1977

  A BIM platform known as RUCAPS (Really Universal Computer-Aided Production System) was used to for the prefab renovation of Terminal 3 at Heathrow Airport.

• 1980 & 90

  saw pioneering software such as ArchiCAD take things further towards virtual 3D design and construction.

• 2000

  Revit was born.

• 2001

  Navisworks released.

Revit and Navisworks platforms have taken BIM to a new level of sophistication, especially since both companies were bought by Autodesk in 2002 and 2007 respectively. BIM has progressed over the interceding years, from a purely structural design tool to a multi-purpose, cross-disciplinary resource that assists with more than just piecing together prefab elements.

The increased complexity of BIM has led to the recognition of several different levels of BIM implementation. These range from 3D to 7D. Here is a brief outline of the criteria for each BIM level, which will be expanded upon later in this article:

• 
  A 3D rendered CAD representation of the various construction elements.
• 
  3D BIM + linked construction schedule information.
• 
  3D BIM + schedule information + cost estimation.
• 
  Includes energy simulation and analysis.
• 
  Includes post-construction information such as asset condition and maintenance requirements.

The Need for BIM in the Construction Industry

The increased sophistication of CAD and BIM technology has coincided with growing challenges in the construction industry. The following challenges have led to widespread interest in BIM adoption:

BIM Progression From 3D to 7D

Lifecycle BIM – LOD 100 to 500

This section will give an overview of the way a model changes throughout the lifecycle of a project and which parties are responsible at each stage. The stage of a construction project BIM model can be defined by the following Levels Of Development (LOD):

• LOD 100

  Initial Concept

  At this stage, the BIM model is no more than a basic representation of the physical properties of the design. Dimensions and measurements of area, volume and location are included. Surveyors are responsible for the accurate collection of survey data. Architects and designers are responsible for the creation of the model while liaising with the client to ensure that design requirements are met.

• LOD 200

  Schematic Layout

  Further definition is given to building elements with more precise size, shape and orientation details added. Non-geometric qualitative information can also be added. Architects and designers are responsible at this stage, with input from surveyors.

• LOD 300

  Detailed Design

  At this stage, the model includes specific assemblies, components, and detailed geometry. Accurate shop drawings are produced. Architects and designers collaborate with specialist suppliers to ensure assemblies are designed and modeled correctly. The design team may liaise with contractors to add scheduling information and cost estimates, etc.

• LOD 350

  Construction Documentation

  Building elements are linked, and interfaces between various systems and services are added. The model is approaching a construction-ready stage. Architects and designers liaise with construction contractors to ensure accuracy.

• LOD 400

  Fabrication and Assembly-ready Model

  All fabrication and assembly information is added, with precise geometric and non-geometric information. The designers make the model fully available to suppliers and contractors.

• LOD 500

  As-built Stage

  As-built data is added to the model for operational use and maintenance. All modeled elements can be analyzed against design. At this stage, the contractors and asset owners are responsible for the maintenance and oversight of the BIM model.

• 

Applications of BIM at Professional Level

Design Consultants – Architecture, Structural, MEP, and Landscape

The applications of BIM for design consultants are many. BIM software platforms such as Autodesk Revit, Autodesk Navisworks and Bentley’s suite of programs allow designers to build models by creating building elements or using libraries of elements (known as ‘families’).

BIM allows for a more collaborative design approach, with input from disciplines that have differing design briefs. With this approach, clashes can be detected early and rectified making the design process much smoother.

Although designers are mostly concerned with BIM levels 3D to 5D, the higher levels also benefit them as they can elicit feedback and collect data about the performance of the structure and use this to inform future design decisions.

Construction Contractors – Main and Specialized Subcontractors

Projects that implement BIM tend to use the model as the central focus. All relevant stakeholders in the project can use or amend the model as appropriate. For instance, contractors can add component information to help with future maintenance. If contractors need to raise change orders, they can send them directly to the architects through the model.

The information contained in the model is useful for most contractors involved in the actual building stage of the project and allows them to collaborate with each other far more effectively. Ideally, main contractors and subcontractors should be involved in the design process, with access to the model to allow them input into the preconstruction design decisions. This is especially important with 4D and 5D BIM where their hands-on experience can help to resolve scheduling and cost issues.

Business Owners – Developers, Project Managers, and Facility Managers

The primary purpose of BIM is the collection, collation, and management of information, both in graphical and text format. It’s more than just a design tool, and as such has managerial applications.

Depending on the project, the asset owners may be private developers, government bodies or project management teams, or may transition from one to another over time. Project managers will typically own the project until snagging is completed then hand it over to their clients. Therefore, the BIM model should be built and maintained with this in mind, providing all the information that current and future owners may need.

Project managers are also obliged to take an active role in the creation of the model, especially at levels 4D and 5D. They should also be responsible for inputting data until completion of the project and handover.

Facility managers can use the BIM model for improved management of space, reducing expenses and streamlining maintenance activities. BIM also saves a lot of time as it removes the need to manually populate separate facility management software as details of equipment location, user manuals, and technical information are already on-hand and can be directly exported to FM software.

Surveyors

Surveying agencies or contractors are sometimes overlooked in the BIM process, but they are integral to its success. A surveyor’s work is not necessarily complete upon handover of data. The BIM model relies on highly accurate data, and it also highlights where extra surveying may be required early on in the design process. Therefore, surveyors should be involved in the 3D conceptual modeling stage, being on hand to rectify survey errors or undertake extra surveying.

BIM Implementation Success Story

Kerr Hall East, Ryerson University, Canada

Kerr Hall East was constructed in the 1960s and required renovation. The building’s main functions are laboratories, classrooms, and office space. The original design and as-built drawings were unable to be found, and the hall had undergone several small-scale structural and plant renovations over the years.

The designers and project management team wanted to use BIM to the highest 7D level for this project. Here is a summary of how they achieved this:

• 01

  Built the initial 3D BIM model using 2D CAD floor plans from a recent space audit that contained base geometry.

• 02

  Added hazard mapping data, inventory tracking and asbestos mapping (4D)

• 03

  Included project planning and schedule information (4D and 5D)

• 04

  Added energy conservation estimates (6D)

• 05

  Included location of maintenance equipment (7D)

The team faced some challenges along the way:

• Data uncertainty

  Surveyors conducted spot checks to verify CAD drawings. The percentage of spot checks where site elements didn’t tally with the drawings was used as the certainty rating. The designers only included items that had a certainty rating of over 50% in the model. All equipment schedules were flagged to highlight certainty.

• Managing information transfer

  Whenever information is transferred, there is potential for loss or corruption of data. Care was taken to ensure that “push” transfers of data from the BIM model to the FM system, and “pull” transfers in the opposite direction were managed correctly and data integrity maintained.

• Controlling the progression from 3D to 7D BIM

  As there was no digital information available at the beginning of the project, care had to be taken when building the initial 3D model. Building the model could not be rushed, and adding extra information to progress to 7D had to be carried out in carefully managed stages.

7D BIM Development Framework

The Way Forward for BIM

Although BIM is a relatively new technology in the construction industry, it is advancing at a breakneck pace. We are only just scratching the surface of what is possible with BIM.

For instance, Dutch contractors are currently trialing ‘8D BIM’ which involves a fully integrated project delivery that has the aim of delivering ‘zero-carbon’ housing. This is a huge leap regarding environmental sustainability and could, in time, become an industry standard for the housing market.

There’s no doubt that BIM technology will continue to progress in the coming years and innovative and boundary-pushing projects like the Dutch one mentioned above will help to drive things forward. How long before we see revolutionary technologies such as 3D printing and advanced robotics working in collaboration with BIM models?

Watch this space!

– IndiaCADworks

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