Keywords

Building Information Modeling; UK government BIM aims; BIM in practice; savings with BIM; Tekla Structures; Tekla BIMsight; industry transfer standards; nD information; reference models

Introduction

Technology to access and control construction information is constantly changing and the relevant information is required to be available on various devices and platforms. For example even preparing this chapter has involved storing information on the ‘Cloud’, interfaced from a smartphone, various laptops, and a PC, all on different platforms and this is just for controlling text. The construction industry is moving to digital integrated design team project delivery, with all of the necessary information being available at any stage of the contract and beyond. Each project design team can be formed from many different players depending on the actual work requirements and content. For example, a design team could include the client; architect; engineer; MEP (mechanical, electrical, and piping); contractors; etc. One of the processes that support these developments is Building Information Modelling (BIM). BIM is not a single 3D application; it is a process that streamlines the product model content and delivery.

It is worth concentrating on the ‘Information’ part of BIM before addressing the BIM process. Information always needs to be collected and contained in a physical object or system. In history this could have been on a stone tablet, or nowadays a book or ‘project library’ would be made available to the reader or viewer. This really is the same with BIM, however, the whole project information is not just available as a great volume, but broken down to object-level nuggets of information for ease of reference.

A product model can be built or defined with a 3D or 4D application, where the latter is the 3D information which also encapsulates the time information. This can also include manufacturing information, start and completion dates, maintenance information, and even the required special demolition procedures, as the model can support the full life cycle of the building or project. However, the BIM model is not limited to just 4D information, as costing can be included, which is sometimes referred to as 5D information, or really anything that the user wants to track (nD information) and control.

Sometimes BIM is thought to be just another service that provides users with instant online access to an ever-increasing stream of constantly evolving, instantly updating digital data. However, if the processes are in place then real project control is possible. Many times it is said that: ‘Nowadays to change a pump physically on a building site is relatively simple. However, changing all of the 3D models, drawings, sketches, specifications etc. is the hard and time-consuming part’. Adopting the BIM process will revolutionise this, as the information has only to be changed once, with the authoring application, after which the rest of the design team members can simply reinsert the new ‘reference model’, with all the latest information, ensuring all the models are up-to-date.

History of BIM

2D drawing systems have been used since the early 1990s and were really used only as ‘electronic drawing boards’, copying and pasting details or ‘blocks’ to reproduce drawings quicker than the older manual processes. However, as far as interoperability was concerned there were no advantages. Various applications allowed different drawings or blocks to be imported into the working drawing using some form of ‘X-Ref’ options, which really was the start of the reference model concept.

General Computer-Aided Design (CAD) tools were used for a while, leading to bespoke solutions which were developed to suit each industry or design team member’s requirement. For example, tools used by architects would require different functionality from the toolkit required by engineers. Also a structural engineering application would have different drawing requirements from a Mechanical Electrical and Piping (MEP) solution. It is interesting to note that in many companies the technicians will produce the drawings, with engineers just resolving typical project sections or sketches.

In the building and construction sector, ‘Information Modelling’, is normally defined as the computer representation of a building or structure, including all the relevant information required for the manufacture and construction of the modelled elements. The elements or objects are required to be intelligent and should therefore know what they are; how they should behave in different circumstances; and their own properties and valid relationships. A simple example of this would be the reinforcement in a pad foundation. If the foundation size is modified then the embedded reinforcement should update and reposition itself accordingly. This is very different from a computer-generated model, which has been constructed for purely visualization purposes, where every objected is a non-related element.

The structural steelwork industry is always recognised as the lead sector in 3D modelling solutions and their developments can be traced back over the last 20 years with applications such as the forerunner of Tekla Structures. This type of application allowed the 3D steel frame to be modelled and the connection applied by the use of user-defined macros, which allowed the automatic production of general arrangement drawings, fabrication details, and then, after a few more years, the development of links to CNC (computer numerically controlled) machines, for the cutting and drilling of steel sections and fittings.

Once the 3D modelling technology was extended to include Parametric Modelling (true solid objects) then clash detections systems were able to be developed. Hard or soft clash detection allows applications to identify any possible material overlapping conditions or objects existing in the same space.

Nowadays Globally Unique IDs or Globally Unique Identifiers (GUIDs) are available in most applications, which are unique strings usually stored as a 128 bit integer, which is associated with the objects. The GUID is used to track the objects between applications for change management. Some systems allow the support for internal and external GUIDs. The term GUID usually, but not always, refers to Microsoft’s Universally Unique Identifier (UUID) standard.

From the start of BIM, only drawings and reports were made available, as the actual BIM model was always confined to the office where the more powerful computers were situated. However, as computers have advanced, the models are now accessible on laptops and, over the last few years, even on tablets.

What Is BIM?

So what is BIM? It could simply be defined as rapidly evolving collaboration tools that facilitate integrated design and construction management. The importance of ‘I’ in BIM should never be underestimated, as this becomes a project or support for the company’s enterprise framework and not just a means for ‘building models’. This information means that more work is done earlier in the project to support green issue concepts, as less waste saves both materials and energy.

BIM enables multidimensional models including space constraints, time, costs, materials, design and manufacturing information, finishes, etc., to be created and even allows the support for information-based real-time collaboration. This information can be used to drive other recent technologies including city-sized models, augmented reality equipment used on site, radio-frequency identification (RFID) tags to track components from manufacture to site, and even the use of 3D printers.

It may be useful to consider the players who would want to have access to the BIM models. Not limiting the list they could include the clients, local authorities, architects, engineers (structural, civil, and MEP), main contractors, steelwork and concrete subcontractors, formwork contractors, and all site personnel. Until recent years BIM was only available as a solution for architects, engineers, and steelwork contractors, leaving everyone else just to work with 2D drawings that may be industry-specific but not totally readable without knowledge of that environment.

Various references have been made to the architects’ BIM model or the structural BIM. However, they really are the same, as the boundaries between their models and their content are lessening all of the time. Architects’ BIM models will include structural member sizes, but the models that they produce do not normally need to include the material grades, reactions, and finishes. Where the model is produced by the steelwork contractor, it will include at least the manufacturing details and all the information necessary to order, fabricate, deliver, and erect the members. The MEP contractor could also define the site fixings on his versions of the model, as the contractor will want to know when the member will be on site, where it will be fixed or poured, and how much the item costs. The client’s view of the same member would be for control and for possible site maintenance. For this reason various models are created in the ‘best-of-breed’ authoring applications and shared with other design-team members as reference models, which are normally in the form of Industry Foundation Class (IFC) files for all structures except the plant and offshore markets, where CIMsteel Integration Standards (cis/2) and dgn format files are the dominant interoperability formats.

It is so much easier to work with a BIM model and to explore the building in 3D with rich information, than looking at hundreds of drawings and having to understand the industry drawing conversions. Now users can simply click on an object and obtain all the information that they require either through the native object, if in the authoring application, or through the reference model or even from a viewer or collaboration tool.

UK Government Recommendations

The UK and other governments have expressed support for BIM over recent years. However, in March 2011 the UK government published a BIM Strategy Paper. In fact the UK government has made it clear that BIM needs to be adopted on all of their projects within the lifetime of the present parliament to save the model objects from being rebuilt many times within the same project by different design team members.

The aims and objectives of the working group were:

The general recommendations were:

The report also defines the project BIM maturity levels, from Level 0 to Level 3. As a quick summary Level 0 is where just CAD tools have been adopted; Level 1 is where 2D and 3D information is used to defined standards; Level 2 is where BIM applications are used with fully integrated model collaboration; and Level 3 is where BIM models are used for project/building lifecycle management. See Urn 11/948, which is a report commissioned by the Department of Business, Innovations and Skills, first published in July 2011, for further information.

What the UK government wants is:

How BIM Is Applied in Practice

If a BIM model is being enhanced on the authoring application, it is normally referred to as a physical or native model, which can be enhanced using normal authoring tools. If the model is to be fixed by one design team member, then an IFC file or other reference models are normally adopted where objects can be commented upon but not changed by other members of the design team.

Linking Systems through Open .NET Interfaces

Sometimes using industry standard files is not appropriate when tight linking of applications is required. For example, a user may want to share design information between a modelling system and say A&D applications, management information systems (MIS), enterprise solutions, connection and fire design systems, project management systems, or planning systems.

In such a case the objects, a simplified form of the object, or just the object attributes, can be passed between systems using the Open .Net interface as defined above. This same interface could also be used for model transfer or for repetitive processes such as drawing and report creation.

Tekla BIMsight

Tekla BIMsight has been written by the Tekla Corporation, which is a Trimble company, and is a free BIM collaboration tool which is available for anyone to download and install. It is also an easy-to-access application that presents the complete project including all necessary building information from different construction disciplines. It is also much more than a viewer as one can communicate using the model with anyone, not just Tekla Structures or other BIM software users.

With Tekla BIMsight one can:

For interoperability the file formats supported by Tekla BIMsight currently are IFC (IFC, IFC XML, and IFC ZIP), dwg, dgn, and xml.

Savings with BIM

It is always hard to establish Return on Investment (ROI) and project savings with regards to any software systems. However, as the BIM project is created within the memory of the computer before any materials and site personnel’s time are involved change is cheap. Various report and white papers regarding the cost of change and constant remodelling was one of the reasons for the UK government’s BIM initiative.

Sample BIM Project – Alta Bates Summit Medical Centre - by DPR Construction Inc.

The addition to the Alta Bates Summit Medical Campus (ABSMC) is a $289 million, 13-storey patient care pavilion and future home of over 200 licensed beds and the facility is due to open in January 2014. DPR’s highly collaborative Integrated Project Delivery (IPD) team was faced with many challenges. The use of Tekla Structures and Tekla BIMsight has grown significantly since the start of construction in 2010. Modelling scopes within Tekla Structures includes Structural Steel, Cast-in-Place (CIP) Concrete, Reinforcing Bar, Miscellaneous Steel and Light Gauge Drywall Framing. See Figures 52.1 to 52.7.

Seismic design requirements set forth by the Office of Statewide Healthcare Planning and Development (OSHPD) in addition to a hybrid steel and concrete shear wall structure required in-depth coordination between rebar and steel fabrication models. This coordination effort between multiple trade partners would not have been achieved without the use of this highly collaborative and detailed BIM platform. Since subcontractors Herrick Steel and Harris Salinas Rebar were both detailing with Tekla, it was very useful to provide the rebar detailer with the steel model during detailing to identify constructability issues with anchor bolts, stiffener plates, and other connection details that were not shown in the engineering design model.

More recently, the ABSMC Project has implemented the concept of Dynamic Detailing within Tekla Structures on both the reinforcing steel and drywall framing. By referencing in the structural steel Tekla model along with IFC models of the MEP&FP systems, Harris Salinas rebar and DPR Self-Perform Drywall were able to identify conflicts during the process of modelling, as opposed to the traditional method of modelling in a silo and having to rework the modelling after clash detection. This workflow results in a more efficient, streamlined workflow with fewer chances for modelling errors (see Figures 52.1 and 52.2).

The DPR Self-Perform Drywall detailer, Robert Cook, has developed an efficient workflow to detail the rebar using multiple custom components. Robert Cook is also creating drywall framing assembly spool sheets that can be printed to 11” × 17” or viewed on an iPad to help the site team to increase efficiency and quality while reducing rework. As all the ductwork is fabricated and assembled directly from the model, DPR drywall is now able to install framing around the duct and pipe openings prior to MEP installation and be confident that the framing is in the right location to align with the prefabricated ductwork and piping.

In addition to Tekla Structures, Tekla BIMsight has been used to convey differences between site conditions (see Figure 52.3), and the design model related to the exterior skin and expansion joint design. The Alta Bates project requires seismic expansion joints where surrounded on three sides by the existing hospital campus and around a five-storey pedestrian bridge. The comment tool, dimensioning tool, and photo attachments were used to convey coordination and constructability issues to the designer, fabricator, and installer.

Sample BIM Project – The National Museum of Qatar (Arup)

The National Museum of Qatar in Doha (see Figure 52.8) is the flagship project for an important series of cultural and educational projects which have being commissioned by the Qatari government. The project, which drew inspiration from the desert rose, has now started on site and has been in the planning phase since 2008. The desert rose is a crystalline formation found below-ground in saline regions of the desert. When imagined as a building, the result is a four-storey, 300 metre by 200 metre sculpture of intersecting discs that are up to 80 metres in diameter.

The evolved structural solution consists of radially and orthogonally framed steel trusses, supporting fibre-reinforced concrete cladding panels to create the required aesthetic and performance characteristics of the building envelope.

Interoperability and Principle Industry Transfer Standards

3D interoperability between various building and construction applications are generally achieved through industry standard formats such as dwg, DXF, SDNF, cis/2, and IFC with the older systems being listed first. Other bespoke links have been adopted in the past based upon XML (extended mark-up language), which is basically is an extension of HTML and which is used for creating websites) or special file formats. Excel sheets have also been used in the form of reports or to enhance the various applications. It is generally accepted to adopt the full BIM process and then only IFC files are advanced enough to support all of the objects that are in building models.