Bim Chat #3 - AECOM

This is the third in a series of conversations, or ‘BIM Chats’ with construction industry stakeholders with a presence in South West UK. The aim is to provide first hand insights into how the construction industry, and its project teams are engaging with BIM since the UK Government mandated BIM level 2 on public sector projects over £5M.


Following a discussion with Stuart Francis (Director) at the Constructing Excellence South West Bristol Club 2017 Annual Conference, in April 2017 Mary Bon met with Andrew Williams (Associate Director) and Philip Drozdz (BIM Technician, Building Engineering), from AECOM’s Portwall Lane Bristol office, to establish how AECOM was engaging with BIM.

Founded in 1990, AECOM is a US multinational, multidisciplinary firm and includes subsidiaries (URS and Hunt Construction Group). Headquartered in Los Angeles, it is operational in over 150 countries, has over 90,000 employees and includes a presence in South West UK with two offices in Bristol.

In the Southwest AECOM’s four key areas of expertise are Project Cost Control (PCC), Building Engineering, Environmental and Transportation, all of which engage on BIM enabled projects.

The high rate of change and other BIM adoption challenges

Andrew and Phil stated that the accelerating rate of (technological and informational) change was in their view the major challenge to BIM adoption. They elaborated on other challenges that AECOM has encountered though their BIM adoption, as follows :

1. There is a need for appropriate model checking for quality assurance purposes, both geometric and non-geometric data checking.

2. There is a need to ensure engineers are suitably trained in BIM specification and BIM data handling

3. All stakeholders need to manage client expectations

4. Proposals need to be carefully written for level 2 BIM. There are mixed perceptions in the industry what level 2 BIM actually means, and what LOD is required at each RIBA stage.

5. Refurbishment / retrofit projects have specific issues with accuracy and are dependent on laser scan point cloud quality. The conversion and usability of laser data in structural Revit models was highlighted as well as the need for a robust survey specification, including exterior and interior (including ceiling void) surveys for these projects. There is a need to clarify the level of detail / information requirements of a project’s BIM library of existing services and assets.

6. There is a greater requirement for information and design earlier on in the process. For example where previously outline scheme design information to be determine structural floor to floor heights may have been required now full 3D digital models integrated with the architectural design are often required at the planning stage.

How AECOM is rising to meet the challenges of BIM

1. BIM ¨Healthy Start¨ and Technical Practice Group

To counter the inherent challenge of operating to such a wide extent across the industry, Phil explained that AECOM rigorously develops and implements its own in-house BIM guidance entitled “BIM Healthy Start” and other technical documentation for use over project lifecycles as well as establishing a BIM technical practice group.

In its own words :

“AECOM BIM Healthy Start is a required program designed to provide the project pursuit or project management team full access to AECOM BIM experts at no cost to better understand, plan, respond, and deliver BIM projects to our clients”

and cited from this program it delivers :

  • Platform and workflow advice for starting a project using the best tools for the job, for authoring, collaboration, management & control, and delivery of data
  • Contract review and Terms and Conditions regarding safe and sound delivery of BIM Data and services
  • Training recommendations & resources to enable project teams to deliver quality BIM services
  • Technology GAP Analysis – to determine what a team may need to purchase or acquire to ensure the proper computers, infrastructure and licensing is in place for project execution
  • Access to subject matter experts and advice, as well as opportunities to acquire technology grant support for innovative and advanced solutions

The BIM Technical practice group covers three core areas:

· legal/risk aspects of BIM

· technology/IT requirements

· projects stages and change management

and its members refer to the BSI PAS 1192 suite and Construction Industry Council (CIC) documentation.

They both agreed that this was fundamental in dealing with the processing the non-graphical information and data involved in BIM, which grows as a project develops. By the time a project is handed over this is estimated to represent around 90% of the as-built information.

2. Design for Manufacture and Assembly

Andrew highlighted AECOM’s (southwest region) first real involvement in BIM in 2010 on the Bristol Royal Infirmary (BRI) £120m redevelopment project (with Laing O’Rourke as contractor) as an interesting example of a retrofit project on a tight urban site that used Design for Manufacture and Assembly (DfMA) processes and BIM. These were used in civil, structural and CDM areas alongside other AECOM services such as ecology, fire engineering and acoustics to provide a new ward block, extension to the childrens’ hospital, Bristol Haematology and Oncology Centre and a helipad alongside live medical departments which were kept operational for the full duration of the construction programme. The project was developed under the NHS Procure21 (P21) Framework and the use of Laing O Rourke’s own offsite precast concrete units manufactured in Staffordshire.


Philip explained that the information processes used to deliver the BIM model from initial design to manufacture stages in this project are shown in the workflow below:


Workflow Diagram

Credit : AECOM

Schedule Data

The schedule data was managed through ‘ideate BIMlink’, which enabled AECOM to pull raw information from the Revit model into Excel format to add and check data and then push this data back into Revit.

Schedule Data : non-graphical data typically contained within a precast element.

Credit: AECOM

Design Analysis

SCIA software was used for the design analysis and was fed into the Revit structural model. Building Services (MEP) and Architectural Models were duly shared and co-ordinated throughout the project lifecycle, and clashes checked regularly and at key stages via Navisworks. IFC files were also exported, exchanged and checked with the precast concrete manufacturer who used Nemetschek Allplan to produce the Computer Numerical Control (CNC) precast components.

3. Construction Design Management (CDM) Hazard data control.

Historically, AECOM have communicated residual health and safety risks via hazard identification notes on drawings. However, with models becoming increasingly used by clients and contractors on site it is now important that these hazards are tagged and clearly identifiable within the BIM model

4. Mentoring

Andrew went on to say that AECOM is involved in mentoring university students in order to contribute to bridging the gap between industry and education. He himself has 6-7 years involvement mentoring Final Year students at the Swansea University and this includes the BIM aspects of their REVIT digital models for their engineering design projects.

Next steps

Reflecting on what the next steps could be, Andy and Philip expressed on AECOM’s desire to ‘build on its existing successes’ in interoperable BIM, and continue to develop its capabilities in immersive technologies to further exploit the potential uses of BIM.

An example of this is the use of algorithmic modelling software in the Riyadh Metro station project that Philip has been involved in, in conjunction with the AECOM Cambridge team. This includes a wavy parametric structural roof design and combines both interoperable structural analysis and geometric design software to generate the most efficient canopy ‘gridshell’ pattern using the algorithmic modelling software, Grasshopper. His role was to create a Revit model to allow interoperability.

As was the case in the BRI project, ‘ideate BIMlink’ software was used again, but this time it allowed data to be pulled from the Grasshopper model into Excel and then pushed back into Revit to auto-populate the parameters to form the exact gridshell geometry.

AECOM is a US headquartered multinational multidisciplinary firm, and a member of Constructing Excellence South West Bristol Club.

By: Mary Bon RIBA | AEC Collaborator

Members Area
Join Today
Become a Constructing Excellence South West member today and take advantage of the benefits of membership.
Subscribe to our free newsletter
Find a member...