Having given a presentation on the digital future of engineering within underground construction at the GE’s Basements and Underground Structures Conference earlier this month, I have been considering this topic further.
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My suggestion was; that the future was bright, but while much has written on this (BIM in Principle and in Practice, Barnes & Davies, ICE Publishing being one of the better reads), not much has been illustrated on the detail from case histories, emphasising the principles. My sense is that we have only just started on this process for the below ground sector but that we are progressing down the path to the bright future.
I have a dream that the use of BIM will give greater knowledge and accuracy than is real, but suitably annotated about its limitations. Its use will reflect an appropriate level of research and investigation with each part of the basement structure and it will be clear about the unknowns, whether they are sub-contractor or follow-on design work and updated as new knowledge becomes available. This will maintain good records and delivers a final, accurate 3D record.
I see that there are projects that encourage and invest in BIM to create useful and valuable records. I single out Bond Street Station Upgrade as one of these, as having a number of good examples and cases histories, within this major Transport for London and London Underground contract. From my experience on the project, I perceive this as a good “BIM” experience.
I have been aware of developing best practice with regards BIM and the approach to existing structures, such as buildings, tunnels, shafts, redundant foundations and the like. I wrote a case history on the Bond Street project for the 5th International Conference on Forensic Engineering in 2013 that illustrates best practice and provides a checklist for future projects with regards dealing with archive material and illustrating how BIM should deal with this.
There are also obvious benefits shown to assist design and good examples for the benefits to construction when planning and phasing the work.
In the same case history, illustration of how a better understanding of the sequence and, therefore a better understanding on the assessment of the plethora of monitoring results produced these days, is shown. Here BIM greatly assists in the understanding and the speed of response to assessment of monitoring results that may require amendment to the sequence. BIM has been shown to improve all this at Bond Street, as well as on Crossrail, the London Underground upgrades and Tideway, to name just a few.
However, there are still risks that will diminish as usage increases and when detailed guidance and best practice is published. This will clarify what is meant by BIM and allow it to be better defined, and therefore better understood. The updating of the BIM model to reflect what has been constructed will also develop common, compatible or inter-changeable software that will remove current problems associated with copyright and integrity of data.
For basements and underground construction, best practice is being establish with regards existing structures and sub-contractor design. Detail guidance is being developed, but I have noticed that it is being led by the designers, although this will change as BIM executions plans become more focused and include the project promoters actual operation and maintenance requirements.
- Paul Perry is an associate director at Hewson Consulting