Introduction
BIM has been found to save a lot of investment and allow builders and contractors to exercise better command on the construction processes. With 6D modeling, the time and the other relevant factors such as material specifications and their quantities are also included in the model itself. How can all this be made further beneficial? How can the investment made in making such a detailed model can be used to reduce the running costs and ensure that the investment is having maximum returns? The answer is to use the model itself as a background and reference in all activities of the building during the life of the structure. One of the biggest investment most companies make during the life of the structure is in Structural Auditing & Retrofitting to avoid any damage to the structure and ensure longevity, these days companies & industrial chambers hire structural consultants to perform a yearly or every 6 months or so, details on what a structural safety audit are mentioned in the next section. Generally, the reports of the audits are made in a text document format and 2D plans which are difficult for a non-technical person to understand & interpret.
About Structural Audit
Any structure constructed be it of RC or Steel sections, it loses its strength due to the utility & wear, the result is a function of numerous factors such as weather, quality of material, workmanship, curing, etc. the influencing magnitudes of these factors cannot be accurately determined as they are varying as per seasons & climate change, this makes it essential to conduct structural safety audits at regular intervals to track the health and fitness of purpose of a structure. Generally, a structural audit is conducted yearly basis.
The process involves examination of the structural elements of the building such as beams, columns, slab panels, etc. and evaluation of their strength by methods such as NDT (non-destructive testing). Generally, NDT is done by means of a rebound hammer which is quite an easy task. The physical appearance of the structure is also noted for marking the strength parameters. Then with all the experimentation and visually obtained observations analysis is done and the final report is prepared to declare the stability or fitness of the structure for the purpose. Plans are also prepared to provide a graphical representation of the test results.
Current Processes
As previously discussed it is all a pen-paper & CAD based representation work. Generally, drawings previously used drawings are referred and inferences are drawn and critical elements are determined for which tests are done. After the tests are done, the structure is analyses maybe by preparing the model in Etabs or Staad after which the results are summarized.
The flaw in this method
It is very tedious, most companies or utility buildings conduct a structural audit every year or in 6 months and every time they go through the same process the entire time. Its like they loop along every year and do the same stuff always. Users pay a huge amount for this tests but it is a part of standard safety audits and it cannot be compromised. Upon analyzing the cost of such audit one can comment that the drafting, editing & modeling of structural analysis model is what adds much of the cost. This cost can be compensated by having one standard structural model that represents the actual building, in other words, a BIM model with all detailing.
How can BIM enhance the process?
We saw how the editing & modeling add to the cost of the structural audit when with the technology we have today this task can be automated and reduced to a minimal amount. Lets me explain this in the following lines.
1. During the planning phase, the structural detail model is prepared.
2. During the execution phase, the structural detail is verified and modifications are updated in the model itself.
Note that the model is containing all the loads of the occupants, the dead load, the live and etc. applicable during the design phase.
3. Now the building is ready for use by the occupants. And is serving as per the design criteria and the structural audits are now planned. So suppose it is the first structural audit.
4. The consultant will simply ask for access to the BIM model to the BIM manager and access the model for structural details.
5. Then he’ll plan the tests that are to be performed on the building.
6. After performing the tests he’ll update the test observations, like observed outcropping, strength observed by rebound hammer or any kind of NDT. These tests would be directly associated with the member properties in the BIM model with attributions that include the credentials of the test auditing agent.
7. Now with all the test observations, this model can simply be imported into any structural analysis software and analyzed for stability. This way the time & cost of modeling and assigning properties for the test can be eliminated. Next, the errors can also be eliminated.
8. Once the tests are done the results can be exported and with the help of a developed algorithm can be overlaid on the BIM model itself along with the stress contouring to provide the stability information. The colored contouring can make it simple and efficient to express the stability of the member and command necessary actions. Usually performing the tests and then preparing the report can take weeks of time and a huge amount of investment with BIM this can be a work of a couple of days and can save huge investment from companies having large structures.
And now the points 3-8 will be re-iterated for other times of structural audits. Much simpler and the history of the members changes in strength can be recorded to provide important information such as design failure or efficient loading considerations.
Future Scopes
Now all that being said, the next level is automation and use of sensors, right now there are a lot of sensors that are used in the construction sector that relay important information such as stresses and deflection of the structural elements. All that remains is to link those sensors and then fire-up an algorithm to work and process that strength related data. This can sound a bit costly at the initial phase but in the long run, it’ll be much beneficial and can even be useful in times of disasters particularly earthquakes for the building safely.
Finally, AI comes into the picture, till now there was stress information, magnitude of disaster and also the strength parameters with sufficient samples of events AI can automate the disaster relieve works such as adjusting the frequency of dampers to suit the change in loads in order to reduce the motion of the buildings and save it from rupture or complete failure. It can also predict possible maintenance procedures that can be performed on the structures.
Acknowledgement
I express my heartfelt gratitude to Amarnath CB for his immense help and support and for being highly motivating and instrumental for this endeavor.
About the Author
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Mr. Sayyed Shadaab is an Active Member at India BIM Association. He is a Co-founder and blogger at iecivil.com, he shares innovative technical knowledge on his blog. Having published a few research papers in reputed journals on diverse topics from Solar power to the implementation of radio waves in construction and Accident Identification. He is tagged as ‘The Engineer for the Digital Civilization’, graduated Bachelors in Civil Engineering from Savitribai Phule Pune University. He’s obtained higher schooling in Bifocal sciences and Electronics. He’s been working on the implementation of IT to the Construction and has worked as freelances for a number of firms. He is also a member of the Student chapter for ASCE. He can be contacted through LinkedIn / mobile: +91-8888577262/ Email: sayyedshadaab@iecivil.com
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