Introduction. BIM-Building Information Modeling has been found to save a lot of investment and allow builders and contractors to exercise better command on the construction processes. With 6D-six dimension BIM 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 and 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-two dimension plans which are difficult for a non-technical person to understand & interpret.
Figure 1. Role of BIM in structural safety audits [Image credits: http://www.structuralauditorpune.com/about/structural-audit-header-1/]
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.
Figure 2. Typical Structural Model [Image Credit: http://www.dale-technologies.com/bim.html]
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 declaring 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 E-tabs or STAAD after which the results are summarized.
The flaw in this method: It is just too 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 stuffs 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 Building Information Modeling -BIM model with all detailing.
How can BIM enhance the process? We saw how the editing & modeling add to the cost of structural audit when with the technology we have today this task can be automated and reduced to a minimal amount. Let me explain this in the following lines.
- During the planning phase the structural detail model is prepared.
- 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.
- 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.
- The consultant will simply ask for access to the BIM model to BIM manager and access the model for structural details.
- Then he will plan the tests that are to be performed on the building.
- After performing the tests, he will update the test observations, like observed outcropping, strength observed by rebound hammer or any kind of NDT. These tests would be directly associated to the member properties in the Building Information Modeling model with attributions that include the credentials of the test auditing agent.
- Now with all the test observations, this model can simply be imported into any structural analysis software and analysed for stability. This way the time & cost of modelling and assigning properties for test can be eliminated. Next the errors can also be eliminated.
- 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 coloured 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.
Figure 3. The structural audit process cycle
Future Scopes. Now all that being said, the next level is automation and use of sensors, right now there are a lot sensor that are used in 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.
Figure 4. Sensors embedded into concrete to measure strain [Image credit: https://www.youtube.com/watch?v=3OKYtrjD34M]
Finally, AI-Artificial Intelligence 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.
Figure 5. Putting data to work [ Image credit: http://www.ritsumei.ac.jp/research/radiant/eng/robot_ai/story6.html/]
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.
Mr. Sayyed Shadaab is an Active volunteer 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 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 implementation of IT to the Construction and has worked as freelances for a number of firms. He is also a member of Student chapter for ASCE. He can be contacted through LinkedIn / mobile: +91-8888577262 / Email: firstname.lastname@example.org