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[alpa_sheth]

Dear Sefians,

We have had a very difficult last week seeing a terrible air crash. It makes us realise the fragility of our lives. As they say, Carpe Diem- Seize every moment of your life to do all the good that you can.

But amidst the doom and gloom I was so very pleased with the absolutely stellar performance of the Hostel building on which the Airplane fell. The building suffered a HUGE impact load, a Blast load too,  because the airplane crashed on the building and through the hostel building,  carrying 1.25 lakh litres of fuel which led to a huge inferno with temperatures reaching over 1000 deg C.

Despite all this, the building did not lose its integrity. No major structural vertical element (from what has been accessed over the net) collapsed and caused progressive failure of the building. The building did not collapse.  Imagine the additional damage and deaths that could have been  caused, if it had.  Sure, the walls where the plane punched through, gave way. Some bits of slab gave way. This was the least that should have happened. But these were all localised failures. The building withstood it all, the impact, the fire without losing its load carrying capacity.

Compare this with other structures that have suffered  blast impact. We're seeing a war in live action as I write this and towers are falling like ten pins in  the countries at war. Also recollect another incident when two airplanes flew into two large towers in the most developed country in the world and caused a progressive failure. Not a valid comparison, I agree,  but they were similar incidents.

I do not know who had designed the hostel building and who had constructed it. Both the agencies deserve to take a bow. Rarely are people celebrated for what performed well and what did not go wrong. I think it is time we acknowledged the unseen heroes.

My  SALUTE to them, whoever and wherever they are!

warm regards,
Alpa Sheth




Note: Visuals sourced from public media sources on internet, acknowledged where source is known.

[pramod_joshi]

This is Pramod Joshi civil consultant.

I read your article on the medical college buildings performance at the plane crash. As observed by you, the buildings have stood all the criterion of safety requirements. Though there was a huge fire, the buildings were having more than two hours of fire resistance. None of the building collapsed. The buildings sustained huge impact of the airplane crash .

When all the media and people were concentrating on the crash, I appreciate you were reading "between the lines".

This is the true quality of the structural engineer who breathes, lives in structural engineering.

Believe me. When a peacock is dancing with its full feathers spread, I always feel that this is the best case of material and section selection for such a long cantilever. Imagine what fixity the peacock must be generating at his back to hold so many feathers vertical from horizontal. We feel the peacock is dancing, but the peacock must be shivering because of the fixity created.

People look at large spread coconut, tamarind and banyan trees as greenery, I feel the structural engineering in the trees.

This has raised one question in my mind. Should we think about this air crash factor in structural design for the buildings in the funnel of aero plane landing and take offs?


--

[sunilgorle]

Thank you for your insightful note and kind words.


Indeed, the resilience shown by the medical college buildings under such an extreme and unfortunate event is a testament to the robustness of current structural engineering practices, especially in fire resistance and impact tolerance. While the event itself was tragic, it also highlights how well-designed structures can mitigate catastrophic outcomes.


As for considering airplane crash loads in routine building design -- your question is pertinent, especially in the context of buildings located in the landing and takeoff funnels of busy airports. However, as you rightly pointed out, such events have an extremely low probability (in the order of 1 in a million or lower), and current design codes globally reserve such exceptional load considerations primarily for critical infrastructure like nuclear facilities, defense establishments, or very high-risk occupancy zones.


Nevertheless, your analogy of the peacock and trees reflects the beauty of structural engineering -- how nature constantly teaches us about balance, form, and efficiency. It is a reminder that our understanding of forces, fixity, and stability can -- and -- should extend beyond textbooks into the world around us.


That said, as urbanization encroaches closer to active flight paths, it may be worth considering limited impact-related provisions in sensitive zones -- perhaps not a full structural redesign, but detailing strategies for compartmentalization, fire resistance, and evacuation safety.


Appreciate your reflections -- this is the kind of thinking that keeps our profession both grounded and inspired.




Sunil Gorle
Structural Engineer




Tue, 17 Jun, 2025, 12:09 pm pramod_joshi, <forum@sefindia.org (forum@sefindia.org)> wrote:
[quote]            This is Pramod Joshi civil consultant.

I read your article on the medical college buildings performance at the plane crash. As observed by you, the buildings have stood all the criterion of safety requirements. Though there was a huge fire, the buildings were having more than two hours of fire resistance. None of the building collapsed. The buildings sustained huge impact of the airplane crash .

When all the media and people were concentrating on the crash, I appreciate you were reading "between the lines".

This is the true quality of the structural engineer who breathes, lives in structural engineering.

Believe me. When a peacock is dancing with its full feathers spread, I always feel that this is the best case of material and section selection for such a long cantilever. Imagine what fixity the peacock must be generating at his back to hold so many feathers vertical from horizontal. We feel the peacock is dancing, but the peacock must be shivering because of the fixity created.

People look at large spread coconut, tamarind and banyan trees as greenery, I feel the structural engineering in the trees.

This has raised one question in my mind. Should we think about this air crash factor in structural design for the buildings in the funnel of aero plane landing and take offs?


--        --auto removed--

Posted via Email

[nurat]

In my opinion there must be some norms and restriction for  height of the Buildings  near the Airport I.e close to landing and  takeoff funnel  I think NBC too study and incorporate this  
On Tue, 17 Jun 2025, 13:36 sunilgorle, <forum@sefindia.org (forum@sefindia.org)> wrote:

[jijipanickerk]

Yes, truly incredible. The agonies and miseries brought in by the aeroplane crash is unparalleled and no Indian could forget it in their life. Still, one thing all Civil/Structural Engineers would acknowledge and appreciate is the structural integrity of the building into which the plane crashed; we see the structure withstood the impact and thermal load. The design and construction deserve accolades.


Regards,
Er.Jiji Panicker K. 


On Mon, 16 Jun 2025 at 18:10, alpa_sheth <forum@sefindia.org (forum@sefindia.org)> wrote:

[bhsolanki]

Indeed its true piece of structural engineering and work execution quality control both as per drawings and specifications.

people on social media are doubting on 9/11 attack on USA's twin tower, that how was its quality.

we all know structural failure reasons of 9/11 attack but just putting here people are appreciating our engineering on one sense.

[bsec]

Dear Alpa
I truely appreciate your article on Medical College Building. Your clinical observation wearing a structural engineer's hat ..."Though there was a huge fire, the buildings were having more than two hours of fire resistance. None of the buildings collapsed. The buildings sustained huge impact of the airplane crash" is just out of the box. Hats-Off to you.  Now that this point is raised by you, SEFI members would be keen to know whether any individual / firm is assigned the responsibility to audit this building and we would be keen to know the outcome. It would be great if any academic institution comes forward to do a bit of research on this building to analyse how the impact of this aircraft was absorbed by this building? Is the building overdesigned? what are the features in the building that saved it from global failureBest Wishes


Alok Bhowmick

President - Indian Association of Structural Engineers (IAStructE)
FNAE, International PE (India)

Delegation Head (India), ING-fib 







Managing Director


B&S Engineering Consultants Pvt. Ltd.
315-316, Vishal Chambers, Sector 18, Noida; U.P - 201301
Tel: +91-120-4570703; 4310433; Mobile : +91-9811175255


·       Winner of “IEI Industry Excellence Award 2022â€�

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On Mon, Jun 16, 2025 at 6:08 PM alpa_sheth <forum@sefindia.org (forum@sefindia.org)> wrote:

[pvsrao]

In the recent Plane crash accident at Ahemdabad airport, becomes a  heart breaking incident . The  Air Plane crashing  in to the medical college buildings is of deep tragic and severe painful feelings of every human being. Besides, as Civil Engineers, its really an astonishing fact to see that the  building could have sustained the severity of impact, blast and extreme instantaneous hot exposure. Normally at 1000 degree temperature, as per the Research findings, the concrete may be susceptible for crushing to pebbles. But the present hostel building, as seen from visuals, did not yield to collapse fully, with stood high temperature and impact,  though localized damages took place, which is enviable. Great performance of concrete . Low height ( G+one or two) of the building may also have contributed for non collapse.  The then quality of constructions and all the team behind the building design and execution shall be appreciated.

The analysis seen in the so far posed articles, by the well versed seniors SEFIANS, will surely guide the researchers on this issue.

[Jeevan Patgaonkar]

Very well pointed out the structural design engineers role and whoever has supervised it. 
They appear to have done their job perfect. 

On Tue, 17 Jun 2025 at 8:16 AM, bsec <forum@sefindia.org (forum@sefindia.org)> wrote:

[quote]            Dear Alpa
I truely appreciate your article on Medical College Building. Your clinical observation wearing a structural engineer's hat ..."Though there was a huge fire, the buildings were having more than two hours of fire resistance. None of the buildings collapsed. The buildings sustained huge impact of the airplane crash" is just out of the box. Hats-Off to you.  Now that this point is raised by you, SEFI members would be keen to know whether any individual / firm is assigned the responsibility to audit this building and we would be keen to know the outcome. It would be great if any academic institution comes forward to do a bit of research on this building to analyse how the impact of this aircraft was absorbed by this building? Is the building overdesigned? what are the features in the building that saved it from global failureBest Wishes


Alok Bhowmick

President - Indian Association of Structural Engineers (IAStructE)
FNAE, International PE (India)

Delegation Head (India), ING-fib 


https://ci3.googleusercontent.com/mail-sig/AIorK4zedOX8shgJTocDUFxAAAJmE3fssQ9xFT2hNQp03qMlo-oQgePBqx0tHFL-Yojro2Jd02It1Sc-OQIA">




Managing Director
https://ci3.googleusercontent.com/mail-sig/AIorK4xIQz5Y9deaydhfFEyd1WZdwe2qvWfVEhs4A1LQCnPwS2YbLNH03AAhrWK4hUIC_tJQOheK8-8">

B&S Engineering Consultants Pvt. Ltd.
315-316, Vishal Chambers, Sector 18, Noida; U.P - 201301
Tel: +91-120-4570703; 4310433; Mobile : +91-9811175255


·       Winner of “IEI Industry Excellence Award 2022â€

·       CEAI National Award winner for “Excellence in Engineering Consultancy Services†for 2017, 2018 & 2023









On Mon, Jun 16, 2025 at 6:08 PM alpa_sheth forum@sefindia.org (forum@sefindia.org))> wrote:

      --auto removed--

Posted via Email

[shenoy]

Heartfelt condolences to the near and dear who are affected by the Crash.

I do really appreciate the mention  of the performance of the building structure that did not collapse , subjected to the impact and the blast. If the structure had collapsed, the death toll would have been more, definitely.

But before patting the designer and the builder for this 'unexpected’ performance of the building, I feel we need to look at this from a different point of view. We have our set procedures for the design of buildings to resist the effects of natural disasters based on our strategy of mitigation, probabilistic theories, historical evidences. In no case we design the buildings, making them disaster proof. This means saving life, giving time to vacate the invaluable life/assets, even if the building is useless after the disaster.

There is no way a building can be designed to resist a man made disaster/ unfortunate disaster like the one happened in Ahmedabad, as the forces due to impact can not be quantified in advance, nor can it be assumed, based on previous experience. So, when we pat the structural designer of this building, are we glorifying his ability to forecast the forces and design the building accordingly ? If done so, how could he assume the forces?
Does it mean the Structural designer of the building is more brainy than the structural designers of the World Trade Center which collapsed when a similar incident happened? Are we giving a message to young Structural Engineers that you start assuming huge extra loads, assuming a plane is going to fall on the building and  better consider a huge factor of safety in your design?  and What is the Factor of safety that will qualify for a pat if such an incident happens?

If The structure that did not collapse has been built merely satisfying the clauses of IS codes that do not suggest any quantification of the effects these kinds of impacts, I would say, our codes are very conservative.

On the other hand if the structure absorbed a part of the impact load/ blast and the saved the plane from splitting/ or saved the passengers, and if the structural designer had consciously designed the form/members/ of the building, I would definitely pat him. Otherwise, I would suspect that the building was thoroughly overdesigned, spending the owner's money, luckily that has shown some good results.

So, to earn a pat, let our young structural engineers not  overdesign the buildings with loads not quantifiable, assumptions not 'justifiable', and scare the owners of probable crash of planes on their buildings ! Afterall, all buildings are not designed as shelters !

- Dr. Premanand Shenoy