Do engineers over-design everything?! - Structural engineering

[@scootertheeb6172]

Material strength and stiffness are both under-valued in codes as a redundancy, in the meantime, the loads are all over-estimated to cover all possible worst cases in the codes as well. So it’s an approach of double-defences to ensure the reliability and structural performance under all cases. If the structural engineer wants to further over design the structure, that will come to an extra level of redundancy, as you said, that may turn out to overrun the budget of the owners. Anyhow, it’s up to the structural engineer to balance all conflicting factors and make the judgment.

[@sidj3018]

Hi I’m a graduate structural engineer. I haven’t experienced speaking to clients/contractors yet. Can you please give me an example answer that you could say to a client/contractor when told of an element is over designed! This will really help with my confidence of knowing what sort of thing to say.

[@MrAbdulHaque]

Excellent video, it's a coincendence I found it while I'm in a bit of a pickle! I am watching this as the client, and I have a pretty technical background in IT. I had 2 engineers spec up different beam sizes for the same opening for my rear extension. The 1st engineer spec'd up 203x203x52 UC for the main beam, I then hired a 2nd engineer due to a new architect, and he spec'd up 254x254x73 UC. I really want that beam to be concealed in the cieling void, to achieve that I need the beam size to be 203x203. I asked the 2nd engineer if it can be reduced to size 203x203, he said it can't be! The 2nd engineer provided the calculations, for the main beam, I can see a table for what looks like the utilisation with a capacity ratio column; Vertical shear 0.23, Moment 0.48, Buckling 0.72, Deflection 0.75. Does that mean the design can be improved so that the utilisation can be increased, so that I can use the beam size 203x203?

[@EverydayDazz]

Based on the utilisations it seems there is scope to use a 203UC but what weight of beam is he specifying? Difference between the two engineers is quite vast.

[@MrAbdulHaque]

@@EverydayDazz The 2nd engineer specified the main beam to be 254x254x73 UC hence the weight specified is 73?

[@EverydayDazz]

There’s a possibility to use heavier 203UC but he’ll need to do the calcs to check it.

[@MrAbdulHaque]

@@EverydayDazz Thanks I've emailed you.

[@sidj3018]

Hi great video I’m a graduate structural engineer. I haven’t experienced speaking to clients/contractors yet. Can you please give me an example answer that you could say to a client/contractor when told of an element is over designed! This will really help with my confidence of knowing what sort of thing to say.

[@qureshisiddig9274]

Useful video the ratio you have said 0.8 to 0. 9 is it for all elements or?

[@antonzangl9018]

Hi Darren! Got a question for you from a uni student just getting into structural eng. In the near future, when more and more projects incorporate greener structural materials (e.g. mass timber, and (possibly) recycled plastic concrete reinforcement, recycled/waste material utilisation etc.), I would have to guess that their 'utilisation rate' will be quite a lot lower than traditional construction materials, due to lack of long-term real-world performance data. Does this make them less viable for clients to use? Also, how long might it take until utilisation rates can increase? Cheers :)

[@EverydayDazz]

The problem with using new materials, is generally cost. Clients and contractors tend to seek the most cost effective way to build something to make the most amount of money. Being sustainable unfortunately is generally of little importance compared to making money. I have a good example where the original intentions were to be green and sustainable but the project was too expensive therefore was only made possible by using cheaper and less green options. I’ll do a video on this next!

[@nascentnaga]

the job of the engineer is to make a safe design and stay in business. the latter involves making the client happy as you note.

[@sidj3018]

Hi great video I’m a graduate structural engineer. I haven’t experienced speaking to clients/contractors yet. Can you please give me an example answer that you could say to a client/contractor when told of an element is over designed! This will really help with my confidence of knowing what sort of thing to say.

[@OkeamuteIdolorUnscripted]

Great content