Blast Resistant Structures 2

[Eng-Tareq]

Hello All,

For blast-resistant structures in petrochemical facilities, are the structural members still required to pass code checks (shear, moment, interactions, etc...) on blast load combinations or are they only supposed to meet the deformation limits for the response range/level (low, medium or High) determined by the client specs for these combinations?

Thank You!

 

[ThomasH]

I don't understand your question. If a member can't support the load that is applied on it, it will fail. You mention deformation limits and client specs, what are those deformation limits based on?

 

[bones206]

You have to apply code checks and ductility checks holistically. The goal is to promote plasticity where you want it to occur, while maintaining structural stability. So you have to apply code checks when looking at all the potential failure modes. For steel design, check out section 6.2 of AISC Design Guide 26 for an overview of design criteria.

 

[Eng-Tareq]

@ThomasH, I am not saying that code checks are not going to be used! I am saying that all the load combinations will be checked for your typical DL, LL, WL, etc... However, when it comes to checking blast loading since the loading time is very short we need to pass code checks for that instant where the blast loading takes place or do we just need to fulfill the deformation limits that are shown for example in table 7 of PIP STC01018 Blast Resistant Building Design Criteria. See image below

 

[HTURKAK]

Yes but My points,
-The load combinations with blast loads are with only reduced live and dead loads . Wind and seismic loads will not be combined with blast loading.
- Dynamic Material Strength is used for combinations with blast loading,
- The strength reduction factor (φ) will be 1.0 for blast load combinations .

I will suggest you to look ;

- Process Industry Practice (PIP STC01018 Blast Resistant Building Design Criteria ) and
- ASCE - Design of Blast-Resistant Buildings in Petrochemical Facilities.





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Make it do, or do without.

NEW ENGLAND MAXIM

 

[ThomasH]

However, when it comes to checking blast loading since the loading time is very short we need to pass code checks for that instant where the blast loading takes place

A blast load is time-dependent, that means that all your results will also be time-dependent. That usually means that you need to calculate the results at several time-steps and design for the worst. In my experience the maximum forces does not happen at the same time as the maximum load, there is usually a small delay.

For some cases you can use a static equivalent load but it still requies some type of dynamic analysis.