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It would depend on the relative stiffness between column and beam. Often columns are not torsionally stiff so can rotate about their axes, meaning that they are not full restraints.

You would really want to avoid that in practice. The top flange can move laterally all the way along the entire beam making it much more unstable.

The twisting is accounted for in the boundary conditions. The position of the load is accounted for by it being normal. Hence, correct - bottom flange load would be normal. However, remember that for crawl beams you may need to apply additional dynamic impact effects.

@firesun thank you very much for the insight. The crawl beam is for lifting a pump with a combined load of 100 kg at most. Is there any video about applying dynamic loads based on the code.

@@lwandilembewana5587 You can have a look at SANS 10160 as there is an entire section on crane loads. Older versions of the Red Book also have some approximate details. An additional factor in the order of 1.2 probably needs to be applied. 100kg is quite a light crawl

@@firesun thank you very much. Yes it is. You the best

😆

To get a more accurate estimate you would need to approximate shear stiffness and deformations. However, by the time you do that you lose the benefit of an approximate method and might as well do a finite element model. Hence, this is just to give a first approximation so you can check results and get preliminary sizing / sanity check on your answers. You will find in some of the older textbooks more detailed and accurate methods, from when FEM was not readily available.

Normally the girts are quite slender, and also simply supported, so will typically provide limited lateral support. Also, the column next door will often be loaded to the state so may be buckling at the same time, so cannot be relied to provide stability. However, there are detailed design methods to evaluate whether members can be considered to provide lateral support.

@@firesun thank you for your explanation

Pleasure. Glad it was useful.

A number of structural fire engineering videos are provided in this playlist: ruclips.net/p/PLcXEIpaMKkuq2PknC_UsIErB1igWxPYQ2

The girts provide lateral support about the weak axis so Ly is shorter.

UDL x span between nodes = 10kN/m x 1m = 10 kN (or half of this for the end bays)

L3 is a cantilever. On the right side it is free. On the left side it is continuous with lateral and torsional support. If assumed to be a destabilising load then we end up with K = 2.5.

You can have a look here and at the channel "Richard Walls" for various structural engineering videos.

Unfortunately that is not true. Often in practice bolts are placed within the depth of I-beams to make a base pinned. Also, if a foundation is not sufficiently large enough it will rotate resulting in the base become pinned.

The reason it does not work if the enclosure is wood is because your HRR increases massively due to the contribution of the wood. The internal behaviour, burning duration, flame lengths, etc. will all be different from a timber compartment.

Its a light board. Glass screen with light passing through it, that is picked up when you write with special pens.

The plastic kit comes from a toy shop. It is a kit for kids consisiing of balls with holes and plastic sticks. Just made it up and adding bracing from string.

they sell them in tesco

Normally the length is taken as the distance from centre to centre of supports.

It depends. If you calculate that your beam needs 35.5 minutes of equivalent resistance based on the room geometry, and you provide 60 minutes then you are fine. 60 minutes would normally represent the code requirement, whereas an equivalent design time of 35.5 min represents an updated requirement. Hence, they are requirements based on different assumptions, rather than one being pass or fail.

Sorry, my brain does not work as well in lbs and inches. Strength is often governed by member capacity and also connections. Hence, if you strengthen something you also need to ensure that the connections between members are sufficient. As a rough rule of thumb if you take the area of concrete at around 40% of the strength, say 20 MPa for a low quality concrete, and add on strength of the rebar at 60% of its yield strength you have a ballpark estimate of the capacity. 800lbs is not that much load for a steel and concrete structure, especially if there are 4 legs.

It is possible to design a structure with moment resisting frames rather than bracing. However, it needs to be ensured the structure is braced in both directions. For minor axis bending that can be a problem unless a separate frame is added. However, without knowledge of the system discussed it is just speculative.

Unfortunately the bursaries for this year have closed. However, Indian students are equally welcome to apply for bursaries when they are open. We shall advertise more next year.

The application fee is not expensive, just a few hundred rand. We have advertised bursaries for full-time studies. We don't have bursaries for part-time students as they are typically sponsored by their companies or local countries.