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Hello all, Very much a theoretical question at this stage. I came across E.C. Hambly's book 'Bridge deck behaviour' a while ago and it lists out some very useful theory/equations for modelling grillages in bridge decks. I was wondering if those same equations could also be used for modelling...

For basics on FEA, I can personally vouch for Daryl Logan's "A First Course in the Finite Element Method" (link: https://www.amazon.com.au/First-Course-Finite-Element-Method/dp/0495668257).

A couple of quick questions OP - You mentioned that the vibration requirements are for sensitive equipment. How strict are these requirements ? Are you able to recommend that all sensitive equipment be mounted on vibration isolation devices (if they're not already) ? Or are you also required...

This may be a non-starter...are GFRP bars an option ? Using GFRP with precast planks would do away with rebar corrosion as an issue for the most part. The down side is that you'll also lose all ductility and I don't believe they can be preloaded either, so no pretensioning. You'll still want a...

Here's a few items from my experience: Teach them to always ask two questions about their final design - Is it buildable ? Is it sourceable ? A rebar detail might be superbly efficient but if it can't be built then they'll need to change it. It might be good to get your firm to produce some...

Here's a trick I was taught at one point - the first mode frequency of a cantilever can be approximated as 18/sqrt(deflection under lateral UDL). This deflection is in millimeters and is for the case where a cantilever is horizontal and the UDL is applied vertically. The resulting value is in...

Great stuff @Brad805 ! One thing I'd like to check with you - does your model account for reductions in shear stiffness once the topping fully cracks at the junction between the T beams ? If the junction gets through cracks (likely if it's very thin), the only load transfer mechanisms would...

I had a crack at doing something similar a few years ago, but between Revit and ETABS using Dynamo. I'll point out some issues you'll want to keep in mind when using any sort of tool to transfer between Rhino and ETABS: Slab setdowns and minor penetrations - if the architect has modelled them...

You got me ! No room for any pesky books here. Also, not sure if I can really call it a desk [bigsmile]

@MikeManning, Good guidelines ! I went back to re-read your post and noticed that you mention your projects being high-rise. How tall are your buildings typically ? If 40 storeys or more, column shortening might also be affecting the overall deflections. A quick and dirty way to check - Are...

@ThomasH I assume this discussion is focusing on pedestrian comfort under walking/jogging alone ? If yes, then it's worth nothing that a TMD requires the structure to move before becoming really active. This will mean the structure will still achieve some accelerations under footfall before...

Thanks Brad. I've never used their sheets so can't comment sadly. They do seem to have a good variety but I reckon IDS's sheets will give most of them a run for their money. Very much so for people like me who don't like flipping through book pages for the same info haha. I sometimes use it for...

Late to the party again, but my 0.02$ here: It might be good to add some numbers to the discussion. General equations for an overhanging beam (very simplified) can be found here: https://structx.com/Beam_Formulas_024.html The overhang will hog when that term inside the bracket goes negative...

A bit late to the party, but my two cents - psychedomination I'm assuming that the equipment placement for your calcs is somewhere close to the beam center ? If so, is there a possibility to flip this back to the suppliers and have them put the equipment on spreader beams such that the...

I'm a bit late to the party but out of curiosity, Usman have you allowed for penetrations within your coupling beams in your revised ETABS model ? If the beams are deep and floor-ceiling heights are a limitation, the architect will most likely want service penetrations through those beams which...

Interesting ! Do you know if it's similar to how some FE programs provide drilling DOFs for shells? In any case, I'd still proceed with caution and not connect linear elements to the face of solids without some extra links in there.

I'll caveat my comment by noting that I know nothing about STAAD other than that it uses FEA. How have you modelled the solid element -line element connections ? In FEA, nodes of solid elements do not have any rotational fixity so if you haven't pushed your beam elements down past the face of...

I disagree. If the only loads in your models are those from self weights of the elements, then wet concrete weight in the lower CHS will not induce moments. This is because of the locked-in stress effect. We'll need details on how exactly you've modelled the wet concrete to dry concrete...

netsonicyxf, if we assume that the concrete is to be poured into the CHS at site in stages 2 and 3, then IDS is correct (and I was wrong earlier as I didn't account for the load path of the concrete in stage 2). The wet concrete weight load in stage 2 can only travel through the steel - with no...

Steveh49 might be on to something. I did a bit of digging and found this buried in midas Civil's docs: link to relevant page: https://manual.midasuser.com/EN_Common/Civil/890/Start/06_Analysis/Construction_Stage_Analysis_Control.htm netsonicyxf, might be worth checking to see if the...