topic Re: Analysing and detailing capping beam on piles in Robot Structural Analysis Forum

Analysing and detailing capping beam on piles

onayohob23 — Tue, 26 Sep 2023 08:05:56 GMT

Hello all

I'm trying to analyse and detail a RC Capping beam which will need to cantilever approx. 8.0m (i.e. soil is excavated in front of the secant pile wall/capping beam but no temporary props will be installed to support the capping beam).

Please see the PDF drawing attached for clarity.

I've analysed the capping beam by modelling the unexcavated areas as spring supports at reinforced pile locations (every 700mm centres), with spring stiffness corresponding to soil modulus of 10000kN/m2 (=7000kN/m).

The analysis results show moments in the region of 1700+kNm and will need to be heavily reinforced, with multiple H32 bars along the rear face of the capping beam. Unfortunately, Robot is not allowing me to detail these bars.

Can someone please shed some light on what I'm doing wrong? RTD attached.

Thanks

Re: Analysing and detailing capping beam on piles

Simau — Tue, 26 Sep 2023 10:46:45 GMT

Hi @onayohob23

Please correct loads and support parameters

Re: Analysing and detailing capping beam on piles

onayohob23 — Tue, 26 Sep 2023 12:41:42 GMT

Thanks for this, I suppose now I need to flip the beam dimensions (depth/breath) to suit this new orientation.

Is there generally a better way to analyse capping beams in Robot? i.e. If I wanted to analyse all 4 sides of capping beam in a rectangular basement, and there are steps and levels changes in some locations, is there a specific way to go about this?

Re: Analysing and detailing capping beam on piles

onayohob23 — Tue, 26 Sep 2023 13:00:49 GMT

I'm still getting the same error unfortunately.

Re: Analysing and detailing capping beam on piles

Simau — Tue, 26 Sep 2023 15:46:44 GMT

Try giving some dimesions

to supports

Re: Analysing and detailing capping beam on piles

onayohob23 — Tue, 26 Sep 2023 16:01:25 GMT

I don't see what this has to do with anything? Am I missing something?

Anyway, I did it and still get an error.

Re: Analysing and detailing capping beam on piles

Simau — Wed, 27 Sep 2023 12:31:09 GMT

@onayohob23

First apply the parameters to the beams

Re: Analysing and detailing capping beam on piles

onayohob23 — Thu, 28 Sep 2023 09:25:45 GMT

Thanks. This worked. So it seems we need to be very careful of the orientation that we're modelling.

I'm not too happy with having to define one type of bar diameter in Calculation Parameters. Ideally the program should choose the correct bar size/no. of bars, so we don't see something obscene like 30 No. H16 bars!

@Simau I'm keen to know if you were to model this from scratch, using the attached background, how would you start to go about it (i.e. axis definition etc)?

Re: Analysing and detailing capping beam on piles

Simau — Thu, 28 Sep 2023 10:11:12 GMT

@onayohob23

You must create a new calculation parameter other than standard. Take a look at this webinar
https://www.youtube.com/watch?v=-vfm3FIr1kU&list=PLY-ggSrSwbZqow_60fiqJwS69mg1nQMzk&index=20&ab_channel=AutodeskBuildingSolutions