splice length of the baem and slab for about 17.5m and 15.35m Spans

[syedyh58]

Dear All
Good Afternoon to every body,

I have span around 17.35x15.415m of waffle slab with the periphery beam and the rib beams inside ,the slab thickness is 100mm,periphery beam size is 350x800mm and ribs beam inside at every 1.0m size is 250x800mm (see attached for your reference ).

As per standard the slab and beam bars,the top bars shall be lapped at mid span and bottom bar lapped at support.in connection to above I have the span 17.35m and 15.35m for all rib beams in longitudinal and transverse direction for this where I can provide splice lapped for about span 17.35m.and 15.35m. since the standard length of the bar available in market are only 12.0m. can you please provide the information where I should provide the splice lapped for top and bottom bars for beam and slab.
and there was no main beam crossing the mid span.

regards
syed

 

[KootK]

Usually, top steel is not detailed to be continuous so spicing it isn't an issue. You could centre your 12m bottom bars within your spans and splice at the bar ends if desired. The idea is just to keep the splices out of the highest moment regions.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[TXStructural]

You can splice bars any place outside of regions of maximum stress in the bars. This means that both top and bottom bars in the ribs can usually be spliced at 1/3 to 1/4 span locations. Laps should be Class B (full tension laps) and laps should probably be staggered since there will be demand on the bars. Your models or calcs should point to reasonable locations for the splices.