splicing in long span slabs

[ticas]

Do you have sites where all of this are shown in details? Two long span slab 5 meters length are to have continuous bars running at bottom and top. I pressume the splicing of those bars is similar to splicing in beam where the top continuous bar are spliced at center, but can you splice the lower bars right at beam support instead of near it the beams?

 

[rowingengineer]

Do you need to splice if possible I would source 10m long bar?

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[ticas]

Oh, the 5 meter is the short span length, the long span length is 7 meters. I wonder if the splice can be done right at the beam or it has to be l/4 near the beam. Why can't it be spliced right at the beam?

 

[dik]

12m and 18m bar total rolled lengths are common in these areas...

Dik

 

[BAretired]

The bottom bars can be spliced at the beam, in fact that is the best place to splice them if they need to be spliced at all.

BA

 

[ticas]

what developement length do you use in the beam?

 

[hokie66]

The length of any splice depends on the reason for the splice. In many cases, slab bottom bars are not spliced at supporting beams, but rather are only extended a nominal distance beyond the face of the support in accordance with a code provision. If bottom bars are spliced at supports, the design engineer has a reason. This could be for general robustness or vertical seismic forces. The responsible design engineer should make the decisions as to required splice length.

 

[dik]

Attached sketch is a common way to reinforce...

Dik

 

[hokie66]

Dik,
Maybe your sketch didn't come through as intended, but it doesn't give any useful information. Slab on ground?

 

[dik]

Suspended slab with 5m and 7m spans.

The centrelines are the supports, the solid bars are the top bars and the dashed bar is the bottom bar.

The bottom bar is continuous, the top rfg that extends past the interior support is lapped with a similar bar from the other side. and dowels are placed in the top for the balance of the top rfg at the end supports.

Dik

 

[hokie66]

I think that was understood, my comment was just about your draftsmanship. What appears on my screen looks like a slab on grade on a granular layer, with central reinforcement and some bars above the slab.

 

[rowingengineer]

and people are suggesting that engineers should be able to draft and design. I'm going to stick to designing.

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[dik]

Sorry Hokie... I drew the rebar above the slab. The lengths of the hooks is greater than the slab thickness and they would have to be shortened by rotation.

Dik

 

[BAretired]

Why would you bother hooking the top bars if you are going to use hooked dowels? And since we don't know much about ticas' structure, we don't know how long the vertical leg of the dowels would be. I suggest that we use straight top bars and develop the 'L' shaped dowels as required.

BA

 

[hokie66]

You guys must have a different definition of "dowel" than I do. If poor old ticas wasn't confused before, I am sure he now is.

 

[dik]

The long hooked bars provide part of the reinforcing and the short hooked bars provide the balance.

Sometimes with heavy industrial stuff, it is possible to get the -ve moment into mid-span due to moving equipment across a relatively unloaded slab.

Hokie... in these environs, it's not uncommon to have the 'short hooked bars' referred to as dowels, for example provide 15M@300T Dwls, All Around. Nobody seems to have a problem with it!

Dik