contiuity of additional rebars

[Hamza Abu-Jajeh]

Hi All,
i am wondering that dose additional rebars required continuity ?
assuming that an additional bars required for a length more than the available length at site then dose the overlapping required or it can be placed without overlap, i have a similar case that at constriction joint location the couplers of additional reinforcement are missing so no continuity for the additional will be available, meanwhile the main mesh couplers are existing and no issues in this regards.

 

[r13]

Additional reinforcing is required for a purpose, the continuity need to be maintained (thru splice/coupler) until it is no longer required.

 

[Hamza Abu-Jajeh]

Thanks for your response, but in case the couplers are missing what we can do other than drilling with chemical as it will be nightmare

 

[JLNJ]

Bars must be appropriately lapped, anchored, coupled, developed, etc.

Order longer bars and have them delivered to the site. (Welding might be possible in rare cases.) The situation is likely full of complications. There may be no simple answer. Go ask the engineer responsible for the design what needs to be done.

 

[r13]

We need more information from you. Does the concrete poured or not, or else (only one side poured on the CJ)? What exactly the function of the additional bars? Where the bars are located, in slab, wall..?

 

[Hamza Abu-Jajeh]

the concrete has been poured at one side of the CJ, this CJ is in a tower raft.
the additional rebars are provided to cover thermal effects and differential settlement between the two parts.

so its not about ordering new rebars longer but to do the drilling at bottom side of raft 650 mm depth after placing all top rebars is like nightmare.

i am trying to do some shipping for the concrete at that location and place the rebars with welding which i don't believe that its the suitable solution.

 

[rowingengineer]

Any chance of a sketch

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."

 

[r13]

If the rebar is weldable grade, then weld. Otherwise, drill and grout.

 

[Agent666]

You could also investigate mechanical splices, depending on access and loads these might be an option.

There are several types out there in the market, from one's that have screws that hold the bar in place to one's that are mechanically pressed onto the bars. Some are designed to only be capable of yielding the reinforcement, but often this may be sufficient depending on location, loads, etc.

 

[r13]

Agent666,

The steel erector forgot the mechanical couplers at the first place But the "mechanically pressed onto" type is quite interesting. Can you elaborate more?

 

[BridgeSmith]

But the "mechanically pressed onto" type is quite interesting. Can you elaborate more?

A web search for "wedge-type reinforcing couplers" produces pictures that should explain it pretty well.


Rod Smith, P.E., The artist formerly known as HotRod10

 

[r13]

Rod,

Thanks. I've seen it before, but never used. But a good fit for the problem here, than drill and grout.

 

[BridgeSmith]

Sorry, retired13. I misunderstood your query.

Yes, the wedge-type where the bars bypass requires less exposed length than the screw type. I think both types are available in configurations that develop the yield strength of the bars. The wedge-type ones are generally more popular where there are a large number of bars to be spliced, because they're cheaper and faster if you have the press for them.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[Agent666]

Example of a press fit type, similar types available all over the world.

http://www.hardman-de.com/

 

[Hamza Abu-Jajeh]

thanks all for the inputs, the issue has been resolved.
the information i got earlier from the site wasn't describing the full image, after i visited the site i have found that additional rebars were provided but in higher level.
after that i have checked the moment diagram for that section were luckily it been found as negative moment at that location.

so based on the above i agreed with engineer for the details as below