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You can find the question and the answer in this link!

https://precast.org/2018/11/questions-from-the-field-12/

Yes, I think Reinforcing steel can be welded instead of using steel wires ties

Dear Segun Michael Abegunde .... thanks for joining our discussion...

Dear M. A. A. Al- Fatlawi .... thanks for joining our discussion...

Dear Hamid Reza Samadifard .. .... thanks for joining our discussion...

Dear Ahmed S. H. Suwaed ... thanks for answering..

Need you point of view based on your experience... its a technical question, where might find different answer ... came similar or different from what had been listed in the site where my question came from....

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Its had been long time from 2005... I'm so glad to find your answer her...

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However, it’s important to differentiate tack welds from structural welds. Structural welds occur when the weld is expected to transfer design loads from one bar element to another. Another example requiring a structural weld could be attaching an embedded steel item, like a lifting hook or weld plate, to the internal reinforcement as part of the structural function of the product. Those scenarios require welding practices that follow the AWS Structural Welding Code D1.4, which also addresses the weldability of different types of steel rebar (ASTM A615 vs. ASTM A706, for example).

( REF. : https:// precast. org /2018/11/questions-from-the-field-12/)

Dear Shaban A. A. Abdel-Raheem... thanks for your comment

It depends on local standards and codes. Much steel is welded in to grid patterns for light weight constructions like wire and light bars. Heavier steel like rebar is usually tied which allows some movement with temperature changes.

Welding heavier parts is possible, but must be made more secure than a tack weld if the parts are quiet heavy and will be put through daily temperature cycles before the concrete is poured.. Also corrosion resistance is important and sometimes compromised by welding. A zinc compound is available but not as good as galvanizing or other hot passivation.

As wire ties or plastic-type clips are used to fix steel bars in their place during the cast of concrete; thus any alternate method that satisfy this function may be adopted.but one should but in mind the effect of temp.of welding in steel properties and the cost. sometimes, the spiral of piles are welded to the longitudinal reinforcement. Several YouTube videos can be seen with "

Cage Welding Machine "

Unqualified comment: Environment and Objective matters. For an open structure well modeled given standards, it could be stressed/energized in any manner, given the model parameters (definitions) are not altered, to attain dissipation and allowable yield.

For concrete, environment and scale is important. Little temperature variation at small segmented scale welds can be used witout altering the "model" given objectives.

For a bigger scale and greater temprature variations both "concurrent" and "relative" displacment and yields be taken into account.

One should know how possibilities of loads/stresses given materials used are created and dissipated for a chosen design/function/objective.

Yes it can. The codes (all codes) are not too loud about it anyway. But the bond in concrete and the transfer stress between cut bar lengths must however not be jeopardized. I have done this several times on various sites. The slag must be completely removed and the tack weld thickness, length, spacing and fusion of the bars must be adequate. The Codes are silent because it may not be adequately and appropriately carried out, since there is the possibility of the development of micro-cracks between the weld and bars and reduction in cross sectional area of the bars at the tack points when the fusing temperature is in appropriate. Come to think of it; what type of strengthening does the binding wires and plastics provide in the bars. The essence of the bar lap length is to ensure continuity and adequate transfer of stresses in the bars and concrete through bonding. This simply depends on length of lap and closeness of the bars.Please check my papers online on the optimization of lap lengths for reinforcements in concrete (steel and CFRP differently).

Dear Ayad Abdulhameed Sulaibi ... Thanks for answering..

Dear Jerry Decker ... Thanks for your very good answer...

Let me ask you.. on the same subject... you know, there are two main type of welding.. Site welding and Factory welding... for me, I will accept factory welding on site welding... what did you think..?

Dear Qasim Alabbasi ... Thanks for answering..

Dear Bilal Hassan .. thanks for answering..

Dear O.s. Abejide ... Thanks for your answering..

Dear O.s. Abejide ... Thanks for your answering..

The possibility of welding reinforcing bars is admitted by the Eurocode. In my experience of a tunnelling project built by TBM, there was an on-site precast concrete factory to prepare the tunnel lining segments to be applied by the TBM. The factory included a carousel for steam curing and an automated cutting-bending machine, while steel fixing of the reinforcement cages was by tack welding. The welding was carried out with MIG arc welding machines, without electrodes, using continuous welding with wire under an inert gas flow. The welded steel bars were regularly tested in external laboratories. Additionally the quality control team was visually checking for indented steel bars. The results demonstrated that there is no loss of strength in points that are properly welded, and In conclusion, tack welding can be and commonly is succesfully used.

yes you can . practically, I do it more times, specially with column dowels and and splices .

yes you can . practically, I do it more times, specially with column dowels and splices .

Dear Eugenio Zoppis ... thanks so much for your excellent answer..

Dear Abdul Kareem M. B. Al-Shammaa ... Thanks for answering..

Dear Eugenio Zoppis... I did ask that for Jerry Decker .. about the factory control welding.. where its might done mechanically.. but, .. did you recommend site welding... where its done by labors ... even these labors are professional...?

While welding on site in generally not recommended, it all depends on creating appropriate working conditions and a robust quality control system where the work is carried out. As in the instance I mentioned, factory type conditions were created on Site in a remote area of Africa, where I had no space constraints. Quality control can be established anywhere and besides, the testing of samples can be carried out off-site.

Generally, the advantage of welding on site is the concrete lift preparation speed, while prefabricating steel cages off-site (welding makes a solid cage) has the disadvantage of higher transport costs from factory to site. In a large construction site, the establishing an on-site welding yard where cages are prefabricated under controlled quality conditions, gives the best of both options. Last point: the parameter to check on quality certificates from steel supplies is the carbon content. You may find further guidance on welding reinforcing steel at the following link: https://www.ukcares.com/downloads/guides/PART6.pdf

Dear Eugenio Zoppis ... Thanks for answering.. and for the reference,...

Its really all related to " controlled quality conditions " and how can we achieved the required quality to keep the required strength of steel that may lost during welding process....