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Expansion joint

Expansion joint

Expansion joint

hi all,

how long u think should be between Exapnsion joints in R.C Structures ? i have a building that is 50m long, do i have to make an Expasion joint for it ?? if yes, can i just increase the stresses instead of making Expansion joint ?


RE: Expansion joint

Expansion joints should be located at intervals of 30 meters.  Vertical expansion joints are incorporated into the wall to account for expansion due to temperature changes. These joints may be filled with flexible joint fillers. Greased steel dowels are often cast horizontally into the wall to tie adjacent sections together. We often use them for work stops to move the formwork and separate construction pours (delay in next pouring).  Also, most joints in beams and slabs are formed with a key, or cast-in sacrificial stop-ends that provide shear transfer in addition to rebar.  

Vertical expansion joints also help foundation settlements over long distances.


RE: Expansion joint

Refer to Prestressed Concrete Institutes publication "PCI Design Handbook" which has a chart on maximum recommended expansion joint lengths for concrete buildings. The chart considers whether the building is heated or not, air conditioned, fixed column bases, and lateral stiffness for joint distance adjustments.  The chart is derived from National Research Council Technical Report No. 65.  

You can consider additional stresses in the concrete but most likely more cracking will occur as the joint distance is increased.  Also wall finishes  both exterior and interior may become distressed as the joint lengths increase.

RE: Expansion joint

Mr. frad, u didnt say the maximum length i can go without Expansion joint, also increasing the load 10%,20% or what ??

i know my question was not spicefic, so to make it clear its a Villa 3 floors hight and about 50m X 10m, i and its in Egypt, cairo.

in that chart u r talking about, whats the maximum Length in my condition, consider the worest case or near the worest.

** Mr boo1, thx for replying, but i asked some fellows here and some say 40m, others say 100m !!i dont know about the 30m !!! i'm very confused now !!

Thx for concern to all,


RE: Expansion joint

I also remember the 30m rule from earlier in my career.  I'm sure that, if you account for the increased stresses, you can avoid the expansion joint.  However, the price for being allowed to do that is that you accept a higher risk of cracking, and you rely even more than usual on the quality of workmanship on site.

mfrad's posting refers to other possible consequences.  I suggest you refer to the documents which mfrad kindly listed for you.

Good luck.

RE: Expansion joint

Expansion joints are designed for seismic, temp, wind and other external forces encountered.

RE: Expansion joint

hmmmmm, dear ayfarm, i know that im asking about the length i can go safe without doing Expansion joint.


RE: Expansion joint

Utilizing the 30M as A guideline. I would recommend spliting the wall with the EJ at the center @ 25M.

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