One Way Slab
One way slab is supported on two opposite side only thus structural action is only at one direction. Total load is carried in the direction perpendicular to the supporting beam. If a slab is supported on all the four sides but the ratio of longer span (l) to shorten span (b) is greater than 2, then the slab will be considered as one way slab. Because due to the huge difference in lengths, load is not transferred to the shorter beams. Main reinforcement is provided in only one direction for one way slabs.

Two Way Slab
Two way slabs are the slabs that are supported on four sides and the ratio of longer span (l) to shorter span (b) is less than 2. In two way slabs, load will be carried in both the directions. So, main reinforcement is provided in both direction for two way slabs.

Difference Between One Way Slab and Two Way Slab
There are some basic differences between one way slabs and two way slabs. To clear the concept of one way and two way slabs a table is shown below.
One Way Slab |
Two Way Slab |
One way slab is supported by beams in only 2 sides. | Two way slab is supported by beams in all four sides. |
The ratio of longer span panel (L) to shorter span panel (B) is equal or greater than 2. Thus, L/B >= 2 | The ratio of longer span panel (L) to shorter span panel (B) is less than 2. Thus, L/B < 2. |
Main reinforcement is provided in only one direction for one way slabs. | Main reinforcement is provided in both the direction for two way slabs. |
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Badmus azeezat adedoyin says
Am very glad 2 find ans 2 my questn more grease 2 ur elbow
Asekeen says
Thanks for the inspiration. 🙂
Mansoor says
15′ lenth 19′ width slab..give me the how many dia bars i have to provide…along shorter and longar direction..and in which side i have to give the crank…
Anwar Shefa says
Thank you for a good cooperation in civil engineering study.
Egbedokun Taiwo says
I love this post. And it has realy provided answers to few questions on my mind. Thanks
rahul mehta says
hey, you doing a great work for civil engineering students like me. all lights and claps to the admin asekeen 🙂 this forum helps me a lot.
hammed ola says
I am very grateful for answering my questions on one way slabs and two way slabs.
mark says
You are wonderful guy and great initiative for civil engineers. Nice explanation on one way slab and two way slab difference.
ramachandran says
50 foot length and 21 foot width what type slab
Shajnin says
One way slab.
AASHIF KHAN says
one way
rahul kumar says
good and satisfactory answer which gives clear concept.
nick says
9.6m width 6.5 length?
shahe says
Two way slab as width/length < 2
abdi cadiim says
mashaallah this page is usefull for all engineers. I hope to get alot of theory.
asish panigrahi says
This data is good for know the difference between one way slab and two way slab but if u provide to how to reinforcement design in one way and two way slab so its very helpfull
AASHIF KHAN says
how the system of provide the r/f of slab
Ashutosh says
Thanks for the post … it helped me a lot
kamran says
Sir
pleas tell me in detail in one salb and two way slab,,,,i im waiting for yours good response,,,,,,
aRUN says
how will u find it after moulding???
SHAHID SAQI says
thanks alot. it help me alot to become a civil engineer
Hitesh Patel says
given clearification is very excellent
David says
Thank you! I’m very happy that I was able to clarify my doubts.
Gyanendra mishra says
I liked this chapter.and I want more about r.c.c.