Difference between One Way Slab and Two Way Slab

Looking for the difference between one way slab and two way slab? Then here your doubts about this topics will be cleared.

I have explained the one way and two way slabs first then their differences so that you can easily understand the topic.

Let’s get started.


At the point when a substantial slab is upheld on every one of the four sides and the proportion of long range to limited capacity to focus more prominent or equivalent or than two, this implies it’s a one-way slab. The heap on the one-way slab is conveyed by the limited capacity to focus one course. Anyway the principle support bar and dispersion bar a cross over way.

The equation of One-Way Slab: Longer range (Ly)/shorter range (LX) ≥ 2


The heading (more limited side of one-way slab) in which burden is moved is known as length. It’s is intended for the crossing bearing without anyone else as it twists just a single way.

The primary strain supporting bars, subsequently, run equal (dispersed consistently) to the more limited range and are normally positioned at the lower part of the slab.

Difference between One Way Slab and Two Way Slab

The more extended way, a base measure of support is given to deal with the shrinkage and temperature and impacts toward that path. This support steel is known as the circulation steel or auxiliary support.

This steel likewise helps in disseminating the heap. The circulation of steel helps in dispersing the heap dynamically over a bigger width, in this manner balancing the neighborhood impact like plastic shrinkage breaks because of temperature and shrinkage. In any event, when a slab is upheld on every one of the four sides, the conduct of slab is required to be as a one-way slab just as apparent from the diversion form

Least Depth

Least profundity of the one-way substantial slab, the majority of the occasions is represented by redirection measures. Now and then the base profundity is satisfactory according to flexure plan, however on the off chance that avoidance measures aren’t satisfied such slabs will confront vibration much under little loads like strolling, bouncing, and so on Albeit in any event, checking the plan consistently may give you less profundity, always check for avoidance. Here you can give possibly bigger profundity and can decrease steel to streamline on the general expense. Kindly note that the vibrations never give a sensation of the protected structure to inhabitants.

Types of One way Slabs

One-way Solid Slab with beams

This sort of slab is upheld on radiates. Contingent upon shaft and section plans, this framework can be intended for wide scopes of the heap conditions.

One-way Ribbed Slab with beams

One-way Ribbed Slab with radiates is utilized for the places of business (low ascent), stopping designs, and stockrooms.

One-way Ribbed Slab with integral beams

The one-way ribbed substantial slab is given a more noteworthy range when contrasted with the substantial strong slab. The one-way ribbed substantial slab is conservative when it’s utilized in the secluded or pre-assembled structure.

One-way Slab with the Hollow Block

One-way substantial slab activity is expected in a ribbed slab with joist radiates made of the precast twofold tee area, in the ribbed floor with fundamental pillars, and additionally in empty square or empty cored slabs.


  • In viable, One-way is upheld by just two equal pillars or dividers.
  • Main reinforcement (rft) is given in one bearing to one-way slabs.
  • one way slab has primary strength the most brief way
  • Deflected state of the one-way slab is tube shaped.
  • One way substantial slab twists or avoids toward a path opposite to the supporting edges
  • Slab board is upheld the short way of one-way slab on two inverse sides
  • The thickness of the one-way slab changes between 100mm to 150mm dependent on the avoidance thought and range


The Two Way Slab is for the most part upheld on all sides of dividers or radiates and while moving the heaps to the dividers or pillars it curves or twists in the two ways.

The slab is known as two way slab when the proportion of the long range is under 2 and in-floor of multi-story structures this kind of slabs are for the most part utilized.

Under the activity of burdens, the two way slab will avoid in a dish or saucer-like structure and if the slab isn’t projected solidly with the backings like dividers or pillars, corners of the two-way slab lift up.

Also read: One Way Slab Advantages and Disadvantages (Explained)

The principle bars are given in the two ways and they are opposite to one another in two-way slab and relying on length, the standard thickness of these slabs is in the scope of 100mm to 200mm. For the board evaluates to 6m x 6m two-way slab is reasonable and prudent.

Two Way Slab Design Methods:

There are two strategies for two-way slab plan as given beneath;

  1. Direct Design Method
  2. Coefficient Method


Direct Design Method for two way slab decides or recommends minutes for various pieces of the slab board without the need to lead primary investigation.

The Procedure of Two Way Slab Design by Direct Design Method:

There are the accompanying strides in this strategy, for example,

  1. Determine slab format and type and for staying away from extreme diversions and fulfill shear at the inside and outside segments, pick slab thickness that ought to be sufficient.
  2. Then pick the immediate plan strategy and in the slab ascertain positive and negative minutes.
  3. Across slab width, convey minutes and on the off chance that shafts are available, indicate a part of minutes to the pillars.
  4. For minutes that found in two past focuses, figure fortifications and check shear strength.
Limits of Direct Design Method:

There are the accompanying limits of direct plan strategy, for example,

  1. In every bearing, there should be in any event three constant ranges and the inside bad minutes will in general be excessively little if there are less boards.
  2. The proportion of longer and more limited ranges inside the board should not surpass 2 and boards ought to be rectangular.
  3. Successive range lengths should not vary by more than 33% of the biggest range length toward every path.
  4. For slab that exposed to gravity load just, this technique is relevant.


In the American Concrete Institute in 1963 to plan two-way slabs conveyed by steel radiates, profound shaft, or dividers this technique was given.

This strategy utilizes tables of second coefficients for various slab edge conditions and these conditions depend on the versatile examination.

The slab is separated into the centre strip and segment strip toward every path as per the coefficient approach and the width of the last is equivalent to the one-fourth of the board width.

Support Requirements:

During support specifying, the accompanying thought given by ACI Code will be considered;

Arrangement Sequence:

To the top and lower part of the slab, support bars for limited capacities to focus prescribed to be put nearer and in limited abilities to focus, will have more noteworthy viable profundity.

It should be plainly noted and displayed in the drawing if uncommon support situation is thought of and this arrangement design ought to be kept up.

Substantial Cover:

To the outside of support in slabs least, the reasonable cover is 20mm separated from the condition where the slab is in direct contact with the earth to climate and this is as indicated by the American Concrete Institute ACI code.

Dispersing Requirements:

For positive and negative minutes in both the centre and segment strips, the most extreme dividing of support at basic plan segments will not surpass multiple times the slab thickness. At any area, the bar dispersing will not surpass 450 mm.

  1. According to systems gave decide the thickness of the slab and decide the calculated burdens.
  2. By utilizing tables, decide second coefficients.
  3. In every heading, register positive and negative minutes.
  4. Then in the last advance compute the support region and then the quantity of bars and their dispersing.

Kinds of Two Way Slab:

There are the accompanying kinds of this slab, for example,

  1. Two Way Flat Plates Slab
  2. Two Way Flat Slabs
  3. Two Way Waffle Plate Slab
  4. Two Way Slab With Hollow Block

Difference between One Way Slab and Two Way Slab

  1. The one way slab is upheld by a bar on two inverse side in particular while the two way slab is upheld by the shaft on every one of the four sides.
  2. In one way slab, the heap is conveyed one way opposite to the supporting bar. While In two way slab, the heap is conveyed in the two ways.
  3. One way slab two inverse side help pillar/divider while Two Way Slab four side mins all side upheld bar/divider.
  4. One way slab is twist just in one crossing side course while load move.
  5. One way slab is twist just in one crossing side heading while load move.
  6. If L/b the proportion is more prominent than or equivalent 2 or then it’s anything but a one-way slab while Two way slab is twist both spreading over side course while load move.
  7. In one-way slab, the heap is conveyed one way opposite to the supporting pillar while in two-way slab, the wrench is given in four ways.
  8. The redirected state of the one-way slab is tube shaped while if L/b the proportion is under 2 then it’s anything but a two-way slab.
  9. Chajja and Varandha are pragmatic instances of one-way slab while in two-way slab, the heap is conveyed in the two ways.
  10. In one-way slab amount of steel is less whereas the redirected state of the two-way slab is a dish or saucer-like shape.
  11. Main Reinforcement is in give limited ability to focus to banding whereas two-way slabs are utilized in helpful floors of the Multi-storey structure.
  12. Ly/Lx ≥ 2 one way slab traversing while Ly/Lx < 2 two way slab spreading over.
  13. One way slab close about 100mm to 150mm dependent on the diversion. In two-way slab amount of steel is more when contrasted with the one-way slab. Fundamental Reinforcement is in give limited capacity to focus to banding. One way slab prudent close about 3.5 m.
  14. Two way slabs is in the scope of 100mm to 200mm contingent on. Two way slab may affordable for the board sizes close about 6m x 6m.
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