Waffle slab Applications of waffle slab Materials Spans considerations Purpose Advantages & Disadvantages of waffle slab Types of construction Construction techniques Types of supports provided Construction details Casting time of the slab Design of waffle slab reinforcement details Types of grid slab Waffle pods providers in india Types of pods

1. INTRODUCTION TO WAFFLE SLAB

2. ➢ WAFFLE SLAB OR RIBBED SLAB IS STRUCTURAL COMPONENT
WHICH IS PLAIN ON ITS TOP AND CONTAINS GRID LIKE SYSTEM
ON ITS BOTTOM SURFACE.
➢ THE TOP OF RIBBED SLAB IS NORMALLY THIN AND THE BOTTOM
GRID LINES ARE GENERALLY RIBS WHICH ARE LAID
PERPENDICULR TO EACH OTHER WITH EQUAL DEPTH.
➢ WAFFLE SLAB HAS TWO DIRECTIONAL REINFORCEMENT.
PLAINTOP
GRID SPACE/FORM SPACE
RIB COLUMN
INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
INTRODUCTION

3. INTRODUCTION
TO
WAFFLE
SLAB
➢ THE TOP OF THE WAFFLE SLAB IS GENERALLY SMOOTH, LIKE A
TRADITIONL BUILDING SURFACE,BUT THE UNDERSIDE HAS A SHAPE
REMINISCENT OF A WAFFLE.
➢ STRAIGHT LINES RUN THE ENTIRE WIDTH AND LENGTH OF THE
SLAB,GENERALLY RAISED SEVERAL INCHES FROM THE SURFACE.
➢ THESE RIDGES FORM THE NAMESAKE SQUARE POCKETS OF THE ENTIRE
LENGTH AND WIDTH OF THE SLAB.
IMPACT
SCHOOL
OF
ARCHITECTURE
STRAIGHT LINES
RUNNING ALONG TO
HORIZONTALLY ANS
VERTICALLY
SQUARE POCKETS

4. ➢ WAFFLE SLAB CAN BE USED BOTH AS A CEILING AND FLOOR SLAB.
➢ THEY ARE USED IN THE AREAS WHERE LESS NUMBER OF COLUMNS ARE
PROVIDED,GENERALLY WHERE THE SPANS ARE HUGE.
➢ OFTEN USED IN INDUSTRIAL AND COMMERCIAL BUILDINGS
➢ SOME EXAMPLES COULD BE - AIRPORTS,GARAGES,BRIDGES,AUDITORIUM AND OTHER
STRUCTURES.
➢ IT HAS GOOD VIBRATION CONTROL CAPACITY BECAUSE OF THE TWO DIRECTIONAL
REINFORCEMENT. SO,IT IS USEFUL FOR PUBLIC BUILDINGS TO CONTROL VIBRATIONS
CREATED BY MOVEMENT OF CROWD.
INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE

5. ➢ CONCRETE
INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ STEEL ➢ WOOD
WAFFLE SLAB CAN BE CONSTRUCTED BY THREE
MATERIALS, THAT IS
CONCRETE,WOOD AND STEEL.

6. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ A WAFFLE SLAB WITH A 40+5 CM EDGE MAY REACH SPANS OF 11 (+-1M) FOR SERVICE OVERLOADS BETWEEN 3 AND 4 kN/m2 ,
➢ THIS BEING BROUGHT BACK TO 8 M IF THE SERVICES OVERLOAD INCREASE TO 10 kN/m2 .(A COMMERCIAL SURFACE IS
USUALLY ASSIGNED A SERVICE OVERLOAD OF 5kN/m2 AND CONCENTRATED LOADS OF 7 kN).
➢ FOR SERVICE OVERLOADS THAT DO NOT EXCEED 5 kN/m2 RANGE FROM 5 TO 12 M.
DOME DEPTH
20-51 CM
SPAN/24
DOMES 48-76 CM

7. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ THE WAFFLE SLABS PROVIDES STIFFER AND LIGHTER SLABS THAN AN EQUIVALENT FLAT SLABS.
➢ THEY PROVIDE LOW FLOORING DEFLECTION, HAVE FINISH AND FIRMNESS.
➢ WONDERFUL VIBRATION CONTROL.
13 CM 48 CM 13 CM
7 CM 54 CM 7 CM
4 CM
21 CM

8. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ LOAD BEARING THE CAPACITY OF WAFFLE SLAB IS HIGHER THAN OTHER TYPES OF THE SLAB.
➢ WAFFLE SLABS HAVE GOOD STRUCTURAL STABILITY.
➢ THE CONSTRUCTION OF A WAFFLE SLAB IS VERY SPEEDY AND FAST.
➢ WAFFLE SLAB CAN BE USED FOR LARGER SPAN WITH LESS NUMBER OF COLUMNS.
➢ WAFFLE SLAB CAN BEAR A LARGER AMOUNT OF LOAD AS COMPARED TO THE CONVENTIONAL SLABS.
➢ WAFFLE SLABS ARE LIGHTWEIGHT AS COMPARED TO OTHER TYPES OF SLABS BECAUSE OF THE LESS DEAD LOAD OF
THE SLAB.
➢ WAFFLE SLAB HAS HIGH VIBRATION CONTROL CAPACITY.
➢ WAFFLE SLABS ARE ATTRACTIVE AND HAVE GOOD AESTHETICAL APPEARANCE WHEN EXPOSED.
➢ ALL THE SERVICES LIKE LIGHTING, PLUMBING, ELECTRICAL AND AIR CONDITIONING ARE EASILY PROVIDED IN THE
WAFFLE SLAB WITHOUT ANY DIFFICULTY.

9. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ THE FORMWORK WHICH IS REQUIRED FOR THE CONSTRUCTION OF THE WAFFLE SLAB IS VERY COSTLY.
➢ THE CONSTRUCTION OF THE WAFFLE SLAB REQUIRED SKILLED WORKMANSHIP.
➢ WAFFLE SLAB CONSTRUCTION CANNOT SUITABLE TO BEAR HIGH WIND LOADS.
➢ THE FLOOR HEIGHT IN THE WAFFLE SLAB IS HIGH AS COMPARED TO THE CONVENTIONAL SLAB DUE TO WHICH
THE NUMBER OF FLOORS IN THE STRUCTURES IS GET REDUCED.
➢ THE WAFFLE SLABS CANNOT BE CONSTRUCTED ON THE SLOPE AREAS.
➢ THE MAINTENANCE OF WAFFLE SLABS IS EXPENSIVE AND DIFFICULT.

10. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ THE CONSTRUCTION OF THE WAFFLE SLAB IS DONE IN THREE WAYS. FIRST IS THE IN SITU CONSTRUCTION OF THE
WAFFLE SLAB, PRECAST CONSTRUCTION AND THE PREFABRICATED CONSTRUCTION.
➢ IN SITU CONSTRUCTION OF WAFFLE, THE SLAB IS DONE BY CASTING THE WAFFLE SLAB ON-SITE AS PER THE
DESIGN AND THE SIZE REQUIRED.
➢ IN THE PRECAST CONSTRUCTION OF WAFFLE SLAB, THE SLAB PANELS ARE CAST AT ANOTHER PLACE AND JOINED
TOGETHER WITH THE REINFORCEMENT.
➢ IN THE PREFABRICATED CONSTRUCTION OF WAFFLE SLAB, THE REINFORCEMENT IS PROVIDED IN THE SLAB
PANELS WHILE CASTING.

11. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ THE CONSTRUCTION COST OF THE
PREFABRICATED SLAB IS HIGHER
AS COMPARED TO THE OTHER TWO
SLABS.
➢ CONSTRUCTION OF THE WAFFLE
SLAB IS GENERALLY PREFERRED
FOR SPANS LONGER THAN 12 M.
➢ WAFFLE SLAB CONSTRUCTION
REQUIRED ABOUT 30% LESS
CONCRETE AND 20% LESS
REINFORCEMENT.

12. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
WAFFLE SLAB WITH
SOLID HEAD
WAFFLE SLAB WITH
BAND BEAM
VIEW
PLAN
1 2

13. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ THE CONSTRUCTION OF A WAFFLE SLAB IS GENERALLY SUITABLE FOR FLAT AREAS.
➢ THE VOLUME OF CONCRETE WHICH IS USED IN THE WAFFLE SLAB IS LESS AS COMPARED TO OTHER TYPES OF SLABS.
➢ WAFFLE SLABS HAVE GOOD SHRINKAGE RESISTANCE.
➢ WAFFLE SLAB REQUIRED VERY LESS AMOUNT OF STEEL AND CONCRETE AS COMPARED TO OTHER TYPES OF SLABS.

14. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ WAFFLE SLABS ARE THE STRUCTURAL COMPONENT
WHICH IS PLAIN FROM THE TOP AND HAS A GRID-LIKE
PATTERN AT THE BOTTOM SIDE.
➢ WAFFLE SLABS CAN BE USED FOR BOTH
CONSTRUCTIONS OF THE FLOOR SLAB AS WELL AS
CEILING SLABS.
➢ A FLAT SLAB CANNOT BE CONSTRUCTED FOR A LONGER
SPAN AND ALSO GET CRACKED.
➢ WAFFLE SLABS ARE THE SPECIAL TYPE OF SLAB WHICH
IS MAINLY CONSTRUCTED FOR THE LONGER SPAN AND
HAS A CRACK AND SAGGING RESISTANCE.

15. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ CONSTRUCTION TIME: A FULLY PRECAST WAFFLE SLAB ONSITE IS ONLY LEFT WITH HOISTING OPERATIONS AND IT
BCAN BE EXECUTED ON MULTIPLE FLOORS SIMULTANEOUSLY ; THIS PROVIDES THE FASTEST CONSTRUCTION SPEED
OF 1.5 SPAN/DAY
➢ FOR SEMI PRECAST WAFFLE SLAB,SINCE CONCRETE POURING AND CURING ARE STILL REQUIRED ONSITE, THE
CONSTRUCTION SPEED CAN ONLY ACHIEVE 1 SPAN/DAY.
➢ FOR TRADITIONAL CONSTRUCTION,SINCE ALL OPERATIONS IS CARRIED OUT ONSITE, THE CONSTRUCTION SPEED IS
SLOWEST AT ONLY 0.5 SPAN/DAY.
➢ THEREFORE,THE PRECAST TECHNIQUE DOES PROVIDE A SIGNIFICANT EFFECT ON THE COMPRESSION OF
CONSTRUCTION TIME.

16. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ THE DESIGN OF THE WAFFLE SLAB DEPENDS UPON THE TOTAL AREA ON WHICH THE WAFFLE SLAB IS REQUIRED.
➢ THE THICKNESS OF THE WAFFLE SLAB IS GENERALLY RANGE FROM 80 MM TO 100 MM.
➢ THE OVERALL DEPTH OF THE WAFFLE SLAB IS LIMITED TO 300 MM TO 600 MM.
DETAILS

17. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
➢ THE WIDTH OF THE BEAM IN THE WAFFLE SLAB RANGES FROM 100 MM TO 200 MM.
➢ THE SPACING BETWEEN TWO CONSECUTIVE RIBS RANGES FROM 600 MM TO 1500 MM.
➢ WAFFLE SLABS CAN BE REINFORCED WITH THE REBAR FOR ADDITIONAL STRENGTH.
➢ THE REINFORCEMENT IS PROVIDED IN THE WAFFLE SLAB IS PROVIDED IN THE FORM OF A MESH OR INDIVIDUAL BARS.
➢ THE REINFORCEMENT IN THE WAFFLE SLAB IS TWO-DIRECTIONAL.
➢ THE MAIN HORIZONTAL BEAMS ARE CONNECTED BY THE SMALL BEAMS WHICH FORM THE GRID-LIKE PATTERN.

18. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE

19. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
ORTHOGONAL
DIAGRID
3 WAY GRID
FOR TRIANGULAR AND
HEXAGONAL AREAS

20. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE
THE MAIN ELEMENT REQUIRED TO PROVIDE WAFFLE SLAB IS “WAFFLE PODS”.
THERE ARE MANY WAFFLE POD PRODUCERS ALL OVER INDIA.
SOME OF THEM ARE
SUPREME FIBRE GLASS Pvt.Ltd. (MUMBAI).
ENVO PLAST (KOLKATA)
TEKNIK KALIP (MUMBAI & BANGALORE)
UTRACON (GUJARAT)
GEO PLAST (CHENNAI)
MARUTI PLASTICS (MUMBAI)

21. INTRODUCTION
TO
WAFFLE
SLAB
IMPACT
SCHOOL
OF
ARCHITECTURE

22. THANK YOU