FLOOR
SYSTEMS
FLAT SLAB
FLAT PLATE
RIBBED FLOOR SLAB
WAFFLE SLAB
LIFT SLAB
SPANSTRESS FLOOR SYSTEM
SLIPFORM METHOD
FLAT SLAB METHOD
A FLAT SLAB IS A TWO-WAY REINFORCED CONCRETE SLAB THAT USUALLY DOES NOT HAVE
BEAMS AND GIRDERS, AND THE LOADS ARE TRANSFERRED DIRECTLY TO THE SUPPORTING
CONCRETE COLUMNS.
THE FLAT PLATE IS A TWO-WAY REINFORCED CONCRETE FRAMING SYSTEM UTILIZING A SLAB OF
UNIFORM THICKNESS, THE SIMPLEST OF STRUCTURAL SHAPES. THE FLAT SLAB IS A TWO-WAY
REINFORCED STRUCTURAL SYSTEM THAT INCLUDES EITHER DROP PANELS OR COLUMN
CAPITALS AT COLUMNS TO RESIST HEAVIER LOADS AND THUS PERMIT LONGER SPANS.
ADVANTAGES
FLEXIBILITY IN ROOM LAYOUT
- PARTITION WALLS CAN BE PLACED ANYWHERE.
- OFFERS A VARIETY OF ROOM LAYOUTS TO THE OWNER.
- FALSE CEILINGS CAN BE OMITTED.
REINFORCEMENT PLACEMENT IS EASIER
- AS REINFORCEMENT DETAILING OF THE FLAT SLAB IS SIMPLE, IT IS
EASIER TO PLACE
EASE OF FRAMEWORK INSTALLATION.
- BIG TABLE FRAMEWORK CAN BE USED IN FLAT SLAB
BUILDING HEIGHT CAN BE REDUCED.
- FLOOR HEIGHT CAN BE REDUCED AND CONSEQUENTLY THE
BUILDING HEIGHT WILL BE REDUCED.
- APPROXIMATELY 10% OF THE VERTICAL MEMBER COULD BE SAVED.
- FOUNDATION LOAD WILL ALSO REDUCE.
LESS CONSTRUCTION TIME
USE OF A BIG TABLE FRAMEWORK HELPS TO REDUCE
CONSTRUCTION TIME
FLAT PLATE METHOD
FLAT PLATE FLOOR SYSTEM IS A REINFORCED CONCRETE FRAME SYSTEM WITH A
UNIFORM THICKNESS THAT IS SUPPORTED DIRECTLY OVER THE COLUMNS OR THE
LOAD-BEARING WALLS. THE FLAT PLATE FLOOR SYSTEM IS A COMMON FLOOR
CONSTRUCTION TYPE EMPLOYED IN THE CONSTRUCTION OF THE BUILDING.
ADVANTAGES DISADVANTAGES
A FLAT PLATE FLOOR SYSTEM THE LATERAL LOAD CAPACITY OF A FLAT
DOES NOT DEMAND ANY BEAM. PLATE FLOOR SYSTEM IS LIMITED
THE USE OF ZERO BEAMS COMPARED TO A MOMENT FRAME.
HELPS TO HAVE UNDERFLOOR THE SPANS EMPLOYED ARE MEDIUM
SPACES AND MORE SERVICE LENGTH
AREAS. SPECIAL REINFORCEMENT FOR SHEAR
MUST BE PROVIDED AT THE COLUMNS OR
THE FLAT PLATE FLOOR SYSTEM
LARGER COLUMNS MUST BE
REQUIRES SIMPLE FORMWORK.
CONSTRUCTED.
THIS SYSTEM IS SUITABLE FOR A
LONG-TERM DEFLECTION IS AN EXPECTED
DIRECT FIX OR SPRAYED
FACTOR THAT REQUIRES FULL LIFE
CEILING.
CONTROL.
THE STRUCTURAL DEPTH OF A A FLAT PLATE FLOOR SYSTEM IS NOT A
FLAT PLATE FLOOR IS MINIMUM. GOOD CHOICE FOR SUPPORTING
REDUCED DEPTH OF SLAB PARTITIONS THAT ARE TOO BRITTLE. FOR
HELPS TO INCREASE THE FLOOR EXAMPLE MASONRY WALLS.
TO FLOOR HEIGHT OF THE A FLAT PLATE FLOOR SYSTEM IS NOT A
BUILDING. GOOD CHOICE TO TAKE UP HEAVY LOADS.
RIBBED
FLOOR
SLAB
RIBBED FLOOR SLAB
A ONE-WAY JOIST FLOOR SLAB CONSISTS OF A SERIES OF SMALL, REINFORCED CONCRETE T
BEAMS THAT ARE CONNECTED WITH GIRDERS THAT IN TURN CARRIED BY THE BUILDING
COLUMN. T BEAMS ARE KNOWN AS JOISTS WHICH ARE FORMED BY SETTING STEEL PAN AT
A CONSTANT SPACING. CONCRETE IS CAST BETWEEN THOSE SPACING TO MAKE THOSE RIBS
AND IN THIS WAY, THE SLAB ALSO CAST AND THE SLAB BECOMES THE FLANGE OF T BEAM.
WAFFLE
SLAB
THE SYSTEM WAS DESIGNED TO DECREASE THE WEIGHT OF TRADITIONAL FULL-CONCRETE SLABS.
THE DOME-SHAPED FORMS CREATE A MATRIX OF VOIDS SURROUNDED BY ORTHOGONAL
RIBBING, PRODUCING A TWO-WAY CONFIGURATION VERY SUITABLE FOR LARGE-SPANNING
SLABS. VOIDS BETWEEN ALL THE DOMES REDUCE THE DEAD LOAD AS THE WIDTH OF THAT
PORTION OF THE SLAB IS LESS THAN A FLAT SLAB. THIS TYPE OF SLAB IS KNOWN AS WAFFLE
SLABS BECAUSE THEY LOOK LIKE WAFFLES WITH ROWS OF BEAMS RUNNING UNDERNEATH THEM.
WAFFLE SLAB SHOWS A CEILING WHICH IS SUITABLE TO INSTALL ALL THE ELECTRICAL
APPLIANCES AND CAN GIVE A BETTER OUTLOOK THUS INCREASING THE AESTHETIC FACTOR.
ADVANTAGES
IN THIS TYPE OF SLAB, THE TENSION STRESS IS ELIMINATED IN THE TENSION SIDE OF THE SLAB. THE
STRENGTH OF CONCRETE IN TENSION IS VERY SMALL AND SO ELIMINATION OF MUCH OF THE TENSION
CONCRETE IS DONE BY THE USE OF PAN FORMS.
ECONOMICAL WHERE THE LIVE LOADS ARE FAIRLY SMALL SUCH AS APARTMENT HOUSES, HOTELS.
LONG SLAB SPANS CAN BE CONSTRUCTED THROUGH RIBBED AND WAFFLE SLABS. IN MANY CASES, LONG
SPANS ARE DESIRABLE IN THE BUILDING. RIBBED OR WAFFLE SLABS ARE AN EASY SOLUTION FOR THIS
PURPOSE.
PROVIDE ARCHITECTURAL ADVANTAGES. ALL THE ELECTRICAL APPLIANCES CAN BE INSTALLED EASILY IN
THE GAP OF THE RIBS WHICH CAN BE ARCHITECTURALLY AESTHETIC.
SLAB THICKNESS OF RIBBED OR WAFFLE SLABS IS LESS THAN OTHER SLAB SYSTEMS. THEREFORE THE
WEIGHT OF SLAB IS REDUCED. THIS SAVING OF WEIGHT CAN CHANGE IN STRUCTURAL CHARACTERISTIC.
LIGHTER AND STIFFER SLAB THAN AN EQUIVALENT FLAT SLAB.
REDUCING THE EXTENT OF FOUNDATIONS BY REDUCING THE ULTIMATE LOAD.
THEY PROVIDE A VERY GOOD FORM WHERE SLAB VIBRATION IS A VIABLE ISSUE.
DISADVANTAGES
NOT SUITABLE WHERE THE LIVE LOADS ARE HUGE AS HEAVY MANUFACTURING BUILDINGS, WAREHOUSES.
THE THICKNESS OF THE SLAB IS CONTROLLED AS THE REQUIREMENT OF FIRE RESISTANCE.
FORMWORK COST IS HIGH.
SOMETIMES DIFFICULT TO INSTALL THE ELECTRIC EQUIPMENT.
LIFT SLAB METHOD
LIFT-SLAB CONSTRUCTION IS A PRECAST METHOD OF CONSTRUCTION OF SLAB ON THE GROUND AND THEN LIFTING IT TO
THE STRUCTURE. A TYPE OF PRECASTING USED IN BUILDING CONSTRUCTION INVOLVES CASTING FLOOR AND ROOF SLABS
AT OR NEAR GROUND LEVEL AND LIFTING THEM TO THEIR FINAL POSITION, HENCE THE NAME LIFT-SLAB CONSTRUCTION.
IT OFFERS MANY OF THE ADVANTAGES OF PRECASTING AND ELIMINATES MANY OF THE STORING, HANDLING, AND
TRANSPORTING DISADVANTAGES. IT NORMALLY REQUIRES FEWER JOINTS THAN OTHER TYPES OF PRECAST BUILDING
SYSTEMS. TYPICALLY, COLUMNS ARE ERECTED FIRST, BUT NOT NECESSARILY FOR THE FULL HEIGHT OF THE BUILDING.
NEAR THE BASE OF THE COLUMNS, FLOOR SLABS ARE CAST IN SUCCESSION, ONE ATOP ANOTHER, WITH A PARTING COM-
POUND BETWEEN THEM TO PREVENT BOND. THE ROOF SLAB IS CAST LAST, ON TOP. USUALLY, THE CONSTRUCTION IS
FLAT PLATE, AND THE SLABS HAVE UNIFORM THICKNESS; WAFFLE SLABS OR OTHER TYPES ALSO CAN BE USED.
LIFT SLAB METHOD
IN THIS TECHNOLOGY, THE FOUNDATIONS OF THE BUILDING ARE
BROKEN UP AND REMOVED WITH SMALL EXCAVATORS. THE NATURAL
GROUND IS STABILIZED AND IF REQUIRED AND A NEW FOUNDATION OR
CONCRETE SLAB IS INSTALLED. THE BUILDING IS THEN INSTALLED BACK
ON THE NEW FOUNDATION AND SECURED.
RCC HOUSES ARE EASIER TO LIFT. MASONRY HOUSES ARE ALSO SHIFTED,
BUT IT IS MORE CHALLENGING TO LIFT SUCH HOUSES BECAUSE OF THEIR
DESIGN, CONSTRUCTION AND WEIGHT.
SPANTRESS AND SLIPFORM METHOD
SPANTRESS METHOD
A CONSTRUCTION METHOD WHICH UTILIZES SPAN-STRESS PRESTRESSED T- JOIST
THAT CAN BE USED WITH FILLER BLOCKS OR COLLAPSIBLE STEEL FORMS, OR
PLYWOOD FORMS.
THE SYSTEM HAS THE STIFFNESS OF A CONVENTIONAL SLAB SINCE THE
CONCRETE WAS POURED MONOLITHIC AND IS CONNECTED WITH THE
STRUCTURE BY PROVIDING CONNECTION REINFORCEMENT THAT WILL TRANSFER
THE LATERAL FORCES TO THE LATERAL LOAD RESISTING MEMBERS.
A SYSTEM THAT IS LIGHT YET CAPABLE OF HEAVY LOADS AND LONG SPANS
MUCH ECONOMICAL COMPARED TO CONVENTIONAL CAST-IN-PLACE CONCRETE
SLAB.
LENGTH GOES FROM 3.00 METERS TO 9.00 METERS.
SLIPFORM METHOD
SLIPFORM IS A CONSTRUCTION METHOD FOR REINFORCED CONCRETE WALLS, GENERALLY
LIFT AND STAIR CORE WALLS, AND IS OFTEN ECONOMICAL FOR BUILDINGS MORE THAN TEN
STOREYS IN HEIGHT. SLIPFORM INVOLVES THE FORMWORK FOR THE WALLS BEING RAISED IN
A CONTINUOUS PROCESS AS THE WALL CONCRETE IS POURED. AS THE SLIP FORM RIG IS
RAISED, IT IS SUPPORTED BY ALREADY CAST CONCRETE WALLS BELOW.
