LIFT SLAB .pdf
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- 2. WHAT IS LIFTSLAB • ALSO CALLED AS YOUTZ-SLICK METHOD. • CONSTRUCTING CONCRETE BUILDING BY CASTING THE FLOOR OR ROOF SLAB ON TOP OF THE PREVIOUS AND THEN RAISING THE SLAB UP WITH HYDRAULIC JACKS.
- 3. WHAT IS LIFTSLAB • THIS METHOD OF CONSTRUCTION ALLOWS FOR A LARGE PORTION OF THE WORK TO BE COMPLETED AT GROUND LEVEL, NEGATING THE NEED TO FORM FLOOR WORK IN PLACE. • THE ABILITY TO CREATE MONOLITHIC CONCRETE SLABS MAKES THE LIFT SLAB CONSTRUCTION TECHNIQUE USEFUL IN QUICKLY CREATING STRUCTURES WITH REPETITIVE FORM WORK, LIKE PARKING RAMPS. BUILDING WITH RCC SLABS BUILDING WITH LIFT SLABS
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- 5. HISTORY OF LIFTSLAB 1895-1972 1916 –1962 GOT FIRST PATENT ON LIFT SLAB PHILIP N. YOUTZ THOMAS B SLICK
- 6. COMPONENTS OF LIFTSLABS NUT DRIVE ARM TAKE UP NUT HYDAULIC JACK LIFTING ROD ROD COUPLED EXTENSION ROD SPACER LIFTING ANGLE SLAB SHEAR HEAD LIFTING NUT HOLDING NUT
- 7. ADVANTAGES OF LIFTSLAB • ONLY FORMWORK FOR EDGES OF THE SLAB AND NO CENTERING TO SOFFIT OF SLABS IS REQUIRED • THE SLABS ARE CAST MONOLITHICALLY AND CAN BE DESIGNED TO SPAN CONTINUOUSLY BETWEEN THE POINTS OF SUPPORT AND SO EMPLOY THE LEAST THICKNESS OF SLAB. • LIFT-SLAB CONSTRUCTION METHOD BECOMES MORE ADVANTAGEOUS IN BUILDINGS WITH SIMILAR FLOOR PLANS THROUGHOUT THE HEIGHT OF THE BUILDING AND WHERE FLUSH SLAB MAY BE DESIRED. • LIFT-SLAB METHOD MAY BE EMPLOYED WITH RIBBED SLABS NOT ONLY FLAT SLABS WITH SOME COMPROMISE OF THE EASE OF CASTING.
- 8. DISADVANTAGES OF LIFTSLAB • IF NOT PROPERLY HANDLED, THE PRECAST UNITS MAY BE DAMAGED. • IT BECOMES DIFFICULT TO PRODUCE SATISFACTORY CONNECTIONS BETWEEN THE PRECAST MEMBERS. • IT IS NECESSARY TO ARRANGE FOR SPECIAL EQUIPMENT FOR LIFTING AND MOVING OF THE PRECAST UNITS. • THE ECONOMY ACHIEVED IN PRECAST CONSTRUCTION IS PARTIALLY BALANCED BY THE AMOUNT TO BE SPENT IN TRANSPORT AND HANDLING OF PRECAST MEMBERS. IT BECOMES THEREFORE NECESSARY TO LOCATE THE PRECAST FACTORY AT SUCH A PLACE THAT TRANSPORT AND HANDLING CHARGES ARE BROUGHT DOWN TO THE MINIMUM POSSIBLE EXTENT.
- 9. EQUIPMENT USED FORLIFT SLABS HYDRAULIC JACKS • THIS JACK IS A HYDRAULIC PIECE OF EQUIPMENT • THE JACK CAN LIFT SLABS ON COLUMNS LOADED UP TO 100,000 POUNDS AT SPEEDS OF UP TO 14 FEET AN HOUR
- 10. EQUIPMENT USED FORLIFT SLABS LIFTING COLLARS LIFTING COLLARS ARE CAST INTO EACH SLAB AROUND EACH COLUMN PROVIDING A MEANS TO LIFT THE SLAB AND ALSO PROVIDING SHEAR REINFORCEMENT, THEY ARE FIXED TO COLUMNS BY WELDING SHEAR BLOCKS TO PLATES WELDED COLUMN FLANGES AND TO THE COLLAR AFTER THE SLAB HAS BEEN RAISED IN POSITION.
- 11. EQUIPMENT USED FORLIFT SLABS SHEAR BLOCK SHEAR BLOCKS IS A STEEL COMPONENT USED TO HOLD THE LIFTED SLAB IN ITS FINAL ELEVATION.
- 12. EQUIPMENT USED FORLIFT SLABS • IN LIFT-SLAB CONSTRUCTION BOND-BREAKING COMPOUNDS PERMIT THE SLABS TO BE SEPARATED CLEANLY AND EASILY FROM ONE ANOTHER. • BOND BREAKERS INCLUDE WAX DISSOLVED IN A VOLATILE SPIRIT, POLYTHENE SHEET OR BUILDING PAPER MAY ALSO BE USED AS AN ALTERNATIVE. BOND BREAKER • THE MAIN FUNCTION OF BOND BREAKERS IS TO MINIMIZE DYNAMIC LOADS DURING LIFTING OR STRIPPING OF PRECAST MEMBERS AND PERMIT THEIR COMPLETE, CLEAN SEPARATION FROM CASTING SLABS OR MOLDS.
- 13. Sequences of liftslab for 3 storeyed building 1 4 3 2 ALL THE SLABS ( FIRST FLOOR, SECOND FLOOR AND ROOF SLAB ) ARE CAST ON SITE AROUND THE COLUMNS . ROOF SLAB IS RAISED USED JACK AND FIXED AT THE TOP OF COLUMN. BOTH FIRST AND SECOND FLOOR SLABS WERE RAISED AND FIRST FLOOR SLAB IS FIXED AT FIRST . NOW , THE SECOND FLOOR SLAB IS BEEN FIXED.
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- 16. PRE CASTING OFSLABS BEFORE LIFTING
- 17. PRE CASTING OFSLABS
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