Bubble deck slab ppt
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This document provides an overview of bubble deck slabs. It describes bubble deck slabs as a method that virtually eliminates concrete from the middle of floor slabs, replacing it with hollow plastic spheres to reduce weight by 30-50%. This makes construction faster and reduces loads on foundations. Three main types - filigree elements, reinforcement modules, and finished planks - are described. Experimental results show bubble deck slabs have 80% of solid slab shear strength and 5% more deflection, but are 40% lighter. Advantages include reduced material needs, costs, and CO2 emissions. Future uses could include tall buildings, large spans, and parking areas.
![REFERENCES
• [I] Tina Lai "Structural behavior of bubble deck slab and their
applications to lightweight bridge decks" ,M.Tech thesis, MIT, 2009.
• Arati Shetkarand & Nagesh Hanche an Experimental Study On
bubble deck slab system with elliptical balls, NCRIET-2015
&Indian J.Sci.Res. 12(1):021-027, 2015
• [3] Martina Schnellenbach-Held and Karsten Pfeffer,"Punching
behavior of biaxial hollow slabs" Cement and Concrete Composites,
Volume 24, Issue 6, Pages 551-556, December 2002
• [4] Sergiu Calin, Roxana Glntu and Gabriela Dascalu, "Summary of
tests and studies done abroad on the Bubble deck slab system", The
Buletinul Institutului Politehnic din LV (LIX), f. 3, 2009](https://image.slidesharecdn.com/bubbleds-170408171346/85/Bubble-deck-slab-ppt-28-320.jpg)
Bubble deck slab ppt
- 2. contents • Abstract • Introduction • Type of bubble decks • Example of projects • Effect • Materials • Why bubble deck slab • Shear • Bending strength • Durability • Deflection • Vibration • Fire resistance • advantages • Experimentation and results • Scope of future use • Conclusions • reference
- 3. Abstract Bubble deck slab is a method of virtually eliminating all concrete from the middle of a floor slab, which is not performing any structural function, thereby dramatically reducing structural dead weight.
- 4. • High density polyethylene hollow spheres replace the in- effective concrete in the centre of the slab, thus decreasing the dead weight and increasing the efficiency of the floor. • By introducing the gaps leads to a 30 to 50% lighter slab which reduces the loads on the columns, walls and foundations, and of course of the entire building. • The advantages are less energy consumption - both in production, transport and carrying out, less emission - exhaust gases from production and transport, especially Co2.
- 5. INTRODUCTION • BUBBLE deck slab is a biaxial hollow core slab invented in Denmark. It is a method of virtually eliminating all concrete from the middle of a floor slab not performing any structural function thereby dramatically reducing structural dead weight. • Bubble deck slab is based on a new patented technique which involves the direct way of linking air and steel. • Void forms in the middle of a flat slab by means of plastic spheres eliminate 30%-50%of a slab's self-weight removing constraints of high dead loads and short spans Its flexible layout easily adapts to irregular and curved plan configurations. • The system allows for the realization of longer spans, more rapid and less expensive erection, as well as the elimination of down-stand beams. • The Bubble deck slab floor system can be used for storey floors, roof floors and ground floor slabs.
- 6. • Since the weight of the structure reduced, this type of structure can useful to reduce earthquake damage. • Bubble deck slab is composed of three main materials they are steel, plastic spheres and concrete. • 1) Concrete :The concrete is made of standard Portland cement with max aggregate size of 20mm.No plasticizers are necessary for concrete mixture. • 2) Steel :The steel reinforcement is of grade Fy60 strength or higher. The steel is fabricated in two forms - meshed layers for lateral support and diagonal girders for vertical support of the bubbles. • 3) Plastic spheres :The hollow spheres are made from recycled high-density polyethylene or HDPE.
- 7. Types of Bubble Deck Type A- Filigree Elements Type B- Reinforcement Modules Type C- Finished Planks Type-A is a combination of constructed and unconstructed elements. A 60 mm thick concrete layer that acts as both the formwork and part of the finished depth is precast and brought on site with the bubbles and steel reinforcement unattached. The bubbles are then supported by temporary stands on top of the precast layer and held in place by a honeycomb of interconnected steel mesh. Additional steel may be inserted according to the reinforcement requirements of the design. The full depth of the slab is reached by common concreting techniques and finished as necessary. Type A:- Filigree Elements
- 8. Type B:-Reinforcement Modules • A reinforcement module one which consists of a pre-assembled sandwich of steel mesh and plastic bubbles, or "bubble lattice“. • These components are brought to the site, laid on traditional formwork, connected with any additional reinforcement, and then concreted in place by traditional methods.
- 9. Type C:- Finished Planks • Is a shop-fabricated module that includes the plastic spheres, reinforcement mesh and concrete in its finished form. • The module is manufactured to the final depth in the form of a plank and is delivered on site. • Requires the use of support beams or load bearing walls. This class of Bubble Deck is best for shorter spans and limited construction schedules.
- 10. • The first high rise building erected with Bubble Deck filigree elements and the second highest building in Netherlands, 34 stories and 131 meter high. • Bubble Deck was chosen, in spite of being a completely new product, because of its advantages in cost , construction time and flexibility and because of environmental issues. Beams could be excluded resulting in two more stories than planned in the beginning for the same building height. Built in 1998-2000. Examples of Project Millenium Tower Rotterdam
- 11. Effect• The basic effect of the bubbles is the weight reduction of the deck. The dead load of the Bubble Deck is 1/3 lesser than a solid deck with the same thickness – and that without effecting the bending strength and the deflection behavior of the deck.
- 12. MATERIALS STEEL –The steel reinforcement is of MS or HYSD can be used. PLASTIC SPHERES •hollow spheres made from recycled high density polyethylene. • Enough strength & rigidity. • Not porous. • Doesn’t react chemically with concrete or steel. CONCRETE-the concrete is made of standard Portland cement with max aggregate size of ¾ inch.
- 13. WHY BUBBLE DECK SLAB ? No compromise for strength& serviceability Flat slab technology (no need of beams ) Longer spans Pre fabricated & cast in-situ
- 14. Shear • The main difference between a solid slab and a voided biaxial slab refers to shear resistance. Due to the reduced concrete volume, the shear resistance will also be reduced. • Near the columns, bubbles are left out so in these zones a Bubble deck slab is designed exactly the same way as a solid slab. Shear resistance of Bubble deck slab is 0.6 times the shear resistance of a solid slab of the same thickness . • In practice, the reduced shear resistance will not lead to problems, as balls are simply left out where the shear is high, at columns and walls.
- 15. Bending strength • Bubble Deck when compared to a solid deck, both practically and theoretically. • The results in the table below shows that for the same deck thickness, the bending strength is same for Bubble Deck and for a solid deck and that the stiffness of the Bubble Deck is slightly lower. • Bending stresses in the Bubble Deck slab are found to be 6.43% lesser than that of solid slab.
- 16. • The ultimate load value obtaining bending tests were upto 90% greater than the ultimate load value. The bottom reinforcement steel and the top compressive portion of stress block contributes to flexural stiffness in the bending.
- 17. Durability • The durability of bubble deck slab is not fundamentally different from ordinary solid slabs. • Bubble deck slab joints have a chamfer on the inside to ensure that concrete surrounds each bar and does not allow a direct route to air from the rebar surface. This is primarily a function of the fire resistance but is also relevant to durability. • Cracking in Bubble deck slab is not worse, and probably better, than solid slabs designed to work at the same stress levels. • Bubble deck slab possesses a continuous mesh, top and bottom, throughout the slab and this ensures shrinkage restraint is well provided for and that cracking is kept to a minimum .
- 18. Deflection • Deflection of Bubble Deck is 5.88% more than solid slab as the stiffness is reduced due to the hollow portion. • Strengthened Bubble Deck has low deflection compare to un strengthened Bubble Deck slab. • Conventional slab carried the stress of about 30.98 MPa by applying the udl load of about 340 kN and causes deflection of 12.822 mm. • The Bubble Deck slab carried the stress of about 30.8 MPa by applying the udl load of about 320 kN and causes deflection of 14.303mm.
- 19. • The Bubble Deck slab can withstand 80% of stress when compared with conventional slab. • Slide variation occurs in the deformation when compared to conventional slab.
- 20. Vibration • RC slab structures are generally less susceptible to vibration problems compared to steel framed and light weight skeletal Structures, especially using thin slabs. • However, Bubble deck slab is light and is not immune from vibration in all cases so this must be checked just as it should be in appropriate solid slab applications. • The most effective weapons against vibration particularly resonant vibration, are stiffness and damping. • If we consider damping to be similar to solid slabs, and concentrate on stiffness, we may observe that a Bubble deck slab can provided over 2 times the stiffness obtained from a solid slab for the same quantity of concrete used.
- 21. Fire resistance • The fire resistance of the slab is a complex matter but is chiefly dependent on the ability of the steel to retain sufficient strength during a fire when it will be heated and lose significant strength as the temperature rises. • The temperature of the steel is controlled by the fire and the insulation of the steel from the fire. • In an intense, prolonged fire, the ball would melt and eventually char without significant or detectable effect • Fire resistance depends on concrete cover nearly 60-180 minutes. • Smoke Resistance is about 1.5 times the fire resistance. • Balls simply carbonize. No toxic gasses will be released.
- 22. Advantages • Structural • Less weight. • Increased strength. • No need of beams. • Only few columns required. • Larger span. • Free choice of Shape. • Less foundation depth. • Less excavation required. 15 M
- 23. • Construction • Light in weight less equipment is required. • Easy incorporation of ducts and pipes into slab. • Less work on construction site. • Engineering • The biaxial flat slab system and columns are ideal for structures with high resistance against Explosions. • These slabs and column system acts as an elastic membrane which transfer horizontal forces to stiff vertical structures which is used for Earthquake resistant designs.
- 24. • Environment • Less material and energy consumption. • Reducing Co2 emission up to 40 kg/m2. • 1kg of plastic replaces 100kg of concrete. • Every component can be recycled. • Economy • Savings in materials. • Transportation costs reduced. • Faster construction time. • Buildings can be more flexible and easy in installations.
- 25. Experimental studies 1.Shear strength- 80% of solid deck slab 2.Deflections - 5% more as solid deck 3.Weight - 40% less than a solid slab 4.Fire resistance - 65% of solid slab
- 26. Scope of future use • Used for constructing all types of building especially sky scrapers. • Best for larger span halls like theatres and auditoriums. • Pedestrian bridge decks. • Used in parking areas as less number of columns are required.
- 27. Conclusion • Weight reduction is 50% compared to solid. • The bubble deck technology is environmentally green and sustainable; avoiding the cement production allows reducing global Co2 emissions. • In comparative of conventional slab the volume of concrete in bubble deck (continuous) are less required, that is 25% approximate. • Cost and time saving by using bubbles in the slab like weight of slab, concrete volume indirectly load on the beam and walls also decrease/ less so that building foundations can be designed for smaller dead loads.
- 28. REFERENCES • [I] Tina Lai "Structural behavior of bubble deck slab and their applications to lightweight bridge decks" ,M.Tech thesis, MIT, 2009. • Arati Shetkarand & Nagesh Hanche an Experimental Study On bubble deck slab system with elliptical balls, NCRIET-2015 &Indian J.Sci.Res. 12(1):021-027, 2015 • [3] Martina Schnellenbach-Held and Karsten Pfeffer,"Punching behavior of biaxial hollow slabs" Cement and Concrete Composites, Volume 24, Issue 6, Pages 551-556, December 2002 • [4] Sergiu Calin, Roxana Glntu and Gabriela Dascalu, "Summary of tests and studies done abroad on the Bubble deck slab system", The Buletinul Institutului Politehnic din LV (LIX), f. 3, 2009
- 29. THANK YOU For your attention