A Seminar On Affordable Rapid Mass Housing Using Gfrg s 69p23

Affordable Rapid Mass Housing Using GFRG s

Guided By: Prashant Kumar Nayak

Presented By: Suman Pati

ABSTRACT • There is a huge growing requirement of building materials in India due to the existing housing shortage of 24.7 million units{ 2007} mainly for the low income groups in urban India. • Estimated urban housing shortage in 2012 is 26.53 million, while the housing shortage of rural India in 2012 is 42 million units. Thus total estimated housing shortage for Urban & rural India in 2012 is 68.53 million units. • To meet this challenge, India requires innovative, energy efficient building materials for strong and durable housing in fast track method of construction at affordable cost. It is also important that housing and buildings are disaster resistant to protect the lives and properties of people.

INTRODUCTION TO GFRG The building industry s for 40% of CO2 emissions. GFRG is an energy efficient green building material with huge potential for use as load bearing and non load bearing wall s. GFRG is a large load bearing with modular cavities suitable for both external, internal walls as well as floor slab or roof slab in combination with RCC as a composite material. Rapidwall buildings are resistant to earthquakes, fire and cyclones. Rapidwall s based on construction manual prepared by IIT Madras to suit Indian situation. FACT & RCF, two fertilizer giants under public sector are together setting up Rapidwall and plaster products manufacturing plant at Ambalamugal using Rapidwall technologies of Australia called FACT RCF Building products Ltd. (FRBL). FACT has about 7 million tons of industrial by product gypsum. Glass fiber reinforced gypsum is made up of glass fiber and gypsum wastage from fertilizer industry.

PHYSICAL AND MATERIAL PROPERTIES Rapidwall is world’s largest load bearing lightweight s. The s are manufactured with size 12 m length, 3m height and 124 mm thickness. Each has 48 modular cavities of 230 mm x 94 mm x 3m dimension. The density is 1.14g/cm3 , being only 10-12% of the weight of comparable concrete /brick masonry. The physical and material properties of s are as follows:

Weight Axial load capacity

44 Kg/ sqm 160 kN/m{ 16 tons/ m}

Compressive strength

73.2 Kg/cm2

Flexural strength

21.25 kg/cm2

Tensile Strength

35 KN/ m

Fire resistance

4 hr rating withstood 700-10000 C

Elastic Modulus

3000-6000Mpa

Water absorption

< 5%

MANUFACTURING OF GFRG

TRANSPORTATION AND LIFTING s are vertically loaded at the factory on stillages for transport to the construction sites on trucks. Each stillage holds 5 or 8 pre-cut s. The stillages are placed at the construction site close to the foundation for erection using vehicle mounted crane or other type of crane with required length for construction of low, medium and high rise buildings. Special lifting jaws suitable to lift the ,are used by inserting into the cavities and pierced into webs, so that lifting/handling of s will be safe.

TS AND CAVITIES Wall to wall ‘L’, ‘T’, ‘+’ angle ts and horizontal wall ts are made by cutting of inner or outer flanges or web appropriately and infill of concrete with vertical reinforcement.

CONSTRUCTION PROCEDURE FOUNDATION: For Rapidwall Housing a conventional foundation like spread footing, RCC column footing, raft or pile foundation is used as per the soil condition and load factors. All around the building RCC plinth beam is provided. Conventional water proofing materials are used in the foundation

RAPAID WALL: Rapidwall enables fast track method of construction. Conventional building construction involves various time consuming processes, like i) masonry wall construction ii) cement plastering requiring curing, iii) casting of RCC slabs requiring centering and scaffolding and curing iv) removal of centering and scaffolding and v) plastering of ceilings and so on. Construction time is minimized to 15-20% by the rapid wall method. Instead of brick by brick construction, Rapidwall enables wall by wall construction. Rapidwall also does not require cement plastering as both surfaces are smooth and even and ready for application of special primer and finishing coat of paint. OPENINGS: Door/window/ventilator, openings will be cut and reinforced concrete is provided there.

LINTEL: Embedded RCC lintels are to be provided wherever required by cutting open external flange. Reinforcement for lintels and RCC sunshades can be provided with required shuttering and .

CONCRETE INFILL : After inserting vertical reinforcement rods as per the structural design and clamps for wall corners are in place to keep the wall s in perfect position, concrete of 12mm size aggregate will be poured from top into the cavities. There is no need to use vibrator because gravitational pressure acts to self compact the concrete inside the water tight cavities. Generally every third cavity should be concreted.

TIE BEAM: An embedded RCC tie beam to floor/roof slab is to be provided at each floor/roof slab level, as an essential requirement of national building code against earth quakes. For this, web portion to required beam depth at top is to be cut and removed for placing horizontal reinforcement with stirrups and concreted.

ROOF SLAB: Instead of a solid concrete floor slab, which is typically 100 to 150mm thick, the GFRG s are used. They are placed horizontally over the walls in different roofs. The roofs typically spanning along the shorter direction. Concrete tie beams connect the s to the walls at all junctions. Every third cavity in the horizontal GFRG is cut open from the top and reinforced cage is inserted to serve as a concealed beam. Further a steel welded mesh is placed on top of the entire floor slab and subsequently embedded in screed of concrete 50mm thick. The advantage with the system over conventional concrete slabs is the there is no need of shuttering and the finish at bottom is excellent. It also not required any plastering. Conduits for electrical work are kept in place before concreting the slab.

STAIR CASE: The stair case work is taken up using GFRG s as the landing slab with reinforced concrete bars in all the cavities.

FINISHING WORK: Once concreting of ground floor roof slab is completed, on the 4th day, wooden planks with props in ground floor can be removed. Finishing of internal wall corners and ceiling corners etc can be done using wall putty or special plaster by experienced plasterers. Simultaneously, electrical work, water supply and sanitary work, floor tiling, mosaic or marble works, staircase work etc can also be carried out. Every upper floor can be finished in the same way.

COMPERISON Comparative study of Rapidwall building and conventional building (For 2storey 1500 sft): Materials/ items

Rapidwall Building Conventional Building

Saving in %

Cement

16 tons

32.55 tons

50.8

Steel

1800 kg

2779 kg

35.2

Sand

20cum

83.37cum

76

Granite

38cum

52.46cum

27.56

Bricks

-

57200

GFRG

500sqm

-

Water

50000ltr

200000ltr

75

Labour

389 mandays

1200 mandays

67.59

Construction time

21 days

120 days

82

Wt. of superstructure

170 tons

490 tons

65

Construction cost

Rs 13.25 lakhs

Rs 18.27 lakhs

61.5

CONCLUSION Rapidwall provides a new method of building construction in fast track, fully utilising the benefits of prefabricated, light weight large s with modular cavities and by the use of concrete and steel reinforcement. By this process, man power, cost and time of construction is reduced. The use of scarce natural resources like river sand, water and agricultural land is significantly reduced. Rapidwall buildings thereby reduce burdening of the environment and help to reduce global warming. Rapidwall use also protect the lives and properties of people as these buildings will be resistant to natural disasters like earthquakes, cyclone, fire etc. This will also contribute to achieve the goal of much needed social inclusive development due to its various benefits and advantages with affordability for low income segments also. Fast delivery of mass housing is very critical for reducing huge urban housing shortage in India. Rapidwall s will help to achieve the above multiple goals.

THANK YOU…