USE OF NEW MATERIALS AND TECHNOLOGIES BY CPWD AT

MUMBAI

DR K M SONICHIEF ENGINEER, CPWD, MUMBAI

Post Tensioned Slabs• POST TENSIONED SLABS– CBI OFFICE BUILDING– NISM BUILDINGS (PARTLY)– INCOME TAX BUILDING UNDER CONSTRUCTION– IDBI BUILDING UNDER CONSTRUCTION

Advantages of PT Slab• Material Savings• Reduction in concrete is due to thinner concrete

members.• Reduction in rebar in floor elements.• Reduction in dead load resulting into saving in

concrete and reinforcement of structural members including foundation.

• Saving in building cladding, vertical mechanical/service elements, rebar and concrete in shear walls and other materials due to lesser sizes.

Steps in construction • Design

– The existing design has been based on Presscrete Post-Tensioning System (PPS). Concrete in one member panel shall be placed in one operation continuously without interruption.

• Concreting– Care is taken that the pre-stressing tendons do not get displaced or damaged prior to casting and during

casting. It is ensured that discharge of concrete is not directed onto the pre-stressing tendons. Vibrating is avoided from coming into contact with the pre-stressing tendons whenever possible. Proper compaction of the concrete in anchorage areas is ensured due to high local stresses in these areas and care taken that all the grout hoses remain exposed and protruding from the concrete surface.

• Stressing– After concreting, the carpenter removes the vertical sides end form work. All the stressing recesses are

cleared and pre-stressing barrels and wedges fixed to all pre-stressing castings. When concrete has reached the transfer strength as per the shop drawings (from the results of cube tests), stressing of cables is carried out. All cables are tensioned to the required jacking force and monitored through the pressure gauges.

• Grouting– Excess cable length is cut after the stressing. All pre-stressing tendons are ensured to be flushed with clean

water. Grout is mixed according to the design mix for at least two minutes until a colloidal consistency is produced. The water is put into the container first and the cement is then slowly added. When the cement and water are thoroughly mixed, the non-shrink additive added to the mix. The grout then is injected into the pre-stressing tendons. Grouting is carried out by injection at one end of the duct until clear grout flows out from the other end. The grout hose at the both end is then sealed. Grouting works commence when all scaffolds at a particular storey where grouting works are to be carried out, are removed.

Limitations• Since the cables or tendons in the slab have

been stretched to high tensile strengths, it is extremely important that the slab is not drilled, cut, chiselled or disturb in a way so as to expose the tendons

AAC BLOCKS• LOW DENSITY• GREEN MATERIAL

Service trenches• Not a very new concept• Being adopted in NISM

GFRC PANELS IN FACADE• Can be manufactured in many shapes• Can be painted

STAMPED FINISH CONCRETE

• Can be achieved in desired colours• The process includes – preparation of sub-grade, – placing of forms, – providing reinforcement for stability, – placing the concrete, – screeding and finishing the concrete, – applying colour and – stamping the concrete using desired moulds.

Stamped finish concrete

Innovative Floorings• Wood plastic composite flooring, • Maple hardwood sports flooring for special

applications, • Geofoam block flooring • Crazy patterned flooring of leather finish,

flamed and polished granite • Italian marble flooring

GEOFOAM FLOORING IN STEPS

Seating arrangement of class rooms

Innovative False Ceiling• Acoustic false ceiling • Cloud acoustic false ceiling

ACCOUSTIC FALSE CEILING

• Anutone False ceiling

Double Stack Car Parking

Glass• Structural Glazing• Partitions• Fire resistant Lobbies• Doors• Murals• Solar PV Panels

Dry Stone Cladding

STP

SOLAR ROOF TOP PANELS

AHU ON TOILET SLAB

SYNTHETIC GRASS

FOLDABLE PARTITION

LOUVERS

Energy efficiency• In new buildings only LED fitting or energy

efficient T5 fittings are provided.• Energy efficient Chillers are provided • Solar roof top PV Panels• Recycling waste water• Rain water harvesting

Pumping system• CPWD has adopted hydro-pneumatic

pumping system for water supply in most of large projects.

Green buildings• CPWD is constructing all green buildings and

getting them rated in Mumbai• CBI – 4 star GRIHA• IDBI Belapur – 3 star GRIHA• NISM – 4 star GRIHA• NTH – 3 star GRIHA• Income Tax Building – 4 star GRIHA

CBI OFFICEBUILDING

NATIONAL INSTITUTE OF SECURITIES MARKETS

Student and MDP Hostel blocks

Residential Block

NISM : Images

Orientation Block

Academic Block

Amphitheater

Hostel & MDP Block

Landscape development

Orientation Block

THANK YOU