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SYSTEM FORMWORK Larsen and toubro limited

Presentation by:

Rachna Rajput

(1030227)

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LARSEN & TOUBRO LIMITED

ECC DIVISION

LUDHIANA CITY CENTRE

CONSTRUCTION OF RCC BASEMENT STRUCTURE

By : A.K. Mishra

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THE CLIENT: TODAYHOMES AND INFRASTRUCTURE JOINT VENTURE WITH LUDHIANA IMPROVEMENT TRUST

ARCHITECT: CP KUKREJA AND ASSOCIATES

CONTRACTOR : LARSEN AND TOUBRO LIMITED

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LUDHIANA CITY CENTRE

LOCATED IN HEART OF LUDHIANA BUILT ON 25 ACRES OF LAND 4 SIDE OPEN PLOT MAXIMUM NUMBER OF CAR PARKS UNDER

ONE ROOF ONLY DEVELOPMENT OF INDIA WITH 5 STAR

HOTEL,SHOPPING MALL,IT/OFFICE SPACE,HEALTH CARE,LIBRARY,MUESEAM UNDER 1 ROOF

BIGGEST ATRIUM:2 LAKH SQUARE FEET

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LUDHIANA CITY CENTRECONSTRUCTION OF RCC BASEMENT STRUCTURE

Project Highlights

JOB VALUE : 12400 lacs DATE OF LOI: 30:1:2006 DATE OF COMMENCEMENT: 15:02:2006 DATE OF COMPLETION: 14:02:2007 DURATION OF PROJECT : 12 months

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THE WORK

FORMWORK PLANNING AND

DESIGN OF ITS VARIOUS

COMPONENTS

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WHAT IS FORMWORK? FORMWORK IS A MOULD USED TO SHAPE

CONCRETE UNTIL IT ATTAINS SUFFICIENT STRENGTH TO CARRY ITS OWN WEIGHT

CAN BE ASSEMBLED BY UNSKILLED LABOUR

CONSTITUTES 30% OF THE COST AND 60% OF THE TIME IN CONCRETE CONSTRUCTION

GOOD FORMWORK RESULTS IN SPEED,QUALITY,ECONOMY AND SAFETY

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TRADITIONAL APPROACH

BALLIES USED AS SUPPORT FOR SHUTTERING

UNSAFE AND UNRELIABLE

LOW REUSE VALUE

DOES NOT PRODUCE GOOD QUALITY CONCRETE

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CHOICE OF RIGHT TYPE OF FORMWORK

FORMWORK SHOULD BE ABLE TO BE DESHUTTERED AND DISMANTLED FAST

SAFETY TO BE IMPROVED BY SITE PERSONNEL

OVERALL COST SAVINGS GOOD SURFACE FINISH TO BE ACHIEVED OPTIMUM STOCK OF FORMWORK FOR SIZE

OF WORKFORCE AND SPECIFIED TIME SCHEDULE

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SYSTEM FORMWORK-L&T

EARLIER CALLED DOKA FORMWORK

INVERSIBLE FAST ERECTION MORE STABLE SAFE IN USE

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FORMWORK PLANNINGSTEP1.) CONFIRMING HQ ON THE NEW JOBS BAGGED IDENTIFYING TIME AND MATERIALS FOR

CONSTRUCTION PROJECTSTEP2.) FINALIZING FORMWORK MATERIALS

REQUIREMENTS FOR THE PROJECT COLLATE THE REPORTS FROM RUNNING SITES

AND CHECK SEPARABILITY FROM OTHER SITES WITHIN THE REGION

SENDING REQUEST FOR TRANSFER OF RESOURCES IF AVAILIBILIY IS CONFIRMED

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CONTD….

RECEIVING NEW TARGETS ON PRODUCTIVITY FROM HQ

COMPARING THE RUNNING LMP COST FROM THE ACTUAL

IDENTIFYING TRAINING NEEDS OF STAFF

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COMPONENT DETAILING FOUNDATION FORMWORK

HDT TOWER

SLAB/BEAM FORMWORK

WALL/COLUMN FORMWORK

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FOUNDATION FORMWORK

STEEL PANELS OF STANDERED SIZES MINIMIZE MAKING AT SITE

USE OF VERSATILE COMPONENTS LIKE STEEL WALERS(2 ISMC BACK 2BACK) AND ALIGNMENT PROPS

EASY ASSEMBLY WITH DIMENSIONAL ACCURACY

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FOUNDATION FORMWORK MATERIAL CONTD.

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CONTD…

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CONTD….

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AFTER ERECTION

Steel panel

Pipe waler

Alignment prop

welar

Pipe waler clamp

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HDT TOWER BASIC FRAME HORIZONTAL BRACE DIAGNOL BRACE TAKES LOAD OF 250KN HIEGHT ADJUSTMENTS UPTO 800MM

POSSIBLE TRANSPORT DEVICES CAN BE ATTATCHED

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COMPONENT DETAILING

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CONTD….

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AFTER ERECTION

Coupler and spring lock pin

Foot plate

Tower spindle

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WALL/COLUMN FORMWORK

SHOP MADE SHUTTER

ACCORDING TO THE HIEGHT OF WALL OR COLUMN SPLICING CAN BE DONE

ISMC WALERS ARE USED FOR BEARING

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COMPONENT DETAILING

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CONTD….

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CONTD……

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COLUMN FORMWORK WORKING AT 4.8M HIEGHT

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COLUMN FORMWORK

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WALL FORMWORK 1.8M HIEGHT

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SLAB/BEAM FORMWORK SHEATHING MEMBER

H-BEAM(SECONDARY MEMBER)

WELAR(PRIMARY MEMBER)

HDT TOWER

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AFTER ERECTION

tower

H-beam

Sheathing

welar

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DESIGN OF FORMWORK FORMWORK MUST SUPPORT ALL THE

VERTICAL AND LATERAL LOADS ALL LOADS ARE ASSUMED TO BE

UNIFORMLY DISTRIBUTED BEAMS SUPPORTED OVER 3 OR MORE

SPANS ARE TAKEN AS CONTINUOUS APPROXIMATE FORMULAE ARE USED

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AN IMPORTANT POINT

SHEATHING SPAN DECIDES H-BEAM SPACING

H-BEAM SPAN DECIDES WALER SPACING

WELAR SPAN DECIDES TOWER SPACING

“SPAN” HERE MEANS THE DISTANCE BETWEEN TWO REACTION POINTS

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DESIGN PROCEDUREEXAMPLE

LOADS TO BE TAKEN

DEAD LOAD(1)

(THICKNESS OF MEMBER*DENSITY OF

CONCRETE)

LIVE LOAD(2)

SELF WEIGHT(3)

DESIGN LOAD,W=(1)+(2)+(3)

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DESIGN PROCEDURECHECKS TO BE APPLIED

BENDING MOMENT CONDITION SHEAR FORCE CONDITION DEFLECTION CONDITION THE MINIMUM OF ALL 3 SPANS IS

TAKEN AS SPAN FOR THE MEMBER ACCORDING TO HEIGHT OF WALL OR

COLUMN THE REQUIRED LENGTH OF H-BEAM(AN I SECTION )

HIGH STRENGTH TIE SYSTEM BEAR LARGE CONCRETE PRESSURE

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DESIGN PROCEDURECONTD….

DESIGN DONE FROM TOP TO BOTTOM 1. SHEATHING MEMBER 2.H-BEAM(SECONDARY MEMBER) 3.WELAR(PRIMARY MEMBER) HDT TOWER

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SELF WEIGHT OF CONCRETE WITH REINFORCEMENT=25KN/M^3

SELF WEIGHT OF FORMWORK VARIES BETWEEN 0.5KN/M^2 TO .75KN/M^2

MINIMUM LIVE LOAD =2.5KN/M^2

MINIMUM DESIGN LOAD=5.0 KN/SQM

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SHEATHING MEMBER:

END CONDITION ASSUMED TO BE A PROPPED

CANTILEVER BM=W*L^2/8<=.2KNM/M

SHEAR=5*W*L/8<=6.16KN/M

DEFLECTION=W*L^4/(185*E*I)<=1.852*10^-3M

MINIMUM OF ABOVE THESE 3 SPANS IS TAKEN

AS SPACING BETWEEN H-BEAMS

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SECONDARY MEMBER(H BEAM):

END CONDITION IS ASSUMED TO BE SIMPLY

SUPPORTED LOAD INTENSITY =DESIGN LOAD*SPAN OF

SHEATHING MEMBER BM=W*L^2/8<=3KNM SHEAR=W*L/2<=6KN DEFLECTION=5*W*L^4/(384*E*I)

MINIMUM OF ALL 3 IS TAKEN AS SPAN FOR

H-BEAM

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WELAR (PRIMARY MEMBER)

SIMPLY SUPPORTED END CONDITION IS

ASSUMED NOW WIDTH OF LOADING IS THE SPAN FOR

H-BEAM AND W=DESIGN LOAD*WIDTH OF LOADING

BM=W*L^2/8<=12.67KNM/M SHEAR=W*L/2<=103.4KN/M DEFLECTION=5*W*L^4/(384*E*I)<=6.67*10^-3

MINIMUM OF THESE 3 IS TAKEN AS THE DISTANCE BETWEEN 2 TOWERS

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DESIGN FOR WALL/COLUMN FORMWORK

CONCRETE EXERTS A FLUID PRESSURE Dh ON THE FORMWORK

Pmax=

D[C1*R^.5-(C2*K*(H-C1*R^.5)^.5) OR

Dh

whichever is smaller

VALUE OF C1

FOR WALLS=1

FOR COLUMNS=1.5

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VALUE OF C2 DEPENDS ON CONSTITUENT MATERIALS OF CONCRETE

D=WEIGHT DENSITY OF CONCRETE H=VERTICAL FORM HIEGHT h=VERTICAL POUR HIEGHT K=TEMPERATURE COEFFICIENT TAKEN AS

(36/T+16)^2 R=RATE OF RISE M/H T=TEMPERATURE OF CONCRETE AT PLACING

(degree celsius)

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PRESSURE DISTRIBUTION DIAGRAM

H

P max

Pmax/D

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DESIGN OF WALER –DESIGNED AS LATERALLY UNSUPPORTED BEAM

SIGMAbc=.66*Fcb*Fy/(Fcb^n+Fy^n)^1/n

Fcb=ELASTIC CRITICAL STRESS(N/MM^2)

Fy= YIELD STRESS OF STEEL IN( N/MM^2)

N=FACTOR TAKEN AS 1.4 Fcb=K1*(X+K2*Y)*C2/C1 PERMISSIBLE SHEAR STRESS=0.4*Fy PERMISSIBLE DEFLECTION=L(SPAN)/325 BENDING STRESS=M/Z SHEAR STRESS=F/Aweb

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STRIPPING TIME FOR FORMWORK

VERTICAL FORMWORK TO COLUMN, WALL AND BEAM :16-24HOURS

SOFFIT FORMWORK TO SLABS(PROPS TO BE

REFIXED AFTER REMOVAL OF FORMWOK) :3DAYS

SOFFIT FORMWORK TO BEAMS :7DAYS

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SAFETY IN FORMWORK BEFORE ERECTION OF STEEL FRAME

STAGING THOROUGH INSPECTION DIAGNOL BRACES SHOULD BE IN PROPER

POSITION ALL CONNECTING DEVICES SHOULD BE IN

PLACE BRACING SHOULD BE PROVIDED IF TOWER

HEIGHT INCREASES 6M AT HIEGHTS SAFETY BELTS SHOULD BE

USED BY WORKMEN

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Ladder Safety

Follow the 4:1 rule when using extension ladders

6 m (20 ft)

1.5 m (5 ft.)

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–Erect First Tower – Adjust and ensure the

top level is same. Connect all pin bracing

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Use of lifeline above 2m

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LABOUR PRODUCTIVITY

PRODUCTIVITY IS MAXIMUM OUTPUT FROM MINIMUM INPUT

UNITS ARE SQM/MANDAY

WORKING OF 8 HRS=1MANDAY

PRODUCTIVITY= SHUTTERING AREA ACHIEVED DURING THE

MONTH/MANDAYS

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MATERIAL PRODUCTIVITY

MATERIAL PRODUCTIVITY IS COMPARED WITH STANDERED PRODUCTIVITY

STANDERED PRODUCTIVITY CALCULATED ON THE BASIS OF SHUTTERING AREA COMPLETED AND KG MONTH PER SQM

TOTAL REQUIRED KG=

SHUTTERING AREA *KG MONTH PER SQM

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ACTUAL PRODUCTIVITY IS TAKEN AS AVERAGE STOCK LEFT

PRODUCTIVITY IN %=

(ACTUALPRODUCTIVITY/STANDERED PRODUCTIVITY)*100

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RATE ANALYSIS

ON THE BASIS OF NUMBER OF CARPENTER KHALASI AND HELPER,NUMBER OF HOURS OF WORK AND RATE/HR THE TOTAL AMOUNT IS CALCULATED FOR SHIFTING ,FIXING AND REMOVING

PRODUCTIVITY IN SQM/MANDAYS IS CALCULATED

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BATCHING OF CONCRETE

PAN TYPE BATCHING PLANT CAPACITY OF 60M^3/HR WEIGHED BATCHING MIXING TRANSPORTATION PLACING

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THANK YOU