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SYSTEM FORMWORK Larsen and toubro limited

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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 PROJECT

STEP2.)

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/STANDE

RED 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