bridge launching girder - lecture notes

8/11/2019 Bridge Launching Girder - Lecture Notes

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AFCONS Infrastructure Limited Report of Class Room at HO (Lecture- 2)

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Classroom at HO, Lecture series

Lecture Number - 2

Bridge Launching Girders(Part-I, Agenda Issues related to planning and execution o LG!

Lecture Report

"ate ##nd

$ul%', )ime #*''pm to +*''pm

enue Conerence hall at st

loor e..anine, HO, um/ai

Coordinator "esign "epartment and C))O

0e% spea1er 2hri 23 B3 $oshi (Consultant, ree-lancer!

Attendees All 4ngineers rom "esign and Planning department, 2B5-, 2B5-# (total o 6' 7!

(Up) Showing Large Audience for the session

8or9ard

About two years back Afcons started an innovative activity called lassroom at sites!" #$e main aim

of t$is activity was to $ave knowledge s$aring between various team members available at t$e sites"

%oon various sites took a lead in conducting t$ese sessions& w$ic$ in turn $el'ed t$e fres$ engineers

to elevate in t$eir carreer" (nowing t$is& t$e organisation decided to start t$is activity even at )*&

formally& under title lass-+oom at )*!" ,ecause at )* suc$ activities are already taking 'lace& but

under different de'artments under different names" lass +oom at %ite +A%. and lass +oom at

)*! +A). are t$e activities w$ic$ will integrate all suc$ effort of im'arting / s$aring of knowledge"

Also t$ese activities will be $el'ful to ca'ture t$e knowledge and record / retrieve it for future use"


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Contents

0n most of t$e corridor 'roects t$e faster erection of bridge su'er structure is ac$ieved only by t$e

use of 'ro'erly 'lanned and eecuted Launc$ing 3irder L3." ,ut often t$e design of Launc$ing

3irder is given em'$asis t$at t$e issues related to Planning& 4inancing and 4abrication /ommissioning / 5ecution of L3" 0n t$e 'resent first 'art of t$e lecture t$e key s'eaker introduced

t$e attendees to all t$e intricacies involved in issues ot$er t$an t$e design" 0n t$e second 'art w$ic$

is 'lanned to be conducted s$ortly& t$e issues 'ertaining to t$e design will be covered" 0n t$e

'resent re'ort t$e to'ics covered in first 'art of t$e lecture are briefly covered"

(Up) left Mr. Karnik Introduced to Mr. S. . !oshi " (right)" Mr. S. . !oshi engrossed in the presentation

Launc$ing girder is also called as Launc$ing truss or a bridge erection gantry" ,efore starting t$e

design of t$e L3 t$e 'lanning engineer must ensure t$at $at is a Proect +e7uirement!" orrect

selection of ty'e of L3& and not ust t$e design. is key to success of t$e 'roect" #$e 'lanning

engineer s$all consider following factors in mind before a''roac$ing t$e designer for final design 8-

a. #otal duration of t$e 'roect and estimated time cycle 'er s'an"

b.

#y'e of L3 under slung / over slung9 #russ / Plate 3irder9 for segmental bridge / continuous

girder& bo girder / 0-girder etc".

c. %'lit u' of all maor minor activities / task involved in o'eration of L3" 0dentification of t$ose

activities falling on / fouling wit$ t$e critical 'at$"

d. %uitability and #y'e of bridge su'er structure to suite L3"

e. :esired so'$istication in t$e launc$ing e7ui'ment use of $ydraulics vs" a sim'le L3."

f.

Availability of eisting L3 vs Purc$ased or 4abrication L3"

g. +e7uirement of ot$er e7ui'ment ranes& etra 'ylons& cross girders& acks etc". / ot$er

facilities casting yard& barges& roads below& access from back / ground etc".

$.

Lengt$ of t$e L3 1 ; s'an& 2 s'an& 2 ; s'an& < s'an"

i. %kill sets of t$e o'erating team"

After studying all t$e above 'arameters t$e 'lanner s$all 're'are a conce't drawing s$owing

various ste's involved in erection of ty'ical s'an& if all s'ans are e7ual. and a''roac$& :esign&

5ecution and later 4inance team for t$e furt$er discussions"


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:uring t$e lecture t$e s'eaker covered case studies from various 'ast 'roect done by Afcons and

ot$er com'anies and s$ared t$e good features and even t$e mistakes t$at may $a''en"

#$e issues like negotiation of curves& negotiation of a longitudinal gradient& 'rovision for cross slo'e&

side-s$ifting of lowered girders& construction of wet-oint& staggering of t$e segments& use of$ydraulics etc" may consume considerable time" *ften t$e designer is asked to 'rovide t$e L3 wit$

so'$isticated devices to reduce t$e time cycle" ,ut t$e cost encored in suc$ devises vs" t$e time

consumed in t$eir absence s$all be c$ecked by t$e Planner in advance& before making selection of

ty'e of L3 or even before finalising t$e design"

(up) I#portance of Seg#ent staggering during $urning the seg#ent

aution in use of devices like $ydraulic acks& $eavy winc$es for lifting t$e girder& )#-,ars :ywidag

or =cAlloy.& counterweig$ts& multi'le su''orts& sus'ension carts trolleys.& c$ariots etc was

discussed in details" #$e im'act of t$ese minor 'oints could be maor at t$e work front"

(up) I#portance of Seg#ent staggering during $urning the seg#ent

Also use of s'$erical nuts& knuckle bearings at front su''ort during marc$ing o'eration of L3 etc"

was e'lained in detail" #$e issues related to construction stage analysis and $ow t$e load due to

L3 covers t$e t$e design t$an t$e traffic live load was discussed" >se of sim'le ecel s'read s$eets

to calculate t$e stability of L3 during forward and backward loads was e'lained" A'art of t$e film


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from actual eecution in one of t$e 'ast 'roects was dis'layed during t$e lecture9 also one

animation s$owing side s$ifting of t$e L3 wit$ acks was dis'layed and discussed"

(up) A t%pical Sche#e &rawing for L' operations

:uring t$e session )on" =:& %$ri" (" %ubramanian& visited t$e venue and interacted wit$ t$e training

faculty for a few minutes" )e once again em'$asised on more and more knowledge transfer t$roug$

t$e +A% and +A)"

#$e overall im'act of t$e session was very good" ,ut t$ose w$o did not $ad a 'rior e'erience in

using t$e L3 found it very e$austive knowledge" *nly after 'racticing t$e 'oints discussed one can

master t$em"

#$e net session of design as'ects of t$e L3 will be conducted s$ortly"

Learning :esources

#$e com'lete lecture in PP# format& Lecture notes and t$e @ideo recorded format is available at )*&

wit$ :esign de'artment& Library and ##*"


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(up) A t%pical Si#ple cel Spread sheet to check the Sta*ilit% of L'

(U+) Left $%pical !ack arrange#ent for forward pushing of L'"

Right $%pical cel spred sheet to check the sta*ilit% of L' while #o,ing on gradient

-#*#B ?CC #*N

N

;

2LI"4

-

4+0#0*N

4

%L0:5-N5#

DA(

4*+5

1 8 1CC C"C1 C"C1 ?CC ?"CC ?"CC C"CC E"CCC"C< ?CC ?"CC 12"CC C"CC 16"CCC"C ?CC ?"CC 2C"CC C"CC 2?"CCC"CF ?CC ?"CC 2E"CC C"CC


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(up) A t%pical arrange#ent for #o,ing L' on the -ur,ed align#ent

A/out 0e%-spea1er

%$ri" %"," Dos$i& 'ost graduate in =arine 5ngineering from N0#-%uratkal& $as more t$an 2 years of

0ndustrial 5'erience in Planning - :esigning and commissioning of various Permanent and 5nabling

orks." 0n 'ast& $e $as worked wit$ Afcons for about 1G years and t$en wit$ ) for about E years"

)e started $is career wit$ Afcons on #$ane reek +ailway ,ridge 'roect #+,. at site" )e $as

worked wit$ senior %tructural 5ngineers like Late. =r" )ans (elm in 'ast" )e was instrumental for

many landmark designs during $is career" 4or some time& $e also was $eading t$e :esign and

Planning :e't at Afcons and t$en at )." Presently $e is working as a onsultant / %'ecialist in t$e

0ndustry"

I I I

:eport prepared /%

5r" @ivek Ab$yankar

%r" =anger :esign.

)*

bridge launching girder - lecture notes

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