Different Parts of Steel Bridges

7/25/2019 Different Parts of Steel Bridges

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Training Programme on Steel/Composite Bridge Venue : Dehradun, UTTARAKHAD

TIME! "#$%% ! "&$'% PRESENTER! Reepa() Kallot) A*hi+it hosh

TOPICS ! Di--erent parts/.omponents/steel Composite Bridges

DIFFERENT PARTS/COMPONENTS/STEEL & COMPOSITE BRIDGES

Earlier, for the second set of this campaign at Uttaranchal, a 110m long Truss and its

alternatives of a Flat Arch 110m from springing point to Springing point and a

continuous plate Girder/! dec" composite structure of spans #0m $0m #0m%&

110m' (ere chosen for hands on e)ercise*

As, three A# si+e dra(ing have een made, a descriptive itemi+ation of the

components ma- e useful*

%1' THE TRUSS %.roportions in Second set' the truss is meant to e a modied

(arren Truss, (hich is good loo"ing as (ell as ecient*

The Truss (ill have these follo(ing components

1%1' Bottom Chord (Tenson! (ith ma)imum section si+e in the middle, as theretension (ill e most severe*

1%2' To" Chord (Com"resson! (ith ma)imum Section si+e at the middle, (herethere (ould e ma)imum compression*

This memer, cannot uc"le, up(ards or do(n(ards, ecause of 3iagonals and

4erticals, (hich are called 5Shear 6emers7 or 58e 6emers7 ut it can uc"le sd

(a-s*

Therefore it should e restrained - 5.lan 9earings7 provided at the centre of the Top

chords, connected - a 5Triangulated7 frame(or" to oth the chods*

1%#' The #e$ Mem$ers e*g* the 3iagonals and the 4erticals

The rst 3iagonal is over the 9earing and is su:ected to ver- severe compression* ;tis called 5a"er7*

The Second 6emer is a 54ertical7 (hich - virtue of its ero Force ut it is used to support T(o !ross

girders and thus reduces the local ending stress in the ottom chord*

The third memer is a 3iagonal (hich is in Tension eing connected (ith the5a"er7 at the Top*

As these are 5Shear 6emers7? the forces (ill e progressivel- less, as the memersapproach the centre of the span*

& 3A@1 & %;TE6#0 %1B*00 1$*#0' DIFFERENT PARTS/COMPONENTS/STEEL & COMPOSITE

BRIDGES .age %of


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So, these are three t-pes of 58e7 memers namel-, The !ompression 3iagonals,

including the a"er, the Tension 3iagonals and the 4erticals, (hich are perpendicular

to the ottom chord*

1%B' PLAN BEARINGS AT OF TOP CHORD*

These memers are supposed to give lateral stailit- to the Top chords, (hich can

uc"le side(a-s* The forces for (hich these memers are to e designed, are 2CD

of the local compressive force, in the Top chord*

1%$' Cross Grders ' Com"oste Setons (hich are connected to the dec" sla -

5Shear !onnectors7 and are called 5adder t-pe Floor 3uc" Supports7

8ith an overhang at oth sides, the- constitute the carriage (a- for vehicles and

foot(a-s at sides*

These in a nutshell, are the $ t-pes of main memers, (hich can e anal-sed as a

5SPACE FRAME) if desired and the memer si+e assumptions :ustied - an-

modern code, such as 9S $B00 .arts #, B %for design' and $, 9earings, Splices, 8e

6emer to chord girder connections, !! autments etc* are e)tra*

*+,THE FLAT ARCHAn 5open 8e7 truss conguration aleit lighter than a s-stem of plate

girder or one single o) girder, (ill e still fairl- heav-*

The alternative is at Arch (hich (ould e much lighter*ere the components are

1* The Arch i2* The Spandrel !olumns#* The side girders continuousB* The cross girders (hich (ould e composite*$*%+ THE ARCH RIBS -.

The arch ris are usuall- made up of uilt up ; section to ease connections to

spandrel columns* 6odern concepts use !S or SS ut here oth the connections

and the resulting :oint designs are comple) and lends to good Hualit- site (elding

onl-* 9lind olts etc* for connecting tue to tue are not availale in ;ndia -et*

Therefore the Arch is interconnected (ith 5;n .lane Triangulated 9racings7 (ill eof uilt up TS section*


BRIDGES .age *of


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A T(o .in or rather a )ed ase such i, happens to e of variale section depth

and su:ected to comined 9ending and !ompression the compressive forces eing

dominant*

The Thurst goes in the foundation oc" and chances of slip circle failures (ill easent*

Splices can e (elded ectangular End plate t-pe (hich is ecient for a

compressive memer ut ma- e considered ugl-* All connections should e made

of SFG olts*

%+ THE SPANDREL COLUMNS-.The Spandrel columns ehave li"e the verticals of a erendee0 Frame and should e

having moment connections (ith oth the Edge Girder and the Arch i*

The Spandrel columns too should e of uilt up or olled parallel ange ; sections

(ith olted ase plate on the arch i and olted !ap .late under the Edge girder*Spandrel columns should e raced together in the transverse direction, so as to

distriute EarthHua"e* The column tops should e raced in plan*

*+ THE EDGE GIRDER-.The Edge Girder or Side Girders too should e of uilt up ; section and continuous

over the Spandrel column*

The Edge Girder (ill e e)pected to go e-ond the Springing points of the Arch

ending up on, sa-, 53(arf Autments7

The length of the overhand depends on the slope of the Gorge side*

1+ THE CROSS GIRDERS -.The !ross Girders are e)pected to e composite and thus made up of anges of un

eHual (idths* Top Flange (ill narro(er and 9ottom Flange (ill e (ider*

i"e the concept in the Truss, the 5adder7 T-pe cross Girder (ould have overhangs,

(hich (ould doule up as footpaths, as (ell as for carriage of services*

The !ross Girders are to e laterall- supported at the 5(et concrete7 stage

to prevent lateral torsional uc"ling of the top ange (hich (ould e in

compression*

(1!CONTINUOUS COMPOSITE HTS (Gr 2,! PLATE GIRDERS RC DEC3+ GR+FCU 124 PARAPET5 UPSTAND GR FCU ,+

!I6.IJEJTS IF #0, $0, #0 & 110, TITA EJGTS B G;3E 9;3GE*


BRIDGES .age 1of


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For a t-pical plate Girder/! dec" continuous composite, the principal components(ould e as follo(s

1' 6ain plate girders much e of Even Jumer e*g* 2, B, K or L*1*1 Span Sections1*2 .ier Sections

1' ;ntermediate !ross 9racings et(een pairs of girder for ensuing lateral stailit-to compression anges*

2' !ross 9racings over .iers continuous to laterall- support compression ange atottom and also to share, Transvene hori+ontal loads %EarthHua"e, (ind, impact etc*'

#' 8e stiMeners vertical at Span*

B' 8e stiMener ori+ontal at .iers*

$' 8e stiMener ori+ontal at .iers*

K' 9earing stiMeners

N' Oac"ing stiMeners

L' Splices

Documents

Different Parts of Steel Bridges