Industrial Const

8/16/2019 Industrial Const

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SEMINAR ON

INDUSTRIAL CONSTRUCTION


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INDUSTRIAL CONSTRUCTION

INTRODUCTION:

Industrial construction consist of the buildings including terrace factoriesor worsho!s" detached factories" warehouse" factor# canteens" $arets"hawer centers" s!orts halls" industrial training centers" etc%arecharacteri&ed

b# large clear o!en s!aces under light roof structures%

TYPE OF STEEL STRUCTURES

The usual for$s of roof structures are triangulated truss frames, lattice

girders and solid web portal frames and their choice de!ends considerabl#

on the e'tent of clear floor s!ace% Truss frames or lattice girders are usuall# $ore econo$ical in ter$s of

$aterial re(uired% Portal frames are chea!er to fabricate faster in construction and ha)e

ad)antages in aesthetic" ease of $aintenance and added headroo$"unobstructed b# ties or bracing $e$bers%


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Portal frames

A portal frame is distinguised !" te rigid #onne#tion of te raftersto te $osts of te frame so tat under load moments are distri!utedtroug te rafter and te $ost%

T"$es of $ortal frames:

* Reinforced concrete !ortal fra$es

* Steel !ortal fra$es

* Ti$ber !ortal fra$es


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Steel $ortal frames:

Short + $ediu$ s!an fra$es

Long s!an fra$es

Short and $ediu$ s!an fra$es the

a!e' or ridge" where the rafters

connect" is generall# $ade as an on,

site" rigid bolted connection for

con)enience in trans!orting half

!ortal fra$es %

Short,s!an !ortal fra$es $a# be fabricated off site as one fra$e% Mediu$,s!an

!ortal fra$es are generall# fabricated in two hal)es for ease of trans!ort and are

asse$bled on site with bolted connections of the rafters at the ridge" with high

strength friction gri! bolts%

Bolted conne

ction

Bolted connection

Short,s!an !ortal fra$e

Rafters & posts from same

Section of steel beam


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In long s!an steel !ortal fra$es the

!osts and lowest length of the rafters"

towards the nee" $a# often be fab

ricated fro$ cut and welded I,sections so that the !ost section and !art of the

rafter is wider at the nee than at the

base and ridge of the rafter%

Long%s$an $ortal frames

Long s!an steel !ortal fra$es ha)e

the connection of the rafters to the !osts

at the nee" haunched to $ae the

connection dee!er than the $ain raftersection for additional stiffness%

The haunched connection of the

rafters to the !osts can be fabricated

either b# welding a cut I,section to the

underside of the rafter" as illustrated in

gi)en -ig" or b# cutting and bending

the botto$ flange of the rafter and

welding in a steel gusset !late%


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The .unction of the rafters at the

ridge is often stiffened b# welding

cut I,section to the underside of the

rafters at the bolted site connection

Steel !ortal fra$es $a# be fi'ed to or !inned to bases to foundations% -orshort s!an !ortal fra$es" where thereis co$!arati)el# little s!read at thenee or haunch" a fi'ed base is oftenused% It will be seen fro$ that the steel

base !late" which is welded throughgusset !lates to the !ost of the !ortalfra$e" is set le)el on a bed of ce$entgrout on the concrete !ad foundationand is secured b# four holding,down

bolts set or cast into the concretefoundation%


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A !inned base is $ade b# sitting the

!ortal base !late on a s$all steel

!acing on to a se!arate base !late

bearing on the concrete foundation%

/ortal fra$es with a s!an of u! to 01$

are defined as short s!an" fra$es with a

s!an of 02$ to 31$ as $ediu$ s!an and

fra$es with a s!an of 32$ to 24$ as

long s!an%


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*Co$binations of slender ti$ber sections glued and nailed together" are used in

!ortal fra$es for $ediu$, and long,s!an roofs for such buildings as churches"

asse$bl# halls" s!orts halls and other single store# structures where the ti$ber

!ortal fra$es are e'!osed for a!!earance sae%

*The ad&antages of ti$ber as a structural $aterial in this for$ are its low self

weight and the co$!arati)el# little $aintenance re(uired to !reser)e and $aintainits strength and a!!earance%

*S"mmetri#al%$it# glued laminated tim!er $ortal : These !ortal fra$es are

usuall# fabricated in two sections for ease of trans!ort and are bolted together at

the ridge%These co$!arati)el# e'!ensi)e !ortal fra$es are s!aced fairl# widel# a!art to

su!!ort ti$ber or steel !urlins which can be co)ered with an# of the sheet

$aterials" slates or tiles%

TI'(ER PORTAL FRA'E


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Light weight roof covering on

225x50 timber purlins

cramp

Cavity wall

Span 14.5 m

loor slab

Shoes bolte! to concrete base

Laminations taper

"0 !eg slope20 !ia bolt

oot of portal frame insi!e cast iron shoe

*The la$inations of ti$ber

fro$ which the !ortal is

$ade are arranged to ta!er in

both the rafter and the !ostso that the de!th is greatest at

the nee" where the fra$e

tends to s!read under load"

and slender at the a!e' or

ridge and the foot of the !ost"where least section is

re(uired for strength and

rigidit#%


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EINFO CED CONC ETE PO TAL F AME

/re,cast reinforced concrete !ortal fra$es was su!!lied for the econo$ic

benefit of re!etiti)e casting in standard $oulds and close control of $i'ing"

!lacing and co$!action of concrete that is !ossible in factor# conditions%

-or con)enience in casting" trans!ort and erection on site" !re,cast concrete !ortal fra$es are generall# cast in two or $ore sections which are bolted

together on site either at the !oint of contra fle'ure in rafters or at the .unction

of !ost and rafter" or both%


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The !oint of #ontrafle)ure is that !osition along the rafters

where negati)e or u!ward bending changes to !ositi)e ordownward bending% At this !oint the $e$ber is !resu$ed to be

suffering no bending stresses so that structurall# this is the

soundest !oint to $ae a connection%

Concrete !ortal fra$es are usuall# s!aced at fro$ 4.5 to

6.0m a!art to su!!ort !re,cast reinforced concrete !urlins and

sheeting rails" cast in lengths to s!an between fra$es and

hooked or bolted to the rafters and !osts% As an alternati)e

cold,for$ed steel 5ed !urlins and sheeting rails $a# be used forthe fi'ing of !rofiled steel sheeting%


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The bases of concrete portal frames are placed in

mortices cast in concrete pad or strip foundations and

routed in position!


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#etails ot a two$bay

symmetrical pitch concrete

portal frame.

It will be seen that the

rafter, which is cast as

one unit, is bolted to the

posts at the point of

contraflexure.

A single post supports

the rafter of the frames

below the valley in the

roof and these posts

are shaped to receive

a pre-cast reinforced

concrete valley

gutter, bolted to the

rafters, which is laid

without fall to rainwater

pipes and lined with felt.


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The spacin of the internal columns belo" #alle$s ma$ be

increased b$ the use of a pre%cast concrete #alle$ beam to

support e#er$ other internal roof frame! The bul&$ #alle$ beam

"ill obstruct clear head room and add considerabl$ to the

cost of the structure! The disad#antae of this multiba$form of concrete portal frame is the number of comparati#el$

bul&$ internal columns obstructin a free "or&in area!

%he pre$cast reinforce! concretepurlins are usually of angle sectionwith stiffening ribs an! cast inlengths to span between portalframes. %he purlins are fixe! by

loops protru!ing from their en!swhich fit over an! are bolte! tostu!s cast in the rafters& with the 'oint being complete! with in$situ$cast cement an! san! mortar.


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Corrugate! fibre cement sheeting is hoo( bolte! to

the concrete purlins over an insulating lining lai!

over the purlins. )s an alternative& profile! steel

sheeting with an insulating lining may be fixe! to *e!

purlins bolte! to the portal frames. +alls may

be of soli! bric(s or concrete bloc(s fixe! between

or across the posts of the portal frames& or

fibre cement or profile! steel sheeting may be

use!.


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North Liht pre%cast reinforced concrete portal

frames construction

%he most economicalspan for this profile offrame is up to about,.0 m to minimi-e thevolume of roof space

insi!e the frames an!to avoi! the largesections of frame thatwoul! be necessaryfor greater spans.

%he south$facingslope is pitche! at220 an! the northfacing slope at 0 0to the hori-ontal.


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A pre ' cast reinforced concrete #alle$ utter ma$ be

bolted to the frames!


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) )

This is the $ost structurall#efficient and $ost co$$onl# usedt#!e of concrete !ortal fra$e% It

has been used for fa#tories*+areouses* !arns* seds and

single , store" $la#es ofasse$bl#% The slo!e of the rafters and

s!acing of !urlins and sheetingrails is usuall# arranged to suitfibre ce$ent or !rofiled steel

sheeting%

ADVANTAGES

The# could ra!idl# be trans!orted"erected and finished at an econo$iccost%

The# re(uire no $aintenance duringthe useful life of the building%

The fra$e has a so$ewhat betterresistance to colla!se during firesthan an un!rotected steel fra$e%

Due to the non,ductile nature ofconcrete of these fra$es" thead)antage of econo$# of section area

gained b# the use of the !lastic$ethod of design in the design ofsteel fra$es is considerabl# less withreinforced concrete%


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Structural steel are !ivi!e! into two main groups accor!ing to the manufacture

process/

1ot rolle! sections

2%hose obtaine! by col! rolling.

%he former comprise of the heavier sections.

Steel components are use! in 5 ways/

1)s beams an! lintels for members which suffer ben!ing stresses.

2)s columns which resist compression an! ben!ing stresses.

")s ties where the stresses are tensile

4n roof trusses an! lattice gir!ers where the forces are compressive an! tensile&

an!5or reinforcement in reinforce! concrete.

Steel framework consists of beams& channels& angles& etc. %he

fastenings between the !ifferent parts of a frame is by means of bolts& rivets an!

wel!ing

Steel structures


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North light truss and lattice gi

Up to the latter part of the nineteenth century themajority of single-storey buildings were of traditionalconstruction with timber, brick or stone walls supportingtimber-framed roofs covered with slate or tile. Thelimited spans, practicable with timber roofs, constrainedthe rapid expansion of manufacturing activitythat was occurring during the nineteenth century tomeet the demands of the rapidly increasing populationOf ngland and the very considerable export of !nished goods.

Industrial construction consist of the buil!ings

inclu!ing terrace factories or wor(shops& !etache!factories& warehouse& factory canteens& mar(ets&

haw(er centers& sports halls& in!ustrial training

centers& etc.

%hese are characteri-e! by large clear open

spaces un!er light roof structures


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latticea reular eometric arranement of

points or ob*ects

an inter"o#en open%mesh frame made

b$ crisscrossin strips of "ood+ metal+

or plastic to form a pattern

,Lattice, is used in the sense of an

open rid or mesh of slender members

fi-ed across or bet"een each other+

enerall$ in some reular pattern

of cross%diaonals or as a rectilinear

rid!

lattice girders


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The advantage of thissimple, single-storey,single bay frame iseconomy in the use of

materials by the use ofsmall section angle, tubularor "at standard mildsteel sections for thetrusses that can beeconomically fabricated and

#uickly erected.The disadvantages are3 very considerable volume of roofspace inside the triangular roofframes cannot be used for anypurpose other than housing

services such as lighting andheating,

3$here the activity enclosed by thebuilding re#uires heating, the roofspace has to be wastefully heated

as well as the useful space below.


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% disadvantage of themulti-bayvalley beam form ofconstructionis that there is very limited

depth alongside the valley beamfor the fall &slope' of rainwaterpipesfrom valley gutter outlets to

rainwater down pipes !xedtointernal columns. Theshallowfall rain water pipes thatare run

alongside valley beams will


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$ith increase in the spanof a triangular roof trussthe volume of unusedroof space and the roofframingincreases and it is,therefore, of advantageto combineseveral bays of the shedframe construction to

providecover with the leastvolume of roof space androof framing.

To minimi(e the number of internal columnsthat would otherwise obstruct the "oor, the )umbrella)or cantilever roof was adopted. *attice girders constructedat mid span in each bay support the trusses andwidely spaced internal columns in turn support thelattice girders to provide maximum unobstructed "oorspace


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The lattice girdersupportshalf of each truss witheach half cantilevered

each sideof the truss, hence thename )cantilever truss)roof. The outline insection of the columnand the truss

cantileveredeach side of the latticegirder resembles anumbrella, hence thename )umbrella) roof.


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To avoid sun glare andoverheating in summer the north lightroof pro!le was introduced, a lightsection steel roof truss asymmetrical inpro!le with the steeply sloping roof fullygla(ed and facing north.

disadvantage-

+orth light steel lattice trussconstructionoof lights in the slopes ofsymmetrical pitch roofs, whichare generally set in east and westfacing slopes, may causediscomfort through overheating insummer and disrupt

manufacturing activities by theglare from sunlight. To avoidthese possibilities the north lightroof is used. The north light roofhas an asymmetrical pro!le withthe south facing slope at / or

more to hori(ontal and the northfacing slope at from 01/ to

construction

North light truss


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2ecause of the steep pitch ofthe north facing slope thespace inside the roof trussesof a north light roof is

considerably greater thanthat of a symmetrical pitchroof of the same span. Tolimitthe volume of roof space thatcannot be used and has to

be wastefully heated, mostnorth light roofs are limitedto spans of up to about1.1m

'saw-tooth' roof


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'saw-tooth' roof


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Joinery detailstruss member


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Industrial Const

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