components of building 2.doc

7/25/2019 components of building 2.doc

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RGCER DEPT. OF CIVIL ENGG. BASICS OF CIVIL ENGINEERIN

3.COMPONENTS OF BUILDING

INTRODUCTION TO TYPES OF LOADS ON BUILDINGS:

Dead Load

Live Load/Imposed Load

Wid Load

!o"i#o$a% P"ess&"es Be%o' G"ade

S$"&($&"a% Mem)e" Fo"(es

Up%i*$

Ea"$+,&a-e

Dead Load:The dead load in a building com!i"e" #he $eigh# o% !oo%"'oo!"& beam"& column"& $all"& and a!#i#ion $all" e#c. $hich %o!me!manen# a!# o% #he building. I# i" #o be %ound b( $o!)ing ou*olume o% each a!# and #hen mul#il(ing $i#h uni# $eigh#. +ni$eigh#" o% *a!iou" ma#e!ial" a!e li"#ed in a!#,I o% IS- /0. +ni$eigh#" o% "ome o% #he common ma#e!ial" a!e !e"en#ed in Table 1 .

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Live Load/Imposed Load: The load" $hich )ee on changing %!om #ime #o#ime a!e called a" imo"ed load". Common e2amle" o% "uch load" in abuilding a!e #he $eigh# o% #he e!"on"& $eigh#" o% mo*able a!#i#iondu"# load" and $eigh# o% %u!ni#u!e". The"e load" $e!e %o!me!l( )no$na" li*e load". The"e load" a!e #o be "ui#abl( a""umed b( #he de"igne!. Ii" one o% #he ma3o! load in #he de"ign. The minimum *alue" #o bea""umed a!e gi*en in IS /0 4a!# 56718/. I# deend" uon #h

in#ended u"e o% #he building. The"e *alue" a!e !e"en#ed %o! "9ua!eme#!e o% 'oo! a!ea. The code gi*e" #he *alue" o% load" %o! #he %ollo$ingoccuanc( cla""i:ca#ion-4i6 Re"iden#ial building"7d$elling hou"e"& ho#el"& ho"#el"& boile! !oomand lan# !oom"& ga!age".4ii6 Educa#ional building"4iii6 In"#i#u#ional building"4i*6 A""embl( building"

4*6 Bu"ine"" and o;ce building"4*i6


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ho#el o! a ho"#el building #he load" "eci:ed a!e&

Wid Load:The %o!ce e2e!#ed b( #he ho!i=on#al comonen# o% $ind i" #o

be con"ide!ed in #he de"ign o% building". I# deend" uon #he *eloci#( o$ind and "hae and "i=e o% #he building. Comle#e de#ail" o% calcula#ing$ind load on "#!uc#u!e" a!e gi*en in IS,/0 4Pa!# >6 ,18/.

T.pes o* soi%s "o(-s ad *o&da$io s$"a$a:

Ro(-s ad soi%s 0 Ro(-s: B"o-e i$o "e1&%a" ad i""e1&%a" si#es ). 2oi$s 0

Soi%s 3pa"$i(&%a$e ea"$+ ma$e"ia%4:

Bo&%de" 3$oo %a"1e $o )e %i*$ed ). +ads4

(o))%e 3pa"$i(%e $+a$ (a )e %i*$ed ). a si1%e +ad4

1"ave% a11"e1a$es 3(o&"se 1"aied pa"$i(%e %a"1e" $+a 567mm4 sad

3*"i($ioa% si#e va"ies *"om 567 $o 8685mm4 si%$s 3*"i($ioa% %o' s&"*a(e0a"ea $o vo%&me "a$io si#e va"ies *"om 8685 mm $o 86889mm4 ad

(%a.s 3(o+esive 0 *ie 1"aied 0 +i1+ s&"*a(e0a"ea $o vo%&me "a$io si#e

sma%%e" $+a 86889 mm4

Pea$ 3soi%s o$ s&i$a)%e *o" *o&da$ios4

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RGCER DEPT. OF CIVIL ENGG. BASICS OF CIVIL ENGINEERINPo"o&s3sad.4 C%a.s

CONCEPT OF BEARING CAPACITY

DefnitionBea!ing caaci#( o% #he "oil mean" #he load ca!!(ing caaci#( o% #he"ub"oil. OR The o$e! o% %ounda#ion "oil #o hold #he %o!ce" %!om #he"ue!"#!uc#u!e $i#hou# unde!going "hea! %ailu!e o! e2ce""i*"e##lemen#.

Thi" *alue i" de#e!mined u"ing #he %o!mulae de*eloed in "omechanic". I# deend" uon #he cohe"i*ene""& %!ic#ional !oe!#ie" anduni# $eigh# o% "ub"oil. I# can be de#e!mined b( di!ec#l( b( a #e"# )no$na" la#e load #e"#. In #hi" #e"# a >?? @ >?? mm @ 1 mm #hic) o! 0? @0? mm @ 1 mm #hic) "#eel la#e i" )e# di!ec#l( on #he "ub"oil. A"ho!# "#eel column i" connec#ed #o i# and a# g!ound le*el a la#%o!m ibuil#. Thi" la#%o!m i" loaded $i#h an inc!emen# o% 0 )N a# a #ime and#he "e##lemen# i" ob"e!*ed #h!ough a le*el. Thi" !oce"" o% loading and


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ob"e!*ing "e##lemen# i" con#inued #ill #he "ub"oil (ield" and "udden"in)ing i" ob"e!*ed. Load "e##lemen# cu!*e i" lo##ed and loadco!!e"onding #o (ielding i" #a)en a" ul#ima#e bea!ing caaci#( o% #he"oil. Thi" *alue i" di*ided b( a %ac#o! o% "a%e#( o% 5 #o > deending uon#he !eliabili#( o% #he "oil and #he *alue #hu" ob#ained i" )no$n a" "a%e

bea!ing caaci#( 4SBC6 o% "oil.The %ollo$ing a!e a %e$ imo!#an# #e!minologie" !ela#ed #o bea!ing

caaci#( o% "oil.

1 Ultimate Bearing Capacity (q)- I# i" #he ma2imum !e""u!e #ha# a

%ounda#ion "oil can $i#h"#and $i#hou# unde!going "hea! %ailu!e.

2 Net ultimate Bearing Capacity (qn) : I# i" #he ma2imum e2#!

!e""u!e 4in addi#ion #o ini#ial o*e!bu!den !e""u!e6 #ha# a %ounda#ion

"oil can $i#h"#and $i#hou# unde!going "hea! %ailu!e. 9 n

9%, 9o

e!e& 9o!e!e"en#" #he o*e!bu!den !e""u!e a# %ounda#ion le*el and i"

e9ual #o D %o! le*el g!ound $i#hou# "u!cha!ge $he!e 9 %i" #he uni#

$eigh# o% "oil and D i" #he de#h #o %ounda#ion bo##om %!om G!ound

Le*el.

3 Sae Bearing Capacity (qs) :I# i" #he "a%e e2#!a load #he %ounda#ion

"oil i" "ub3ec#ed #o in addi#ion #o ini#ial o*e!bu!den !e""u!e.

o

n

s qF

qq +=

e!e. F !e!e"en#" #he %ac#o! o% "a%e#(.

!llo"a#le Bearing $ressure (qa) :I# i" #he ma2imum !e""u!e #h

%ounda#ion "oil i" "ub3ec#ed #o con"ide!ing bo#h "hea! %ailu!e an

"e##lemen#.

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OR

I# i" #he ma2imum allo$able ne# loading in#en"i#( $hich can be alied

#o #he "oil #a)ing in#o accoun# #he ul#ima#e bea!ing caaci#(& #he

amoun# and #he )ind o% "e##lemen# e2ec#ed and #he abili#( o% #he gi*en

"#!uc#u!e #o $i#h"#and #he "e##lemen# e2ec#ed. I# i" #he!e%o!e

deenden# uon bo#h #he "ub,"oil and #he #(e o% building !oo"ed #o

be e!ec#ed #he!eon. The allo$able bea!ing !e""u!e ado#ed in #h

de"ign o% #he %ounda#ion i" le""e! o% #he %ollo$ing #$o *alue"-

a6 The "a%e bea!ing caaci#( o% #he "oil& o!

b6 The ma2imum allo$able bea!ing !e""u!e #ha# #he "oil can #a)e

$i#hou# e2ceeding #he "eci:ed limi#" o% #he e!mi""ible

"e##lemen#.

%actors in&uencing Bearing Capacity

Bea!ing caaci#( o% "oil deend" on man( %ac#o!". The %ollo$ing a!e

"ome imo!#an# one".

1. T(e o% "oil

5. +ni# $eigh# o% "oil

>. Su!cha!ge load

. De#h o% %ounda#ion

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1?. Inclina#ion o% %oo#ing load

11. Inclina#ion o% g!ound

15. Inclina#ion o% ba"e o% %ounda#ion

1 Pla#e Load Te"#

Fig- #(ical "e# u %o! Pla#e Load #e"# a""embl(

1. I# i" a :eld #e"# %o! #he de#e!mina#ion o% bea!ing caaci#( and

"e##lemen# cha!ac#e!i"#ic" o% g!ound in :eld a# #he %ounda#ion le*el

5. The #e"# in*ol*e" !ea!ing a #e"# i# u #o #he de"i!ed %ounda#io

le*el.

>. A !igid "#eel la#e& !ound o! "9ua!e in "hae& >?? mm #o /0? mm in

"i=e& 50 mm #hic) ac#" a" model %oo#ing.

. Dial gauge"& a# lea"# 5& o% !e9ui!ed accu!ac( 4?.??5 mm6 a!e lace

on la#e on la#e a# co!ne!" #o mea"u!e #he *e!#ical de'ec#ion.

0. Loading i" !o*ided ei#he! a" g!a*i#( loading o! a" !eac#ion loading

Fo! "malle! load" g!a*i#( loading i" acce#able $he!e "and bag

al( #he load.

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. In !eac#ion loading& a !eac#ion #!u"" o! beam i" ancho!ed #o #h

g!ound. A h(d!aulic 3ac) alie" #he !eac#ion load.

/. A# e*e!( alied load& #he la#e "e##le" g!aduall(. The dial gaug

!eading" a!e !eco!ded a%#e! #he "e##lemen# !educe" #o lea"# couno% gauge 4?.??5 mm6 a*e!age "e##lemen# o% 5 o! mo!e gauge" i

!eco!ded.

. Load V" "e##lemen# g!ah i" lo##ed a" "ho$n. Load 4P6 i" lo##ed

on #he ho!i=on#al "cale and "e##lemen# 46 i" lo##ed on #he *e!#ica

"cale.

8. Red cu!*e indica#e" #he gene!al "hea! %ailu!e #he blue one

indica#e" #he local o! unching "hea! %ailu!e.

1?. The ma2imum load a# $hich #he "hea! %ailu!e occu!" gi*e

#he ul#ima#e bea!ing caaci#( o% "oil.

1. Si=e eec# i" !onounced in g!anula! "oil. Co!!ec#ion %o! "i=e eec

i" e""en#ial in "uch "oil".

5. I# i" a cumbe!"ome !ocedu!e #o ca!!( e9uimen#& al( huge load

and ca!!( ou# #e"#ing %o! "e*e!al da(" in #he #ough :eld

en*i!onmen#.

Bearing capacity o soil may #e increase' #y:

1. Inc!ea"ing #he de#h o% %ounda#ion& "ince #he lo$e! "#!a#a o

g!ound ha" na#u!al comac#ion.

5. Pu##ing g!anula! ma#e!ial" li)e "and and g!a*el on #he na#u!al "oi

and #hen comac#ing $ell.

>. B( combining #he "oil in an enclo"ed a!ea b( d!i*ing "hee# ile" o

"and ile".

. D!aining ou# #he a!ea& i% i# i" a ma!"h( land.


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0. A##em#" ha*e been made #o im!o*e bea!ing caaci#( o% "oil b(

chemical #!ea#men# al"o.

FOUNDATIONDefinition :{The low artificially built part of a structure which transmits the load of thestructure to the ground is called foundation.

ORA foundation (also called a ground sill) is a structure that transfers loads to theearth.

I# i" #ha# a!# o% #he "#!uc#u!e $hich i" in di!ec# con#ac# $i#h "oi

Founda#ion #!an"%e!" #he %o!ce" and momen#" %!om #he "ue! "#!uc#u!e#o #he "oil belo$ "uch #ha# #he "#!e""e" in "oil a!e $i#hin e!mi""ible

limi#" and i# !o*ide" "#abili#( again"# "liding and o*e!#u!ning #o #he

"ue! "#!uc#u!e. I# i" a #!an"i#ion be#$een #he "ue! "#!uc#u!e and

%ounda#ion "oil. The 3ob o% a geo#echnical enginee! i" #o en"u!e #ha

bo#h %ounda#ion and "oil belo$ a!e "a%e again"# %ailu!e and do no

e2e!ience e2ce""i*e "e##lemen#. Foo#ing and %ounda#ion a!e

"(non(mou".

!"R!O#$ O% %O"&DAT'O&:

't is often misunderstood that the foundation is proided to support the load ofthe structure. 't is in fact a deice to transmit the load of the structure to the soilbelow. %oundation is proided for the following four main purposes:

) To distribute the weight of the structure oer large area so as to aoidoer*loading of the soil beneath.

+) To load the sub*stratum eenly and thus preent une,ual settlement.

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-) To proide a leel surface for building operations.

) To ta/e the structure deep into the ground and thus increase its stability0preenting0 oerturning.

CLASSIFICATION OF FOUNDATION

S+a%%o' Fo&da$ios :

Foundations provided immediately beneath the lowest part of the structure, near to the groundlevel are known as shallow foundations. Such foundations are mostly placed on the first hardand firm strata available below the ground level.

Shallow foundations are further classified into the following types:

1. Spread footing or open trench foundations

2. Grillage foundations

. !aft foundations

". Stepped foundations

#. $nverted arch foundation

$n all these cases depth of footing is calculated using !ankine%s formula:

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&here, p ' Safe bearing capacity of soil

w ' (nit weight of soil, f ' )ngle of repose of the soil

*owever a minimum depth of +. m is provided in all cases.

;4 Sp"ead Foo$i1 Fo&da$ios :

Foundations constructed by increasing the area at the base of the structure by means of offsetsare called spread footing foundations. $n such foundations, spread is given under the base of

wall or a column by providing offsets. -his spread is known as footing and the foundation itseis called spread footing.roadly speaking, all types of shallow foundations can be referred to as spread footinfoundations. *owever ,from design and construction point of view, they have been designateseparately.-he various types of spread footing foundations are /

a4 Wa%% *oo$i1s:

-his is a common and the simplest type of spread footing foundation/ $t consists of a number ocourses of bricks, the lowest being usually twice the thickness of wall above. $n this type offoundation, the base. &idth of the wall is increased by providing #cm 0onefourth of bricklength offsets on either side of the wall. -he depth of each course is usually 1+ cm

$n some cases, however, the bottom course is made 2+cm deep. $n the case of footing for storewalls, the si3e of offset is slightly more than that of the brick wall footing.

S&i$a)i%i$.:

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This is the cheapest type of spread footing foundations and is largely used for walls of ordinarybuildings.

)4 Maso". Pi%%a" Foo$i1:Isolated footings are used to support the individual pillars and columns constructed inbrick or stone masonry. They are stepped down in the wall footing after providing 15cmoffset of foundation concrete on all the sides.

C4 Co("e$e Co%&m Foo$i1:

-hese are either stepped type, slate type or slope type, having pro4ections in the concret-o support heavy loads, reinforcement is also provided at the base. -he reinforcemen

provided is in the form of steel bars and is placed in both directions. 5oncrete columfootings may be either isolated footings or combined footings. $solated footings are useto support the individual columns, whereas combined footings are used wherpro4ections of different columns are not possible on all the sides, due to limited space.-he combined footings are generally rectangular in shape when both columns are osame sections and trape3oidal in shape when the columns are of different sections.

94 G"i%%a1e Fo&da$io :

-he foundation which consists of one or two tiers of wooden or rolled steel section with spacefilled up with concrete is known as Grillage foundation. -his is so called because the bedconstructed in this type of foundation is called grillage. -his type of construction avoids deepe6cavation and provides the necessary area at the base of the structure to reduce the intensity opressure within the safe bearing capacity of the soil.

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-he ob4ect of this type of foundation is to spread the load over a large hori3ontal area at the basof a structure.

TYPES :

7epending upon the material used in construction, grillage foundations are further classifiedinto two types.

1. Steel Grillage Foundation

2. -imber Grillage Foundation

S($-)$8$-9 :

Steel grillage foundations are useful for structures like columns, piers, stanchions sub4ected toheavy concentrated loads and hence are employed for foundations of the buildings such as

theaters, factories, town, halls etc. -imber grillage foundations re usually provided for timbercolumns sub4ected to heavy concentrated loads.-his type of grillage foundation can also be safely used for light buildings where the soilencountered is soft and is permanently waterlogged.

=4 RAFT FOUNDATION :

-he foundation consisting of a thick !.5.5 slab covering the whole area of a mat is known as rafoundation.

SUITABILITY :

-his type of foundation is useful for public buildings, office buildings, school buildings,residential uarters etc, where the ground conditions are very poor and bearing power of thesoil is so low that individual spread footing cannot be provided.

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74 STEPPED FOUNDATION :

For constructing this type of foundation, e6cavation is done into steps having short length anduniform thickness and the masonry work is done on the hori3ontal bed of concrete thusprepared.

$f there is any possibility of slipping of the structure bodily, !.5.5 piles can be driven along itsbase concrete on the sloping side.

>4 IN?ERTED ARC! FOUNDATION :

-he foundation consisting of inverted arches between the piers is known as inverted archfoundation. $n this type of foundation, the load from the piers is transferred to the soil by

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constructing arches in inverted position at their at their base. -he rise of the inverted arches isabout one ; fifth to one ; tenth of the span and they are usually build in halfbrick rings. -heposition of arches may be either along the row of piers or across the row of piers in both thedirections depending upon the nature of soil and the type of land to be taken by them.

S($-)$8$-9 :

-his of foundation is not commonly used for buildings, but it is uite suitable for otherstructures like bridges, reservoirs, tanks, supports for drainage lines etc.

DEEP FOUNDATION :

-he foundation constructed sufficiently below ground level with some artificial arrangementssuch as piles, wells etc, at their base are called deep foundations. 7eep foundation are furtherclassified into the following types /

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type of foundations is used when top soil is not capable of taking the load of the structure

even at ;" m depth.

) foundation 0 spread footing or grillage supported on piles is called a pile foundation. ) pilefoundation usually consists of a base of spread footing or grillage supported by piles at theirbottom.


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Sue! S#!uc#u!e"

4S+PER STR+CT+RE 7THPES OF CONSTR+CTION- LOAD BEARING& FRA


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alteration of rooms is possible by removing or by constructing additional walls. $n factories steframe structures are also used. $n these cases flooring is by !.5.5. and roofing is usually wittrusses supporting ).5. sheets.

-able 1.shows the comparison between !.5.5. framed structures and load bearning structures

a#le 1 Coma!i"on be#$een load bea!ing and %!amed "#!uc#u!e"

Composi$e (os$"&($io:$f facing and backing of walls are made using different materials it is called composite wa

construction. Facing material used is always good in appearance.

-he following types of composite constructions are used:1. Stone slabs facing with brick masonry backing.2. 7ressed stone facing and brick masonry backing.. rick facing with rubble stone masonry.". -ile facing and brick backing.#. rick facing and concrete backing.@. Stone facing and concrete backing.$n all these constructions proper bond between facing and backing should be achieved. For thipurpose G$ or aluminum clamps may be used. $n case of brick facing alternate courses of brick

are pro4ected inside backing. !ich plaster is used between facing and backing materials.Figure shows stone slab facing with brick masonry backing.

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components of building 2.doc