Posted 03 October 2012 - 09:26 AM
Respected Members, what is the main purpose o propert! modi"ers in de"nin# arme sections in etabs and how we can re$ate them to theoretica$ %now$ed#e&& Experience ser'es not on$! to confrm theor!, but di(ers rom it without disturbin# it, it Experience ser'es $eads to new truths which truths which theor! on$! has not been ab$e to reach) - *a$embert •
+2
Report
Rana aseem Moderator
•
•
Moderators
• •
22 posts
.ocationRi!adh /ni'ersit!:/ mp$o!er:Omrania 4 Associates Posted 05 October 2012 - 05:16 AM •
•
•
Propert! modi"ers in etabs are used to mode$ crac%ed beha'iour o concrete sections) he! are on$! app$ied to concrete members because o crac%in#) ross moment o inertia is bd73812 or a rectan#u$ar section, but when !ou ma%e this member o concrete, it wi$$ eperience crac%in# when $oaded ater some time) his crac%in# wi$$ happen when concrete reaches its tensi$e capacit! which is about -10; o its compressi'e stren#th)
) moment o inertia is reduced, its sti(ness is reduced, ta%in# $ess moment, and its de?ection increases because o $ess sti(ness) his moment which which the crac%e crac%ed d beam is not ta%in# ta%in# an!more an!more wi$$ be be re distributed to other structura$ members based on their sti(ness) > !ou read A=> chapter 10, there are man! sets o modi"ers used or di(erent t!pes o ana$!sis)
o% im $ea'in# rom o@ce, i !ou ha'e more doubts i wi$$ write in $ater) /mar Ma%humi, ba, waBar sa$eem and 1 other $i%e this
•
On$ine AC courses at ostruc)com Report
•
+3
/mar Ma%humi Ad'ance Member
•
Administrators
•
• •
D3 posts .ocation=anada /ni'ersit!:/, / o A mp$o!er:
• • •
Posted 05 October 2012 - 0D:05 AM
he use o these propert! modi"ers coe@cients shou$d be or ser'iceabi$it!) /pdate: Members shou$d be chec%ed or stren#th chec%s a$so usin# crac%ed section properties) Edited by Umar Makhzumi, 12 November 201 ! 12"1# $M% /pdated Answer •
waBar sa$eem, Rana aseem and Muhammad >mran Eaar $i%e this
Fhe technica$ man must not be $ost in his own techno$o#!) Ge must be ab$e to appreciate $ieH and $ie is art, drama, music, and most important$!, peop$e)I
+5
Report
Rana aseem Moderator
•
•
Moderators
• •
22 posts
.ocationRi!adh /ni'ersit!:/ mp$o!er:Omrania 4 Associates Posted 0 October 2012 - 0:0 AM •
•
•
&Umar Makhzumi&, on 0 'ct 2012 ! (") $M, said" he use o these propert! modi"ers coe@cients is or ser'iceabi$it! chec%s on$!, not or stren#th chec%s)
p$ease ep$ain more as i here im a $itt$e conused about !our statement) On$ine AC courses at ostruc)com Report
•
+
/mar Ma%humi Ad'ance Member
•
Administrators
•
• •
D3 posts .ocation=anada /ni'ersit!:/, / o A mp$o!er:
• • •
Posted 0 October 2012 - 10:12 AM &*ana +aseem&, on 0# 'ct 2012 ! ("20 $M, said" p$ease ep$ain more as i here im a $itt$e conused about !our statement)
*e?ections are a(ected, not the reinorcement) !ou can chec% that manua$$!) Fhe technica$ man must not be $ost in his own techno$o#!) Ge must be ab$e to appreciate $ieH and $ie is art, drama, music, and most important$!, peop$e)I
+6
Report
Rana aseem Moderator
•
•
Moderators
• •
22 posts
.ocationRi!adh /ni'ersit!:/ mp$o!er:Omrania 4 Associates Posted 0 October 2012 - 02:13 PM •
•
•
&Umar Makhzumi&, on 0# 'ct 2012 ! 10"2 $M, said" *e?ections are a(ected, not the reinorcement) !ou can chec% that manua$$!)
+-. M'/E* M'*E NE*-34 M'*E -NE ' M'*E M'MEN-
Attached
•
On$ine AC courses at ostruc)com •
+
Report
Rana aseem Moderator
•
•
Moderators
• •
22 posts
.ocationRi!adh /ni'ersit!:/ mp$o!er:Omrania 4 Associates Posted 0 October 2012 - 02:16 PM •
•
•
WI THOUTMODI FI ERSLESSMOMENTL ESSSTI FF NESS
Attached
•
On$ine AC courses at ostruc)com •
+D
Report
Rana aseem Moderator
•
Moderators
•
•
22 posts
•
.ocationRi!adh /ni'ersit!:/ mp$o!er:Omrania 4 Associates Posted 0 October 2012 - 02:20 PM •
•
•
o Kust compare the two ima#es, mode$ ha'in# modi"ers ha'e $ess sti(ness, so ta%e $ess moment, that moment is distributed to other sti( e$ements) so the point is i !ou reduce the sti(ness as in case o crac%in#, it wi$$ a(ect de?ection as we$$ as moments) so the reinorcement 'a$ues depend upon the moment) > a#ree with !ou that in beam desi#n ormu$a, it depends upon b and d) ow this b and d are not with modi"ers rather u$$ 'a$ues) Cut the moment which has to be used in this ormua$ is $ess because o $ess sti(ness due to reduction in modi"ers) On$ine AC courses at ostruc)com •
+9
Report
Rana aseem Moderator
•
•
Moderators
• •
22 posts
.ocationRi!adh /ni'ersit!:/ mp$o!er:Omrania 4 Associates Posted 0 October 2012 - 02:23 PM •
•
•
another thin#) i !ou put the same modi"ers or e'er! thin# $i%e wa$$s, co$umns, beams, ?oor etc))so the reduction wi$$ be uniorm it wi$$ not a(ect the resu$ts) but i !ou ma%e somethin# sti(er and another $ess sti(er so !ou basica$$! are creatin# di(erences in sti(ness so is the di(erence in the moment that wi$$ #oto these e$ements) $i%e in this eamp$e i ha'e app$ied beams L 0)3,0)3,0)3 K,m22,m33N co$s L 0),0) m11,m22N s$ab L 0)2,0)2,0)2 m11,m12,m22N wa$$s L 0),0)m11,m22N On$ine AC courses at ostruc)com
•
+10
Report
ba Moderator
•
•
Moderators
• •
1D5 posts
.ocationRawa$pindi /ni'ersit!:/, Po$itecnico *i torino Posted 06 October 2012 - 12:3 AM •
•
/mar is ri#ht) /se section modi"ers or ser'iceabi$it! chec%s) ;uote beams L 0)3,0)3,0)3 K,m22,m33N co$s L 0),0) m11,m22N s$ab L 0)2,0)2,0)2 m11,m12,m22N wa$$s L 0),0)m11,m22N
his set o modi"ers are mentioned in section 10)11)1 o 0 addition which is dedicated to computation o $atera$ de?ections o rame) Remember that code speci"cations are based on worst case scenario, and these 'a$ues are worst case scenario or $atera$ de?ections o rame)
+11
Rana aseem
•
/mar Ma%humi and asadishaB $i%e this
•
Report
Moderator
•
•
Moderators
• •
22 posts
.ocationRi!adh /ni'ersit!:/ mp$o!er:Omrania 4 Associates Posted 06 October 2012 - 0:55 AM •
•
•
> %now in the code these modi"ers are or $atera$ de?ection) but then how wou$d !ou Kusti! the reduced moment o inertia ater crac%in#& Are !ou ta$%in# about membrane s$ab which has no out o p$ane sti(ness& eah in membrane the mod"ers wi$$ not a(ect but in she$$ i !ou dont app$! the modiers, the s$ab wi$$ carr! a$$ the moment) > Kust want to be more c$ear about the concept, because we app$! mod"ers in e'er! mode$) and accordin# to A=> we can use the same modi"ers set or $atera$ and or stren#th desi#n) or wind ser'iceabi$it! the modi"ers are mu$tip$ied b! 1)5 in a separate mode$N) On$ine AC courses at ostruc)com •
+12
Report
ba Moderator
•
•
Moderators
• •
1D5 posts
.ocationRawa$pindi /ni'ersit!:/, Po$itecnico *i torino Posted 06 October 2012 - 06:02 AM •
•
hat !ou do is accordin# to code) here is nothin# wron# about it) •
Rana aseem $i%es this
•
Report
+13
/mar Ma%humi Ad'ance Member
•
Administrators
•
• •
D3 posts .ocation=anada /ni'ersit!:/, / o A mp$o!er:
• • •
Posted 06 October 2012 - 10:26 AM &*ana +aseem&, on 0: 'ct 2012 ! :"1 $M, said" > %now in the code these modi"ers are or $atera$ de?ection) but then how wou$d !ou Kusti! the reduced moment o inertia ater crac%in#& Are !ou ta$%in# about membrane s$ab which has no out o p$ane sti(ness& eah in membrane the mod"ers wi$$ not a(ect but in she$$ i !ou dont app$! the modiers, the s$ab wi$$ carr! a$$ the moment) > Kust want to be more c$ear about the concept, because we app$! mod"ers in e'er! mode$) and accordin# to A=> we can use the same modi"ers set or $atera$ and or stren#th desi#n) or wind ser'iceabi$it! the modi"ers are mu$tip$ied b! 1)5 in a separate mode$N)
> thin%, considerin# .R<* $oad actors pro'ides enou#h actor o saet!) peci"ca$$! !ou can ne'er Kusti! reduced moment o inertia ater crac%in# and no one %nows how rea$ the eact crac%in# wou$d be, what wou$d be its etent and how di(erent the $oad distribution wou$d be ater that) •
waBar sa$eem and ustian31 $i%e this
Fhe technica$ man must not be $ost in his own techno$o#!) Ge must be ab$e to appreciate $ieH and $ie is art, drama, music, and most important$!, peop$e)I
+15
Report
waBar sa$eem Ad'ance Member
•
•
Moderators
• •
39 posts
.ocationRawa$pindi /ni'ersit!:=,wah cantaQiated with / tai$aN,/ mp$o!er:CAGR>A O, RAA.P>*> Posted 06 October 2012 - 10:39 AM •
•
•
RAA when we sa! that uncrac%ed section has more inertia and more sti(ness and more moment ta%in# but crac%ed section has $ess inertia and $ess sti(ness and $ess moment ta%in#,inertia is the #eometric propert! moment ta%in# is re$ated to stren#th, uncrac%ed concrete section has $ess stren#th than crac%ed section so sir Rana what do !ou sa! about that&a$so in case o concrete when section is crac%ed it means it has started ta%in# $oads otherwise its stren#th is not u$$! #enerated so what about the sti(ness o crac%ed and uncrac%ed section& Experience ser'es not on$! to confrm theor!, but di(ers rom it without disturbin# it, it $eads to new truths which theor! on$! has not been ab$e to reach) - *a$embert •
+1
Report
waBar sa$eem Ad'ance Member
•
•
Moderators
• •
39 posts
.ocationRawa$pindi /ni'ersit!:=,wah cantaQiated with / tai$aN,/ mp$o!er:CAGR>A O, RAA.P>*> Posted 06 October 2012 - 10:51 AM •
•
•
p$ease di(erentiate she$$ and membrane &how do we sa! that one s$ab is membrane and other is she$$ or p$ate & Experience ser'es not on$! to confrm theor!, but di(ers rom it without disturbin# it, it $eads to new truths which theor! on$! has not been ab$e to reach) - *a$embert •
+16
Report
/mar Ma%humi Ad'ance Member
•
Administrators
•
• •
D3 posts .ocation=anada /ni'ersit!:/, / o A mp$o!er:
• • •
Posted 06 October 2012 - 10:5 AM &wa
or simp$icit!, remember this i it has out o p$ane sti(ness its she$$, i not its membrane) •
waBar sa$eem $i%es this
Fhe technica$ man must not be $ost in his own techno$o#!) Ge must be ab$e to appreciate $ieH and $ie is art, drama, music, and most important$!, peop$e)I
+1
Report
ba Moderator
•
•
Moderators
• •
1D5 posts
.ocationRawa$pindi /ni'ersit!:/, Po$itecnico *i torino Posted 06 October 2012 - 10: AM •
•
&wa
membrane is capab$e o ta%in# tensi$e stresses on$! $i%e our s%in or tarpa$ urdu wordN) ord s$ab used in structura$ en#ineerin# cant be membrane) sha$$ is capab$e o ta%in# shear and moment) An! thin# that can ta%e shear or moment can a$so ta%e direct tension or compression) p$ate is she$$8s$ab $oaded in its p$ane $i%e shear wa$$) •
waBar sa$eem, Rana aseem and haro0n $i%e this
•
Report
+1D
ba Moderator
•
•
Moderators
• •
1D5 posts
.ocationRawa$pindi /ni'ersit!:/, Po$itecnico *i torino Posted 06 October 2012 - 11:01 AM •
•
&wa $M, said" RAA when we sa! that uncrac%ed section has more inertia and more sti(ness and more moment ta%in# but crac%ed section has $ess inertia and $ess sti(ness and $ess moment ta%in#,inertia is the #eometric propert! moment ta%in# is re$ated to stren#th, uncrac%ed concrete section has $ess stren#th than crac%ed section so sir Rana what do !ou sa! about that&a$so in case o concrete when section is crac%ed it means it has started ta%in# $oads otherwise its stren#th is not u$$! #enerated so what about the sti(ness o crac%ed and uncrac%ed section&
?eura$ sti(ness o section is abi$it! to attract moments) so crac%ed section wi$$ attract $esser moment as on$! part o section is a'ai$ab$e to resist rotation) *o not conuse moment attractin# abi$it! sti(nessN o section with its stren#th) ection with $esser sti(ness can ha'e #reater stren#th as it depends upon materia$ stren#ths, reinorcement and sie and shape crossection)
+19
•
/mar Ma%humi, ustian31 and Rana aseem $i%e this
•
Report
/mar Ma%humi Ad'ance Member
•
Administrators
•
• •
• • •
D3 posts .ocation=anada /ni'ersit!:/, / o A mp$o!er:
Posted 06 October 2012 - 11:09 AM ;uote RAA when we sa! that uncrac%ed section has more inertia and more sti(ness and more moment ta%in# but crac%ed section has $ess inertia and $ess sti(ness and $ess moment ta%in#,inertia is the #eometric propert! moment ta%in# is re$ated to stren#th, uncrac%ed concrete section has $ess stren#th than crac%ed section so sir Rana what do !ou sa! about that&a$so in case o concrete when section is crac%ed it means it has started ta%in# $oads otherwise its stren#th is not u$$! #enerated so what about the sti(ness o crac%ed and uncrac%ed section& ;uote ?eura$ sti(ness o section is abi$it! to attract moments) so crac%ed section wi$$ attract $esser moment as on$! part o section is a'ai$ab$e to resist rotation) *o not conuse moment attractin# abi$it! sti(nessN o section with its stren#th) ection with $esser sti(ness can ha'e #reater stren#th as it depends upon materia$ stren#ths, reinorcement and sie and shape crossection)
o sum it here, desi#n !our members or au#mented $oadswith $oad actorsN and chec% them or ser'iceabi$it! with crac%ed section)) its a conser'ati'e wa!, super conser'ati'e to #et #ood desi#n) A$$ members are #ood, e'en i the! crac% and meet ser'iceabi$it! reBuirements which ma! be di(erent upon their intended useN) /pdate: Members shou$d a$so be chec%ed or stren#th usin# crac%ed sections) >ts more sae to app$! to both ser'iceabi$it! and stren#th conditions) ba and ustian31 $i%e this
•
Fhe technica$ man must not be $ost in his own techno$o#!) Ge must be ab$e to appreciate $ieH and $ie is art, drama, music, and most important$!, peop$e)I
•
+20
/mar Ma%humi Ad'ance Member
•
Administrators
•
• •
• • •
D3 posts .ocation=anada /ni'ersit!:/, / o A mp$o!er:
Posted 06 October 2012 - 11:25 AM &baz&, on 0: 'ct 2012 ! 11"2# $M, said" membrane is capab$e o ta%in# tensi$e stresses on$! $i%e our s%in or tarpa$ urdu wordN) ord s$ab used in structura$ en#ineerin# cant be membrane)
sha$$ is capab$e o ta%in# shear and moment) An! thin# that can ta%e shear or moment can a$so ta%e direct tension or compression) p$ate is she$$8s$ab $oaded in its p$ane $i%e shear wa$$)
here is an ecerpt rom on o m! a' boo%s on structura$ desi#n, > read it some 3 !ears bac%, and it a$wa!s reminds me how we structura$ en#ineers can ep$oit materia$ properties to achie'e robust desi#ns)
;uote Cecause concrete is easi$! ormed and shaped, its compression stren#th ma%es it the idea$ materia$ or she$$s o an! nature) he wor% o
ba, waBar sa$eem, Rana aseem and 2 others $i%e this
Fhe technica$ man must not be $ost in his own techno$o#!) Ge must be ab$e to appreciate $ieH and $ie is art, drama, music, and most important$!, peop$e)I
Report $a6e 1 o? 2
•
•
NE@-
Cac% to otware >ssues •
• •
•
1
•
2
•
•
A$so ta##ed with one or more o these %e!words: Propert! modi"ers, etabs
Civil/ Structural Engineering → Concrete Design →
Conflict In Analysis And Design Results Started by abdul qadeer 06 , !ay "0#
$attern %ive %oad, Etabs
&eneral → Students 'one →
Suggest So(e Institute )or %earning Civil Engineering Soft*are In Isla(abad +r Else -ere. Started by Syed abbar S-a- , 0 A1r "0#
Soft*are, Isla(abad, Etabs, Safe
Civil/ Structural Engineering → Soft*are Issues →
$roble( In Etabs Design Su((ary Started by 2-alid , 3 an "0#
Etabs, Design Su((ary and (ore444
Civil/ Structural Engineering → Soft*are Issues →
$ro1erty !odifiers )or Retaining alls Started by asadis-aq , 0" an "0#
$ro1erty !odifiers and (ore444
Civil/ Structural Engineering → Concrete Design →
)e* 5uestions4 $lease eed 7rgent 8el14 Started by igger , 09 Dec "0:
safe, etabs, colu(ns, bea(s
0 users4 are readin6 this topic 0 members, 0 #uests, 0 anon!mous users 1) 2) 3) 5)
tructura$ n#ineerin#
=i'i$8 tructura$ n#ineerin#
otware >ssues Pri'ac! Po$ic!
→
•
•
=han#e heme
•
Ge$p =ommunit! P)Coard .icensed to: tructura$ n#ineerin# PC %in C! SirteB
