Staad Pro Warnings

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Warnings in output of Staad Pro Warnings in output of Staad Pro

Two warnings : Two warnings :

1.

1. InInststababiililityty 2.

2. ZeZero ro StStififfnfnesess.s.

1.0 Instability Warnings 1.0 Instability Warnings:: Truss member:

Truss member: Defining

Defining a a member member as as a a TRUSS TRUSS member member when when it it needs needs to to carry carry Shear Shear and and oment.oment. !e.g" In the truss #oint$ %ertical member will transmit shear forces to the hori&ontal

!e.g" In the truss #oint$ %ertical member will transmit shear forces to the hori&ontal members. If the members are s'ecified as TRUSS elements$ then they cannot carry members. If the members are s'ecified as TRUSS elements$ then they cannot carry shear forces and hence will re'ort instability as the load from the %ertical members shear forces and hence will re'ort instability as the load from the %ertical members cannot go through the hori&ontal members.

cannot go through the hori&ontal members. To

To eliminate eliminate this this 'roblem$ 'roblem$ instead instead of of s'ecifying s'ecifying TRUSS TRUSS elements$ elements$ you you s'ecify s'ecify themthem as a member with 'artial moment release o'tion. Use member Release s'ecification as a member with 'artial moment release o'tion. Use member Release s'ecification with 'artial

with 'artial release of release of (.)) instead (.)) instead of TRUSS of TRUSS s'ecification.s'ecification. Im'ro'er Su''orts:

Im'ro'er Su''orts: *or

*or e+am'le e+am'le in in a a single single storey storey bay bay ,ortal ,ortal frame$ frame$ if if both both the the su''orts su''orts are are rollers$rollers$ then the frame is instable and hence you will get instability message. -ou must mae then the frame is instable and hence you will get instability message. -ou must mae one su''ort to be 'inned.

one su''ort to be 'inned. Stiffness:

Stiffness:

/onnecting

/onnecting %ery %ery stiff stiff member member with with a a %ery %ery wea wea member member will will gi%e gi%e instability. instability. This This isis due to large %ariation in stiffness of ad#acent members which maes the matri+

due to large %ariation in stiffness of ad#acent members which maes the matri+ in%ersion to re'ort instability. -ou need to ad#ust the I for both the members to in%ersion to re'ort instability. -ou need to ad#ust the I for both the members to eliminate this error.

eliminate this error. Du'lication:

Du'lication: Du'lication

Du'lication nodes nodes at at #oint$ #oint$ o%erla''ing o%erla''ing elements$ elements$ ,lates ,lates will will lead lead to to instability. instability. -ou-ou need to go to Tools

need to go to Tools  /hec facilities to detect and eliminate these issues. /hec facilities to detect and eliminate these issues. There

There are are two two checs checs that that you you can can do do to to %erify %erify the the correctness correctness of of results results withwith instability messages.

instability messages. *irst

*irst you you can can study study the the static static chec chec results. results. The The a''lied a''lied loading loading and and su''ortsu''ort reactions should cancel each other for e0uilibrium. If not$ there is some 'roblemms in reactions should cancel each other for e0uilibrium. If not$ there is some 'roblemms in the model.

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Second

Second is is the the #oint #oint dis'lacement dis'lacement chec. chec. If If you you notice notice e+cessi%e e+cessi%e dis'lacement dis'lacement at at aa node there may be instability at that node. -ou can %iew the instability in 'ost

node there may be instability at that node. -ou can %iew the instability in 'ost

'rocessing mode. o to odes tab in ,ost 'rocessing and you will see the instability 'rocessing mode. o to odes tab in ,ost 'rocessing and you will see the instability sub tab if there is instability in the mode. /lic this sub tab to %iew the details in table. sub tab if there is instability in the mode. /lic this sub tab to %iew the details in table.

2.(

2.( Zero Stiffness Zero Stiffness:: The

The warning wwarning will a''ear ill a''ear when when you ha%e you ha%e a stra structure ucture in which in which there there is no is no stiffnessstiffness in a 'articular degree

in a 'articular degree of freedom. 3hile of freedom. 3hile assembling assembling global stiffness matri+ if theglobal stiffness matri+ if the stiffness in an acti%e degree of freedom is &ero$ then the structure is considered stiffness in an acti%e degree of freedom is &ero$ then the structure is considered unable to resist load acting along that degree of freedom. This is re'orted as &ero unable to resist load acting along that degree of freedom. This is re'orted as &ero stiffness messages. This message can be used to in%estigate the cause of instability stiffness messages. This message can be used to in%estigate the cause of instability of the model. The &ero stiffness messages can indicate whether any of the degree of of the model. The &ero stiffness messages can indicate whether any of the degree of freedom obstructs the load transmission to the su''orts.

freedom obstructs the load transmission to the su''orts. Zero

Zero stiffness stiffness can can ha''en ha''en in in many many situations. situations. *or *or !e.g" !e.g" a a frame frame with with trusstruss members meeting at a #oint a shear and moment and hence no relational stiffness members meeting at a #oint a shear and moment and hence no relational stiffness offered at the #oint. This will gi%e &ero stiffness warning.

offered at the #oint. This will gi%e &ero stiffness warning. 3e

3e can can use use ember ember Reease Reease o'tion o'tion instead instead of of truss truss o'tions.o'tions. 4nother

4nother !e.g" !e.g" a a 'ost 'ost held held by by cables cables which which are are 'inned 'inned at at their their base base will will getget warnings for rotational degree of freedom at the cable su''orts. 3e ha%e to use warnings for rotational degree of freedom at the cable su''orts. 3e ha%e to use 'artial moment release at one end of cable su''orts to eliminate the message. 'artial moment release at one end of cable su''orts to eliminate the message.

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Short/uts 5eys used in Staad ,ro

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STAAD

A. Set up

1. Global coordinate for Structure : X : as x axis as usual Z

X Y

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Y : as y axis as usual

Z : perpendicular to paper to top

2. ocal coordinate for indi!idual "e"ber alon# the len#th of the "e"ber is taken as local X axis

$. %e"bers & 'odes

1. (reation of Geo"etry

2. General para"eters to be fixed ). Analysis

*. +esi#n

Geometry

'ode: co ordinate of all the points of the plan is to be calculated as

'ode X Y Z

1 aaa ,,, bbb

2 ccc ,,, ddd

)

File - 'e - /ndian desi#n code 0check

'e proect enter3

File 'a"e  3 4 location  3

en#th unit 5 Force 6nit 0check

Space 0 check

'ext enter3 Finish enter3

Node

Gi!e +ata for nodes

7ies a!ailable for Front5 back5 top & iso"etric 8t. (lick 0 labels 0 node no - apply - 9

;dit < =op "enu bar > to edit data

Add Beam :

to add bea" or to connect to nodes

=o "ethods of creatin# Structure +ata

1. 6sin# co""and file 2. 6sin# Graphical

user /nterface <G6/>

S=AA+ Screen %enu bar 0 on top =ool bar - on top ?a#e control 0 left side +ata area 08i#ht side %ain drain#

area 0 center

@After Add bea"5 #rid ill appear <4 or fro" snap node bea">

(reate < in +ata area> 6se linear 4 8adial 4 irre#ular

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Add beam from left to right & top to bottom.

'ode crusher 4 $ea" crusher : for selection of node or bea"

8t. (lick 0 labels 0 $ea" no 4 bea" orientation - apply - 9 (ha#e to /so"etric !ie 4 top

'ode crusher enter3

Select node < use ctrl key for "ultiple selection>

For column to repeat for floor

Geo"etry < =op "enu bar > 0 =ranslation repeat enter3 Global direction Y check3

'o of steps - xxx Step spacin# - xxx

ink step 0 0check <if reuired> 9k enter3

For beam to repeat for floor

(han#e to front !ie $ea" crusher select3

Select bea"s to be copied by rubber band "ethod 4 pickin# etc. Geo"etry < =op "enu bar > 0 =ranslation repeat enter3

Global direction Y check3 'o of steps - xxx

Step spacin# - xxx

ink step 0 0check <if reuired> 9k enter3

For foundation

Si"ilar to abo!e5 but y is -!e.

Select ection

General ! left ide of creen" # $roperty

Define

=ype of section

'ode bea" eble

7ie - Structure +ia#ra" 0 eble

'ode bea" eble

7ie - Structure +ia#ra" 0 eble

=o chan#e /nput 6nit /nput unit /con 4

=ool - set current input unit

%e"ber 9ffset

$ea" crusher <select> Specification pa#e icon 4 General - Spec. pa#e 6se both start & end point

=o #et %e"ber infor"ation Select - by all - all bea"s (o""and - pre analysis print - "e"ber property

=o 7ie)+ "odel 8t. (lick - structure 0 4 7ie - Structure dia#ra" "enu

=o edit input file ;dit input file 4 S=AA+ editor

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%aterial of section

For colu"n : ocal B C Global B

ocal x C Global y i.e len#th of colu"n ocal y C other side.

For $ea" : ocal y C Global y

ocal x C Global y i.e len#th of bea" ocal B C other side i.e. idth of bea".

Gi!e data enter3 add  enter 3 .

.

close  enter3

After selectin# the specific section in the property box5 the sa"e is assi#ned to the "e"bers. (trl - Select "e"ber - assi#n 0 sa!e enter 3

To ee the hape and i%e of column.

8t. (lick 0 labels 0 structure - section out line 0 apply - 9 For center line

8t. (lick 0 labels 0 structure - section out line 0 none - 9

To check the property of any ection i miing

Select < top "enu bar> - "issin# attributes - "issin# property enter3

Adding upport

General ! left ide of creen" #

Support

(reate < left side box> Fixed end

Add enter3 Front !ie

'ode crusher acti!e3 Select the supportin# nodes (olu"n section Y Z $ea" section Z Y

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Assi#n

To 'ie( (hole tructure

9n top "enu bar enter3

)oading

+efinition

<Seis"ic definition> General

oad - +efinition - ne (ode - /S 1DE) - 2,,2 Zone 0 <for Zone -)> - ,.1 8esponse Factor - 

/"portance Factor - 1 Soil factor 0 10 hard soil

20 "ediu" soft soil )0 soft soil Add Self ei#ht

@@@

Add (lose <Hind definition> Hind +efinition

=ype - 15 (o""ent - Hind -1 Add =ype - 1 Add /ntensity Iei#ht , , 1.D E

Add5 ;xposure factor - , (lose

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*( Load case for seismic load)

oad case detail Add

'u"ber - 15 oadin# =ype : Seis"ic 5=itle -load cae #*5 S in X dir Add (lose oad case - 15 Add Seis"ic load5 X direction5 Factor :1 Add (lose

'u"ber - 25 oadin# =ype : Seis"ic 5=itle -load cae #+5 S in <0>X dir Add (lose oad case - 25 Add Seis"ic load5 X direction5 Factor : 01 Add (lose

'u"ber - )5 oadin# =ype : Seis"ic5 =itle -load cae #,5 S in Z dir Add (lose oad case - )5 Add Seis"ic load5 Z direction5 Factor : 1 Add (lose

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Add

'u"ber - *5 oadin# =ype : Seis"ic 5 =itle -load cae #-5 S in <0>Z dir Add (lose oad case - *5 Add Seis"ic load5 Z direction5 Factor : 01 Add (lose

'u"ber - *5 =itle - load case -*5 S in <0>Z dir Add (lose oad case - *5 Add Seis"ic load5 Z direction5 Factor : 01 Add (lose JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ

*( Load case for Wind load)

'u"ber - 5 =itle -load cae #5 Hind in X dir Add (lose oad case - 5 Add Hind load5 +irection X <check> +efine y ran#e

%ini"u" 7alue < Gi!e data "ini"u" "ay be 2.1 "> %axi"u" !alue <#i!e data>

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Factor 1 Add (lose

'u"ber - 5 =itle -load cae #/5 Hind in <0>X dir Add (lose oad case - 5 Add Hind load5 +irection X <check> +efine y ran#e

Factor <01> Add

(lose

'u"ber - K5 =itle -load cae #05 Hind in Z dir Add (lose oad case - K5 Add Hind load5 +irection Z <check> +efine y ran#e

Factor 1 Add (lose

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Add

'u"ber - D5 =itle - load cae #15 Hind in <0>Z dir Add (lose oad case - D5 Add Hind load5 +irection Z <check> +efine y ran#e

Factor <01> Add

(lose

JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ

*( Load case for Dead load)

'u"ber - E5 =itle -load cae #25 +ead oad Add (lose oad case - E5 Add Floor oad ?ressure C <0> ). '4 "2

Y ran#e - <Gi!e "ini"u" and %axi"u" !alue as per floor condition.> +irection : Global Y Add (lose oad case - E5 Add Self ei#ht Add (lose

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Assi#n

*( Load case for Live load)

'u"ber - 1,5 =itle -load cae #*35 i!e oad Add (lose oad case - 1,5 Add Floor oad ?ressure C <0> 2 '4 "2

Y ran#e - <Gi!e "ini"u" and %axi"u" !alue as per floor condition.> +irection : Global Y

Add (lose

@@ <X ran#e and Z ran#e "ay be chan#ed as per reuire"ent under oad case 1, accordin# to floor siBe.>

*( Load case for Wall load)

'u"ber - 115 =itle -load cae #**5 Hall oad Add (lose oad case - 115 Add %e"ber oad 6nifor" force H1 : <0> 1 '4". +irection GY Add (lose Select

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Assi#n

@@ <oad "ay be accordin# to hei#ht and thick ness of all5

For stairs 5 the load "ay be calculated and the d1 5 d2 !alue "ay be #i!en. =he load is assi#ne after selectin# bea"s in each floor>

oad case - 115 Add %e"ber oad 6nifor" force H1 : <0> *. '4". +irection GY Add (lose Select Assi#n @@ <For parapets> oad case - 115 Add %e"ber oad 6nifor" force H1 : <0> 12 '4". +irection GY Add (lose Select Assi#n @@ <For Stairs> JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ *( Load Combination)

@oad case detail Add

+efine co"bination

'a"e : 4ombination )oad 4ae *+: 1<+ L > 'or"al

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Factor : 1

=ransfer dead & li!e loads to ri#ht <i.e. case E5 1,5 11 here i.e dead load5 li!e load5 all load> Add

close

+efine co"bination

'a"e : 4ombination )oad 4ae *,: 1. <+ L > 'or"al

Factor : 1.

=ransfer dead & li!e loads to ri#ht <i.e. case E5 1,5 11 here i.e dead load5 li!e load5 all load> Add

(lose

+efine co"bination

'a"e : 4ombination )oad 4ae *-: 1.2 <+ L L S in X> 'or"al

Factor : 1.

=ransfer dead & li!e loads to ri#ht <i.e. case E5 1,5 1151 here i.e dead load5 li!e load5 all load & Seis"ic in X direction>

Add (lose

+efine co"bination

'a"e : 4ombination )oad 4ae *: 1.2 <+ L L S in <0>X> 'or"al

Factor : 1.

=ransfer dead & li!e loads to ri#ht <i.e. case E5 1,5 1152 here i.e dead load5 li!e load5 all load & Seis"ic in <0>X direction>

Add (lose

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Si"ilarly co"bine loads for Seis"ic in both Z dir5 Hind in both X & BZ direction5 i.e oad case 10 21>

!55 Seimic Definition for Spro : 3- & on(ard

/n the seis"ic definition belo self ei#ht

1. =he "e"ber load copied and pasted ith load chan#in# to ei#ht 2. =he -!e si#n chan#ed to L !e si#n5 GY to be deleted

). Also5 the Floor load copied and pasted ith load chan#in# to ei#ht *. =he -!e si#n chan#ed to L !e si#n GY to be deleted

. =he li!e load "ay be reduced to ,. instead of 2 >

*( Analysis )

Analysis < fro" left side "enu bar> ?erfor" analysis

'o print 9

?re print acti!e

+efine co""and < 8t. Side of screen> Support infor"ation acti!e3

Add (lose

'ode crusher acti!e3

M ?rint support infor"ation  acti!e3 Select Supports

Assi#n (lose

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+efine co""and < 8t. Side of screen> oad ist acti!e3

=ransfer load list 12 < as foundation is #enerally desi#ned for  & + ith Factor of sefty 1> Support 8eaction acti!e3

Add (lose

'ode crusher acti!e3

M ?rint support reaction  acti!e3 Select Supports Assi#n (lose <?;8F98% A'AYS/S ?8/'= S6??98= /'F98%A=/9' 9A+ /S= 12 ?8/'= S6??98= 8;A(=/9' > JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ *( Design )

?ost print acti!e3

+efine co""and < 8t. Side of screen> oad ist acti!e3

=ransfer load list 1)021 Add close

+esi#n <left side "enu bar> (oncrete <left side "enu bar> (ode : /S * <ri#ht side "enu bar> Select para"eter

=ransfer all para"eters to left

=ransfer folloin# para"eters to ri#ht Fc Fy "ain Fy Secondary %ax %ain %in %ain %in Secondary

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9k

4hange unit to Ne(ton & mm

(lick on the fi# on top "enu bar 9r5

=ool Set current input unit

+efine ?ara"eter

Acti!e Fc : 2, '4 "2 Add (lose Fy %ain : *1 '4 "2 Add (lose Fy Seco. : *1 '4 "2 _Add _(lose

%ax %ain : 2,"" Add (lose %ax Sec : 1,"" Add (lose %in %ain : 12 "" Add (lose %in Sec : D"" Add (lose Select the structure

Assi#n the abo!e para"eters one by one Yes (o""and +esi#n $ea" Add +esi#n (olu"n Add (lose

+esi#n (olu"n Acti!e3

Select colu"n < $ea"s parallel to Y axis > Assi#n

Yes

+esi#n $ea" Acti!e3

Select $ea" < $ea"s parallel to X & Z axis > Assi#n

Yes AnalyBe 8un Analysis 7ie out put file

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+one 8esult

JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ

Fail

=o see hether any "e"ber fails in the output fie (lick on the Find <binocular fi#ure>

Fail 0 find next 4 %ark all for bea"s A+; <adeuate> 0 find next 4 %ark all for colu"ns

*( For Printing)

;dit

=ake picture ?icture - 1

=itle < e#. Support nodes> 9k

File

8eport Setup ?ictures

?icture -1 pass to ri#ht ?icture albu"

Full pa#e 9k File

?rint pur!ie report ;dit =ake picture

?icture - 2 (ontinue NN.

(opy out put file to ordn fie Select

(opy

?aste in ord file

*( To view outut file latter )

+onOt sa!e after run analysis 4 !iein# the output file

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7ie 9ption $ea" le!el 1. IoriBontal ali#n"ent 2. 7ertical ali#n"ent ). Font

*( "ode Level)

7ie 9ption $ea" le!el 1. IoriBontal ali#n"ent 2. 7ertical ali#n"ent ). Font

*( For use of torsion)

+esi#n

+efine ?ara"eter

=orsion to be option selected

*( For merge beam)

Select the to consecuti!e "e"bers to be "er#ed =ool "er#e selected "e"bers

%er#e (lose yes

*( To coy a node # member)

Select the ele"ent 8i#ht click

(opy ?aste

Gi!in# coordinate of X Y Z

*( !eta angle) For orientation along Global X axis

*( $elease)

*( %D from Auto cad Plan in FP& system)

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%o!e

Select obect

Specify the base point of displace"ent as top left corner +estination as ori#in For"at 6nits ;n#ineerin# to deci"al Scale Select obect

9ri#in ,.,2* <to con!ert to "eter> For coordinates

(o""and /+ enter3

E< or tools inuiry /+> Select point

<->!e Y considered as positi!e Z

*( Wall weig't)

1,P thick all

Hei#ht: ,.2D <all thickness L plaster>@ 1@ !,63.," @ 1E.2 n 4 "2 C_{1*. n 4 "}

<Floor hei#ht - bea" hei#ht> For parapets #enerally Q 2 n. 4 " at roof top and balcony

*( &eismic Parameter)

(ode /S 1ED)

Zone C ,.1 <for Bone ///>

/"portance factor C 1 For ordinary residential buildin# C 2 For hospital buildin#

8F C ) For ordinary construction C  For specific construction SS C 1 Soil Standard for hard soil

C 2 Soil Standard for "ediu" soil C ) Soil Standard for soft soil

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S= C 1 Structure =ype for 8(( fra"e C 2 Structure =ype for Steel fra"e C ) Structure =ype for 9ther

@@@

%e"ber ei#ht - no si#n

,R all load of #round floor for plinth bea"s

,R all load of #round floor and ,R load of first floor for #round floor roof bea"s and so on Floor ei#ht

+ead load full

i!e load 2R 5 if   )n4s" i!e load ,R 5 if  3 )n4s"