``` 1. spacing of lacing C /r.min L1 /40, or L1 /60 λl = K.L1 /r 2.B > centroidal distance between main members ```

steel design Flashcards by deepak singh

shape factors of sections

hollow circle - 1.27
circular plate - 1.7
diamond section- 2
triangular section- 2.34

How well did you know this?

Not at all

Perfectly

Center of gravity of semi circles

semi circular line = 2R /pi
semi circular plate =4R/3pi
hemisphere = 3R/8

How well did you know this?

Not at all

Perfectly

ultimate plastic load for propped cantiliver

11.656 Mp / L^2

hinge at x= 0.414 L

How well did you know this?

Not at all

Perfectly

maximum permissible deflection in SSB

table 6 is 800:2007
elements succeptible to cracking = L/300
not succeptible to cracking = L /240
for cantiliver = L/150 and L/120

How well did you know this?

Not at all

Perfectly

limiting grip length in lap joint

Lg < 5d
effect of bending stress can be ignored in above condition
8d >Lg > 5d , reduction factor required
Lg > 8d , redesign required

How well did you know this?

Not at all

Perfectly

minimum pitch, guage , end distance

pitch/guage = 2.5 bolt
end = 1.5 hole
= 1.7 hole (for hand cut element)

How well did you know this?

Not at all

Perfectly

maximum edge , pitch distance in welds and bolts

end distance = 12 t.e , e = sqrt(250/fy)
comp pitch distance = 12t or 200 mm
tension pitch distance = 16t or 200 mm
in case of staggered = 1.5* distances

How well did you know this?

Not at all

Perfectly

maximum pitch of tack bolt

for plates, flats = 32 t or 300 mm
if exposed to weather 16t or 200 mm
for compression = 600mm or λ1 <40 , 0.6λ
for tension member = 1000 mm

How well did you know this?

Not at all

Perfectly

bolt and bolt hole

dia = 6.06 sqrt(t)      Unwins formula
nominal dia : hole clearence
12 ~ 14 mm : 1mm
16 ~ 24 mm : 2mm 
 > 24 mm   : 3mm

How well did you know this?

Not at all

Perfectly

slot welding size limitation

width of slot > 25mm or 3.t

How well did you know this?

Not at all

Perfectly

long joints, weld and bolt unbuttening effects

L > 150 throat

L > 15 bolt

How well did you know this?

Not at all

Perfectly

slenderness ratio limits of steel members

λ < 180 , compression member
λ < 180 , tension member, but stress reverse due to
live load
λ < 250 , for wind earthquake loads
λ < 350 Tension member but reversal of stress due to wind load
λ < 400 , for tension members

How well did you know this?

Not at all

Perfectly

net tearing area of staggered bolting

[ B -n.D +(S^2) /4g ] * t

How well did you know this?

Not at all

Perfectly

lug angle design

minimum bolts at lug > 2 bolt
number of bolts at locations 
n1 = Fconnect /Rv
n2= 1.4* Fout /Rv
n3= 1.2* Fout /Rv
n2 interconnecting bolt must start in advance

How well did you know this?

Not at all

Perfectly

design of bolted connection

find dia of bolt = 6.04 *sqrt(t)
find rivit value
find no of bolts required
arrangement of bolts
width and thickness of plates
efficiency of joint (if asked)

How well did you know this?

Not at all

Perfectly

design of lacing

1. spacing of lacing
 C /r.min  <50 or 0.7*λ
2. dimension of lacing
 t > L1 /40, or L1 /60 
 λl = K.L1 /r < 145 (K=0.7 for double lacing or welded )
3. Forces in Lacing
 V= 2.5% of Pu
 F = V/ N*sin()
4. Forces < strength compressive and tensile
 T= 0.9fu Anet /1.25
 T= Ag * fy /1.2
 C= fcd* Ag (fcd depends on λl)
5. tie plate or batten plate 
 Dend > 2.B
           > centroidal distance between main members

How well did you know this?

Not at all

Perfectly

width of lacing bars

bolt dia mm - width of lacing bar
16 - 50
18  - 55
20- 60
22- 65

How well did you know this?

Not at all

Perfectly

to prevent web crippling

A = a +2.5*h2

How well did you know this?

Not at all

Perfectly

to prevent web buckling

find K.l /r =2.45d / tw
fcd *Ag > R
A= a + d (1:1 dispersion)

condition of plastic , compact and semi compact rolled I-section

b/tf < 9.4 e
d /tw < 84e

compact
b/tf < 10.5 e
d /tw < 105e

semi compact
b/tf < 15.7 e
d /tw < 126e

bolt grade 4.6

400 mpa strength

Kb in bearing of bolt

Kb =min [e/3d , p/3d -0.25, fub/fu, 1]

rivit hole size

d' = d+ 1.5     for d<25
d' = d + 2      for d>25

carbon content in mild steel

0.23%

characterstics of steel used as plasstic steel

fy < 450 Mpa fu/fy > 1.2 εplastic > 1.15*εelastic

what is stainless steel made of

iron and chromium

minimum size of weld based on size of thicker plate

``` thicker plate min size of weld <10 mm 3mm 11 ~ 20 mm 5mm 21~32 mm 6mm >32mm 8mm ```

maximum size of weld

T - 1.5mm | 0.75 T

reasons of flange buckling, web buckling, web crippling

Flange buckling - Bending compression Web buckling - Diagonal compression web crippling - Bearing stress

permissible deflections in gantry girder

span/500 manual operated span/750 electrically operated span/1000 capacity > 50t

use criteria of stiffners in Plate girders

d1/tw >90, verticle stiffners for web buckling d1/tw > 200, horizontal stiffners at 0.2d from flange d1/tw > 250, horizontal at N.A d1/tw > 400, section redesign

end bearing stiffners Leff, area

Leff = 0.7*L1 A = 4*Aoutstand + 40*tw*tw designed as columns so tight bearing

outstand Area of outstand leg

A2e= k*A2 k = 3*A1 /(3A1+A2) Ae = A1 + k*A2 , 0.875A in case of symmetric angle

for field rivets , permissible stresses are reduced by what percentage?

10%

The critical slope of a roof truss above which snow load need not be considered.

50 degree

slenderness ratio of bracing for hangers

160

if beams arent restrained by cleats at ends for torsion

Length increased by 20%

design wind speed factors k1, k2, k3

``` k1 = risk cofficient k2 = terrain, height , size factor k3 = topography factor ```

The depth of web of a plate girder usually varies between

1/8 to 1/12 of the span.

From serviceability requirement the web is considered to be unstiffened if the spacing of transverse stiffeners is greater than

3 times the web depth.

batten design properties

Column is divided into a minimum of three bays (i.e. minimum 4 number of battens required). - Thickness of batten plate shall not be less than 1/50th the distance between outer most connecting line of rivets of welds. ``` - (i) Effective depth of intermediate battens > 0.75 α > 2 *b*g {b = width of column component α= spacing of C.G. of column} ``` (ii) Effective depth of end battens > α > 2*b

approximate are of web and flange contributing in strength of plate girder

Aeff = Aflange + (1/6)*Aweb

maximum spacing of purlins in asbestos roofing

1.4 m

Max Moment in continuous members like purlin

w.L^2 /10

Effective length of compression flanges depending on end conditions

Effective length of compression flanges depending on end conditions ends of compression flange unrestrained = L ends of compression flange partially restrained = 0.85L ends of compression flange fully restrained = 0.7 L cantilevers -built in support, free at end = 0.85L -built in support, restrained against torsion at end by continuous construction = 0.75L -built in support, restrained against torsion at end by cross members over several beams = 0.5L - continuous and unrestrained against torsion at support and free at end = 3L - continuous and partially restrained against torsion at support and free at end = 2L continuous and restrained against torsion at support and free at end = L