Steel design Flashcards
For determination of allowable stress in axial compression, Indian Standard Institution has adopted
[A]. Euler's formula [B]. Rankine formula [C]. Engesser formula [D]. Secant formula @ [E]. Perry Robertson formula.
- Secant formula was used in earlier version of IS:800 prior to 1984.
- IS:800-1984 recommended Merchant-Rankine formula.
- IS:800-2007 recommend the Perry Roberston formula (see clause 7.1.2.1, pg no-34 of IS:800-2007).
According to IS : 800 - 71, the minimum thickness of a vertically stiffened web plate, shall not be less than
B is correct.
No stiffeners are provided if the web is more than d/85.
Vertical stiffeners are provided if the web is less than d/85 but more than d/200.
Vertical +1horizontal stiffeners are provided if the web is more than d/200 but less than d/250 (in this case this 1 horizontal stiffener is usual to place at 2/5th of the depth of neutral axis from the compression flange).
Vertical +2 horizontal stiffeners are provided if the web is less than d/250 (in this case this 2nd horizontal stiffener is usually placed at neutral axis).
A fillet weld may be termed as
[A]. mitre weld
[B]. concave weld
[C]. convex weld
[D]. all the above. @
Mitre weld - Hypotenus of weld is in straight line.
Concave weld - Hypotenus of weld will be concave shape.
Convex weld - Hypotenus of weld will be in convex shape.
The minimum edge distance of a rivet line connecting two or more plates, is kept equal to 37 mm plus (where t is the thickness in mm of the thinner outside plate).
[A]. 2 t [B]. 4 t @ [C]. 6 t [D]. 8 t [E]. 10 t
By is 800:2007 clause 10.2.4.3 e max is 40mm + 4t.
Max gauge length is 100 + 4t or 200.
Max edge 12 (τ).
Max edge for corrosion 40 + 4t.
If d is the distance between the flange angles, the vertical stiffeners in plate girders are spaced not greater than
[A]. d
[B]. 1.25 d
[C]. 1.5 d @
[D]. 1.75 d
Yes, sir right as per design criteria of vertical stiffener minimum spacing 0.33d &max 1.5d.
The thickness t of a single flat lacing should not be less than
[A]. 1/30 th length between inner end rivets
[B]. 1/40 th length between inner end rivets @
[C]. 1/50 th length between inner end rivets
[D]. 1/60 th length between inner end rivets
[E]. none of these.
1/40 for single lacing and 1/60 for double lacing.
The spans are considered approximately equal if the longest span does not exceed the shortest span by more than
[A]. 5%
[B]. 10%
[C]. 15% @
[D]. 20%
The spans are considered approximately equal if the longest span does not exceed the shortest span by more than
[A]. 5%
[B]. 10%
[C]. 15% @
[D]. 20%
If the depth of the section of an upper column is smaller than the lower column
[A]. filler plates are provided with column splice
[B]. bearing plates are provided with column splice
[C]. neither filler plates nor bearing plates are provided with column splice
[D]. filler plates and bearing plates are provided with column splice @
[E]. none of these.
If the thickness of the upper plate is slightly less than the lower plate then we use a filler plate.
But when upper plate thinner & not able to take them in that case we use a bearing plate.
The permissible bearing stress in steel, is
[A]. 1500 kg/cm2 [B]. 1890 kg/cm2 @ [C]. 2025 kg/cm2 [D]. 2340 kg/cm2 [E]. 2250 kg/cm2
0.75 fy = 0.75 * 250 = 1890 (approx).
When a load is transferred through one surface to another surface in contact, the stress is known as
[A]. tensile stress [B]. compressive stress [C]. shearing stress [D]. working stress [E]. none of these. @
Answer : Bearing stress.
Bearing stress is defined as the stress that results from the contact of two members.
For steel members not exposed to weather, the thickness of steel should not be less than
[A]. 4.5 mm
[B]. 6 mm @
[C]. 8 mm
[D]. 10 mm
The number is primary or secondary type if it is not given how we can say that it is 6 mm or 4.5 mm if the member is main member then given an answer is correct and if the member secondary then correct answer will be 4.5 mm.
Exposed to weather and inaccessible = 8mm.
Exposed to weather and accessible = 6mm.
The beams supporting the steps of a stair are generally known as
[A]. headers
[B]. trimmers
[C]. stringers @
[D]. spandrel beams.
stringer = central beam in stair
sprendel beam = take load of slabs and pass to column
If the slenderness ratio is greater than 160, the allowable stress in axial compression is multiplied by a factor (1.2 - (l/xy) where x is
[A]. 200 [B]. 400 [C]. 600 [D]. 800 @ [E]. 1000
If the slenderness ratio is greater than 160, the allowable stress in axial compression is multiplied by a factor (1.2 - (l/xy) where x is
[A]. 200 [B]. 400 [C]. 600 [D]. 800 @ [E]. 1000
If d is the distance between the flange angles, the vertical stiffeners in plate girders without horizontal stiffeners, are spaced at a distance not less than
[A]. 0.15 d
[B]. 0.22 d
[C]. 0.33 d @
[D]. 0.44 d
Max Spacing of vertical stiffners = 1.5d.
Min Spacing of vertical stiffners= 0.33d.
If W and L are the total superimposed load and the span of a plate girder in metres, the approximate self weight (W) of the girder, is taken as
The wt of bolted/riveted plate girder = WL/300.
For welded plate girders = WL/400.
The ratio of the span L of the filler joists to the depth d from the under side of the joist to the top of the structural concrete, should not exceed
[A]. 60 [B]. 45 [C]. 35 @ [D]. 25 [E]. 20
35
The effective length of a double angle strut with angles placed back to back and connected to both the sides of a gusset plate, by not less than two rivets, is
[A]. 0.5 L [B]. 0.67 L [C]. 0.85 L @ [D]. L [E]. 2 L
For strut,
Double angle placed back to back on opposite sides,
Leff=0.7L to 0.85L.
To the calculated area of cover plates of a built-up beam, an allowance for rivet holes to be added, is
[A]. 10% [B]. 13% @ [C]. 15% [D]. 18% [E]. 20%.
13%
Allowable working stress corresponding to the slenderness ratio of double angles placed back to back and connected to one side of a gusset plate, is reduced to
[A]. 50% [B]. 60% [C]. 70% [D]. 80% @ [E]. 40%
[D]. 80% @
Cold driven rivets range from
[A]. 6 to 10 mm in diameter [B]. 10 to 16 mm in diameter [C]. 12 to 22 mm in diameter @ [D]. 22 to 32 mm in diameter [E]. none of these.
Cold driven rivets range from
[A]. 6 to 10 mm in diameter [B]. 10 to 16 mm in diameter [C]. 12 to 22 mm in diameter @ [D]. 22 to 32 mm in diameter [E]. none of these.
For the economical design of a combined footing to support two equal column loads, the projections of beams in lower tier are kept such that bending moment under column is equal to
[A]. bending moment at the centre of the beam @
[B]. half the bending moment at the centre of the beam
[C]. twice the bending moment at the centre of the beam
[D]. none of these.
For the economical design of a combined footing to support two equal column loads, the projections of beams in lower tier are kept such that bending moment under column is equal to
[A]. bending moment at the centre of the beam @
[B]. half the bending moment at the centre of the beam
[C]. twice the bending moment at the centre of the beam
[D]. none of these.
When plates are exposed to weather, tacking rivets are provided at a pitch in line not exceeding (where t is the thickness of the outside plate).
[A]. 8 t [B]. 16 t @ [C]. 24 t [D]. 32 t [E]. 48 t
When plates are exposed to weather, tacking rivets are provided at a pitch in line not exceeding (where t is the thickness of the outside plate).
[A]. 8 t [B]. 16 t @ [C]. 24 t [D]. 32 t [E]. 48 t
The side thrust T on the tie rods provided at the end beam of jack arch of rise R, is calculated from the formula
WL /8R
When the depth of a plate girder is at least n times the depth of vertical leg of the flange angles, the girder is known as deep plate girder, if n is
[A]. 2 [B]. 4 [C]. 6 [D]. 8 @ [E]. 10
When the depth of a plate girder is at least n times the depth of vertical leg of the flange angles, the girder is known as deep plate girder, if n is
[A]. 2 [B]. 4 [C]. 6 [D]. 8 @ [E]. 10
The greatest permissible clear dimension of the web of thickness t in the panel of a plate girder, is restricted to
[A]. 180 t [B]. 220 t [C]. 230 t [D]. 260 t [E]. 270 t @
The greatest permissible clear dimension of the web of thickness t in the panel of a plate girder, is restricted to
[A]. 180 t [B]. 220 t [C]. 230 t [D]. 260 t [E]. 270 t @
As per ISI, rolled steel beam sections are classified into
[A]. two series
[B]. three series
[C]. four series
[D]. five series. @
Rolled steel beam sections mean, I sections.
Five series of rolled steel I section is manufactured in India.
(A) ISJB - INDIAN STANDARD JUNIOR BEAMS. (B) ISLB - INDIAN STANDARD LIGHT BEAMS. (C) ISMB - INDIAN STANDARD MEDIUM BEAMS. (D) ISHB - INDIAN STANDARD HEAVY BEAMS. (E) ISWB - INDIAN STANDARD WIDE FLANGED BEAMS.
The size of a butt weld is specified by the effective throat thickness which in the case of incomplete penetration, is taken as
[A]. of the thickness of thicker part [B]. of the thickness of thicker part [C]. of the thickness of thinner part [D]. of the thickness of thinner part @ [E]. none of these.
The effective throat thickness in case of incomplete penetration butt weld is taken as 7/8th of the thickness of the thinner part joined.
But for the purpose of stress calculation, a required effective throat thickness not exceeding 5/8th of the thickness of thinner part joined should be used.
Length of an outstanding leg of a vertical stiffener, may be taken equal to
[A]. th of clear depth of the girder plus 15 mm
[B]. th of clear depth of the girder plus 20 mm
[C]. 1/25th of clear depth of the girder plus 25 mm @
[D]. th of clear depth of the girder plus 50 mm
[E]. th of clear depth of the girder plus 50 mm.
[C]. 1/25th of clear depth of the girder plus 25 mm @
Modified moment of inertia of sections with a single web, is equal to moment of inertia of the section about Y-Y axis at the point of maximum bending moment and is multiplied by the ratio of
[A]. area of compression flange at the minimum bending moment to the corresponding area at the point of maximum bending moment
[B]. area of tension flange at the minimum bending moment of the corresponding area at the point of maximum bending moment
[C]. total area of flanges at the maximum bending moment to the corresponding area at the point of maximum bending moment @
[D]. none of these.
Modified moment of inertia of sections with a single web, is equal to moment of inertia of the section about Y-Y axis at the point of maximum bending moment and is multiplied by the ratio of
[A]. area of compression flange at the minimum bending moment to the corresponding area at the point of maximum bending moment
[B]. area of tension flange at the minimum bending moment of the corresponding area at the point of maximum bending moment
[C]. total area of flanges at the maximum bending moment to the corresponding area at the point of maximum bending moment @
[D]. none of these.
For a cantilever beam of length L continuous at the support and unrestrained against torsion at the support and free at the end, the effective length l is equal to
[A]. l = L [B]. l = 2L [C]. l = 0.5L [D]. l = 3L @ [E]. l = 3.5L
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
The least permissible clear dimension of the web of thickness t in the panel of a plate girder, is restricted to
[A]. 150 t [B]. 160 t [C]. 170 t [D]. 180 t @ [E]. 200 t
The least permissible clear dimension of the web of thickness t in the panel of a plate girder, is restricted to
[A]. 150 t [B]. 160 t [C]. 170 t [D]. 180 t @ [E]. 200 t
A beam may be designed as a cased beam if
[A]. section is of double open channel form with the webs not less than 40 mm apart
[B]. overall depth and width of the steel section do not exceed 750 and 450 mm respectively.
[C]. beam is solidly encased in concrete with 10 mm aggregate having 28 days strength 160 kg/cm2
[D]. width of the solid casing is kept at least 100 mm more than the width of the steel flange and having a concrete cover of 50 mm
[E]. all the above. @
A beam may be designed as a cased beam if
[A]. section is of double open channel form with the webs not less than 40 mm apart
[B]. overall depth and width of the steel section do not exceed 750 and 450 mm respectively.
[C]. beam is solidly encased in concrete with 10 mm aggregate having 28 days strength 160 kg/cm2
[D]. width of the solid casing is kept at least 100 mm more than the width of the steel flange and having a concrete cover of 50 mm
[E]. all the above. @
The minimum width B of a solid casing for a cased beam, is equal to
[A]. B = b + 25 mm [B]. B = b + 50 mm [C]. B = b + 75 mm [D]. B = b + 100 mm @ [E]. B = b + 125 mm
I think the Cased beam is a combination of steel structural beam then encased with reinforced concrete. The minimum width B is the width of steel section flange plus 100mm.
In factory buildings, the horizontal beams spanning between the wall columns supporting a wall covering, are called
[A]. stringers
[B]. trimmers
[C]. girts @
[D]. lintels.
In factory buildings, the horizontal beams spanning between the wall columns supporting a wall covering, are called
[A]. stringers
[B]. trimmers
[C]. girts @
[D]. lintels.
Rise of a Jack arch is kept about
[A]. 1/2 to 1/3 of the span
[B]. 1/3 to 1/4 of the span
[C]. 1/4 to 1/8 of the span
[D]. 1/8 to 1/12 of the span. @
Rise of a Jack arch is kept about
[A]. 1/2 to 1/3 of the span
[B]. 1/3 to 1/4 of the span
[C]. 1/4 to 1/8 of the span
[D]. 1/8 to 1/12 of the span. @
Compression members composed of two channels back-to-back and separated by a small distance are connected together by riveting so that the minimum slenderness ratio of each member between the connections, does not exceed
[A]. 40 @
[B]. 50
[C]. 60
[D]. 70
Yeah its the tracking rivets and either its 40 or 0.6 times the most unfavorable slenderness ratio of the strut as a whole.
