The external wind pressure acting on a roof depends on
Degree of permeability of roof
Slope of roof
Both (A) and (B)
None of the above
Correct Answer :
B. Slope of roof
Related Questions
For a column of height L fixed in position and direction both at its top and bottom, its effective length, is
L
1/√2 × L
½ L
2L
For the buildings having a low permeability, the internal wind pressure acting normal to the wall and roof surfaces is taken as
Zero
±0.2 p
± 0.5 p
±0.7 p Where p is basic wind pressure
As per IS : 875, for the purposes of specifying basic wind velocity, the country has been divided into
4 zones
5 zones
6 zones
7 zones
A structural member subjected to tensile force in a direction parallel to its longitudinal axis, is generally known as
A tie
A tie member
A tension member
All the above
As per IS: 800, in the plastic design, which of the following pairs are correctly matched?
Working Loads Load factor
(i) Dead load 1.7
(ii) Dead Load + imposed load 1.7
(iii) Dead load + load due to wind or 1.3 seismic forces
(iv) Dead load + imposed load + load 1.7 due to wind or seismic forces
Of these statements
(i) and (ii) are correct
(i), (ii) and (iii) are correct
(ii) and (iii) are correct
Only (i) is correct
Tacking rivets in compression plates not exposed to the weather, have a pitch not exceeding 300 mm or
16 times the thickness of outside plate
24 times the thickness of outside plate
32 times the thickness of outside plate
36 times the thickness of outside plate
Hudson's formula gives the dead weight of a truss bridge as a function of
Bottom chord area
Top chord area
Effective span of bridge
Heaviest axle load of engine
Rivets connecting flange angles to cover plates in a plate girder are subjected to
Horizontal shear only
Vertical load only
Both (A) and (B)
None of the above
The gross section of the web of a beam is defined as
Depth of the beam multiplied by its web thickness
Width of the flange multiplied by its web thickness
Sum of the flange width and depth of the beam multiplied by the web thickness
None of these
The web crippling due to excessive bearing stress can be avoided by
Increasing the web thickness
Providing suitable stiffener
Increasing the length of the bearing plates
None of the above
The allowable tensile stress in structural mild steel plates for steel tank is assumed as
95.0 MPa on net area
105.5 MPa on net area
105.5 MPa on gross area
150.0 MPa on gross area
The maximum permissible slenderness ratio of compression member carrying dead and superimposed load, is
180
200
250
350
Load factor is
Always equal to factor of safety
Always less than factor of safety
Always greater than factor of safety
Sometimes greater than factor of safety
With usual notations of the letters, the shear stress fs at any point of the cross-section is given by
fs =FQ/It
fs =Ft/IQ
fs =It/FQ
fs =IF/Qt
The mechanism method and the statical method give
Lower and upper bounds respectively on the strength of structure
Upper and lower bounds respectively on the strength of structure
Lower bound on the strength of structure
Upper bound on the strength of structure
The strength of ISA 125 = 75 × 10 mm used as a tie member with its longer leg connected at the ends by 27 mm diameter rivets, is
26,000 kg
26,025 kg
26,050 kg
26,075 kg
The number of seismic zones in which the country has been divided is
3
5
6
7
The size of a butt weld is specified by the effective throat thickness which in the case of incomplete penetration, is taken as
½ of the thickness of thicker part
¾ of the thickness of thicker part
¾ of the thickness of thinner part
7/8 of the thickness of thinner part
The external wind pressure acting on a roof depends on
Degree of permeability of roof
Slope of roof
Both (A) and (B)
None of the above
Area of openings for buildings of large permeability is more than
10% of wall area
20% of wall area
30% of wall area
50% of wall area
In factory buildings, the horizontal beams spanning between the wall columns supporting a wall covering, are called
Stringers
Trimmers
Girts
Lintels
The difference between gross diameter and nominal diameter for the rivets up to 25 mm diameter is
1.0 mm
1.5 mm
2.0 mm
2.5 mm
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).
8 t
16 t
24 t
32 t
Pick up the correct statement from the following:
Vertical stiffeners may be placed in pairs one on each side of the web
Single vertical stiffeners may be placed alternately on opposite sides of the web
Horizontal stiffeners may be placed alternately on opposite sides of the web
All the above
The effective length L of a simply supported beam with ends restrained against torsion, and also the ends of compression flange partially restrained against lateral bending, is given by
L = span
L = 0.85 span
L = 0.75 span
L = 0.7 span
The use of tie plates in laced columns is
Prohibited
Not prohibited
Permitted at start and end of lacing system only
Permitted between two parts of the lacing
Web crippling generally occurs at the point where
Bending moment is maximum
Shearing force is minimum
Concentrated loads act
Deflection is maximum
The elastic strain for steel is about
1/12 of strain at the initiation of strain hardening and about 1/120 of maximum strain
1/2 of strain at the initiation of strain hardening and about 1/12 of maximum strain
1/12 of strain at the initiation of strain hardening and 1/200 of maximum strain
1/24 of strain at the initiation of strain hardening and about 1/200 of maximum strain
The effective length of a battened column is increased by
5 %
10 %
15 %
20 %
In case of timber structures, the simple bending formula M = fz may be applied for
Rectangular beams up to 300 mm depth
All rectangular beams
Solid circular beams only
All square cross-section beams