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Correct answer is (c) 450 MPa

The explanation: When plastic analysis is used, the YIELD stress of GRADE of steel used SHALL not EXCEED 450 MPa and the stress strain DISTRIBUTION of steel shall not be significantly different from those obtained for steels complying with IS 2062.

Correct answer is (d) SIMPLY supported beam

Explanation: First order analysis YIELDS bending moment EQUAL to those for a simply supported beam since material and FRAME are assumed to behave linearly and MEMBER instability effects and frame instability effects can be ignored.

Right answer is (c) member instability effects cannot be IGNORED

Easiest explanation: The following are the assumptions of FIRST order elastic analysis of rigid jointed frame : (i) MATERIALS BEHAVE linearly, (ii) yielding effects can be ignored, (iii) member instability effects such as those caused by axial compression can ignored, (iv) frame behaves linearly frame instability effects such as those caused by moments due to HORIZONTAL frame deflection, etc can be ignored.

Right CHOICE is (b) to calculate internal force EQUILIBRIUM in deformed GEOMETRY of structure

To explain: Basic OBJECTIVE of second ORDER elastic analysis is to calculate internal force equilibrium in deformed geometry of structure. In this P-Δ effect is also considered.

Correct choice is (d) not RESIST moment

The explanation is: In simple CONSTRUCTION, connection between members at their JUNCTION will not resist any appreciable moment and shall be assumed to be HINGED.

The CORRECT choice is (b) geometry of undeformed STRUCTURE

The best I can explain: In first order elastic analysis, EQUILIBRIUM is EXPRESSED in terms of geometry of undeformed structure. This assumption is valid when elastic displacement are small compared to DIMENSIONS of structure.

Right answer is (b) CONNECTIONS between MEMBERS at their junction have sufficient rigidity

To explain: In rigid construction, connections between members at their junction have sufficient rigidity to hold angles between members CONNECTED at joint, unchanged under load.

Right answer is (d) transverse displacement of one END of member relative to other end is not effectively prevented

The best I can explain: In sway frame, transverse displacement of one end of member relative to other end is not effectively prevented. Such MEMBERS and frames OCCUR in STRUCTURE which DEPEND on flexural action of members to resist lateral loads and sway.

Right choice is (a) 0.5%

The explanation: Notional HORIZONTAL force = 0.5% of FACTORED dead LOAD + vertical imposed load at that level. Notional horizontal force are applied to analyse a frame subjected to gravity loads, CONSIDERING sway stability of frame.

Right answer is (a) Elastic Analysis

To explain I WOULD SAY: The design action effects for design basis earthquake loads is OBTAINED by elastic analysis. The maximum credible earthquake load can be ASSUMED to correspond to load at which significant plastic hinges are FORMED and shall be obtained by plastic analysis.

Correct CHOICE is (a) 1.0

To ELABORATE: For limit state of SERVICEABILITY, the load combination is 1.0(DL +WL/EL), for limit state of STRENGTH, the load combination is 1.5(DL +WL/EL), where DL=Dead load,WL=wind load, EL=earthquake load.

Right CHOICE is (b) 0.8

Explanation: For limit STATE of strength, the LOAD COMBINATION is 1.2(DL+LL+WL/EL), for limit state of serviceability, the load combination is 1.0DL+0.8LL+0.8WL/EL, where DL=Dead load,LL=imposed load, WL=wind load, EL=earthquake load.

Correct option is (c) Dead load + wind load + earthquake load

To EXPLAIN I would say: According to IS code, it is assumed thatmaximum wind load and earthquake load will not OCCUR simultaneously on a structure. The following combination of LOADS with appropriate partial SAFETY factors may be considered : (i)Dead load + imposed load, (ii) Dead load + imposed load + earthquake load or wind load, (iii) Dead load + wind load or earthquake load, (iv) Dead load + erection load.

Correct answer is (d) 1.5

The EXPLANATION: For LIMIT state of strength, the load COMBINATION is 1.5(DL+LL), for limit state of SERVICEABILITY, the load combination is 1.0(DL+LL), where DL=Dead load, LL=imposed load.

Correct option is (d) 1185 N/m^2

For explanation: Vb = 44m/s, k1 = 1, K3 = 1,

for terrain with CLOSELY spaced buildings, height of building=20m, class A: k2=1.01 (from IS 875 Part 3)

 VZ = k1k2k3Vb = 1×1.01x1x44 = 44.44 m/s

pz = 0.6Vz2 = 0.6x(44.44)2 = 1184.95 N/m^2.

Correct CHOICE is (a) pz ∝ Vz^2

For explanation I would SAY: pz = 0.6Vz^2, where pz is in N/m^2 and Vzis in m/s. 0.6 factor DEPENDS on NUMBER of factors and mainly on atmospheric pressure and AIR temperature.

Right choice is (d) material of structure

Explanation: Wind Pressure at any height of structure depend on (i)velocity and DENSITY of AIR, (ii)height above ground LEVEL, (iii)shape and aspect ratio of building, (iv) topography of surrounding ground surface, (v)angle of wind ATTACK, (vi)solidity ratio or openings in the structure.

The correct ANSWER is (c) Vz ∝ Vb

The BEST I can explain: Vz = k1k2k3Vb , where k1=probability factor(risk coefficient), k2=terrain, HEIGHT and STRUCTURE size factor, k3=topography factor.

Right answer is (a) number of years, the reciprocal of which GIVES the probability of extreme wind exceeding given wind speed in any one year

For explanation I WOULD SAY: Wind load acting on structure varies from year to year based on wind speed and maximum that can be expected to occur at a given location only once in so MANY years. This PERIOD is called return period.

Correct answer is (d) 3 seconds

For explanation: Basic WIND speed is based on peak wind gust velocity averaged over a short interval of 3s and having return period of 50 YEARS and corresponds to mean above GROUND level in open terrain.

The correct option is (b) IS 875 Part 3

Easiest explanation: For design loads for BUILDINGS and structures for wind LOAD, IS 875-Part 3 given by Bureau of Indian STANDARDS is used.

The CORRECT answer is (b) inside to outside, outside to inside

To ELABORATE: Internal PRESSURE COEFFICIENT in a building is positive if acting from inside to outside and EXTERNAL pressure coefficient in a building is positive if acting from outside to inside. The pressure depends on degree of permeability of cladding and direction of wind.

The correct answer is (C) F = [ (Cpe – Cpi)APD].

BEST EXPLANATION: F = (Cpe – Cpi)A pd , where F=net wind force on element, Cpi= internal pressure coefficient, Cpe=external pressure coefficient,A=surface area of element, pd=design wind pressure.

The correct choice is (a) factor DENOTING the acceleration response spectrum of the structure subjected to earthquake ground vibrations

Best explanation: Structural response factor (Sa/g) is the factor denoting the acceleration response spectrum of the structure subjected to earthquake ground vibrations. It DEPENDS on NATURAL period of VIBRATION and damping of the structure. Response Reduction Factor(R)is the factor by which the actual base shear force is reduced. Zone Factor(Z) is factor to obtain the design spectrum. Importance Factor (I) is the factor used to obtain the design seismic force.

Right choice is (b) A = ZISa/2Rg

The EXPLANATION is: Design horizontal seismic COEFFICIENT is GIVEN by A = ZISa/2Rg, where Z is zone FACTOR, R is response reduction factor, I is importance factor, Sa/g is average response acceleration coefficient.

Right option is (c) DYNAMIC Analysis

Explanation: Dynamic analysis is used to OBTAIN design seismic force, and its distribution to DIFFERENT level ALONG the height of the building and to various lateral load resisting members.

The correct CHOICE is (a) Earthquake will not OCCUR simultaneously with wind

To explain: As PER IS 1893, it is assumed that earthquake is not likely to occur simultaneously with wind or maximum flood or maximum SEA waves.

Right option is (d) Minor earthquake should not cause any damage to the structure and the structure should be functional

For explanation: As per IS 1893, the following seismic philosophy is adopted

(i) Minor and frequent earthquakes should not cause any damage to the structure

(II) Moderate earthquake should not cause significant structural damage but could have some non structural damage(the structure should BECOME OPERATIONAL once the damage is repaired)

(iii) Major and infrequent earthquake should not cause collapse( structure will be dysfunctional for further USE, but will stand so that people can be evacuated and PROPERTY can be recovered).

Correct answer is (B) WIND of location

Explanation: The factors which influence earthquake resistance design are : (i) geographical location of STRUCTURE, (ii) site soil and FOUNDATION condition, (iii) importance of structure, (iv) dynamic CHARACTERISTICS of structure such as strength, stiffness, ductility and energy dissipation factor.

Right answer is (a) lesser

For EXPLANATION: STRUCTURES are designed for seismic forces which is LESS than expected seismic FORCE under strong earthquakes, if the structures were to remain linearly elastic.

Correct answer is (b) positive and negative BENDING moments

To explain I would say: BEAMS are designedto resist positive and negative bending moments at the same SECTION for EARTHQUAKE LOADS.

Right answer is (C) both tension and compression

For explanation: Earthquake are CYCLIC and INDUCE reversal of stresses. Hence as per seismic PHILOSOPHY, axially loaded members have to resist both tension and compression.

Right answer is (b) 1.3

The best explanation: In plastic design of steel structures, load FACTOR is 1.3 when combination of DEAD load, IMPOSED load and EARTHQUAKE load is considered i.e.1.3(DL +/- IL +/- EL ).

Correct ANSWER is (d) 1.7

Explanation: In plastic DESIGN of steel structures, load FACTOR is 1.7 when combination of dead load and earthquake load is CONSIDERED i.e.1.7(DL + EL) or 1.7(DL – EL).

The correct option is (c) IS 1893

To ELABORATE: IS 1893(Part 1) is used for designing a structure considering earthquake loads. For all other loads like dead LOAD, WIND load, IS 875 is used for DESIGN.

Right OPTION is (d) 0.55 kN/m^2

For explanation I would say: As per IS 875, for roofs of SLOPE greater than 10^o, the imposed load is REDUCED by 0.02 kN/m^2for every degree RISE in slope.

Therefore, Imposed load = 0.75 – 0.02*(20^o-10^o) = 0.55 kN/m^2.

The CORRECT choice is (B) 0.4 kN/m^2

Best explanation: As per IS 875, the minimum imposed load on roof truss should be 0.4 kN/m^2. For sloping roof UPTO 10˚, the imposed load is taken as 0.5 kN/m^2 if access is not PROVIDED and 0.75 kN/m^2 if access is provided.

Correct option is (a) 0.02 kN/m^2

To explain: As PER IS 875, for roofs of SLOPE greater than 10^o, the imposed load is taken as 0.75 kN/m^2 and reduced by 0.02 kN/m^2for EVERY degree rise in slope.

Right option is (b) Earthquake load

The explanation is: Imposed loads are GRAVITY loads other than dead load and cover factors such as OCCUPANCY by people, stored material etc. It is classified into FOLLOWING groups : (i)residential, (ii)educational, (iii)institutional, (iv)assembly halls, (v)office and business buildings, (vi)MERCANTILE buildings, (vii)industrial, (VIII)storage buildings.

Right option is (d) period of EXPOSURE

The best I can explain: The probability that a specific load will be EXCEEDED during LIFE of structure depends on period of exposure. It ALSO depends on magnitude of design load.

The correct option is (c) LOAD which will not be exceeded by certain probability during life of STRUCTURE

To explain I would SAY: Characteristic load is the load which will not be exceeded by certain ASSUMED or pre-assumed probability during life of structure. These loads are anticipated loads due to SELF weight, imposed load, snow, wind load, etc.

Correct answer is (B) second order moments ARISING from joint DISPLACED

To EXPLAIN I would SAY: Second order moments arising from joint displaced is called P-Δ effect and second order moments arising from member deflection is called P-δ effect.

Right option is (a) hydrostatic load

The BEST I can explain: Hydrostatic load is considered on LIQUID retaining STRUCTURES or hydraulic structures. Wave and current load is considered in marine and offshore structure. Earth pressure is considered in basements, retaining walls, column footings, etc.Dynamic load is DUE to earthquake and WIND.

The correct option is (d) IS 875

The BEST explanation: IS 875 (all 5 parts) is recommended by Bureau of Indian Standards for CALCULATING various types of loads on the structure. Part 1 is for DEAD loads, part 2 for imposed loads, part 3 for wind load, part 4 for SNOW loads and part 5 for special loads and combinations.