# Multiple choice question for engineering

## Set 1

1. What is plastic-collapse load?

a) load at which sufficient number of elastic hinges are formed

b) load at which sufficient number of plastic hinges are not formed

c) load at which sufficient number of plastic hinges are formed

d) load at which structure fails

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2. What is difference between plastic design and elastic design?

a) In plastic design, redistribution of bending moment is considered

b) In plastic design, redistribution of bending moment is not considered

c) In elastic design, redistribution of bending moment is considered

d) Both in plastic and elastic design, redistribution of bending moment is considered

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3. Which of the following is true in a fixed beam having concentrated load at one-third point?

a) first hinge is formed at centre of beam

b) after first hinge, moment at that point increases

c) after first hinge, moment at that point decreases

d) after first hinge, moment at that hinge remains constant

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4. In a fixed beam having concentrated load at one-third point, final ultimate load will be ____ than first hinge load.

a) 33% lower

b) 33% higher

c) 50% higher

d) 50% lower

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5. Which of the following statement is correct?

a) plastic limit load is obtained by multiplying working load with load factor

b) plastic limit load is obtained by dividing working load with load factor

c) working load is obtained by multiplying plastic limit load with load factor

d) working load is obtained by multiplying working load with load factor

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6. Cantilevers and over hanging beams collapse as _____

a) single-bar mechanism

b) double-bar mechanism

c) three-bar mechanism

d) does not collapse

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7. Single-span beams collapse as ________

a) single-bar mechanism

b) two-bar mechanism

c) three-bar mechanism

d) does not collapse

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8. Multi-span beams collapse in one span as ___________

a) does not collapse

b) single-bar mechanism

c) two-bar mechanism

d) three-bar mechanism

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9. Among which of the following is the location of plastic hinge?

a) at supports

b) at centre of beam

c) at points away from concentrated load

d) at centre for uniformly distributed load

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## Set 2

1. Structures designed using elastic analysis may be ______ than those designed using plastic analysis

a) lighter

b) heavier

c) of same weight

d) almost half times the weight

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2. Both elastic and plastic methods neglect ________

a) live load acting on structure

b) dead load acting on structure

c) deformations due to load

d) influence of stability

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3. What is buckling?

a) Structural behaviour in which a deformation develops in direction of plane perpendicular to that of load which produced it

b) Structural behaviour in which a deformation does not develop in direction of plane perpendicular to that of load which produced it

c) Structural behaviour in which a deformation develop in direction of plane parallel to that of load which produced it

d) Structural behaviour in which a deformation develops in direction of plane along that of load which produced it

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4. Which of the following relation about plastic moment is correct?

a) M_{p} = Z_{p} /f_{y}

b) M_{p} = Z_{p} + f_{y}

c) M_{p} = Z_{p}f_{y}

d) M_{p} = Z_{p} – f_{y}

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_{y}=f

_{y}/E

_{s}, nominal moment strength is referred as plastic moment and is given by M

_{p}= Z

_{p}f

_{y}, where Z

_{p}= ∫ydA is plastic section modulus and f

_{y}= yield stress.

5. What is plastic moment of resistance?

a) maximum moment in stress strain curve, the point where the curvature can increase indefinitely

b) maximum moment in stress strain curve, the point where the curvature can decrease indefinitely

c) minimum moment in stress strain curve, the point where the curvature can increase indefinitely

d) minimum moment in stress strain curve, the point where the curvature can decrease indefinitely

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6. In elastic stage, equilibrium condition is achieved when neutral axis ___________ and in fully plastic stage, it is achieved when neutral axis ___________

a) is above centroid of the section, divides the section into two parts of one-third area and two-third area

b) is below centroid of the section, divides the section into two parts of one-third area and two-third area

c) is above centroid of the section, divides the section into two equal areas

d) passes through centroid of the section, divides the section into two equal areas

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7. Which of the following relation is correct for plastic section modulus, Zo ?

a) Z_{p} = 2A(y_{1}+y_{2})

b) Z_{p} = A(y_{1}+y_{2})/2

c) Z_{p} = A(y_{1}+y_{2})/4

d) Z_{p} = 4A(y_{1}+y_{2})

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_{p}= A(y

_{1}+y

_{2})/2, where A= area of cross section, y

_{1}and y

_{2}are centroids of portion above and below neutral axis respectively. Plastic modulus is defined as combined statical moment of cross sectional area above and below the equal-area axis.

8. Which of the following relation is correct about shape factor, v?

a) v = Z_{p}+Z_{e}

b) v = Z_{p}Z_{e}

c) v = Z_{p}/Z_{e}

d) v = Z_{e}/Z_{p}

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_{p}/Z

_{e}= M

_{p}/M

_{y}, where Z

_{p}and Z

_{e}are plastic and elastic section modulus respectively, M

_{p}and M

_{y}are plastic and elastic moments respectively.

9. The shape factor does not depend on ___

a) material properties

b) cross sectional shape

c) moment of resistance

d) section modulus

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_{p}/Z

_{e}= M

_{p}/M

_{y}, where Z

_{p}and Z

_{e}are plastic and elastic section modulus respectively, Mp and My are plastic and elastic moments respectively. This ratio is the property of cross-sectional shape and is independent of material properties.

10. Match the pairs with correct shape factor

Cross section Shape factor (average or maximum) A) Circular (i) 1.8 B) Rectangular (ii) 1.14 C) wide flange I-section (about major axis) (iii) 1.7 D) Channels (about minor axis) (iv) 1.5

a) A-i, B-ii, C-iii, D-iv

b) A-iv, B-iii, C-ii, D-i

c) A-iii, B-iv, C-ii, D-i

d) A-iii, B-ii, C-iv, D-i

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_{p}/Z

_{e}= M

_{p}/M

_{y}. The shape factor for various cross section are (i) for circular = 1.7, (ii) for rectangular = 1.5, (iii) wide flange I-section (about major axis) = 1.09-1.18, average is 1.14, (iv) wide flange I-section (about minor axis) = 1.67, (v) channels (about major axis) = 1.16-1.22, average is 1.18, (vi) channels (about minor axis) = 1.8 .

## Set 3

1. Steel is mainly an alloy of

a) Iron and Carbon

b) Sulphur and Zinc

c) Zinc and tin

d) Phosphorous and Tin

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2. Which of the following is a disadvantage of Steel?

a) High strength per unit mass

b) High durability

c) Fire and corrosion resistance

d) Reusable

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3. Elastic Modulus of Steel is __________

a) 1.5 x 10^{9} N/mm^{2}

b) 2.0 x 10^{5} N/mm^{2}

c) 2.0 x 10^{5} N/m^{2}

d) 1.5 x 10^{9} N/m^{2}

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4. Unit mass of Steel = ________

a) 785 kg/m^{3}

b) 450 kg/m^{3}

c) 450 kg/cm^{3}

d) 7850 kg/m^{3}

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5. Poisson’s ratio of steel is ________

a) 0.1

b) 1.0

c) 0.3

d) 2.0

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6. Structural Steel normally has carbon content less than _______

a) 1.0%

b) 0.6%

c) 3.0%

d) 5.0%

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7. What is the permissible percentage of Sulphur and Phosphorous content in steel?

a) 0.1%, 0.12%

b) 1.0%, 3.0%

c) 3.0%, 1.0%

d) 1.0%, 1.0%

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8. What happens when Manganese is added to steel?

a) decreases strength and hardness of steel

b) improves corrosion resistance

c) decreases ductility

d) improves strength and hardness of steel

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9. Which of the following is the effect of increased content of Sulphur and Phosphorous in Steel ?

a) yields high strength

b) affects weldability

c) increases resistance to corrosion

d) improves resistance to high temperature

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10. Which of the following is added to steel to increase resistance to corrosion?

a) Carbon

b) Manganese

c) Sulphur

d) Copper

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11. Which of the following properties are affected due to addition of carbon and manganese to steel?

(i) tensile strength and yield property (ii) Ductility (iii) Welding (iv) Corrosion resistance

a) i and ii only

b) i and iii only

c) i, ii, iii

d) i and iv only

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12. Chrome and Nickel are added to Steel to improve _________

a) corrosion resistance and high temperature resistance

b) strength

c) ductility

d) weldablity

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## Set 4

1. The depth-to-thickness ratio of web connected to flanges along one longitudinal edge only when transverse stiffeners are not provided is _____ to meet serviceability criteria.

a) >180ε

b) ≥90ε

c) ≤90ε

d) >90ε

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2. The depth-to-thickness ratio of web when only transverse stiffeners are provided and 3d ≥ c ≥d, where c is clear distance between stiffeners and d is depth of web is_____ to meet serviceability criteria

a) ≤ 200ε_{w}

b) ≥ 200 ε_{w}

c) > 200 ε_{w}

d) ≤ 400 ε_{w}

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_{yw}), f

_{yw}is yield stress of web.

3. The depth-to-thickness ratio of web when only transverse stiffeners are provided and c < 0.74d, where c is clear distance between stiffeners and d is depth of web is_____ to meet serviceability criteria

a) ≤ 200 ε_{w}

b) ≥ 270 ε_{w}

c) > 200 ε_{w}

d) ≤ 270 ε_{w}

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_{w}≤ 200 εw, when 0.74d ≤ c ≤d, where c is clear distance between stiffeners and d is depth of web, ε

_{w}= √(250/f

_{y}w), f

_{y}w is yield stress of web.

4. What is the range of c to meet serviceability criteria when transverse and longitudinal stiffeners are provided at one level only, at 0.2d from compression flange and c/tw ≤ 250 ε_{w} ?

a) c < 0.74d

b) 0.74d ≤ c ≤ d

c) c ≥ d

d) c > 2d

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_{w}≤ 250 εw for 0.74d ≤ c ≤ d and d/t

_{w}≤ 340 ε

_{w}for c < 0.74d, where c is clear distance between stiffeners and d is depth of web, εw = √(250/f

_{y}w), f

_{y}w is yield stress of web.

5. When second longitudinal stiffener is provided, d/tw to meet serviceability criteria is

a) ≤ 400 ε_{w}

b) ≥ 400 ε_{w}

c) > 800 ε_{w}

d) ≤ 800 ε_{w}

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_{w}≤ 400 εw to meet serviceability criteria, where d is depth of web, ε

_{w}= √(250/f

_{yw}), f

_{yw}is yield stress of web.

6. When a plate girder bends, vertical compression in web is due to

a) downward vertical component of compression flange bending stress only

b) downward vertical component of tension flange bending stress only

c) downward vertical component of compression flange and upward vertical component of tension flange bending stress

d) upward vertical component of compression flange and downward vertical component of tension flange bending stress

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7. The d/t_{w} should be ___ to avoid buckling of compression flange into web when transverse stiffeners are not provided

a) ≥ 500 ε_{f}^{2}

b) ≤ 345 ε_{f}^{2}

c) ≥ 345 ε_{f}^{2}

d) ≤ 500 ε_{f}^{2}

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_{f}

^{2}, where d is depth of web, εf = √(250/f

_{yf}), f

_{yf}is yield stress of compression flange.

8. When only transverse stiffeners are provided and d/t_{w} < 345 εf to meet compression flange buckling criteria, the range of c should be

a) c ≥ 4.5d

b) c > 3d

c) c > 1.5d

d) c < 1.5d

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_{w}≤ 345 ε

_{f}

^{2}for c ≥ 1.5d, d/t

_{w}< 345 εf for c < 1.5d when only transverse stiffeners are provided, where c is clear distance between stiffeners, d is depth of web, εf = √(250/f

_{y}f), f

_{y}f is yield stress of compression flange.

9. The optimum depth of web of plate girder is given by

a) (k/f_{y})^{0.33}

b) (M_{z}k/f_{y})

c) (M_{z}k/f_{y})^{0.33}

d) (M_{z}k/f_{y})^{2}

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_{z}k/f

_{y})0.33, M

_{z}is moment resisted entirely by flanges, k = d/t

_{w}, d is depth of web, t

_{w}is thickness of web, f

_{y}= design strength of flanges.

10. The minimum area of flange angles with cover plate for riveted/ bolted plate girder should be

a) 1/6^{th} of calculated flange area

b) 1/3^{rd} of calculated flange area

c) 1/8^{th} of calculated flange area

d) 1/4^{th} of calculated flange area

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11. Which of the following angle should be ideally used in bolted plate girder flange?

a) bulb angle

b) equal angle

c) unequal angle with short leg horizontal

d) unequal angle with long leg horizontal

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12. For which of the following cases are equal angles preferred in bolted plate girder flange?

a) when large number of connectors are required to connect flange angle to web

b) when very few number of connectors are required to connect flange angle to web

c) for reducing cost

d) for aesthetic appearance

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13. Flange cover plates are used in plate girder when

a) flange cover plates are not used

b) for aesthetic appearance

c) when moment resisting capacity has to be increased

d) when moment resisting capacity has to be decreased

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14. The thickness of flange cover plate should be ______ flange angle in bolted connections

a) less

b) more

c) twice

d) can be more or less

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## Set 5

1. What are purlins?

a) beams provided in foundation

b) beams provided above openings

c) beams provided over trusses to support roofing

d) beams provided on plinth level

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2. Theoretically, purlins are generally placed at

a) only at panel points

b) only at edges

c) only at mid span

d) only at corners of roof

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3. Purlin section is subjected to

a) not subjected to bending or twisting

b) twisting only

c) symmetrical bending

d) unsymmetrical bending

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4. If purlins are assumed to be simply supported, the moments will be

a) wl^{2}/10

b) wl/8

c) wl/10

d) wl^{2}/8

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^{2}/8. If they are assumed to be continuous, the moments will be slightly less and taken as wl2/10. IS 800 recommends the purlins to be designed as continuous beams.

5. While erecting channel section purlins, it is desirable that they are erected over rafter with their flange

a) facing down slope

b) facing up slope

c) does not depend whether up slope or down slope

d) flanges are placed randomly

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6. Sag rods are provided at

a) one-third points between roof trusses

b) end of span

c) two-third points between roof trusses

d) are never provided

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7. Which of the following is not true about sag rods?

a) sag rods are provided at midway or at one-third points between roof trusses

b) these rods reduce the moment M_{yy}

c) these rods increase the moment M_{yy}

d) these rods result in smaller purlin sections

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_{yy}is reduced and thereby result in smaller purlin section. they are useful in keeping the purlins in proper alignment during erection until roofing is installed and connected to purlins.

8. When one sag rod is used, the moment about web axis

a) reduces by 50%

b) increases by 50%

c) increases by 75%

d) reduces by 75%

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9. The maximum bending moment for design of channel/I-section purlin is calculated by

a) Wl/10, where W= concentrated load

b) Wl/8, where W= concentrated load

c) W/10, where W= concentrated load

d) W/8, where W= concentrated load

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_{z}= Pl/10 and M

_{y}= Hl/10, where P= factored load along z-axis, H = factored load along y-axis, l= span of purlin (c/c distance between adjacent trusses).

10. The required section modulus of the channel/I-section purlin can be determined by

a) Z_{pz} = M_{y}γ_{m0}/f_{y} + (b/d)(M_{z}γ_{m0}/f_{y})

b) Z_{pz} = M_{z}γ_{m0}/f_{y} + (b/d)(M_{y}γ_{m0}/f_{y})

c) Z_{pz} = M_{z}γ_{m0}/f_{y} + 2.5(b/d)(M_{y}γ_{m0}/f_{y})

d) Z_{pz} = M_{y}γ_{m0}/f_{y} + 2.5(b/d)(M_{z}γ_{m0}/f_{y})

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_{pz}= M

_{z}γ

_{m0}/f

_{y}+ 2.5(b/d)(M

_{y}γ

_{m0}/f

_{y}), where γ

_{m0}is partial safety factor for material = 1.1, d is depth of trial section, b is the breadth of the trial section, M

_{z}and M

_{y}are factored bending moments about Z and Y axes, respectively, and f

_{y}is yield stress of steel. Since the above equation involves b and d of a section, trial section must be used and from the above equation , it is checked whether chosen section is adequate or not.

11. The design capacity of channel/I-section purlin is given by

a) M = Z_{p}/f_{y}

b) M = Z_{p}γ_{m0}f_{y}

c) M = Z_{p}γ_{m0}/f_{y}

d) M = γ_{m0}/f_{y}

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_{dz}= Z

_{pz}γ

_{m0}/f

_{y}and M

_{dy}= Z

_{p}yγ

_{m0}/f

_{y}, M

_{dz}and M

_{dy}are design moment capacity about Z and Y axes, respectively, Z

_{pz}and Z

_{p}y are plastic section modulus about Z and Y axes, respectively and f

_{y}is yield stress of steel. For safety, design moment capacity should be always greater than or equal to factored bending moments.

12. The check for design capacity of channel/I-section purlin is given by

a) M_{dz} ≤ 1.2Z_{ey}f_{y}/γ_{m0}, M_{dy} ≤ 2.4Z_{ez}f_{y}/γ_{m0}

b) M_{dz} ≤ Z_{ez}f_{y}/γ_{m0}, M_{dy} ≤ 1.2Z_{ey}f_{y}/γ_{m0}

c) M_{dz} ≤ γfZ_{ey}f_{y}/γ_{m0}, M_{dy} ≤ 1.2Z_{ez}f_{y}/γ_{m0}

d) M_{dz} ≤ 1.2Z_{ez}f_{y}/γ_{m0}, M_{dy} ≤ γfZ_{ey}f_{y}/γ_{m0}

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_{dz}≤ 1.2Z

_{e}zf

_{y}/γ

_{m0}, M

_{dy}≤ γyZ

_{ey}f

_{y}/γ

_{m0}, where M

_{dz}and M

_{dy}are design moment capacity about Z and Y axes, respectively, Z

_{e}z and Z

_{e}y are elastic section modulus about Z and Y axes, respectively and f

_{y}is yield stress of steel. Since in y-direction, the shape factor Z

_{p}/Z

_{e}will be greater than 1.2, γf is used instead of 1.2. If 1.2 is used the onset of yielding under unfactored loads cannot be prevented.

13. Which of the following relation is correct for design of channel/I-section purlin?

a) (M_{z}/M_{dz}) + (M_{y}/M_{dy}) ≥ 1

b) (M_{z}/M_{dz}) + (M_{y}/M_{dy}) ≤ 1

c) (M_{dz}/M_{z}) + (M_{y}/M_{dy}) ≤ 1

d) (M_{dz}/M_{z}) + (M_{dy}/M_{y}) ≥ 1

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_{z}/M

_{dz}) + (M

_{y}/M

_{dy}) ≤ 1 , where M

_{dz}and M

_{dy}are design moment capacity about Z and Y axes, respectively, and M

_{z}and M

_{y}are factored bending moments about Z and Y axes, respectively.

14. For which of the following slope of roof truss, angle section purlin can be used?

a) 25˚

b) 50˚

c) 75˚

d) 60˚

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15. The modulus of section required for angle section purlin is given by

a) Z = M/(0.66xf_{y})

b) Z = M/(1.33×0.66xf_{y})

c) Z = M/(1.33×0.66xf_{y})

d) Z = M/(1.33xf_{y})

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_{y}), M = maximum bending moment = wl

^{2}/10, w = unfactored uniformly distributed load, l = span of purlin, f

_{y}is yield stress. The gravity and wind loads are determined to calculate bending moment and both loads are assumed to be normal to roof truss.