Test 35 - Gantry Girders

Question 1 ప్రశ్న 1

Which statement correctly describes the principal current-code framework for an ordinary structural-steel gantry girder supporting an overhead crane?

A Crane load effects are obtained from IS 875 (Part 2):1987 as applicable, while the steel girder is designed using IS 800:2007 with its applicable amendments B All crane loads and steel strengths are governed only by IS 456:2000 C IS 808:2021 alone supplies both crane loads and gantry-girder design resistance D Crane impact and horizontal forces are ignored in Limit State Design

Question 2 ప్రశ్న 2

What is the principal structural function of a gantry girder in an industrial building with an overhead travelling crane?

A To support the crane rail and transfer moving vertical and horizontal crane actions to the supporting columns or brackets B To support only the roof sheeting above the crane bay C To act only as a tension tie between columns D To carry the building foundation directly on the crane wheels

Question 3 ప్రశ్న 3

An overhead crane has a 20 m span between rails. Its bridge self-weight is 200 kN and acts symmetrically, while the combined lifted load plus crab weight is 300 kN located 2 m from the left rail. There are two wheels on each side of the crane. What is the maximum static wheel load on the left gantry girder?

A 130 kN B 150 kN C 185 kN D 370 kN

Question 4 ప్రశ్న 4

For the 185 kN maximum static wheel load in the previous question, what vertical wheel load should be considered on the electric overhead-crane gantry girder after applying the IS 875 (Part 2) 25 percent impact allowance?

A 203.5 kN B 222.0 kN C 231.25 kN D 277.5 kN

Question 5 ప్రశ్న 5

Which statement correctly distinguishes the IS 875 (Part 2) vertical impact allowances for electric overhead cranes?

A Crane girders use 25 percent for all crane classes; supporting columns use 25 percent for Class III and IV and 10 percent for Class I and II; foundations receive no such additional vertical impact load B Crane girders use 10 percent for all classes and foundations use 25 percent C Only the foundations receive a 25 percent impact allowance D All crane girders, columns and foundations always use exactly 10 percent

Question 6 ప్రశ్న 6

A hand-operated crane produces a maximum static wheel load of 160 kN on a gantry girder. What vertical wheel load is obtained after applying the IS 875 (Part 2) impact allowance applicable to the crane girder?

A 160 kN B 168 kN C 176 kN D 200 kN

Question 7 ప్రశ్న 7

For an ordinary electric overhead crane without a rigid suspension mast, the combined crab weight and lifted load is 300 kN. According to IS 875 (Part 2), what total horizontal force transverse to the rails acts on one crane track rail, and what is the force per wheel if there are two wheels on that side?

A 15 kN total and 7.5 kN per wheel B 30 kN total and 15 kN per wheel C 7.5 kN total and 3.75 kN per wheel D 25 kN total and 12.5 kN per wheel

Question 8 ప్రశ్న 8

An electric overhead crane has a rigid mast for suspension of the lifted load. If the combined crab and lifted load is 300 kN and there are two wheels on one side, what transverse crane force does IS 875 (Part 2) give on that rail and per wheel?

A 15 kN total and 7.5 kN per wheel B 30 kN total and 15 kN per wheel C 45 kN total and 22.5 kN per wheel D 60 kN total and 30 kN per wheel

Question 9 ప్రశ్న 9

The sum of all static wheel loads of an overhead crane is 500 kN. What horizontal traction force along the rails is specified by IS 875 (Part 2)?

A 10 kN B 20 kN C 25 kN D 50 kN

Question 10 ప్రశ్న 10

Which statement correctly reflects the IS 875 (Part 2) treatment of horizontal crane-force combinations?

A Either transverse surge or longitudinal traction may act with the vertical crane load; they are generally not assumed simultaneous, but when only one crane is in the bay the lateral and longitudinal forces may act together with the vertical load B Vertical and horizontal crane loads are never considered together C Transverse surge and longitudinal traction must always act simultaneously for every multi-crane bay D Only longitudinal traction is combined with vertical wheel loads

Question 11 ప్రశ్న 11

Why is influence-line or equivalent moving-load reasoning important when determining design actions in a simply supported gantry girder?

A Because the wheel system moves and the position producing maximum reaction, shear or bending moment is not necessarily the same for every response quantity B Because a gantry girder carries only uniformly distributed load C Because moving wheel loads produce no bending moment D Because crane-wheel spacing has no influence on girder actions

Question 12 ప్రశ్న 12

A simply supported 8 m gantry girder carries two static wheel loads of 120 kN each at 2 m and 5 m from the left support. Ignoring girder self-weight, what are the left reaction and the maximum bending moment for this specified wheel position?

A 105 kN and 270 kN·m B 120 kN and 300 kN·m C 135 kN and 315 kN·m D 150 kN and 360 kN·m

Question 13 ప్రశ్న 13

The two 120 kN wheel loads in the previous question are from an electric overhead crane and are to be increased by 25 percent for vertical impact. For the same wheel positions, what maximum bending moment results from the wheel loads?

A 315.0 kN·m B 337.5 kN·m C 378.0 kN·m D 393.75 kN·m

Question 14 ప్రశ్న 14

For a conventional gantry girder with a vertical web, which statement best describes the principal bending effects of crane loading?

A Vertical wheel loads mainly produce major-axis bending, while transverse crane forces at rail level can produce minor-axis lateral bending B Vertical wheel loads produce only minor-axis bending and transverse loads produce no bending C Both vertical and transverse loads always act about exactly the same principal axis D Only axial compression is produced in the gantry girder

Question 15 ప్రశ్న 15

A transverse crane force of 15 kN acts at rail level 0.40 m above the shear centre of a gantry-girder section. What torsional moment about the longitudinal axis is introduced solely by this vertical eccentricity?

A 3 kN·m B 6 kN·m C 15 kN·m D 37.5 kN·m

Question 16 ప్రశ్న 16

A gantry-girder section has Ix = 900 × 10^6 mm^4 with ymax = 300 mm, and Iy = 120 × 10^6 mm^4 with xmax = 150 mm. What are the elastic section moduli Zx and Zy?

A Zx = 1.5 × 10^6 mm^3 and Zy = 0.4 × 10^6 mm^3 B Zx = 3.0 × 10^6 mm^3 and Zy = 0.8 × 10^6 mm^3 C Zx = 4.5 × 10^6 mm^3 and Zy = 1.2 × 10^6 mm^3 D Zx = 6.0 × 10^6 mm^3 and Zy = 1.6 × 10^6 mm^3

Question 17 ప్రశ్న 17

For the section in the previous question, a load case produces Mx = 450 kN·m and My = 40 kN·m. Using elastic principal-axis stress superposition, what normal stress magnitude occurs at a corner where the two bending stresses have the same sign?

A 100 MPa B 150 MPa C 175 MPa D 200 MPa

Question 18 ప్రశ్న 18

If a built-up gantry-girder cross-section is unsymmetrical and a load acts in a non-principal plane, what is the appropriate structural-analysis approach?

A Determine the principal axes and resolve the loading or moments appropriately, then consider the combined principal-axis bending effects B Assume the geometric horizontal and vertical axes are always principal axes C Ignore the smaller bending component regardless of its magnitude D Treat every non-principal load as pure axial force

Question 19 ప్రశ్న 19

As a preliminary elastic section-property check, a gantry girder must carry a major-axis bending moment of 500 kN·m while limiting the corresponding elastic bending stress to 200 MPa. What minimum elastic section modulus Zx is required?

A 1.25 × 10^6 mm^3 B 2.00 × 10^6 mm^3 C 2.50 × 10^6 mm^3 D 4.00 × 10^6 mm^3

Question 20 ప్రశ్న 20

Why is a channel or other additional element sometimes connected to the top of a rolled I-section used as a gantry girder?

A It can improve lateral stiffness and minor-axis section properties near the rail level when adequately connected to participate in the built-up section B It eliminates every need for web checks and fatigue assessment C It reduces the minor-axis moment of inertia to zero D It ensures that crane horizontal forces disappear

Question 21 ప్రశ్న 21

According to IS 800:2007 serviceability guidance, what vertical deflection limit applies to a gantry girder carrying an electrically operated crane of capacity up to 50 tonnes?

A Span/300 B Span/500 C Span/750 D Span/1000

Question 22 ప్రశ్న 22

A gantry girder supporting an electrically operated crane of capacity not exceeding 50 tonnes has a span of 7.5 m. Using the IS 800 vertical deflection limit of L/750, what maximum vertical deflection is permitted?

A 5 mm B 7.5 mm C 10 mm D 15 mm

Question 23 ప్రశ్న 23

Why must the web of a gantry girder be checked locally beneath crane-wheel loads even when the girder has adequate overall bending and shear strength?

A Concentrated wheel loads can cause local web bearing, yielding, buckling or crippling near the loaded flange B Wheel loads affect only the tension flange and never the web C Local web behaviour occurs only in reinforced concrete beams D Adequate global bending strength automatically makes every local web check unnecessary

Question 24 ప్రశ్న 24

Why can fatigue be an important design consideration for a gantry girder even when the maximum static strength check is satisfactory?

A Repeated crane passages create fluctuating stress cycles, and fatigue-sensitive details such as welds, attachments and abrupt stress concentrations can accumulate damage B Fatigue occurs only in concrete and never in structural steel C Crane girders experience only one load cycle during their service life D Increasing static yield strength automatically eliminates fatigue in every connection detail

Question 25 ప్రశ్న 25

Which sequence best represents a sound Degree-Level design approach for selecting and checking a steel gantry girder?

A Determine static crane-wheel reactions and applicable dynamic and horizontal forces, position moving loads for critical effects, select a trial section, then check major- and minor-axis actions, shear, stability, local web effects, serviceability, fatigue where applicable and connections B Select the lightest beam from a table and ignore the crane wheel arrangement C Check only the vertical bending moment and disregard all horizontal crane forces D Design the rail alone because the supporting girder does not participate structurally

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