Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
Which statement most accurately describes the Indian design context for a structural-steel railway bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Railway bridges are subjected to specialized traffic actions and operational requirements that differ from ordinary building structures. Indian Railways therefore uses its Bridge Rules and Steel Bridge Code together with applicable specifications and instructions. The Indian Railways Bridge Manual provides current railway guidance on bridge terminology, inspection and maintenance. General structural mechanics remain applicable, but railway-specific loading and detailing requirements cannot simply be replaced by building provisions. Therefore Option A is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which statement best distinguishes a plate-girder railway bridge from an open-web or lattice-girder railway bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A steel plate girder behaves essentially as a deep fabricated beam having flanges connected by a relatively thin continuous web plate. The flanges provide a major part of the bending resistance and the web provides a major part of the shear resistance. An open-web or lattice girder instead replaces the continuous web by a triangulated system of diagonal and vertical members. Its chords and web members therefore carry predominantly axial forces under ideal truss action. Therefore Option A is correct.
వివరణ:
Question 3
ప్రశ్న 3
Which description corresponds to a deck plate-girder railway bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
In a deck-type bridge, the traffic deck or track is located above the principal load-carrying girders. Indian Railways bridge terminology includes deck plate girders with the permanent way carried over the main girders. This arrangement differs from a through or half-through system in which the principal girders rise alongside the track. The choice affects structural depth below rail level, bracing arrangement and load-transfer detailing. Therefore Option A is correct.
వివరణ:
Question 4
ప్రశ్న 4
Which statement correctly describes a half-through plate-girder railway bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
In a half-through plate-girder arrangement, the main girders are located on the sides of the track and extend above the level of the floor system. The track may be supported through cross girders and stringers or another suitable floor arrangement. Unlike a fully through open-web truss, a plate-girder arrangement normally does not provide an overhead triangulated truss between deep top chords. The terminology therefore refers primarily to the relative position of the deck and the main girders. Therefore Option A is correct.
వివరణ:
Question 5
ప్రశ్న 5
Which statement best describes a through triangulated or open-web railway bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
In a through triangulated bridge, the main open-web girders or trusses are positioned on the sides of the railway track. The floor system carrying the track is generally located near the level of the lower chords. Cross girders transfer loads from the floor system into the main trusses at panel points. Through configurations can also use overhead bracing between the main trusses to provide lateral stability. Therefore Option A is correct.
వివరణ:
Question 6
ప్రశ్న 6
Which sequence most accurately represents the vertical load path in a typical through railway truss bridge having stringers and cross girders?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The permanent way and train loads are first introduced through the rails and sleepers or the corresponding track-support system. Longitudinal stringers support the track between successive cross girders. Cross girders then transmit their end reactions to the main trusses or girders. The main bridge girders carry these forces to the support bearings, which transfer them to piers or abutments. Therefore Option A is correct.
వివరణ:
Question 7
ప్రశ్న 7
What is the principal structural function of a stringer in the floor system of a through railway bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A stringer, also called a rail bearer in many railway bridge descriptions, runs generally parallel to the track and main bridge girders. It spans from one cross girder to the next. The track loads acting over its tributary portion are therefore converted into reactions at the cross girders. It must be designed for the bending, shear, dynamic effects and connection forces appropriate to its loading. Therefore Option A is correct.
వివరణ:
Question 8
ప్రశ్న 8
What is the principal structural function of a cross girder in a through open-web railway bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Cross girders, or floor beams, extend transversely between the two main bridge girders. Stringers commonly frame into them and deliver concentrated reactions from the track-supporting floor system. Their end reactions are then transmitted into the main trusses or girders. Locating this transfer at panel points is particularly desirable for an ideal truss because it avoids unnecessary bending in chord members. Therefore Option A is correct.
వివరణ:
Question 9
ప్రశ్న 9
Why is it structurally desirable to introduce cross-girder reactions into the main truss at panel points?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Ideal truss analysis assumes that external forces are applied at the joints where member centrelines intersect. Under this condition, the individual truss members behave predominantly as two-force members. Applying a substantial floor-beam load between panel points would introduce local bending into the chord in addition to its axial force. Introducing cross-girder forces at panel points therefore preserves efficient triangulated action. Therefore Option A is correct.
వివరణ:
Question 10
ప్రశ్న 10
Under ordinary downward gravity loading on a simply supported parallel-chord railway truss, which general chord-force pattern is expected?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A simply supported truss under downward gravity loads has a global bending action analogous to that of a simply supported beam. The upper part of the structural system is associated primarily with the compression side of this bending action. The lower chord therefore acts principally as the tension chord. The exact chord force varies from panel to panel and additional load cases can alter the force pattern. Therefore Option A is correct.
వివరణ:
Question 11
ప్రశ్న 11
Which statement is correct regarding diagonal and vertical members in a lattice or truss railway girder?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The truss web transfers the equivalent shear between the upper and lower chords. Whether a particular diagonal or vertical carries tension or compression depends on the chosen truss geometry and the direction of panel shear. Moving railway loading can also alter the force magnitude and, in some arrangements, its sign. Member design must therefore use the governing force obtained from analysis rather than a universal assumption based only on appearance. Therefore Option A is correct.
వివరణ:
Question 12
ప్రశ్న 12
A simply supported railway-bridge stringer spans 4 m between cross girders and is subjected to an equivalent uniformly distributed load of 30 kN/m for a specified load case. What are its maximum bending moment and support reaction?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For a simply supported member carrying a full-span uniformly distributed load, the maximum bending moment is wL squared divided by eight. Here this gives 30 × 4 squared / 8 = 60 kN·m. Each support reaction is wL/2, which is 30 × 4/2 = 60 kN. These reactions would be transferred from the stringer into its supporting cross girders. Therefore Option B is correct.
వివరణ:
Question 13
ప్రశ్న 13
A simply supported cross girder of span 5 m carries two equal stringer reactions of 120 kN at 1 m and 4 m from the left support. Neglecting its self-weight, what are the support reactions and the maximum bending moment?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The loading is symmetrical about the centre of the cross girder. The total applied load is 240 kN, so each support reaction is 120 kN. Between the two point loads the shear force is zero, and the bending moment is therefore constant over that region. Its value is 120 × 1 = 120 kN·m. Therefore Option A is correct.
వివరణ:
Question 14
ప్రశ్న 14
A cross girder transfers a total vertical floor-system load of 400 kN symmetrically to two main trusses. Neglecting the cross girder's own weight, what vertical panel-point load is delivered to each main truss?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The cross girder is assumed symmetrically supported by the two main trusses. Under symmetric loading its end reactions are equal. The total applied vertical force of 400 kN must therefore be divided equally between the two ends. Each main girder receives a 200 kN panel-point reaction. Therefore Option B is correct.
వివరణ:
Question 15
ప్రశ్న 15
At a section of a parallel-chord truss bridge, the global bending moment is approximately 6000 kN·m and the distance between the chord centrelines is 6 m. Using the simple chord-couple approximation F = M/h, what chord-force magnitude is indicated?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A useful preliminary interpretation of a parallel-chord truss is to represent the global bending moment by a couple formed by the two chord forces. The magnitude of each force in this idealization is approximately M divided by the distance between the chord resultants. Thus F = 6000/6 = 1000 kN. Detailed truss analysis is still required to obtain actual panel forces and account for the complete loading. Therefore Option C is correct.
వివరణ:
Question 16
ప్రశ్న 16
What are the basic structural functions of a bridge bearing?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Bearings form the mechanical interface between the bridge superstructure and its supporting piers or abutments. They transfer vertical reactions and, where required by their configuration, horizontal forces. At the same time they provide the rotational and translational degrees of freedom assumed in structural analysis. Correct bearing behaviour prevents unintended restraint forces from being introduced into the superstructure or substructure. Therefore Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
In the usual structural idealization of a simply supported bridge, what movement is associated with a fixed or hinged bearing?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A fixed bridge bearing does not imply that the girder end is rotationally fixed in the beam-theory sense. Its usual role is to define the longitudinal reference point of the span by restraining translation. Rotation associated with girder deflection is nevertheless permitted. The bearing can consequently transfer the appropriate horizontal action while avoiding an unintended fixed-ended bending condition. Therefore Option A is correct.
వివరణ:
Question 18
ప్రశ్న 18
What movement is associated with an expansion or free bearing in the longitudinal direction of a simply supported bridge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A bridge span changes length because of temperature variation and can also experience movement from other structural effects. The expansion bearing accommodates the required longitudinal displacement rather than fully restraining it. It must at the same time transmit the vertical support reaction to the substructure. Rotation of the girder end is also accommodated by an appropriate bearing mechanism. Therefore Option A is correct.
వివరణ:
Question 19
ప్రశ్న 19
Which statement correctly distinguishes the traditional rocker and rocker-and-roller bearing arrangements used on steel railway bridges?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Traditional open-web railway girders have commonly used a rocker arrangement at the fixed end and a rocker-and-roller arrangement at the expansion end. The rocker mechanism accommodates the rotation of the girder at the support. Rollers at the free end additionally permit longitudinal displacement resulting from expansion and contraction. The fixed rocker end establishes the longitudinal reference and transmits the appropriate longitudinal force. Therefore Option A is correct.
వివరణ:
Question 20
ప్రశ్న 20
A steel bridge span is 45 m long. Taking the coefficient of thermal expansion as 12 × 10^-6 per degree Celsius, what change in length occurs for a uniform temperature rise of 40 degrees Celsius if expansion is unrestrained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Thermal movement is calculated from delta L = alpha L delta T. The span length is 45000 mm and the temperature change is 40 degrees Celsius. Thus delta L = 12 × 10^-6 × 45000 × 40 = 21.6 mm. An expansion bearing and the associated clearances must be capable of accommodating the movement required by the design temperature range. Therefore Option C is correct.
వివరణ:
Question 21
ప్రశ్న 21
Why is a simply supported bridge span commonly provided with one longitudinally fixed bearing arrangement and one expansion bearing arrangement?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A simply supported span needs sufficient restraint to maintain its position and transfer the horizontal actions assigned to the fixed support. It also needs freedom to expand and contract as temperature changes. Providing an expansion end avoids developing large unintended restraint forces from ordinary thermal length changes. Both ends still transmit their appropriate vertical reactions. Therefore Option A is correct.
వివరణ:
Question 22
ప్రశ్న 22
A simply supported railway bridge transmits a total vertical load of 2400 kN symmetrically to its two end supports. Neglecting all other effects, what vertical reaction is carried by each support bearing?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The total vertical force acting on the span is 2400 kN. With symmetric loading and symmetric end supports, the two vertical reactions are equal. Vertical equilibrium therefore gives each reaction as 2400/2 = 1200 kN. The bearing must be capable of transferring this reaction together with any other forces assigned to it by the design. Therefore Option B is correct.
వివరణ:
Question 23
ప్రశ్న 23
A simply supported bridge span is 30 m long. A single 600 kN vertical load acts 12 m from the left bearing. Neglecting all other loads, what are the left and right bearing reactions respectively?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Taking moments about the left support gives the right reaction as 600 × 12/30 = 240 kN. Vertical equilibrium then gives the left reaction as 600 - 240 = 360 kN. The support closer to the load consequently carries the larger reaction. Moving railway loads require repeated positioning to establish the governing bearing reactions in actual bridge design. Therefore Option C is correct.
వివరణ:
Question 24
ప్రశ్న 24
A bearing transmits a vertical reaction of 1200 kN uniformly over an effective contact area 500 mm × 300 mm. What average compressive bearing pressure results?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The effective contact area is 500 × 300 = 150000 mm^2. The vertical reaction is 1200 kN, or 1,200,000 N. The average pressure is therefore 1,200,000/150000 = 8 N/mm^2. This is a basic pressure calculation only, and an actual bearing design must compare the relevant contact stresses with the applicable material and railway bearing requirements. Therefore Option C is correct.
వివరణ:
Question 25
ప్రశ్న 25
What is a likely structural consequence if an expansion bearing on a railway bridge becomes seized and can no longer accommodate the longitudinal movement assumed in design?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
An expansion bearing is introduced specifically to allow the relative translation assumed in the structural system. If corrosion, debris or mechanical damage prevents this movement, thermal expansion and contraction become partially restrained. This can create additional longitudinal forces and stresses that were not intended in the nominal simply supported model. Bearing inspection and maintenance are therefore structural-safety activities rather than merely cosmetic maintenance. Therefore Option A is correct.
వివరణ:
Question 26
ప్రశ్న 26
Which statement correctly describes the movement mechanisms of some modern bridge bearings compared with traditional rocker-and-roller bearings?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Bridge bearings can provide the required degrees of freedom through several different physical mechanisms. In an elastomeric bearing, longitudinal movement can be accommodated through shear deformation of the elastomer and rotation through differential compression. PTFE combined with a suitable sliding surface provides a low-friction mechanism for translational movement in bearings designed for that purpose. Traditional rocker and roller bearings achieve comparable structural freedoms through mechanical rocking and rolling rather than deformation or sliding materials. Therefore Option A is correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
-
Question 1 ప్రశ్న 1Answer: A. Railway-specific bridge actions and requirements are governed by the applicable IRS Bridge Rules and IRS Steel Bridge Code, together with relevant current railway specifications and manuals సమాధానం: A.
-
Question 2 ప్రశ్న 2Answer: A. A plate girder has a substantially continuous web joining its flanges, whereas an open-web or lattice girder uses triangulated chord and web members సమాధానం: A.
-
Question 3 ప్రశ్న 3Answer: A. The track is carried above the main plate girders, commonly with the permanent way supported at or over their top-flange level సమాధానం: A.
-
Question 4 ప్రశ్న 4Answer: A. The track is carried on a floor system between the main plate girders, which rise above the track or floor level సమాధానం: A.
-
Question 5 ప్రశ్న 5Answer: A. The railway track is carried through the space between the main trusses, commonly on a floor system near the bottom-chord level, with overhead bracing where provided by the through configuration సమాధానం: A.
-
Question 6 ప్రశ్న 6Answer: A. Rails and sleepers → stringers → cross girders → main trusses → bearings → substructure సమాధానం: A.
-
Question 7 ప్రశ్న 7Answer: A. It spans longitudinally between cross girders and transfers track loads to those cross girders సమాధానం: A.
-
Question 8 ప్రశ్న 8Answer: A. It spans transversely between the main girders and transfers stringer or floor-system reactions to the main girders at or near panel points సమాధానం: A.
-
Question 9 ప్రశ్న 9Answer: A. It allows the main truss members to behave predominantly as axial-force members under the usual idealized truss model సమాధానం: A.
-
Question 10 ప్రశ్న 10Answer: A. Top chord predominantly in compression and bottom chord predominantly in tension సమాధానం: A.
-
Question 11 ప్రశ్న 11Answer: A. Their force may be tensile or compressive depending on truss configuration, panel location and loading సమాధానం: A.
-
Question 12 ప్రశ్న 12Answer: B. 60 kN·m and 60 kN సమాధానం: B.
-
Question 13 ప్రశ్న 13Answer: A. 120 kN at each support and 120 kN·m maximum moment సమాధానం: A.
-
Question 14 ప్రశ్న 14Answer: B. 200 kN సమాధానం: B.
-
Question 15 ప్రశ్న 15Answer: C. 1000 kN సమాధానం: C.
-
Question 16 ప్రశ్న 16Answer: A. To transfer support reactions to the substructure while permitting or restraining translation and rotation in accordance with the structural design సమాధానం: A.
-
Question 17 ప్రశ్న 17Answer: A. Rotation is permitted while longitudinal translation at that support is restrained సమాధానం: A.
-
Question 18 ప్రశ్న 18Answer: A. It permits the required longitudinal translation as well as rotation while continuing to transmit vertical reaction సమాధానం: A.
-
Question 19 ప్రశ్న 19Answer: A. The rocker-and-roller end permits longitudinal translation and rotation, while the rocker fixed end permits rotation but restrains longitudinal translation సమాధానం: A.
-
Question 20 ప్రశ్న 20Answer: C. 21.6 mm సమాధానం: C.
-
Question 21 ప్రశ్న 21Answer: A. The fixed bearing establishes the longitudinal reference and transfers appropriate horizontal forces, while the expansion end allows length changes without unnecessarily restraining the span సమాధానం: A.
-
Question 22 ప్రశ్న 22Answer: B. 1200 kN సమాధానం: B.
-
Question 23 ప్రశ్న 23Answer: C. 360 kN and 240 kN సమాధానం: C.
-
Question 24 ప్రశ్న 24Answer: C. 8 N/mm^2 సమాధానం: C.
-
Question 25 ప్రశ్న 25Answer: A. Thermal and other imposed movements can generate unintended restraint forces in the girder, bearing and substructure సమాధానం: A.
-
Question 26 ప్రశ్న 26Answer: A. Elastomeric bearings can accommodate translation by shear deformation and rotation by differential compression, while PTFE sliding interfaces can be used where low-friction translational movement is required సమాధానం: A.