Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
Which statement correctly describes the current design-code context for compound and built-up structural steel beams in India?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 800:2007 remains the currently published general structural-steel design code. Its provisions include classification and design considerations applicable to built-up and compound steel elements. Such beams must satisfy the relevant strength, stability and serviceability requirements just as other steel members do. The fact that a section is fabricated from multiple components does not remove it from the Limit State design framework. Therefore Option A is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which standard is primarily used for dimensions and tabulated sectional properties of standard hot-rolled beams, columns, channels and angles that may form parts of a compound beam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 808:2021 gives dimensions and sectional properties for standard hot-rolled beam, column, channel and angle sections. These properties are useful when a rolled section is used alone or becomes one component of a compound section. Properties such as area, moment of inertia and radius of gyration can be combined to obtain those of the complete built-up section. IS 800 supplies the structural-design rules rather than replacing these dimensional tables. Therefore Option A is correct.
వివరణ:
Question 3
ప్రశ్న 3
In conventional steel-design terminology, which arrangement is a typical example of a compound beam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A compound beam commonly consists of a rolled steel beam strengthened by additional steel components such as cover plates. The added material is usually placed where it efficiently increases the required section property. The connections between the original section and the added components must transmit the interface forces required for common action. Once adequately connected, the assembly is analysed as a built-up structural section subject to the applicable design checks. Therefore Option A is correct.
వివరణ:
Question 4
ప్రశ్న 4
Which statement best distinguishes a general built-up beam from a conventional plate girder?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Built-up beam is a broad term for a beam assembled from multiple steel components that are connected to act together. Examples include paired rolled sections and rolled beams strengthened with cover plates. A plate girder is a more specific fabricated I-girder arrangement using separate flange and web plates. Deep or slender plate-girder webs can introduce additional buckling and stiffener design issues that need not govern an ordinary compound rolled beam. Therefore Option B is correct.
వివరణ:
Question 5
ప్రశ్న 5
For an ordinary built-up I-shaped steel beam subjected mainly to major-axis bending and vertical shear, which statement most accurately describes the roles of the flange and web?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Major-axis bending produces large longitudinal tensile and compressive stresses near the extreme fibres of an I-shaped beam. The flanges are located far from the neutral axis and consequently make a major contribution to bending resistance. Vertical shear stress is concentrated more strongly in the web region. The complete cross-section nevertheless participates according to the actual stress distribution, so this flange-web description is a useful structural interpretation rather than an absolute separation. Therefore Option A is correct.
వివరణ:
Question 6
ప్రశ్న 6
Why are bolts or welds between the components of a compound beam structurally necessary?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The section-property calculation for a built-up beam generally assumes that the components deform together. Bending creates longitudinal force changes that must be transferred between the connected components. Bolts or welds provide this force transfer and limit relative slip at their interface. If the connection is inadequate, the assembly cannot safely be credited with the full stiffness and strength calculated for a perfectly connected section. Therefore Option B is correct.
వివరణ:
Question 7
ప్రశ్న 7
A doubly symmetric rolled I-section 400 mm deep is strengthened by identical 200 mm × 12 mm cover plates placed centrally on both the top and bottom flanges. Where is the centroid of the strengthened section relative to the original centroid?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The original rolled section is symmetric about its horizontal centroidal axis. Identical cover plates are added at equal distances above and below that axis. Their first moments of area therefore cancel one another. The horizontal centroidal axis consequently remains at the original mid-depth location even though the total depth and moment of inertia increase. Therefore Option A is correct.
వివరణ:
Question 8
ప్రశ్న 8
A symmetric rolled beam has Ix = 300 × 10^6 mm^4 and overall depth 400 mm. Identical 200 mm × 12 mm cover plates are added to its top and bottom faces. Neglecting any gaps, what is the new Ix approximately?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Each cover plate has area 200 × 12 = 2400 mm^2 and its centroid is 206 mm from the common neutral axis. Its own centroidal inertia is 200 × 12^3/12 = 28800 mm^4. Using the parallel-axis theorem, the two plates add 2[28800 + 2400(206)^2] mm^4 to the original inertia. The resulting Ix is approximately 503.75 × 10^6 mm^4. Therefore Option C is correct.
వివరణ:
Question 9
ప్రశ్న 9
For the strengthened section in the previous question, the new overall depth is 424 mm and Ix = 503.75 × 10^6 mm^4. What is the elastic section modulus about the major axis?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The extreme fibre of the symmetric strengthened section is 424/2 = 212 mm from the neutral axis. Elastic section modulus is Ze = I/ymax. Thus Ze = 503.75 × 10^6/212 = approximately 2.376 × 10^6 mm^3. This larger section modulus demonstrates why cover plates placed far from the neutral axis can efficiently increase bending resistance. Therefore Option C is correct.
వివరణ:
Question 10
ప్రశ్న 10
The built-up section in the previous question has Ze = 2.376 × 10^6 mm^3 and is subjected to an elastic major-axis moment of 400 kN·m. What extreme-fibre bending stress is produced?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Elastic extreme-fibre stress is obtained from sigma = M/Ze. The bending moment is 400 × 10^6 N·mm. Dividing this by 2.376 × 10^6 mm^3 gives approximately 168.4 N/mm^2. This calculation assumes the connected components act together so that the stated built-up section modulus is valid. Therefore Option C is correct.
వివరణ:
Question 11
ప్రశ్న 11
Assume the strengthened beam section has been classified as semi-compact, is laterally supported, is under low shear, and has Ze = 2.376 × 10^6 mm^3, fy = 250 MPa and gamma_m0 = 1.10. What design bending strength is obtained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For a semi-compact section under the stated conditions, the bending strength is based essentially on Ze fy/gamma_m0. Substitution gives 2.376 × 10^6 × 250/1.10 N·mm. This equals approximately 540 × 10^6 N·mm. The resulting design bending strength is therefore about 540 kN·m, subject to all other applicable beam checks. Therefore Option C is correct.
వివరణ:
Question 12
ప్రశ్న 12
A rolled beam having Ix = 300 × 10^6 mm^4 deflects 20 mm under a specified elastic loading. After adding fully effective symmetric cover plates, Ix becomes 503.75 × 10^6 mm^4 while E, loading, span and support conditions remain unchanged. What is the new deflection approximately?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For the same elastic beam loading and geometry, deflection is inversely proportional to EI. Young's modulus is unchanged because both sections are structural steel, so the deflection ratio is governed by the ratio of moments of inertia. The new deflection is 20 × 300/503.75 = approximately 11.9 mm. The cover plates therefore increase both strength-related section properties and flexural stiffness. Therefore Option B is correct.
వివరణ:
Question 13
ప్రశ్న 13
Two steel beam components are connected so that they have the same curvature and are made from the same grade of steel. Their major-axis moments of inertia are 300 × 10^6 mm^4 and 200 × 10^6 mm^4. If the total bending moment is 500 kN·m, how is it shared in the ideal elastic built-up action?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Components that undergo the same curvature develop moments in proportion to their flexural stiffness EI. Because the two components have the same Young's modulus, their moment shares are proportional to their respective I values. The ratio is 300:200, or 3:2. Dividing the 500 kN·m total in that ratio gives 300 kN·m and 200 kN·m. Therefore Option B is correct.
వివరణ:
Question 14
ప్రశ్న 14
Two identical rolled beams are placed side by side with their horizontal centroidal axes at the same level and are adequately connected to act together in vertical bending. If each beam has major-axis inertia Ix = 180 × 10^6 mm^4, what is the combined major-axis inertia?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Both component centroids lie on the same horizontal neutral axis for the stated side-by-side arrangement. There is therefore no vertical parallel-axis contribution to the major-axis inertia. The two component inertias can simply be added about this common horizontal axis. Thus Ix,total = 180 × 10^6 + 180 × 10^6 = 360 × 10^6 mm^4. Therefore Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
Two identical steel components each have area 5000 mm^2 and minor-axis centroidal inertia Iy = 20 × 10^6 mm^4. They are arranged symmetrically so that each centroid is 150 mm from the built-up section's common minor centroidal axis. What is the combined Iy?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The parallel-axis theorem must be used because each component centroid is offset from the common minor axis. For each component, the contribution is 20 × 10^6 + 5000(150)^2 = 132.5 × 10^6 mm^4. There are two identical components, so the total is 265 × 10^6 mm^4. Separating material laterally can therefore produce a substantial increase in minor-axis stiffness. Therefore Option C is correct.
వివరణ:
Question 16
ప్రశ్న 16
Which expression represents the elementary longitudinal shear flow that must be transferred at an interface in an elastic built-up beam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Longitudinal shear flow arises because the bending force carried by a component changes along the beam when the bending moment changes. In elementary elastic beam theory, that interface shear flow is q = VQ/I. Here V is the transverse shear force, Q is the first moment of the relevant component area about the neutral axis, and I is the second moment of area of the complete section. Connectors or welds between components must be capable of transferring this longitudinal interface action. Therefore Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
At a section of a built-up beam, V = 200 kN and I = 800 × 10^6 mm^4. A top cover plate has area 3000 mm^2 with its centroid 210 mm from the neutral axis. Using q = VQ/I, what longitudinal interface shear flow must be transferred?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The first moment of the cover-plate area is Q = Ay = 3000 × 210 = 630000 mm^3. The shear force is 200000 N. Thus q = 200000 × 630000/(800 × 10^6) N/mm. This gives 157.5 N/mm, or 0.1575 kN/mm, which the cover-plate connection must transfer under the stated elastic model. Therefore Option C is correct.
వివరణ:
Question 18
ప్రశ్న 18
A cover plate requires an interface shear transfer of 0.16 kN/mm. Transverse connector lines contain two identical bolts, each having a design capacity of 40 kN for the relevant interface action. Based only on this shear-flow requirement, what maximum longitudinal spacing of connector lines is obtained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The two bolts in one connector line provide a total stated resistance of 2 × 40 = 80 kN. Over a longitudinal spacing s, the shear flow produces a force equal to 0.16s kN. Equating this force to 80 kN gives s = 80/0.16 = 500 mm. Actual detailing may require a smaller spacing because of other code and fabrication requirements not included in this calculation. Therefore Option D is correct.
వివరణ:
Question 19
ప్రశ్న 19
What is the principal analytical consequence if the connection between two nominally built-up beam components permits significant relative slip?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The usual built-up section calculation assumes compatible deformation of the connected components. Significant slip violates this compatibility and changes how force is transferred between the parts. The beam may then be less stiff than the perfectly connected section-property calculation predicts. Connection design is therefore an essential part of achieving the intended built-up action rather than merely an erection detail. Therefore Option A is correct.
వివరణ:
Question 20
ప్రశ్న 20
How should local section classification be approached for compound elements consisting of added plates bolted or welded to an original steel section under IS 800?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 800 contains specific guidance for compound elements in built-up sections. Relevant outstanding portions and internal plate widths between connection lines are checked using the thickness of the plate element concerned. Added plate outstands beyond lines of bolts or welds also require an appropriate width-to-thickness check. As with ordinary sections, an unfavourable compression element can restrict the classification and usable bending resistance of the complete cross-section. Therefore Option B is correct.
వివరణ:
Question 21
ప్రశ్న 21
Which statement about lateral-torsional buckling of a compound beam strengthened with flange plates is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Adding flange material can increase major-axis strength and stiffness substantially. It does not by itself prevent the compression flange from moving laterally or the section from twisting. A laterally unrestrained built-up beam can therefore still be governed by lateral-torsional buckling. The restraint conditions and unrestrained length must be considered independently of the increase in cross-sectional bending resistance. Therefore Option B is correct.
వివరణ:
Question 22
ప్రశ్న 22
A welded built-up I-beam has a clear web depth of 600 mm and web thickness of 8 mm. Taking the effective shear area as Av = d tw = 4800 mm^2, fyw = 250 MPa and gamma_m0 = 1.10, what plastic design shear strength is obtained if shear buckling does not govern?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The stated shear area is 600 × 8 = 4800 mm^2. Plastic design shear strength is Av fyw divided by sqrt(3) gamma_m0. Thus Vd = 4800 × 250/[sqrt(3) × 1.10] N. The result is approximately 629.8 kN, provided the web is not governed by shear buckling or another limiting condition. Therefore Option C is correct.
వివరణ:
Question 23
ప్రశ్న 23
Why should a strengthening cover plate on a beam flange not simply be stopped at the exact section where a simple bending-strength calculation first shows it is no longer required?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The added cover plate carries longitudinal force as part of the strengthened flange. That force cannot disappear instantaneously at the theoretical cutoff section. The connecting bolts or welds need sufficient length to transfer the plate force back into the original beam section. Abrupt termination without adequate force transfer can create an unsafe local connection even when the gross bending calculation appears satisfactory. Therefore Option A is correct.
వివరణ:
Question 24
ప్రశ్న 24
A cover plate in the tension region of a built-up beam is connected using bolt holes. Which statement is correct when evaluating the member?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A bolt hole removes material from the connected tension component. This can reduce the net area available to resist tensile force and may influence the relevant strength limit state. Gross section properties can still be appropriate for stiffness and for other code calculations where deductions are not required. A complete built-up beam design must therefore distinguish the section property used for a particular strength or serviceability check. Therefore Option B is correct.
వివరణ:
Question 25
ప్రశ్న 25
Why is adding flange material far from the neutral axis generally an efficient way of strengthening a beam for major-axis bending?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The parallel-axis theorem gives a component contribution equal to its own centroidal inertia plus A y^2. Material placed at a large distance y from the neutral axis therefore produces a large increase in total moment of inertia. It also tends to increase section modulus and hence bending efficiency. This is why cover plates are ordinarily added to flange regions rather than placing the same area close to the neutral axis when flexural strengthening is the objective. Therefore Option A is correct.
వివరణ:
Question 26
ప్రశ్న 26
Which situation most reasonably favours selection of a compound or built-up beam rather than simply using an available single rolled section?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A single rolled section is usually attractive when it satisfies the design requirements economically and with simple fabrication. A built-up or compound beam becomes useful when standard rolled shapes do not provide suitable capacity, stiffness or geometry. Material can then be added where it is structurally effective, such as in flange regions, or multiple rolled shapes can be combined. The benefits must still be balanced against added fabrication, connection, inspection and erection requirements. Therefore Option B is correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
-
Question 1 ప్రశ్న 1Answer: A. IS 800:2007 provides the current published general steel-design framework, including provisions relevant to built-up sections సమాధానం: A.
-
Question 2 ప్రశ్న 2Answer: A. IS 808:2021 సమాధానం: A.
-
Question 3 ప్రశ్న 3Answer: A. A rolled I-section strengthened by flange cover plates connected so that the components act together సమాధానం: A.
-
Question 4 ప్రశ్న 4Answer: B. A built-up beam may combine rolled sections or reinforcing plates, whereas a plate girder is a particular fabricated girder form comprising flange and web plates and may require plate-girder-specific web provisions సమాధానం: B.
-
Question 5 ప్రశ్న 5Answer: A. The flanges carry a large part of the bending normal forces, while the web carries a major part of the vertical shear సమాధానం: A.
-
Question 6 ప్రశ్న 6Answer: B. To transfer interface forces and restrict relative slip so that the components can develop the assumed built-up action సమాధానం: B.
-
Question 7 ప్రశ్న 7Answer: A. It remains at the original centroid సమాధానం: A.
-
Question 8 ప్రశ్న 8Answer: C. 503.75 × 10^6 mm^4 సమాధానం: C.
-
Question 9 ప్రశ్న 9Answer: C. 2.376 × 10^6 mm^3 సమాధానం: C.
-
Question 10 ప్రశ్న 10Answer: C. 168.4 MPa సమాధానం: C.
-
Question 11 ప్రశ్న 11Answer: C. 540 kN·m సమాధానం: C.
-
Question 12 ప్రశ్న 12Answer: B. 11.9 mm సమాధానం: B.
-
Question 13 ప్రశ్న 13Answer: B. 300 kN·m and 200 kN·m సమాధానం: B.
-
Question 14 ప్రశ్న 14Answer: C. 360 × 10^6 mm^4 సమాధానం: C.
-
Question 15 ప్రశ్న 15Answer: C. 265 × 10^6 mm^4 సమాధానం: C.
-
Question 16 ప్రశ్న 16Answer: A. q = VQ/I సమాధానం: A.
-
Question 17 ప్రశ్న 17Answer: C. 157.5 N/mm సమాధానం: C.
-
Question 18 ప్రశ్న 18Answer: D. 500 mm సమాధానం: D.
-
Question 19 ప్రశ్న 19Answer: A. The full composite moment of inertia may no longer be valid because the components do not develop the assumed common action సమాధానం: A.
-
Question 20 ప్రశ్న 20Answer: B. Relevant outstanding and internal plate widths are checked against their own thicknesses, and the least favourable compression-element classification can govern the section సమాధానం: B.
-
Question 21 ప్రశ్న 21Answer: B. The built-up beam can still require a lateral-torsional buckling check if its compression flange is inadequately restrained సమాధానం: B.
-
Question 22 ప్రశ్న 22Answer: C. 629.8 kN సమాధానం: C.
-
Question 23 ప్రశ్న 23Answer: A. The plate and its connection must develop and transfer the plate force into the original beam over an adequate length సమాధానం: A.
-
Question 24 ప్రశ్న 24Answer: B. The holes can reduce the effective or net tensile area even though gross-section properties may still be relevant for other calculations సమాధానం: B.
-
Question 25 ప్రశ్న 25Answer: A. Its contribution to moment of inertia includes the large parallel-axis term A y^2 సమాధానం: A.
-
Question 26 ప్రశ్న 26Answer: B. When available rolled sections are inadequate or inefficient and additional material can be strategically arranged to obtain the required strength, stiffness or sectional geometry సమాధానం: B.