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Correct choice is (d) about two to three TIMES the average stress on the net area

The best explanation: From the theory of elasticity, the tensile stress adjacent to HOLE will be about two to three times the average stress on the net area, depending upon the ratio of diameter of hole to the width of plate normal to DIRECTION of stress.

Correct answer is (b) rupture of member when the cross section reaches ultimate stress

The best I can explain: The point adjacent to hole reaches yield stress FIRST when tension member with hole is loaded statically. The stress at that point remains CONSTANT and each fibre AWAY from hole progressively reaches yield stress on further loading. With increasing LOAD, deformations continue until finally rupture of member occurs when ENTIRE net cross section of member reaches ultimate stress.

The correct option is (a) considerable deformation of the member in longitudinal direction MAY take place before it fractures, making the structure UNSERVICEABLE

Explanation: Tension member without bolt HOLES can resist LOADS up to ultimate load without failure. But such a member will deform in longitudinal direction considerably(10-15% of its ORIGINAL length)before fracture and the structure becomes unserviceable.

Right choice is (c) PL/EAg

The best EXPLANATION: The displacement, that is increase in length of tension MEMBER, under service load is given by Δ = PL/EAg, where Δ = Elongation of member in mm, P= unfactored axial load in N, L = length of member in mm, E = elastic modulus = 2×10^5MPa, AG = GROSS cross sectional AREA of member in mm^2.

The correct answer is (a) 400

To elaborate: The maximum effective SLENDERNESS RATIO for members always in tension other than pre-tensioned members is 400.

Correct OPTION is (a) applicable to cables

To elaborate: The LIMITS SPECIFIED for SLENDERNESS ratio in the IS code are not applicable to cables. They are applicable to angle sections, built-up sections, circular sections.

Right option is (c) 350

Explanation: The maximum effective slenderness ratio for a MEMBER NORMALLY acting as a tie in roof TRUSS or a bracing member, which is not considered when subject to stress reversal resulting from action of wind or EARTHQUAKE forces is 350.

Correct option is (d) 250

To EXPLAIN: The maximum EFFECTIVE slenderness RATIO for a member subjected to compressive forces resulting only from combination of wind or earthquake actions, such that the deformation of such member does not adversely AFFECT stresses in any part of STRUCTURE is 250.

Right choice is (a) 180

The best explanation: The MAXIMUM EFFECTIVE slenderness RATIO for a tension member in which stress reversal OCCURS due to LOADS other than wind or seismic forces is 180.

Right option is (b) ratio of its unsupported LENGTH to its least radius of gyration

The EXPLANATION is: Slenderness ratio of tension member is ratio of its unsupported length to its least radius of gyration. This LIMITING slenderness ratio is REQUIRED in ORDER to prevent undesirable lateral movement or excessive vibration.

The CORRECT answer is (c) Built up members can be made SUFFICIENTLY stiff

The best explanation: Built-up members, made up of two or more plates or shapes and connected to act as single member, are formed primarily to meet required area which cannot be provided by single ROLLED section. Built up members are more rigid because for same area much greater moment of inertia can be obtained than single rolled section. Built up members can be made sufficiently stiff to carry COMPRESSION and tension thus desirable when STRESS reversal occurs.

The correct choice is (a) ANGLES placed on same side of GUSSET plate PRODUCE eccentricity about one plane only

To elaborate: TWO angle SECTIONS can either be placed back-to-back on the same side of gusset plate, or back-to-back on the opposite side of gusset plate. When angles are connected on the same side of gusset plate, the eccentricity is about one plane only, which can be almost eliminated when the same angles are connected on opposite side of gusset plate.

Right answer is (c) flat bars are used instead of angles in case of stress reversal

The best EXPLANATION: For light loads, angles are preferred over flat bars. In many light BRIDGES, flat bar tension MEMBERS tend to vibrate during passage of load. In case of stress reversal angles are more suitable whereas flat bars are unfit to carry compressive load on reversal due to their SMALL radius of gyration in one direction.

The correct answer is (b) flat bars

Explanation: Tension members were generally made of flat bars earlier. But modern practice is to use MAINLY the FOLLOWING sections for tension members: (i)OPEN sections such as angles, channels and I-sections, (ii)compound and built up sections such as double angle and double channels with or WITHOUT additional plates, (iii)closed sections such as circular, square, rectangular or HOLLOW sections.

The correct choice is (c) fabricating rod/bar short of its required THEORETICAL length

Explanation: Sagging of members by built up BARS and rods may be minimised by limiting length DIAMETER or THICKNESS ratio or by fabricating the rod/bar short of its required theoretical length by some arbitrary amount and drawing into place to provide an initial TENSION. The same effect may be produced by providing turnbuckle in the rod.

Correct CHOICE is (d) They are recommended in BRACING systems

To explain I would say: CABLES used as floor suspenders in suspension bridges are MADE from individual strands wound together in rope like fashion. Cables in form of wires ropes and strands are used in application where high strength is required and flexural RIGIDITY is unimportant. Cables are generally long and their flexural rigidity is negligible. They are flexible. They are not recommended in bracing systems as they cannot resist compression.

Correct option is (a) single angle section with BOLTED connection produce eccentricity about both planes

Easy EXPLANATION: Single angle section with bolted connection produce eccentricity about both planes, whereas single angle section with welded connection may produce eccentricity about ONE PLANE only.

Correct answer is (d) length of plate

Easiest explanation: The strength of tensile members is influenced by factors such as length of connection, size and spacing of FASTENERS, size and spacing of fasteners, NET area of CROSS section, type of fabrication, connection eccentricity, and shear lag at the END connection.

Right OPTION is (b) STRUCTURAL elements that are subjected to direct tensile loads

For explanation: Steel tension members are those structural elements that are subjected to direct axial tensile loads, which tend to ELONGATE the members. A member in PURE tension can be stressed up to and beyond the yield limit and does not buckle LOCALLY or overall.