300+ REAL TIME Prestressed Concrete Structures Objective Questions & Answers 2023

250+ TOP MCQs on Basic Assumptions and Answers

Prestressed Concrete Structures Multiple Choice Questions on “Basic Assumptions”.

1. The analysis of stresses developed in prestressed concrete structural elements is based on how many assumptions?
a) 5
b) 4
c) 3
d) 2

Answer: c
Clarification: The analysis of stresses developed in a prestressed concrete structural elements is based on the following assumptions: Concrete is a homogeneous elastic material, Within the range of working stresses, both concrete and steel behave elastically, notwithstanding the small amount of creep which occurs in both the materials under sustained loading, a plan section remains plain even after bending.

2. The tensile stresses when do not exceed the limit of modulus then change in loading of member results in ___________
a) Change of bending moment
b) Change of stress
c) Change in shear
d) Change in rupture

Answer: b
Clarification: As long as tensile stresses do not exceed the limit of modulus of rupture of concrete (corresponding to the stage of visible cracking of concrete), any change in loading of the member results in a change of stress in the concrete only, the sole function of the prestressing tendon being to impart and maintain the prestress in the concrete.

3. Which conditions are negligible at the stage of visible cracking on concrete?
a) Bending conditions
b) Joint conditions
c) Zone conditions
d) Loading conditions

Answer: d
Clarification: Up to the stage of visible cracking on concrete, the changes in the stress of steel, the loading being negligibly small, are generally not considered in the computations, the phenomenon of stress corrosion in steel is particularly dangerous, as it results in sudden brittle fractures.

4. The stresses due to prestressing are referred as ___________
a) Combined stresses
b) Bending stresses
c) Anchoring stresses
d) Tensioning stresses

Answer: a
Clarification: The stresses due to prestressing alone are generally combined stresses due to the action of direct load and bending resulting from an eccentricity applied load, the stresses in concrete are evaluated by using the well known relationship for combined stresses, this type of attack in alloys is due to the internal metallurgical structure, which is influenced by composition, heat treatment and mechanical processing.

5. Which of the following notations are used for evaluating the relationship for combined stresses?
a) P, E, M, A, I
b) P, σ, M, g, I
c) P, W, M, π, L
d) P, θ, M, Z, L

Answer: a
Clarification: The notations and sign conservations used for the analysis of prestress are
P-Prestressing force, e-eccentricity of prestressing force, m – p × e – moment
A – Cross sectional area of the concrete member, I – second moment of area of section about its centroid.

6. The uniform prestress in a concrete member subjected to concentric prestressing is ___________
a) P/e
b) P/s
c) P/t
d) P/a

Answer: d
Clarification: Uniform prestress in concrete p/a, which is compressive across the depth of the beam and the applied loads, dead loads of the beam include tensile stress towards the soffit and are counterbalanced more effectively by eccentric tendons.

7. In case of eccentric prestressing force the support force F_sup is ___________
a) F_sup = p/a(1+ey_b/i²)
b) F_sup = p/a(1+ey_b/i²)
c) F_sup = p/a
d) F_sup = p/a-e_b

Answer: b
Clarification: The stresses developed at the top and bottom fibers of the beam are obtained by the two relations:
F_inf = (p/a+p_e/z_b) = p/a(1+ey_b/i²), F_sup = (p/a-p_e/z_b) = p/a(1-y_bt/i²).

8. The cross section of beam is combination of ___________
a) Direct stresses and Bending stresses
b) Principal stresses and Shear stresses
c) Anchorage and Tension stresses
d) Flexural and Rigidity stresses

Answer: a

250+ TOP MCQs on Codes of Practice and Answers Quiz

Prestressed Concrete Structures Multiple Choice Questions on “Codes of Practice”.

1. Which one of the following is the Indian standard regarded to the limit state of deflection?
a) IS: 1443-1950
b) IS: 1343-1980
c) IS: 1514-1941
d) IS: 1600-1948

Answer: b
Clarification: It is the general practice in most of the codes to safeguard against excessive deflections under serviceability limit states, either indirectly by prescribing a minimum span to depth ratio for the member or directly by specifying a maximum permissible deflection expressed as a fraction of the span and recommendations of Indian standard code with regard to the limit state of deflections is IS: 1343-1980.

2. The final deflection due to all loads including the efforts of temperature, creep and shrinkage should normally exceed span up to __________
a) Span/250
b) Span/300
c) Span/500
d) Span/800

Answer: a
Clarification: The final deflection due to all loads including the effects of temperature, creep and shrinkage should normally not exceed span/250 is the first recommendations made by IS: 1343-1980 with regard to the limit state of deflection.

3. The deflection including the effects of temperature, creep and shrinkage occurring after the erection should not normally exceed __________
a) Span/400
b) Span/350
c) Span/140
d) Span/100

Answer: b
Clarification: The deflection including the effect of temperature, creep and shrinkage occurring after the erection of partitions and the application of finishes should not normally exceed span/350 whichever is less, creep is directly proportional to the stresses but above this value it increases more rapidly.

4. If the finishes are to be applied to the prestressed concrete members, the total upward deflection should not exceed __________
a) Span/300
b) Span/450
c) Span/150
d) Span/350

Answer: a
Clarification: If finishes are applied to the prestressed concrete members, the total upward deflection should not exceed span/300, unless uniformity of chamber between adjacent units can be ensured, span/350 or 20mm whichever is less for non brittle partitions or finishes.

5. The British code specifies a maximum deflection limit of span which the sag in the member usually become noticeable is?
a) Span /130
b) Span/250
c) Span/200
d) Span/150

Answer: c
Clarification: The British code (BS: 8110-1985) specifies a maximum deflection limit of span/250 beyond which the sag in a member will be usually become noticeable and to prevent damage to non-structural elements, the code recommends that the deflection after the installation of finishes & partitions should not exceed the span/500 or 20mm whichever is less for brittle members.

6. The type of deflection of not supporting and non structural elements of flat roofs is?
a) Large deflection
b) Immediate deflection
c) Small deflection
d) Edge deflection

Answer: c
Clarification: Floors roofs not supporting and not attached to non structural element likely to be damaged by large deflection such deflection is considered as immediate deflection due to the live load, deflection limitations are given as (span/180).

7. The floors not supporting and not attached to non structural elements are damaged by __________
a) Large deflection
b) Column deflection
c) Span deflection
d) Beam deflection

Answer: a
Clarification: Floors not supporting and not attached to non structural element likely to be damaged by large deflections and are carried by immediate deflection due to live load and deflection limitations are given as (span/360).

8. The FIP-1984 limits for total deflection below the level of supports up to __________
a) Span/200 to Span/300
b) Span/150 to Span/250
c) Span/100 to Span/50
d) Span/175 to Span/280

Answer: a
Clarification: The FIP-1984 recommends the following suitable deflection limits for floors, roofs and the other horizontal members in building as total deflection below the level of supports is Span/200 to Span/300.

9. The FIP-1984 limits for deflection that occurs after addition of partitions up to __________
a) Span/200 to Span/300
b) Span/250 to Span/350
c) Span/500 to Span/1000
d) Span/170 to Span/320

Answer: c
Clarification: The FIP-1984 recommends the following suitable deflection limits for floors, roofs and the other horizontal members in building limits for deflection that occurs after addition of partitions up to:
Span/500 to Span/1000.

10. The French code limits the deflection of members carrying masonry and partition walls up to __________
a) Span/600
b) Span/400
c) Span/500
d) Span/700

Answer: c
Clarification: The French code limits the deflection of members carrying masonry and partition walls to span/500, which is the total increase in deflection due to short term and sustained loads over the instantaneous deflection due to self weight.

250+ TOP MCQs on Analysis by Guyon and Magnel and Answers

Prestressed Concrete Structures Assessment Questions on “Analysis by Guyon and Magnel”.

1. The length of beam within which the dispersion of prestressing force takes place is known as ____________
a) Zone of action
b) Zone of transmission
c) Zone of anchorage
d) Zone of tendons
Answer: b
Clarification: The length of beam within which the dispersion of the prestressing force takes place is called as zone of transmission; Guyon has developed design tables for the computation of bursting tension in the end blocks which are based on his earlier mathematical investigations concerning the distribution of stress in end blocks subjected to concentrated loads.

2. The tensile forces developed in the transverse direction to the axis are known as ____________
a) Bursting forces
b) Concentrated forces
c) Reduced forces
d) Tensioned forces
Answer: a
Clarification: The tensile forces developed in the transverse direction to the axis of concentrated force are called as bursting forces; the concept of symmetrical or equivalent prism for eccentric cables and the method of partitioning for the analysis of stresses developed due to multiple cables have been introduced by Guyon.

3. The adjacent surface to the anchor plate is also subjected to ____________
a) Compressive forces
b) Tensile forces
c) Transverse forces
d) Torsion
Answer: b
Clarification: The adjacent surface to the anchor plate is also subjected to tensile force at the end section and these are called as spalling forces, the eccentric forces and multiple cables, the symmetric prism method may be used, this consists of a prism of concrete of side equal to twice the distance of the prestressing force from the nearest free edge.

4. During zone of transmission prestressing force is applied through the anchor plate at ____________
a) End
b) Edge
c) Centre
d) Span
Answer: c
Clarification: The prestressing force p is applied through the anchor plate which is placed at the centre of the end beam during zone of transmission, When the forces are arranged such that the resultant of the stress distribution at a distance equal to the depth of the end block coincides with the line of action of the force then the forces are considered to be evenly distributed.

5. Which are formed due to the horizontal, vertical and shear stresses induced at zone of transmission?
a) Rectangles
b) Parabola
c) Curves
d) Trajectories
Answer: d
Clarification: Due to the horizontal, vertical and shear stresses induced at zone of transmission, trajectories of principle stresses are formed, the line of action of the resultant force is taken as the axis of an equivalent prism of length and depth equal to twice the distance of axis from the free edge or the adjoining equivalent prism.

6. The transmission length is influenced by ____________
a) Height
b) Depth
c) Curves
d) Span
Answer: b
Clarification: The transmission length is influenced by depth of the anchor plate and is taken equal to the depth of beam in general, the transverse stress distribution is computed by using the coefficients under the category of concentrated eccentric force and eccentric shear forces since the coefficients are applicable for forces at interval of one eighth of the prism depth, the end forces have to be replaced by a statically equivalent system of normal and shear forces acting at these regular intervals.

7. The transmission length and bursting forces can be obtained depending on the ratio of ____________
a) Depth of anchorages
b) Depth of tendons
c) Depth of bond
d) Depth of curve
Answer: a
Clarification: Depending on the ratio of depth of anchor plate to the depth of beam, the transmission length and bursting force can be obtained, the position of zero stresses, maximum transverse stress and its magnitude for the forces which are evenly distributed are computed by using the coefficiants under the category of distributed axial forces. According to guyon, the bursting tenson is expressed as, F_bst = 0.3P(1-(y_po/y_o)^0.58, p = anchorage force, y_po/y_o = distribution ratio.

8. In general the transmission length and depth of beam are taken as ____________
a) Unequal
b) Equal
c) Less than 1
d) More than 1
Answer: b
Clarification: Generally, the transmission length is taken as equal to the depth of beam and bursting forces are considered in case of transmission length, when it is not possible to arrange the end forces evenly, Guyon recommended that transverse tensile stresses be investigated along successive resultants, such as resultant of all forces, resultant of smaller groups of forces, lines of action of individual forces.

9. The bursting force with depth of beam d’ and the depth of anchor plate d is given by?
a) 0.3P(1-d’/d)
b) 0.9P(1-d’/d)
c) 0.1P(1-d’/d)
d) 1.30P(1-d’/d)
Answer: a
Clarification: The bursting force with depth of beam d’ and the depth of anchor plate d is given by:
P_b = 0.3P (1-d’/d), the distribution of bursting stress for d’/d = 0.8 and d’/d = 0.5 are given as distance along the transmission line.

10. The d’/d value for 0.42d is?
a) 0.6
b) 0.5
c) 0.8
d) 1.0
Answer: b
Clarification: The distribution of bursting stresses d’/d = 0.8 and for d’/d = 0.5 are shown below:

Prestressed Concrete Structures Assessment Questions,

250+ TOP MCQs on Types of Composite Members and Answers

Prestressed Concrete Structures Multiple Choice Questions on “Types of Composite Members”.

1. The most common type of composite construction consists of _____________
a) I beams
b) T beams
c) L beams
d) U beams
Answer: b
Clarification: The most common type of composite construction consists of a number of precast prestressed inverted T beams placed side by side and connected by a continuous top slab of insitu concrete and this type of construction is widely used in the construction of bridge decks.

2. The dead weight of the deck can be considerably reduced by using ___________
a) Stirrups
b) Foundation
c) Reinforcement
d) Voids
Answer: d
Clarification: The dead weight of the deck can be considerably reduced by using voids or light weight longitudinal cores in the space between the precast prestressed units and this light weight concrete for the cast in situ slab results in reduced dead loads, leading to economy in the overall costs.

3. The spans exceeding 30m for large span composite bridge decks the precast concrete unit consists of ___________
a) J sections
b) K sections
c) T sections
d) Rectangular sections
Answer: c
Clarification: For large span composite bridge decks of spans exceeding 30m, the commonly used precast prestressed concrete units consist of I section unsymmetrical T or box sections and the concrete cast insitu forms the deck slab interconnecting the precast units and typical cross section of bridge deck with different type of precast units are compiled.

4. The precast prestressed I and T beams have been standardized by ___________
a) Cement and concrete association
b) American standard association
c) British standard association
d) Indian standard association
Answer: a
Clarification: The precast prestressed I and T beams have been standardized by the cement and concrete association for use in the construction of bridge decks of span varying from 7 to 36m and standard I and T units are extensively used as highway bridge beams in U.S.A.

5. The use of prestressed concrete tie beams in a reinforced concrete truss reduces ___________
a) Spacing
b) Cross section
c) Curing properties
d) Cost
Answer: b
Clarification: The use of prestressed tie beams in a reinforced concrete truss considerably reduces the cross sectional dimensions of the bottom chord member, which is subjected to high degree of tension in the case of large span trusses.

6. Reinforced and prestressed concrete truss generally used for spans ranging from ___________
a) 18 to 36m
b) 14 to 30m
c) 20 to 30m
d) 11 to 19m
Answer: a
Clarification: Reinforced and prestressed concrete trusses are generally used for spans ranging from 18 to 36m and this form of construction is ideally suited for industrial structures transfer prestressing is also used to develop monolithic action in the lateral direction.

7. The dead load stress developed in the precast prestressed units can be minimized by ___________
a) Wedging
b) Anchoring
c) Propping
d) Tensioning
Answer: c
Clarification: The dead load stress developed in the precast prestressed units can be minimized by Propping them while casting the concrete in situ this method of construction is termed as propped construction and if the precast units are not propped while placing the insitu concrete, stresses are developed in the unit due to self weight of the member and dead weight of the insitu concrete and this method of construction is referred as unpropped construction.

8. What is the main advantage of composite member?
a) Ease of work
b) Decreased workability
c) Increased depth of foundation
d) Decreased depth of foundation
Answer: a
Clarification: The main advantage of composite member is it facilitates the ease of work at the construction site and it is the fast approaching process by utilizing the self supporting precast stems the shuttering can be minimized.

9. The precast double tees are used in ___________
a) Balcony
b) Parking structure
c) Balcony & Parking structure
d) None of the mentioned
Answer: b
Clarification: Precast double tees have been used in partially structures, bridge decks are cast in situ slab, it has long term durability and gives aesthetic flexibility, fire resistance and low maintenance and resists gravity seismic and using loads.

10. The depth variation for L shaped composite beams is ___________
a) 2 to 3 feet
b) 6 to 8 feet
c) 14 to 16 feet
d) 2 to 6 feet
Answer: a
Clarification: In this L section the depth varies from 2 to 3 feet deep, web thickness is usually taken as 16”(0.4m) for the steams of deck sections the ledge provides a bearing surface in which the compacted L beam is subjected to different eccentric loading.

250+ TOP MCQs on Optimisation Techniques and Answers

Prestressed Concrete Structures Multiple Choice Questions on “Optimisation Techniques”.

1. The technique for selecting a new point depends upon _____________
a) Scope of the problem
b) Nature of the problem
c) Range of the problem
d) Analysis of the problem
Answer: b
Clarification: In using the mathematical programming methods the process of optimization begins with an acceptable design point and new point is selected suitability so as to minimize the objective function and the search for another new point is continued is continued from the previous point until the optimum point is reached and there are several well established techniques for selecting a new point and to proceed towards the optimum point, depending upon the nature of the problem, such as linear and non linear programming.

2. In linear programming, the solution is based on _________
a) Tensile properties
b) Strain properties
c) Elementary properties
d) None of the mentioned
Answer: c
Clarification: In a linear programming problem, the objective function and constraints are linear functions of the design variables and the solution is based on the elementary properties of systems of linear equations and the properties of systems proportionally, additivity, divisibility and deterministic features are utilized in the mathematical formulation of the linear programming problem.

3. A linear function in three-dimensional space is a _________
a) Midpoint
b) Plane
c) Laminar
d) Zero
Answer: b
Clarification: A linear function in tree-dimensional space is a plane representing the locus of all design points in n-dimensional space, the surface so defined is a hyper plane and in these cases, the intersections of the constraints give solutions which are the simultaneous solutions of the constraint equations meeting at that point.

4. Linear programming problems can be solved by _________
a) Revised simplex method
b) Termed method
c) Moment derivation method
d) Hollow method
Answer: a
Clarification: Linear programming problems can be conveniently solved by the revised simplex method and the simplex algorithm for solving the general linear programming problem is an iterative procedure which yields an exact optima solution in a finite number of steps.

5. One of the most powerful techniques for solving non linear programming is to transform the _________
a) Data
b) Problems
c) Materials
d) Labour
Answer: b
Clarification: One of the most powerful techniques for solving non linear programming is to transform the problem by some means into a form which permits the application of the simplex algorithm and thus, the simple method turns out to be one of the most powerful computational devices for solving linear as well as non linear programming problems.

6. In non linear programming the boundaries of the contours of the function are _________
a) Parallel line
b) Zig Zag lines
c) Straight lines
d) Trapezoidal lines
Answer: c
Clarification: In non linear programming problems, the objective function and or the constraints are non linear function of the design variables and since the boundaries of the feasible region or the contours of equal values of the merit function are straight lines the optimum solution need not necessarily be at an intersection of the constraints.

7. One of the techniques developed for solution of non linear programming is?
a) Single programming
b) Multilinear propramming
c) Reverse programming
d) Dynamic programming
Answer: d
Clarification: Over the years, several techniques have been developed for the solution of non linear programming problems and some of the prominent techniques are: method of feasible directions, sequential unconstrained minimization technique, sequential linear programming and dynamic programming.

8. The method of feasible direction can be grouped under the _________
a) Direct methods of approach
b) Sequential method of approach
c) Terminate method of approach
d) Laminar method of approach
Answer: a
Clarification: In non linear programming the method of feasible direction can be grouped under the direct methods of approach on general non linear inequality constrained optimization problems and two well known procedures which embody the philosophy of the method of feasible directions are Rosens gradient projection algorithum and Zountendijks procedure.

9. The first non linear programming procedure to be used in which year?
a) 1950
b) 1940
c) 1960
d) 1970
Answer: c
Clarification: This method (method of feasible direction) was probably the first non linear programming procedure to be used in structural optimization problems by schmist in 1960 and this method starting from an initial feasible point, the nearest boundary is reached and a new feasible direction is found and an appropriate step is taken along this feasible direction to get the new design point and the procedure is repeated until the optimum design point is reached.

10. One of the element considered in the economy of prestressed concrete structural system is?
a) Structural optimization
b) Beam optimization
c) Slab optimization
d) Transverse optimization
Answer: a
Clarification: Structural optimization together with the efficient management of labour, materials and the use of new construction techniques, development and use of indigenous and new materials of construction would result in considerable economy in the overall cost of prestressed concrete structural systems.

250+ TOP MCQs on Restoration of Strength of Structures and Answers

Prestressed Concrete Structures test on “Restoration of Strength of Structures”.

1. The repair and rehabilitation of damaged or spalled concrete is done by removing the ____________
a) Loose concrete
b) Collapsing
c) Breakage
d) Bonding
Answer: a
Clarification: Repair and rehabilitation of damaged or spalled concrete is done by removing the unsound or loose concrete by providing temporary supports to the girder to relieve dead load stresses and the case of pretressed concrete bridge decks, special stress check up is essential before starting the repair works.

2. In many cases of heavily loaded girders, shear distress is observed near the ____________
a) Edges
b) Supports
c) Span
d) Length
Answer: b
Clarification: In many cases of heavily loaded, girders shear distress is observed near the supports in the form of diagonal tension cracks and shear cracks may arise due to improper detailing or compaction of concrete near the support zone in such cases holes are drilled diagonally and rebars are placed and grouted to arrest the shear cracks.

3. Bridge girders located in zones of very severe exposure conditions suffer ____________
a) Spalling
b) Bleeding
c) Winding
d) Spinning
Answer: a
Clarification: Bridge girders located in zones of very severe exposure conditions are like it to suffer: Spalling extensive spalling of concrete exposing the reinforcements and in such cases the unsound or loose concrete around the girders is removed and repairing against the loss of concrete section is done by jacketing the girders using a steel form.

4. The crack propagation in the concrete girders can be arrested by using the principles of ____________
a) Pre tensioning
b) Post tensioning
c) Prestressing
d) Loading
Answer: b
Clarification: Crack propagation in the concrete girders can be arrested by using the principles of post tensioning and in this tensile cracking in the girder are arrested by including compression using tension ties forced to the sides of the girder at locations of tensile cracks.

5. In some cases of repairs of girders damaged by collision, the damage is severe what is used?
a) Trusses and bars
b) Struts and pins
c) Links and dowels
d) Lace and anchores
Answer: c
Clarification: In some cases, the damage is more severe deeper so that the high tensile wires and strands are exposed and in such cases, the damaged portion is repaired by using links ad dowels along with wire mesh tied to the reinforcements and the entire damaged part is repaired using mortar or non shrink grout.

6. The corrosion of reinforcement due to extreme exposure is common for structure located in ____________
a) Dry conditions
b) Costal zones
c) Regional zones
d) Hot condition
Answer: b
Clarification: Due to various reasons such as corrosion of reinforcements due to extreme exposure conditions, especially when un bonded tendons are used, the high tensile strands may get damaged resulting in loss of prestresss in the girder.

7. In case of damaged prestressed concrete I girders which are used for restoring strength?
a) Pretensioning
b) Post tensioning
c) Chemicals
d) Dies
Answer: b
Clarification: Post tensioning rods (one on either side of the web) in conjugation with jacking (concrete) corbels located outside the damaged areas can be used to restore the strength of the prestressed girder and to start with the calculated preload is applied and the damaged concrete is repaired.

8. In restoration of strength by adding external reinforced concrete the damages concrete is first repaired by applying ____________
a) Preload
b) Tensile load
c) Compressive load
d) Overload
Answer: a
Clarification: In this method, the damaged concrete is first repaired by applying the required preload and the concrete a corbels are constructed with the required conventional steel reinforcement and it shows adding external reinforcement concrete to restore the strength of the damaged girder.

9. In method 3 the restoration is done y addition of ____________
a) Metal sleeve jacket
b) Aluminium jacket
c) Steel jacket
d) Water proof jacket
Answer: a
Clarification: In this methods preload is applied prior to the repair of the damaged concrete and removed after the completion of repairs and a metal sleeve jacket is installed around and beyond the damaged area and the gap between the metal sleeve girders is filles with epoxy grout by pressure injection.

10. The depth of structural element is increased by adding ____________
a) Excess concrete
b) Low concrete
c) Prestressed concrete
d) Dies
Answer: a
Clarification: The depth of structural elements is increased by adding an new layer of concrete on top of an existing cross sections and bonding the old and new elements with modern epoxy resin adhesives and the total reinforcement in the cross section is increased by epoxy bonding of thin steel plates on the tension face of the beam to increase the flexural and shear strength.

To practice all areas of Prestressed Concrete Structures for tests,