'aper / Subject Code:
59025 / Program Elective-|| Advanced Pre-stressed Concrete Structurcs
ME Gvid SemI-R-2
(3 Hours) [Total Marks: 80
N.B: (1)Question No. 1is compulsory.
(2) Attempt any three questions out of remaining five questions.
(3)Assunme suitable data wherever required and state it clearly.
(4) Ilustrate your answers with ncat component sketches wherever required.
(5) IS 1343:1980, IS 3370 and rclevant codes roquire for design are permitted.
32
1. Design apost tensioned roof girder as aclass Istructure using following data
Effective span = 40 m
Live load = 9 kN/m
Dcad load (excluding self-weight) = 2 kN/m
Load Factors (For dead load = 14, for live load 1.6)
Cube strength of concrete, fcu = 50 N/mm
Cube strength at transfer fei = 35 N/mm?
Tensile strength of concrete f = 1.7 N/mm
Modulus of elasticity of concrete Es = 34 KN/mm, Loss ratio =0.85
8 mm diameter high tensile wires having a characteristic tensile strength
fpu= 1200 N/mm are available for use.
The modulus of elasticity of high tensile wires is 200 KN/mm.
OR
for a national
Design a post-tensioned pre-stressed concrete slab bridge deck
highway crossing to suit the following data:
ultimate
Materials: M-40grade concrete, 7 mm diameter high-tensile wires with an
by
tensile strength of 1500 N/mm housed in cables with 12 wires and anchored
Freyssinst anchorage of 150 mm diameter.
Clear span = 10.2 m
Width of bearing = 400 mm
Clear width of roadway = 7.5 m
Footpath width = 1.0m on either side
Thickness of wearing coat= 80 mm
Width of kerbs = 600 mm
Assume typeof structure as class Itype
Live load I.R.C Class AA tracked vehicle
bars
For supplementary reinforcement, adopt Fe415 grade HYSD
Compressive strength at transfer fei = 35 N/mm
Loss ratio = 0.8, Permissible compressive stress at transfer and at working load
are fet =15 N/mm´,few = 12 N/mm,ft =fcw = 0
33940 Page 1 of 3
53772B9BS47340FDA877FB778778B180
Elective - I Advanced Pre-stressed Concrete Struetne
per/Subject Code: 59025 / Program
in prestressed concrete
advantages of continuous members
What are the
2. (a) structurcs?
with
concrete two-way slab, 6m x 9 m 12
Design a post-tcnsioncd pre-Stressed
imposed load of 3 KN/m Cables of four
(b) discontinuous cdges, to support an effective force of 120 KN are available
wires of 5 mm
diameter carryng an directions and check for the
cables in the two service loads.
spacing of
for usc. Design theagainst collapse and excessivedeflection at span). fek
safcty of thc slab for short span=0.089, = 0.056 for long
Assume (B.Mcocfficients N/mmand Ec =38 kN/mm
N/mm, fp =1500
=40
04
characteristics of folded plates.
Write deformation
3. (a) diameter 30 m is 12
concrete water tank of internal
cylindrical pre-stressed permissible compressive
(b) A water over a depth of 7.5m. The minimum compressive
required to store the
transfer is 13 N/mm´ and ratio is 0.75. Wires of 5
stress in concrete at loss
pressure is 1 N/mm. The N/mm are available for
stress under working of 1200
an initial stress made up of 12 wires of 8 mm
mm diameter with Freyssinet cables pre-stressing.
circumferential widening and are to be used for
vertical
Nmm concrete cube is
diameter stressed to 1200 as fixed. The strength of
assuming base
Deign the tank wall Draw sectional details.
assumed to be 40 N/mm.
case ofcomposite
section. 04
deflection in
Explain differential shrinkage and
4. (a) breadth of 100 mm 12
beam of rectangularsection has a pre
A precast pre-tensioned beam with an effective span of 5 m is
(b) mm. The the bottom kern. The
and a depth of 200 their centroids coinciding with assumed to
tendons with
stressed by
120 kN. The loss of prestress may be
initial force in the tendons
is by casting a top
beam is incorporated in a composite T-beam composite beam
be 15%.The thickness 40 mm. If the
mm and developed in
flange of breadth 400 calculate the resultant stresses
of 8 kN/m,
supports a live load following conditions:
precast and in situ cast concrete for the
the
concrete in
For the same modulus of elasticityfor
J) propped during the pre-stressed and in situ cast slab
casting ofthe slab
(i) un-propped.
04
prestressed concrete
Explain maintenance of
5. (a) bay of a biscuit 12
pre-tensioned folded plate roof for the loading to be
(b)
Design a
x 90 m. The live load on the roof may be taken
measuring 30
factory m The
available for use.
KN/m. The 8 mm diameter high tensile wires are concrete
1 1500 N/mm. M-45 grade
strength of the wires is
ultimate tensile strength of concrete
used for the casting of folded plates. The tensile
may be of 1/15
plates, 100 mm thick with a depth
is 1.6 N/mm. V-shaped folded details.
of 30 m. Draw cross-sectional
span, are proposed over a span
Page 2 of 3
33940
53772B9B547340FDA877FB778778B180
Code:59025// Program Elective -I Advanced Pre-stressed Conerete Structures
r/Subject
concrete dome of 30 mbase diamcter and a rise of 3.75 mis to 12
Areinforced tank. The shell dome to be
for a pre-stressed concrete cylindrical
6. (a)
be designed
with a pre-stresscd concrete ring beam.
Design the dome and the
provided high
for a superimposcd load of 1.5 kN/m'. The 5 mm diameter
ring beam stressed to 1000N/mm are available for pre-stressing
initially
tensile wires Theloss ratio is 0.80 and permissible compressive stress in
bcam. m,
the ring transfer is 14 N/mm Assume radius of the shell dome = 32
Concrete at
mm, semi central angle a = 28° 4',
thickness of shell =75 04
prestressed concrete
Explain variouslosses in
(b)
t***k***** ***** * **
Page 3 of3
33940
