1.
0 Introduction
1.1 General
This document presents Detailed Design of VUP (INTEGRAL TYPE) of 22.12 m Span (c/c Brg) Precast Pre
Tensioned Girder & Cast in Situ RCC Deck Slab with plank Superstructure.
The deck width comprises of two crash barriers and 13.5 m wide carriageway making a total deck
width of 14.5 m.
Apart from Dead Load of Precast Girder and Deck Slab , the superstructure is designed to cater for
Superimposed Dead Load , Live Load , Temperature Gradient Effect, Differential Shrinkage and
Differential Creep Effects.
Pretension girder is proposed as superstructure supported over end diaphragm & pier. Pile foundation
is proposed beneath the pier. This design note deals with the design of superstructure, substructure &
foundation of 22.12m c/c exp. joint integral span.
Bending moment, Shear force and torsion are calculated at critical section due to different load cases
and load combinations as per MIDAS Software.
For the design of Pretension girder, stage wise load application and stresses generated are considered.
Effect of DL, SIDL, LL,tendon primary, tendon secondary,creep primary, creep secondary, temperature
gradient are considered. The losses due to elastic shortening, shrinkage and relaxation are considered
as per IRC: 112-2020. The flexure stresses are checked under Serviceability limit state. The check for
moment of resistance and shear capacity are applied at Ultimate limit state. Appropriate load factors
for each limit state are considered while applying the effects of various loads.
For the design of Pile & Pile Cap, R=1 is adopted where as for Pier R=3 is adopted. Bending moment,
Shear force and torsion are calculated at critical section due to different load cases and load
combinations as per MIDAS Software. Structural design of the above components is carried out in
ADSEC software.
1.2 Construction Methodology
The Structure shall be constructed in the following sequence:
1 The foundation and substructure shall be cast-in-situ upto top of abutment shaft.
2 Precast Girder shall be cast in casting yard. Dowel bars for end diaphragm shall be left out.
Precast Girder shall be launched after 28 days of casting or attains 45 Mpa whichever is less & kept at
3
temperory support over cribs.
4 Concrete for end diaphragm shall be poured (in single pouring) after binding the steel.
5 Place precast deck panels over the girder after 28 days of casting or attains 40 Mpa whichever is less.
Ensure that end diaphragm attains 35 Mpa before placing pre cast deck slab panels.
6 Concrete for cast-in-situ deck slab shall be poured (in single pouring) after binding the steel.
5 SIDL shall be placed on deck after 28 days of casting of deck slab.
6 Structure shall be opened for live load after 21 days of placing of SIDL.
Construction Stages in MIDAS
a) Girder Only
b) Diaphragm weight
c) Diaphragm active
d) Wet concrete
e) Deck active
f) SIDL active
g) LL active
1.3 Structure Idealisation
The Pretension girder is being idealized in MIDAS Civil software, as a grillage model, for longitudinal
analysis and stress check . ULS & crack width check are performed in Adsec.
1.4 Codes
The design is based upon the provisions from following codes:
a) IRC: 6-2017 Standard Specifications and Code of Practice
for Road Bridges Section : II Loads and
b) IRC: 112-2020
Code of Practice for Concrete Road Bridges
c) IRC:SP :71-2018 Design & construction of precast pretension
girder
SALIENT FEATURES OF THE BRIDGE DECK:
Skew angle = 0.00 degree
Span c/c of Exp. J. = 22.120 m skew
Exp. Gap = 20 mm sq
c/L of pier. c/L of exp. J = 0.510 m skew
Span c/c of pier. = 21.000 m
Overall span = 22.100 m
Overhang beyond c/L brg. = 0.550 m
Thickness of End Cross-Girder = 1.200 m
Thickness of Intermidate Cross-Girder = 0.000 m
Clear gap b/w end cross girder & Long. Girder = 0.000 m
Girder overhang beyond c/l brg. = 0.000 m
Overall Length of Girder = 20.000 m
c/L of temporary brg. from face of X girder = 0.300 m
Overall carriageway width = 14.500 m
Wearing Coat Thickness = 50 mm
Depth of Precast Beam = 1.000 m
Thickness of Cast-in-situ deck = 0.220 m
Overall depth Beam +slab = 1.220 m
c/c of girder (transvers direction) = 3 m
Nos. of Girder = 5 Nos.
Deck cantilever in transverse direction = 1.250 m
Cover
Precast Plank 40 mm
Deck slab 40 mm
3
Density of Concrete = 2.500 t/m
PROPORTINING OF PRECAST BEAM
1.000 1.000
0.100 0.100
ht1 0.100 0.065
0.160 1.000 0.450 1.000
0.150 0.076
0.200 0.200
bw2 = 0.750 0.750
Section at Mid Span Section at Support
Web Thickening
1.2 0.000
-0.05 0.3 c/L
0.45 0.160
0.000
0.55 2.000 1.500 7.00
10.500
web thickness variation along span
c/L Temp. brg.
c/L Pier
Web Thickening
Section At c/L brg. Temp. brg Tap. S L/16 deff Tap End 2L/16 3L/16 4L/16 5L/16 6L/16 7L/16 8L/16
Dist. From c/L 0.00 0.90 2.00 1.31 1.64 3.50 2.63 3.94 5.25 6.56 7.88 9.19 10.50
Permanent brg. (m)
Dist. From face of -0.50 0.40 1.50 0.81 1.14 3.00 2.13 3.44 4.75 6.06 7.38 8.69 10.00
girder (m)
Dist. From c/L -0.90 0.00 1.10 0.41 0.74 2.60 1.73 3.04 4.35 5.66 6.98 8.29 9.60
temp. brg. (m)
bw 0.45 0.45 0.45 0.450 0.450 0.16 0.32917 0.16 0.16 0.16 0.16 0.16 0.16
Overall depth of composite girder 1.22 m
deff = 1.04 */Assumed 0.85 times of overall depth
MATERIAL USED :
Grade of Reinforcement = Fe 550
fyk = 550 Mpa
Modulus of Elasticity Es = 200000 Mpa
Cast insitu deck = M 40
fck = 40 Mpa
fcm = 50 MPa
Ecm = 33000 MPa
Precast Beam = M 55
fck = 55 Mpa
fcm = 65 MPa
Ecm = 36076 MPa
fctk,0.05 = Characteristic axial tensile strength of concrete
= 2.6 MPa
ANALYSES ASSUMPTION
Enviromental parameters
Relative humidity = 64.5 %
Exposure condition = SEVERE
TEMPERATURE
o
Coefficent of thermal expansion = 0.000012 / C
FOR PRECAST BEAM
Modulus of Elasticity
For short Term loading Ecm = 36076.44 Mpa
For long Term loading Ecm' = Ecm/ (1+f)
f = Creep coefficent
SERVICEABILITY LIMIT STATE :
Rare Combination
Max permissible Stress in Concrete = 0.48*fck = 26.4 Mpa
Permissible stress in Concrete = 0.48*fck = 20.67 Mpa (At 7 days)
Max permissible tensile Stress in Concrete
fctm = -3.746 Mpa =fctm ( mean tensile strength)
fctd = -3.18 Mpa =fctm ( design tensile strength)
Quasi permanent Combination
Max permissible Stress in Concrete = 0.36*fck = 20 Mpa
Max permissible Stress in Steel = 0.8*fyk = 400 Mpa
Permissible crack width wk,max = 0.2 mm
c/L Brg.
CRASH BARRIER 0.500
14.500
13.500
CRASH BARRIER 0.500
21
22.1
PLAN
14.5
0.22
c/L Jack Nos of Girder = 5 1.00 1.22
0
1.250 3
Super-structure Cross-section
