Comparitive analysis of box girder birdge

International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 3, May - June (2013), © IAEME
111
COMPARITIVE ANALYSIS OF BOX GIRDER BIRDGE WITH TWO
DIFFERENT CODES
Patil Yashavant S.1
, Prof. Shinde Sangita B.2
1
P.G. Student, Dept. of Structural Engineering,
Jawaharlal Nehru Engineering College, Aurangabad-431003, Maharashtra. India.
2
Asst. Professor, Dept. of Structural Engineering,
Jawaharlal Nehru Engineering College, Aurangabad-431003. Maharashtra, India.
ABSTRACT
The design of a highway bridge is critically dependent on standards and criteria.
Naturally, the importance of highway bridges in a modern transportation system would imply
a set of rigorous design specifications to ensure the safety, quality and overall cost of the
project. This paper discusses the comparative analysis of two standards namely AASHTO and
IRC followed in construction of bridge superstructures subjected to load of heavy vehicles.
To find out optimized cross section, variety of checks and exercise are performed that are
presented in this paper. As a result of this exercise it is clear that results of bending moment
and stress for self-weight and superimposed weight are same, but those are different for the
moving load consideration, this is due to the fact that IRC codes gives design for the heavy
loading compared to the AASHTO codes. In load combination, AASHTO codes have taken
more factor of safety than IRC. Area of prestressing steel required for AASHTO is less
compared to IRC. The results also showed the IRC codes are costly because for same
dimension the numbers of Strand in the Web are more than those with AASHTO code.
Analysis is carried out using the MIDAS CIVIL of finite elements base modeling.
Keywords- Concrete Box Girder Bridge, impact factor, Prestress Force, shear strength,
MIDAS CIVIL Model
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING AND
TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 4, Issue 3, May - June (2013), pp. 111-120
© IAEME: www.iaeme.com/ijciet.asp
Journal Impact Factor (2013): 5.3277 (Calculated by GISI)
www.jifactor.com
IJCIET
© IAEME

112
I. INTRODUCTION
For design of Mega Bridge superstructures there are many codes used around the
world and most of countries have their own code depending on the natural conditions and the
surrounding environmental factors, such as the effect of earthquakes and heavy snowfall, etc.
In the United States, Bridge Engineers use the code of AASHTO “American Association of
State Highway and Transportation Officials”; this code can be adopted for design of the
highway bridges with special requirements. Similarly, Indian bridge engineers refer to the
IRC (Indian Road Congress) standard to do the design. However The AASHTO Standard
Specification is adopted by many countries as the general code for bridge designs.
While designing project two different codes might result in different design. Therefore to
choose the most appropriate one, it’s important to do comparative analysis of codes and their
resulting design. To prove this hypothesis in this study following two codes are adopted
1) AASHTO-LRFD Bridge Design Specifications
2) IRC and IS codes Design Specification
The Two codes will be used to do the analysis of Box Girder. The similarities and differences,
advantages and disadvantages of each code will be investigated.
II. MATERIAL PROPERTIES AND ALLOWABLE STRESS
Concrete properties: Grade: M45
Tendon Properties:
P .C Strand: Φ15.2 mm (0.6˝strand)
Yield Strength: fpy = 1600 N/mm2
Ultimate Strength: fpu = 1900 N/mm2
Cross Sectional area of each tendon = 140 mm2
Modulus of Elasticity: Eps = 2.0 X 105
N/mm2
Jacking Stress: fpj = 0.7fpu = 1330 N/mm2
Curvature friction factor: µ = 0.3 /rad
Wobble friction factor: k = 0.0066 /m
Anchorage Slip: ∆s = 6 mm (At the Beginning and at the End)
III. CROSS SECTION SPECIFICATION
Span = 50m
Total width = 9.850m
Road width = 8.750m
Wearing coat = 100mm
Area : 4.95 m²
Ixx : 5.73 m4
Iyy : 2.47 m4
Izz : 2.80 m4
Center: y : 1.05 m
Center: z : 4.93 m

113
Checks for optimization of cross section dimensions :-( AASHTO-LRFD 5.14.2.3.10)
1. Check the thickness of flanges
- Top flanges:
Clear span between webs, lw = 4500 mm
Minimum thickness = 4.5/30 =150 mm
Top flange thickness = 300 mm. OK.
- Bottom flanges:
Clear span between webs, lw = 3800 mm
Minimum thickness = 3800/30 =126.6 mm
Bottom flange thickness = 200 mm. OK.
2. Check whether transverse prestressing is required or not
lw = 4.500 m < 4.57 m( = 15 feet) Transverse prestressing not required.
3. Check web thickness
Total depth = 2000 mm
Minimum thickness, tmin = 2000/15=133mm (= 12 inches)
Web thickness, tw = 300 mm. OK.
4. Check the length of top flange cantilever
The distance between centerline of the webs: ln = 4925 mm
ln X 0.45 = 2216 mm > 1500 mm. OK.
5. Check overall cross-section dimensions
Maximum live load plus impact deflection: 6.433 mm
Deflection limit, L/1000 = 30000/1000 = 30 mm. OK.
Figure 1. Cross section of Box girder
IV. LOADING ON BOX GIRDER BRIDGE
The various type of loads, forces and stresses to be considered in the analysis and
design of the various components of the bridge are given in the IRC 6:2000(Section II) and
AASHTO-LRFD (Section 3) But the common forces are considered to design the model are
as follows:

114
Dead Load (DL)
The dead load carried by the girder or the member consists of its own weight and the
portions of the weight of the superstructure and any fixed loads supported by the member.
The dead load can be estimated fairly accurately during design and can be controlled during
construction and service.
Superimposed Dead Load (SIDL)
The weight of superimposed dead load includes footpaths, earth-fills, wearing course,
stay-in-place forms, ballast, water-proofing, signs, architectural ornamentation, pipes,
conduits, cables and any other immovable appurtenances installed on the structure.
Wearing coat = 0.1x8.750x18 = 15.75kN/m
Footway Load: (As per the IRC 6 -2000 clause 209)
P = ࢖′
െ ቀ
૝૙ࡸି૜૙૙
ૢ
ቁ
Where,
P = Live Load in KN/m2
P’ = As per the case 40KN/m2
or 50 KN/m2
L= The effective span of girder
P = ࢖′
െ ቀ
૝૙ࢄ૜૙ି૜૙૙
ૢ
ቁ
P=300kg/m2
P=3KN/m2
Total superimposed load = 15.75+ (3x1) = 18.75kN/m
Live Load (LL)
Live loads are those caused by vehicles which pass over the bridge and are transient
in nature. These loads cannot be estimated precisely, and the designer has very little control
over them once the bridge is opened to traffic. In this case Following types of loadings are
adopted for the analysis of two lane box girder,
As per IRC
Vehicle Load: - Class AA and Class A
Dynamic Allowance: - 33%
As per AASTHO
Vehicle Load: - HL-93TDM, HL-93TRK
Dynamic Allowance: - 33%
Wind Loads
Wind Load: 3 kN/m
Total Height = Section Depth + Barrier = 2+1.55 = 3.55 m
Wind Pressure = 3 kN/m2
Wind Load = 3.55 m X 3 KN/m2
= 10.65 kN/m (Horizontal Load)
= 10.65 kN/m X -1.33m = -28.47 kN.m/m (Moment)

115
Figure 2. Wind load distribution
Losses in Prestress
While assessing the stresses in concrete and steel during tensioning operations and
later in service, due regard shall be paid to all losses and variations in stress resulting from
creep of concrete, shrinkage of concrete, relaxation of steel, the shortening (elastic
deformation ) of concrete at transfer, and friction and slip of anchorage.
In computing the losses in prestress when untensioned reinforcement is present, the effect of
the tensile stresses developed by the untensioned reinforcement due to shrinkage and creep
shall be considered.
V. MIDAS CIVIL MODELING
Figure 3: Midas Civil Model
VI. RESULTS AND DISCUSSION
The analysis of Box girder is done with the help of MIDAS civil Modelling,The Bending
moment and shear force result for the self weight of Box girder is shown below,which are
to be same for both the cases.

International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 3, May
Figure 4 :
Figure 5:
Impact factor: As per the IRC 6
Impact factor for Class A loading =
As Per the AASHTO =
Load combination :
The load combination for both code are different,which are tabulated as below,
Code Self weight
IRC 1
AASHTO 1.25
Reactions for moving load are different, because weight of vehicle are different changes as
we change the code, In IRC 6-2000 class
two track each of weight 350kN
trailer transmits loads from 8 axles varying from a minimum of 27kN to a maximum of
114kN. It’s a 554kN train of wheeled vehicles on eight axles.
For the AASHTO code, the
with the uniformly distributed load intensity of 9.34 kN/m ,
Effect of moving load on Girder as mention in table 2
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976
6316(Online) Volume 4, Issue 3, May - June (2013), © IAEME
116
Figure 4 : Bending moment due to self weight
5: Beam Stress Diagram for Self weight
As per the IRC 6-2000 (clause 211.2)
factor for Class A loading = = 0.125
As Per the AASHTO = = 0.405
The load combination for both code are different,which are tabulated as below,
Self weight Superimposed load Moving Load
1 1
1.25 1.75
Table 1 :Load Combination
2000 class AA types vehicle having a weight of 700kN with
ach of weight 350kN and class A types vehicle i.e., heavy duty truck with two
114kN. It’s a 554kN train of wheeled vehicles on eight axles.
For the AASHTO code, the HL-93TDM andHL-93TRK types loading are consider
with the uniformly distributed load intensity of 9.34 kN/m , Shear-z ,torsion, moment
on Girder as mention in table 2,
June (2013), © IAEME
Load
weight of 700kN with
and class A types vehicle i.e., heavy duty truck with two
93TRK types loading are considered,
z ,torsion, moment-y

117
Element
IRC AASHTO
Shear-z (kN)
Torsion
(kN*m)
Moment-y
(kN*m)
Shear-z
(kN)
Torsion
(kN*m)
Moment-y
(kN*m)
1 -1591.2 4355.62 0 -489.25 1548.01 0
2 -1425.21 3892.26 4311.36 -410.24 1336.88 1274.8
3 -1037.45 -3349.94 7141.65 -336.6 1135.84 2170.74
4 -875.88 -2965.53 9632.31 -268.86 944.89 2708.51
5 -689.22 2502.17 9902.91 -207.49 764.03 2949.62
6 862.05 1959.85 9997.5 257.77 593.25 2902.3
7 1014.94 2409.49 9355.6 321.51 764.03 2595.93
8 1357.64 2965.53 7435.09 385.52 944.89 2014.99
9 1537.66 3197.21 4586.12 448.84 1135.84 1204.59
10 1699.92 3799.59 -6069.54 510.48 -1336.9 -1445.61
11 -1851.85 4355.62 -9216.07 -554.15 1548.01 -2292.14
12 -1691.95 3813.31 -6413.02 -486.8 1336.88 -1673.55
13 -1364.27 3428.89 -4701.88 -417.84 1135.84 -1328.46
14 -1195.85 -2965.53 6536.63 -349.26 944.89 1857.06
15 -1031.58 2423.22 7845.99 -282.91 764.03 2274.41
16 -725.24 2038.8 8316.06 -220.51 593.25 2402.2
17 961.68 2502.17 8078.13 276.66 764.03 2292.49
18 1170.49 2733.85 6928.24 343.16 944.89 1894.03
19 1325.59 3289.89 4905.49 411.48 1135.84 1230.94
20 1616.04 3892.26 -5423.25 479.74 1336.88 -1413.01
21 -1815.89 4268.09 -8001.56 -545.92 1548.01 -1986.13
22 -1616.04 3892.26 -5423.25 -479.74 1336.88 -1413.01
23 -1333.27 3428.89 4905.49 -411.48 1135.84 1230.94
24 -1170.49 2886.58 6928.24 -343.16 944.89 1894.03
25 -961.68 2502.17 8078.13 -276.66 764.03 2292.49
26 710.84 2038.8 8316.06 220.51 593.25 2402.2
27 1031.58 2270.48 7845.99 282.91 764.03 2274.41
28 1150.73 2826.52 6536.63 349.26 944.89 1857.06
29 1356.32 3428.89 -4701.88 417.84 1135.84 -1328.46
30 1691.95 3660.57 -6413.02 486.8 -1336.9 -1673.55
31 -1907.47 4355.62 -9216.07 -569.39 1548.01 -2292.14
32 -1706.56 -3892.26 -6069.54 -510.48 1336.88 -1445.61
33 -1537.66 -3349.95 4586.12 -448.84 1135.84 1204.59
34 -1357.64 -2965.53 7435.09 -385.52 944.89 2014.99
35 -1102.45 2502.17 9355.6 -321.51 764.03 2595.93
36 -862.05 1959.86 9997.5 -257.77 593.25 2902.3
37 -659.09 2363.16 9902.91 207.49 764.03 2949.62
38 845.47 2919.19 9632.31 268.86 944.89 2708.51
39 1013.62 3197.21 7141.65 336.6 1135.84 2170.74
40 1425.21 3753.25 4311.36 410.24 -1336.9 1274.8
41 1591.2 4355.62 0 489.25 1548.01 0
Table 2: Shear-z, torsion, moment-z due to moving load comparison

118
As we observer the table values, Shear-z, torsion, moment-y effect on girder due to IRC loading is
more as compared to AASHTO loading, i.e., because of heavy vehicle load consideration in IRC as
compared to AASHTO, but as per as impact factors concern, for AASHTO impact factor is 0.405 and
for the IRC impact factor is 0.125, which are mention in above calculations. It means consideration of
impact factor in AASHTO is more compared to IRC.
Considering load combination of self-weight, superimposed dead load, moving load i.e., live load for
the finding ultimate moments and stress as per the codes, which are tabulated in table 3,
Element
IRC AASHTO
Shear-z (kN)
Torsion
(kN*m)
Moment-y
(kN*m)
Shear-z
(kN)
Torsion
(kN*m)
Moment-y
(kN*m)
1 -3196.01 4355.62 0 -2859.5 2709.02 0
2 -2623.38 3892.26 8515.85 -2213.62 2339.55 7479.45
3 -1829 -3349.94 14330.73 -1577.15 1987.73 12773.03
4 -1260.79 -2965.53 18586.06 -950.99 1653.56 15917.01
5 680.82 2502.17 19401.42 368.66 1337.05 17018.98
6 1290.42 1959.85 18820.87 985.83 1038.18 16093.38
7 1849.95 2409.49 16283.92 1605 1337.05 13191.62
8 2599.28 2965.53 11248.44 2224.61 1653.56 8286.51
9 3185.94 3197.21 -4612.2 2843.03 1987.73 -2600.79
10 3754.83 3799.59 -12145.8 3458.51 -2339.55 -10115
11 -4016.59 4355.62 -22067.1 -3672.05 2709.02 -20053.3
12 -3450.06 3813.31 -13379.7 -3046.58 2339.55 -11625.4
13 -2715.74 3428.89 -7004.22 -2418.29 1987.73 -5198.86
14 -2140.69 -2965.53 7678.75 -1790.66 1653.56 4675.57
15 -1569.78 2423.22 11212.65 -1166.94 1337.05 8182.88
16 -856.8 2038.8 12687.36 -550.13 1038.19 9660.62
17 1236.75 2502.17 12234.17 827.53 1337.05 9199.91
18 1852.2 2733.85 9649.1 1451.52 1653.56 6711.05
19 2413.94 3289.89 4971.27 2078.7 1987.73 2236.26
20 3111.02 3892.26 -9232.47 2705.76 2339.55 -7227.88
21 -3717.5 4268.09 -16905.7 -3329.18 2709.02 -14590.9
22 -3111.02 3892.26 -9232.47 -2705.76 2339.55 -7227.88
23 -2421.62 3428.89 4971.27 -2078.7 1987.73 2236.26
24 -1852.2 2886.58 9649.1 -1451.52 1653.56 6711.05
25 -1236.75 2502.17 12234.17 -827.53 1337.05 9199.91
26 842.4 2038.8 12687.36 550.13 1038.19 9660.62
27 1569.78 2270.48 11212.65 1166.94 1337.05 8182.88
28 2095.56 2826.52 7678.75 1790.66 1653.56 4675.57
29 2707.79 3428.89 -7004.22 2418.29 1987.73 -5198.86
30 3450.06 3660.57 -13379.7 3046.58 -2339.55 -11625.4
31 -4369.02 4355.62 -22067.1 -4069.22 2709.02 -20053.3
32 -3761.47 -3892.26 -12145.8 -3458.51 2339.55 -10115
33 -3185.94 -3349.95 -4612.2 -2843.03 1987.73 -2600.79
34 -2599.28 -2965.53 11248.44 -2224.61 1653.56 8286.51
35 -1937.45 2502.17 16283.92 -1605 1337.05 13191.62
36 -1290.42 1959.86 18820.87 -985.83 1038.19 16093.38
37 -680.82 2363.16 19401.42 -368.66 1337.05 17018.98
38 1230.37 2919.19 18586.06 950.99 1653.56 15917.01
39 1805.17 3197.21 14330.73 1577.15 1987.73 12773.03
40 2623.38 3753.25 8515.85 2213.62 -2339.55 7479.45
41 3196.01 4355.62 0 2859.5 2709.02 0
Table 3: Shear-z, torsion, moment-z due to load combination comparison

119
From the above table, bending moment at end support are zero, due to simply support
condition, but in the intermediate support it shows the negative bending moment which is to
be less compare to positive bending moment.
Comparing both the results, IRC combination show more moment compared to the
AASHTO combination, i.e., because of heavy moving load consideration, while observing
load combination multiplying factor for self-weight, 2nd
dead load, moving load are one for
IRC, but in AASHTO 1.25,1.25,1.75 respectively. It shows that consideration of factor of
safety is more in AASHTO.
Calculation of Prestressing force
IRC AASHTO
fbr 0.8x 0.45x 45 = 16 N/mm2
0.8x 0.45x 45 = 16 N/mm2
finf
ଶ.ଶ଴଺଻୶୉ଵ଴
଴.଼ଵ୶ଵ.଼ହ୶୉ଽ
=14.91 N/mm2 ଶ୶୉ଵ଴
଴.଼ଵ୶ଵ.଼ହ୶୉ଽ
= 13 N/mm2
Prestressing
force
ସ.ଽସ଼ଽ୶୉଺ ୶ ଵସ.ଵଵ ୶ ଵ.଼ହ ୶୉ଽ
ଵ.଼ହ୶୉ଽାସ.ଽସ଼ଽ ଡ଼ ୉଺ ଡ଼ ଻଴଴
=
24308.998 kN
ସ.ଽସ଼ଽ୶୉଺ ୶ ଵଷ ୶ ଵ.଼ହ ୶୉ଽ
ଵ.଼ହ୶୉ଽାସ.ଽସ଼ଽ ଡ଼ ୉଺ ଡ଼ ଻଴଴
=
22396.667 kN
Anchorage
type
19K -15 (15.2mmϕ,19 strands)
Duct Dia=95mm
27K -15 (15.2mmϕ,19 strands)
Duct Dia =110mm
No. of
cables
8 4
Area 21280 mm2
15120 mm2
Table 4: Prestress calculation
VII. CONCLUSION
This paper presents comparative analysis of concrete box girder that would help
designer while considering different factors based on code at the beginning of the project. We
also showed how to use MIDAS civil use for the analysis of box girder. It gives result based
on finite element modeling, node by node result are specified in above tables, Box girder
shows better resistance to the torsion of superstructure.
For the optimization of section, different types of check need to be performed; those
are carried out in this paper. Results of bending moment and stress for self-weight and
superimposed weight are same, but those are different for the moving load consideration,
because IRC codes gives design for the heavy loading compared to the AASHTO codes. In
load combination, AASHTO codes have taken more factor of safety than IRC. Area of
prestressing steel required for AASHTO is less compared to IRC. Finally based on this
comparative study it’s clear that AASHTO code is more economical than IRC.

120
REFERENCES
1. IRC: 6- 2000 “Standard specifications and code of practice for road bridges” Indian
road congress.
2. IRC: 18 – 2000 “Design criteria for prestressed concrete road bridges (post –
tensioned concrete)” Indian roads congress.
3. IS: 1343 – 1980 “Code of practice for prestressed concrete” Indian standard.
4. IRC: 21 –2000 “Standard specification and code of practice for road bridges (Plain
and Reinforced)” Indian road congress.
5. AASHTO (2007). “AASHTO-LRFD Bridge Design Specifications”
6. Hussein Yousif Aziz and Jianlin Ma, “Design and analysis of bridge foundation with
different codes”, Journal of Civil Engineering and Construction Technology Vol.
2(5), pp. 101-118, May 2011.
7. Priyanka Bhivgade, “Analysis and design of prestressed concrete box Girder Bridge”
Civil engineering portal.
8. Young-Ha Park and Chan-Min Park, “Development of Long Span Prestressed
Concrete I Girder Bridge by Optimal Design” expressway transportation research
institute 08-06.
9. V.N. H EGGADE, R.K. MEHTA & R. P RAKASH,” Design and Construction of
Pre-Tensioned Sutlej Bridge in Punjab” 143-158.
10. Hussein Yousif Aziz and Jianlin Ma,“Experimental and Theoretical Static Analysis of
High-Speed Railway” The Open Construction and Building Technology Journal,2012,
6, 17-31
11. RICHARD A. MILLER “AASHTO LRFD Bridge Design Specifications of
Prestressed Concrete” AASHTO-LRFD Specification, 4th Edition
12. S. Rana & R.Ahsan, “Design of prestressed concrete I-girder bridge superstructure
using optimization algorithm”, IABSE-JSCE Joint Conference on Advances in Bridge
Engineering-II, August 8-10, 2010.
13. Text Book of “Design of Bridges”, By N. Krishna Raju, Fourth Edition OXFORD &
IBH PUBLISHING CO. PVT. LTD.
14. Text Book of “Prestressed Concrete a fundamental Approach”, By Edward G. Nawy,
Fifth Edition.
15. Prof. P.T. Nimbalkar and Mr.Vipin Chandra, “Estimation Of Bridge Pier Scour For
Clear Water & Live Bed Scour Condition” International Journal of Civil Engineering
& Technology (IJCIET),Volume 4,Issue 3, 2013, pp. 92 - 97, ISSN Print: 0976 –
6308, ISSN Online: 0976 – 6316
16. Vinod P, Lalumangal And Jeenu G, “Durability Studies On High Strength High
Performance Concrete” International Journal of Civil Engineering & Technology
(IJCIET), Volume 4,Issue 1, 2013, pp.16 - 25, ISSN Print: 0976 – 6308, ISSN Online:
0976 – 6316

Comparitive analysis of box girder birdge

Recommended

Recommended

More Related Content

What's hot

What's hot (17)

Similar to Comparitive analysis of box girder birdge

Similar to Comparitive analysis of box girder birdge (20)

More from IAEME Publication

More from IAEME Publication (20)

Recently uploaded

Recently uploaded (20)

Comparitive analysis of box girder birdge