Rail Structure Interaction Analysis of Steel Composite Metro Bridge

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Rail Structure Interaction Analysis of Steel Composite Metro Bridge
1Raghappa M Goykar,2Dr.P.A. Dode, 3Dr.S.A. Rasal
1Post Graduate Student, Datta Meghe College of Engineering, Navi Mumbai, Maharashtra, India
2Professor and Head, Department of Civil Engineering, Datta Meghe College of Engineering, Navi Mumbai,
Maharashtra, India
3Professor, Department of Civil Engineering, Datta Meghe College of Engineering, Navi Mumbai, Maharashtra,
India
Abstract - Continuously welded rail (CWR) with the track directly fixed on concrete deck is used for most elevated metro
bridge structures. The interaction between the CWR and elevated metro structure due to temperature variation, train
loadings like braking/traction and vertical loading takes place through directly fixed rail fasteners, which have a non-
linear force-displacement relationship. According to UIC 774-3R parameters that influence this interaction includes: Type
of superstructure, Span length, Expansion length, Bending Stiffness of the Deck and Support Stiffness. This paper presents
rail structure interaction analysis of steel composite metro bridge and case study of an under-construction metro bridge
project D.N. Nagar – Mandale, Mumbai. The total length considered for the present study is 743.43 m out of which 260.43
m is steel composite bridge portion and remaining portion are of U-Girder and PSC girder superstructure span as a
boundary condition. A three dimensional (3D) finite element analysis was carried out using the software SOFiSTiK. For
present case study results are represented in the form of axial rail stresses along the length of the bridge and checked with
UIC 774-3R permissible limits.
Key words: Rail structure interaction; Continuous welded rail; Metro bridge; UIC 774-3R
1. INTRODUCTION
A continuously welded rail (CWR) track has been extensively used many advantages. Compared with a jointed rail track,
CWR reduces the maintenance cost of the track, increase the riding quality and increases the service of track components.
The main components of CWR track bridge is elastic CWR, elastic rail fasteners which attach the rails to the concrete plinth
on the deck of the bridge, superstructure, elastic bearings which supporting the superstructure on the substructure and
substructure including foundations. Relative displacement of the rails and structure of the bridge caused by the
temperature variation, braking and vertical loading of train. Due to this track bridge interaction phenomenon results in
additional stresses to be generated in structure and therefore in rails. Mainly interaction between rails and structure take
place through the rail fasteners, which have a taking nonlinear stiffness law under consideration.
CWR directly connected to deck of the bridge by fasteners, since rails is not able to expand or contract when
temperature variation occurred in bridge. Temperature increases above the rail installation temperature causes
compressive forces in rails that would buckle the rail and temperature decrease below the rail installation temperature
causes tensile forces in the rails that would be break the rail. Also, due to rail and structure interaction phenomenon,
transverse and longitudinal shear force has been developed at bearing level that should be considered for design of
foundation and substructure. This paper focus has mainly on the rail structure interaction analysis of steel composite
bridge, for which analysis have been carried by SOFiSTiK software considering the nonlinear spring for rail and deck
connection and shear force on pier which need to be consider for substructure and foundation design.
2. LITERATURE REVIEW
The investigations on CWR forces and their influence on the design of structures have been in discussion for the last 30
years at national and international levels.
Longitudinal forces in continuously welded rails on bridge decks due to nonlinear track bridge interaction (2006)
illustrates the longitudinal stresses generated in continuously welded rails on the railway bridge. Longitudinal loads are
caused because of braking action of railway, the uniform temperature change of bridge as well as a sudden change of
ballast stiffness at a moment when train reaches the bridge. Based on study results it was found that longitudinal stresses
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 09 Issue: 11 | Nov 2022 www.irjet.net p-ISSN: 2395-0072

obtained by conventional separate treatment of loading case are higher compared to stresses calculated using proposed
correct combination of loading cases. Based on results it was concluded that in certain situations expansion devices are
not required. Maximum compressive rail stresses were considerably reduced because of proposed truly nonlinear
simulation
Longitudinal track bridge interaction for load sequence 2008) illustrates that results obtained from statical approach are
sufficiently accurate and change of coupling stiffness results in increase of largest compression force by 10% is realistic.
Author also found that multiple unloading-loading-unloading track after seasonal temperature there is increase linear
elastic part along track bridge coupling interface.
Nonlinear rail structure interaction analysis of an elevated skewed steel guideway (2011). This paper focused on
determination of rail break gap value and quantifying rail axial stresses and bearing forces and their distribution along
length of bridge. Based on result it was found that bearing transferred negligible amount of lateral forces to substructure.
Based on study it was found that 3-D modelling give broad insight into RSI forces. Author concludes broken rail gap must
be less than stipulated in design criteria.
3. OBJECTIVES OF PRESENT STUDY
The Mumbai Metro Line-2B Bridge from D.N. Nagar to Mandale has been used as a basis for this study. The configuration of
the bridge is a two-track, multi-span simply supported with steel composite girder superstructure. Adjacent spans of main
steel composite bridge are U- Girder, Pretension Prestressed Girder and Post Tensioned Prestressed Girder
superstructure. Each track structure consists essentially of two parallel rails that are directly fixed to the deck. The rails
are attached to the deck by fasteners, which are placed at fixed equal intervals along the length of the track. The reinforced
concrete (RC) substructure members are circular type piers at U girder superstructure and rectangular type piers at steel
composite and PSC superstructure are present. Foundation consists of a circular reinforced concrete group of piles. The
total length considered for the present study is 743.43 m out of which 260.43 m is steel composite bridge portion and
remaining portion are of U-Girder and PSC girder superstructure span.
The superstructure considered for the present study consists of a total 23 numbers of span with varying span length and
substructure is considered with varying height as provided in general arrangement drawing. The curvature of the bridge is
considered to measure special effect of curvature on considered steel composite bridge. The U girder and Pretensioned
girder superstructure is supported by elastomeric bearing and steel composite and post tensioned girder superstructure
supported by POT-PTFE bearing. Between two successive girder expansion gap of 50 mm is provided. There are four
number of piles of each 1m diameter and circular pier of 2m diameter is used under the standard U girder spans. And six
number of piles of each 1 m diameter and 2.2 x 2.4m rectangular pier is used under special span.
ii) To find out the additional stresses in rail and longitudinal force at bearing level.
iii) To check the additional rail stresses is under permissible limit given by UIC 774-3R.
4. BRIDGE STRUCTURE OF PRESENT STUDY
This study focuses on following objectives,
i) To carry out the RSI analysis of under construction steel composite bridge for Mumbai metro line 2B.

Figure 1: Perspective view of Bridge
5. NUMERICAL MODELING OF TRACK BRIDGE INTERACTION
To carry out numerical studies RSI of steel composite metro bridge, a numerical model has been created and the analysis
are carried out using this model. The model created for the rail structure interaction has been shown above in Fig. 1.
The numerical model is developed to simulate the rail structure interaction using the software SOFiSTiK which is based on
stiffness approach. The bridge and rails are modeled using the beam elements and the connection between the two is
modeled by nonlinear springs. The experimental data enabled to idealize the behavior by means of the adoption of a
bilinear elasto-plastic law, characterized by the maximum value of the frictional force and the value of the displacement of
yield u0. As per UIC 774 -3R,
Displacement between elastic and plastic zone
u0 = 0.5 mm
Resistances k per unit of length for one track in the
plastic zone:
- ktr = 40kN/m for unloaded track (80000 kN/m/m)
- ktr = 60kN/m for loaded track (120000 kN/m/m)
Figure 2: Force-displacement interaction law
between track and deck
Using the above force displacement diagram, connection between superstructure and rail is modelled as a spring with
bilinear elasto-plastic behaviour in transverse direction with stiffness as shown in below fig. 3 and fig. 4

Figure 3: Definition of normal force of rail spring in SOFiSTiK Figure 4: Definition of trans. force of rail spring in SOFiSTiK
The rail is connected to deck using rigid link and spring as defined above. Typical connection of the rail and U girder
superstructure are shown below in fig. 5
Figure 5: Typical connection of rail and U girder superstructure
The bearings are modelled using spring. In this study two types of bearing have been used, first type of bearing is POT
PTFE fixed and guided bearing used below steel composite and special span superstructure and second type of bearing is
elastomeric bearing which is used below standard U girder and I girder superstructure. Bearing is defined in SOFiSTiK
using work laws.
The pier cap has been modelled as beam element. The modelling has been done at the top of the pier cap and the pier
cap is connected to the pier using rigid links up to depth of pier cap. And also, superstructure connected to pier cap using
rigid links and springs to simulate the offset and elastomeric / Pot-bearings.
The piles are modelled as beam element, and fixity level is considered at 6m below pile cut off level. The piles are
connected to pier center using rigid links to simulate the rigid pile cap. 4 piles per pier have been considered for standard
spans and 6 piles have been considered for steel composite and special span in the analysis. The spacing of the piles has
been considered as 3m in transverse direction and longitudinal direction. For simplicity, the same foundation has been
considered for all piers.

6. LOADS AND ACTION
6.1 Load case 1 - Thermal effects in the combined structure and track system
a. Rail
As per UIC 774-3, in case of CWR a variation in the temperature of the track does not cause a displacement of the track.
Thus, there is no interaction effect due to the variation of the temperature in the track.
b. Superstructure
The temperature load on superstructure has been applied as per clause 1.4.2 of UIC 774-3R, which is ± 35°C.
6.2 Load case 2 - Live load effects on rails
As per clause 1.4.3 of UIC 774-3R, loads from only two tracks are to be considered for the analysis. The same clause also
specifies that braking on one track and traction on second track shall be considered.
a. Longitudinal effects
Braking and traction effects are applied along with the moving load definition in SOFiSTiK. To be on conservative side both
braking and traction are considered as 20% of the vertical axle load.
b. Vertical effects
Traffic loads cause a bending in the deck. This introduces a rotation of the end sections and displacement of upper edge of
deck. The effect of this rotation on the rails is to be evaluated. A single 6 coach train with 4 axles per coach as defined in
DBR has been considered for the analysis. The fig. 6 below shows a vertical load of a single car of metro rail. Mumbai metro
has six number of cars; each car has a length of 22.1 m and a load of 680 kN
Figure 6: Vertical load of train Figure 7: Vertical, braking and acceleration load
As per clause 1.5.2 of UIC 774-3R, for ballast less track, the additional compressive and tensile stresses in rails due to
temperature variation of the deck, barking/acceleration and deck end rotation shall be less than 92 MPa. For this check,
the results of load case 1 and 2 will be combined without any load factor.
applied in SOFiSTiK
6.3 Combination of actions and conditions to be checked
As per clause 1.5.1. of UIC 774-3R, the load factor for all loads shall be 1.
a. Check for additional stresses in rail

7. RESULTS AND DISCUSSION
In this case study the Rail Structure Interaction analysis for Steel Composite Mumbai Metro line 2B rail bridge is
performed, and results are represented for individual load. Results for effect of rail continuity on forces transferred to
substructure is also represented.
7.1 Additional stresses in rail due to temperature variation
Axial force in rail due to temperature variation are shown in below figures.
Figure 8: Axial tension force in rail due to temperature variation
Figure 9: Axial compression force in rail due to temperature variation
The maximum axial tension force in rail due to temperature = 231.1 kN
Therefore, the tensile stress in rail due to temperature = 231.1 x 1000
7670
= 30.13 MPa - Tension
The maximum axial compression force in rail due to temperature = -231.1 kN
Therefore, the compressive stress in rail due to temperature = -231.1 x 1000
7670
= -30.13 MPa - Compression

7.2 Additional stresses in rail due to live load
The critical position of live load for the governing forces in rail for steel composite span is shown below fig 10. The critical
case is when both tracks of the main line are loaded. This load takes into effect the longitudinal force due to braking /
traction and rotation of span due to vertical loads.
Figure 10: Critical live load position for steel composite span
The axial force in rail due to braking/traction and vertical live loading are shown in the below figures.
Figure 11: Axial tension force in rail due to live load
Figure 12: Axial compression force in rail due to live load

The maximum axial tension force in rail due to live load = 168.1 kN
Therefore, the tensile stress in rail due to live load = 168.1 x 1000
7670
= 21.91 MPa - Tension
The combined tensile stresses in rail due to Temperature & Live load = 30.13 + 21.91
= 52.04 MPa < 92 MPa
The maximum axial compression force in rail due to live load = - 167.8 kN
Therefore, the compressive stress in rail due to temperature = - 167.8 x 1000
7670
= - 21.87 MPa - Compression
The combined compressive stresses in rail due to Temperature & Live load = - 30.13 - 21.87
= - 52.00 MPa < 92 MPa
Table 1: Axial rail stresses for present study
Load Temperature Braking / Traction and Vertical live load Total
Tensile Stress MPa 30.13 21.91 52.04
Compressive Stress MPa - 30.13 - 21.87 - 52.00
RSI analysis for present study shows that combined axial tensile stress in the rail is 52.04 MPa and combined compressive
stress in the rail is 52.04 MPa. Which are within the permissible limit given by UIC 774-3R
7.3 LWR FORCE TRANSFERRED TO SUBSTRUCTURE
For the applied temperature loads as defined in load action point no. 6, the shear force in each pier for considered span for
RSI have been summarized below. The LWR force to be considered for analysis shall be the shear force obtained divided
by the contributary length of superstructure for that particular pier
Table 2: LWR forces transferred to substructure
Pier
No
Span Length Contributary
length
Shear
Force (kN)
Force per meter
(kN/m)
Preceding succeeding
P465 25m 25m 25m 113.4 4.54
P466 25m 25m 25m 95.3 3.81
P467 25m 25m 25m 82.4 3.30
P468 25m 25m 25m 74.5 2.98
P469 25m 25m 25m 70.4 2.82
P470 25m 25m 25m 70.7 2.83

P471 25m 25m 25m 74.7 2.99
P472 25m 25m 25m 84.5 3.38
P473 25m 25m 25m 101.2 4.05
P474 25m 43.5m 34.25m 29.4 0.86
P475 43.5m 43.43m 43.46m 12.4 0.29
P476 43.43m 43.5m 43.46m 17.1 0.39
P477 43.5m 43.5m 43.5m 12.9 0.30
P477A 43.5m 43.0m 43.25m 63.3 1.46
P478 43.0m 43.5m 43.25m 129.3 2.99
P479 43.5m 28m 35.75m 244 6.83
P480 28m 23m 25.5m 17.3 0.68
P486 23m 33m 28m 38.9 1.39
P487 33m 33m 33m 101.2 3.07
P488 33m 33m 33m 118.6 3.39
P490 33m 33m 33m 99.3 3.01
P491 33m 25m 19.33m 33.6 1.74
P492 25m 25m 25m 8.43 0.34
The maximum LWR force generated in the pier per meter running = 6.83 kN/m
The maximum force per track is = 3.41 kN/m
In the design of substructure and foundation, the LWR force considered is 4 kN/m per track
8. CONCLUSION
1. Rail Structure Interaction analysis for this case study shows that combined axial compression and tensile rail stresses
due to temperature variation and braking/traction and vertical live loads are 52.00 MPa and 52.04 MPa respectively. This
rail stresses are within the permissible limit given by UIC 774-3R. Hence no need to provide expansion devices in rail. If
stresses exceed permissible limits given by UIC 774-3R, these stresses are reduced by providing either expansion devices
or changing the other parameter like, bearing arrangement, deck expansion length.
2. Rail and structure interaction for different action of loading, transferred horizontal forces (LWR) to substructure which
is 3.41 kN/m per track. This LWR force should be considered for the design of substructure and foundation.
REFERENCES
1. RDSO Guidelines Ver 2 for carrying out Rail Structure Interaction studies on Metro Systems.
2. UIC 774-3R - Track/Bridge Interaction – Recommendations for calculations.
3. UIC 776-2R - Design requirements for rail bridges based on interaction phenomena between train, track and bridge
4. IRS CBC - Indian railway standard code of practice for plain, reinforced & prestressed concrete for general bridge
construction
5. IRS Steel Bridge code - Indian railway standard code of practice for the design of steel or wrought iron bridges carrying
rail, road or pedestrian traffic

6. P. Ruge, C. Birk (2006). Longitudinal forces in continuously welded rails on bridge decks due to nonlinear track bridge
interaction
7. D.R. Widrda, P. Ruge, C. Birk (2008). Longitudinal track bridge interaction for load sequence
8. Roman Okelo, Afisu Olabimtan (2011). Nonlinear rail structure interaction analysis of an elevated skewed steel
guideway
9. DAI Gong-lian, YAN Bin (2012). Longitudinal forces of continuously welded track on high-speed railway cable stayed
bridge considering impact of adjacent bridges
10. J. Zhang, D.J. Wu, Q. Li (2014). Loading-history based track bridge interaction analysis with experimental fastener
resistance
11. Ahammed Ali Asif, Dr. Raneesh, Sisir P. (2016). Strength problems associated with track bridge interaction in presence
of continuously welded rail
12. S. C. Yang, Senug Yup Jang (2016). Track Bridge Interaction Analysis Using Interface Elements Adaptive to various
Loading cases
13. Alfred Strauss, Saeed Karimi et al., (2017). Monitoring based nonlinear system modeling of bridge continuous
welded rail interaction
14. Wenshuo Liu, Gonglian Dai, et al,. (2017). Interaction between continuous welded rail and long span steel truss arch
bridge of high speed railway under seismic action
15. Ping Lou, Qiang Wang, FTK Au, et al,. (2019). Finite element analysis of thermal interaction of continuously welded
rails with simply supported bridge considering nonlinear stiffness
16. O. R. Ramos, F. Schanack, et al., (2019). Bridge length limits due to track structure interaction in continuous girder
prestressed concrete bridge
17. Wenshuo Lie, Hao Lai, Shiwei Rao et al., (2021). Numerical Study on Track-Bridge Interaction of Integral Railway Rigid
Frame Bridge
18. Xiangdong Yu , Nengyu Cheng , Haiquan Jing (2021). Additional Forces on Continuously Welded rail of long span high
speed railway suspension bridge under single effect and multiple effects

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