Posibilities and advances of the ERS system for bridge restoration

Posibilities and advances of the ERS system for bridge restoration

Pavel Ryjáček

CTU IN PRAGUE, FACULTY OF CIVIL ENGINEERING DEPARTMENT OF STEEL AND TIMBER STRUCTURES

Introduction

• Description of the ERS system • Results from the tests, performed recently at the

CTU • Application of the results on the Starý Most,

Bratislava • Bridge project description • ERS application • Numerical analysis and verification • Construction of the bridge

• Conclusions

ERS – Embedded rail system

• Perspective rail fastening system • Suitable for renovation of bridges, excellent noise absorption • Low buckling risk, low structural depth • Insufficient information for the structural analysis of bridges • Lack of longitudinal resistance parameters (very limited knowledge

in UIC 774-3) • The rail is embedded by PUR elastic material, filled with cork

aggregate

Bridge – rail interaction

Motivation - actual problems: • Continuous welded rail on the bridge – results in the combined

response and coupling between the bridge and the rail • Parameters affecting B/R interaction:

• Structural and geometrical properties of both the bridge and the rail • Bridge span arrangement • Bridge deck type (type of fastening) • Vertical and horizontal loads – traffic, temperature change

Bridge – rail interaction

Motivation - actual problems: • Leads to the horizontal reactions and additional stresses in the rail • Risk – rail brake – rail buckling • Insufficient interaction data for the numerical models, especially for

ERS

ERS – laboratory test

Objectives: • Simulate the behaviour of the CWR, loaded by various vertical rail

wheel load (0, 40, 80, 125 kN) and longitudinal displacement from temperature change

• Simulation based on the typical bridge stringer, L=2500 mm, loaded as a simply supported beam

• Simulate on the numerical model and perform: • Longitudinal resistance parameters under different load • Establish the load pattern for the design of the supporting

substructure

ERS – laboratory test

• The rail is embedded by PUR elastic material, filled with cork aggregate

• Embedded in the steel channel, representing the steel bridge • Loaded vertically, horizontally, measures stresses, displacement

Support

Horizontal

force

Vertical force

ERS – 3D FEM simulation

• 3D FEM model created, verified and validated • Based on the model, the load distribution principle was analysed

and design criteria established

ERS – 3D FEM simulation

• 3D FEM model created, verified and validated • Comparison of the model and reality in the end part

ERS rail – main results

• Surprisingly, opposite to the standard UIC 774-3, the longitudinal resistance is not affected by the vertical force, and it is slightly lower under the load!


• Important factor is the speed of the load – high speed (braking, acceleration) = higher longitudinal resistance, low speed (temperature change) – smaller longitudinal resistance


• Longitudinal resistance k significantly (app. 2x) higher, than values in the UIC 774-3 code

• Even for the longitudinal displacement of 19 mm no failure of the adhesive layer observed, limited problems only at the end of the resilient pad and the rail bottom part.

Unloaded track (kN/mm) Loaded track(kN/mm)

UIC 774-3 13 19

Test results 33.01 30.66


• Based on the numerical model, the vertical pressure of the rail on the main bridge structure analysed

• The corresponding effective width and length establishes, as a guide for the analysis


• The important is the impact of the ERS on the steel structure stresses

• There is the „reinforcing“ effect – the reduction of the stresses in the upper flange

• Useful for the application on the old bridges

Laboratory work conclusion • Many important information and knowledge obtained from the

work and tests • Next work will be focused on the speed and temperature

impact on the longitudinal resistance • Results recently (2015) directly applied on the widest

application of the ERS in middle Europe – „Starý most“ – 464 m long, Bratislava, Slovakia

Starý most project description

• The bridge was demolished during WWII by retreating german army

• After the war, the temporary steel bridge was built by german captured soldiers by Red army

• It has served till 1972 as a only bridge in Bratislava, with the tram and 2 lanes road


• Project owner: City of Bratislava • Contractor: Eurovia SK, Eurovia CZ • Designer: ALFA 04, Reming Consult • 2 tram train tracks, 2 pedestrian walkways


• Total legth 465,4 m, span 32+107+137+75+75+32 m

Starý most - ERS application

• Specific rail requirements: • Conventional tram in Bratislava, with gauge 1000 mm • Proposed new Tram-Train vehicle, with gauge 1435 mm • This resulted in multiple rail solution, in the urban area • The ERS system was proposed to be applied here

Starý most - numerical analysis

• Analysis of the ERS behaviour with interaction with the bridge • Fulfilment of the EN 1991-2 requirements for the stress and

displacement limits was verified on the 2D nonlinear model, the coupling interface was modelled by the nonlinear hinges


• The temperature difference between the rail and bridge results in the axial force in the rail:

• Impact of the vertical load on the axial force in the rail:

Breathing end Breathing end


• Detail analysis of the transition zone by expansion joint • 3D solid model, loaded by longitudinal displacement (from

temperature variation) and wheel load

• Impact of the vertical load on the axial force in the rail:


• Resulting stresses showed very good behaviour of the ERS • Allowable stesses were only exceeded in the small regions in PUR

blocks • Reccomended to use full resin VA-60 in the breathing end zone, in

between the PUR foam blocks can be used.

Starý most – construction process

• Steel structure erection by use of longitudinal launching







Conclusion

• ERS – perspective rail fastening system • The design knowledge developed and tested in

the laboratory • The results free to the public • The ERS solution in the fast development –

recently many important applications worldwide

Thank you for your attention

Research reported in this paper was supported by Competence Centres program of Technology Agency of the

Czech Republic (TA CR), project Centre for Effective and Sustainable Transport Infrastructure (no. TE01020168).

The authors greatly acknowledge the support and help from Edilon Sedra Inc. and SDS EXMOST spol. s.r.o..

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Posibilities and advances of the ERS system for bridge restoration