Seismic Control of a Concrete Bridge with Hybrid Passive Control Devices

Abstract

This study focuses on the seismic response of a three-span deck slab RCC T-Girder bridge with and without LRB (Lead Rubber Bearing) and in combination with LRB and FVD (Fluid Viscous Damper). The bridge is subjected to AASHTO, IRC design standards, and IRC Class A vehicle load. Linear time history analysis using CsiBridge and SAPfire is conducted to assess the bridge\'s seismic behavior. Excessive deck displacement, which can lead to deck failure and bridge closure, is a key concern. The study utilizes finite element analysis with Csibridge and incorporates viscous dampers throughout the bridge. The findings show that the presence of supplemental dampers significantly reduces pier top displacements. Base shear, deck displacement, pier response, and structural time period are the primary response parameters examined. The effectiveness of different isolation system configurations is compared to the non-isolated bridge in terms of these response characteristics. The study offers suggestions for design improvements to enhance the structure\'s performance.

Introduction

I. INTRODUCTION

This paper explores the use of hybrid passive devices, including elastomeric bearings and viscous dampers, in RC bridges to enhance seismic behavior. Upgrading bridges is vital to mitigate collapse and lengthy closures due to excessive deck displacement. Base isolation and dampers effectively improve seismic performance, allowing non-structural components to withstand earthquake forces. While elastomeric bearings can resist minor vibrations, dampers optimize structural performance during strong seismic events. Energy dissipation devices like laminated rubber bearings increase damping and reduce displacement demands. The study emphasizes the need for strong, flexible, and deformable structures to dissipate transient inputs. Additional dampers absorb energy, reducing stress and deflection. The research focuses on fluid viscous dampers using linear time history analysis for bridge applications.

II. LITERATURE REVIEW

1. M. C. Kunde and R. S. Jangid [1]. (Effects of Pier and Deck Flexibility on the Seismic Response of Isolated Bridges.) A study analyzed isolated bridges' seismic response using elastomeric bearings and sliding mechanisms with real earthquake ground motions. Different mathematical models yielded similar results, emphasizing the effectiveness of isolation systems in reducing earthquake impact on bridges.
2. Seyed Saman Khedmatgozar Dolati, Armin Mehrabi and Seyed Sasan Khedmatgozar Dolati [2]. (Application of Viscous Damper and Laminated Rubber Bearing Pads for Bridges in Seismic Regions)Study investigates the use of VD-LRBPs (viscous dampers and laminated rubber bearing pads) in reducing bridge displacement during earthquakes. Results show VD-LRBPs effectively decrease residual displacement, facilitate self-centering, minimize force transfer to the foundation, and dissipate seismic energy. Promising potential for seismic zones.
3. Li Zhen, Li Dejian,Peng Leihua, Lu Yao,Cheng Kepei and Wu Qianqiu[2]. (Study on the damping efficiency of continuous beam bridge with constant cross-section applied by lead rubber bearings and fluid viscous dampers.) Modifying seismic properties impacts multi-span bridge responses. Achieving effective isolation in both horizontal directions is challenging. Lead rubber bearings provide insulation and energy absorption, while fluid viscous dampers dissipate seismic energy. However, lead rubber bearings have limited horizontal resistance under severe earthquake loads due to decreasing stiffness after yielding.
4. CSiBridge Bridge Superstructure Design IRC-2011[6]. CSiBridge is a comprehensive software for bridge modeling, analysis, and design, capable of handling various bridge types. It automates design tasks based on load patterns, but users need to verify results and address other design aspects not covered by the software. Results can be visualized graphically and printed with customized reports, enhancing the bridge superstructure design process.
5. IRC 2011, IS 1893, and IRC 84 ,IRC83 & SP-114(2018). The literature review covers four Indian codes relevant to highway and bridge design. IRC 2011 guides highway bridge design with earthquake-resistant provisions. IS 1893 is the standard code for seismic design, including seismic zones and analysis. IRC 84 provides rural bridge design standards, including earthquake resilience. IRC 83 focuses on elastomeric bridge bearings, detailing material properties, design criteria, testing, and inspection.

III. LAMINATED RUBBER BEARING AND FLUID VISCOUS DAMPER

High density rubber bearing (HDRB) is another type of elastomeric bearing which consist of thin layers of high damping rubber and steel plates in alternate layers. The rubber used is either natural rubber or synthetic rubber which provide a sufficient amount of damping.

IX. ACKNOWLEDGEMENT

The authors thank  Dr DI Narkhede and the Head of the Department of Civil Engineering for providing the necessary facilities and guidance to complete the work successfully.

Conclusion

This study examined the effectiveness of VD-LRBPs (Viscous Dampers combined with Bearing) in controlling large displacements between the superstructure and substructure during Elcentro earthquakes in the transverse direction. Detailed FEM modelling, vehicle simulation, and dynamic analysis were conducted. The results showed that the combination of rubber bearings and viscous dampers increased flexibility and reduced the bridge\'s response to seismic excitation. The addition of viscous dampers also reduced axial forces in most cases but increased shear values, which could be mitigated by additional damping from the bearing and FVD. The exponential damper with ?=1 was found to effectively control displacements, providing a simple methodology for selecting optimal damper characteristics. Transverse moments in the column were reduced, particularly in the NS component. The shift in fundamental time period increased the bridge\'s flexibility, and the base shear of the bridge structure was significantly reduced after isolation.

References

[1] Shock vibration control of structures using fluid viscous dampers dr. D. I. Narkhede & R sinha(2012) [2] Effects of pier and deck flexibility on the seismic response of isolated bridges m. C. Kunde1 and R. S. Jangid (2006). [3] Study on the damping efficiency of continuous beam bridge with constant cross-section applied by lead rubber bearings and fluid viscous dampers li Zhen (2020) [4] Application of viscous damper and laminated rubber bearing pads for bridges in seismic regions Seyed Saman Khedmatgozar Dolati (2021). [5] Seismic performance of box girder bridge with non-linear static pushover analysis nilanjan tarafder1 and l.v. Prasad m.2(2018) [6] Csibridge® bridge superstructure design.(2020) [7] Seismic risk assessment of RC bridge Anandh C.S.1, Ajisha r(2018). [8] Pacific earthquake engineering research( peer ) data for ground motion.(2023) [9] Pre-test analytical studies of NEESR-SG 4-span bridge model using opensees. By M. Sadrossadat zadeh m. Saiid saiidi(2007). [10] Seismic design of a prestressed concrete bridge Alperen Ozel 2016 [11] Displacement based seismic assessment of existing bridges in regions of moderate seismicity by Bimschas, Martin. (2010)

Copyright

Copyright © 2023 Lt Col Mahesh Uniyal. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.