1

Seismic Protection of cable-Stayed Bridge Using Supplemental Devices

Guide By:- Prof. Hardik Solanki Sir M.Tech. (Structural Design)

Assistant Professor

Prepaid By:- Dhruv H Patel (140370720012)

PARUL INSTITUTE OF ENGINEERING & TECHNOLOGY

2

CONTENT

INTRODUCTION CLASSIFICATIONS POSITIONS OF THE CABLES IN SPACE OBJECTIVES IMPORTANCE OF STUDY LITERATURE REVIEW REFERENCES

3

INTRODUCTION

It is a bridge in which the weight of the deck is supported by a number of cables running directly to one or more towers. These bridges are very economical for long spans (over 100 meters), especially when access to the construction site is restricted.

4

INTRODUCTION Components of cable stayed Bridge and Load transmission

Tension

Compression

Slab Pile capCables Pylon Piles Soil

5

CLASSIFICATIONS

Based on arrangements of the cables• Harp arrangement • Fan arrangement • Semi-fan arrangement

Based on the shape of pylon• A-type• H-type• Y-type

6

CLASSIFICATIONS Based on arrangements of the cables

Harp arrangement The cables are made nearly parallel by attaching them to different points on the pylon.

Fan arrangement In this pattern, all the stay cables are attached to a single point at top of each pylon

Semi-fan arrangement combination of radial and harp types

7

CLASSIFICATIONS Based on the shape of pylon

8

Cable A cable may be composed of one or more structural ropes, structural

strands, locked coil strands or parallel wire strands. A strand is an assembly of wires formed helically around centre wire

in one or more symmetrical layers. A strand can be used either as an individual load-carrying member,

where radius or curvature is not a major requirement, or as a component in the manufacture of the structural rope.

A rope is composed of a plurality of strands helically laid around a core. In contrast to the strand, a rope provides increased curvature capability and is used where curvature of the cable becomes an important consideration.

Cables are made of high-strength steel, usually encased in a plastic or steel covering that is filled with grout , a fine grained form of concrete, for protection against corrosion.

9

POSITIONS OF THE CABLES IN SPACE Single Plane System

This type of system consists of bridges with only one vertical plane of stay cables along the middle longitudinal axis of the superstructure

10

POSITIONS OF THE CABLES IN SPACE Two plane system

Two Vertical Planes System In this type of system there are two parallel sets of cables and the tower on the either sides of the

bridge, which lie in the same vertical plane.

Two Inclined Planes System In this system the cables run from the edges of the bridge deck to a point above the centerline of the

bridge on an A-shaped tower or λ-shaped or diamond shaped pylon.

This arrangement can be recommended for very long spans where the tower has to be very high and needs the lateral stiffness given by the triangle and the frame junction.

Two Vertical Planes System

Two Inclined Planes System

11

OBJECTIVES

Study of mathematical model for three dimensional dynamic analysis and verification of standard software ( CSiBridge )

To investigate the performance of different structure control systems for the earthquake response control of a cable-stayed bridge.

12

IMPORTANCE OF STUDY

Because of the flexibility of cable stayed bridge, the deck experiences a large displacement response when subjected to dynamic loads such is earthquake and wind.

As a result, the connections between the deck and the tower of the bridge will reduce the deck displacement but increase the base shear of the towers. However, research on such type of loading is scarce

13

LITERATURE REVIEW Paper Titled:- Passive hybrid systems for earthquake protection of cable-stayed bridge Published in:- Science Direct Engineering Structures, Volume 29, Issue 1, January 2007,

Pages 57–70 Author:- B.B. Soneji,  R.S. Jangid

In simplified lumped mass finite-element model of the Quincy Bay-view Bridge at Illinois is used for the investigation

In this study object (i) to investigate the performance of different passive hybrid systems for the earthquake response control of a cable-stayed bridge; (ii) to investigate the influence of nonlinear viscous damping of the VFD on the seismic response of isolated bridge; and (iii) to arrive at the values of design parameters of the VFD that provide optimal response control of the isolated cable-stayed bridge.

Time History of Earthquake Used in study Imperial Valley 1940 ( EL centro), Kobe, 1995 (Japan Meteorological Agency), Loma Prieta, 1989 (Los Gateos Presentation Center), Northridge,1994 ( Sylmar Converter station)

The conclusion made The seismic isolation in the cable-stayed bridge helps to reduce the acceleration response and the base shear response substantially. However, the displacement response of the deck increases significantly with isolation. A passive hybrid system consisting of FPS and VFD is found to be more effective in controlling the peak displacement response of the deck.

14

LITERATURE REVIEW The cable-stayed bridge model

Finite Element model of towers

Positions of the VFD and Isolators

15

LITERATURE REVIEW Paper Titled:-Semi-active control of a cable-stayed bridge under multiple-support excitations Published in:- Civil Engineering , Journal of Zhejiang University Science, March 2004, Volume 5, Issue 3, pp 317-325 Author:- Dai Ze-bing , Huang Jin-zhi, Wang Hong-xia

This paper presents a semi-active strategy for seismic protection of a benchmark cable-stayed bridge with consideration of multiple-support excitations. In this control strategy, Magnetorheological (MR) dampers are proposed as control devices, a LQG-clipped-optimal control algorithm is employed.

Benchmark cable-stayed bridge is Cape Griardeau, Missouri, USA.

In comparing the active, semi-active and passive control systems, it was observed that similar performance could typically be achieved by all of these systems, reinforcing the result obtained by previous researchers that semi-active systems can achieve similar performance levels to that of active systems. In some cases the semi-active systems performed better than the active, while requiring significantly less power than the active system.

16

LITERATURE REVIEW Paper Titled:- Nonlinear dynamic behavior and seismic isolation of steel towers of cable-stayed

bridges under great earthquake ground motion Published in:- 12th World Conference on Earthquake Engineering, Auckland, New Zealand,

Sunday 30 January - Friday 4 February 2000. Author:- Toshiro HAYASHIKAWA, Yoshitaka MATSUI And Takakichi KANEKO

The nonlinear behavior of steel towers of cable-stayed bridges subjected to three-dimensional great earthquake ground motions is studied. Nonlinearities due to geometry changes and material sources of bridge tower elements are considered, and a tangent stiffness iterative procedure is used in the dynamic analysis to obtain the nonlinear seismic response.

The adoption of passive control systems can accomplish a significant reduction in seismic-induced forces, as compared to the case with no passive control device added.

The calculated results of the relationship between bending moment and curvature, it is considered that A-type tower is suitable in three tower shapes. As for H-type and gate-type tower, large inertia force acts on in-plane, so the hysteresis curve depends on the position of the horizontal beam. It is recognized from the axial force of the tower basement that the A-type tower is unsuitable tower shape because large compressive axial force and negative reaction force occur.

The passive control device by moving vertically is installed in the tower top of the cable stayed bridge to reduce the axial compressive force and the negative reaction force at the tower basement.

17

LITERATURE REVIEW

18

LITERATURE REVIEW

19

LITERATURE REVIEW Paper Titled:- Seismic behaviour of cable-stayed bridges: Astate-of-the-art review Published in:-4th International Conference on Earthquake Engineering, Taipei, Taiwan,

October 12-13, 2006 Author:- Galo E. Valdebenito and Angel C. Aparicio.

The seismic behaviour of cable-stayed ridges with special attention in the non-linear seismic behaviour, tower response and spatial variability effects. Incorporation of additional systems of passive protection and the use of new intelligent strategies based on hybrid and semi-active systems are the final part of this work.

Available data on near-field earthquakes indicate that vertical seismic motion can be greater than the horizontal one, and both jointly can become more than three or more times the design values. This denies the general recommendation that considers as maximum vertical effective acceleration, 2/3 of the maximum horizontal effective acceleration.

The passive protection of cable-stayed bridges, it seems that the effectiveness of the employed system strongly depends on the device used and its configuration, bridge geometry, earthquake nature and source distance. Aspects such as damping, effect of cable vibrations, influence of support conditions, soil-structure interaction and site-conditions, spatial variability effects and the seismic input are very important to the global response. The use of fluid viscous dampers, LRB devices and sliding dampers can be the future in relation to passive seismic protection.

The use of active devices is an attractive and interesting strategy for the seismic control of cable-stayed bridges. However, it is necessary a better comprehension of their behaviour and performance, specially their hysteretic characteristics and non-linear behaviour. In fact, the key for an adequate response is to benefit from a good control algorithm, low energy requirements andenough robustness.

20

LITERATURE REVIEW Paper Titled:- Seismic time history analysis for cable-stayed bridge considering different

geometrical configuration for near field earthquakes Published in:- World Academy of Science, Engineering and technology, Vol:7 2013-07- 25 Author:- Atul K. Desai

Study of mathematical model for three-dimensional dynamic analysis and verification of standard soft-ware. Commercially available software SAP: 2000, which was used by Abolhassan [1] is used for the analysis.

Preparation of three-dimensional geometrical computer models using longitudinally spread pylons (Y – Shaped pylons) Vs conventional A-shaped pylons for straight cable-stayed bridge.

Time History of Earthquake Used in study Bhuj Earthquake (2001,Gujarat,India), Koyna Earthquake (1967, Maharashtra, India), EL-Centro Earthquake ( 1940, California, USA)

For long span cable-stayed bridge, Option of Bi-stayed Bridge with intermediate side span gives lowest bending moment of pylon base, for all three seismic time histories.

Bi-stayed cable-stayed bridge has reduced cable forces and bending moment of pylon as compared to conventional cable-stayed bridge.

The seismic isolation using damper in the cable-stayed bridge helps to reduce the acceleration response and the base shear response substantially in all types of cable stayed bridges.

The study conducted here is useful to arrive at the best pylon shape and cable-anchoring system (self-anchored or bi-stayed) from dynamic point of view for any type of earthquake (viz- short, medium or long duration).

21

LITERATURE REVIEW Paper Titled:- Passive hybrid systems for earthquake protection of cable-stayed bridge Published in:- Science Direct Engineering Structures, Volume 29, Issue 1, January 2007,

Pages 57–70 Author:- B.B. Soneji,  R.S. Jangid

Study of mathematical model for three-dimensional dynamic analysis and verification of standard soft-ware. Commercially available software SAP: 2000, which was used by Abolhassan [1] is used for the analysis.

Preparation of three-dimensional geometrical computer models using longitudinally spread pylons (Y – Shaped pylons) Vs conventional A-shaped pylons for straight cable-stayed bridge.

Time History of Earthquake Used in study

22

REFERENCES B.B. Soneji,  R.S. Jangid, ” Passive hybrid systems for earthquake protection of cable-stayed bri

Engineering Structures, Volume 29, Issue 1, January 2007, Pages 57–70 dge”

Dai Ze-bing , Huang Jin-zhi, Wang Hong-xia,”Semi-active control of a cable-stayed bridge under multiple-support excitations”, Civil Engineering , Journal of Zhejiang University Science, March 2004, Volume 5, Issue 3, pp 317-325

Toshiro HAYASHIKAWA, Yoshitaka MATSUI And Takakichi KANEKO, “Nonlinear dynamic behavior and seismic isolation of steel towers of cable-stayed bridges under great earthquake ground motion” 12WCEE 2000 : 12th World Conference on Earthquake Engineering, Auckland, New Zealand, Sunday 30 January - Friday 4 February 2000.

Galo E. Valdebenito and Angel C. Aparicio, “Seismic behaviour of cable-stayed bridges: Astate-of-the-art review” 4th International Conference on Earthquake Engineering, Taipei, Taiwan, October 12-13, 2006

Atul K. Desai, “Seismic time history analysis for cable-stayed bridge considering different geometrical configuration for near field earthquakes” World Academy of Science, Engineering and technology, Vol:7 2013-07-25

23

Thank You