View of A REVIEW STUDY ON CABLE STAY BRIDGE MODAL ANALYSIS

(1)

Vol.03, Issue 09, September 2018, Available Online: www.ajeee.co.in/index.php/AJEEE

1

A REVIEW STUDY ON CABLE STAY BRIDGE MODAL ANALYSIS Birendra Singh Punia¹, Prof. P.C. Diwan²

1Department of Civil Engineering, Swami Vivekanand University

Abstract: -The requirement of long span bridge is increase with development of infrastructure facility in every nation. Long span bridgecould be achieved with use of high strength materials and innovative techniques for analysis of bridge. Generally, cable supportedbridges comprise both suspension and cable-stayed bridge. Cable supported bridges are very flexible in behavior. These flexible systemsare susceptible to the dynamic effects of wind and earthquake loads. The cable-stayed bridge could provide more rigidity due to presenceof tensed cable stays as a force resistance element. There is stillplace for innovation in Cable-stayed bridge techniques. Here detail study of the cable stayed bridge is done. Historicalfacts, various components of the bridges, types of the pylon arrangements, type of the cable configuration arrangementshas been done to give a brief idea about cable stayed bridge from the various literature surveyed.

Keywords: cable-stayed bridge, dynamic load, suspension bridge, cable layout.

I INTRODUCTION

A cable-stayed bridge, one of the most modern bridges, consists of a continuous strong beam (girder) with one or more pillars or towers in the middle. Cables stretch diagonally between these pillars or towers and the beam. These cables support the beam. The cables are anchored in the tower rather than at the end.

The present trends of bridge design are aimed towards longer span but with slender and light weight structural forms. The structural development is based on an increased use of high- performance material. The cable-stayed bridges are a relatively new structural form made feasible within die combination of advances in material, construction technology and analytical capacities that took place largely within die last few decades. The cable-stayed bridge has become one of the most frequently used bridge systems throughout the world because of its aesthetic appeal, structural efficiency, enhanced stiffness compared with suspension bridge, ease of construction, greater resistance against aerodynamic action and economical substructure. A typical cable-stayed bridge consists of continuous girder with one or more towers erected in the middle of the span.

From these towers, inclined cables stretch down to support the girder.

Figure 1: Simple illustration of typical cable- stayed bridge

II. CABLES USED IN BRIDGES

Cables are one of the main parts of a cable-stayed bridge. They transfer the dead weight of the deck to the pylons.

These cables are usually post-tensioned based on the weight of the deck. The cables post-tensioned forces are selected in a way to minimize both the vertical deflection of the deck and lateral deflection of the pylons. There are four major types of stay cables including, parallel-bar, parallel-wire, standard, and locked-coil cables. The choice of these cables depends mainly on the mechanical properties, structural properties and economic criteria.

Cables are the fundamental elements in cable-supported structures.

For that reason, choosing among the different existing types requires special consideration. Cables are usually made of high tensile strength steel wires having a diameter ranging from 3 to7mm.

The general characteristics of the steel used:

 Yield strength: 1180 MPA

(2)

2

 Tensile strength: 1570 MPA

 Strain at breaking: 4%

 Modulus of elasticity: 205 GPA

 Chemical composition: 0.8% C, 0.2% Si, 0.6% Mn, 0.05% Cu, 0.05% Ni, 0.05%

 Cr, 0.03% P, 0.02% S.

This steel has a much higher yield stress and tensile strength than normal steel used in construction (about five times and four times higher values respectively), but a much lower ductility.

Due to its high carbon content, this steel cannot be welded.

2.1. Different kinds of cables

Different kinds of cables are manufactured and used. Each type has its advantages and it disadvantage and, most important of all, its unique area of applicability. It is up to the design engineer to choose the type and specification of the cable to be used on a particular project. The most common types of cables found in the market are:

 Parallel-bar cables

 Locked-coil strand cables

 Parallel-wire cables

 Stranded cables

A cable may be composed of one or more structural ropes or structural strands. A strand (with the exception of parallel wire strands) is an assembly of wires formed helically around a center wire in one or more symmetrical layers. A rope is composed of a plurality of strands helically laid round a core (see fig.2). The main differences between a strand and a rope are:

 At equal sizes, a strand has a greater braking strength than a rope.

 The modulus elasticity of a strand is higher than that of a rope.

 A strand has less curvature capabilities than a rope.

III. LITERATURE STUDY

G. Lakshmi et. al. (2017) This study deals with the study on optimization of cable stayed bridge with different cable configuration based on connection to the deck and the tower; and the different shapes of pylon (i.e. one axial layer of stays and two laterals of stays) up to failure and evaluates the most suitable configuration of the cable and the tower by using FEM software. The pylons are of

two laterals of stays i.e. ―A‖ shape,‖ Y‖

shape,‖ H‖ shape and one axial layer of stays i.e. circular shape pylon. All the considered shapes of pylon have cross sectional area but is of different shape.

The cable configurations are mainly of four types which are based on the connection of cables to the deck and the tower i.e. HARP configuration, FAN configuration, RADIAL configuration, STAR configuration.

Krunali Mavani et. al. (2017) This studied about the modelling of Cable Stayed Bridges with different pylon configuration. The cable stayed bridge is one of the modern bridges which were built for the longer spans. There is a need of study on the effect of shape of pylon on the dynamic response of cable stayed bridge, for this, the bridge span dimension and other parameters are kept constant, and only the pylon shape is varied i.e. A type, H type, inverted Y type, Single pylon, Diamond or Pyramid shapes

& Double Diamond or Spread Pylon shapes. The height of the pylon is also change for all the shapes for comparison purpose. The modelling of bridge is prepared on SAP 2000 software.

Mohamed Ghannam et. al.

(2017) studied the effect of post tensioned cables in strengthening double span steel trusses. Different truss’s systems (Warren and N truss system) are included in this study. Different techniques using post tensioned cables are used in strengthening different truss’s systems.

The main difference between these techniques is the profile and the locations of the post tensioned cables. Comparisons between these techniques are made in order to determine the suitable post tensioning technique for each truss system. The analysis and results are obtained by using ANSYS program.

Sukmata et. al. (2017) This study discusses the flutter speed of the cable stay bridge by means of numerical analysis as well as experimental.

Numerical analysis of flutter speed was conducted based on the eight extracted aerodynamic derivatives. the flutter margin method of Zimmerman was used to predict flutter speed of the experimental results. the analysis results showed that the critical flutter velocity based on the flutter derivatives was also confirmed by the experimental test

(3)

3 results. it is concluded that the result from numerical analysis is close to that of the experimental test.

Nguyen et. al. (2017) In this study, the finite element method (FEM) is used to investigate the dynamic response of CSB due to a three-axle vehicle considering braking effects. Vertical reaction forces of axles that change with time make bending vibration of the bridge deck increase significantly. The braking in a span is able to create response in other spans, towers, and cables. In addition, the impact factors are investigated on both FEM and experiment with a case study of Pho Nam bridge (Danang city, Central Vietnam). The results of this study provide an improved understanding of the CSB dynamic behaviors, and they can be used as useful references for bridge codes by practicing engineers.

HamidrezaNaderian et. al. (2016) This research provides a very efficient, integrated framework for seismic analyses of long-span cable-stayed bridges. The efficiency comes from the dramatic reduction in formation time and the degrees of freedom (DOF) associated with the structure, using the integrated finite strip method (IFSM) along with the application of a very robust and efficient time history method (THM) using the Newmark scheme for dynamic analysis of the bridge structure. The previous versions of the finite strip method are limited to modeling the bridge deck only, whereas other structural components are replaced by assumed boundary conditions. Using the IFSM, all components of the long-span cable-stayed bridge can be modeled in a unified system, and consequently, the real dynamic behavior including the interactions between deck, piers, and cables can be perfectly considered.

Firoz Abbasi et. al. (2015) In this study attempt is made to analyze long span cable-stayed suspension hybrid bridge. The suspension bridge could assign more span in the field of bridge.

So, combination of above two structural system the innovative form of cable- stayed suspension hybrid bridge could be the better option to provide more span.

some important structural concepts for cable-stayed bridge structure design as described. The towers are bent significantly as they are subjected to large

bending in the bridge structure. It needs additional cable acting the force on the opposite directions to balance the forces generated by the existing cables on the tower. There has an effective function for cable-stayed bridge to analysis load distribution flow, especially, understanding and research cable design on the bridge or other cantilever structures.

Hossein Ataei et. al. (2015) In this study, the effects of a hypothetical fire and the thermal gradient propagation along a pre-stressed cable is studied using non-linear Finite Element modeling and analyses. For this purpose, the possible fire intensities and durations are studied in order to determine their effects on the strength losses in pre-stressed cables using Finite Element Method.

Results of this research could be used as basis for investigation of structural failure of cable-stayed suspended systems.

Pengzhen Lu et. al. (2014) a simplified optimization calculation method of cable force for self-anchored suspension bridge has been developed based on optimization theories, such as minimum bending energy method, and internal force balanced method, influence matrix method. Meanwhile, combined with the weak coherence of main cable and the adjacently interaction of hanger forces, a simplified analysis method is developed using MATLAB, which is then compared with the optimization method that consider the main cable’s geometric nonlinearity with software ANSYS in an actual example bridge calculation. This contrast proves the weak coherence of main cable displacement and the limitation of the adjacent cable force influence. Furthermore, a tension program that is of great reference value has been developed; some important conclusions, advices, and attention points have been summarized.

M. M. Hassan et. al. (2013) In the study the response of a cable-stayed bridge to accidental breakage of any one stay cable is investigated. A comprehensive 3-D finite element model of the bridge is developed to provide realistic member internal actions. A 3-D cable element is utilized to represent the stay cables, and geometric nonlinearities are accounted for in the study. The static effect of loss of a stay cable on the

(4)

4 structural behavior of the deck is examined. The study builds on previously developed in-house optimization method for evaluating the optimum post- tensioning cable forces.

Bahareh Bannazadeh et. al.

(2012) this study has gathered more than 100 cable stayed bridges around the world in a table and has assessed them based on different parameters and has categorized these bridges in 3 categories of harp, fan and radial. This categorizing has been based on a relationship between the pattern of cables and the width of spans. Fundamentals of this categorizing have been defined in the first step of this paper. In continue the results have been represented. At the end the relationship between the width of span of these bridges and the category will be analyzed and the final conclusion will be presented.

Liuchuang Wei et. al. (2012) In this study is a single-tower double-cable- plane bridge, and the gulf nearby the bridge is in a typical typhoon-affected zone. Therefore, modal analysis of the cable-stayed bridge should be carried out.

In this study, based on the structural vibration theory and the theory of finite element model (FEM), the space FEM model of the cable-stayed bridge are established with APDL — ANSYS Parametric Design Language. Vibration mode and its frequency can be concluded by the calculating of the cable-stayed bridge’s FEM model.

IV. CONCLUSION

Cable-stayed bridges are beautiful structures. Their popular appeal to engineers and non-engineers alike has been universal. In a pure technical sense this bridge type fills the gap of efficient span range between conventional girder bridges and the very long span suspension bridges. Through these two different modelling structure designs which the half of combining harp and fan cable stays design and the whole combining harp and fan cable stays design, I found some important structural concepts for cable-stayed bridge structure design as described below:

 Tower material of cable-stayed bridge design is one important factor to keep a high-level stability for the structural body.

 It is quite significant for cable- stayed bridge design to estimate connection between cable stayed and tower with deck.

 The towers are bent significantly as they are subjected to large bending in the bridge structure. It needs additional cable acting the force on the opposite directions to balance the forces generated by the existing cables on the tower.

 There has an effective function for cable-stayed bridge to analysis load distribution flow, especially, understanding and research cable design on the bridge or other cantilever structures.

REFERENCES

1. G.Lakshmi Poornima, R.Bharath,

"Optimization and Analysis of Cable Stayed Bridges", International Research Journal of Engineering and Technology (IRJET), Volume 04, Issue 08, Aug -2017.

2. KrunaliMavani, Abhishek Raturi, "Dynamic Analysis of Cable Stayed Bridge for Different Pylon Configuration", International Journal of Advance Engineering and Research Development, Volume 4, Issue 11, November -2017.

3. Mohamed Ghannam, Nabil S. Mahmoud,

"Numerical Analysis for Strengthening Steel Trusses using Post Tensioned Cables", Global Journal of Researches in Engineering Civil and Structural Engineering, Volume 17 Issue 2 Version 1.0 Year 2017.

4. Sukmata, IrengGuntorojati, Fariduzzaman,

"Flutter analysis of cable stayed bridge", Sustainable civil engineering structures and construction materials, Elsevier, 2016.

5. Xuan-Toan Nguyen, Van-Duc Tran, "An Investigation on the Dynamic Response of Cable Stayed Bridge with Consideration of Three-Axle Vehicle Braking Effects", Hindawi Journal of Computational Engineering, Volume 2017, Article ID 4584657, 13 pages.

6. HamidrezaNaderian, Moe M. S. Cheung,

"Seismic Analysis of Long-Span Cable- Stayed Bridges by an Integrated Finite Strip Method", Journal of Bridge Engineering, 2016.

7. Firoz Abbasi, Sumeet Pahwa,"A Review and Analysis of Suspension Bridge Structures", International Journal of Science and Research (IJSR), Volume 6 Issue 2, February 2017.

8. Hossein Ataei, "Finite Element Analysis of Cable-Stayed Strands Failure due to Fire", Researchgate, 2015.

9. Pengzhen Lu, JiantingChen,Jingru Zhong,

"Optimization Analysis Model of Self- Anchored Suspension Bridge", Hindawi Publishing Corporation, Mathematical Problems in Engineering, Volume 2014, Article ID 403962, 8 pages.

(5)

5

10. M. M. Hassan, C.D. Annan, J-S. Matte,

―Finite Element Analysis of Cable-Stayed Bridges under the Effect of Accidental Loss of a Stay Cable‖, General Conference, CSCE, 2013.

11. BaharehBannazadeh, Zahra Sadat Zomorodian, Mohammad Reza Maghareh,

"A Study on Cable-Stayed Bridges", Applied

Mechanics and Materials Vols. 193-194, 2012, pp 1113-1118.

12. Liuchuang Wei, Heming Cheng, Jianyun Li,

"Modal Analysis of a Cable-stayed Bridge", International Conference on Advances in Computational Modeling and Simulation, Procedia Engineering, 31, 2012, PP. 481 – 486.