RAILWAY BRIDGE MONITORING

8/7/2019 RAILWAY BRIDGE MONITORING

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RAILWAY BRIDGE MONITORING

PRESENTED BY

VINEESH K P

10ME63R38


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CONTENTS

OBJECTIVE OF MONITORING

STEPS IN MONITORING

MONITORING TECHNIQUES


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MONITORING OBJECTIVES

Structural assessment

Performance monitoring

Post strengthening monitoring Life time prediction monitoring


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STRUCTURAL ASSESSMENT

Monitoring stress, strain, displacement and

acceleration for assessing the globalbehaviour of the bridge.

Monitoring of local strains for assessing the

critical spots against fatigue.

Monitoring of temperature for assessing the

real temperature profiles and their effect on

the bridge.


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PERFORMANCE MONITORING

The goal of performance monitoring is to

assess the current performance of a bridgewith respect to serviceability condition.

POST STRENGTHENING MONITORING

Goal is to verify the effectiveness ofstrengthening action.


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LIFE TIME PREDICTION MONITORING

Collect real life data that contribute to

estimate the residual life time bridge.


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STEPS IN MONITORING


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DATA ACQUISITION


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DATA ACQUISITION

It deals with the installation of various sensing

elements that can measure the following

Strain Accelerations

Displacement

Temperature


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DATA ACQUISITION

FUNCTIONS OF SIGNAL CONDITIONER

1. Amplification of low level signal.

2. Filtering. Removal of unwanted signal received by the

signal.


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DATA ACQUISITION

DATA ACQUISITION BOARD

Convert the analog signal into digital signal.


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COMMUNICATION OF DATA

It refers to the conveyance of data from the

data acquisition system to the location where

the data is processed.


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DATA PROCESSING

A data processing step is defined by an

algorithm which transform one or more input

data into one or more output data.

It is important that process the data from all

sensors and relate it to a common reference.


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STEPS IN DATA PROCESSING

SPECTRAL ANALYSIS

Decompose the time series into frequency

components.


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STEPS IN DATA PROCESSING

DATA REDUCTION

Data reduction should be considered for every

measurements that needs to be sample with ahigh sampling rate.

METHODS OF DATA REDUCTION

Data compression Data transformation

Data evaluation


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STORAGE AND DIAGNOSTICS

Storage of processed data

Conversion of processed data into quantities

that relate directly to the response of thestructure.


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MONITORING

PERIODIC MONITORING

CONTINOUS MONITORING


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MONITORING TECHNIQUES

VISUAL INSPECTION

Accuracy of inspection depends upon

inspectors experience and skill time- and labour-consuming job

No information about the behaviour of the

strctuture due to dynamic loading.


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MONITORING THROUGH AMBIENT VIBRATION

To determine the vibration characteristics of a

structure excited by wind or human activity or

passage of train

Response is measured by accelerometers

Used for determination of natural frequencies,

structural damping, mode shapes, Damage

detection


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AMBIENT VIBRATION TEST


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AMBIENT VIBRATION TEST


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FREE VIBRATION TEST

It is based on sensing the accelerations of a

freely vibration structure.

The free vibrations can be generated by a train

or releasing the structure from a deformedstructure.

The accelerations data can be used for

extraction of natural frequencies,determination of structural damping and

mode shapes.


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LINEAR EXCITER TESTING

The structure is forced to vibrations by an

exciter, which moves a mass in vertical or

horizontal directions.

The inertial forces of the mass produces

reaction forces on the bridge.

The exciter force and the vibration response of

the structure at different positions are

captured with accelerometers


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LINEAR EXCITER TESTING

It can be sued for determination of natural

frequencies, structural damping, mode shapes

and transfer functions.


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ROTATING UNBALANCED EXCITER TESTING

The structure is forced to vibrations by an

exciter with a rotational mass with

eccentricity.

The centripetal forces of the rotating mass

produce a harmonic reaction forces on the

bridge.

The frequency of the harmonic force is given

by the rotation speed.


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ROTATING UNBALANCED EXCITER TESTING

It can be sued for determination of natural

frequencies, structural damping, mode shapes

and transfer functions


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REFERENCES

O.S.Salawu and C. Williams,Review of full scale dynamic

testing of bridge structures,Journal of engineering

structures,1995, Volume17,113-121

L.Fryba and M.Pirner,Load test and modal analysis of bridge,Journal of engineering structures,2001,volume 23,102-109.

Monitoring guide line for railway bridges,

www.sustainablebridges.com

Guideline for structural monitoring

www.sustainablebridges.com


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THANK YOU

RAILWAY BRIDGE MONITORING

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