ASSESSMENT OF RESIDUAL LIFE OF GIRDERS OF BRIDGE No

Ministry of Railways
Government of India
ASSESSMENT OF RESIDUAL LIFE OF GIRDERS OF BRIDGE
NO. 73 & 75 (ABANDONED), VASAI CREEK BRIDGES ON
BORIVALI – VIRAR SECTION OF WESTERN RAILWAY
REPORT NO. BS –79
MAY 2006
RESEARCH DESIGNS AND STANDARDS ORGANISATION
MANAK NAGAR LUCKNOW-226011
1

PREFACE
Whenever, a bridge is abandoned due to its weak substructure or some
other reasons before completing its codal life, it is important to know the residual
fatigue life of girders of its superstructure. If substantial life is still left, these
girders can be used on other routes. If the traffic density of such routes are
lower, these girders can be used for much more life span. Bridge No. 73 & 75,
known as Vasai creek bridges of Mumbai Central–Virar section of Mumbai
Division of W. Railway were abandoned due to their weak substructures after
completing about 66 years of service life and may have still, some useful life.
For estimation of the residual fatigue life of the girders by using S.N. curve
Approach, apart from the of stress- cycles (S.N.) curve of the material, the
stress-time history for the present day traffic passing over the girders is
essential, which is not possible to be obtained in case of above bridges, as the
bridges have been abandoned primarily due to weak sub–structure. For such
situation, the provisions of para. 9.2&9.3 of BS code 5400 part-10 are used for
assessment of residual fatigue life of these bridges. However, for more realistic
results, S.N. curve has been developed by fatigue testing of some samples
taken out from the existing girders. The S.N. curve, so developed, has been
used for assessing the residual life of the girders, by the method using damage
calculation.
For this work, a test team of S/Shri Ramji lal, SRE and S.K. Awasthi,
JRE-1 under the guidance of Sh. S.C.Gupta, Director/B&S/Testing was
constituted. The assessment of the residual fatigue life of the girders is done by
this team.
Fatigue testing of the samples was conducted by the staff of Fatigue
Testing Lab., under the guidance of Shri Mohan lal, SRE.
Contribution of all the team members in assessment of residual life
of the girders is highly appreciated. Guidance provided by Shri S.C. Gupta, to
the team members was worth appreciating, and sincerely acknowledged.
This report is submitted herewith for further necessary action to Executive
Director ( Works), Railway Board, New Delhi.
2
( LALLOO SINGH )
Executive Director/ B&S

INDEX
S.No Contents Page no.
1. Introduction 1
2. Objective 1
3. History of the bridge 1
4. Methodology 2
5. Estimation of residual fatigue life 7
6 observations 10
7. Conclusions
TABLES
11
1 RU Loading: Annual traffic tonnage for standard traffic
types
12
2 Details of fatigue testing of specimen taken out from
girders of existing abandoned bridge
13
3 Details of past traffic passed ( GMT ) between BCT-VR
14
section
1
FIGURES
Test specimen for fatigue testing 15
2 S-N Curve 16
3 Bar chart of traffic density between BCT-VR section during
1950-96
17
3a Cumulative Increase in traffic density since 1950-96 17
4 Histogram of computed stress cycles with different stress
ranges for light traffic and traffic density of 27 GMT
18
5 Graph of residual life and traffic density 18
ANNEXURES
I Copy of the letter from Exe. Director ( Works ) Rly. Board
for assessment of Residual life of Bridge No. 73
( Abandoned ) near Mumbai
II Calculation sheet for maximum stress range 24
III References 26
ASSESSMENT OF RESIDUAL LIFE OF GIRDERS OF BRIDGE NO. 73 & 75
(ABANDONED), VASAI CREEK BRIDGES ON BORIVALI – VIRAR SECTION
OF WESTERN RAILWAY
3
19

1.0 INTRODUCTION:-
Vide Executive Director ( Works) , Railway Board’s DO No. 2004/WI /WR/
Girder dt. 30.04.04, Member Engineering desired that a study may be
conducted to assess the residual life of the girders of the bridge No. 73 &
75 (Abandoned). With a view to use them on new branch line where the
traffic is going to be light in the beginning. The copy of the above letter
alongwith a report prepared by Western Railway on this issue is placed at
Annexure – I.
2.0 OBJECTIVE:-
To assess the residual life of the girders of bridge No. 73 & 75 Mumbai
division of W.R.
3.0 HISTORY OF THE BRIDGES:-
The bridge No. 73 & 75 (abandoned) are located on Basai Creek between
Bhainder and Naigaon stations of Borivali – Virar suburban sections of
Western Railway. The abandoned bridges were open to traffic on
22.01.1927. There are 69 x 2 = 138 nos. of 18.3 m span steel plate
girders on bridge No. 73 and 25 x 2 = 50 nos. of 18.3 m span girders in
bridge No. 75. Thus, there are 188 nos. girders of 18.3 m effective span.
There 8 nos. of 6.1 m span girder in bridge No. 73 & 75. The details of the
girders are as follows:
a) Effective Span - 18.3 m
b) Overall length - 18.95 m
c) Loading Standard - BG standard of 1916
d) Drawing No. - CEN/57728/11-D
e) Manufactured by - M/s P& W Maglellan Ltd., BB & CI. Co. -
1923, Clutha Works Glasgow.
The bridges were abandoned primarily due to Weak foundation and
overstressed sub-structure, where stresses were found to be exceeded
permissible limits, requiring heavy speed restrictions. Many CI piles were
cracked and were continuing in service on clamps. there was heavy
incrustation in the piles due to marine growth and same indicated
extensive loss of section. But the most important and critical reason was
that due to heavy sand dredging in the creek, the bed level gone down by
2.45 m since 1927 and pile grip in rock was reduced to near unsafe limits
in some cases.
In replacements of these bridges, new bridges were constructed on well
foundations at an average depth of 29 m below the mean tidal level and
PSC box type girders of 1.20 m + 28 x 48.5 m spans in bridge No. 73 and
4

11x 48.5 m spans in bridge No. 75 were constructed and open to traffic in
the year 1993 and since than the bridges of steel plate girders have been
abandoned.
4.0 METHODOLOGY:
For assessment of residual life of the girders of the bridges, the procedure
as given in BS – 5400 part – 10 , code of practice for fatigue has been
followed. The procedure given in clause 9.0 of the above code for railway
bridges has been used. Two methods for fatigue assessment of railway
bridges are given in clause 9.2 & 9.3 of the code. In method –1,
assessment is done without damage calculation and in method –2,
damage is calculated by using Miner’s summation rule. Both these
methods have been used for the assessment of residual life.
4.1 Method – 1: Fatigue life assessment without damage calculations:
4.1.1 General:
BS-5400 part 10 is a comprehensive code which is based on the concept
of cumulative fatigue damage. The fatigue assessment is based on
Palmgren-Miner’s damage summation model. For fatigue assessment of
railway bridges, the methodology for determination of stress range has
been described for different type of connections and a simplified
procedure has been given for determining the limiting value of the
maximum range of stress for the specified design life for two different
types of standard loadings. Details of RU loading ( Ref; Table- 1) has
been used for calculating the remaining fatigue life, as it is more severe
than IRS MBG loading. As per code, RU loading allows for all
combinations of vehicles currently running or projected to run on railways
in the Continent of Europe, including the United Kingdom and is to be
adopted for the design of bridges carrying main line railways of 1.4 m
gauge and above. The nominal type RU loading consists of four 250 KN
concentrated loads preceded and followed by a uniformly distributed load
of 80 KN/m The code specifies different factor k1, k2, k3, k4 & k5 for design
parameters such as design life, multiple cycle of stress loading, type of
standard loading, annual GMT and multiple lane loading respectively.
The code gives specific methodology and tables to calculate the factors
for different design parameters.
4.1.2 Limiting Stress Range, σT
The constant amplitude non-propagating stress range, σ0 for the
constructional detail is chosen appropriately on the basis of Table – 17 &
Table 8 of the code. The limiting stress range σT is calculated for RU
loading as under:
5

σT = k1. k2. k3. k4. k5. σ0 ……………………………………………………..(1)
Where, k1, k2, k3, k4,& k5. Are different parameters can be obtained from
the code.
4.1.3 Check for Design Adequacy:
The design adequacy of the given detail is checked as per Clause 9.2.2.2
and Clause 9.2.2.3 of the code. Where σRmax (Maximum Stress Range)
should not exceed σT, i.e σRmax < σT, the detail may be considered to have a
fatigue life in excess of the specified design life.
4.1.4 RU Loading & IRS-MBG Loading:
A comparison of EUDL values of Bending Moment as per RU loading has
been made with corresponding values for IRS-MBG loading and it is found
that the EUDL values as per RU loading are on higher side as compared to
IRS-MBG loading. Therefore, the various factors developed for RU loading
as given in BS: 5400 Part 10 have been used for fatigue life analysis of the
members of the bridge subjected to MBG loading which is expected to give a
fatigue life on a conservative side. But on the other hand it does not reflect
exactly the loading spectrum under Indian conditions, so the reliability of
results may not be as accurate.
4.1.5 Fatigue life analysis:
The stresses calculated during the analysis and the cross sections provided
in the existing design have been used to workout the fatigue life of the
girders.
Following assumptions have been made during this study –
a) The maximum axial stresses due to EUDL for IRS loadings have been
worked out and the maximum stress range calculated as the difference of
dead load stress and the maximum stress likely to come on the girder with
dead load, live load with impact and occasional load. The calculation
sheet for maximum stress range likely to occur on the girders is shown in
Annexure-II
b) The axial stresses due to load combination with occasional load have
been taken into consideration to find out the maximum stress range. This
combination rarely occurs in practice, therefore, the analysis is on
conservative side.
c) Material properties are assumed to be as per Table-8 of BS-5400 and σ0
value has been taken to be corresponding to detailed classification ‘D’ of
this table. This assumption may not be correct, but can be relied for rough
estimation.
6

d) The fatigue life of standard spans has been assessed by calculating the
design life factor k1. This factor has been worked out as σRmax/(σ0 x k3)
and fatigue life calculations have been done by inversion, using the
equations given in Clause 9.2.3 of BS-5400 Pt.-10 by taking fatigue life as
minimum of the following:
Fatigue Life
or
120
…………………………………………………………..(2)
m
k1
Fatigue Life
120
…………………………………………………………(3)
2
k
m
1
Where m = 3.0 taken from Table-8 for detailed Class ‘D’.
e) Value of RU loading factor k3 has been taken from Table-4 of the code
considering the case of heavy traffic loading, corresponding to the base
length (L) of the influence line diagram for the girder.
f) Value of GMT factor, k4 is assumed as 1.0 for GMT of 18 to 27 million
tonnes. Actual GMT data suggests that this assumption is very much on
conservative side.
g) For single lane loading value of lane factor, k5 is taken as 1.0.
4.2 Method-2: Fatigue life assessment with damage calculations :
4.2.1 General : This method involves a calculation of Miner’s summation
and may be used for any detail for which S-N relationship is known for any
known load or stress spectrum. This method may be used as a more precise
alternative to the simplified procedure as described in para. 4.1of this report.
The essential information which is required to assess the fatigue life of a
structure is the pattern of stresses likely to be observed in it, during the
passage of normal traffic and the relationship between the applied stress
cycles and the number of times these can be withstood by the material of the
structure. This can be achieved by subjecting the representative samples
not only to varying constant amplitude cycles or stresses but also to
complete stress spectrum. Using test results and curve fitting technique, S-N
relationship can be obtained. Under normal service conditions, Railway
bridge structures are subjected to spectrum of varying stress – amplitude
and therefore, a process of damage accumulation continues. The fatigue
damage depends on the combined effect of the frequencies of different
stress ranges, likely to be observed by the structure under service loading.
Referring to Palm-gren Miner’s theory of linear damage accumulation , the total
damage to the structure is given by D= ∑ ni/Ni.
Where , ni = Observed number of stress cycles for different stress
ranges
7

Ni = Theoretical number of stress cycles corresponding to
observed stress ranges from S-N curve.
i = 1,2,3 …. Upto n stress ranges
When the damage ( D) become equal to 1, the specimen fails and so the failure
occurs when D= ∑ ni/Ni. = 1
Many researchers have not been able to find good credence to this hypothesis.
The main reason is that a stress cycles causes different extent of damage
depending on its application on the material during its life. Research carried out
by ORE, under question D-128, has suggested that under assumption of normal
distribution of fatigue test data, the probability of failure by fatigue is considerably
low when the life is evaluated at two Standard deviations below 50 % probability
curve. To achieve this, the cumulative damage factor in the above equation is
taken as 0.3, where N is taken from mean S-N curve. Therefore, in our study
the criterion for fatigue failure is taken as D= ∑ ni / Ni = 0.3
4.2.2 S.N. Curve: The relationship between constant amplitude stress range
(Sre) applied to the specimen and number of cycles upto its failure (N) is called
SN Curve. Generally it is plotted on log-log scale with number of cycles in
millions on abscissa and stress range in N/mm 2 on ordinates. The slopping line
represents the finite fatigue life of the material. Mathematically SN curves are
defined in log-log form by the following equations:
Log N = Log a –M.Log Sre
Where, log a is the intercept on x-axis and M is the reciprocal of the slope of
the finite life portion of the SN curve. In normal form N is represented by the
following equation:
N = a / (Sre) m
4.2.3 Fatigue testing: Instead of using the S-N curve from the code for class
‘D’, Twelve numbers of specimen ( Six numbers each from top and web plate ) taken for
fatigue testing from the abandoned bridge No 73 girders for getting the actual fatigue
behavior of the material. The result of the fatigue testing can be used for bridge No. 75 as
the bridges are made up of similar material and are in operation on the similar times with
similar traffic. The specimens were tested for fatigue life in RDSO laboratory. The
specimen without holes were fabricated by welding end plates on either side of the
specimen as shown in fig.1. and subjected to fatigue test as per program of loading as
shown in table -2. The number of cycles at which the samples tested/failed is also shown
in the table. Sample designated as W-1 and B-1 were tested up to 10 million
cycles at the stress range 40 N/mm2 and did not fail even after completing 10
million cycles. Other samples were tested up to 2 million cycles due to some
higher load ranges and some of them failed before reaching 2 million cycles. The
higher values of load ranges are selected, so that the values of stress ranges
cover almost all the parts of the anticipated SN curve. The minimum load for
fatigue testing is taken as 30 KN for all the samples. It has been observed that
generally fatigue crack appears near the welding of end plates and propagates
8

slowly before failure, which shows the ductile nature of the material. The actual
values of cycles at failure with their corresponding stress ranges are plotted on
log-log scale. The best fit line, representing maximum number of points is drawn.
This line represents the SN curve for the material of the girder. The samples
which have completed 10 million cycles without failing are not considered for
plotting the best fit line as the samples were tested below the endurance limit.
SN relationship so obtained is shown in fig. 2 is used for calculating the residual
life of the girders. The values of constant a and M of the curve, calculated are
3.51 x 10 15 and 4.61 respectively. Therefore the equation of the curve is:
N = 3.51 x 10 15
(Sre) 4.61
or Log N = Log 3.51 x 10 15 - 4.61 log (Sre)
4.2.4 Stress spectrum: The number of different stress ranges are computed based
on maximum stress experienced by the girders as per MBG loading i.e., 96.25
N/mm 2 (Annexure-II) and reducing it proportionately up to the lowest range of
fatigue testing of the specimen taken out from of the existing girders. Although, it
is a plate girder bridge and stress range – cycle data of such bridges are not
available and hence to simulate with Indian railway conditions, the frequency of
the cycles are taken from the results obtained from the analysis of the stress-
time records of residual life estimation of Ganga bridge No. 110 up, an open web
girder near Kanpur, Lucknow division of N.R. As the observed stress range of
girders of the same bridge on down line is higher than the value of calculated
maximum stress range of this bridge, hence not considered for the residual life
calculations. Since the annual traffic density of this section is about 10 GMT at
the time of testing of the bridge and hence these values of stress cycles are
augmented by 2.7 times as at the time of closure of traffic on these bridges the
annual traffic density of this section was approximately 27GMT. The calculated
values of anticipated stress cycles for different stress ranges are shown below:
S No. Stress range in N/mm 2
9
No. of stress cycles
1 96.625-86.625 32
2 86.625-77.000 0
3 77.000-67.375 0
4 67.375-57.750 62
5 57.750-48.125 0
6 48.125-38.500 0
7 38.500-28.875 38
A stress histogram of the above different stress ranges and number of cycles
has been prepared and shown in Fig.-3.
4.2.5 Traffic Density and Speed:

Since the residual life calculations as per Miner’s summation rule are based on
the damage caused per day by the present day traffic and fatigue test conducted
on the specimen which have undergone different load cycles in the past, hence
the traffic passed in the past will not affect the residual life calculations. The
residual life calculations in this report for this methodology are based on annual
density of 27 GMT and hence, the traffic density increases/decrease in future,
the residual life will decrease/increase on prorata basis and will effect the
calculations. The details of traffic passed in GMT on the bridge during 1950-51 to
1995-96 is shown in table-3, fig.4 & 4a. On perusal of the table and figures , it is
seen that the traffic density which was 9.95 GMT in the year 1950-51, increases
to 27.15 GMT in the year 1992-93, the year in which the bridge was abandoned.
However, the maximum traffic density prior to 1976-77 was about 18 GMT and
increases thereafter up to about 27 GMT. Speed of the train also affect the
residual life of the girders, hence for calculation of maximum stress likely to be
observed on the girders, the impact factor has also been considered.
5 ESTIMATION OF RESIDUAL LIFE:
5.1 Assessment of residual life without Damage Calculation:
Following values of different parameters are considered for estimation of
residual life.
i) detailed class considered = D (from table 17 of code)
ii) Maximum stress range ( σT ) = 96.25 N/mm 2 (calculated)
iii) Constant amplitude stress (σ0) = 53 N/mm 2 (from table 8 of code)
iv) m = 3 (from table 8 of code)
v) k 2 = 1.0 by considering one stress range only
vi) k 3 = 1.92 (Heavy traffic) from table 4 of code
= 2.19 (Medium traffic)from table 4 of code
= 2.74 (Light traffic) “ “
vii) k 4 = 0.89 (42 to 27 GMT) from table 5 of code
= 1.0 (27 to 18 GMT) “ “
= 1.13 (18 to 12 GMT) “ “
vii) k 5 = 1.0 (for single lane loading) from table 6 of the code
Value of design life factor (k1) is calculated by the formula
σ T
k 1 = -------------------------------------------
k 2 . k 3 . k 4 . k 5 . σ0
5.1.1 For Heavy Traffic:
a) Traffic density 42 – 27 GMT
96.25
10

k1 = ------------------------------------------- = 1.063
1.92 x 0.89 x 53
Life = 120 / k1 m+2 = 88 years
Remaining Life = 88 – 66 = 22 years
b) Traffic density 27 - 18 GMT
96.25
k1 = ------------------------------------------- = 0.946
1.92 x 1.0 x 53
Life = 120 / k1 m = 142 years
Remaining Life = 142 – 66 = 76 years
c) Traffic density 18 - 12 GMT
96.25
k1 = ------------------------------------------- = 0.837
1.92 x 1.13 x 53
Life = 120 / k1 m = 205 years
Remaining Life = 205 – 66 = 139 years
5.1.2 For Medium Traffic:
a) Traffic density 42 – 27 GMT
96.25
k1 = ------------------------------------------- = 0.932
2.19 x 0.89 x 53
Life = 120 / k1 m = 148 years
Remaining Life = 148 – 66 = 82 years
b) Traffic density 27 - 18 GMT
96.25
k1 = ------------------------------------------- = 0.829
2.19 x 1.0 x 53
11

Life = 120 / k1 m = 211 years
Remaining Life = 211 – 66 = 145 years
c) Traffic density 18 - 12 GMT
96.25
k1 = ------------------------------------------- = 0.734
2.19 x 1.13 x 53
Life = 120 / k1 m = 304 years
Remaining Life = 304 – 66 = 238 years
5.1.3 For Light Traffic:
a) Traffic density 42 – 27 GMT
96.25
k1 = ------------------------------------------- = 0.745
2.74 x 0.89 x 53
Life = 120 / k1 m = 291 years
Remaining Life = 291 – 66 = 225 years
b) Traffic density 27 - 18 GMT
96.25
k1 = ------------------------------------------- = 0.663
2.74 x 1.0 x 53
Life = 120 / k1 m = 412 years
Remaining Life = 412 – 66 = 346 years
c) Traffic density 18 - 12 GMT
96.25
k1 = ------------------------------------------- = 0.587
2.74 x 1.13 x 53
12

Life = 120 / k1 m = 594 years
Remaining Life = 594 – 66 = 528 years
Calculated Residual Life of girders in different conditions are shown below:
S Traffic Type Residual Life in years for Traffic Density
.No.
42 – 27 GMT 27 – 18 GMT 18 – 12 GMT
1 Heavy Traffic 22 76 139
2 Medium Traffic 82 145 238
3 Light Traffic 225 412 528
5.2 Assessment of residual life with damage calculation: . It may be used as a
more precise alternative to the simplified procedure as described in para.5.1
above. This method involves a calculation based on Miner’s summation rule.
S.N. curve developed for limited number of fatigue testing of specimen taken out
from the existing girders and stress cycles are computed from the data as shown
in para 4.2.4 of this report. The calculation of residual life of the girders based on
the loading spectrum of the Ganga bridge for traffic density of 27 GMT, is shown
below:
Stress range in
N/mm 2
Mean Stress
Range in
N/mm 2
13
No. of cycles
per day
No. of cycles as
per SN curve X
10 6
96.250-86.625 91.4375 32 3.19
67.375-57.750 62.5625 62 18.16
38.500-28.875 33.6875 38 315.06
Damage per Year (D) =∑ (ni/Ni)
=[(32/3.19)+(62/18.16)+(38/315.06)]x10 -6
=0.005
Residual Life = 0 .3/D
= 60 years
6.0 Observations:
It is observed from the method of assessment of residual fatigue life, without
damage calculation that residual life of the girders is more conservative as the
minimum residual life calculated is 22 years for heavy traffic (42-27GMT) and the
maximum residual life is 528 years for light traffic (18-12GMT). However, based
on load spectrum as per Indian Rly’s traffic pattern the residual life as per
damage calculation method is 60 years for traffic density of 27 GMT. It seems to
be more realistic. The residual life, for lighter traffic conditions. By considering
the fact that the residual life varies inversely with the traffic density, the
relationship between residual life and traffic density can be drawn on log-log

scale ( fig.-5) and residual life for the actual operational traffic density of the
section, where these girders are likely to be used, can be obtained with the use
of this graph. Although, it is observed from the report prepared by the Railway
(Annexure-I) that many girders are having corrosion particularly in top flange
plates, but this factor is not considered in this study. Hence, it is advised that the
corroded parts of the girders should be replaced before their reuse.
7.0 Conclusions:
The girders of both the abandoned bridges can be used for traffic density of
27GMT for a period of about 60 years. With replacement of corroded parts, the
remaining life span of the girders can be extended further, if traffic density is less
than 27 GMT and good maintenance practices are being followed.
--------
14

15
Table –1
RU Loading : Annual traffic tonnage for standard traffic types
S
No
.
Traffic
Type
Train Type Train
Weight
(t)
No. of
Trains per
annum
Total
Tonnage
GMT
1 Heavy Heavy Freight 1120 4821 5.40
Heavy Freight 1120 7232 8.10
Mixed Freight 852 15845 13.50
Total 27.00
2 Medium Diesel Hauled Pass. Train 600 22500 13.50
Heavy Freight 1120 2411 2.70
Heavy Freight 1120 6027 6.75
Steel Train 1794 2257 4.05
Total 27.00
3 Light Steel Train 1794 752 1.35
Electric Multiple Unit 372 14516 5.40
Suburban trains 344 23546 8.10
Suburban Trains 172 47093 8.10
Diesel Hauled Pass. Train 600 4500 2.70
Electric Hauled Pass. Train 572 2360 1.35
Total 27.00
Table –2
Details of fatigue testing of specimen taken out from girders of
existing abandoned bridge no 73

Sl.
No
Specimen
designation
Stress
range in
KN
Load range in
KN
Min Max.
16
Frequency
In Htz
1. W-1 40 13.20 30.80 Between
10-15
No. of
cycles in
million to be
tested
10 or failure
which ever
No. of
cycles in
millions
tested upto
10 *
2. W-2 70 13.20 44.00 ----do----is
earlier.
2 or failure
which ever
is earlier
1.03
3. W-3 100 12.87 55.57 ----do----- -do- 2.12*
4. W-4 130 13.20 70.40 ----do----- -do- 0.25
5. W-5 160 13.20 83.60 ----do----- -do- 0.62
6. W-6 220 12.87 107.25 ----do----- -do- 0.03
7. B-1 40 18.24 42.56 ----do----- 10 or failure
which ever
is earlier.
10*
8. B-2 70 19.20 64.00 ----do----- 2 or failure
which ever
is earlier
0.84
9. B-3 100 19.20 83.20 ----do----- -do- 1.79
10. B-4 130 19.20 102.40 ----do----- -do- 1.18
11. B-5 160 19.20 121.60 ----do----- -do- 0.31
12. B-6 190 18.72 137.28 ----do----- -do- 0.11
* Samples not failed
Table - 3
Details of past traffic passed (GMT) between BCT– VR Section
UP DN

Year GMT during the GMT Cum. GMT during the GMT Cum.
Year
Year
50-51 9.95 9.95 9.95 9.95
51-52 5.96 15.91 5.96 15.91
52-53 6.03 21.94 5.03 21.94
53-54 6.23 28.17 6.23 28.17
54-55 6.33 34.5 6.33 34.5
55-56 7.16 41.66 7.16 41.66
56-57 8.15 49.81 8.15 49.81
57-58 8.62 58.43 8.62 58.43
58-59 8.63 67.06 8.63 67.06
59-60 8.64 75.7 8.64 75.7
60-61 9.59 85.29 9.59 85.29
61-62 9.27 94.56 9.27 94.56
62-63 9.8 104.36 9.8 104.36
63-64 10.14 114.5 10.14 114.5
64-65 11.21 125.71 11.21 125.71
65-66 12.08 137.79 11.78 137.79
66-67 12.9 150.69 12.1 149.59
67-68 13 163.69 12.3 161.89
68-69 11 174.69 11.5 173.39
69-70 11.7 186.39 11.49 184.88
70-71 10.92 197.31 10.54 195.42
71-72 12.13 209.44 11.83 207.25
72-73 18.72 228.16 18.1 225.35
73-74 18.34 246.5 17.86 243.21
74-75 16.49 262.99 16.71 259.92
75-76 18.39 281.38 17.64 277.56
76-77 19.06 300.44 17.31 294.87
77-78 23.81 324.25 25.1 319.97
78-79 25.69 349.94 25.05 345.02
79-80 23.55 373.49 23.17 368.19
80-81 23.38 396.87 22.25 390.44
81-82 22.8 419.67 21 411.44
82-83 22.43 442.1 21.7 433.14
83-84 22.92 465.02 22.43 455.57
84-85 22.66 487.68 20.87 476.24
85-86 23.53 511.21 20 496.24
86-87 24.32 535.53 23.27 519.51
87-88 27.17 562.7 26.14 545.65
88-89 28.14 590.84 28.3 573.95
89-90 24.43 615.27 22 595.95
90-91 25.42 640.69 23.51 619.46
91-92 27 667.69 25.88 645.34
92-93 27.85 695.54 27.15 672.49
93-94 28.22 723.76 27.2 699.69
94-95 28.65 752.41 28.76 728.45
95-96 28.69 781.1 29.52 757.97
Specimen for fatigue testing
17

All dimensions are in mm
18
Fig – 1

Stress range in N per sq mm
1000
100
Stress Range Vs No. of cycles
S-N Curve
10
0.100 1.000 10.000
No. of cycles in millions
19
Br. 73 DN
Fig. - 2
Traffic passed (GMT) between BCT– VR Section during 1950-96

Cummulative Traffic in GMT
Traffic in GMT
35
30
25
20
15
10
5
0
900
800
700
600
500
400
300
200
100
0
50-51
50-51
53-54
53-54
56-57
59-60
Traffic in GMT passed in the past
62-63
65-66
Cummulative traffic in passed in the past
56-57
59-60
62-63
65-66
68-69
71-72
68-69
71-72
Years
74-75
Years
20
77-78
80-81
83-84
86-87
89-90
92-93
95-96
Fig – 3
Fig – 3a
Computed stress cycles with different stress ranges for traffic
density of 27 GMT
74-75
77-78
80-81
83-84
86-87
89-90
92-93
95-96
UP
DN
UP
DN

No. of cycles
70
60
50
40
30
20
10
0
Traffic density in GMT
P.K. SANGHI
100
96.625-
86.625
10
86.625-
77.000
77.000-
67.375
21
67.375-
57.750
57.750-
48.125
Stress Range in N/Sq mm
Life Vs GMT
48.125-
38.500
38.500-
28.875
1
1 10 100 1000
Residual life in years
Fig – 4
Fig – 5
Annexure – I

EXEC. DIRECTOR (WORKS)
D.O. No. 2004/WI/WR/Girder New Delhi – dt. 30.04.2004
Dear Shri R. K. Gupta,
Sub: Alternate use of released steel girders of Vasai Creek bridges on
Borivali – Virar section of Western Railway.
On Borivali – Virar section of Western Railway, Bridge No. 73 & 75 across
Vasai Creek have been newly constructed. The old bridges built in 1916 have
been abandoned.
Member Engineering , has desired that a study may be conducted on the
residual life of the released girders of the old bridges and also the extent of
strengthening required with a view to use them on new branch lines where the
traffic is going to be light in the beginning. A report prepared by Western Railway
on this issue is enclosed herewith for considerations.
In view of the above, I would request you to take up the study and submit
report including cost of strengthening and loading standard permissible for these
released girders for further consideration of the Board.
With regards,
Shri R. K. Gupta,
Executive Director/B&S,
RDSO,
Lucknow.
22
Yours sincerely
Sd/-
(P. K. SANGHI)
Annexure
ABANDONED STEEL BRIDGE ON VASAI CREEK IN CCG – VR SECTION OF
MUMBAI SUBURBAN.

1. The Vasai Creek is spanned by bridge nos. 73 & 75 in CCG – VR section
of Mumbai Division on Western Railway. The Creek is in tidal zone, experiencing
rise and fall in water level but the riverbed is never dry.
2. HISTORY:
The abandoned bridge in question, which was in fact the second bridge,
was opened for traffic on 22.01.1927. The bridge was built 122 feet (36.5 m)
East of the first bridge. The bridge was designed to BG standard of loading
1916. The piers consisted of 6 nos. piles at 9 feet c/c spacing with 3 feet and 2.5
feet dia piles and had provision for future quadrupling . The substructure consists
of fish bellied plate girders of 60 feet (18.3 m) span. There were 69 spans in
south creek and 25 spans in north creek. There were 6.1 m span at either
approach of the two bridges.
The bridge was studied by RDSO in 1969 and was found to be weak in
foundation and the CI piles and bolts were found to be overstressed .
Subsequently, extensive field trials were conducted in association with IIT
Bombay and based on same construction of new bridge was included in railway
budget of 1981-82.
The reasons for abandoning the bridge were as follows:
a) The bridge being located on Bombay-Delhi Rajdhani trunk route, where
double heading of locomotive was essential, the bridge was not found to
be fit for normal speed. Even for the existing load, the foundation and the
substructure stresses were found to be exceeded permissible limits
requiring heavy speed restrictions.
b) A number of CI piles were cracked and were continuing in service of
clamps.
c) Due to standing water at all times at the bridge location, the foundation
could not be inspected thoroughly. There was heavy incrustation in the
piles due to marine growth and the same indicated extensive loss of
section.
d) The most important and critical reason was that due to heavy sand
dredging in the creek which was the most important source of sand for
Bombay peninsula, the bed level from 1927 had gone down by 8 feet
(2.45 m) and the pile grip in rock was reduced to near unsafe limits in
some cases.
In replacement of the bridge, new bridge was constructed on well
foundations at an average depth of 29 m below the mean tidal level and
PSC box type girders 65.10 m east of the second bridge and consisted of
1 x 20 m + 28 x 48.5 m PSC Box spans in bridge No. 73 and 11 x 48.5 m
PSC box spans in bridge No. 75. The bridge was opened to traffic in year
May 1993.
23

3. CONDITION OF STEEL GIRDERS OF BR.NO. 73 &75 (OLD)
3.1 The bridge No. 73 & 75 ( abandoned ) are located on Vasai Creek
between Bhainder and Naigaon stations of CCG – VR suburban
section. The old is located on the west most side of the existing bridge.
There are 69 x 2 = 138 nos. of 18.3 m span girders on bridge No. 73 and
25 x 2 = 50 nos. of 18.3 m span girders in bridge No. 75. Thus, there are
188 nos. girders of 18.3 m effective span. There 8 nos. of 6.1 m span
girder in bridge No. 73 & 75 which can not be reused since these have
already completed their fatigue life.
3.2 The details of girders are as follows:
a) Effective Span - 18.3 m
b) Overall length - 18.95 m
c) Height at end - 1.87 m
d) Height at center - 1.91 m
e) Flange width - 430 mm
f) C/C of girder leaves - 1.88 m
g) Loading Standard - BG standard of 1916
h) Drawing No. - CEN/57728/11-D
i) Manufactured by - M/s P& W Maglellan Ltd., BB & CI. Co. -
1923, Clutha Works Glasgow.
3.3 The girders of the bridge were inspected visually by Dy. CE (Br.) BL and
the following points were brought out:
The girders in the bridge can be classified into two broad categories
based on visual inspections:
a) Type I : The type I girders are having:
i) Corrosion in top flange plates upto 7 mm at sleeper seat locations i.e.
at every 65 cms spacing.
ii) 80 % gussets are having corrosion by minimum 4 mm, out of total 8
mm thickness. Many gussets are perforated.
iii) 30-35 % rivets have lost more than 50 % head due to corrosion in top
flange.
iv) Bracings are generally in satisfactory condition, except the end cross
frame top lateral angles, which are corroded and reduced in thickness.
v) There is slight corrosion in the bottom angle of main girder and the
same is generally OK.
vi) There is corrosion of upto 1 mm at the junction of the web plate with
bottom main angle.
24

vii) The girders are having sliding bearings i.e. girders are directly resting
on the bed plates with slotted holes in bottom flange having holding
down bolt through the same.
viii) All girders require painting.
b) Type II : The type II girders are having:
i) Corrosion in top flange plates upto 4 mm at sleeper seat locations i.e.
at every 65 cms spacing.
ii) 50 % gussets are having corrosion by minimum 4 mm, out of total 8
mm thickness. Many gussets are perforated.
iii) 15-20 % rivets have lost more than 50 % head due to corrosion in top
flange.
iv) Bracings are generally in satisfactory condition, except the end cross
frame top lateral angles, which are corroded and reduced in thickness.
v) There is slight corrosion in the bottom angle of main girder and the
same is generally OK.
vi) There is corrosion of upto 1 mm at the junction of the web plate with
bottom main angle.
vii) The girders are having sliding bearings i.e. girders are directly resting
on the bed plates with slotted holes in bottom flange having holding
down bolt through the same.
viii) All girders require painting.
3.4 Based on inspection, the girders pertaining to different spans have been
grouped as under:
I
II
Type Bridge No. Span No. Remarks
73
1 to 26 UP/DN, 31-33 UP/DN, 40 UP/DN, 41
UP, 42-43 UP/DN, 44 UP, 49 UP, 50 UP/DN,
51 DN, 52 UP, 55 UP/DN, 58 UP, 60 UP/DN,
62-64 UP, 65 UP/DN, 66 UP, 67 UP/DN, 68
UP, 69 DN, TOTAL : 88 GIRDERS
25
1. Span 14 UP has top flange
corrosion up to 10 mm &
perforation at places.
2. End cross frame bottom
lateral angle is perforated in
span 56 UP & 68 UP requiring
replacement.
75 2-18 UP, 20-25 UP, TOTAL : 23 GIRDERS -
27-30 UP/DN, 34-39 UP/DN, 41 DN, 44 DN, -
73
45-48 UP/DN, 49DN, 51 UP, 52 DN, 53-54
UP/DN, 56-57 UP/DN, 58 DN, 59 UP/DN, 61
UP/DN, 62-64 DN, 66 DN, 68 DN, 69 DN
TOTAL : 50 GIRDERS
75 1-25 DN, 1 UP, 19 UP, TOTAL : 27
DN line sleeper seat could not
GIRDERS
inspected due to track.
3.5 The recommendations based on inspections are :

a) The type I girders require replacement of top flange plate, all gussets and
corroded bracings along with provision of centralized bearings and
stiffening plates before use. All girders are require to be painted.
b) The type II girders require replacement of corroded gussets and rivets
and need based replacement of top flange at critical locations and
provision of centralized bearings and stiffening plates before use. All
girders are require to be painted.
3.6 The girders require the following prerequisites before the same can be
released for use elsewhere.
a) There is a water pipe line on bridge No. 75 provided on bracing between
girders of UP line and DN line for the inhabitants of the island between
bridges No. 73 and 75.
b) There is an H.T. electric line on bridge No. 75 provide bracing between
girders of UP line and DN line for the inhabitants of the island between
bridges No. 73 and 75.
c) The girders have lived part of the useful life in the period between 1927
and 1993 and the balance fatigue life is to be assessed for the section
where the girders are to be used.
-------------
26

WEIGHT CALCULATION
Calculation sheet for maximum stress range
27
Annexure-II
S.
No
Description
of Member
Size Sectional
Area
. mm
mm cm 2
Unit
Weight
Kg/m/cm 2
Length of
Member
Required
number
m
Weight
Kg
1 2 3 4 5 6 7
1 STIFFNER
2’=609.6 mm
2’7’’=787.4mm
3’8’’=1117.6mm
2 Stiffner Angle
5’=1524 mm
3 T-BAR
5’=1524mm
5’=1524mm
4 Stiffner Angle
5’=1524 mm
T-Bar
5’=1524 mm
5’=1524 mm
Main Angles
5 Top Flange
Angles
30’=9144mm
6 Bottom Flange
Angles
30’=9144mm
7 WEB PLATE
30’=9144mm
deduction due to
fish valley shape
Rectangular
shape
3’x1’5’’
Triangular shape
3’x4’7’’
8 Top Flange
Cover Plate
I st Top Plate
L=30’=9144mm
2 nd Top Plate
L=17’6’’=5334m
90x909x12
90x909x12
90x909x12
75x75x10
150x75x10
150x75x10
75x75x10
150x75x10
150x75x10
115x115x10
115x115x10
12.7x1524
12.7x914.4
1/2x12.7x914.5
508x15.8
457x15.8
20.19
20.19
20.19
14.02
19.96
19.96
14.02
19.96
19.96
22
22
193.54
-116.12
-58.06
80.26
72.23
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.7854
0.6096
0.6096
1.1176
1.524
1.524
1.524
1.524
1.524
1.524
9.144
9.144
9.144
0.4318
1.397
9.144
5.334
4
2
2
4
2
2
2
2
1
2
2
1
1
1
1
1
38.67
19.33
35.44
67.12
47.78
47.78
33.56
47.78
23.89
361.35
315.99
315.99
1389.95
-39.38
-63.7
576.4
302.59
9 Top Flange
Cover Plate
I st Top Plate
L=30’=9144mm
2 nd Top Plate
508x15.8 80.26 0.7854 9.144 1 576.4
L=18’6’’=5638m 457x15.8 72.23 0.7854 5.638 1 319.84
10 Web Splice 304.8x8 24.38 0.7854 1.295 3 74.39
4129.82
say 4130 Kg
Weight of 30 Feet Span = 4130.0 Kg
Weight of 60 Feet Span (single) 2x4130 = 8260.0 Kg

Weight of 60 Feet Span (double) 2x8260 = 16520.0 Kg
Add 2% for rivetting = 330.4 Kg
Total = 16850.4 Kg
Say = 17 t
Add 5% = 0.85 t
(4% for bearing and 1% for any missed member)
Total = 17.85 t
Say = 18 t
Track wt. 0.4 t/m = 7.58 t
Total = 25.58 t
Total Area = 503.35 cm 2
Deduction for rivets 4x2.54x1.0 = 10.16 cm 2
Net Area = 493.19 cm 2
Ixx = 1/12 x (508 x32 3 + 457 x 32 3 ) + 508 x 32 x (794 -16) 2
+ 457 x 32 x (794 -16) 2 + 1/12 x 10 x 1524 3 + 4 x { 2800000 + 2200
x (1524/2 - 33.2) 2 }
Ixx = 26328791605 mm 4
Ixx = 2.63287 x 10 10 mm 4
Ixx = 2.63287 x 10 6 mm 4
Y’ = 794 mm = 79.4 cm
Dead Load = 25.58 t
= 255.8 KN
DL+LL+IL = 2984.8 KN
B.M(DL) = WL/16 = 255.80 x 1000 x 1830/16 2.92571 x 10 7 Ncm
B.M(DL+LL+IL) = WL/16 = 2984.80 X 1000 X 1830/16 3.41386 X 10 8 Ncm
Stress(min) = BM(DL) x Y’/Ixx = 8822.33 N/cm 2 = 8.8233 N/mm 2
Stress(max) =BM(DL+LL+IL) x Y’/Ixx =10295.53 N/cm 2 = 102.9553 N/mm 2
Stress(T) = Stress(max) x A gross/A net =102.95 x 503.35 / 483.16 = 105.07 N/mm 2
Stress range = Stress(T) – Stress(min) = 105.07 – 8.82 = 96.25 N/mm 2
Effective length L’ = 18.3 m
28

REFERENCES:
29
Annexure – III
1. Estimation of the residual life of floor system of Ganga Bridge near
Balawali ( Civil Engineering Report No. 175 )
2. Investigations on the assessment of residual life of early steel/wrought
iron girder bridges ( Civil Engineering Report No. 245 )
3. Assessment of fatigue life of early steel/wrought iron girder bridges
( Report No. BS-5 )
4. Guidelines for assessment of residual life of early steel/wrought iron girder
bridges ( Report No. BS-39 )
5. Statistical distribution of axle loads and stresses in railway bridges
( ORE Report No.1 Question D-128 )
6. Fatigue life of riveted railway bridges by Bjorn Akesson, Chalmers
university of technology, Sweden .
7. Condition monitoring and life assessment of railway bridge 449/3/34 over
river Tapti near Bhusaval by Department of civil engineering IIT, Mumbai
8. Assessment of residual fatigue life of Ganga bridge near Kanpur, N. Rly.
( Report No. BS- 70 & 75 )
9. Code of practice for fatigue ( BS-5400: Part 10 )