ASSESSMENT OF RESIDUAL LIFE OF GIRDERS OF BRIDGE No

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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
Page 1: Ministry of Railways Government of
Page 5 and 6: 11x 48.5 m spans in bridge No. 75 w
Page 7 and 8: d) The fatigue life of standard spa
Page 9 and 10: slowly before failure, which shows
Page 11 and 12: k1 = ------------------------------
Page 13 and 14: Life = 120 / k1 m = 594 years Remai
Page 15 and 16: 15 Table -1 RU Loading : Annual tra
Page 17 and 18: Year GMT during the GMT Cum. GMT du
Page 19 and 20: Stress range in N per sq mm 1000 10
Page 21 and 22: No. of cycles 70 60 50 40 30 20 10
Page 23 and 24: 1. The Vasai Creek is spanned by br
Page 25 and 26: vii) The girders are having sliding
Page 27 and 28: WEIGHT CALCULATION Calculation shee
Page 29: REFERENCES: 29 Annexure - III 1. Es

ASSESSMENT OF RESIDUAL LIFE OF GIRDERS OF BRIDGE No

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