AREMA Guidelines BRIDGES.pdf

1 project report on use of special steel for girder bridges on indian railways submitted by sushil kumar yadav dyce n c rly course no 724 under the guidance of 2 contents page no 1 introduction 1 2 advantage of steel in bridge construction 1 3 need for special steel on ir 4 3 1 high strength structural steel 7 3 2high performance steel 8 4 properties of hps 10 5 recwnt developments in hps 11 6 arema guidelines 12 7 case studies 13 8 conclusions 19 9 suggestions recommendations 19 10 references 20 3 there are about 1 20 000 bridges of all types and spans on indian railways making an average of two bridges per route km a rough break up of the total is girder bridges 20 arch bridges 19 slab culverts 23 pipe culverts 19 other types 19 about 50 of these bridges are more than 100 years old though more than 1000 bridges are rebuilt rehabilitated every year the backlog is enormous old railway bridges are facing following types of problems aging and fatigue consideration increased loading standards for axle load increased longitudinal loads rebuilding meter gauge bridges for broad gauge work replacement of early steel girders provided prior to 1905 corrosion problems in coastal areas most of the girder bridges are of steel some of them being of early steel with heterogeneous composition and need constant attention for their upkeep early steel girder bridges are those bridges which were constructed before 1905 in those times the content of sulphur and phosphorus in the steel was more than the present day value more content of sulphur and phosphorus results brittle failure of the structures ministry of railways as a policy decision taken steps to replace all such bridges and accordingly any such scattered bridges if still existing on date has been planned to be replaced by 2008 under the special railway safety fund srsf there has been significant improvement in steel making technologies throughout the world over the last few decades both in terms of metallurgical advances and rolling and heat treatment process developments in spite of that indian railways has not revised their specifications for the steel to be used in the bridges the purpose of this paper to study the special steel being used world over and compare with the current practices of indian railways the steel is a very versatile material having many advantages over the other material presently the mega bridge projects being undertaken by the railways 4 involves steel super structures for longer spans the railway has shown more confidence in steel compared with psc this is basically due to the fact that in case of steel bridges rehabilitation procedures are easier and involve lesser delays inspections are easier as it allows the deformations to be seen and easily evaluated measured besides the basic fact that railway engineers feel comfortable in constructing and maintaining steel bridges generally speaking steel bridges may have the following advantages when compared to concrete psc bridges reduced dead loads more economic foundations simpler erection procedures shorter execution time faster and easier rehabilitation when constructed in insurgency affected areas like north east and j for hps 70w one with yield strength of 500 mpa and other with a yield strength of 700 mpa which are respectively called bhs 500 and bhs 700 additionally bhs 500w and bhs 700w indicate weathering type bhs the following are the applications of bhs in japan a the tokyo bay seaside road is routed to connect the reclaimed lands on the off shore side of the coastal road by constructing a bridge of 760 m in length across the sea bhs steel is proposed to be used for this bridge a truss bridge design and not a cable stayed bridge design is is adopted for this bridge having a central span of 440 m since the height under the girder is required to be large enough for a maritime transportation seaway under the bridge and at the same time the total height of the bridge is required to be low enough for the normal operation of haneda airport though the main material for the bridge will be bhs 500 bhs 700 will be applied to the truss members near the bridge piers where a large tensile force acts for rational utilization of the strength improved material the total quantity of steel to be used is of the order of 20 000 tons b a lot of bridges has been constructed in japan using nickel containing advanced weathering steel in the corrosion prone areas normally these steel contains 3 ni cu by applying these new steels the life cycle cost of these bridges are decreased as the cost of painting and repainting disappears for example the typical initial cost of heavy duty type painting is about 8 000 yen m while the initial additional cost of using these new steel is about 4 200 yen m so for only the initial painting cost these new steel can reduce the cost by about 50 and the life cycle cost benefit can be larger as the re painting cost in not needed a hybrid girder bridge sweden is simply supported with a span of 25 6 m and a free width of 7m the girder height is of 1245mm and the steel weight 103 kg m deck area the use of s690 has been done in the bottom flange the hybrid bridge girders are now included in the swedish bridge code b the road bridge over the river rhine at dusseldorf germany is a cable stayed road bridge of the highway a44 the bridge was built in thw period 1998 2002 for the steel structure 7180 t of steel grade s355 and 520 t of grade s460 were used c millau viaduct france is multiplan cable stayed bridge with a light steel deck crossing the river at a height of 270m with a total construction height of 343 m the bridge takes the world record of the highest bridge in the world the 2460 m long deck is composed of 6 main spans of 342 m each and two side spans of 204 m 19 each the deck is composed of a steel girder with a total height of up to 4 20 m and total width of 32 0 m in total 43 000 t of steel plates have been applied for the deck and pylons 12 500 t high strength steel grade s460ml has been used for the entire central box and some connecting elements with a thickness up to 80 mm in order to resist high load without increasing the amount of steel used reduce cantilever bending moments during launching of bridge apply a more efficient welding process reduced transport weights from the workshop to the site furthermore the pylons have been constructed in s460ml steel grade in a thickness of up to 120 mm fig 5 visualisation of the millau viaduct 20 fig 6 construction of boxes for the deck in progress millau viaduct fig 7 construction of the pylon millau viaduct 21 it is concluding that the high performance steel is being used on highway and railway bridges successfully all over the world because of its inherent quality of better strength resistance against fracture toughness weldability and a very good resistance against weathering corrosion the weight of the structure is reduced tremendously reducing the cost of substructure and foundations and over all reduced life cycle costs its introduction on indian railways will be a very good decision for the upgradation of the present technology of design fabrication and maintenance of steel bridges in comparison to the developed countries the steel being used in indian railways is of inferior quality following suggestions recommendations are given for early adoption of high performance steel over indian railways 1 furthermore studies should be conducted for the adoption of hps or any other type of steel which suits indian conditions and economy 2 the railway board in consultation with rdso may jointly discuss the issue for convincing the steel industry including sail for producing the special type of steel for indian bridges 3 a pilot project should be given to each railways for applying the high performance steel in at least one bridge so that experience in the same can be gained 4 the major supplier of hps in us and europe is arcelor mittal steel and corus group recently tied up with tata steel and they have a very good indian connection these groups may be approached for their help and guidan