Nerbudda Bridge
Built at Broach for the Bombay, Baroda and Central India Railway
Original Bridge
The BB&CIR main line, which included the first Nerbudda Bridge opened in June 1860.
1858 'EAST INDIAN RAILWAYS.
CONSTRUCTION OF BRIDGES AND VIADUCTS.
An exceedingly interesting and important test, in reference to the strength of iron railway bridges for Indian railways, took place yesterday, at the works of Messrs. Westwood Baillie, Campbell, and Co., London-yard, Isle of Dogs.
Colonel Kennedy, the chief engineer of the Bombay and Baroda Railway Company, has in a series of very able papers pointed out to the consideration of his directors, and those who are interested in the cheap and rapid construction of railways in India, the importance of completing a system under which all the bridges and viaducts should be carried out on a principle which will admit of the adaptation of the portions of any one of these structures to the repair or reformation of any other or all of them. In fact, Colonel Kennedy's system is that the bridges and spans of all his similar works shall be identical in their parts — a system which, if it had been applied to the construction of such works in this country and to the building of our locomotives, would have affected a saving of some hundreds of thousands per annum in the repairs of our permanent ways and rolling stock. There were present at the experiments of yesterday Major Crawford, consulting engineer of the railway department of the Bombay government; Mr. Walker, the managing director of the Madras Railway ; and Mr. Hayter and Mr. Cordon, assistant engineers of that line ; Mr. Yarrow, consulting engineer of the Scinde Railways ; Mr. Guerin, the inventor wthe self-acting railway-break; Messrs. Lloyd Foster, of the Wednesbury Iron Works, the manager of the Shelton Bar Iron Company ; Mr. E. Bray, a large contractor for work, on the Scinde Railway; Mr. Jeffries, of the Bengal army; Mr. Martin, engineer to the East and West India Dock Company; and a large number of other professional gentlemen.
The progress of the works at the London yard (Isle of Dogs), at which the experiments took place, is as interesting, in a commercial point of view as the success of the test to which the Indian iron bridge was subjected yesterday is of national importance. Some eighteen months since the eight acres on which the works of Messrs. Westwood Baillie, Campbell, and Co., have been erected, were simply brickfields. During the period mentioned the firm have erected an extensive range of workshops, in which are to be found all the conveniences of drilling machines, punching presses, lathes and, in fact, everything necessary for carrying on a large trade in shipbuilding, wrought-iron bridges, and other works. The firm have turned out, during the eighteen months, 2000 tons of iron bridges for the East Indies. They have completed other bridges and pontoons to the extent of 1000 tons, and constructed the landing pier at Milford Haven for the Leviathan, a work which has met with the entire approval of Mr. Brunel; they have built three vessels, a caisoon for the East and West India Dock Company, and 40 mud vessels for the Turkish government. These were turned out within two months, with other works, including a number of steam boilers, and we may further mention that the firm are now in the course of completing 4660 feet of iron bridges for the East Indian railways.
The bridge tested yesterday is of 60 feet span; it is elegant in structure, and its economy will be understood from the fact that the whole weight of it was within 21 tons. The entire load placed upon the bridge was 108 1/2 tons. .... deflection .....
The bridge of yesterday had reference to the Nerbudda bridge on the Bombay and Baroda line, and it was one of a series of test to which the parts of these structures are put as often as any large number of girders are prepared at the establishment. The mode in which the strength of these materials is tested is to select indiscriminately from the constituent portions of about 40 girders tbe portions necessary to make up one span, so that it amounts to a double proof, namely the strngth of the principal girders and the general accuracy of the workmanship of the whole of the materials. The result of the test of yesterday was precisely analogous with the results which we understand had preceded it. The load placed upon the bridge was double the weight that can possibly be placed upon it in the working of ordinary railway traffic. After taking the extreme deflection with the full load the waggons were removed and the bridge came back to its originalposition without any appreciable permanent set; a fact that is highly creditable to the manufacturers, inasmuch as the amount of permanent set usual in structures of this character may be fairly considered a measure of the perfection or imperfection of workmanship. We may observe, for the information of our scientific readers, that the "camber" before and after the experiment was precisely 2 1/4 inches. The party having satisfied themselves that there was not any permanent set in the structure, Colonel Kennedy ordered the workmen to withdraw the pin on the lower tension bar nearest to the pier, where the structure sustains the greatest strain, and upon a close examination it was found that the pin was not in the slightest degree strained. A great deal in reference to the progress of the railway system in India will probably depend upon the adoption of an economical system of constructing bridges and viaducts. Tunnelling and masonry to a very great extent regulate the periods in which railways, especially in India, can be carried out. The rivers of India offer the chief impediment to rapid construction. The principle adopted by the Bombay and Baroda Company is to manufacture both the superstructure and the piers of the bridges in the forges of England; and by the adoption of Warren's principle for bridges, and Mitchell's screw piles for piers, the least possible work has to be effected for placing theem in their position, and masonry is to the utmost possible extent dispensed with. If our memory serves us correctly that Mr. Kennedy stated at the last meeting of this company company that he would be able to complete the line at a cost little over 6000l. per mile, including bridges and viaducts.'[1]
25 of the 67 spans over the Nerbudda were swept away on 6 Sept 1876. The engineering staff of the Company immediately set to work to restore communication, and they succeeded in doing so on the 30 October by a diversion on a low level. They also applied themselves to repair the broken spans, and so well were their plans organized, that the bridge was finished and opened for traffic on 28 April 1877.
Description of the first bridge, from an article about the collapse in The Engineer, 1876[2] FALL OF THE NERBUDDA VIADUCT ....... The railway viaduct over the Nerbudda consisted of sixty-seven spans of generally 62½ ft. length, each supported upon cast iron columns or piles 2ft. 6in. external diameter, made up of 9ft. lengths. The total length of each averages between 80ft. and 90ft., and they are screwed into the bed of the river to depths varying from 30 ft. to 40ft. Each pier consisted of five of these piles ranged in a single row transversely to the viaduct, with here and there some extra piles supporting fenders for protection from the trunks of trees which are frequently floated down by the floods. The double line of rails is carried by longitudinal wrought iron lattice girders over the three central piles, and the weight is distributed over the five by cast iron cross girders. There is room left, therefore, on each side of the line for a platform or footway, but these, although at one time contemplated, have not been completed, and foot passengers usually crossed the river in boats. The piles are cross trussed down to and below the river bed, and the structure is very rigid.
First Replacement Bridge, opened 1881
A new bridge was specified, on different principles. Instead of being supported by screw piles, and having 67 spans, the new bridge would have only 25 spans, consisting of wrought iron girders, 187 feet 6 inches in length, supported by piers each formed of two iron cylinders. It was designed by Sir John Hawkshaw, and a contract was placed with Hopkins, Gilkes and Co. for the provision and delivery in India of all the ironwork.
The erection was supervised by Mr. H. B. Hargrave, under the general superintendence of Mr. Mathew, BB&CIR Agent and Chief Engineer.
The above information is largely condensed from the Wikipedia entry.
1881 From the Times of India, Wednesday 18 May 1881: 'THE OPENING OF THE NERBUDDA BRIDGE….. The completion of such a magnificent engineering work, as the new bridge of the B. B. and C. I. Railway, across the Nerbudda at Broach, is an event worthy of note, and the date which heads this communication will long be remembered, to use a trite phrase, as a red-letter day, in the annals of this quiet Guzerat town. .....
'.... It is a broad and beautiful stream at the point where the railway crosses it at Broach; but in days gone by it has proved itself a terrible tyrant, and the source of vast expense to the Railway Company, ....
'.... The old bridge, which consists of Warren girders of 60 feet span, supported on cast iron columns, 2 feet 6 inches in diameter, was built some 21 years since, and if it is remembered that at the early period of its conception, little experience had been gained as to the best way of dealing with rapid and deep Indian rivers, it must be admitted that the structure, on the whole, served its purpose well, and contended sturdily, and, all things considered, successfully against the mighty river which it spans. The rapid strides which the art of bridge-making, in common with every other department of engineering science, has made daring the past few years, opened the way to a material improvement in the method of bridging this river, and when in 1876, as many as 25 out of the total 69 spans of the bridge were carried away by a flood, the directors of the company determined to take advantage of the improvements within their reach, and construct a new bridge, which would, in all human probability, resist all the adverse influences of the current. With this end in view, a design for a new bridge was furnished by Sir John Hawkshaw, the eminent engineer, and finally approved of and it was to witness the formal opening of this bridge, that so many people gathered on the banks of the Nerbudda to-day.
'I am afraid that the description of such a prosaic and eminently useful work as a railway bridge is scarcely likely to prove interesting to such of my readers as peruse theme columns for amusement, especially as I shall be compelled, in referring to the bridge, to take extensive advantage of plain facts and figures kindly furnished me by a professional gentleman connected with the work ; but, I trust, that others, who take an interest in the completion of great works of science, will find both pleasure and profit in reading these details.
'The bridge piers, of which there are 26, consist of cast iron cylindrical columns built up in rings varying from 6 to 9 feet in length, each ring being formed of six segments, the whole strongly bolted together with 1¼ inch diameter bolts. The metal throughout is 1½ inch thick and 14 feet in diameter, for lengths varying from 33 to 57 feet, coming into 10 feet diameter throughout the remainder of their length. The lower part of the 14 feet diameter cylinders is formed for a length of 9 feet of wrought iron in three thicknesses of ½ inch plate terminated with a strong solid rolled cutting edge. The columns, when sunk to the required depth, were filled with strong hydraulic concrete, the water in every case being first pumped out before the concrete was put in position. Two of these columns placed at right angles to the length of the bridge, and at a distance of 37 feet 6 inches from centre to centre form a pier, and are connected on top by two strong box girders, weighing 21½ tons each, strongly secured to the columns by holding down bolts 2 inches in diameter. A second box girder 4 feet square, placed near high-water mark between the columns, and strongly bolted to them, acts as an additional stiffener to the pier.
'The piers are placed at a distance of 187 feet 6 inches centre to centre. 25 spans of superstructure cover these piers ; the class of superstructure adopted may be described as trusses with parallel booms, vertical struts, and inclined ties which cross three bays formed by the struts, or what from an American point of view would be called treble cancelated trusses of the Linville type. The trusses are 19 feet 6¾ inches deep and 187 feet long over all, but their actual length from centre to centre of bearings is 183 feet 3 inches. The major portion of the body of iron intended to take the strains in the top and bottom booms is placed vertically instead as in many cases horizontally, an arrangement which tends to ensure greater uniformity in the distribution of the strains over the points of connection, at the same time giving considerable lateral rigidity.
'The superstructure throughout is rivetted, and as much as possible of the riveting was performed by the manufacturers, Messrs. Hopkins, Gilkes and Company in England, but, notwithstanding, 575,000 rivets had to be put in place in India in order to render the superstructure fit to support its rolling load. The rails, which are single-headed weighing 79 lbs. to the yard, are carried on heavy longitudinal timbers 10 inches by 16 inches, which rest on and are bolted to the wrought iron mow bearers. The total length of the bridge is 4687½ feet, the moving dimensions being 14 feet wide, 15 feet 11 inches high, which allows of the open wagons being utilised to the utmost with a load of half-pressed cotton. The weight of wrought iron in a single truss exclusive of rails and bearings is 186 tons. The total weight of wrought and cast iron in the bridge is as under:—Cwt iron in twenty-six piers, 6,327 tons ; cast iron in Rocker and Roller bearings, 215 tons; wrought iron in twenty-five spans, 4,554½ tons; wrought iron in 14 feet, bottom lengths, 612 tons; wrought iron main bearing girders and cross-struts, 1,525 tons : making a total of cast iron, 6,542 tons ; and wrought iron, 6,691½ tons. The construction of the new Nerbudda bridge was commenced on the 7th December, 1877, under the management of Messrs. J. White and G. H. Bayly, of the firm of Messrs. J. White and Company, to whom the contract for the Indian portion of the work had previously been let, the work throughout its whole course being further supervised by the Company's officers. The bridge was opened for traffic to-day, which gives a period of nearly three years-and-a-half for completing the structure.
'Throughout the whole of the above time the work was steadily pushed towards completion with hardly any interval of rest, as many as 28 columns being under process of sinking at the same time. In order to form some idea of the amount of labour necessary to sink these columns, I may mention that as much as 41,364 tons of top weighting had to be placed on the columns at an average height of twenty feet above low-water, and subsequently removed. In addition to the above weighting there was the combined weight of the columns with their internal rings of cement concrete, which amounted to 19,949 tons, giving a total weight of 61,313 tons, in order to attain 3,866 feet of sinking, which was considered necessary to ensure the stability of the piers. After the columns were sunk to the full depth and filled with cement concrete, a further test weight of 400 tons was placed on the top of each column, this weight was lifted through an average height of 411 feet, the columns sunk as an average under this weight only .076 of a foot. The total amount of Portland cement used in the concreting of the columns was 5,600 tons. This cement was specially prepared and tested in England, and again tested in India, the actual quantity of concrete in the bridge equals 22,434 yards. The depth of the foundation of the columns under the bed of the river varies from 55 to 104 feet and 74 to 1051 feet under low water. Some of these columns are supposed to have reached the greatest depths yet attained in bridge building, namely 101 feet under the bed of the river, or 105½ feet under low water, and in no case are any of these columns founded less than from 40 to 45 feet in hard material. The usual number of working days taken to complete the ordinary column was 200. Some of the deep columns, however, took 750 days. The boring through the conglomerates and tabular kunker which formed a large portion of the sinking, and in many cases 30 feet in thickness, was performed at the rate of 3½ inches per day. The tools used for boring and excavating the material, through which the columns penetrated, were devised and made by the contractors on the site of the work. They consisted chiefly of a boring head furnished with teeth like a rake, and an enlarger with a pair of steel cutting blades, capable of expanding from 7 to 14 feet in diameter. The former instrument bored a primary hole of 7 feet in diameter, the latter enlarged it by several cuts to 14 feet diameter. Where the conglomerate layers were too thick and offered unusual resistance to the boring head, heavy iron jumpers were used to break through the layers. The debris from the above operations was removed by Bull's dredgers, and, when necessary, by divers, who frequently worked under a head of 105 feet of water for short periods. Pumping had frequently to be resorted to during the progress of the sinking of the columns. For this purpose the pulsometer pump was found most efficient ; a No. 8 pulsometer frequently lifted water from a depth of 120 feet, in fact a better class of pump for the purpose could not be devised.
'The superstructure was erected for the most part on timber stagings, some of which were driven in 23 feet of water under low-water mark, the average time taken to place the material on the staging and rivet up a truss was 50 days ; some of the trusses towards the end were, however, completed in 35 days. The height of the underside of the truss over low water is 51 feet. The height of tide over high flood was 13 feet, the rise of tide at site of bridge during springs is 13 feet above low-water. The bridge was tested by the Government Engineer under a rolling load of 1.25 tons per foot run of truss, when it was found that the deflection at centre with a speed of 20 miles per hour was 0.08 of a foot or 0.96 of an inch, and the lateral oscillation 0.2 of an inch, which was considered very satisfactory.
'The cost of the New Nerbudda bridge is estimated as falling within 38 lakhs, or R810 per foot run of bridge. This cost will place it as one of the cheapest bridges in India, as well as, it must be admitted, one of the most rapidly constructed. The loss of life during its construction has been exceedingly small, when the magnitude of the work is taken into consideration., five lives only being lost on the work. The average number of men per month during the working seasons to whom employment has been given is as follows :—Men 36,936 ; women 5,663 ; boys and girls 1,237: total 43,836, or 1.427 per day. The above full and interesting description of the new bridge which, as I have previously stated, was procured an authentic source, will serve to give the reader an excellent idea of the great work which has been so excellently completed ; but no written description will convey an accurate idea of the gigantic and symmetrical proportions of the structure as viewed from either bank of the river. The substantial columns deeply imbedded in the stream give an impression of security to the spectator and of confidence to the traveller over the bridge ; whilst the comparison of the new bridge with the old is very unfavourable to the latter. ....' [Continues at length]
Silver Jubilee Bridge, 1935
The 1881 bridge carried only a single line, and the girders were too weak for increased loads and speeds. Construction of a new bridge started in 1932 and was completed in 1935. in 1935 at a cost of Rs. 76 lakhs and opened to traffic on 20 Dec 1935 [10].
The bridge was constructed by Braithwaite & Co. (India) Ltd, in association with The Hindustan Construction Company Ltd who built the piers. Construction work began in 1932. The bridge was completed in 1935 and inaugurated on 20 December 1935. This bridge is 1.406 km long, with 17 spans, 15 of which are 87.48 m long.
The above information is condensed from the Wikipedia entry.
The 1881 bridge remains in use for road traffic.