Forth Bridge

"Operations were commenced in January, 1883, so the works have now been some twenty months in progress, and about 170,000£. have been expended in plant and temporary works and 200,000£. in the permanent works of the bridge. At an area of about 20 s of ground have been laid out in shops and yards for the manufacture of the 1700 span steel girders and for other purposes. These shops are in direct communication with the North British Railway, and are connected by an incline and with a temporary timber viaduct 2200 ft. in length and 50 ft. in width, extending from the South Queensferry shore to the first of the groups of four cylindrical iron caissons which constitute the lower portions of the main piers of the bridge. At stores and offices have been built, and as this in an exposed island in the middle of the Forth the staging for the piecework is of iron pinned to the rock. Similarly at , on the Fife side of the Forth, stores, offices, and iron staging have been erected."

"The for many years have striven hard to obtain a physical connection of their lines north and south of the Forth by means of a bridge. Twenty years ago they were authorized by to build a bridge across the Forth at a point five miles above the site now under construction., but borings 120 feet in depth showed nothing but soft silt and mud, and the bridge, which was to have been two miles in length, inclusive of the four spans of 500 feet each, was luckily abandoned, as the difficulties with the foundation would have proved practically insuperable. In 1873 another Act was passed for a bridge across a narrower and deeper part of the Forth at . At low water the width of the channel there is about 4,000 feet; and the island of affording a foundation for a central pier, it was possible to cross the 200 feet deep portion of the sea-way by a couple of spans from 1,600 feet to 1,700 feet each in the clear."

"The Forth Bridge is one of the world's most recognizable s and a milestone in engineering history. It opened in 1890 and is still going strong 125 years later."

"The bridge across the Firth of Forth was completely redesigned, as a , by the engineers and . Its unusual form was a deliberate attempt not only to make the bridge stronger than but also to make it look like it could withstand the wind and just about anything else that nature or man could throw at it. ... Although the cantilever form was not totally new with the Forth Bridge, which was completed in 1890, it quickly became very fashionable. For the next decade or so, a cantilever design option was often presented as a challenge to any proposed design."

"The most interesting and novel features in connection with the earlier stages of the work was probably the construction of and piers by the . ... Each pier has at its base a diameter of 70 feet, and is built with a sufficient to reduce it to 49 at the level of the . From low water each pier is faced with granite averaging 2 feet in thickness. Below this point is a solid mass of concrete covering the 70 feet area already mentioned. The interior of these piers is composed of Arbroath stone set in cement. At the level of coping a course of granite forms the surface of each pier, through which project 48 steel bolts 2½ inches in diameter, extending downwards to a depth of 24 feet, where they are secured by washer plates designed for the purpose."