The Forth Bridge/Weight of the Superstructure
Weight of the Superstructure.
The subjoined tabular statement will give some idea of the amount of steel distributed over the main supports.
| Description of Parts. | Fife. | Inchgarvie. | Queensferry. | Total. | |||||||||
| Tons | Cwt. | Tons | Cwt. | Tons | Cwt. | Tons | Cwt. | ||||||
| 3 Central towers, including bedplates | … | 4815 | 16 | 7036 | 4815 | 16 | 16,667 | 12 | |||||
| 6 Cantilevers | … | … | … | … | 1 fixed 1 free | 2 free | 1 fixed 1 free | ||||||
| Bay 1 | … | … | … | … | … | 4235 | 4 | 4312 | 12 | 4235 | 4 | 12,783 | |
| " 2 | … | … | … | … | … | 2626 | 2 | 2658 | 12 | 2626 | 2 | 7910 | 16 |
| " 3 | … | … | … | … | … | 1764 | 6 | 1724 | 16 | 1764 | 6 | 5253 | 8 |
| " 4 | … | … | … | … | … | 1034 | 3 | 1009 | 16 | 1034 | 3 | 3078 | 2 |
| " 5 | … | … | … | … | … | 665 | 18 | 620 | 4 | 665 | 18 | 1952 | |
| " 6 | … | … | … | … | … | 490 | 2 | 423 | 12 | 490 | 2 | 1403 | 16 |
| 2 Central girders | … | … | … | … | 410 | 15 | 821 | 10 | 410 | 15 | 1643 | ||
| Rocking-posts and steel castings | … | … | 51 | 9 | 51 | 9 | 51 | 9 | 154 | 7 | |||
| Ladders in tubular members | … | … | 36 | 40 | 36 | 112 | |||||||
| Totals | … | … | 16,129 | 15 | 18,698 | 11 | 16,129 | 15 | 50,958 | 1 | |||
| Weight of a | fixed cantilever: 5441 tons. |
| "" | free cantilever: 5375 tons. |
| "" | 1710 ft. span: 11,571 tons 10 cwt. |
| "" | cantilever bridge per foot run: 9 tons 11 cwt. |
Table No. XII. on the next page shows the quantities of steel erected and bolted up and rivetted during the years 1887, 1888, and 1889, month by month. These quantities apply to the three main piers of the cantilever bridge only.
The total cost of the foundations of the Forth Bridge may be roughly put down as nearing 800,000l; and in connection with this expenditure it is necessary to mention the name of Mr. P. W. Meik, who acted as resident engineer for, and as representative of, Messrs. Sir John Fowler and Baker from the commencement in 1883 until the completion of the masonry piers in 1886, and of whose unfailing tact and courtesy his many friends retain the liveliest remembrance.
Another name should be added here, that of Mr. William Gray, who from start to finish had charge of all excavation and masonry work, besides other duties of the most multifarious character, and of whom it may be truly said that, day or night, early or late, no one would ever call upon him and find him unwilling to do what was wanted.
The total expenditure by the Forth Bridge Company upon construction has been as follows. The figures are approximate amounts as far as expenditure year by year is concerned, but the total amounts are correct and authentic.
| For half-year ending | ||
| These amounts include the expenditure for the construction of the north and south approach railways, but nothing for the connecting line. | ₤ | |
| December 31, 1882 | 7000 | |
| June 30, 1883 | 42,800 | |
| December 31, 1883 | 57,000 | |
| June 30, 1884 | 119,000 | |
| December 31, 1884 | 218,200 | |
| June 30, 1885 | 231,000 | |
| December 31, 1885 | 216,000 | |
| June 30, 1886 | 188,000 | |
| December 31, 1886 | 253,500 | |
| June 30, 1887 | 240,000 | |
| December 31, 1887 | 243,000 | |
| June 30, 1888 | 195,700 | |
| December 31, 1888 | 218,000 | |
| June 30, 1889 | 182,000 | |
| December 31, 1889 | 138,000 | |
| Total…… | 2,519,200 | |
| Add to this the amount expended in connection with Sir Thomas Bouch's suspension bridge (including all parliamentary expenses) | 250,000 | |
| 2,799,200 | ||
| Parliamentary expenses in connection with cantilever bridge, engineering expenses, interest during construction, &c. | 378,006 | |
| Total expenditure to January 1, 1890 | 3,177,206 | |
It is estimated that a further sum of 50,000l. will be required to complete the structure, the painting included.
The sale of plant is expected to realise fully 120,000l.
For the erection alone of the Fife, Inchgarvie, and Queensferry Piers, that is, everything on top of the circular granite piers which may be strictly called the superstructure, the amount of wages paid including salaries of officials in charge of the piers, amounted up to November 30, 1889, to a total sum of 344,810l; the total amount of steel put up and rivetted up to that date being 50,064 tons. The cost of labour for that work is therefore 62. 17s. 9d. per ton erected and rivetted up.
The total amount of wages and salaries paid on the works up to January 1, 1890, was 1,045,000l.