FORTH BRIDGE Reprinted from "ENGINEERING," February 28, 1890. GITY OF CALIFORNIA EiERKELEY. CALIFORNIA UNIVERSITY OF CALIFORNIA i, CALIFOftMA f / THE FORTH BRIDGE. Reprinted from "ENGINEERING," February 28, 1890. THIBD EDITION, BEVISED, WITH APPENDIX. LONDON : OFFICES OF "ENGINEERING," 35 & 36, BEDFORD STREET, STRAND, W.C. /="7l CONTENTS. PAGE HISTORICAL 1 RAISING OP THE APPROACH VIADUCT GIRDERS, AND UNDERBUILDING ON CANTILEVER BRIDGES GENERALLY OF THE PIERS 5 .. 32 THE STEEL SITE OF BRIDGE AND PROFILE ON CENTRE LINE. SURROUNDING 35 COUNTRY 7 DRAWINGS 37 TIDES, WIND, WIND PRESSURES, AND GAUGES. CLIMATE GENERALLY 7 WORKSHOPS 37 WIND PRESSURE AND WIND GAUGES 9 BEDPLATES 39 EXPERIMENTS ON WIND STRESSES ... ... 10 THE MEMBERS FORMING THE CANTILEVERS 47 GENERAL DESCRIPTION OF THE STRUCTURE 10 BUILDING OUT OF THE CANTILEVERS 50 COMMENCEMENT OF WORK 12 RIVETTING 59 TRANSPORT AND DISTRIBUTION OF MATERIAL ... ... ... ... 14 TEMPORARY WORK IN CONNECTION WITH THE ERECTION 59 LIGHTING 14 THE USE OF WIRE ROPE 60 MATERIALS OF CONSTRUCTION FOR THE MASONRY PIERS 15 THE PERMANENT WAY 61 WATER 16 EXPANSION JOINTS IN RAILS 61 CEMENT ... 17 PAINTING 61 COMMENCEMENT OF THE PERMANENT WORK 17 ASPHALTING 61 GENERALLY ABOUT COFFERDAMS 17 THE WORKMEN 61 INCHGARVIE NORTH CIRCULAR PIERS 18 THE RAILWAY CONNECTIONS 62 FIFE SOUTH CIRCULAR PIERS 18 THE SOUTH APPROACH RAILWAY 63 SOUTH APPROACH VIADUCT PIERS 19 THE NORTH APPROACH RAILWAY 63 PRELIMINARY WORK IN CONNECTION WITH THE INCHGARVIE SOUTH WEIGHT OF THE SUPERSTRUCTURE 63 PIERS 19 THE FORTH BRIDGE RAILWAY COMPANY 63 PRELIMINARY WORK IN CONNECTION WITH THE FOUR QUEENSFERRY THE VISITORS ... CAISSONS 21 64 THE PRELIMINARY TESTS BUILDING OF THE CAISSONS 23 64 ENGINEERS THE AND CONTRACTORS OF THE FORTH BRIDGE : AIR COMPRESSORS 23 SIR JOHN FOWLER, K.C.M.G 64 ACCIDENT TO No. 4, OR QUEENSFERRY SOUTH-WEST CAISSON ... 26 MR. BENJAMIN BAKER 69 SINKING OF THE CAISSONS 27 SIR THOMAS TANCRED 69 QUEENSFERRY CAISSONS 29 MR. WILLIAM ARROL 69 INCHGARVIE CAISSONS 30 MR. T. H. FALKINER 70 THE CIRCULAR GRANITE PIERS 31 MR. JOSEPH PHILLIPS 70 MONS. L. COISEAU 71 APPENDIX. INSPECTION AND TESTING OF THE FORTH BRIDGE BY THE BOARD OF TRADE. 71 LIST OF PLATES. PLATE TO FULL HEIGHT. FIFE PIEU, FROM THE NORTH-WEST. I. PORTRAIT OF SIR JOHN FOWLER, K.C.M.G. PLATFORMS RAISED TO FULL HEIGHT. II. PORTRAIT OF MR. BENJAMIN BAKER. XII. FIFE CANTILEVER. SIDE ELEVATION LOOKING EAST. III. THE FORTH BRIDGE. XIII. EFFECT OF SEA FOG. CENTRAL TOWERS AND SOUTH APPROACH IV. GENERAL VIEW OF BRIDGE SOUTH CENTRAL GIRDER CONNECTED ; ; VIADUCT. H.M.S. "DEVASTATION" PASSING FIFE PIER. NORTH CENTRAL GIRDER NOT COMPLETED. GENERAL VIEW OF CENTRAL TOWERS AND APPROACH VIADUCTS, V. GENERAL VIEW OF SITE LOOKING NORTH-EAST. CAISSON BUILDING LOOKING NORTH. QUEENSFERRY NORTH-EAST PIER. PUTTING ON LAUNCHING WAYS. TOGETHER UPPER BEDPLATE. VI. VIEW FROM INCHGARVIE CASTLE. THE SOUTH CAISSON IN POSITION. XIV. INCHGARVIE PIER. RIVETTING IN TOP MEMBERS BETWEEN VERTICAL COLUMNS. PIER. INTERSECTION OF DIAGONAL VII. LAUNCHING OF CAISSON FOR SOUTH-WEST PIER, INCHGARVIE. QUEENSFERRY WITH AND DIAGONAL BRACING GIRDERS. GENERAL VIEW OF SITE, WITH PIERS OF SOUTH APPROACH STRUTS HORIZONTAL VIADUCT, LOOKING NORTH. BUILDING OF NORTH-EAST CIRCULAR XV. FIFE PIER. FIRST HALF-BAY IN FIXED CANTILEVER, SHOWING GRANITE PIER, INCHGARVIE. CAISSON FOR QUEENSFERRY LIFTING PLATFORM FOR BUILDING THE LOWER PORTION OF NORTH-WEST PIER. CONSTRUCTING TIMBER CASING ROUND BAY, AND TOP MEMBER CRANE WITH PLATFORM SUSPENDED THE TILTED CAISSON. FROM rr. MAKING GOOD A CROSSING BETWEEN STRUTS AND VIII. FRONT VIEW OF NORTH CANTILEVER END PIER, AND VIEW OF TIES IN FIRST BAY OF CANTILEVER. VIADUCT AND ARCHES. NORTH APPROACH RAISING PIER HORIZONTAL AND DIAGONAL VIADUCT ; XVI. CENTRAL TOWER, QUEENSFERRY ; VIADUCT GIRDERS. NORTH APPROACH PART OF INTERNAL VIADUCT AND TEM- VIADUCT ; GIRDERS BRACING GIRDERS ; RAISED TO FULL HEIGHT. PORARY STAGING. QUEENSFERRY PIER. INTERNAL VIADUCT FROM CENTRE OF BAY TO WITHIN CENTRAL TOWERS. IX. FIFE PIER. ERECTION OF SUPERSTRUCTURE ; CONSTRUCTION OF LIFTING PLATFORMS. INCHGARVIE PIER. ERECTION OF SUPER- XVII. FIFE PIER. LOWER HALF OF FIRST BAY IN FIXED CANTILEVER. LOWER HALF OF FIRST STRUCTURE ; RIVETTINO CAGES AND HYDRAULIC RIVETTING FIFE PIER. CENTRAL TOWER AND MACHINES ON VERTICAL COLUMN AND DIAGONAL STRUT. BAY IN FREE CANTILEVER. FIFE PIER. ERECTION OF SUPERSTRUCTURE LIFTING PLAT- ; XVIII. FIFE PIER. FREE CANTILEVER COMPLETED AND CENTRAL GIRDER FORMS ABOUT 100 FT. ABOVE HlGH WATER. CAGE FOK COMPLETED. COMMENCED ; FIXED CANTILEVER NOT QUITE RlVETTINU AND BUILDING BOTTOM MEMBERS. XIX. QUEENSFERRY PIER AND INCHGARVIE SOUTH CANTILEVER, WITH X. QUEENSFERRY PIER, LOOKING NORTH. LIFTING PLATFORMS ABOUT PARTS OF CENTRAL GIRDER BUILT OUT. INCHGARVIB SOUTH 190 FT. ABOVE HIGH-WATER LEVEL. CANTILEVER, WITH FIRST BAY OF CENTRAL GIRDER BUILT LOOKING INTERNAL VIADUCT XI. QUEENSFERRY PIER, NORTH. PLATFORMS RAISED TO FULL OUT. CENTRAL TOWER ON INCHGARVIE ; HEIGHT. FIFE PIER, LOOKING SOUTH. PLATFORMS RAISED GIRDERS AND WIND FENCE. 403025 LIST OF ILLUSTRATIONS. PAGE MAP SHOWING THE FORTH BRIDGE AND RAILWAY CONNECTIONS ... 2 FIG. 1. ANDERSON'S DESIGN FOR BRIDGE OVER THE FORTH, 1818 FIGS. 2 AND 3. ALTERNATIVE PRELIMINARY DESIGNS FOR THE FORTH BRIDGE FIGS. 4 AND 5. THE FORTH BRIDGE, CANTILEVER TYPE ; ORIGINAL AND FINAL DESIGNS FIGS. 6 TO 15. TYPES OF CANTILEVER BRIDGES FIG. 15A. LIVING MODEL, ILLUSTRATING PRINCIPLE OF THE FORTH BRIDGE FIG. 16. MAP OF THE FIRTH OF FORTH FIGS. 17 AND 18. WIND GAUGES ON INCHGARVIE FIG. 19. EXPANSION DIAGRAM OF FORTH BRIDGE FIG. 20. TEMPORARY STAGING ON INCHGARVIE FIGS. 21 AND 22. BEARING OF CAISSONS ON ROCK FOUNDATION... FIGS. 23 TO 28. DETAILS OF SOUTH APPROACH PIERS FIGS. 29 AND 30. INCHGARVIE SOUTH-WEST CAISSON FIG. 31. RAFT USED FOR SURVEY OF FOUNDATION FIG. 32. CUTTING EDGE OF CAISSON FIGS. 33 TO 35. PNEUMATIC CAISSONS, QUEENSFERRY ... 20 FIG. 36. SECTION OF CAISSONS AT INCHGARVIE FIG. 37. CAISSON AND CRADLE IN LAUNCHING WAY FIGS. 38 AND 39. AIR LOCKS FIG. 40. Am LOCKS ON CAISSONS FOR ADMITTING AND REMOVING MATERIALS ... ... FIGS. 41 TO 45.. AIR LOCK AND HOISTING GEAR ON CAISSONS ... FIG. 46. TILTED CAISSON AT SOUTH QUEENSFERRY FIG. 47. SECTION OF TILTED CAISSON AFTER COMPLETION FIG. 48. SINKING THE QUEENSFERRY CAISSONS FIGS. 49 AND 50. HYDRAULIC SPADE FIG. 51. SECTION OF CAISSONS WITH AIR LOCKS AND WORKING CHAMBERS FLOATING OUT CAISSON FOR QUEENSFERRY PIER, MARCH 26, 1884 FIG. 52. STRUTS AND WEDGES IN AIR CHAMBER FIG. 53. PIER WITH PERMANENT CAISSON FIGS. 54 TO 59. MODE OF FIXING UNDER BEDPLATES ON PIERS FIGS. 60 AND 61. HEATING FURNACE FOR PLATES FIGS. 62 AND 63. HYDRAULIC BENDING PRESS FOR PLATES FIGS. 64 AND 65. MACHINE FOR PLANING ENDS OF CURVED PLATES FIG. 66. MACHINE FOR PLANING EDGES OF CURVED PLATES FIG. 67. PLAN OF DRILL ROADS FIGS. 68 TO 71. BOTTOM MEMBER ON DRILL ROAD FIGS. 72 AND 73. TUBE DRILLING MACHINE ON DRILL ROAD THE FORTH BRIDGE. BY W. WESTHOFEN. HISTORICAL. explanation of the many struggles and attempts beaten down the Firth, and had finally to land on IT has at all times been a subject for contro- made by the East Coast lines to obtain a separate the island of Inchcolm, five miles away. He founded versy and a matter of difficulty to fix the precise access to the counties north of the Forth. How a priory on that island as a thanksoffering to boundary line between the river and the sea, that great the necessity was of having means of com- Providence for a very narrow escape and in view is to say exactly where the sea ends and the munication between the two shores, and how largely of a warmer reception and more substantial enter- river commences. With regard to the Forth and even the inadequate provisions made hitherto were tainment should a similar misfortune again befall its estuary, the same discussion has been carried taken advantage of, is proved by the fact that in him. So must also many of the poor wayfarers who on in Parliament and elsewhere with considerable 1805 before a steamboat existed or a railroad was got drenched to the skin and suffered the horrors warmth, but does not appear at the present moment thought of the right of running ferryboats between of sea-sickness during the crossing, and so must to have got any nearer to settlement than in 1882. South and North Queensferry was let at a yearly finally if there was time for them to do so the a in Fife- rental of 2000?. and it is stated in the unfortunate of who were driven down Taking, however, point, say Anstruther, , Parliamentary party people shire, and another, say Dunbar, in Haddington- evidence then taken that the revenue derived by the Hawes Brae at so rapid a pace that horses, shire, and drawing a line across which, roughly outsiders who run goods and passengers across in carriage, and passengers went right off the pier speaking, passes near the May Island and the Bass yawls and small boats amounted to fully 5000Z. per into the water and none of them came out alive. Rock, we may call it the Forth within and the sea annum in addition. The idea thus floated through many minds until without this imaginary boundary line. Starting It must be admitted that the Forth Bridge crosses about 150 years ago, when a bridge was first spoken westward from it we have 32 miles to Queensferry the river at a point which leaves the eastern counties of, but particulars as to design, site, or probable and 30 miles further to Stirling. On both sides of still somewhat in the same difficulty, but it reduces cost do not seem obtainable. this great watershed are situated hundreds of square many of the local distances to be traversed In November, 1805, a proposal was made to con- miles of some of the most fertile and best cultivated by more than one-half, and the gain in time is con- struct a double tunnel 15 ft.