Days. Year. Days. Year. Days. Year. Days. Year. Days. Year. Days. Year. Days. Year. Days. Year. High water of 1832. No losses have ever been reported as caused by this bridge, and we have no changes to recommend. The original cost of the bridge, without including real estate or anything not directly chargeable to the construction account, was $1,480,000. LOUISVILLE BRIDGE. This bridge, sometimes known as the Ohio Falls bridge, is a railroad and foot bridge, and it crosses the Ohio at the head of the falls, extending from a point just below the city of Jeffersonville, in Indiana, to the foot of Fourteenth street, in the city of Louisville. It belongs to a special bridge corporation, and serves to connect the Indiana railway system with the roads on the south of the Ohio that center at Louisville. The bridge company was chartered by the State of Kentucky, with authority to construct a bridge that should not obstruct the navigation of the Ohio, "further than the laws of the United States and the decisions of the Supreme Court shall hold to be legal." Their authority from the United States is derived from the act of Congress approved February 17, 1865, which is supplementary to the act of July 14, 1862, under which the Steubenville, Bellaire, and Parkersburgh bridges are built. Under these acts the company were authorized to build any one of the three following styles of bridge, viz: 1. Continuous 90 feet above low water. 2. With a draw 70 feet above low water. 3. With three draws 56 feet above low water. The location of this bridge is peculiar, and the provisions of the act of 1862 do not apply very well. The authority to build under that act might have caused a great deal of injury to navigation, had its provisions been interpreted to the letter. At the Falls of the Ohio there are really three navigable channels to be crossed-the Indiana Chute, the Middle Chute, and the canal. As the act in question only contemplated one channel, an illiberal interpretation might have resulted in seriously affecting navigation through the others. Fortunately the company met the difficulties of the case in a most commendable public spirit, and they not only adopted the highest of the three bridges, but they largely increased the channel-ways that they were required to give. This bridge, as built, belongs to the class of "high" bridges, as distinguished from bridges with draws, and an elevation of but 70 feet. It has a single railroad track, and two sidewalks, each 7.2 feet wide, and its total length between abutments is 5,218 feet. The spans commencing at the abutment on the Indiana or north shore are as follows: 99, 149.6, 180, 180, 180, 3983, (Indiana Chute,) 245, 245, 2451, 2451, 2454, 245, 370, (Middle Chute,) 227, 227, 210, 210, 180, 180, 149.58, 149.58, 149.58, 149.58, 132, 132, (draw over canal,) 50, 50. These dimensions are from center to center of piers, and they are greater by the half widths of two piers than the clear water-way. The trusses themselves are of the two styles patented by Mr. Albert Fink, the chief engineer of the bridge. The two channel-spaces are spanned by Fink triangular trusses, and all the others except the draw by Fink trussed girders. The draw-bridge is what is generally known as a Warren girder, differing only from the triangular, in that the latter has certain additional members that are necessary to adapt it to long spans. The former are "through" or "over-grade" bridges, and the latter "deck" or "undergrade." The clear waterway at the Indiana Chute, measured on the lowwater line, is 380 feet, and at the Middle Chute 3524 feet. The roadway bearers of the channel-spans are suspended below the bottom chords, and consequently the height under the bridge available for steamboats must be measured to these members. The line of the roadway bearers of the Indiana channel-span is 963 feet above low water, and 453 feet above highest water, the maximum oscillation being 51 feet. At the middle channel-space the river is dry at low water, and the available space above the river-bed is 90 feet. These two channel-spans are on the same level, but at the Indiana channel the break in the rocky ledge is 1,000 feet above, while at the middle channel it is 6,000 feet below. The line of the crest of the falls is exceedingly irregular, crossing the lineof the bridge between the the two channel-spans nearly at right angles. The tops of the four channel-piers and of all piers between them are 974 above low water of the Indiana Chute. The others are lower, conforming to the grades of the bridge. The foundations of all the piers of this bridge were laid on the solid rock, and therefore there is no need of any riprap protection around them. Current observations were made by the surveying party, but they were of little practical value. The water was too low to permit boats to cross the falls, and therefore it was of no importance to ascertain the angles between the current at this stage and the piers. As the river rises, the effect of the falls becomes gradually less perceptible, and the currents become more and more regular, until in high water the falls entirely disappear. We have good reasons for believing that the bridge is as nearly as possible at right angles to the current at navigable stages, and therefore did not think it worth while to incur the expense of a special survey at high water. The right pier of the Indiana channel-space is 64 feet 6 inches by 17 feet 10 inches at bottom; thence it is carried up vertically with 10 inches of offsets, to 10 feet above low water. Above this the sides have the uniform batter up to the coping of of an inch per foot. The left pier is 65 feet 6 inches by 18 feet 8 inches at bottom, and is carried up vertically with 1 foot 64 inches of offsets to 18 feet above low water. Above this the sides have the usual batter. The up and the down stream ends of the piers are built alike, with starlings formed by the intersection of arcs of circles with radii of 123 feet. They are capped by hoods at high water mark, and above this are finished with semicircular sections. These piers, on top, (without coping,) measure 33 by 10. The piers of the middle channel are 64 by 173 feet at bottom, and 33 by 10 feet on top, with starlings and hoods like the other channel-piers. The other piers are similarly constructed, excepting that above the lower starlings and hoods they have another starling and hood, which makes a shorter length of pier on top. The top dimensions of pier No. 7 (without coping) are 21 by 7, the dimensions at bottom being 453 by 141. The grades and curvatures on this bridge and its approaches are as follows, commencing at the face of the abutment on the Indiana or northern shore: The approach to this bridge on the Indiana shore consists of a long and high embankment. This, however, does not properly belong to the bridge, and in accordance with the rule adopted for other bridges we consider that we have reached the end of a bridge when we come to earth-work Under this rule this bridge has no approaches, the entire space from abutment to abutment being water-way. This bridge crosses the Louisville and Portland Canal 1,700 feet below the guard-lock at the head. An unobstructed passage-way for steamboats is secured by means of a draw, giving a clear opening of 114 feet over the canal. The other end of the draw projects over a portion of the river, and by modifying the canal-bank on this side so that it shall just have the width of the pivot of the draw it will be practicable for steamboats in high water to ascend the river without lowering their chimneys. This is a very valuable provision for boats that habitually run where there are no bridges, which yet may occasionally wish to go above Louisville. In low water such boats can pass through the canal, and in high water, by using the other end of the same draw, they can pass up the river even should they be too wide to get through the new locks. The changes in the canal bank necessary to permit this use of the northern end of the draw are being made by the United States as a necessary adjunct to the enlargement of the canal. The total high-water section of the river on the line of the bridge is 216,249 square feet, of which 13,573 square feet, or 6 per cent., is occupied by the piers. This contraction would probably cause no perceptible increase of volocity. The low-water section is 1,377 square feet, of which 60 square feet, or 44 per cent., is obstructed. All the water at this stage is running through the Indiana Chute, but there being no navigation possible the effect of the piers need not be considered. The losses by collision with the piers of this bridge up to date amount to $26,704. (Appendix B.) The board have no changes to recommend in this bridge, which they consider a first-class structure throughout, and very much less an obstruction than it might have been had its builders limited themselves to giving only what they were compelled by law to give. On the contrary they have chosen to build according to the highest of the three authorized plans, and have exceeded the heights and widths that even this plan required, spending $150,000 more than was necessary to comply with the letter of the law. Instead of a 300-foot opening at low water, one of their channel-spans gives 380 feet, and the other 3524 feet. The total cost of the bridge, from abutment to abutment, was $1,615,120. If it should be found by experience that owing to the peculiar location of this bridge the channel space on the Indiana side cannot be safely run by coal-tows, then a still wider opening will be necessary. Present difficulties, however, may possibly be due to a lack of experience; should it be found, however, that there are inevitable dangers due to this exceptional location which no amount of experience can avoid, it will be manifestly necessary to widen this span to 500 feet, or in some manner to modify existing conditions so as to facilitate the passage of the present opening. The record of the average and the extreme stages of the river for the years 1851, 1858, 1859, 1866, 1867, 1868, 1869, and 1870, is given in the following tables for the head and the foot of the falls. No other records of the stage of water on the falls could be obtained. As the main channel opening of the bridge is located below the head and above the foot of the falls, the exact space under the bridge cannot be obtained from these tables, and has therefore been omitted. At the head of the falls |