The new East River Bridge, planned to connect the foot of Broadway in Brooklyn with the foot of Grand street in New York, is being constructed under the authority of chapter 789 of the laws of 1895. The actual work of construction was begun on November 7, 1896, and it is now the expectation of the bridge commissioners and the engineer-in-charge that the bridge, completed, can be opened for traffic on January 1, 1901.

The act authorizing the construction of the bridge called for the appointment of six commissioners, three by the mayor of each of the cities, the mayors themselves being members of the commission ex-officio. The commissioners appointed by Mayor Schieren were Andrew D. Baird, James A. Sperry and Henry Batterman. The commissioners appointed by Mayor Strong were Salem R. Wales, Francis B. Thurber and Richard Deeves. The commission organized on June 26, 1895, and elected Andrew D. Baird President; Salem H. Wales vice-president; Francis B. Thurber secretary, and Rich and Deeves treasurer. Soon after organization the commission appointed Leffert L. Buck chief engineer and Othniel F. Nichols principal assistant. R.C.M. Ingraham and ex-Judge William G. Choate were named as the counsel to the commission.

A company called the East River Bridge Company had already been organized to build a bridge between the points named for the new structure. This company dated from 1892 and Frederick Uhlmann was its president. The first work of the commission was to get this older company out of the way, and on December 18, 1895, the new company purchased all the rights of the East River Bridge Company, paying for them $200,000. This conclusion of the matter was not reached by the commission without much opposition from the older company. The first offer made by the East River Company, through Mr. Uhlmann, was $200,000, provided the cars of the Brooklyn Elevated were allowed to cross the bridge; otherwise the company demanded $600,000. These two offers the commission rejected. They then decided that as they had the right to secure by condemnation proceedings the charter and rights of the company, they would avail themselves of their rights. They did so, with the result already stated.

The exact terminals of the bridge, as determined upon by the commission, are, in Brooklyn, a point just west at Roebling street, between South Fifth and South Sixth streets, and at Clinton street in New York. The northerly line at the bridge in New York corresponds with the southerly line at Delancey street.

Some of the Obstacles Overcome

The difficulties in the way of the new bridge were many, although the science of bridge building has advanced rapidly within the past few years. Fully realizing the present overcrowding of the present bridge, thought when it was intended to be fully equal to any demands that could be made upon it for years to come, the commission planned its bridge to provide for the traffic of years to come. In the first place it was decided that it was to be a railroad bridge. This point settled, the commission, in order to provide plenty of room for all classes of traffic, provided that the bridge should be 118 feet wide, nearly 50 per cent. wider than the present bridge; should have two foot ways, each nearly as wide as the foot way on the present bridge; two roadways, two tracks for the elevated roads, and four tracks for the surface cars. With such a bridge in operation, the commission feel that they will have provided a bridge that will serve for years to come, and in the opinion of engineering experts their opinion is well founded.

The bridge will have two towers, each rising 340 feet above the water. The foundation on which the New York tower will rest will be about 60 feet below high water. The depth under the Brooklyn foundation will be about 90 feet below high water. Each tower will rest on solid blocks of masonry, these blocks in turn resting on the bed rock of the river. it may be noted here that these foundations, almost, if not quite the most important features of the bridge, are not so large as the foundations for the towers of the old bridge, although the new bridge is larger and heavier than the old one. The reason for this is that the new towers are to be constructed of steel instead of masonry, and will consequently be lighter than the old towers. In the old bridge the towers weigh ten times as much as the bridge itself. The new towers will be lighter, and will be built in much less time than was required for the old ones.

Building the Foundations

The most important work being done at present is on the foundations for the towers. The process by which the foundations are being sunk to bed rock is called the pneumatic process. It was first used in this country in 1859 in the erection by Mr. C.C. Martin and General W.F.S. Smith on a bridge over the Savannah River, in Georgia. Since that time the process has come to be used in all foundation work, where the depth does not exceed 120 feet. It is considered to be the only economical process by which a complete examination and preparation of the base of the foundation can be made where the depth exceeds thirty to forty feet. In brief, the process is as follows:

Caissons are so built that they resemble very much a flat boat upside down. The side walls, about eight feet high, with a cutting edge at the bottom, form an internal chamber, called the working chamber. Over this chamber is laid a roof of convenient thickness. The appearance of the Caisson when completed is that of an immense box cover. When completed the caisson is launched and towed to its position at the site of the proposed foundation. The masonry can then be started on the deck of the caisson. As soon as the caisson has been sunk to the bed of the river, so that the side walls rest on the bottom, compressed air may be pumped into it. When the pressure is sufficient to keep the water out men may be sent into the working chamber through air locks, which are opened to the outer air, then closed to that and when the pressure is equalized with that of the chamber opened to it. Thus the men find themselves in a chamber about 8 feet high, lighted with electricity and fitted with telephones, all ready for sinking. As fast as the material is excavated it is passed to the outer air and is removed. This excavation goes on rapidly and the caisson, under its weight of masonry, settles easily to its position. When it has reached its final position the working chamber is completely filled with concrete, so that when the pressure of air is removed the masonry will be continuous from its top to bed rock, excepting for the timber of the deck of the caisson, which forms a layer between the upper and lower masses of stone work. One caisson on the New York side is fully sunk and now being filled with concrete; the other caisson is being sunk, while the fourth and last caisson for the Brooklyn side is now being prepared for launching.

Work has been begun on the anchorages, and the visible signs of the new bridge on this side of the river are now present. The employees of the contractors have torn down the buildings which stand on the site of both of the anchorages and excavations are in progress and well under way. During January the commission will let the contracts for the steel towers and shore spans, which connect the towers with the anchorages. In construction these shore spans will differ materially from the shore spans of the present bridge. They will not be suspended from the cables, as in the old bridge, but will be supported by the towers and anchorages, and by an intermediate pier, located in Brooklyn, just west of Kent avenue, and in New York west of East street. Engineer Buck expects that this portion of the steel work will be completed early in 1899, and the manufacture of the cables can then begin. The contracts for the steel towers and shore spans will approximate 10,000 tons. Of the anchorages it may be said in passing that their foundations need not go to the rock and that they will contain a great deal of steel in the shape of anchor plates and fittings, to which the bars receiving the cables will be attached. As has been said, by the time the anchorages are completed the towers will be up and cable making can begin. By reason of the many improvements in cable construction it is expected that this part of the work can be done in much less time than was required for the old bridge.

The commissioners have already acquired the land for the shore towers in Brooklyn, and in New York. No more real estate will be taken until late in 1898, when it will be necessary to begin on the approaches.

In the construction of each anchorage the first thing to be done will be to drive a line of piles twelve inches square, close together all around, forming a wooden inclosure. In Brooklyn the excavation for the anchorage will be 45 feet deep, in New York 25 feet deep, but 20 feet below high water. The foundation on the New York side will rest on about 3,000 piles. On the Brooklyn side the foundation will be 15 feet below high water, because the sand bottom found will not require so much piling. In all probably 1,500,000 feet of yellow pine timber will be required. It has not yet been decided where the granite for the anchorages will come from, but the limestone will be taken from a quarry opened expressly for the purpose at Howe's Cave, on the Delaware and Hudson Railroad, forty miles below Albany. In each anchorage will be used 10,000 cubic yards of concrete, 45,000 cubic yards of masonry and 1,600 tons of steel.

Progress of the Work Generally

Chief Engineer Buck has reported that the filling in at the New York caisson with masonry has begun. it is expected that these foundations will be finished in July and the Brooklyn one in the fall. The immense towers, which will stand on the completed caissons, will be of steel, consisting of four corner posts, connected with transverse lattice bracing. The tops will be 335 feet above high water, and the bridge will be supported by four 18 inch steel wire cables. The clear height under the bridge will be 117 feet at the pier head lines and not less than 135 feet, for 400 feet in the center, above the mean high water of spring tides, in the summer, when the cables are the lowest and when the bridge is fully loaded. This means that for the greater portion of the time the bridge will have upward of 140 feet at clearance over the water for at least 400 feet near the center.

The fourth and last caisson to be used in the construction of the bridge was launched on Wednesday, December 15. This caisson will be part of the foundation of the Brooklyn tower, the other caisson for this foundation having been launched some time ago. The work of sinking the last caisson to the bottom of the river began immediately after it had been lowered to its position, and it is now well under water. The launch was witnessed by a large number of persons, among them being Mayor Wurster, Commissioners Batterman, Wales and Deeves, Bridge President Berri, Chief Engineer Buck and Assistant Engineer Nichols.