said that the Author had been Dfr. Harrison good enough to give an account of the substructure of the Tower Bridge. He trusted that when the bridge was finished the Author would also give an account of the superstructure. The bridge was original both in conception and in design and it was important that a complete account of it should appear in the Minutes of Proceedings. He had much satisfaction in proposing a vote of thanks to the Author for his useful and practical Paper. DISCUSSION ON THE

more »

... VZR-PIERS [Minutes of I\lr.Walmisley. 1 9 arches, had two-thirds of the water-way occupied by piers ; old Westminster bridge had one-third and Vauxhall bridge one-sixth of the water-way occupied by piers; and at the Tower Bridge there was between one-fifth and one-sixth. The width occurred in definite positions, while the mid-stream space and the space nearest the shore upon each side of the ri.;er was unobstructed, giving 200 feet of space in the centre, where it was most required -in deep water-for vessels to go by, should the span be frequently opened. He questioned very much whether it would be frequent,ly opened ; but provision was made, should i t be required. The unit loads allowed upon the foundations, as stated by the Author, appeared perfectly safe. In the Institution Library there was B printed copy of a pamphlet written by himself some years ago, in which he had described the foundations of some of the old bridges of the Tha1nes.l Sir Benjamin Sir BENJAMIN BAJCEP., Vice-President, considered it somewhat Baker. Bridges over thc Thames at London, 1880. Inst. C.E., Tracts Svo., vol. 369. Downloaded by [] on [12/09/16].