AMERICAN SOCIETY OF CIVIL ENGINEERS
INSTITUTED 1852
TRANSACTIONS
Paper No. 1176
REINFORCED CONCRETE PIER CONSTRUCTION.
By Eugene Klapp, M. Am. Soc. C.E.
With Discussion by Messrs. William Arthur Payne,and Eugene Klapp.
A private yacht pier, built near Glen Cove, Long Island, hasbrought out a few points which may be of interest. It is an exampleof a small engineering structure, which, though of no great momentin itself, illustrates the adoption of means to an end that may becapable of very great extension.
The problem, as submitted to the writer, was to construct a yachtlanding at East Island, on the exposed south shore of Long IslandSound, in connection with the construction at that point of anelaborate country residence. The slope of the beach at this point isvery gradual, and it was specified that there should be a depth of atleast 4 ft. of water at low tide. Soundings indicated that this necessitateda pier 300 ft. long. It was further specified that the pier shouldbe to some extent in keeping with the scale of the place being createdthere, and that a wooden pile structure would not be acceptable.Besides these esthetic conditions, wooden piles were rejected becausethe teredo, in this part of the Sound, is very active. At the sametime, the owner did not care to incur the expense of a masonry pierof the size involved. Also, it was desired to unload on the pier allmaterial for the house and grounds during construction, and coal andother supplies thereafter, thus necessitating a pier wide enough toallow access for a cart and horse and to provide room for turning atthe pier head.
Plate XXX.—Yacht Pier Near Glen Cove, N. Y.Comparative designs and estimates were prepared for (a) a pierof ordinary construction, but with creosoted piles; (b) a concrete pieron concrete piles; and (c) for a series of concrete piers with woodenbridge connections. The latter plan was very much the best in appearance,and the calculated cost was less than that of the pier of concretepiles, and only slightly more than that of creosoted piles, the latterbeing only of a temporary nature in any case, as it has been found thatthe protection afforded by creosote against the teredo is not permanent.
At this point on the Sound the mean range of the tide is about8 ft., and it was determined that at least 5 ft. above mean high waterwould be required to make the underside of the dock safe from waveaction. There is a northeast exposure, with a long reach across theSound, and the seas at times become quite heavy. These considerations,together with 4 ft. of water at low tide and from 2 to 3 ft. oftoe-hold in the beach, required the outer caissons to be at least20 ft. high.
To construct such piers in the ordinary manner behind coffer-dams,and in such an exposed location, was to involve expenditure far beyondthat which the owner cared to incur. The writer's attention had shortlybefore been called to the successful use of reinforced concrete caissonson the Great Lakes for breakwater construction, by Major W.V.Judson, M. Am. Soc. C.E., and under patents held by that officer. Itseemed t