Columbia University Libraries Digital Collections: The Real Estate Record

Real estate record and builders' guide: [v. 93, no. 2409: Articles]: May 16, 1914

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REAL. ESTATE AND NEW YORK, MAYiie, 1914 i:!lili:il3,:;li;:!e;t:i:l:r:li;::;:J::;. :i:ilii:!IJ SUB-SURFACE STRUCTURES IN NEW YORK Assessed Values For Franchise Purposes Aggregate About $500,000,000 —^About 3,800 Miles of Conduits and Mains in Manhattan Alone .■■lit By CHARLES N. GREEN* '' IBIIIIIiaillllllllllillllllllliailllllB^^^^^^^ ......i''''Ti:i»lii[lll!lllll!lll!!illllllllillilllllllllillllllilllll PART I. FEW people, including engineers, realize the importance of under¬ ground structures' in our everyday life, and the need for making a more intelli¬ gent use of underground space. The reason is that the increase in the num¬ ber and variety of public utilities has been so great and so rapid that they are now lying in confusion beneath the street surface in the congested districts of the larger cities. As illustrating the importance of sub¬ surface structures, I might say that the assessed value for franchise purposes of the utilities occupying the streets of New York City is about $500,000,000, and the companies owning these structures are capitalized at about twice this amount. This, of course, includes neither the water and $24,000,000 for sewer systems, which are municipally owned and oper¬ ated, nor street paving, which is largely affected by structures beneath it. In Manhattan alone there are nearly 500 miles of street, with over 1,400 miles of gas mains, over 900 miles of water mains, and nearly 500 miles of sewers of all kinds', and over 1,000 miles of trench for high and low tension electric service. The laying and maintaining of street structures constitute one of the serious problems which confront the distribu¬ tion department of all companies and bureaus that are compelled to use the streets' for their distribution systems. The importance of these structures is only brought to our attention when something goes wrong—either our wa¬ ter supply is temporarily cut off, our sewers clogged, gas pipes are frozen, or some accident has occurred and our telephone, electric light or subway is' temporarily out of commission. The needs of primitive man were few, very few, indeed, and until he began to herd together in camps, little but his personal needs occupied his attention. When he began to build a permanent home, and his own tribe, clan, family or those with a common interest built near him, it became necessary to have adenuate water supply, and to dispose of bodilv and camp or town wastes. In his further development, the higher he rose in civilization, the greater became his necessities, both actual and those which contributed to his convenience and lux¬ ury, and after the water and sewers there followed artificial light, means of transportation for the community, heat, telegraph, telephone, refrigeration, pneu¬ matic tubular despatch, compressed air or hydraulic pressure for ventilation or power. It was a wise town which an¬ ticipated its future needs both in the general plan of its streets and in their width. The lack of such fnrcsiu'ht has inspired the present day and generation with the idea of city planning as a meas¬ ure tending to economy, convenience and be.iuty. Water was the first necessity, and we find the Greeks and Romans building •Lecture delivered at meeting of American Society Enelnecrs, Architects and Constructors, in United Engineering Building, May 12, DO YOU appreciate the extent and scope of the sub-surface improve¬ ments in New York City? The en¬ tire municipality is honeycombed with pipes and wires, all having their uses, and playing a vital part in daily life. The Record and Guide pub¬ lishes today the first installment of an article by Charles N. Green deal¬ ing 'with this subject and showing the construction of these various im¬ provements and their groviring needs. Millions of dollars have been invest¬ ed by private corporations as well as the city in sub-surface work. One of the difficulties encountered is that not only must present-day require¬ ments be complied with but pro¬ visions must be made for years to come, in order that the highways will be undisturbed. The engineer¬ ing difficulties encountered are also dealt 'with in Mr. Green's article. extensive systems of water supply long before the dawn of Christianity. Euro¬ pean and American cities have followed in later times much the same plans used by the Greeks and Romans. The supply of water for New York City was first from wells, but about the year 1800 pipes were laid by the Manhattan Water Company to supply the city with water. These pipes were logs of wood, bored out and reinforced at each end with an iron band driven into the end of the log. First Water Supply. In most cases' the municipality has built, owned and operated its own water and sewer systems, but there are many places where both are still owned and ooerated by private companies. The reverse of this condition is true of nearly all the other public utilities. The first gas mains were laid about 1823. The gas and water pipes of this early date had shallow hubs and were. cast horizontally, ■ differing from_ the present day practice. Some of this old pipe is still in service in the city. The water pipes are still laid with poured lead joints, which until recently was also true of gas pipes. Gas pipes now are more generally laid with lead wool, which makes a joint that is less liable to leak. Water pipes 20 inches' and larger in diameter should be laid with air cocks at high points', and a blow-off at low points; gas mains should drain to drips which are pumped out periodically. The first sewers were built about 200 years apro, but nearly all of them have 'been built since 183S. They were built in the center of the street, so that they could be easily reached from either side, unless the streets were so wide that the laterals cost more than enough to bal¬ ance the cost of another sewer. In the case of water and gas mains the cost of house service is so much greater that in most instances' mains have been laid on both sides of the street. Franchises were granted to so many gas companies, each restricted to a small area, and in most cases overlapping or covering the same territory, that in some streets there were, ten years ago, five or six companies owning mains on both sides of the same street. Today it is not uncommon to find three com¬ panies in the same street, each with mains large enough to supply the total demand. Besides these service mains there are in various streets large supply or distribution mains and pumping mains. These only feed the service mains or run from the works to a holder, or from holder to holder, and serve to maintain the required pressure. Advent of the Horse Car. Horse cars were the first public con¬ veyances occupying a permanent posi¬ tion in the streets. Whether or not the rails consisted of strap iron on wooden stringers, I do not know, but such con¬ struction was used in some cities. Some¬ times the ends of the straps would be¬ come loose, curl up, and perhaps run up through the bottom of the car, to the p-reat inconvenience and danger to pas¬ sengers. The next development was, I believe, the cable, with a great deal of underground construction for sheave- pits, etc. Then the overhead trolley superseded many horse car lines, and the underground trolley superseded the cable. The underground trolley was, I believe, first used in this country in 1895 and 1896. It had formerly been used in Budapesth, but has been modi¬ fied to suit climatic conditions here. Its underground construction is simpler than the cable railway. In the construc¬ tion of the Broadway subway a wheel-pit was encountered at Houston street which extended from the cable buildin.g to the east side of the easterly track, thus tak¬ ing up more than half the street. This pit was about 20 feet below the street surface to the floor, and was used as a wheel-pit to turn the cables coming from the basement of the cable build¬ ing which was used as a power house. The latest development has been the storage battery cars, but the street work of the track does not differ materially from that used for horse cars. There are in the city many miles of track on which cars are not operating for pas¬ sengers, but solely to hold down the franchise. They occupy space which could be used to far better advantage. Steam Pipes Installed. About 1880 the first steam pipes were laid under the streets of New ^'ork. These pipes are of wrou,ght iron and vary from 4 to 20 or 24 inches in diam¬ eter. Originally they were laid in wooden logs, and later in a brick con¬ duit with a wooden cover and the space around the pipe filled with mineral wool. In the modern form the pipe is covered with air cell coverin.?. The conduit is built of hollow tile and the space filled, a.s' before, with mineral wool. Instead of a plank top, half a sewer tile is used, making an arched roof. On account of the need of expansion joints, valves, and to prevent radiation of heat street surface, these placed deep in