New Britain herald., 1917-08-17
NEW LONDON BRIDGE ALMOST COMPLETED
Lack Of Steel Holding Up Finish
 ing Touches


 masonry work on top of the piers. the sub-structure of the new Thames river bridge being built by the New York, New Haven and Hartford Rail- road company at New London is com pleted. The building of the steel su- perstructure has been delayed on ac- count of the war. The steel was con- tracted for a long time ago, but as is generally known all the steelmills in tie country are giving preference to government requirements and only such steel is being delivered at the present time as is essential for the prosecution of the war.
 Just when the New Haven will be able to obtain this steel is an uncer- tainty. It is hoped, however, that de- liveries will commence in the fall, in which case the bridge will be opened for operation in 1918. An interesting feature of the steel work and one that forcibly illustrates the high cost of railroad living, has to do with the es- timated and actual cost figures of the steel. Three engineers-one a New Haven engineer and the other two recognized authorities in bridge en- gineering-made separate estimates of the cost of the steel for this bridge Their estimates varied by less than $4,00O. But owing to the enormous increase in steel prices, the New Haven railroad will have to pay ap- proximately $2O0,ooo more than any of these engineers estimated.
 The section of the New Havens main line at New London has long been the "pinching" point in the system Since 1908 the old Thames river bridge has been operated as a single track structure, due to the great i&srease in weight of train equipment since the building of the bridge. The bridge was constructed in 18SS-89 in order to provide a direct line between New York city and Boston via New London and Providence. Previously trains were ferried across the Thames river at New London. The opening of the bridge in 1889 was of as great importance to New England in those days as the opening of the He'll Gate bridge nearly thirty years later.
 Old Bridge Aroused Admiration.
 The remarkable strides railway con- struction has taken in the past 30 ! years is disclosed when it is remem- bered that in 1889 the Thames river bridge was considered one Of the great l engineering feats of the period! The l draw span of 503 feet was x&ts that l time the biggest in the worlds
 While the old bridge is some '36 1 feet longer than the new structure l will be, it is considerably lighter. The old bridge is 1,425 feet long. while the new one will be 1887 feet. / The weight of the old bridge is 2,40O tons. and the new one 5,225 tons. The old structure was made of open hearth anN Ressmer carbon steel of an elastic l strength of about 24,000 pounds per square inch. The new bridge will be of silicon steel with an elastic strength of not less than 45,000 pounds per square inch. The old bridge is of the draw or swing span type, the span be- ing operated by steam engines. The new bridge is of the bascule or lift span type, the span being operated by | electric motors. The motors will be in duplicate, and power will be taken from three sources to insure against mishap and delay.
 The new bridge is being constructed to carry the heaviest loading now known to railway managers or con- templated in the future. The foun- dations have been constructed for four-track superstructure, but for the ! present a two track superstructure will meet all requirements.
 In building the four piers for the substructure open-well dredging was
  them, and the pneumatic caisson process for the other. The old bridge is placed on piles but it was not | practical to use piles for the new bridge as the soft river bottom loam or clay would not give adequate sup 1 port to a pile cluster in a degree l requisite for this bridge. The sub- l soil is mud CT soft clay for 50 to a 100 feet, water being 20 to 50 feet 1 deep. Below the mud is firm gravel 1 to support the deep piers. The cen- tertpiers adjacent to the channel, go ! down to a depth of 130 feet below the l water, in order to rest upon suitabl l foundation material. Above the tide 1 level the piers and abutments extend l 25 feet high in an artistic design. | They furnish the support for the steel l pedestals of the bridge trusses which l are to carry the railway tracks The 1 exIeem dimensions of the foundations 1 of sehe piers are AZ feet by 98 feet. It required about 46,O0O cubic yards 1 of concrete to construct these piers. 1
 Building Piers Hard Task.
 The construction of the piers rep resented an unusually difficult and l costly operation. Many unusual con- ] ditions were overcome by the engin- | eers in charge. In building the east l pieT, for example, rock was found at | practicable depths to support the pier, l but the rock shelves down in the up- | stream direction so abruptly that | three separate caissons had to be | used to provide the support for the l pier at the different depths it touches l the rock. l
 Over s1,OOO,0o0 has already been l expended on the Thames River 1 bridge The substructure, however, | represents the most difficult and eX-