WONDERS OF ENGINEERING.

Golden Bay Argus, Volume XIII, Issue 52, 26 May 1910, Page 3

WONDERS OF ENGINEERING.

t Hoisting a City. To lift a gigantic city—public Buildings, churches,, schools, shops and dwelling-houseß—l7 feet in the "air, and to do so without seriously incommoding the inhabitants or disturbing the ordinary routine of their lives, is a feat which one would ex;ptct to find chronicled only in some such work, as the Arabian Nights. Yet such a task was not only deemed practicable but was actually ac'comilished by what must be regarded as an unparalleled feat of modern engineering.

i The appalling catastrophe which ivisited Galveston, Texas, in the year |l9oo will still be fairly fresh in the [memory of most people. In that fyear a dreadful storm and tidal [ware swept over the island upon 'which Galveston is built, killing upjwards of twelve thousands of the [inhabitants. It was thought at the jtime that Galveston had been completely blotted out of existence, and /that the survivors of the mishap

would not have the hardihood to remain on the site of their ruined homes lest a recurrence of the tidal

wave should take place. But. such was not the case, for with astounding fortitude the people of the wrecked city decided that not only would they reman iu it but that they would try to rebuild it in such a manner that a calamity iof a similar nature could uot overtake it iu the future.

The tidal wave which accompanied the storm, and which wrought such fearful havoc to life and property, was calculated by eminent authorities to have swept, in a solid avalanche of water, to a height of 13 feet over the entire city, carrying fcefore it, as though they were men:

coivs, men, animals, trees and even i houses. To obviate a second visita }tion of such an alarming nature t lie citizens took counsel, and, incredible : as it may seem, decided to actually' 5 lift the entire city with its hand•some public buildings, beautiful resijdences, colossal business premises I and well-kept parks and gardens to i a height of 17 feet. Indeed, this ' ama ing project was no sooner de | clared to be, in theory, possible, than the people of Galveston pro ceeded to put it into practice. The dominating idea was, of course, the raising of the city to a height, which would give it future immunity from inroads ofv the sea. By the term City is meant, not only the houses, but th. 3 grounds upon which they jwere built—the actual site itself of the town.

j The first step in the direction of the reconstruction of the city was the (building of a great concrete wall 14 feet in height, or exactly live feet *higher than the altitude to which the tidal wave reached. The erection of this Titanic wall, which was five imiles in length and extended round the whole of the ocean side of the island, was however, only a preliminary. The next stage in this unique teat of engineering was to obtain solid and suitable material with

which to increase the height of the city itself, and with this object in view the authorities took the opinion of experts who- suggested several ways by which the material required for filling up might be obtained. The choice was finally narrowed down to two schemes. The first of these was that of importing dry soil in boats from the mainland '(Galveston is an island separated by :two miles from the Texan coast), and the second that of procuring wet or water-soaked material. The latIter plan, being not only cheaper but 'more feasible—for the matiter could taken from the bottom of the 3ea— was, after a good deal of consideration, adopted. The means by which .this could be collected " next claimed the attention of the,, engineers who, however, were equal to every difficulty, and soon they had fluite a respectable little fleet of dredges (self -filling and self-evacuat-iing) at work. Each of these dredges was calculated to have a force 'equal to a thousand horse-power,

was specia'ly built for this purpose, and was capable of raising several hundreds of tons of sand per day by a self-filling process, and then discharging this material through distributing pipes laid over the face of the island. In other words the dredges were to pump up a mixture of sand and water from the bed of the ocean and pour it into a network of pipes which would carry and deposit it over the entire face of the island to the depth of 17 feet. But it was soon found that this was not so easy a matter as had been at , first thought. The motion of the sea prevented the proper transmission of the silt (as the wet sand which the dredges brought up is called), !and much of the precious mixture [was lost. Indeed the difficulties fiof discharging the silt direct from the sea to the island soon became so apparent that the engineers de-

cided that without smooth water in which to harbour the dredges while unloading, the work could not proceed. How to obtain a clear space of i>l 'cid water in which the dredges could berth was now the difficulty with which they had to grapple. They •did not, however, shrink from this new task which the progress of the work had set them, although its achievement seemed almost insurmountable. To build an enclosed harbour would have co3t almost as much as to rebuild Galveston elsewhere. At length an alternative plan Was suggested—the building of a canal sufficiently deep and wide to be used by the dredges. This was at once adopted by the engineers, and i canal was constructed measuring learly live miles in length and over !0 feet in depth. This artificial watercourse led from the sea into the Interior of the island. The dredges were now enabled to collect the material from the sea and travel inland .through the canal which terminated

in a huge basin. In this patch of smooth water which gave them splendid berthage, the dredges unloaded themselves successfully, into the distributing pipes which, in turn, conveyed the material to the particular places where it was required. This canal (its use being now over) is being filled in* and will be raised to the increased height of the city. The material with which the city was raised to the higher level concisted, when pumped out, of about ejual quantities of sand and salt water, and the pipes through which it was forced, measured over 2,000 yards in length and vomited their filling stuff through mouths which were nearly five feet in diameter. And now we oome to the actual process of lifting the city. To do this it became apparent that every house in the town would have to be lifted bodily into the air and kept there until the ground beneath it was built up to the required level. It may here be well to state that most of the buildings in Galveston were erected upon what is known in America as the composite system, that is, they consisted of a framework of steel or wood filled

in with brick or stone. The city was raised by degrees, first one part and then another being elevated, the modus operandi being as follows : l\udei the basement of each house were thrust great lengths of wood which projected on all sides. The ends of these lengths were raised slowly by means of strong hydraulic jacks until eventually the building was raised clear of the ground, resting as it were upon an enormous wooden grating which was in turn supported by powerful upright posts. When at last the house was lifted to the proper height the pipes were laid under and near it. Then the gigantic pumps of the dredges were set in motion, and soon the pipes- were v omiting forth great masses of watery sand. Slowly, but perceptibly the ground grew higher and higher until finally the wooden supports on which the building was elevated were buried in the sand and it stood, when the material had been carefully packed under and around it on its new elevation Meanwhile the salt water oozed slowly out of the sand an I flowed into drainage cuttings which carried it away to the shore, where it finally Mowed back into the sea. It was found that the sea sand formed a splendid upper soil, rapidly growing hard, and, wh:n racked down with spades and rollers, attaining to the consistency of cement. During the period of the elevation of tha buildings the entrances to them were reached by ladders, and the side walks were constructed of wooden planking laid on trestles.

I Railway and tram tracks were also raised to the level of the new city, the sleepers supporting the lines j teing jacked up iu the same manmer as that adopted in the case of the buildings, while the filling material was pumped under them. i During the' whole time that these I amazing operations were being carried out, scarcely a single serious accident occurred. Workmen walked about under buildings rilled with workers and weighing thousands of tons, laid the pipes and retired to watch the pumps of the dredges do the work.

One of the most curious features of the great change was manifested in the arboriculture of the town. When the fine public park situated in the centre of the city was being elevated, it was of course found impossible to raise the larger trees, the roots of which extended far under the surface of Ihe ground. Nothing remained but to raise the earth around them, and .soon most of the larger trees, the foliage of which grew far up the trunks, presented the abearance of gigantic bushes, their highest branches touching the ground and in some instances lying below it. Although at first it was thought that the new soil would for a considerable time be unproductive, this proved happily not the case, as was instanced by the fact that in the high class residential portions of the oity, where the work af elevation was at first begun, the newly made gardens attached to the houses were rich' in delightful specimens of horticulture long ere the remainder of the city had been raised. At the time the project was first undertaken it was calculated that some ten years would be necessary for its achievement, but the superiority of the dredging appliances and the perfect working of the distributing pipes so vastly minimised the work that a period of but six years elapsed before it showed evident signs of completion. • The total cost of this astounding engineering feat, including the erection of the protecting sea wall, the construction of the canal and the building of the dredges, together with the multifarious operations connected with them, is said not to have exceeded the comparatively low sum of two and a quarter millions sterling. For the work carried out for this amount the inhabitants of Galveston believe that they have succeeded in placing themselves beyond the pale of another Hooding—D. J. K. Quin, in the "Weekly Telegraph."