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Валерия
Эксперт по сдаче вступительных испытаний в ВУЗах
Задание -2- Прочитайте и письменно переведите текст на русский язык.
Building the Tower Bridge The most famous example of the bascule bridge is the Tower Bridge across the River Thames in the heart of London. Engineers were able to build this type of bridge without interrupting traffic on the great commercial waterway. THE problem of building a bridge over a busy river with low banks so that shipping is not obstructed is one that taxes the resource and ingenuity of the engineer. He surmounts the difficulty by resorting to the opening type of bridge, of which the main types are the drawbridge or bascule bridge, turning about a horizontal axis; the swing bridge, turning about a vertical axis; the rolling lift bridge and the vertical lift bridge. One of the most famous examples of the bascule type is the Tower Bridge, which spans the River Thames just below London Bridge. It is the most distinctive of London’s bridges and its construction was a masterly engineering achievement. The building of the Tower Bridge came about because the development of cross-Thames traffic had far outstripped the capacity of the existing bridges. By the year 1870 the position had become serious, and between 1874 and 1885 some thirty petitions from various public bodies were brought before the authorities urging either the widening of London Bridge or the building of a new bridge. A two days’ census taken during August 1882 showed that the average traffic for twenty-four hours over London Bridge — which at that time was only 54 feet wide — was 22,242 vehicles and 110,525 pedestrians. A committee was appointed to consider the matter and to report upon the different plans that had been proposed. These included schemes for low-level bridges with swing openings of various kinds, and high-level bridges with inclined approaches or with lifts at either end. There was also a proposal for a railway line to be built at the bottom of the river and to carry a travelling staging with its deck projecting above high-water level. Proposals for a subway and for large paddle-wheel ferry boats were also considered. None of these schemes was approved. In 1878 Horace Jones, the City architect, put forward a proposal for a low-level bridge on the bascule principle — that is, a bridge on a level with the streets with two leaves or arms that could be raised to let ships pass up and down the river and lowered to let vehicles pass to and fro across the waterway. Successful bridges of this type already existed, though on a much smaller scale, at Rotterdam and Copenhagen. “Bascule” is derived from the French word for “see-saw”, and the bascule bridge is a kind of drawbridge which works on a pivot and has a heavy weight at one end to balance the greater length at the other. This was the type of bridge finally decided upon, and it has proved a great success. The Tower Bridge is, perhaps, the most famous bascule bridge in the world, and its working from the day it was first opened to the present has been perfect, far exceeding the hopes even of its most enthusiastic advocates. An Act of Parliament empowering the Corporation of the City of London to build the bridge was passed in 1885. Horace Jones was appointed architect and was knighted, but died the same year, and Mr. (afterwards Sir) John Wolfe Barry was appointed engineer. The work was divided among eight different contractors. Among them Sir John Jackson was responsible for the piers and abutments, Sir William Arrol for the steel superstructure, Sir W. G. Armstrong, Mitchell and Co, Ltd, for the hydraulic machinery and Perry and Company for the masonry superstructure. Work was started on the bridge in April 1886, the foundation stone being laid, on behalf of Queen Victoria, by the Prince of Wales, afterwards King Edward VII. The bridge was to have been finished by 1889, but difficulties arose and Parliament was twice asked to extend the time for the completion of the work. It did so, and the bridge was eventually opened on June 30, 1894, having cost about £1,000,000 sterling to build, a remarkably small sum for such a bridge in such a position. The total length of the bridge, including the approaches, is half a mile. The roadway has a width of 35 feet and on either side of it is a footway 12½ feet wide. The total height of the towers on the piers, measured from the level of the foundations, is 293 feet. 140 Feet Headway for Ships In building the bridge there were used about 235,000 cubic feet of Cornish granite and Portland stone, 20,000 tons of cement, 70,000 cubic yards of concrete, 31,000,000 bricks and 14,000 tons of iron and steel. The bridge is a combination of the suspension and bascule type. The width of the river between the abutments of the bridge on the north and south sides is 880 feet. This is crossed by three spans. The two side spans, each 270 feet long, are of the suspension type. They are carried on stout chains that pass at their landward ends over abutment towers of moderate height to anchorages in the shore. At their river ends the chains pass over lofty towers which are themselves connected at an elevation of 143 feet above high water. Heavy tie bars, at the level of the connecting girders, unite the two pairs of chains so that one acts as anchorage for the other at the centre. The central span has two high-level footways side by side, and one low-level roadway. High-level girders carry the upper footways, which are reached by hydraulic lifts or staircases in the main towers. The roadway, or central opening span, is 200 feet long and consists of two bascules or leaves. The Tower Bridge Act laid down that when the bridge was open there should be a clear headway at high tide between the water and the high-level footways of 135 feet and a headway of 29 feet when the bridge was closed. These dimensions were exceeded in practice, the open height being 5 feet and the closed height 6 in greater than had been prescribed. This was above high-water level. The greatest extreme between high and low tide at Tower Bridge is 25 feet. The Act further stipulated that the piers were to be 185 feet long and 70 feet wide. There was also a clause making it compulsory to maintain at all times during the building of the bridge a clear waterway 160 feet wide. This stipulation made it impossible for the two piers to be built at the same time, because the staging would have occupied far too much of the river space. As the use of timber cofferdams was prohibited, the builders had to rely on caissons. The restricted area which they were allowed for their staging, 130 feet by 335 feet, did not permit the use of one caisson extending the full length of a pier. The builders therefore adopted a system of small caissons covering the area of the pier. By this means it was possible while building one of the piers to be working also at the shore side of the other. Had both piers proceeded simultaneously a saving of thirteen or fourteen months might have been effected. The piers of the Tower Bridge are much more complicated structures than the piers of an ordinary bridge. In addition to supporting the towers carrying the overhead girders for the high-level footways and the suspension chains of the fixed spans, they also house the counterpoise and the machinery which operates the bascules. Triangular Caissons The caissons used for securing the foundation of the piers consisted of strong boxes of wrought iron, without either top or bottom. To secure a good foundation it was found necessary to sink them to a depth of about 21 feet into the bed of the river. There were twelve caissons for each pier. On the north and south sides of each pier was a row of four caissons, each 28 feet square, joined at either end by a pair of triangular caissons, formed approximately to the shape of the finished pier. There was a space of 2½ feet between all the caissons, this being considered the least dimension in which men could effectively work. The caissons enclosed a rectangular space 34 feet by 124½ feet. The space was not excavated until the permanent work forming the outside portion of the pier had been built, in the caissons and between them, up to a height of 4 feet above high-water mark. The method adopted in building and sinking the caissons was unusual. First came the building of the caisson upon wooden supports over the site where it was to be sunk. The caisson was 19 feet in height and it was divided horizontally into two lengths. The lower portion was known as the permanent caisson and the upper portion, which was removable when the pier was completed, was called the temporary caisson. The object of this upper portion was simply to keep out water while the pier was being built. When ready the supports were removed and the permanent caisson lowered to the river bed (this had previously been levelled by divers) by means of four powerful screws attached to four lowering rods. After the caisson had reached the ground various lengths of temporary caisson were added to the permanent section, till the top of the temporary portion came above the level of high water. The joint between the permanent and the temporary caissons was made tight with indiarubber. Divers working inside the caisson excavated first the gravel and then the upper part of the clay forming the bed of the river. As they dug away the soil, which was hauled up by a crane and taken away in barges, the caisson gradually sank until its bottom edge penetrated some 5 feet to 10 feet into the solid London clay. London clay is a firm watertight stratum, and when the desired depth had been reached by the caisson it was safe to pump out the water, which up to this time had remained in the caisson, rising and falling with the tide through the sluices in the sides. The water having been pumped out, navvies were able to get to the bottom of the caisson and to dig out the clay in the dry. Additional lengths of temporary caisson were added as the caisson sank, so that at last each caisson was a box of iron 57 feet high, in which the preparation of the foundations could be made. The caisson having been controlled from the first by the lowering rods and screws, its descent any farther than was desired was easily arrested by the rods when the bottom of the caisson was 20 feet below the bed of the river. The clay was then excavated 7 feet deeper than the bottom of the caisson, and outwards beyond the cutting edge for a distance of 5 feet on three of the four sides of the caisson. In this way not only was the area of the foundations of the pier enlarged but, as the sideways excavations adjoined similar excavations from the next caissons, the whole foundation also was made continuous. All the permanent caissons, with the spaces between them were then completely filled with concrete, upon which the brickwork and masonry were begun in the temporary caisson and carried up to 4 feet above high water. The preparation of the foundations was a long and troublesome task because of the extent of the river traffic, which made it difficult to berth the necessary barges. On two occasions “blows” occurred which hindered the operations. When the cutting edge of one of the caissons had reached a depth of 16 feet beneath the river bed, water rushed into the caisson through a rent in the clay. The caisson had to be lowered still farther to seal the opening when the water was pumped out.Задание -3- Изучите структуру сопроводительного письма о приеме на работу (Letter of Application) и составьте собственное письмо, следуя приведенному образцу.
Сопроводительное письмо к резюме (Letter of Application) – важный документ, который необходим при трудоустройстве в зарубежную компанию или отечественную фирму с определенными требованиями к соискателям. К составлению сопроводительного письма необходимо отнестись со всей ответственностью. Сопроводительное письмо к резюме оформляется по общепринятым критериям. В частности:- На отдельном бланке при отправлении в распечатанном виде.
- В теле электронного письма в формате MS Word.
- С реквизитами, заголовком, датой, а также наименованием и адресом получателя, оформленными в соответствии с правилами по написанию деловых писем.
Malik Rabb
1234, West 67 Street
Carlisle, MA 01741
(123)-456 7890
Date: June 1st, 2008
Mr. Ronaldo Hiring Manager ABC Constructions 12345, Park Avenue South New York, USA 12345 Dear Hiring Manager, I was very excited to see your posting for the Civil Engineer position at River Tech. I have been working in the engineering field for several years, and during that time I have been a part of multiple projects, including ones that focused on the maintenance of several roads and the design of Cloud Clearwater Bridge. I am particularly detail oriented, and I have always been praised for my ability to foresee potential problems and make proactive plans. In my previous role as Civil Engineer, I was responsible for examining the stability of the bridge that we were building and assessing how it would withstand an earthquake. I also helped with the maintenance and upgrading of several roads that needed drainage to make the roads safer for travel and improve the longevity of the road’s surface. I am not only attentive to detail when designing and maintaining roads and bridges. I am also attentive to the criticism of others, and I highly value feedback that will make my projects run more smoothly. I appreciate straightforward yet relaxed professional interactions, and I aim for that dynamic with all of my colleagues and outside contacts. I sincerely look forward to further discussing the role of Civil Engineer at River Tech. I’m also excited to hear more about some of the projects that River Tech has been involved in as well as any projects in the foreseeable future. I appreciate your time in considering me for this position. Sincerely, Malik Rabb
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