Пособия / Л.П. Даниленко, Ю.Ю. Сильман TECHNICAL ENGLISH FOR CIVIL ENGINEERS AND STRUCTURAL DESIGNERS

Task. Look through the text and give a short summary.

TEXT 3. TALL BUILDINGS

In Russia the term “tall building” describes the structure with more than 50 meters height (14 floors and more). In the structural engineering sense, the multi-storey building may be defined as “tall” when the horizontal loading due to wind or seismic effects becomes the most important consideration in design. The first high-rise buildings appeared in Russia in 1950s. Thousands of very tall buildings scrape the sky in all big cities of the country. From economic point of view, the construction of skyscrapers is certainly beneficial, especially in the areas with shortage of land.

However there are some minuses and they are rather essential: maintenance of high-rise buildings costs twice higher than ordinary buildings; high-rise buildings are negative for human health; the load on engineeringcommunication is much bigger and if a crack happens in such structure the risk of its collapse increases greatly.

Tallbuilding

There are also problems with parking place and proper system of fire protection and evacuation. Three modern achievements have contributed to making tall buildings safe and successful:

101

the design of efficient lateral load-resisting systems which are essential elements of all such structures to resistwind andseismicloads,andreducedamp vibration*;

the modern methods of computer analysis including modeling the structure for static and dynamic analysis, coupledwith modeltestinginwindtunnels*andon shaking tables*sothatbehaviourcan beaccuratelypredicted*;

the development of rapid construction methods in concrete,prefabrication techniques, drainage work* etc.

One tall building can replace a large area of low-rise buildings, and it can give chance for other constructions such as community centers, sport centers. Tall buildings are used for offices, hotels, apartment houses, hospitals, department stores etc. and often for combined use, e.g. offices/apartments.

Architects and engineers planning a tall building need to consider the following general restrictions on design:

building regulations and planning laws for the city – sometimes the maximum building height is limited;

intended occupancy – this influences the floor loading;

the transport of people is primarily vertical, requiring a central core*. The design of tall buildings was only possible following the invention of the electric lift;

fire protection of the structural frame in steel buildings is provided with sprinklers* and they have an easy and speedy evacuation system;

heating or air conditioning is essential. This requires space between floor slabs and suspended ceilings*;

services (lighting, electricity supply, telephone, computer networks, water, and waste disposal) form an

102

important part of design and must be considered at the planning stage. Services can be set in prefabricated wall and floor units during their manufacture.

The foundation of tall buildings can be expensive depending on site conditions because heavy loads are delivered onto small areas. Cellular rafts* or multi-storey basement foundations are commonly used where the space under building provides car parking. The foundations may be placed directly on the soil or be supported on piles or on caissons* under thick slabs.

Very often the erection of the tall structure has to be carried out on a restricted site. This influences the design and limits the size of components to be fabricated. Lowto medium-rise buildings can be erected with independent tower cranes located around the area. For tall buildings, erection must make use of the structure itself.

Notes:

damp vibration – затухающее колебание wind tunnel – аэродинамическая труба

shaking table – вибрационный стол, виброплощадка to predict – предсказывать

drainagework–работапоосушению

central core design – конструкция здания с центральной секцией, в которой размещены шахты лифтов и коммуникации

sprinkler – огнетушитель

suspended ceiling – подвесной потолок cellular raft – сплошной плавающий фундамент

caisson – кессон, свая большого диаметра и глубокого заложения

103

EXERCISES

Ex. 1. Give the Russian for:

Prefabrication, rapid construction technique, tall building, multi-storey structure, multi-storey basement foundation, cellular raft, caisson, wind tunnel, shaking table, vertical loading, maximum building height, planning laws, building regulations, central core, sprinkler, easy and speedy evacuation, heating and air conditioning, suspended ceiling, to reduce damp vibration, to predict accurately.

Ex. 2. Matchtwocolumns tocomplete the following sentences.

104

Ex. 3. Agree or disagree with the following statements.

1.Rapid construction techniques, prefabrication, computer modeling have greatly contributed to safe and successful erection of tall buildings.

2.Tall buildings are usually erected for such structures as schools and kindergartens, theatres and libraries.

3.Concrete framed structures and masonry are the most popular for tall buildings.

4.The invention of electric lifts gave the start to the construction of tall buildings.

5.Piles and caissons, being the basic elements of a tall building are used to support a roof.

Task. Give the written translation of the text.

TEXT 4. CONSTRUCTING A SKYSCRAPER

In Russia the term “skyscraper” describes a very tall building with a steel frame higher than 100 meters (more than 25 floors).

New methods in the design and construction of skyscrapers have been closely related to the development of computers. Engineers use computers to solve complex problems involved in such construction projects.

Skyscraper

105

Computers do this work quickly by breaking the design down into a limited number of pre-calculated elements.

Before construction begins, engineers determine the strength of the soils that will be under a new building. Using this information they can design a foundation properly. Mobile diggers (землеройные машины) begin excavating soil after the building site is cleared, leveled, and drained of water. When the excavation is finished a footing (a base) and a superstructure are built. Most steel elements used in the superstructure, such as beams, girders, and columns are brought to the site prefabricated.

The first reinforced concrete skyscraper in the world was built in 1902–1903 in Cincinnati, Ohio (the USA). It was the first time when a 16-storey structure demonstrated safety and economy of reinforcedconcreteframes for high-riseconstruction.

Concrete was chosen as a structural material chiefly for economics. It offered the equivalent of steel frames in load bearing capacity and other physical properties and it was rather cheaper. Engineers all over the world watched with great interest as construction proceeded successfully along its 16storey route. Today this building is recognized by engineers as having revolutionized the building industry.

EXERCISES

Ex. 1. Translate the following words (word combinations) into English.

Проектирование и строительство небоскребов, стальные балки, фермы, колонны, железобетонный каркас для высот-

106

ного здания, экономичность и безопасность строительства, определить твердость почвы, рассчитать нагрузку на фундамент, расчистить строительную площадку, использовать землеройные машины, начать революцию в строительной промышленности.

Ex. 2. Put these questions to your group-mates.

1.What kind of a building can be considered as “a skyscraper”?

2.When and where was the first skyscraper built? How many floors did it have?

3.What is the role of computer technologies in designing skyscrapers?

4.What did the first reinforced concrete skyscraper demonstrate?

5.What building materials are used for erecting skyscrapers?

6.What does the process of erecting skyscrapers include?

7.Which skyscraper is the tallest building in the world by the moment? What country is it situated in?

8.Is the number of storeys in skyscrapers limited?

9.Would you like to have an apartment in a skyscraper? What floor would you prefer to live on? Why?

10.Do skyscrapers make our cities’ image uglier or nicer?

107

Task. Scan the text to get the full idea of it.

TEXT 5. SHELL AND WIDE-SPAN STRUCTURES

(оболочковые и большепролетные конструкции)

Shell structures

A shell structure is a thin curved membrane or a slab usually made of reinforced concrete that functions both as a structure and a covering. The term “shell” is used to describe the structures which possess strength and rigidity due to their thin, natural and curved form such asa shell of an egg.

Shells may be round, elliptic or parabolic in cross section. Owing to the easiness of their manufacture the first type is used more frequently.

Shellstructure

Cylindricalshellsmay besubdividedinto:

single-span shells supported on two diaphragms;

multi-span shells supported on more than two diaphragms;

single-barrel shells (одноцилиндровая оболочка);

multi-barrel shells consistingof several single-barrel shells;

plain (гладкая) shells, and

ribbed(ребристая)shells.

108

The most popular diaphragms are trusses, solid beams, bowstring arches (раскосые арки) and frames. The material which suits mostly for construction of a shell is concrete because it is a highly plastic material. When mixed with water

it can take up any shape on centering or inside formwork. Small sections of reinforcing bars can readily be bent to follow the curvature of shells. Once cement has set and concrete has hardened, a membrane or a slab acts as a strong, rigid shell which serves as a structure and a covering to the building.

Advantages of shells:

very light form of construction, for a span of 30 m. required shell thickness is 60 mm.;

dead load can be reduced thus economizing foundation and supports material;

esthetically it looks better over other forms of construction.

Disadvantages of shells:

problem of shuttering (опалубка);

greater accuracy in formwork is required;

skilled labour and supervision is necessary.

109

Wide-Span structures

Wide-span buildings and structures are ones that cover area using long-span components of 36 m. and more meters. Theaters, concert halls and sports halls, exhibition halls, garages, hangars, shipbuilding factories, aircraft manufacturing and other constructions with spans of basic load bearing components of 50 meters or more belong to wide-span structures. Beam systems, trusses, frames, arches, hinged (навесной) and other building elements are used for these structures.

Wide-span structure

Advantages of wide-span structures:

strength and durability of structures;

easiness of construction.

Disadvantages of wide-span structures:

high cost compared with alternative structure systems;

problems with the number and complexity of joints;

problems of fire protection.

110