BASIC CONCEPTS IN THE ANALYSIS OF STRUCTURES

A structure is built to perform a certain function. To perform this function satisfactory, it must have sufficient strength and rigidity. Economy and good appearance are further objectives of major importance in structural design.

Stress analysis serves as an important guide in so proportioning the members of a structure that the required strength, rigidity and economy will be attained. However rigorous a stress analysis may be, the stresses which will actually occur cannot be predicted with absolute certainty. As actually build, a structure and its loading will always differ somewhat, and may differ appreciably, from the hypothetical structure which serves as a basis for stress analysis. Recognition of this fact, together with considerations of economy in time and design expense, often leads the designer to make assumption known to be correct, and approximations known to introduce errors. Only knowledge of the basic principles of stress analysis can serve as a safe basis for departure from methods more rigorously correct. The assumptions underlying the basic theory and the limitations imposed in the development of basic theorems must be fully understood and constantly kept in mind. If approximate methods arc to be introduced, they must be carefully studied in order to ascertain that they may be safely and properly applied to a given problem.

Most of the materials used in building structures follow Hooke’s law: Within a certain range dependent upon the material considered, stress and strain are directly proportional to each other. If stresses do not exceed a certain value termed tins elastic limit for the material considered, the strains will vanish if the stress is removed. Materials behaving in this manner are called elastic. Steel, wrought iron, and wood elastic, while it is permissible to consider reinforced concrete as elastic, too, provided the stresses are not too great.

When structure which are composed of elastic members and which rest elastic supports are subjected to the action of forces or to imposed deformations such as the changing of the length of a bar, there are corresponding changing of shape. The movements of points on the structure during such a change are called deflections. Distortions may or may not be accompanied by stresses in the members of structure.

 

 

VOCABULARY NOTES

 

1) rigidity – жорсткість  

2) to make assumptions – робити припущення

3) to introduce errors – виявити помилки

4) to keep something in mind – брати щось до уваги

5) wrought iron – зварювальне залізо 

6) reinforced concrete  - залізобетон

7) deflections – відхилення

8) to be accompanied - супроводжуватись

9) to vanish - зникнути

10) distortion – викривлення

 

EXERCISES

 

1) Find the English equivalents to the following word combinations and phrases;

Виконувати окремі функції; досягнути; знання основних правил; основні теореми; напруга; поведінка матеріалів; довжина брусу; еластичний; закон Гука.

2) Answer the questions:

1) Why is the structure built?

2) What is necessary to perform certain functions?

3) What is important in structural design?

4) What’s the stress analysis?

5) What can serve as a safe basis for departure from methods?

6) What do the materials follow in building?

7) How does Hooke’s law sound?

8) What materials are elastic?

9) What are distortions?

10) What are distortions accompanied by?

 

3) Translate into English :

1)Структура будується для виконання деяких функцій.

2) Економія та гарний зовнішній вигляд є подальшими важливими об’єктами в структурному дизайні.

3) Визнання цього факту з розглядом економії часу та витрат на дизайн часто ведуть до того, що дизайнер робить припущення, що є вірними та намагається виявити помилки.

4) Багато матеріалів, що використовуються в будівництві слідують закону Гука.

5) Такі матеріали як сталь, зварювальна сталь, дерево та залізобетон є еластичними.

6) Викривлення можуть або не можуть супроводжуватись стресом в елементах структури. 

 

 

Text 16

 

1)

       Integrated Building System

The procedure for erecting building structures has changed during the past few years. Field work requires workers to perform complicated tasks in a highly dangerous environment. There is a need to develop new technology to protect workers from the dangerous job environment and emphasize cost-efficiency, especially in the construction of multistory structures with repeated cycles.

The Integrated Building Systems program was developed to coordinate research projects in automated construction and connection systems. The objective of this technology is to design, fabricate, erect, and evaluate cost-effective building systems with a focus on providing a computer integrated approach to these activities.

A family of structural systems, beam-to-column connections, in both concrete and steel, will possess the capability of being erected by automated construction techniques. The technology for automated construction is heavily dependent on the use of platform cranes which are controlled by a system of six cables to allow precise movement in six directions.

The emphasis of these new designs is on cost-efficient fabrication as well as geometric configurations which provide an automatic self-guided erection feature to greatly facilitate initial placement. This feature will minimize human assistance during construction and will result in quicker, less expensive erection procedures in which workers are less susceptible to injury or fatalities.   

A model building frame was developed as a case study to compare the Integrated Building system to conventional construction. Based on the results, the range of projected cost savings was between 9% and 12%. A consortium of government, industry, and university partners is envisioned as the most effective mechanism to move these technologies from the laboratory to the field.

 

VOCABULARY NOTES :

1. the procedure – процедура

2. dangerous environment – небезпечна середовища

3. a focus – мета

4. to be dependent on – залежати від...

5. cable – кабель

6. to injury – постраждати

7. cost savings – збереження

8. to be based en – базуватися на...

9. to possess – володіти

 

EXERCISES:

1) Find the English equivalents to the following word – combinations :

- на протязі останніх декілька років.

- польові роботи

- виконувати складні завдання

- цикли, що повторюються

- дослідницький проект

- технології конструкцій

- рух

 

2) Complete the sentences with year own words :

1. The procedure for erecting building structures…

2. The Integrated Building System was developed…

3.  The technology for automated construction heavily depends on…

4.  A model building frame was developed…

5. … the range of projected cost savings…

 

3) Answer the questions :

1) What does field work require?

2) Why was the Integrated Building System developed?

3) How is a family of structural systems called?

4) What is the technology for automated construction depended on?

5) What is the use of platform cranes controlled by?

6) Why was a model building frame developed?

 

4) Translate into English :

1) Процедура для спорудження будівель змінилась протягом останніх декількох років.

2) Для польових робіт потрібні робітники, щоб виконувати складні завдання в дуже небезпечних середовищах.

3) Інтегрована будівельна система була розроблена з метою координувати дослідницькі проекти в автоматичних конструкціях та системах зв’язку.

4) Технологія для автоматичної конструкції сильно залежить від використання кранів з платформою, які контролюються системою з 6-ти кабелів.

5)Схема моделі будування була розроблена для вивчення порівняття        інтегрованої будівельної системи та звичайної конструкції.

 

 

            Text 17

ARCHITECTURE OF A HOUSE

1. Styling of a House.- When a house is to be built there are a number of things which should be given careful thought before the work is started and even before the plans for the building are drawn.

Among these may be mentioned the selection of the lot on which the dwelling is to be built, the position of the house and garage on the lot with reference to the streets and the position of the different rooms with reference to the four points of the compass­-North, South, East and West. At the same time when these things are being considered, another point must be kept in mind, that is the "style" in which the building is to be planned or, in other words, its exterior appearance. This decision should be made before plans for the house are started. The important question is also how much money can be spent on the building.

2. Designing Elevations. - An elevation is a drawing showing one side of a building. Since most houses are rectangular in plan, there will usually be four elevations. All the door or window openings and other features of construction which occur on the outside surfaces of the exterior walls can be shown on the elevations in their true dimension (to scale) as regards width and height. The elevations are practical working drawings, the purpose of which is to give to the workmen the information necessary in order that they may first set a price on the work to be done and then carry it out properly after the contract has been awarded.

The floor plans are also prepared for this purpose. The elevations must agree with the plans in giving the general dimensions of the house and the location and width of the door and window openings on each floor and other features such as balconies, porches, terraces, bay-windows, etc. Taken together the plans and elevations give the length, width, and height of every part of the house in such a way that when the various parts are built to these dimensions, they will form the completed building just as the designer saw it in his mind when he was making the drawings.

The choice of style of elevation depends upon several factors. Some are guided primarily by cost, others by desire for a certain style. Most people are concerned with the arrangement of rooms-the floor plan-and will let the exterior of the house be modified as necessary to conform to the floor plan selected. Elevations for houses in the Modernistic Style are entirely different from those for traditional houses. They usually have extremely large window areas, extending to and around the corners of the building. This with the flat roof makes almost box-like appearance, which seems strange to one accustomed to the traditional style.

Material for Elevation. - The choice of material is governed by the style and by the cost. Many styles can be worked out in any several materials or in combinations of two or three. Brick and siding, shingles and siding, brick and stucco, wood, plaster, stone and concrete-all can be handled in interesting fashion. The materials used for roofs are shingles, slate or tile. Tile and shingles are in most cases the most expensive roof materials, slate is less costly. For wall construction, brick is cheaper

than siding, and brick cheaper than stone, in most localities.

The elevations show the heights of all openings in the outside walls and the height of the window and door sills above the finished levels of the different floors. Exterior doors are apt to be 2 feet 8 inches or 2 feet 10 inches wide and 6 feet 8 inches or 6 feet 10 inches high. The larger sizes are to be applicable to the front entrance door and the smaller sizes to the rear entrance door. There is a danger in making exterior doorway too narrow, because furniture and other things must be carried through them. The front entrance door should be of a good design in keeping with the style of the house. Window openings can be of various sizes to suit the ideas of the designer. There are two kinds of windows used in houses. There are the double-hung and casement windows. The first consists of two counterweighted sashes sliding up and down; the second has one or two sashes hinged at the side and swinging horizontally in or out. There is also a bay window which is seldom seen today. Wooden shutters or blinds are often used on some of the windows of a house. Sometimes they are solid and sometimes slatted. An up-to-date house must contain one or more bedrooms for sleeping, a kitchen for preparing the meals, a dining room, a utility room for laundry and storage, and a living room for reading, writing, entertaining visitors and so forth. In addition to these rooms every present-day house contains a bathroom and may include a recreation room in the basement, and study.   

Vocabulary notes.

Reference – посилання Rectangular - прямокутний

Dimension - розмір

As regard – щодо, відносно

In order to – для того, щоб Bay-window – лихтар, еркер To work out – розробляти Shingles - галька

Stucco - штукатурка

Sash – віконна рама

Exercises

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