Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
МУ_English_II_k.doc
Скачиваний:
0
Добавлен:
01.04.2025
Размер:
238.08 Кб
Скачать

In turn, basic load combinations are subdivided into two groups.

The first group includes dead, long-time and one short-time live load, the second contains dead, long-time and two (or more) short time live loads.

When structures are designed to resist special load combinations, short-time loads or the respective forces should be multiplied by a combination factor of 0.8, except the cases covered by specifications for structures in earthquake regions. The special load proper should be taken into account without any reduction.

Vocabulary notes

Dead load – постійне навантаження Live load – переменне навантаження Pressure - тиск

Prestressed concrete – попередньо напруженний бетон Storehouse - склад

Archive - архів

Total value – сумарна вартість Average value – середня вартість Rated value – нормована вартість To evaluate – оцінювати Displacement – переміщення Earthquake – землетрус

Exercises

1. Find in the text English equivalents to the following word combinations:

Згідно з тривалістью, довготривалі навантаження, короткочасні навантаження, тиск грунту, нерухоме обладнення, запасна частина, раптові зміни, осідання грунту, чинити опір навантаженню.

2. Answer the following questions:

1. What groups are loads divided into according to their duration? 2. What groups are live loads subdivided into? 3. What are dead loads? 4. What do long-time loads include? 5. What loads do short-time loads include? 6. How are the basic values for dead loads deduced? 7. How are the basic values for live loads deduced? 8. What do basic load combinations consist of?

3. Try to reproduce all the words and expressions from the text connected with the civil engineering.

Text 21 approaches to testing the deformability of cement repair materials.

Durability of a repaired concrete structure and its service life depends on the behavior and coexistence of a repair material and the existing concrete substrate combined together in a composite system, in a repaired concrete structure. The most serious deterioration processes that lead to repaired failures are caused by cracking of the repair material. Restrained contraction of repair materials, the restrained being provided through bond to the existing concrete substrate, is a major factor leading to cracking and failure of the repair.

The safety and durability of the repaired structures cannot he realized without a comprehensive knowledge of the material's properties that determine its deformational characteristics and, therefore, its capability to resist cracking. Material manufactures tend to use different tests and standards to evaluate the performance of their products. Many standard tests used are modified arbitrarily. Some modifications are deficient or providing unrealistic results. This situation has resulted controversy and confession in the selection and specification of repair materials. Variations of the test methods including size of the specimens, restraint conditions, curing time of initial readings, temperature and relative humidity limitations, and test duration further complicate the interrelation of comparative results and properties indicated in manufacturer's data sheets.

Among the major problems facing us at the beginning of the New Millennium are the enormous infrastructural needs of a rapidly urbanizing world, the deterioration of concrete structures, the necessity to repair deficient concrete structures, the premature failure of repairs, and the need to improve repair durability in a cost- expensive way,

The long term performance of repaired concrete structures can be achieved by proper existing condition evaluation, adequate design details and specifications, selection of suitable repair materials, improved construction practices and quality control.

Unfortunately the present state of concrete and other cementing composites is such that they are permitted, with our" help ", to extensively change their volume, crack and misbehave, especially when exposed to severe environments.

Difficulties with selecting cementing repair materials have resulted not only from the lack of performance criteria, but also from the lack of reliable standards for testing material properties effecting their deformability sensitivity to cracking.