Test III

Select the best possible answer out of the choices from the list to the statements (multiple choice):

1. Portland cement concrete is a strong, dependable … .

a. material, which can be used in tensile structural applications.

b. material, which can pull out of the casting if the anchors fail or unskilled repairs are attempted.

c. and relatively inexpensive construction material.

d. material, which can be used under calculated tensile stress.

2. When concrete is fully hardened the clamps are released and … .

a. the concrete is placed into a preloaded compressive state.

b. a load is applied within the design limit.

c. the tensile elements are coated with lubricant.

d. the stress is transferred within the rigid concrete.

3. Since the tensile elements are free to move within the casting, when curing is complete, … .

a. they can be placed into the concrete molding form.

b. they can be pulled into tension and clamped to the embedded anchors.

c. they are holding the structure together.

d. they can be adjusted to compensate for changes in loading or field conditions.

4. When a load is applied within the design limit, … .

a. it is possible to place the concrete into the molding form.

b. the concrete structural piece will never see tensile stress of sufficient magnitude to cause failure.

c. the concrete can be used in tensile structural applications.

d. stress is transferred within the rigid concrete.

5. Concrete is cast around the tensile elements and … .

a. put under calculated tensile stress.

b. allowed to cure.

c. covered with extruded polymer sleeves.

d. placed into a state of compressive stress.

Test IV

Complete the sentences by filling in the correct word that fits a statement (gap fill). Choose the appropriate words from the word bank given below.

A. tensile B. materials C. threaded D. curing

E. conduits F. grouted G. unskilled H. applications

I. inexpensive J. to compensate K. pre-tensioned L. released

1. Portland cement concrete is a strong, dependable, and relatively …… construction material.

2. When fully hardened the clamps are …… and the stress is transferred within the rigid concrete.

3. Unbonded post-tensioning is accomplished by coating the …… elements with lubricant and covering them with extruded polymer sleeves.

4. When …… is complete the tensile elements can be pulled into tension and clamped to the embedded anchors at the edges of the piece.

5. Bonded post-tensioning utilizes …… placed into the concrete molding form.

6. Lighter, stronger, longer lasting, and requiring fewer joints, pre-stressed concrete construction …… have shown how good stress can be.

7. Pre-stressed concrete has led to an explosion of …… in buildings, bridges, slabs, foundations, and roadways.

8. In …… concrete tensile elements are clamped under calculated tensile stress.

9. The tensioning elements are …… through the conduits before the concrete is cast.

10. The tensioning elements are then …… into place at the openings to permanently bond them with the structural casting.

UNIT 11