BUILDING CONSTRUCTION: Chapter 4

A 20 ft high column shortens by 0.6 in under a load. What is the resulting strain in the column? a. 0.0020 b. 0.0020 in c. 0.0025 in d. 0.0025 e. None of the above

d. 0.0025

In most materials, the safety margin for compressive stress and bending stress is the same a. True b. False

b. False

In a typical stress strain diagram of a material, the stress is generally plotted along the vertical axis? a. True b. False

a. True

Brittle Materials

do not deform much before failure, but failure is sudden and catastrophic

Which of he following beam cross section is structurally more efficient in bending? a. Rectangular (solid) section b. I section

b. I section

Ultimate Compressive Strength is the load at failure

Compressive Strength = load at failure / area of the cylinder

Modulus of Elasticity

E = Stress / Strain

Define stress

The force acting on a unit cross sectional area f = force/area

The primary purpose of the longitudinal steel bars in a reinforced concrete beam is to overcome the weakness of concrete in tension a. True b. false

a. True

The stress strain diagram of mild steel is nearly a straight line up to the yield point? a. True b. False

a. True

Concrete is a. an elastic material b. a plastic material c. an elastic plastic material d. none of the above

a. an elastic material

The material in an arch is primarily in: a. compression b. tension c. both tension & compression d. shear e. none of the above

a. compression

In a steel column that rests on a concrete footing, the area of the bearing plate used is generally a. greater than the cross sectional area of the column b. equal to the cross sectional area of the column c. smaller than the cross sectional area of the column

a. greater than the cross sectional area of the column

The primary purpose of ties in a reinforced concrete columns is to a. prevent the buckling of vertical reinforcement in the column b. prevent the crushing of concrete c. increase the shear resistance of the column d. none of the above

a. prevent the buckling of vertical reinforcement in the column

When we determine the strength of concrete using the test specimens, we determine the concrete's a. ultimate compressive stress b. ultimate tensile stress c. ultimate shear stress d. modulus of elasticity e. all of the above

a. ultimate compressive stress

Which gives greater warning before failure? a. A brittle material b. A ductile material

b. A ductile material

Which of the following beam cross sections is structurally more efficient in bending? a. Rectangular (solid) section b. Tubular section

b. Tubular section

A material that is weak in tension a. strong in shear b. weak in shear c. no relationship between the shear and tensile strengths of a material

b. Weak in shear

The allowable stress in a material is generally a. equal to ts ultimate stress b. less than its ultimate stress c. greater than its ultimate stress d. none of the above

b. less than its ultimate stress

Modulus of elasticity refers to how a. strong a material is b. stiff a material is c. elastic a material is d. serviceable a material is e none of the above

b. stiff a material is

A material that is weak in tension is a. strong in bending b. weak in bending c. no relationship between the tensile and bending strengths of a material

b. weak in bending

In a simple 3 member truss consisting of 2 rafters and a tie, each member is in: a. compression b. tension c. either tension or compression d. shear e. both tension and compression

c. EITHER tension or compression

In a suspension bridge, which members(s) is (are) in compression? a. Suspension cable b. Hanger cables c. Support pylons d. both suspension cable and hanger cables e. None of the above

c. Support pylons

When a cable or rope is compressed by a force, what is the the compressive stress in it? a. equal to the force applied b. force divided by the cross sectional area of the rope c. Zero d. Infinite e. None of the abve

c. Zero

Low carbon (mild) steel is a. an elastic material b. a plastic material c. an elastic-plastic material d. none of the above

c. an elastic-plastic material

The bearing strength of a material is closely related to its a. bending strength b. tensile strength c. compressive strength d. modulus of elasticity e. none of the above

c. compressive strength

The bending stresses along the neutral axis of a beam are a. minimum b. maximum c. zero d. none of the above

c. zero

A rectangular column measuring 12in x 12 in in cross section carries a load of 18kips. What is the stress in the column? a. 18 kips b. 18 ksi c. 2.25 ksi d. 125 psi e. None of the above

d. 125 psi

The horizontal blocking in wood studs helps prevent a. compressive failure of studs b. shear failure of studs c. tensile failure of studs d. buckling of studs

d. buckling of studs

The stirrups in a reinforce concrete beam are used to a. increase the strength of the beam in bending b. reduce the deflection of the beam c. increase the durability of the beam d. increase the strength of the beam in shear e. none of the above

d. increase the strength of the beam in shear

In relation to its compressive strength, the tensile strength of concrete is a. much higher b. slightly higher c. nearly the same d. much lower e slightly lower

d. much lower

What is the yield stress of grade 60 reinforcing steel? a. 60 lb b. 6,000 psi c. 6,000 lb d. 60 psi e. None of the above

e. None of the above Grade 60 is KSI

The units of modulus of elasticity are a. psi b. ksi c. Pa d. GPa e. all of the above

e. all of the above

The test specimen used for determining the compressive strength of concrete in the United States is a a. cube measuring 12x2x12 b. cube measuring 6x6x6 c. prism measuring 6x6x12 d. cylinder measuring 12 in diameter and 6 high e. cylinder measuring 6 in diameter and 12 high

e. cylinder measuring 6 in diameter and 12 high

Axial Stress

is uniform over the entire cross section

Rigid Body

one that does not deform at all under the action of loads

Ductile Materials

produce large deformation before failure. Also malleability

Bending

produces compression in one half of a member and tension in the other half

Strain

the change in length divided by the original length