Building Construction: Chapter 3 & Chapter 4

According to the geologists, the earth's surface is composed of several segments that are called what?

Tectonic plates

Concrete is what type of material?

an elastic material

Highest wind speeds are usually obtained in?

Tornadoes.

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

b. I-section

A material that is weak in tension is: a. strong in shear b. weak in shear

b. weak in shear

The roof live load in a building is generally: A. Less than the floor live load. B. Greater than the floor live load. C. The same as the floor live load.

A. Less than the floor live load.

The design wind speed is also referred to as the?

Basic wind speed

Modulus of elasticity refers to how _____ a material is.

Stiff

When a cable or rope is compressed by a force, what is the compressive stress in it?

Zero

A material that is weak in tension is: a. strong in bending b. weak in bending

b. weak in bending

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

c. zero

The loads on a floor are generally expressed in?

lb/ft²

The total approximate dead load on a floor in a typical wood frame residential building is?

10 psf

For most of the U.S. the design wind speed for an average-risk building is:

115 mph

The design wind speed for a location is the peak.

3-s gust speed

The floor live load in a residential occupancy is generally assumed to be?

40 psf.

The total approximate gravity load on a floor in a typical wood frame residential building is?

50 psf

Which of the following loads can be estimated with the greatest certainty? A. Dead loads B. Live loads C. Wind loads D. Earthquake loads E. Snow loads

A. Dead loads

Which of the following roofs will you consider the effect of rain load? A. Roof with a parapet B. Roof w/o a parapet

A. Roof with a parapet

Low-carbon (mild) steel is what kind of material?

An elastic-plastic material.

Which of the occupancies has the highest floor live load? A. Classrooms B. Hotel guest rooms C. Library stack rooms D. Library reading rooms E. Offices

C. Library stack rooms

One a leeward wall, the wind pressure: A. increases with height above the ground. B. decreases with height above the ground. C. is almost constant with height above the ground.

C. is almost constant with height above the ground.

The design wind speed for an average-risk building at a location has a probability of occurrence of: A. once in 300 years B. once in 200 years. C. once in 100 years. D. once in 50 years. E. none of the above.

E. none of the above.

With respect to wind pressure, a building site is classified in terms of?

Exposures B, C, and D.

(T/F): An average tornado strikes a larger area on the ground than a hurricane.

False

(T/F): For wind blowing along one of the two major axes of a rectangular building, the leeward wall is subjected to positive (toward-the-wall) pressure.

False

(T/F): For wind blowing along one of the two major axes of a rectangular building, the side walls are subjected to positive (toward-the-wall) pressure.

False

(T/F): In most materials, the safety margin for compressive stress and bending stress is the same.

False

(T/F): Roof live load is a function of the building's occupancy.

False

The two main categories under which all building loads may be classified are?

Gravity loads and Lateral loads.

(T/F): Everything else being the same, a building constructed of heavyweight materials is subjected to a greater earthquake load than a building constructed of lightweight materials.

True

(T/F): For wind blowing along one of the two major axes of a rectangular building, the windward wall is subjected to positive (toward-the-wall) pressure.

True

When we determine the strength of concrete using the test specimens, we determine the concretes what.

Ultimate compressive stress

The region of the U.S. that is relatively more earthquake prone is?

Western U.S.

In a building whose structural system consist of columns, beams, and floor and roof slabs, the columns are spoaced at 40 ft on center in one direction and 25 ft on center in the other direction. What is the tributary area for an interior column? a. 1,000 ft² b. 1,000 ft c. 500 ft² d. 250 ft² e. None of the above

a. 1,000 ft² math: 25 * 40 = 1,000

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 column is to: a. prevent the buckling of vertical reinforcement in the column b. prevent crushing of concrete c. increase the shear resistance of the column

a. prevent the buckling of vertical reinforcement in the column

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

The allowable stress in a material is generally: a. equal to its ultimate stress b. less than its ultimate stress c. greater than its ultimate stress

b. less than its ultimate stress

A reinforced concrete beam measures 12 in. x 24 in. in cross section. If the density of reinforced concrete is 150 lb/ft³, the weight of the beam is: a. 450 lb/ft. b. 350 lb/ft. c. 300 lb/ft. d. 300 lb. e. 300 lb/ft³

c. 300 lb/ft.

In a suspension bridge, which member(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

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

c. buckling of studs

The bearing strength of a material is closely related to its: a. bending strength b. tensile strength c. compressive strength

c. compressive strength

In a simple three-member truss consisting of two rafters and a tie, each member is in: a. compression b. tension c. either tension or compression d. both tension and compression

c. either tension or compression

The material in an arch is primarily in?

compression

A 20ft 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 math: convert 20 ft to inches (240") .6/240=0.0025

A rectangular column measuring 12 in. x 12 in. in cross section carries a load of 18 kips. 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 math: (12*12=144) (18/144=.125)

In a building whose structural system consist of columns, beams, and floor and roof slabs, the columns are spoaced at 40 ft on center in one direction and 25 ft on center in the other direction. What is the tributary area for a corner column? a. 1,000 ft² b. 1,000 ft c. 500 ft² d. 250 ft² e. None of the above

d. 250 ft² math: 12.5 * 20 = 250 (half of the distance for the columns)

The design snow load on a roof is a function of: a. ground snow load of the location. b. roof slope. c. wind exposure classification of the site. d. all of the above. c. both (a) and (b).

d. all of the above.

The stirrups in a reinforced 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 lb c. 6,000 psi d. 60 psi e. None of the above

e. None of the above *it's 60ksi

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

An earthquake measuring 7.0 on the Richter scale is: a. twice as strong as a 6.0 earthquake. b. 10 times stronger than a 6.0 earthquake c. 100 times stronger than a 6.0 earthquake. d. 500 times stronger than a 6.0 earthquake. e. none of the above.

e. none of the above.

The number of mild (minor to very minor) earthquakes occurring on earth is almost: a. 1 or 2 per year. b. 10 to 20 per year. c. 100 per year. d. 1,000 per year. e. several thousand per year.

e. several thousand per year.

The loads on a column are generally expressed in?

lb.

The loads on a beam are generally expressed in?

lb/ft

The test specimen used for determining the compressive strength of concrete in the U.S. is a?

6 in. diameter x 12 in. high cylinder

(T/F): In a typical stress-strain diagram of a material, the stress is generally plotted along the vertical axis.

True

(T/F): The primary purpose of longitudinal steel bars in a reinforced concrete beam is to overcome the weakness of concrete in tension.

True

(T/F): The stress-strain diagram of mild steel is nearly a straight line up to the yield point.

True