Question 1

In what order are the following steps typically undertaken in the iterative process of designing a singly reinforced concrete beam?
1. Determine dimensions of beam cross-sections
2. Specify an assumed concrete compression strength and steel reinforcement tensile strength
3. Calculate areas of steel required, select steel dimension, and calculate compression block area
4. Calculate nominal moment strength and verify it is greater than the ultimate moment strength
5. Analyze the beam loading
6. Repeat steps if needed (increase concrete strength, steel tensile strength and/or beam cross-sectional area)

A)1, 2, 3, 4, 5, 6
B)2, 3, 5, 6, 1, 4
C)3, 4, 1, 5, 2, 6
D)5, 2, 1, 3, 4, 6

5, 2, 1, 3, 4, 6

Accepted Answer

The order of the steps typically undertaken in the iterative process of designing a singly reinforced concrete beam is as follows:
• Analyze the beam loading
• Specify an assumed concrete compression strength and steel reinforcement tensile strength
• Determine dimensions of beam cross-sections
• Calculate areas of steel required, select steel dimension, and calculate compression block area
• Calculate nominal moment strength and verify it is greater than the ultimate moment strength
• Repeat steps if needed (increase concrete strength, steel tensile strength and/or beam cross-sectional area)
The design of a singly reinforced concrete beam is based on ensuring the required strength of the beam (ultimate moment strength) is exceeded by the nominal moment strength multiplied by a strength reduction (safety) factor.

Question 2

Which of the following internal stresses develop in a beam that is supporting a load?
1. Normal
2. Abnormal
3. Bending
4. Moment
5. Shearing

A)1, 2, 3
B)1, 3, 4
C)1, 2, 5
D)1, 3, 5

1, 3, 5

Accepted Answer

A beam that is supporting a load develops the following internal stresses: normal, bending, and shearing. Beams are structural members that can carry loads. Internal stresses develop from the geometrical loads that are mostly perpendicular to the beam's longitudinal axis.

Question 3

Which of the following is not considered a mode of failure in beams?&#10;A)Torsion&#10;B)Vertical shear&#10;C)Horizontal shear&#10;D)Bending

Accepted Answer

Torsion is not considered a common mode of failure in beams. The two most common types of beam failure modes are bending and horizontal shear. Vertical shear is most often encountered in short beams. Another type of beam failure mode is associated with excessive deflection.

Question 4

Which of the following concrete slab design methods is included in the American Concrete Institute's publication 318-11: Building Code Requirements for Structure Concrete and Commentary?&#10;A)Direct Design Method (DDM)&#10;B)Equivalent Frame Method (EFM)&#10;C)A. and B.&#10;D)None of the above

Accepted Answer

The concrete slab design methods included in the American Concrete Institute's publication 318-11: Building Code Requirements for Structure Concrete are the DDM and EFM. The DDM is used to design slab systems that have at least three spans in each direction and are subject to only gravity loads. The EFM is used to design slab systems with irregular layouts, if the slab will be subject to horizontal or partial loading patterns, and/or if the live load to dead load ratio applied to the slab is high.

Question 5

In what order are the following steps typically undertaken in the iterative process of designing a singly reinforced concrete beam?
1. Determine dimensions of beam cross-sections
2. Specify an assumed concrete compression strength and steel reinforcement tensile strength
3. Calculate areas of steel required, select steel dimension, and calculate compression block area
4. Calculate nominal moment strength and verify it is greater than the ultimate moment strength
5. Analyze the beam loading
6. Repeat steps if needed (increase concrete strength, steel tensile strength and/or beam cross-sectional area)

A)1, 2, 3, 4, 5, 6
B)2, 3, 5, 6, 1, 4
C)3, 4, 1, 5, 2, 6
D)5, 2, 1, 3, 4, 6

5, 2, 1, 3, 4, 6

Accepted Answer

The order of the steps typically undertaken when designing a two-way concrete slab system using the DDM is as follows:
• Determine slab thickness
• Divide slab into frames and calculate total design moment
• Distribute moments throughout slab
• Determine steel requirement
• Select and distribute reinforcing bars
• Design required beams
The DDM can be used to design slab systems that contain at least three spans in each direction that are loaded by gravity loads (with or without beams).

Question 6

Which of the following factors is used to determine the minimum thickness of a concrete floor slab?&#10;A)Deflection control&#10;B)Shear strength (beamless slabs)&#10;C)Flexural moment requirements&#10;D)All of the above

Accepted Answer

The factors used to determine the minimum thickness of a concrete floor slab include: deflection control, shear strength (beamless slabs), and flexural moments requirements. Because slab weight is an important component of the dead load, the slab thickness is one of the first things determined in the design process.

Question 7

When following the Direct Design Method (DDM) to design a concrete slab, the reinforcement size and spacing are selected based on crack control requirements, bar lengths, and which of the following?&#10;A)Stresses due to shrinkage and temperature&#10;B)Soil strength&#10;C)Moment-shear transfer&#10;D)All of the above

Accepted Answer

When following the DDM to design a concrete slab, the reinforcement size and spacing are selected based on crack control requirements, bar lengths, and stresses due to shrinkage and temperature. The moment-shear transfer is addressed by slab thickness, not reinforcing bars. Soil strength is evaluated prior to selecting a slab system as the foundation for the supported structure.

Question 8

When designing a reinforced concrete footing, which of the following requirements does not typically have to be met?&#10;A)Calculated bearing pressure < allowable bearing pressure&#10;B)Calculated settlement < allowable settlement&#10;C)Calculated vertical load < total overturning moment&#10;D)None of the above

Accepted Answer

When designing a reinforced concrete footing, the requirement "calculated vertical load < total overturning moment" typically does not have to be met. Vertical loads include the loads applied to the foundation, the weight of the foundation itself, and the weight of the soil above the footing. Lateral loads and/or overturning moments such as wind loads or seismic activity may also influence a footing. In cases where footing may be subject to these types of eccentric loads, a method for calculating non-uniform bearing pressure can be used.

Question 9

Which of the following publications provides the building code requirements for reinforced concrete footings?&#10;A)American Concrete Institute (ACI) 318-11&#10;B)ASTM International 318-11&#10;C)American Society of Civil Engineers (ASCE) 318-11&#10;D)None of the above

Accepted Answer

The American Concrete Institute publication 318-11 provides the building code requirements for reinforced concrete footings. The ACI publication, entitled 318-11: Building Code Requirements for Structure Concrete and Commentary," includes requirements for the materials, design, construction, quality assurance and testing methods for structural concrete building components. Additionally, the publication includes methods to evaluate the strength of existing concrete structures.

Question 10

In what order are the following steps typically undertaken in the iterative process of designing a singly reinforced concrete beam?
1. Determine dimensions of beam cross-sections
2. Specify an assumed concrete compression strength and steel reinforcement tensile strength
3. Calculate areas of steel required, select steel dimension, and calculate compression block area
4. Calculate nominal moment strength and verify it is greater than the ultimate moment strength
5. Analyze the beam loading
6. Repeat steps if needed (increase concrete strength, steel tensile strength and/or beam cross-sectional area)

A)1, 2, 3, 4, 5, 6
B)2, 3, 5, 6, 1, 4
C)3, 4, 1, 5, 2, 6
D)5, 2, 1, 3, 4, 6

5, 2, 1, 3, 4, 6

Accepted Answer

The order of the steps typically undertaken when designing a reinforced concrete footing is as follows:
• Identify type and use of structure supported
• Determine foundation loading requirements
• Identify site soil characteristics and local conditions
• Select foundation geometry
• Complete the structural design (including reinforcing bars)
The design of reinforced concrete footings is based on the loading, footing properties and soil characteristics. Footing designs are checked to ensure compliance with the local building code, that the bearing pressures and settlement calculations are within allowable limits and the constructed foundations will have sufficient capacity and stability to resist sliding and overturning.

Deck 11: Member Design