Deck 26: Masonry and Concrete Bearing Wall Construction

Question 1

the keyway between precast- concrete hollow- core slabs is generally

A)reinforced with horizontal steel dowels.
B)grouted.
C)reinforced with T- shaped steel dowels.
D)A and C.
E)A and B.

Answer 1

E

Question 2

The commonly used floor system in high- rise and mid- rise masonry bearing wall buildings in North America is

A)cast- in- place reinforced- concrete slabs.
B)precast- concrete double- tee units.
C)precast- concrete hollow- core slabs.
D)all of the above.
E)none of the above.

Answer 2

C

Question 3

A cellular- type floor plan in a multistory building is generally inherent in the following occupancies:

A)Mercantile occupancies
B)Educational occupancies
C)Residential occupancies
D)Business occupancies
E)None of the above

Answer 3

C

Question 4

Masonry walls without joint reinforcement are called plain- masonry walls.

Question 5

In a cross- bearing wall structure, the load- bearing walls are

A)perpendicular to the main axis of the building.
B)parallel to the main axis of the building.
C)A or B.
D)A and B.

Question 6

A load- bearing wall structure works best when the floor plan of the building has

A)walls that are continuous up from the foundations.
B)walls that are distributed almost uniformly in both principal directions.
C)walls at an upper floor that align with the walls at a lower floor.
D)all of the above.

Question 7

A bond beam in a masonry bearing wall building must be

A)a steel, reinforced- concrete, reinforced- masonry, or wood beam.
B)a steel or reinforced- concrete beam.
C)a reinforced- concrete or reinforced- masonry beam.
D)a steel, reinforced- concrete, or reinforced- masonry beam.
E)none of the above.

Question 8

A bond beam in a masonry bearing wall building

A)is preferably used along the shorter span.
B)is embedded in the walls.
C)may be used along the shorter or longer span.
D)is preferably used along the longer span.
E)none of the above.

Question 9

Historical load- bearing masonry structures were designed with the assumption that

A)all wind loads on the building were resisted by exterior walls only, and in doing so, they interacted with each other structurally.
B)interior and exterior walls and floor and roof diaphragms resisted wind loads collectively.
C)all wind loads on the building were resisted by exterior walls only, with no structural interaction between them.
D)both interior and exterior walls resisted wind loads.
E)none of the above.

Question 10

In high- rise residential buildings built with site- cast reinforced- concrete bearing walls using tunnel forms, the floors and roofs are generally constructed of

A)precast- concrete hollow- core slabs.
B)wide- flange steel beams and metal deck.
C)steel joists and metal deck.
D)lumber joists and beams.
E)none of the above.

Question 11

Where the cutting of masonry units is discouraged, the wall dimensions are based on the masonry module. The module used in CMU walls is

A)12 in.
B)4 in.
C)8 in.
D)16 in.
E)none of the above.

Question 12

Compared to a longitudinal- bearing wall floor plan, a cross- bearing wall floor plan generally gives larger exterior wall openings.

Question 13

A bond beam in a masonry bearing wall building is required for structural reasons

A)at each floor level.
B)at each floor level and roof level.
C)at each floor level, roof level, and top of the parapet.
D)above all openings in exterior walls.
E)none of the above.

Question 14

the keyway between precast- concrete hollow- core slabs runs perpendicular to the bearing walls.

Question 15

The formwork used in constructing site- cast reinforced- concrete walls and floors simultaneously consists of

A)sheet steel tunnel forms.
B)insulating concrete forms.
C)sheet steel gang forms.
D)horizontal and vertical plywood forms.
E)none of the above.

Question 16

A typical bond beam is provided with

A)stirrups.
B)horizontal reinforcement.
C)horizontal reinforcement and stirrups.
D)none of the above.

Question 17

Referring to a masonry wall as a reinforced- masonry wall implies that the wall contains

A)vertical reinforcing bars.
B)horizontal reinforcing bars.
C)bond beams.
D)joint reinforcement.
E)none of the above.

Question 18

The structural behavior of a contemporary load- bearing masonry wall building is similar to that of

A)a site- cast reinforced- concrete frame building.
B)a precast- concrete frame building.
C)a steel- frame building.
D)a conventional wood light- frame building.
E)none of the above.

Question 19

Use of the load- bearing masonry wall system became extinct for a while and was revived

A)around the mid- nineteenth century.
B)around the early nineteenth century.
C)after World War II.
D)around the late nineteenth century.
E)after World War I.

Question 20

The clear height of openings in CMU walls is

A)3/8 in. greater than the multiples of the masonry unit module.
B)1/8 in. less than the multiples of the masonry unit module.
C)1/8 in. greater than the multiples of the masonry unit module.
D)3/8 in. less than the multiples of the masonry unit module.
E)none of the above.

Question 21

To provide continuous insulation in a tilt- up wall building, the choice generally is the use of

A)sandwich tilt- up wall panels.
B)EIFS cladding on wall panels.
C)masonry veneer cladding with rigid insulation between panels and cladding.
D)A or B.
E)B or C.

Question 22

The design of contemporary load- bearing masonry structures is based on the structural interaction between various elements of the building (walls, floors and roof)in resisting the lateral loads. On what basis were the traditional (historic)load- bearing masonry structures designed?

Question 23

The concrete tilt- up wall construction system is generally used in

A)mid- rise buildings-5 to 15 stories.
B)low- rise buildings-1 to 4 stories.
C)high- rise buildings-20 stories or more.
D)all of the above, depending on the local expertise and economy.

Question 24

The most commonly used strength of concrete for tilt- up wall panels is

A)6,000 psi.
B)5,000 psi.
C)4,000 psi.
D)3,000 psi.
E)2,000 psi.

Question 25

What are the bond beams in masonry walls constructed of?

Question 26

The adjacent corner tilt- up wall panels should be connected together in all situations.

Question 27

Insulating concrete forms can only be used for

A)exterior load- bearing walls more than 10 in. thick.
B)interior or exterior non- load- bearing walls.
C)interior load- bearing walls.
D)all of the above.
E)none of the above.

Question 28

The pipe braces that support concrete tilt- up walls are typically removed when

A)all wall panels have been erected, anchored to the footings, and the floor and roof structures have been completed.
B)all walls panels have been erected and anchored to the footings.
C)all wall panels have been erected, anchored to the footings, the floor and roof structures have been completed, and the exterior finish to wall panels has been applied.
D)all wall panels have been erected.
E)all wall panels have been erected, anchored to the footings, and the floor structures have been completed.

Question 29

In a tilt- up wall construction system, the walls are

A)precast in a plant and transported to the construction site for erection.
B)precast at the construction site.
C)cast in place at the construction site.
D)B or C, whichever is more economical.

Question 30

In a sandwich tilt- up wall panel, the structural wythe of concrete is on the exterior face of the wall.

Question 31

The adjacent noncorner tilt- up wall panels

A)are connected using 6 in. × 6 in. steel plates at 6 ft on center.
B)should not be connected unless the building is located in a seismic or high- wind region.
C)should not be connected unless the building is located in a seismic region.
D)are connected using a continuous steel plate extending from the bottom of the panel to its top.

Question 32

The most commonly used exterior finish on tilt- up wall panels is

A)Portland cement stucco.
B)adhered masonry veneer.
C)EIFS.
D)paint.
E)anchored masonry veneer.

Question 33

The foundations for concrete tilt- up walls consist of

A)drilled pier footings.
B)isolated pad footings.
C)continuous strip footings.
D)any one of the above.
E)none of the above.

Question 34

Reinforced- concrete tilt- up walls are generally used as

A)load- bearing enclosure walls whereas the interior structure consists of a precast- concrete frame.
B)load- bearing enclosure walls whereas the interior structure consists of a cast- in- place reinforced- concrete frame.
C)load- bearing enclosure walls whereas the interior structure consists of a structural steel frame.
D)non- load- bearing enclosure walls whereas the entire structure consists of a structural steel frame.
E)any one of the above.

Question 35

The most commonly used method of connecting tilt- up walls to the slab- on- ground is

A)a continuous steel angle welded to panels and the slab- on- ground.
B)a continuous concrete closure strip in the slab- on- ground.
C)individual steel plates welded to panels and the slab- on- ground.
D)A or C.
E)B or C.

Question 36

The most commonly used strength of concrete for the slab- on- ground in concrete tilt- up wall buildings is

A)6,000 psi.
B)5,000 psi.
C)4,000 psi.
D)3,000 psi.
E)2,000 psi.

Question 37

What is the function of bond beams in load- bearing masonry walls?

Question 38

What is the role of vertical reinforcement in masonry walls?

Question 39

During the erection of concrete tilt- up wall panels, a gap is left between the bottom of a panel and the top of the footing. This gap is approximately

A)1 in. to 2 in.
B)2 in. to 3 in.
C)1/2 in. to 1 in.
D)none of the above.

Question 40

In which locations are bond beams needed in load- bearing masonry walls?

Question 41

The tunnel- form construction is limited in applicability to certain building types. Which are these types?

Question 42

The tilt- up wall construction uses load- bearing reinforced concrete walls. Are the tilt- up walls used only for the building exterior or are they used for both interior and exterior walls of the building?

Question 43

The dimensions of length and width of wall segments and the openings in walls in load- bearing masonry wall structures should be multiples of a module to avoid frequent cutting of masonry units. What is the size of the module for CMU walls?

Question 44

Bond beams in load- bearing masonry walls are constructed of either masonry bond beam units or as reinforced concrete beams. What is (are)the advantage(s)of using reinforced concrete bond beams?

Question 45

Bond beams in load- bearing masonry walls are constructed of either masonry bond beam units or as reinforced concrete beams. Why is the use of masonry bond beam units preferred for their construction?

Question 46

Why do multistory, load- bearing wall buildings have a cellular type structure?

Question 47

Explain why the typical thickness of tilt- up wall panels is one of the following dimensions: 5- 1/4 in., 7- 1/4 in., or 9- 1/4 in.

Question 48

Two types of floor plans are possible in multistory, load- bearing wall structures: (i)cross- bearing wall plans and (ii)longitudinal- bearing wall plans. Which of these two is more amenable to providing large openings in exterior walls and which one gives large interior open spaces?

Question 49

Does the reinforced concrete tilt- up wall construction compete with load- bearing masonry wall construction or the reinforced concrete tunnel- form construction?

Question 50

In a tilt- up wall building, the wall panels are precast at site. Explain the type of formwork used for casting of the walls.

Question 51

Does tunnel- form construction yield a load- bearing reinforced concrete wall structure or a load- bearing reinforced masonry wall structure or a reinforced concrete column- and- beam (frame)structure?

Question 52

To avoid cutting of CMUs, the dimensions of CMU wall segments and the openings in walls are multiples of an 8- in. module. What is the relationship between the dimension of an opening in a CMU wall as the multiple of an 8- in. module and the actual dimension of the opening?

Question 53

Which of the two masonry materials-CMU or clay bricks-is commonly used in load- bearing walls and why?

Question 54

Which types of occupancies are best suited for load- bearing wall buildings?

Question 55

Name single- story occupancies for which load- bearing masonry walls are commonly used.

Question 56

How long after placing concrete in them are the tunnel forms typically removed?

Question 57

To avoid cutting of CMUs, the dimensions of CMU wall segments and the openings in walls are multiples of an 8- in. module. What is the relationship between the dimension of a CMU wall segment based on the multiple of an 8- in. module and the actual dimension of the wall segment?

Question 58

In terms of their structural behavior, what is the essential difference between:
(i)load- bearing reinforced masonry wall structures with precast hollow core slabs and (ii)site- cast reinforced concrete load- bearing wall structure with site- cast reinforced concrete slabs?

Question 59

In tunnel- form construction, the walls are constructed of site- cast reinforced concrete. What are the floors and roof constructed of?

Question 60

In tunnel- form construction, is the formwork for vertical elements (walls)and horizontal elements (floors and roof)made of: (i)one component or (ii)two separate components?

Question 61

What is the commonly used strength of concrete in tilt- up wall panels?

Question 62

In a tilt- up wall building, the wall panels are precast on a concrete slab- on- ground, which is the first floor slab of the building. In some buildings, the first floor of the building is not a concrete slab- on- ground but an elevated slab. Explain how the tilt- up walls are cast in this type of building.

Question 63

List the various load- bearing wall systems described in this chapter.

Question 64

What kind of connection is provided between adjacent tilt- up wall panels?

Question 65

With the help of a sketch and notes, explain what a closure strip is with respect to a tilt- up wall building.

Question 66

With the help of sketches and notes, explain why the walls in a traditional masonry- bearing wall structure had to be extremely thick.

Question 67

Explain why tilt- up wall panel- to- panel connections are discouraged and why they are necessary for corner panels. In which situations are panel- to- panel connections required?

Question 68

Explain why the live load on the slab- on- ground in a concrete tilt- up wall building is generally higher during the construction of the building than in- service live load.

Question 69

After the tilt- up wall panels are lifted off the casting bed and brought into their final locations using a crane, they are plumbed vertical and provided with temporary supports. What do the temporary supports consist of?

Question 70

Explain the importance of vertical reinforcement in load- bearing masonry walls.

Question 71

What are form liners, as used for casting of tilt- up wall panels?

Question 72

What is the purpose of a closure strip in tilt- up wall buildings?

Question 73

The thickness of tilt- up wall panels is obviously related to the magnitude of stresses caused in them due to the loads on the panels. Two types of stresses are caused in panels: (i)the stresses caused by gravity loads and lateral loads after the building has been constructed, i.e., in- service loads and (ii)stresses caused during the lifting and erection of panels. Which of these two stresses determines the panel thickness and why?

Question 74

What is the purpose of bond beams, and where are they required in a typical load- bearing masonry structure?

Question 75

An opening in a tilt- up wall panel represents area of weakness during lifting and erecting operation, particularly if the opening extends close to the panel end. What measure is taken to ensure that such a panel does not crack or is otherwise damaged during lifting and erection?

Question 76

With the help of sketches and notes, explain why it is desirable to reinforce the ends, corners, and jambs around openings in the walls of load- bearing masonry buildings.

Question 77

In a tilt- up wall building with a large footprint, the exterior walls are constructed of concrete tilt- up wall panels. What does the interior structure of the building consist of?

Question 78

With the help of a sketch, explain what the tunnel form is, and describe its benefits and limitations.

Question 79

What is the typical exterior wall finish provided on tilt- up wall buildings?

Question 80

What is the maximum size of a tilt- up wall panel based on?