Deck 9: Principles of Joints and Sealants Expansion and Contraction Control

Question 1

Which of the following joint sealants has the highest movement ability?

A)Acrylic
B)Polyisobutylene
C)Silicone
D)Polyurethane

Answer 1

C

Question 2

A building separation joint in a multistory building generally

A)runs through all floors, the roof, and the foundation.
B)runs through all floors.
C)runs through all floors and the roof.
D)runs through all floors and the foundation.
E)runs through alternate floors, the roof, and the foundation.

Answer 2

C

Question 3

Building separation joints in a long rectilinear building are generally located at every

A)400 ft on center.
B)250 ft on center.
C)500 ft on center.
D)350 ft on center.
E)none of the above.

Answer 3

B

Question 4

The unit of measure for the coefficient of moisture expansion (/x)is

A)°C- 1 or °F- 1.
B)°C or °F.
C)feet or meters.
D)watts.
E)none of the above.

Question 5

A spandrel beam in a building is a beam that

A)is partially embedded in the ground.
B)is supported by a continuous wall below it.
C)supports a continuous wall above it.
D)has a floor slab or roof slab on both sides.
E)runs on the outside edge of a floor or roof.

Question 6

Which of the following materials is subjected to moisture movement?

A)Concrete
B)Brick
C)Wood
D)All of the above
E)Only A and B

Question 7

The equation used for determining the thermal movement, t, of a member is

A)6t = L(Ot).
B)6t = αL(Ot).
C)6t = [L(Ot)]/α.
D)6t = (αL)/(Ot).
E)6t = [α(Ot)]/L.

Question 8

Which of the following materials has irreversible moisture expansion during service, that is, after construction?

A)Concrete
B)Brick
C)Natural stone
D)Steel
E)Aluminum

Question 9

A seismic joint is generally similar to a building expansion joint but smaller in width.

Question 10

In determining the total width of a movement joint between building components, we account for the dimensional and construction tolerances. Poor or inadequate quality control on a construction site

A)increases dimensional tolerances.
B)increases construction tolerances.
C)decreases dimensional tolerances.
D)decreases construction tolerances.
E)none of the above.

Question 11

The unit of measure for the coefficient of thermal expansion (a)is

A)°C or °F.
B)°C- 1 or °F- 1.
C)feet or meters.
D)watts or joules.
E)none of the above.

Question 12

Creep deformation is caused by

A)wind loads.
B)dead loads.
C)live loads.
D)all of the above.
E)none of the above.

Question 13

A joint between two walls has been determined to be 0.5 in. if the joint is not to be filled with a sealant. If the same joint is to be filled with a class 50 sealant, its width should be

A)1/4 in. maximum.
B)1/4 in. minimum.
C)2- 1/2 in. minimum.
D)1 in. minimum.
E)none of the above.

Question 14

Which of the following materials has the highest coefficient of thermal expansion?

A)Aluminum
B)Glass
C)Plastics
D)Steel
E)Concrete

Question 15

Creep deformation occurs in

A)aluminum members.
B)concrete members.
C)steel members.
D)all of the above.

Question 16

The sealant in a joint works best when it is subjected to

A)tension, compression, shear, and bending.
B)tension or shear only.
C)tension, compression, and shear.
D)tension or compression only.

Question 17

The width of a building separation joint is generally

A)2- 1/2 in. to 3 in.
B)4- 1/2 in. to 5 in.
C)1- 1/2 in. to 2 in.
D)3- 1/2 in. to 4 in.
E)1/2 in. to 1 in.

Question 18

A non- load- bearing wall that runs under a spandrel beam should be adequately separated from the beam to allow the beam to move freely in the

A)horizontal direction.
B)vertical direction.
C)both A and B.

Question 19

Which of the following joint sealants has the highest abrasion resistance?

A)Polyurethane
B)Polyisobutylene
C)Acrylic
D)Silicone

Question 20

Which of the following materials does not represent a joint sealant?

A)Silicone
B)Polysulfide
C)Polyvinyl chloride
D)Polyisobutylene

Question 21

What is the value of the maximum annual temperature change used in the text in determining the maximum annual thermal expansion or contraction of a component?

Question 22

What is a control joint and how does it differ from an expansion joint?

Question 23

In determining the amount of thermal expansion or contraction of a component due to temperature change, check below the factor(s)that are not relevant.
1. Change in temperature of component
2. Compressive strength of the component's material
3. Tensile strength of the component's material
4. Original length of material
5. Coefficient of thermal expansion

Question 24

What is the purpose of a separation joint?

Question 25

Joints in building components are divided into three subtypes. Name them.

Question 26

What is elastic deformation?

Question 27

A movement joint allows stress- free expansion and contraction of buildings and components while a static joint subjects the building and components to movement stresses. So, why are movement stresses undesirable?

Question 28

In which structural materials does creep take place and in which it does not?

Question 29

Do metals (such as steel and aluminum)expand or contract greater than plastics, such as (polyethylene and nylon)when subjected to the same temperature change?

Question 30

What is creep?

Question 31

Movement joints are divided into two types: (i)building joints and (ii)component joints. Building joints are further subdivided into two types. Name them.

Question 32

What is the typical width of a building separation joint?

Question 33

If a rectangular building's dimension is large in both directions, can we have a separation joint (SJ)in both directions so that the building has two separation joints crossing each other at right angle? How many structurally independent buildings will such a design create?

Question 34

Because the provision of static joints adds to the stresses on a component, requiring a larger cross section, which increases the cost of the component, should the static joints be avoided? Explain.

Question 35

When the live load acts on a floor slab and the floor deflects downward, is the deflection in the slab an elastic or inelastic deflection?

Question 36

Does every building require separation joint(s)? Explain.

Question 37

Which structural materials (i)undergo moisture shrinkage only (no moisture expansion)during service, and which materials (ii)undergo both moisture expansion and shrinkage during service?

Question 38

There are two types of joints in buildings: static joints (non- movement joints)and dynamic joints (movement joints). What is the advantage of movement joints over static joints?

Question 39

A rectangular building with a large footprint in both directions has been provided with one separation joint (SJ)in each direction so that the SJs cross each other at right angle. The building is a frame structure, consisting of columns and beams and it has been decided to duplicate the columns and beams at the joint. How many columns will be needed at the location where the joints cross?

Question 40

Which structural materials (i)undergo both thermal expansion and thermal contraction during service, and which materials (ii)undergo only moisture expansion (no moisture shrinkage)during service?

Question 41

For a brick masonry fence wall (a wall between residential neighborhood and the street), the width of the joints between masonry wall panels has been determined as 1 in. Should the wall be provided with backer rod and sealant and the width of the joint increased? Explain your answer.

Question 42

Explain the differences between a seismic joint and a building separation joint.

Question 43

Explain the relative suitability of a static joint versus a dynamic (movement)joint in buildings.

Question 44

Explain why a low- modulus sealant is generally preferred over a high- modulus sealant.

Question 45

Using sketches and notes, explain the various types of movement joints used in buildings.

Question 46

Discuss the benefits of tooling a joint sealant.

Question 47

What is creep, and how does it affect the movement of building components? Explain.

Question 48

What is a spandrel beam?

Question 49

Which exterior- use sealant has the highest movement capability and which sealant has the highest abrasion resistance?

Question 50

Which sealant is commonly used as caulk for interior applications?

Question 51

Silicone, polyurethane, and polysulfide are commonly used as joint sealants. Explain their relative suitability for various applications.

Question 52

Why should a joint sealant have adhesion only to the two opposite surfaces of a joint? Explain.

Question 53

With the help of a sketch, explain why and where building separation joints should be provided.

Question 54

Should a clear space be provided between a floor slab (or a roof slab)and a partition wall below? Explain your answer.