Concrete

Question 1

When are slurry walls typically used in excavations?

Answer 1

When the excavation will be below the water table.

Question 2

What is a commonly used material to control water seepage in high water table excavations?

Answer 2

Steel-sheet piling.

Question 3

What should you do if water begins to accumulate in a trench where you are working?

Answer 3

Immediately get out of the trench.

Question 4

What does a building project’s stability depend upon?

Answer 4

The stability of the soil.

Question 5

How is the density and strength of soil improved in most construction projects?

Answer 5

Compaction.

Question 6

What is an effective tool for compacting soil in trenches?

Answer 6

Vibrating-plate compactor.

Question 7

What is the term for inclining the sides of a trench in steps to prevent cave-ins?

Answer 7

Benching.

Question 8

What is the single most important variable in soil compaction?

Answer 8

Moisture content.

Question 9

What are the multiple layers called when fill is placed and compacted?

Answer 9

Lifts.

Question 10

What is the water table?

Answer 10

The elevation at which groundwater is encountered.

Question 11

What technique is used to break up very large boulders?

Answer 11

Blockholing.

Question 12

When can wall panels cast on a floor slab be tilted up?

Answer 12

When they reach 75 percent of design strength.

Question 13

What is the typical thickness of slabs used as casting beds?

Answer 13

3-1/2 inches.

Question 14

What size boards are commonly used as edge forms for tilt-up panels?

Answer 14

2” × 6” or 2” x 8” lumber.

Question 15

How is smaller aggregate exposed after tilt-up?

Answer 15

Pressure washing.

Question 16

Why shouldn’t water be allowed to pond and freeze on a cast panel?

Answer 16

It would cause the surface to flake.

Question 17

What can skin exposure to concrete or mortar cause?

Answer 17

Cement dermatitis.

Question 18

During panel lifting and bracing, who is allowed in the lifting perimeter?

Answer 18

Only the erection team.

Question 19

Before tilting up a panel, what is installed?

Answer 19

Beam seats and shelf angles.

Question 20

Why should stringers be centered on U-heads and top plates?

Answer 20

To avoid eccentric loads.

Question 21

What are required characteristics of mudsills used to support shores?

Answer 21

They must be sound and rigid.

Question 22

Why must the shoring system be strong for one-way solid slabs?

Answer 22

Because of the massive weight of concrete being placed all at once.

Question 23

Who must design the shoring system?

Answer 23

A structural engineer.

Question 24

What do one-way solid slabs span between?

Answer 24

Beams or walls.

Question 25

What support do two-way beam-and-slab floors require?

Answer 25

Beams and walls.

Question 26

When are slurry walls typically used in excavations?

Answer 26

When they will become the structure's foundation walls

Question 27

To control water seepage in high water table excavations, what material is commonly used?

Answer 27

Steel-sheet piling

Question 28

What should you do if water begins to accumulate in a trench?

Answer 28

Immediately get out of the trench

Question 29

What is the most important variable in soil compaction?

Answer 29

Moisture content

Question 30

Fill is placed and compacted in multiple layers called?

Answer 30

Lifts

Question 31

What are the high-strength steel cables in post-tensioned concrete called?

Answer 31

Tendons

Question 32

What does the live load for shoring mostly consist of?

Answer 32

Workers and equipment

Question 33

What is the slab form in a composite slab?

Answer 33

Corrugated steel

Question 34

Two-way joist slabs are also known as?

Answer 34

Waffle slabs

Question 35

How are the ribs and slab of one-way joist slabs cast?

Answer 35

Monolithically

Question 36

What is used to expose smaller aggregate after tilt-up?

Answer 36

Pressure washing

Question 37

What happens if cast concrete panels freeze after water ponds on them?

Answer 37

The surface may flake

Question 38

Skin exposure to mortar can cause?

Answer 38

Cement dermatitis

Question 39

Wall panels cast on a slab can be tilted up at what strength?

Answer 39

75 percent of design strength

Question 40

Common board sizes for tilt-up edge forms?

Answer 40

2" x 6" or 2" x 8" lumber

Question 41

Final deck elevation adjustment is done using?

Answer 41

Haunches

Question 42

Support angles should not be welded to beams that?

Answer 42

Are in tension

Question 43

A steel deck surface in contact with concrete should be?

Answer 43

Phosphatized

Question 44

Slabs for casting beds typically have what thickness?

Answer 44

3-1/2 inches

Question 45

Joists in hand-set decks are normally?

Answer 45

Fabricated from aluminum

Question 46

To simplify form stripping, hand-set decks use?

Answer 46

Proprietary drop-heads

Question 47

Beam forms should use minimum plywood thickness of?

Answer 47

3/4"

Question 48

Mud sills are used when?

Answer 48

Slab-on-grade is not placed and cured

Question 49

Stringers should be centered to?

Answer 49

Avoid eccentric loads

Question 50

Mudsills must be sound and?

Answer 50

Rigid

Question 51

For heavy concrete loads, shoring must be?

Answer 51

Massive

Question 52

One-way solid slabs span support lines formed by?

Answer 52

Beams or walls

Question 53

Elevated slab construction mainly depends on?

Answer 53

Shoring and reshoring

Question 54

Mud sills support shores when?

Answer 54

Slab-on-grade not placed and cured

Question 55

Wood shores are adjusted using?

Answer 55

Removable jack wrench