G8 - Specialized Concrete Formwork - Tilt-up construction

Question 1

Explain tilt up-construction

Answer 1

1) Panel cast on slab, cured to design strength
2) Tilted up and braced
3) Crane next
4) Lace the braces and weld the panel connection

Question 2

Why is the floor slab required to be very strong?

Answer 2

To support the weight of 1) Crane 2) Panels

Question 3

Why should the floor slab be very flat?

Answer 3

Smoother wall finish

Question 4

List four types of buildings that are built using tilt-up construction:

Answer 4

Warehouse, office, institutional and residential.

Question 5

Where is “infill” concrete placed?`

Answer 5

At the base of a wall.

Question 6

Describe the formwork that is used for tilt-up wall panels.

Answer 6

Wood or metal forms.

Question 7

How are newly erected tilt-up panels usually held in position?

Answer 7

Metal bracing

Question 8

What is the purpose of the grout pads?

Answer 8

Leveling panels

Question 9

Describe how the base of the tilt-up wall panels is held in place:

Answer 9

Infill concrete and dowels.

Question 10

List two differences between a normal floor slab and a floor slab for a tilt-up building:

Answer 10

Tilt-up is level, smoother, and stronger.

Question 11

Which surface of the finished wall will have the lifting inserts exposed?

Answer 11

Inside

Question 12

What is a rebound hammer?

Answer 12

Engineer tool for concrete strength.

Question 13

Describe what is covered in the pre-lift safety meeting.

Answer 13

The responsibility of each person, where to not stand, signal person, and rigging safety checklist.

Question 14

Describe the lifting of a wall panel:

Answer 14

1) Check wind
2) Clear workers
3) Outriggers extended and blocked

Question 15

When are pilasters used to join wall panels?

Answer 15

To support concentrated loads.

Question 16

What holds the wall panels permanently in place at the top of the wall panel?

Answer 16

Welded or bolted to steel ledger.

Question 17

What are the wall braces connected to on the wall panels?

Answer 17

Inserts .

Question 18

Temporary bracing for tilt-up construction must not be removed until:

Answer 18

Inspected by a building design engineer he/she has written a statement that the bracing is no longer needed.

Question 19

Tilt-up panels must reach what strength before lifting?

Answer 19

Required strength specified by the engineer.

Question 20

Crane must hold panel until:

Answer 20

Steel braces are bolted into place.

Question 21

Once braces are installed on tilt-up panels, then:

Answer 21

Crane can release the panel and pick up another.

Question 22

Panels are bolted together with:

Answer 22

A steel angle iron is also used as a ledger to support the roof trusses.

Question 23

Footings for a tilt-up panel:

Answer 23

Cast on undisturbed soil at an elevation that will put the bottom of the tilt-up wall panel below the elevation of the floor slab by at least 12”

Question 24

Rebar is cast in an L shape into the bottom of the wall panel for what purpose:

Answer 24

To connect the infill concrete to the wall panel

Question 25

What are grout pads set for on each footing?

Answer 25

To allow the elevation to be exactly controlled.

Question 26

After the panels are in their final location: The footing is covered with?

Answer 26

A mound of fresh concrete to keep the panels from moving during the backfilling of the infill area.

Question 27

The floor slab is kept back from the perimeter of the building by approximately 4-6 feet:

Answer 27

This allows working room around the footings supporting the tilt-up wall panels.

Question 28

How best to stack panels?

Answer 28

To reduce movement of crane, stack panels

Panels with openings should be at the top or openings are filled with formply, to support the next panel.

Question 29

What is usually required around lifting inserts?

Answer 29

Extra re-bar

Question 30

Bracing inserts must be located where?

Answer 30

Find them in the brace inserts as seen in panel shop drawings.

Question 31

How is concrete placed in tilt-up construction?

Answer 31

Accelerator is used in the mix to speed the strength gain and allow lifting of the panels to begin soon after placing concrete.

Question 32

Which side of the tilt-up panel is the finished side?

Answer 32

The bottom side (slab must be clean and free from oil and other debris.

Question 33

Inside of building in tilt up panel is covered with:

Answer 33

Insulation and wall finish.

Question 34

Site engineer uses what test to determine the concrete strength?

Answer 34

Will use a rebound hammer to determine the actual strength of the concrete for each panel.

Amount that the hammer rebounds indicates the strength, stronger the concrete, the more it rebounds.

Question 35

How are wall braces installed in tilt-up construction?

Answer 35

Extend from the supporting slab to near the top, secured with bolt. bottom plate is installed square to the wall

Supported near their midpoint by knee braces

Question 36

How are braces connected together?

Answer 36

With cross-lacing at mid-point Attached to the braces with brackets.

Question 37

Openings in tilt up panels are supported how?

Answer 37

Strongbacks are added to panels with openings in them to support the narrow pieces during lift process.

Question 38

Most rigging systems for tilt-up involve what components?

Answer 38

Spreader bar is equipped with pulleys that allow the sling lengths to self-adjust as the panel is tilted up from the floor slab.

Question 39

What is used to support roof trusses?

Answer 39

A steel ledger bolted at the top of the wall panels.

Question 40

Roof construction provides what stability?

Answer 40

A huge diaphragm (Horizontal shear surface) that braces all of the walls together.

Question 41

Top of the walls are finished with?

Answer 41

Cap flashing, the flashing continues into the roof deck.

Question 42

Pilaster forms:

Answer 42

Support vertical loads of overhead beams. Pilasters are formed using pilaster clamps.