Formwork for foundation walls Flashcards
Considering cost durability and reuse the most commonly used sheathing material used for formwork is
Plywood
List three categories in which items required for formwork system can be itemized
Plywood structural members, additional accessories, backer, form, tie hardware
Braces for formwork are most effective, if they are placed at an angle of ___, to ___ the horizontal
45° to 60°
Considering the formwork must eventually be dismantled give three things to consider when using nails
The number of nails, the nail type, duplex, adequate length and thickness for max holding power
List six items that may be used to give more rigidity and help align panels for wall forming systems
Studs plates, wailers, strong backs, kick plates braces
List three items to consider when selecting form ties
Compatible with the type of wailers used correct length for the thickness of the wall
Why are vinyl water stops serrated
It prevents the water from seeping around the stop
When would dumbbell shaped water stops be adequate for use in concrete joints
We’re a little to no Shear movement is expected
Rough box should be made at least ___ mm narrower than the concrete wall thickness
2-3mm
When should the centre bulb water stop be used in concrete joints
Where Shear Movement is expected.
What is the proper method of splicing PVC water stops on the job
Straight square cuts
Why must the centre bulb of the water stop be centred on the joint?
To allow movement
Why are keyways usually tapered rather than square or rectangular?
To be easily removed from the concrete
Describe how to form a control joint in the foundation wall
By attaching a bevelled strip of wood sheet metal, rubber, or plastic to the sheathing of the wall form
Crack control joints are required in concrete foundation walls if they exceed ___ in length
25
What is the combined thickness of the two strips used to form for a control joint in relation to the wall sickness?
1/4-1/5 the wall thickness
What is a construction joint?
Used when there is a stoppage in a poor and continues later
What is a control joint?
Used when there is a weakening of the concrete wall or slab in order to control. We’re cracking will take place.
What is an isolation joint?
Used as separation of the concrete from objects that may be damaged behaving or expansion of the concrete
After concrete forms have been dismantled, there are four areas of maintenance that must be considered. What are they?
Cleaning, repairing and oiling handling and storage hardware maintenance
Why should forms be cleaned of concrete immediately after dismantling?
The sooner cleaned the easier to do less damage is caused, and where to the forms
Why should a wire brush not be used to clean plywood forms?
It will loosen fibres on the form face
What should be done with split or cracked material
Get rid of it
For transporting forms and storage stack the forms
Face to face and back to back
Why are ties with plastic cones sometimes used?
Set a wall dimension and cover the plywood hole after the hole is stripped the cone and tie removed
What is meant by the break back on snap ties?
I want Hearne device to break after use
Why can ties rated at different strengths in the same wall cause a blowout?
It causes a momentary rise and pressure and weekends
What is the rate of poor, also known as the rate of placement?
The distance, the concrete rises in the form in one hour
While placing concrete in wall forms on a warm day, the pressure on the forms would___ faster compared to place in Concord on a cooler day
Decrease faster
Impact on concrete forms may be caused by vibration, and
Dropping from to high
