G2 - LT #1 Factors of affected form Flashcards
List the 5 main factors that affect form design:
1) Safety
2) Architectural design
3) Types of concrete members being cast
4) Efficiency
5) Environmental conditions
What special design considerations must be made for wall forms:
Wall form design depends on the form system and desired rate of placement.
What special design considerations must be made for suspended slab designs:
Suspended slab design depends mainly on the slab form.
What special design considerations must be made for pre-cast concrete design?
Depends on multiple uses and high temperature curing.
What are two factors that affect pressure on the formwork?
1) Rate of placement 2) Rate of concrete setting
How does the air temperature affect the rate of placement?
Direct proportions - air temperature increases, so can placement rate and when air temperature decreases, so should the placement rate.
What type of admixtures will increase the slump of the concrete?
Plasticizers
What type of formwork is used in dam construction:
Cantilevered construction
Architectural concrete allows for a deflection of:
1/400,
Narrow stud spacing and low rate of place for concrete is required.
What is the most important aspect of slab on grade concrete?
Sub grade for slab must be very well compacted, made from materials that drain very well.
What is a footing?
Form is usually a simple ladder constructed of 2x10 with cleats 24” to 32” o.c
To create a smooth, nice finished above grade wall, what is required?
Rate of placement slow, stud spacing will have to be slow.
Main concern with Falswork is:
The falsework being used to support slab
Main concern with Pre-cast
Being able to withstand hundreds of re-uses, sometimes up to 3 times a day.
What is the rate of placement?
Rate of placement - height of concrete that is placed in one hour
A tall structure has a lot of pressure where?
The bottom area
Slump is measurement of:
Consistency
Concrete made with low water/cement ratio and no admixtures to increase the slump will have:
A low slump
Fluid (very liquid9) concrete created by plasticizer will produce a pressure, similar to fully vibrating the form what is needed?
Needs to be accounted for in the formwork design.
Where should the end pump be when placing in concrete?
End of the pump hose should be positioned as close to the level of the previously placed concrete as possible.
If the concrete is allowed to fall through rebar:
Cement paste sticks to the rebar and large aggregate falls to the bottom, creating honey combing
When placing concrete with a crane and bucket, what care should be taken?
Do not overload the forms by placing it in one spot.
