G5 - Describe Embedded Materials Flashcards
What is a concrete formwork dowel and what is it used for?
Dowel - Short piece of rebar
Uses: Connect two separate cast-in-place concrete sections
How are anchor bolts placed when great accuracy is not needed?
Inserted into concrete after placement but before concrete sets.
What material is used to make most bolt templates?
19 MM lumber or plywood
Why is it not good practice to wiggle anchor bolts to achieve consolidation? What should be done instead?
Wiggling to achieve consolidation should be avoided - this tends to consolidate with concrete paste only and will not give a good holding power.
Consolidate by tapping around the bolt on the formwork itself
Describe how to make an expansion joint in a slab:
1) Smooth dowel embedded in 1st slab
2) Pour 1st
3) Strip
4) Fiber board
5) Grease dowel use expansion cap and pour 2nd
What is used to fasten pre-cast concrete members together?
Welding
List two types of inserts -
T-bar and Loop
Which kind of reglet requires no caulkng:
PVC
What materials are manufactured reglets made from?
PVC or Metal
How are sewer access covers held in place during concrete placement?
By own weight
Why are trough forms held down with a ballast?
To keep from floating
How are trough forms held in position during concrete placement?
Ballast, supported on bricks and ties down or staked.
What are sewer access covers and rates usually made from?
Cast iron
What material is used to shim manhole covers in elevation
Metal shims
What are the two methods of installing dock levelers?
Cast in place or pit mounted
What can be done to support forms from floating as the concrete is being placed around them?
1) Ballast
2) Stakes and bracing
How are the forms held in place horizontally?
Attached to rebar, braces & stakes
What is used to support the end of the conduit at the dock leveler?
Template
List four things to check prior to placing concrete:
Control conduits, elevations of top of formwork, level & square.
List two types of waterstops:
Serrated and plain
What pressures at waterstops designed to resist:
Hydrostatic
What type of constructions are waterstops used?
Hydraulic structure, sewage treatment and water tanks.
List three properties that all waterstops must have:
1) Flexible
2) Continuous
3) Watertight seal
What is the widest water stop that can be used for a wall that is 300 mm thick?
300 MM WIDE
Anchor bolts provide what sort of support?
Lateral support transfer from floor system to foundation wall
What is a method to accommodate error for an anchor bolt install?
Pipe sleeves, they can be adjusted by being slightly bent
What must be done to all anchor bolts prior to pour?
Protect threads from splatter, wrap with tape or coat with grease
Dowels are made from what kind of rebar?
Dowel made from deformed or smooth steel bars
If dowel penetrates soil, what will happen?
Dowel will rust
Dowels must penetrate how far in each concrete section if not specified?
24 times diameter of dowel
Deformed bars are often used in what applications?
Keyway forms, to secure stair, porch or cantilever supports
Deformed bars have what sort of ridge?
Lug like ridges, this allows them to interlock with concrete.
Rebar sizing for imperial:
10 bar - 10/8
Concrete must be set back a minimum:
Cast against and in contact with ground: 3”
Exposed to weather: 1.5 to 2”
Not exposed to weather or in contact with ground: 3/4 to 1.5”
Lapping bars should overlapped how much:
24 times bar diameter
Lapping bar vertically should be lapped how much?
10 bar diameters for vertical
Bending can be done for bars up to what size?
up to 15 on site
What is the purpose of an expansion joint?
Uses smooth dowel to keep two slabs in alignment - Dowel hold both slabs in place while smooth surfaces allows the slab to move horizontally
Misc metals must be installed:
-Accurately,
-Securely so they don’t move
-Not interfering with formwork
Embedded metals are anchored to concrete metals how?
Deformed rods, bolts or bent bars.
How are handrails attached in concrete stairways?
Welded plates
How is T bar ceiling hanger installed in a concrete suspended slab?
Laid out, then pounded into slab form
What is a reglet?
A continuous groove that is cut or formed into a wall. Usually above the point of intersection with a flat roof.
How is counter flashing installed?
Counter flashing is installed by caulking or grouting into the reglet (counter-flashing is placed so that it slows down, directing water away from the joint between wall and roof)
A Reglet is usually how deep?
25 mm deep
How do you form reglets?
Wooden strip is nailed to the form, leaving groove when the formwork is dismantled.
Prefab metal strip already filled with caulking, which remains in place after form is removed.
How are troughs formed into cocnrete?
Using block outs, provide a lip to support grate or drain trough covers.
What is a grate?
Cast iron metal component installed in a floor to allow water to flow into the drain.
What is a dock leveler?
Adjustable deck installed on loading docks used to give level access to the back of freight.
Formwork for pit-mounted dock levelers :
Box that is sent into the surface of a concrete slab, it will be encased with concrete on 5 sides.
When is a dumbell waterstop used?
When there is significant expansions and contraction expected. Bulb at the centre is able to shift and move with concrete movement.
When is a serrated water stop used?
Where differential settlement is expected and a firm grip in the concrete is required.
What is a caulk grade water stop?
Caulk-type waterstop that does not have to be secured to the form as the concrete is poured. Instead it is applied over a construction joint with caulking gun.
