G4 Flashcards
on which kind of surface should slab on grade be placed
sub grade or existing soil should be of suitable bearing or compacted fill
What factors affect the durability of slab on grade
protection from weather, water/ cement ratio or finishing
what factors affect the strength of slab on grade?
base material concrete mix, curing
What should be done to walls or columns that pass through or beside slab on grade?
provide isolation joints
why is it important t to compact the sub grade
give firm even bearing
why are screeds and forms oiled before oiled before before concrete placement?
easy cleaning
how long should slab forms remain in place in place after concrete placement ?
As long as possible
What is the difference between a flat plate slab and a flat slab
flat plate has a plain soffit, flat slab will have a drop panel or column capital
What advantage do column capitals give
increased shear strength and reduces strength span of load
What direction does load carrying steel span?
perpendicular to beams
dome pans are used in which type of slab
two way (waffle slabs)
what’s a spandrel beam
It’s located at perimeter of slab
how does a two way joist system differ from a single joist system
two way runs in two directions, one way runs in one
in what sequence does does stripping usually take place
beams sides then soffit
What is the first step in setting a beam form
place the beam bottoms on the shore system
why does a spandrel beam require a wider shore head than other beams beams or girders or the same width?
to provide space for walking
where do beam sided usually sit
on the shore head
how are wooden t-shores set to elevation
wedges
how are forms for drop panels supported
shores stringers and joists
What is the slenderness ratio
1:50 typical ratio of minimum ratio thickness of post to unsupported height
describe three ways shores are made adjustable
screw jack, wood wedges, Ellis clamp
why are re shores not fitted tightly to the concrete that they are supporting
so they won’t place undue pressures on the concrete while reshoring
describe a slab table
truss shoring, stringer joists, plywood deck, screw jack
What are flying forms?
fly tables or gang forms
how are aluma beams attached to false work
slotted bottle and bolt
what’s a mudsill used for
to distribute the weight
using a slender ratio of 1:50 what’s the maximum unsupported height of a rough 4x4 wooden shore
16’ 8”( (4x50) / 12 )
What are void forms used for ?
reduce volume, weight and cost
What type of slab formwork uses dome form panels?
2 way
how is ribbed slab formed
using long pans
What is a OWSJ?
open web steel joint
when would a FRP be used in constructing forms
architechtural finishes
why should a waffle slab be used
strength, looks, and lightweighted
What would be a typical spacing for concrete joists ?
600-800mm o.c
how are slab tables constructed
19mm ply attached to nailer strips in aluminum joists joists are attached to trusses using clips the truss has adjustable support legs
how are adjustable legs used
fine tuning fold away for flying
How are odd spacers formed
infill panels and backer rod
who’s responsible for the design of the form work
professional engineer
when is the first pair of cables attached when relocating slab tables
after the tables been rolled out & the first 2 lifting points are exposed
list 4 ways to make the flying of the slab tables more efficient
Mark the location of shoring, Mark height on supports jacks, match sling ends with lifting points
at what wind speed must the job site be shut down
over 100km/h 60mph
if a member of the lifting found a more efficient method of lifting the slab tables what need to be done n before implementing the idea
approval of engineer
list the info found on the erection drawings relating to the reshoring of suspended concrete structure
reshore plan, strength of concrete, size, spacing order or reshore
explain the process that is used to cycle the formwork and re shores for a multi story building
form, shore , pour , cure, strip, reshore,
how should reshore be placed when there are point loads above them
directly under point load, also to support slab
how should re shores be placed when there are no point loads above them
to support slab and beams, in rows to be braced
list two types of reshoring systems
post & scaffold
