J1 - Seismic Flashcards
Load path?
Provide a continuous transfer of loads to the foundation
Liquefaction?
When soil acts like a liquid
Tying footings to the foundation wall and anchor bolts?
Rebar & dowels
when rods used to provide a continuous tie from the top of the building to the foundation?
Couplers are used to join the sections
Wall to floor system strap
Tie upper wall to the lower wall to the floor system
Drag strut?
maintain horizontal load, connects a beam or truss to the top plate
completes the load path and allows loads to be transferred out of the roof or floor sheathing into the wall system where the shear walls are.
Lateral force?
Force imposed on a building by an earthquake, moves the building sideways
How must a building be constructed to withstand seismic events?
That the studs work togehter, along wit the sheathing
Inertia?
As the foundation can move, the upper part of the building may remain static,
the heavier the building, the the inertia
building drift?
side to-side movement of a building in relation to its stationary foundation
How do you build to reduce drift?
reduce the percentage of drift with greater stiffness
Ductility?
Ability which a material can bend or twist without breaking
wood frame is more ductile than concrete
Liquefaction?
Soil acts like a liquid.
Proximity to a fault line?
Closer building is to a fault line, the more severe the force of an earthquake will be
Weight limitations?
Heavier the building, the greater the stresse
wood frame construction is lighter wiehfght and has a high weight to strength ratio
An ideal house?
A simple rectangle, braced bearing walls directly above and below each floor, evenly and symmetrically distributed throughout and increasing in length in the lower floors.
What results in disproportionate loading?
Unbalanced loading (floors that are heavier than others)
Exterior veneers:
Add more weight
Reduce ductility of a wall making it more susceptible to failure
stucco lath surrounds entire structure and helps
Braced wall band:
imaginary continuous straight band extending vertically and horizontally through the building or part of the building, within which braced wall panels are constructed
Foundation attachment:
Each wall-braced wall panel must have at least: two anchor bolts where two or more floors are supported by a foundation and the SA(0.2) is greater than 0.7
Floor system attachment
Boxing rim joist that uspport braced wall panels need to be toenailed to the plates they rest on with 3 1/4” nails at 6 oc
Support of walls for fastening:
Load bearing & non-load-bearing walls braced wall panels must be blocked under or otherwise supported to allow their bottom plates to be fastened down with 3 1/4 nails at 6
Wall Sheathing attachment:
Braced wall panels require 63mm (2.5” nails instead of minimum 51 mm (2”) if lumber sheathing is used, it must be installed diagonally across the studs
Roof sheathing:
Acts as a diaphragm, must have full panel type or diagonally applied
Requires 2 1/2” nails instead of min 2”
Floor systems:
decrease on centre spacing and increase size to increaxe overall structural integrity
primary lateral load transfer in floor system through boxing joist
On wall bearing walls to fully transfer load
Use full depth blocking beneath
How can you improve floor’s lateral resistance?
Increasing the floor sheathing thickness
