J-1 Seismic

Question 1

force caused by earth quake

Answer 1

lateral (sidways)

Question 2

load path

Answer 2

provides a continuous transfer of loads to the foundation.

Question 3

Building drift

Answer 3

refers to the degree of lateral side to side movement of a building in relation to its stationary foundation
- greater %age of drift the greater building will suffer during earth quake
- building that is stiffer will reduce drift
-

Question 4

ductility

Answer 4

the extent at which a material can bend or twist without breaking

Question 5

soil conditions

Answer 5

understanding soil base under building is important

• areas that have high water tables can be susceptible to soil liquefaction where building sinks causing building to lean
• denser soils are more desirable

Question 6

proximity to fault line

Answer 6

closer structure is to fault line, the more severe the forces of an earth quake will be

Question 7

weight limitations

Answer 7

heavier the building, the greater the stress as result of an earthquake. relatively light weight wood frame buildings an successfully withstand some earthquakes because there strong and flexy

Question 8

building configurations

Answer 8

ideal house has as simple rectangular configuration with braced bearing walls directly above and below each floor.

Question 9

exterior vaneers

Answer 9

• brick add more weight to wall and reduce the ductility of wall making it more susceptible to failure
• stucco can help because of steel mesh surrounding wall

Question 10

building height

Answer 10

greater the building height the more susceptible to lateral loads. from both earth quakes and wind
- wood building can be no bigger then 6 stories

Question 11

Load Paths

Answer 11

building is made up of different building systems
- floor system
- wall system
- foundation
- roof
a building ability to resist earthquake loads are directly proportional to strength of individual systems and connections between them

Question 12

Braced wall band

Answer 12

imaginary continuous band extending vertically and horizontally through the building or part of the building.

Question 13

Foundation attachments

Answer 13

each braced wall panel must have at least two anchor bolts where two or more floors are supported by foundation. max spacing is 8’ for 5/8 bolts and 5’7 for half inch bolts.

one bolt must be 20” ffrom corners

Question 14

floor system attachments

Answer 14

boxing rim joist that support braced wall panels are toenailed to the plates they rest on with 3 1/4” nails every 6”

Question 15

Support of walls for fastening

Answer 15

Load bearing and non load bearing wall panels must be blocked under to allow bottom pates to be nailed every 6 “

Question 16

wall sheathing attachments

Answer 16

braced wall panels require 2 1/2” nails instead of 2”.

Question 17

Roof sheathings

Answer 17

must have full sheathing or diagonally applies lumber type roofing use 2 1/2” nails

Question 18

Primary lateral load transfer in floors

Answer 18

occurs through boxing joists

can also be transfered through parallel blocking between joists

gluing or increasing OC of nails will also make floor stiffer along with size of sheathing.

Question 19

walls most prone to failure

Answer 19

Pony walls at foundation level. because they are at the end of load paths.

• double top plate allows to tie into supporting floor systems
• individual blocking between each stud where it mets foundation is required. these increase walls resistance to lateral loads.
• studs should be doug fur or western pine.
• keep nails 3/4” away from edge of top plate.

Question 20

how to tie floor systems into wall systems together

Answer 20

hang sheeting long and wilt so it can be nailed into both floor systems and existing wall system

Question 21

what happens if you over drive a nail in sheathing

Answer 21

even 1/8th can reduce strength of wall by as much as 40-50%

Question 22

walls with large openings

Answer 22

walls like that have large openings like garage doors often require steel details to make up from lack of sheathing.

Question 23

Roof and ceiling

Answer 23

• transfer loads to walls supporting it. this connection is crucial
• ## clocking in ceiling joists and roofing members is good practice (toenailing piece we did with mark)

Question 24

foundation seismic hardware

Answer 24

concrete is much stronger in compression then tension so additional steel reinforcements in concrete footings and wells will increase ability to withstand these loads.

Question 25

L shaped rebar

Answer 25

L’s in the footing can tie footing into foundation wall. these steel bars can then be ties into anchor bolts from wall plates.

Question 26

Strap anchors

Answer 26

straps are embedded into concrete then nailed onto walls.

Question 27

Hold downs.

Answer 27

simpson HD19 hold downs is secured to concrete using anchor bolts then bolted to stud pack. threaded rod is then made to form continuos path through out building

Question 28

Floor systems joist hangers

Answer 28

various joist hangers are available to improve seismic resistance where floor members are joined.

Question 29

wall to floor strap connections

Answer 29

these connections can be reinforced with the use of straps. these straps should be used on inside and outside of walls.

Question 30

Drag struts

Answer 30

to connect a beam or truss to to top plate this completes load paths.

Question 31

Truss to plate connections

three functions of roof tie downs.

Answer 31

roof system seismic hardware is generally designed to perform three functions

1. resist rotational loads resulting from lateral forces
2. anchor roof system to wall
3. prevent uplift.