Structural Systems

Question 1

What are 3 grades of wood?

Answer 1

Stud grades - for studs, including load bearing
#1 structural framing - for headers and long spans
Utility grade - for blocking, etc

Question 2

What is glue laminated wood?

Answer 2

layers of dimensional lumber bonded together with durable, moisture-resistant structural adhesives so that all of the grain runs parallel to the longitudinal axis

Question 3

What is cross-laminated timber?

Answer 3

several layers of kiln-dried lumber boards stacked in alternating directions, bonded with structural adhesives, and pressed to form a solid, straight, rectangular panel

Lightweight yet very strong, with superior acoustic, fire, seismic and thermal performance, CLT is also fast and easy to install, generating almost no waste onsite.

Question 4

What is laminated strand lumber?

Answer 4

dried and graded wood veneers, strands or flakes that are layered upon one another and bonded together with a moisture-resistant adhesive into large blocks known as billets

(longer strands) not super strong, inexpensive

Question 5

What is oriented strand lumber?

Answer 5

OSL is made from flaked wood strands that have a length-to-thickness ratio of approximately 75. The wood strands used in OSL are shorter than those in LSL. Unlike OSB, the strands in OSL are arranged parallel to the longitudinal axis of the member

Question 6

What is parallel strand lumber?

Answer 6

Dried and graded wood strands are layered upon one another and bonded together with a moisture-resistant adhesive into large blocks known as billets
In the case of PSL, long strands (longer than those used in LSL) are laid lengthwise in parallel.

strong, heavy, relatively expensive

Question 7

What are wood i-joists?

Answer 7

dimensional lumber with an OSL board in between, used in floors, roofs, etc

Question 8

What is laminated veneer lumber?

Answer 8

an engineered wood product that uses multiple layers of thin wood assembled with adhesives
like plywood but thicker

Question 9

What are wood plastic composites?

Answer 9

weather resistant, less likely to shrink and warp more flexible

Question 10

What is oriented strand board? What is it used for?

Answer 10

strongest & stiffest of nonveneered panels
most common in subfloors and exterior sheathing

Question 11

What is fiberboard?

Answer 11

made from the smallest grain of wood (compared to OSB and particleboard)
best for interior uses
smoothest surface

Question 12

What are the plywood bond classifications?

Answer 12

Exterior - for exterior use
Exposure 1 - can handle some water, etc, but not meant to be exposed to weather long term (95% of plywood)

Question 13

What is a rim board or band joist

Answer 13

Sits on top of the header or floor below or foundation

Seals the open ends o the joists
provides surface for attachment of exterior insulation, cladding, and finish elements

Transfers some of the loads to the floor below

After the attic, this is the most likely place for insulation gaps & air infiltration

Question 14

Which is stronger, cold rolled or hot rolled steel?

Answer 14

Cold rolled steel is stronger than mild steel

Question 15

depth to span ratio: beam

Answer 15

Beam depth is generally 1/20 the span, width is ⅓ the depth

Question 16

depth to span ratio: girder

Answer 16

Girder depth is 1/15 the span, width is ⅓ the depth

Question 17

depth to span ratio: open web

Answer 17

Open web is 1/20 the span
Roofs, lightly loaded floors, or closely spaced can be 1/24 the span

Question 18

depth to span ratio: steel decking

Answer 18

Steel decking depth is 1/40 the span

Question 19

depth to span ratio: triangular steel truss

Answer 19

Triangular steel truss depth is ¼ the span

Question 20

depth to span ratio: rectangular steel truss

Answer 20

Rectangular truss depth is ⅛ the span

Question 21

What is the rebar naming convention?

Answer 21

Rebar # refers to the 1/8ths of an inch in diameter
Ex. #8 rebar is 8/8” or 1” diameter

Question 22

What are the rebar grades?

Answer 22

Grade 60 = 60k PSI, most common
Also comes in 40 & 75, use 75 for columns

Question 23

What is the correct amount for rebar overlap?

Answer 23

Overlap rebar at the ends by 30x the diameter or use reinforcing bar couplers

Question 24

What is prestressed concrete?

Answer 24

is substantially “prestressed” (compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service. This compression is produced by the tensioning of high-strength “tendons” located within or adjacent to the concrete

Pre-tensioned - mostly precast concrete

Post-tensioned - mostly cast in place

Question 25

What are the steps to pouring a slab on grade concrete pad?

Answer 25

1. Scrape topsoil off to reveal a more stable subsoil. if the subsoil is not stable you need to truck some in
2. At least 4” inches of 1.5” crushed stone to make a capillary break. roll out plastic sheet for moisture barrier
3. Formwork. Edge of metal or wood supported by in-ground stakes
4. Welded wire reinforcing on chairs or bolsters, or concrete brick to prevent rust moving through
5. Pour the slab
6. Scree the slab to make level
7. Keep damp for atleast a week
   8.Control joints every 15’

Question 26

concrete beam depth & width ratio

Answer 26

Width = 3 x height

Question 27

one way slab depth

Answer 27

4” - 20” deep, 1/22 the span, post tensioned 1/40 the span

Question 28

two way slab depth

Answer 28

5” - 12” deep, 1/30 the span, 1/45 if post tensioned

Question 29

drop panels depth

Answer 29

⅓ the span, ½ slab depth

Question 30

waffle slab depth

Answer 30

3” - 4.5” (plus depth of dome/pan), 1/24 the span, 1/35 if post tension

Question 31

concrete beams depth

Answer 31

1/16 the span, 1/24 if posttension

Question 32

concrete girders depth

Answer 32

1/12 the span, 1/20 if posttension

Question 33

What is pre-tensioned pre-cast concrete?

Answer 33

compressive stresses induced by high-strength steel tendons in a concrete member before loads are applied will balance the tensile stresses imposed in the member during service

Question 34

What is the modulus of rupture?

Answer 34

most important for determining a stones ability to accept metal anchor that hold them to buildings

Question 35

What is flexural strength?

Answer 35

most important for stone’s resistance to wind

Question 36

What are the most common CMU dimensions?

Answer 36

8 x 8 x 16 or 7 ⅝” x 7 ⅝” x 15 ⅝”

Question 37

How do you avoid water penetration in masonry?

Answer 37

Double wythe concrete block with capillary break
Finished with stucco, special paints, or special coatings that provide water resistance
Made with water repellent concrete and water repellent mortar
Use in arid climates

Question 38

what will determine the diameter of a long skinny column?

Answer 38

For long and skinny columns that are not placed far apart, the diameter of the column will likely be controlled by buckling rather than the load from above

Question 39

What is a theoretical k value?

Answer 39

higher k, more likely to buckle
Multiply by column length
Works for steel or concrete, recommended design k value is for wood

Question 40

What is shear a function of?

Answer 40

length squared

Question 41

what is deflection a function of?

Answer 41

length cubed

Question 42

what typically controls beam size?

Answer 42

bending moment

Question 43

between shear walls, braced frame, and moment resisting frame - what is most and least expensive?

Answer 43

shear wall - least expensive
moment resisting frame - most expensive (because you have to put extra bolts on each connection)

Question 44

what is the bending moment formula?

Answer 44

M(max bending moment) = (w (load per ft) x L^2)/8

Question 45

what is the max bending stress formula?

Answer 45

Fb = M (max bending moment in-lbs)/S (section modulus in^3)