PX- Chapter 12: Structural Systems

Question 1

what type of construction are most new buildings? Not material but way of building

Answer 1

post and beam

Question 2

name and describe two steel structural systems

Answer 2

1. beam-and-girder: girders are like large beams that span between the columns, then beams connect the girders. girder spans are shorter than beams because they carry heavier loads. Usually used in mid to high rise office buildings. Usually limited space between the bottom of the girders and the suspended ceiling which makes it harder to install ductwork or recessed light fixtures. beams are spaced around 8-10ft.
2. Open Web steel joist system: joists span between beams or load bearing walls. 2-6 feet spacing. One story or low rise buildings with wide column spacing. because the webs are open it’s easier to put ducts and wiring through them

Question 3

name and briefly describe two common concrete structural systems .

Answer 3

1. Cast in place: concrete poured in to forms on site. Uses mild steel reinforcing in the concrete (easier to poke holes through)
2. Precast: components pre-cast in the factory and brought to site. Use steel cables in the casting process.

Question 4

Name and describe 5 types of cast-in-place concrete building systems

Answer 4

1. beam-and-girder: looks like columns with beams going out in all 4 directions from the columns. slab is integrated with these beams & girders.
2. Concrete joist system: far space columns with 4 beams connecting them, then “joists” running in one direction from one side to another. joists are so close together it can be hard to drill even small holes for pipes and conduit.
3. Flat Plate construction: four columns and a floor. the floor slab transfers all of the load directly on to the columns which are usually spaced 25’ apart or smaller. Needs a lot of reinforcing so hard to drill holes as well. Also used with lower ceiling heights
4. Flat Slab construction- like flat plate, but with extra support at the column tops
5. Waffle slab system- better for heavier loads and slightly longer spans

Question 5

what is a load bearing wall (or bearing wall) and it’s properties

Answer 5

support loads from above. all loads- live and dead loads. cannot be removed but can have doors or windows in them with appropriate beams or lintels.

Question 6

name and describe three major types of building loads

Answer 6

1. Gravity loads- include dead loads and live loads- done by architect
2. Lateral Loads- wind loads and earthquake loads- done by architect
3. Dynamic Loads- when a force is applied suddenly it’s an impact load. when it changes suddenly it’s a dynamic load. like cars driving in to a garage or helicopter

Question 7

what is a dead load

Answer 7

vertical loads due to the weight of the building and any permanent equipment- includes things like columns, beams, exterior and interior walls, floors, chandeliers and mechanical equipment

Question 8

what is a live load

Answer 8

weight of people or furniture and other removable equipment

Question 9

what types of cast in place construction would best be suited to small floor penetrations for pipes and conduits and why.

Answer 9

beam and girder system, one way pan joist because there is less reinforcing used in these systems

Question 10

what type of concrete building system would be best suited to large floor penetrations and why

Answer 10

flat plate and flat slab because holes cant be cut near or where the columns are or where the beams are. But additional structural support is required obviously

Question 11

in residential construction, what is a lintel

Answer 11

when doors or windows are required, the top will have extra framing called a lintel or header with additional 2x4 (double stud)

Question 12

what type of beam would you use if you wanted to span a longer span than typical joists allow

Answer 12

joists typically allow for 20’ span, so use a glue lam beam, an I-shaped joist or a laminated veneer lumber beam

Question 13

how are roofs classified

Answer 13

by their shape

Question 14

what do you need on a roof when something vertical penetrates the roof?

Answer 14

a cricket- it keeps water from collecting between the roof and the vertical element at the top part. kind of a triangle sticking up off the roof.

Question 15

what is a roof pitch

Answer 15

the slope of the roof which is the number of inches of rise for every foot of horizontal projection

Question 16

name and describe 4 roof types

Answer 16

1. Shed- half a roof like a horse shed
2. gable- typical house shaped
3. Hip- a gable but the front and back bits slope inwards towards the center of the house
4. gambrel- shaped like a barn

Question 17

what are some questions interior designers should be able to answer about structural items

Answer 17

• is this item structural?
• if yes, can I modify it in any way?
• can floor penetrations be made?
  is building movement expected? If yes, how can it be accommodated
• is a structural review necessary for the proposed new floor loading?
• how should new interior construction elements interface with existing structural elements?