Chapter 12 - Structural Systems

Question 1

Most newer construction are of _______ construction

Answer 1

post and beam

Question 2

What can post and beam structures be made of?

Answer 2

Steel, concrete, or timber columns (posts) supporting a grid of beams on which the flooring is applied

Question 3

4 types of structural systems:

Answer 3

1. Steel
2. Concrete
3. Masonry
4. Load bearing walls

Question 4

Two most common steel structural systems

Answer 4

1. beam-and-girder
2. open-web joist

Question 5

In the beam-and-girder system, large members, called _______, span between columns and smaller _____ are framed into them. The ______ span shorter distances because they carry the weight of the _____.

Answer 5

girders beams
girders beams

Question 6

Typical spans for beam and girder system

Answer 6

25 to 40 feet

Question 7

What happens on top of the beam and girder steel framing?

Answer 7

covered with steel decking, which spans between the beams. concrete topping is poured over the decking

Question 8

Where is beam-and-girder most commonly used?

Answer 8

mid to high-rise office buildings

Question 9

What is a downfall of beam and girder system?

Answer 9

limited space between the bottom of the girder and the suspended ceiling. adding ductwork or recessed light fixtures should be reviewed

Question 10

In a ________ system, joists span between beams or bearing walls

Answer 10

open-web steel joist

Question 11

Open-web steel joist system can span

Answer 11

20 to 144’

Question 12

what goes on top of a the beam-and-girder system?

Answer 12

steel decking spans between joists and a concrete slab is poured on top of the decking

Question 13

Where do you see open-web steel joists?

Answer 13

one-story or low-rise buildings with wide column spacing

Question 14

what’s an upside of open-web steel joists?

Answer 14

mechanical and electrical service ducts, pipes, and conduit can easily be run between the web members. suspended ceilings and other lightweight interior elements can also easily b hung from the bottom of the joists

Question 15

Two main types of concrete structural systems

Answer 15

Cast-in-place and precast

Question 16

What is cast-in-place concrete?

Answer 16

concrete is poured into forms where it hardens before the forms are made

Question 17

What is precast concrete?

Answer 17

components are usually formed in a plant and shipped to the job site, where they are set in place and rigidly connected to form the structure

Question 18

Most cast-in-place concrete systems utilize only mild steel reinforcing set in the formwork before the concrete is placed. However, sometimes concrete is ________

Answer 18

post-tensioned

Question 19

What is post-tensioned?

Answer 19

steel cables within the concrete are tightened after the concrete sets, creating extra compression forces in the beam or slab

Question 20

If a slab is post-tensioned, what can you not do?

Answer 20

penetrate the slab for pipes or conduit

Question 21

Five basic types of cast-in-place concrete systems

Answer 21

1. beam-and-girder
2. concrete joist
3. flat plate
4. flat slab
5. waffle slab

Question 22

Beam-and-girder

Answer 22

similar to the steel system. slab is poured with the beams

Question 23

Concrete joist system

Answer 23

concrete members spaced 24 or 36 inches apart. because the joists are close together, it is more difficult to drill holes for small pipes and conduit

Question 24

flat plate construction

Answer 24

floor slab is designed and reinforced to transfer loads directly to the columns which generally do not exceed 25’ spacing used when floor to floor height must be kept to a minimum difficult to drill these types of floors because of closely spaced reinforcing

Question 25

Flat slab construction

Answer 25

similar to flat plate except drop panels (increased slab thickness around columns) are used to increase strength

Question 26

waffle slab system

Answer 26

(two-way joist system) can provide support for heavier loads at slightly longer spans. often left exposed and lighting is integrated into the coffers.

Question 27

Three types of pre-cast concrete floors

Answer 27

1. single tee 2. double tee 3. hollow-core slab

Question 28

advantage of single and double tee?

Answer 28

easy and fast to erect single and double team members simultaneously serve as beam AND floor decking

Question 29

\_\_\_\_ is generally limited to load bearing walls

Answer 29

masonry

Question 30

Because masonry is so expensive, it is usually used as \_\_\_\_\_\_\_

Answer 30

a veneer over wood stud walls or over concrete block walls

Question 31

Concrete block is the common term for \_\_\_\_\_\_

Answer 31

concrete masonry unit (CMU)

Question 32

Most common CMU size?

Answer 32

8"x8"x16" nominal (actual dimensions are 3/8" less than nominal to count for mortar)

Question 33

A load bearing wall may be \_\_\_,\_\_\_,or\_\_\_\_

Answer 33

concrete, masonry, or wood framing

Question 34

Load bearing walls are used more in commercial or residential?

Answer 34

residential

Question 35

Load bearing walls in commercial construction are normally where?

Answer 35

the core

Question 36

Load bearing walls in residential construction are normally where?

Answer 36

exterior, especially under eaves of the roof

Question 37

If you need to cut into a load bearing wall for something like a door, what needs to be done?

Answer 37

a double header or lintel needs to be added at the top of the opening

Question 38

A ________ is a force acting on a building element

Answer 38

building load

Question 39

Three major load types:

Answer 39

gravity, lateral, and dynamic

Question 40

What are gravity loads?

Answer 40

dead loads and live loads

Question 41

Examples of dead loads

Answer 41

columns, beams, exterior and interior walls, floor, chandelier, and mechanical equipment

Question 42

only time interior designer needs to consult structural regarding dead loads is

Answer 42

if unusually heaving partitioning (like masonry walls) or heavy equipment is being added

Question 43

live loads include

Answer 43

the weight of people, furniture, and other movable equipment

Question 44

lateral loads include

Answer 44

wind loads and earthquake loads

Question 45

if a building is in a high-risk area for earthquakes, certain interior elements need to be detailed to resist earthquake forces. examples include

Answer 45

partitions that are tied to the ceiling, suspended ceilings, ductwork, lights, sprinklers, bookcases, storage cabinets, lab equipment, and access floor

Question 46

when a force is applied suddenly, it's called an \_\_\_\_\_

Answer 46

impact load

Question 47

when a load is applied suddenly or changes rapidly, it is called a \_\_\_\_\_\_\_\_

Answer 47

dynamic load

Question 48

examples of dynamic loads

Answer 48

cars moving in a parking garage, elevators traveling in a shaft, or a helicopter landing on a building

Question 49

Interior partitions in commercial construction that attach to the structural floors above or the perimeter of the building, should be designed with \_\_\_\_\_\_\_

Answer 49

slip joints to allow the building to move without putting pressure on the partitions

Question 50

Large building movements are accommodated by \_\_\_\_\_\_

Answer 50

expansion joints

Question 51

2 rules for expansion joints

Answer 51

1. don't put partitions over them 2. don't cover them up with finish materials

Question 52

Easiest cast-in-place concrete to penetrate with a core drill?

Answer 52

beam-and-girder and one-way pan joists

Question 53

One of the most common types of floor and roof construction?

Answer 53

concrete on metal deck

Question 54

Can you do core drills in concrete on metal deck?

Answer 54

yes

Question 55

Actual size of 2x4 wood studs?

Answer 55

1.5" x 3.5"

Question 56

\_\_\_\_\_\_\_\_ are horizontal repetitive members used to support the floor

Answer 56

joists

Question 57

The space between joists is spanned with ______ or ______ 5/8" or 3/4" sub-flooring

Answer 57

plywood or particleboard sub flooring in prep for the finish flooring

Question 58

\_\_\_\_\_\_ is nailed to the outside of the stud wall to stiffen the wall and provide a nailing base for the exterior finish material

Answer 58

sheating

Question 59

When openings for doors and windows are framed in wood construction, they are framed at the top with \_\_\_\_\_\_

Answer 59

lintels (also called headers)

Question 60

Standard sizes for window and door headers?

Answer 60

double 2x4 , 2x6, or 2x8

Question 61

For two-story wood construction, _____ framing is used

Answer 61

platform framing

Question 62

Platform framing uses

Answer 62

wood studs on a sole plate and a double top plate at the ceiling level

Question 63

If stronger members than 2x4s or 2x6s are needed, ______ can be used

Answer 63

glue-laminated wood members or glulams

Question 64

What are glulams?

Answer 64

built up from a number of individual pieces of lumber, which are glued together and finished under factory conditions for use as beams, columns, purlins, and other structural components think covenant

Question 65

when are glulams used?

Answer 65

heavy load/long spans unusual structural shapes are required and appearance is a consideration

Question 66

What is a cricket?

Answer 66

saddle-shaped projection on a sloping roof used to divert water around an obstacle

Question 67

The amount of slope of a roof is designated by its \_\_\_\_\_\_

Answer 67

pitch

Question 68

roof pitches are in \_\_\_\_\_" increments

Answer 68

12 inches example: 5/12 pitch 5" of rise for every 12" of horizontal projection

Question 69

a machine used to cut a small opening in a concrete floor for conduit or poke-through electrical outlets

Answer 69

core drill

Question 70

in a high-rise building, the wall generally used as part of the stucture of the building and surrounding the common building services, such as elevator and stairway shafts, toilet rooms, mechanical rooms, and the like

Answer 70

core wall

Question 71

a stud above a door opening or below a windowsill

Answer 71

cripple stud

Question 72

light-gage sheets of steel that are ribbed, fluted, or otherwise stiffened by the shape for use in constructing a floor or roof

Answer 72

decking

Question 73

a mixture of portland cement, water, and sand containing enough water to allow it to be poured or pumped into joints, spaces, and cracks within masonry walls

Answer 73

grout

Question 74

a framing member that crosses and supports the ends of joists, transferring the weight of the joist to parallel joists. these are used to form openings in wood-framed floors

Answer 74

header

Question 75

a horizontal structural member over an opening that carries the weight of the wall above it

Answer 75

lintel

Question 76

a piece of timber laid horizontally

Answer 76

purlin

Question 77

the plywood or particleboard covering placed over exterior studding or rafters of a building that provides strength and a base for the application of wall or roof cladding

Answer 77

sheathing

Question 78

a horizontal wood member that serves as the base for the studs in a stud partition

Answer 78

sole plate

Question 79

a wood member in a floor or roof used to support a header

Answer 79

trimmer

Question 80

a structural beam of steel having a shape whose cross section resembles the letter H. A ____ beam has wider flanges than an I-beam. These are used for beams as well as columns because their shape gives them approximately equal strength in both direction

Answer 80

wide-flange beam