construction systems

Question 1

kinds of loads
(2 types) (6)

Answer 1

Vertical
* Dead Load (DL)
* Live Load (LL)
* Snow Load (SL)

& Lateral
* Wind Loads (WL)
* Earthquake Loads (EL)
* Special Loads (water, earth, traffic)

Question 2

principle forces that act on building elements (2 + 1)

Answer 2

compression + tension
shear

Question 3

basic structural requirements of load-bearing elements

Answer 3

• strength (ability to hold weight)
• rigidity
• geometric stability & resistance

Question 4

static equilibrium

Answer 4

also: mechanical equilibrium, newton’s third law of motion

sum of the forces acting on an object/structure is zero

Question 5

transfer of load through structures to the ground induces ____ in each loaded element

Answer 5

stress

Question 6

must stay consistent under loading (geometric stability)

Answer 6

angles between elements

Question 7

structural systems (5)
Engels classification, 1968

Answer 7

• Vector-active
• Section-active
• Surface-active
• Form-active

Question 8

vector-active structures
(Engels)

Answer 8

• solid, straight-line, often short elements
• small cross-section
• can only transmit/bear one force (compression vs. tension) in the direction of their length

flat, curved and spaced trusses

Question 9

section-active structures
(Engels)

Answer 9

• strength through cross-section + continuity of material

beam + beam grid, frames & horizontal/vertical slabs

Question 10

surface-active structures
(Engels)

Answer 10

• transmit all forces (compression, tension + shear) through surfaces

plate, folded plate & shell structures

Question 11

form-active structures
(Engels)

Answer 11

• stability created through form - often geometric stability
  arch, tent, cable, pneumatic

Question 12

sources of loads (3)

Answer 12

natural
useful
accidental

Question 13

natural structural loads

Answer 13

always:
* gravity
* self/dead
* wind

sometimes:
* earth/water pressure
* earthquakes
* temperature
* ground movement

Question 14

useful structural loads

Answer 14

related to the function of the structure
live loads

vary greatly depending on function - e.g. people, traffic, machinery, storage of materials

industrial processes may change ambient temperature - creates ‘useful’ temp loads

Question 15

accidental structural loads

Answer 15

often contingencies for safety purposes

if accidents are likely/unavoidable, structure should resist loads these accidents cause

Question 16

load cases

Answer 16

the combination + sum of different loads acting on a structure

the worst/maximum load case is often the most important