Structures

Question 1

strength of structure

Answer 1

• materials behavior
• the capacity of the structural system to withstand the load that is applied to it
• first function

Question 2

stability of structure

Answer 2

• equilibrium for all forces and moments
• the capacity of a structural system to transmit various loadings safely to the ground
• second function

Question 3

strength failure

Answer 3

if the legs of a chair cannot support the applied load they will fracture or break
- not bearing the load

Question 4

stability failure

Answer 4

the stability of the system of elements depends upon the orientation of the chair in space
if tilted, the structural system loses its equilibrium
- loss of equilibrium

Question 5

stability

Answer 5

structures may be in equilibrium but not stable
arrangement of parts critical
adding bracing will not make structure fall, such as internally bracing (high rise building )
and externally bracing (wide+low rise buildings like bridges)

Question 6

what is a load?

Answer 6

load is a force that acts on a structure.

2 types of loads - primary - secondary

Question 7

primary load

Answer 7

• primary load - dead load - self-weight of structure - fixed building elements like columns
• primary load - live load - occupancy (moving people) - environmental/ variable

Question 8

Secondary load

Answer 8

-secondary load- thermal
-secondary load - settlement
(accounts for secondary load only once)

Question 9

concentrated load vs distributed load

Answer 9

concentrated = example standing on a table 
distributed = example laying down on table

Question 10

principle of transmissibility

Answer 10

all loads are finally transmitted and resisted by the ground

Question 11

equilibrium

Answer 11

two types of equilibrium

• external = encompasses all loads and reactions of the structural system as a whole
• internal = encompasses all the forces within every member of the system

Question 12

parabolic curves

Answer 12

a curve genrated by evenly distributed load along a horizontal axis.
examples a suspension bridge

Question 13

catenary curve

Answer 13

a curve generated by evenly distributed loads (own weight) along the length of a curve.

Question 14

funicular curves

Answer 14

a curve generated by point loads distributed at various points (not evenly) along a curve
examples Gaudi’s hanging structures

Question 15

difference between tensions + compression

Answer 15

tension = force that pulls materials apart. force is exerted out
compression = force that squeezes materials together. force is exerted down

Question 16

resistance: BENDING

Answer 16

• lateral
• torsional
• vertical

Question 17

modes of failure

Answer 17

• steel bottim of concrete structure avoids tensions and cracking

Question 18

material behaviours

Answer 18

• stress
• strain
• elasticity - plasticity
• safety factors

Question 19

stress + strain

Answer 19

Force - causes - stress
stress - puts material under - strain
strain - results in - deformation

Question 20

3 zones of stress + strain

Answer 20

1. elastic region - goes back to normal condition.
2. plastic region - dent - deformed material
3. failure region - brake material

Question 21

Brittle vs ductile

Answer 21

Brittle = shorter deformation zone - concrete or glass
ductile = long deformation zone - mild steel or metal

Question 22

ductility

Answer 22

the ability to sustain large plastic deformations without failing. ex : gold, aluminum

Question 23

brittleness

Answer 23

the ability sustain very little deformation before fracturing or failing
ex: glass, ceramics

Question 24

yield strength

Answer 24

the point where a material under stress will not return to its original shape. no going back

Question 25

elasticity

Answer 25

the ability of a material to return to its original form after being deformed by an applied stress

Question 26

plasticity

Answer 26

the inability of a material to return to its original form after stress has been applied to it