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[4] EG > Lesson 4-5: (P1) Dynamics of Vibration, Attenuation and Time History > Flashcards

Lesson 4-5: (P1) Dynamics of Vibration, Attenuation and Time History Flashcards

1
Q

arise from sudden movements in a rupture zone in the Earth’s crust

A

seismic waves

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2
Q

the upper part of the building remains in delay in respect to the foundation moving, due to its _____; this causes strong vibrations of the structure with _____ between the structure and the ground and hence large inertial force arise

A

mass; resonance phenomena

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3
Q

due to _____, the soil is overloaded, becoming stiffer, hence producing change in its behavior

A

building’s weight

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4
Q

for stiff soils, the weight effect is to _____ the acceleration peak

A

reduce

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5
Q

for soft soils, possible to observe a relative _____ in acceleration peaks due to the presence of a building

A

increasing

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6
Q

part of the vibrating energy of buildings is released into soil through waves produced by buildings

A

soil effect

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7
Q

the severity of shaking is controlled primarily by two (2) factors:

A
  • attenuation of ground motion
  • earthquake characteristics
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8
Q

the dissipation of seismic energy as seismic waves move through layers of varying soil and rock strata

A

attenuation of ground motion

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9
Q

characterized as the decrease in amplitude of the seismic waves with distance from source

A

attenuation of ground motion

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10
Q

it results from geometric spreading of propagating waves, energy absorption and scattering of waves

A

attenuation of ground motion

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11
Q

during earthquake, different structures will behave differently

A

earthquake characteristics

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12
Q

seismic waves can be modified by site characteristics, earthquake characteristics and structural performance

A

earthquake characteristics

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13
Q

3 important earthquake measurement parameters that measure ground motions at the ground surface

A
  • peak ground acceleration (PGA)
  • peak ground velocity (PGV)
  • peak ground displacement (PGD)
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14
Q

it has become the most popular parameter to denote the measure of an earthquake and has been related to the magnitude through several empirical relationship

A

peak ground acceleration (PGA)

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15
Q

these are essential for describing the important characteristics of strong ground motion in compact, quantitative form

A

ground motion parameters

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16
Q

the most common way of describing a ground motion is with time history

A

amplitude parameters

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17
Q

the peak ground acceleration (PGA) at a site depends not only on the magnitude and epicentral distance of the earthquake, but also on the _____

A

regional geological characteristics

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18
Q

as the PGA value decreases with the epicentral distance these empirical relationships are also called _____

A

attenuation laws

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19
Q

shaking depends on duration and frequency content, and to factors such as _____, _____, _____, and _____

A

length of fault rupture; focal depth; orientation of the fault; speed of rupture

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20
Q

large PGA earthquakes do not always create the most damage; in fact, a large PGA earthquake would produce _____ damage to some structures if it only occurs for a short time

A

little

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21
Q

shaking can be strengthen depending on the _____ along the path of the wave between the focus and the site, same as the _____ and _____

A

geologic conditions; soil conditions; topography

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22
Q

it is faster for hard rock than for soft soil

A

shear wave velocity

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23
Q

travel faster through hard rock than soft soil

A

seismic waves

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24
Q

local site characteristics greatly influence the seismic wave’s _____ and _____

A

frequency; amplitude

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25
Q

6 ground types based on shear-wave velocity to establish amplification effects for design purposes

A
  • type A
  • type B
  • type C
  • type D
  • type E
  • type F
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26
Q

this ground type is characterized by hard rock (igneous rock)

A

type A

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27
Q

this ground type is characterized by rock (volcanic rock)

A

type B

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28
Q

this ground type is characterized by very dense soil and soft rock (sandstone)

A

type C

29
Q

this ground type is characterized by stiff soil (mud)

A

type D

30
Q

this ground type is characterized by soft soil (artificial fill)

A

type E

31
Q

this ground type is characterized by soils requiring site-specific evaluations

A

type F

32
Q

this ground type has the largest stiffness and generates the smallest amplifications

A

type A

33
Q

this ground type is the softest and generates the largest amplifications

A

type E

34
Q

according to NSCP 2015, zone 2 has _____ seismic zone factor (Z)

A

0.20

35
Q

according to NSCP 2015, zone 4 has _____ seismic zone factor (Z)

A

0.40

36
Q

this seismic zone covers the provinces of Palawan, Sulu, and Tawi-Tawi

A

zone 2

37
Q

this seismic zone covers the rest of the country except Palawan, Sulu, and Tawi-Tawi

A

zone 4

38
Q

characteristics of a structure that have the largest influence on its response include _____ and _____

A

weight; stiffness

39
Q

damping can play a significant role when structures remain within the _____, but remains a much smaller effect for structures that deform into _____

A

elastic limit; inelastic behavior

40
Q

it has the greatest effect on structural response

A

stiffness

41
Q

the age and construction of structures play a major role in their performance during an earthquake; older and/ or poorly constructed structures are at a greater risk of failure during an earthquake because of inadequate _____, which is the ability of a structure to absorb the seismic energy

A

ductility

42
Q

branch of physics subdivided into statics

A

mechanics

43
Q

refers to the fact that the state of the system and the applied forces do not vary in time; they are time independent

A

static

44
Q

the study of systems subject to time-varying applied forces

A

dynamics

45
Q

as a consequence of the time variability of the applied forces, the system’s internal forces and its state (displacement/ deformation) also vary with time

A

the system’s response motion

46
Q

2 approaches to structural response

A
  • deterministic
  • non-deterministic
47
Q

this approach to structural response is prescribed dynamic loading, time variation of loading is known wherein the output provides displacement time history

A

deterministic

48
Q

this approach to structural response is random dynamic loading, uses statistical approach and provide statistical solution for displacement

A

non-deterministic

49
Q

4 characteristics and sources of typical dynamic loadings

A
  • harmonic load
  • complex period load
  • transient load
  • earthquake load
50
Q

the equilibrium condition is due to external force only (a = 0)

A

static condition

51
Q

the equilibrium condition is due to external and inertial forces (a ≠ 0)

A

dynamic condition

52
Q

considered as the study of a body or structure in dynamic equilibrium

A

structural dynamics

53
Q

the mathematical expression of dynamic equilibrium

A

equation of motion

54
Q

the equation of motion expresses the equilibrium of _____, _____, and _____

A

internal and external force terms; mass inertia; and damping effects

55
Q

all bodies possessing inertia (mass) and elasticity (degree of stiffness) are capable of _____

A

vibration

56
Q

a system put out of its equilibrium position and vibrates under the action of forces inherent in the system, and in the absence of external forces

A

free vibration

57
Q

a vibration that takes place under the action of external forces

A

forced vibration

58
Q

4 types of vibration

A
  • free, undamped vibration
  • free, damped vibration
  • forced, undamped vibration
  • forced, damped vibration
59
Q

the number of _____ is equal to the number of independent coordinates necessary to describe the motion of a system

A

degree of freedom (DOF)

60
Q

4 example of multiple degree of freedom system (MDOF)

A
  • 3 DOF
  • 6 DOF
  • 9 DOF
  • 18 DOF
61
Q

3 masses are fully concentrated and are constrained so that the corresponding mass points translate only in vertical direction

A

3 DOF

62
Q

if the 3 masses are not fully concentrated and they possess finite rotational inertia, the rotational displacements of the 3 points will be considered

A

6 DOF

63
Q

if axial distortions of the beam are significant and will result to translation displacement parallel with the beam axis

A

9 DOF

64
Q

if the structure’s mas deforms in 3D space

A

18 DOF

65
Q

the time required for the system to complete one cycle of the vibration

A

period (Tn)

66
Q

the natural period of vibration in units of seconds

A

period (Tn)

67
Q

the natural cyclic of vibration in units of hertz (Hz)

A

frequency (fn)

68
Q

the number of cycles per unit time (cycles per second)

A

frequency (fn)

69
Q

or the natural circular frequency of vibration in units of radians per second

A

circular (angular) frequency

[4] EG (5 decks)

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