Omori static theory

1. Azərbaycan Respublikası Təhsil Nazirliyi
Azərbaycan Memarlıq və İnşaat Universiteti
«İnşaat» fakültəsi
«Bina və qurğuların istismarı və rekonstruksiyası» kafedrası
Fənnin adı: Qurğuların sınağı və zəlzələyə davamlığı
Mövzu: Determination of seismic loading by Omori's static theory
Məruzəçi: t.f.d., dosent Həsənova T.C.
MÜHAZİRƏNİN PLANI
1. History of development of methods of definition of seismic loadings
2. Definition of seismic loadings according to the static theory of Omori
3. Shortcomings of the static theory of Omori
ƏDƏBİYYAT
1. Мяммядов Ш.Я., Ящмядов Я.М., Рзайев Р.А., Зейналов А.Г. Гурьуларын
зялзяляйя давамлыьы, дярс вясаити, Бакы, 2003, 198 с.
2. Аьаларова Т.Ж. «Гурьуларын мцайиняси вя сынаьы» фянниндян
лабораторийа ишляри цзря методик эюстяриш. Бакы, 2008, 46 с.
3. Stein, Seth, and Michael Wysession. An introduction to seismology,
earthquakes, and earth structure. Malden, MA, Blackwell Pub., 2003. 498
p.Bibliography: p. 476-485.
4. Yeats, Robert S., Kerry Sieh, and Clarence R. Allen. The geology of
earthquakes. New York, Oxford University Press, 1997. 568 p. Bibliography:
p.500-549
5. Penelis, George G., and Andreas J. Kappos. Earthquake-resistant concrete
structures. London, New York, E & FN Spon, 1997. 572 p.
Kafedra iclasında
təsdiq olunmuşdur
12 sentyabr 2018-ciil
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Bakı-2018

2. HISTORY OF DEVELOPMENT OF METHODS
OF DEFINITION OF SEISMIC LOADINGS
The displacements of the soil arising at an earthquake have the chaotic
character which isn't keeping within any accurate forms of mathematical
regularity.
Therefore calculation of buildings and constructions on seismic influences in
all countries was based until recently on so-called "the static theory", F.Omori
offered by the Japanese scientist (1900). According to this theory, constructions
were considered as absolutely rigid bodies which at earthquakes move together
with the soil. Besides it was supposed that buildings thus have no rotary
conveyances. Thus, the speedups arising in constructions have to be the same, as at
its base, i.e. equal to speedups of a terrestrial surface. Therefore, forces of inertia
arising in any element of a design will be equal
 
t
y
m
J 0




(1)
F.Omori suggested to estimate seismic forces as the maximum forces of
inertia. In this formula the sign "-" showing that inertial force is lowered is directed
opposite speedup. At earthquakes of speedup can be directed diversely
    Q
K
t
y
g
Q
t
y
m
J
S s



 max
0
max
0
max




(2)
Q
K
S s

(3)
the seismicity coefficient which characterizes intensity of an earthquake, its size is
put depending on seismicity of the area.
 
g
t
y
Ks
max
0



 
t
y0 - displacement of the base (soil) during oscillations,
 
t
y0


- speedup of the base (soil) during oscillations,
m - mass of a construction,
Q - construction weight.

3. For determination of values of coefficient of seismicity of s
K Omori
carried out tests in brick piers and received the following values:
point
,
J 7 8 9
s
K 0,025 0,05 0,1
Practice showed that sometimes the displacements of constructions can
exceed soil displacement several times. In real life there are no absolutely rigid
constructions. To define Omori carried out dynamic tests of the brick columns
established on a platform, oscillating under the harmonious law.
Their tool measurements were necessary for determination of real sizes of
speedups at earthquakes. One of the first such measurements were the records
made during the Kant earthquake, Tokyo which has destroyed on September 1,
1923 and Yokohama.
The analysis of behavior of constructions at earthquakes already soon after
emergence of the static theory indicated a number of its shortcomings. First of all it
became clear that only very few constructions can be carried to number of the
absolutely rigid. Deformations of the majority of constructions are so essential that
forward displacements of their points concerning the base can be even big, than the
corresponding displacements of the base.