Çelik döşeme sistemlerinde insan hareketleri etkisi ile oluşan titreşim sorunlarının incelenmesi
Investigation of the steel floor vibrations due to human 
activity
Yazar: HAKAN YILDIZ
Danışman: PROF. DR. CAVİDAN YORGUN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2014
Konu: İnşaat Mühendisliği = Civil Engineering

Özet:
Çelik döşeme sistemlerinde karşılaşılan en büyük sorunlardan bir tanesi insan veya
makine etkileri ile oluşan titreşimlerdir. Çelik profillerin taşıyıcı sistem tasarımında
kullanılmaya başlanması ile beraber ortaya çıkan bu sorun dinamik kuvvetler
etkisinde oluştuğu için hesaplanabilmesi zordur. Bu nedenle çok eski zamanlardan bu
yana kirişlerde deplasman sınırı L/360 alınarak döşeme titreşimlerinin önüne
geçilmeye çalışılmaktadır. Yakın zamana kadar bu yöntem tüm dünyada
kullanılmaktaydı, ancak yapılan çalışmalar ve araştırmalar neticesinde dinamik
yüklerin basitleştirilerek insan hareketleri etkisinde döşeme sistemlerinde oluşacak
titreşimlerin önüne geçilebilecek yeni yöntemler geliştirilmiştir. Bu çalışmada
deplasman sınırı yöntemi ile yeni geliştirilen hesap yöntemlerinden iki tanesi
karşılaştırılacaktır. Bu iki yöntemden ilki "AISC Design Guide 11" tasarım
kılavuzunda anlatılan hesap yöntemidir. İkinci hesap yöntemi ise "Human Induce
Vibration of Steel Structures" tasarım kılavuzuna göre yapılmıştır. Yapılan hesaplar
kıyaslanarak, yöntemlerin kullanılabilirliği değerlendirilmiştir.
İlk bölümde, dinamik etkiler altında döşeme sistemlerinde oluşan titreşimler
konusuna genel bir giriş yapılmakta ve tez çalışması için bu konunun seçilmesinin
amacı açıklanmaktadır.
İkinci kısımda insan hareketleri etkisinde döşeme sistemlerinde oluşan titreşimleri
kontrol altına alabilmek için yapılan çalışmalar tarih sırası ile anlatılmaktadır.
Çalışmanın üçüncü bölümünde çelik döşeme sistemlerinde titreşim sorunları
incelenirken, bilinmesi gereken temel teknik terimlerin açıklamaları yer almaktadır.
Dördüncü bölümde, insan ve makine etkileri ile döşeme sistemlerinde oluşan
titreşimler hakkında genel bilgilendirme yapılmaktadır. Ayrıca yürüme hareketi gibi
insan hareketleri nedeni ile oluşan dinamik ve tekrarlı kuvvetlerin fourier
dönüşümleri yardımı ile sinüzoidal kuvvetlere dönüştürülmesi anlatılmaktadır.
Beşinci bölümde, döşeme sistemlerinde ortaya çıkan titreşimlerin, döşemeyi kullanan
insanlar üzerinde oluşturduğu olumsuz etkiler ve bu etkilerin hissedilebilmesi için
gerekli olan eşik değerler üzerinde durulmaktadır.
Altıncı bölümde, döşemelerin doğal titreşim hareketinin hesaplanması ve doğal
titreşim hareketi frekansının bağlı olduğu kıstaslar açıklanmaktadır.
Yedinci bölümde ise insan hareketleri etkisi ile örnek bir döşeme sisteminde
meydana gelecek titreşim sorunlarının önüne geçebilmek için deplasman sınırı
yöntemi, "AISC Design Guide 11" tasarım kılavuzu ve "Human Induce Vibration of
Steel Structures" tasarın kılavuzu yardımı ile hesaplar yapılarak bu üç yöntem
sonucunda elde edilen veriler kıyaslanmıştır. Yapılan kıyaslama sonucunda
yöntemlerin kullanılabilirlikleri değerlendirilmiştir.

Abstract:
In recent years construction methods and design have been developed for example
spans are getting larger and lightweight construction profiles are being used in
construction systems. One of the common problem is vibration as a result of these
developments Excessive floor vibration has become a greater problem as new
rhythmic activities, such as aerobics and long-span floor structures have become
more common.
Vibration can be caused by humans or machinery effects in steel floor systems.
Humans are both source and the sensor and they can be very sensitive to vibration.
Controlling annoying vibration with machine equipment is not possible, it must be
isolated by structural system. The problems about floor vibration first investigated by
Tredgold in 1828, Tredgold wrote 'girders should always be made as deep as they
can to avoid the inconvenience without shaking everything in room.
Floor vibration criteria have been developing since 1966. Studies hasn't been
significant but general guidelines are available. In this thesis AISC Steel Design
guide 11, Floor vibration due to Human activities and Human Induced Vibration of
Steel Structures, Vibration design of floors guideline were used for evaluating
vibration. Generally it is not the participants in a particular activity or event who are
most disturbed floor vibration but those who are located in adjacent spaces, as they
find it annoying or disruptive to their own activities.
Several parameters are taken in consideration when assessing vibrations.
· Frequency:
Natural frequency is the frequency at which a body or structure will vibrate
when displaced and then quickly released.
· Mode Shape:
When a floor system vibrates freely in a particular mode, it moves up and
down with a certain configuration or mode shape.
· Damping:
Damping refers to the loss of mechanical energy in vibrating system.
Damping usually expresses as the percent of critical damping or as the ratio
of actual damping to critical damping.
· Resonance:
If a frequency component of an exciting force is equal to natural frequency of
the structure, resonance will occur.
Scope of thesis is issued in first chapter. Purpose of study and related design guides
are summarized in this chapter.
Historical development of vibration problems are defined and required technical
terms are explained in Second Chapter.
General technical terms are described in third Chapter.
Vibration occurs in steel floor structure due to human and machine effects are
discussed in fourth chapter. Besides dynamic and continuous forces which is caused
by human activities (walking excitations) are converted to sinusoidal forces in this
chapter.
Negative effects of vibration on occupants which occurs in steel floor systems are
described in fifth Chapter. Occupants are sensitive for vibration and peak vibration
values are discussed in this section.
Calculation of natural vibration due to human activities and criteria for natural
vibration are assigned in sixth Chapter.
Vibration limits are expressed in terms of acceleration, as a percentage of
acceleration due to gravity (g). Vibration limit depends on what people are doing
when they experience the vibration. Occupants in office buildings are exposed to
different percentage of vibration people doing aerobics. Case study is solved by
deflection limit state, AISC Design Guide 11 and Humana Induce Vibration of Steel
Structures design guide to prevent from vibration due to Human activities. These
design guides are compared with each other in last chapter. It can be clearly seen that
design guides are applicable for steel floor systems as a result of evaluation.
Office floor system is analyzed by SAP 2000 software and floor system is designed
according to AISC 360-10 design guide, Load and Resistance Factor design rules are
followed. Assessed beam sections are checked by three design guide methods to
prevent from vibration due to human activities.
First vibration check method is deflection limit state. Steel floor's deflection
shouldn't be exceeded L/360 for limit state. This method has been using for many
years. Sections are not adequate when calculations are made by this method therefore
sections are enhanced. Hence weight of steel used in floor system is increased by
%35 percentages.
Second vibration check method is done by AISC Design Guide 11. Steel sections
satisfy the design requirements and criteria. However peak acceleration value for the
office buildings and steel floor system's acceleration are nearly same.
Finally steel floor system is checked by Human Induce Vibration of Steel Structures
design guide. Basically AISC Design Guide and Human Induce Vibration of Steel
Structure design are similar with each other. Both of guides are using the same
calculations. However some of formulas and tables are different. Vibration criteria is
provided by beam steel sections as stated in Human induce Vibration of steel
Structures.
Although AISC Design guide 11 and Human Induce Vibration of Steel Structures
design guide are quite different, beam steel sections satisfy the vibration criteria in
our case study. So steel sections are adequate. However steel sections are not
provided design criteria due to deflection limit state, sections properties needs to be
increase.
Vibration problems due to human activities are generally occurred by resonance and
for light frame construction, sudden deflections due to footsteps. Vibration can be
isolated by stiffening the floor structure. Proper placement of an activity or
machinery in the building is the most important consideration. To conclude with AISC 
Design guide 11 or Human Induce vibration of steel
structures design guide can be used for vibration control instead of deflection limit
state, results are more economical and accurate.