Yapıların plastik enerji dengesine göre sismik tasarımı

Year 2018, Volume: 24 Issue: 3, 350 - 361, 29.06.2018

Onur Merter Taner Uçar

Abstract

Yapı
sistemlerinin doğrusal olmayan analizi ve tasarımında enerji kavramına dayalı
hesaplamalar, yer değiştirme esaslı yöntemlere bir alternatif olarak
gelişmektedir. Enerjiye dayalı yapı tasarımı aynı zamanda yer değiştirme
kavramını da içermekte ve diğer analizlere kıyasla daha rasyonel bir yöntem
olarak anılmaktadır. Çalışmada kullanılan yöntemde, deprem etkisi yapıya bir
enerji girişi olarak ele alınmakta ve yapı sistemi için genel enerji denge
denklemi yazılmaktadır. Plastik mafsalların kiriş uçlarında ve kolon alt
uçlarında oluştuğu ideal göçme mekanizması esas alınmaktadır. Yapı için bir
göreli kat ötelemesi oranının hedeflenmesi ile tasarım yatay kuvvetlerinin
sistem üzerinde yaptığı dış işin genel enerji dengesinden elde edilen plastik
enerji ile eşitlenmesi sonucunda taban kesme kuvveti ifadesi türetilmektedir.
Enerji esaslı taban kesme kuvvetinin seçilen 3 ve 5 katlı çelik çerçeve
yapıların kat seviyelerine eşdeğer statik yük olarak etkitilmesinin ardından,
belirli bir yönetmeliğe göre önceden boyutlandırılmış yapı taşıyıcı sisteminin
plastik tasarımı belirlenen yeni taban kesme kuvvetine göre tekrarlanmaktadır.
İteratif bir yaklaşım sunan tasarım yönteminde, bir önceki iterasyonun kesit
boyutları elde edilene dek tasarım devam etmektedir. Tasarım sonucunda
belirlenen taşıyıcı sistemin, enerji esaslı taban kesme kuvveti ile doğrusal
olmayan artımsal itme analizinden belirlenen göreli kat ötelemesi oranları ile
tasarımda hedeflenen göreli kat ötelemesi oranı karşılaştırılmaktadır. Esas
alınan ideal göçme mekanizması durumunun oluşup-oluşmadığı kontrol
edilmektedir. Sonuçlar ölçekli gerçek deprem ivme kayıtları ile
gerçekleştirilen zaman tanım alanında doğrusal olmayan dinamik analizlerin
verdiği sonuçlarla karşılaştırılıp, yorumlanmaktadır.

Keywords

Enerjiye dayalı tasarım, Enerji denge denklemi, Enerji esaslı taban kesme kuvveti, Plastik tasarım, Doğrusal olmayan statik ve dinamik analiz

Seismic design of structures based on plastic energy balance

Abstract

Energy-based
approaches are developed as an alternative to displacement-based methods in
nonlinear analysis and design of structures. The structural design methodology
based on energy concepts incorporates the displacement concept simultaneously
and it may be mentioned more rational by comparison with the other existing
methods. Earthquake is considered as an energy input to the structure within
the study and then the general energy-balance equation is written for the
structure system. Ideal collapse mechanism, where plastic hinges are assumed to
be located on beam ends and column bases, is considered. An admissible
interstory drift ratio is targeted for the design and base shear force
expression is derived by equating the plastic energy from general
energy-balance with the external work done by the design lateral forces. The
new energy-based base shear force is distributed to story levels of 3- and
5-story steel structures as equivalent static lateral forces and then plastic
design of structural system, which is predesigned that comply with a seismic
code at the beginning of the methodology, is implemented. The structural design
method involves an iterative technique and it is continued until the same
sections of the former iteration are obtained. The interstory drift ratios
obtained from pushover analysis using the inverted triangular distribution of
energy-based base shear force are compared with the target drift of the design.
The accepted ideal collapse mechanism is checked whether it occurs or not. The
results are interpreted and compared to the results of nonlinear time history
analyses performed by using the time histories of real earthquakes scaled in
time domain.

Keywords

Energy-based design, Energy-balance equation, Energy-based base shear force, Plastic design, Nonlinear static and dynamic analysis

References

• Applied Technology Council. “ATC40 Seismic Evaluation and Retrofit of Concrete Buildings Volume 1”. California, USA, SSC 96-01, 1996.
• Federal Emergency Management Agency. “FEMA 356 Prestandard and Commentary for the Seismic Rehabilitation of Buildings”. Washington, DC, USA, 2000.
• Federal Emergency Management Agency. “FEMA 440 Improvement of Nonlinear Static Seismic Analysis Procedures”. Washington, DC, USA, 2005.
• Structural Engineers Association of California. “Vision 2000 Performance Based Seismic Engineering of Buildings”. Sacramento, CA, USA, 1995.
• Akbaş B, Shen J. “Earthquake resistant design and energy concepts”. Technical Journal of Turkish Chamber of Civil Engineers, 14(2), 2877-2901, 2003.
• Bertero VV, Teran-Gilmore A. Use of Energy Concepts in Earthquake-Resistant Analysis and Design: Issues and Future Directions. Advances in Earthquake Engineering Practice: Series 2, University of California, Berkeley, 1994.
• Leelataviwat S, Goel SC, Stojadinovic B. “Energy based seismic design of structures using yield mechanism and target drift”. ASCE Journal of Structural Engineering, 128(8), 1046-1054, 2002.
• Teran-Gilmore A, Avila E, Rangel G. “On the use of plastic energy to establish strength requirements in ductile structures”. Engineering Structures 25(7), 965-980 2003.
• Khashaee, P, Mohraz B, Sadek F, Lew HS, Gross JL. “Distribution of Earthquake Input Energy in Structures”. The National Institute of Standards and Technology (NIST), Building and Fire Research Laboratory, NISTIR 6903, USA, 2003.
• Fajfar P, Vidic T, Fischinger M. “On the energy input into structures”. Proceedings of the Pacific Conference on Earthquake Engineering, Auckland, New Zealand, 20-23 November 1991.
• Zahrah TF, Hall WJ. “Earthquake energy absorption in SDOF structures”. Journal of Structural Engineering, 110(8), 1757-1773, 1984.
• Leelataviwat S, Saewon W, Goel SC. “Application of energy balance concept in seismic evaluation of structures”. Journal of Structural Engineering, 135(2), 113-121, 2009.
• Akiyama H. Earthquake-Resistant Limit State Design for Buildings. Japan, The University of Tokyo Press, 1985.
• Housner GW. “Limit design of structures to resist earthquakes”. The First World Conference on Earthquake Engineering, Berkeley, California,12-15 June 1956.
• Chopra AK. Dynamics of Structures, Theory and Applications to Earthquake Engineering. Upper Saddle River, NJ, USA, Prentice Hall, 1995.
• Kuwamura H, Galambos T. “Earthquake load for structural reliability”. Journal of Structural Engineering, 115(6), 1446-1462, 1989.
• Fajfar P, Vidic T. “Consistent inelastic design spectra: hysteretic and input energy”. Earthquake Engineering & Structural Dynamics, 23(5), 523-537, 1994.
• Benavent-Climent A, Pujades LG, Lopez-Almansa F. “Design energy input spectra for moderate seismicity regions”. Earthquake Engineering & Structural Dynamics, 31(5), 1151-1172, 2002.
• Benavent-Climent, A, Lopez-Almansa F, Bravo-Gonzales DA. “Design energy input spectra for moderate-to-high seismicity regions based on Colombian earthquakes”. Soil Dynamics and Earthquake Engineering, 30(11), 1129-1148, 2010.
• Bai J, Ou J. (2012). “Plastic limit-state design of frame structures based on the strong-column weak-beam failure mechanism”. 15th World Conference on Earthquake Engineering, Lisboa, Portugal, 24-28 September 2012.
• Çevre ve Şehircilik Bakanlığı. “Çelik Yapıların Tasarım, Hesap ve Yapım Esaslarına Dair Yönetmelik”. Ankara, Türkiye, 2016.
• Zahrah TF, Hall WJ. “Earthquake energy absorption in SDOF structures”. Journal of Structural Engineering, 110(8), 1757-1773, 1984.
• Uang CM, Bertero VV. “Use of Energy as a Design Criterion in Earthquake Resistant Design”. Earthquake Engineering Research Center, University of California, Berkeley, USA, UCB/EERC-88/18, 1988.
• Manfredi G. “Evaluation of seismic energy demand”. Earthquake Engineering & Structural Dynamics, 30(4), 485-499, 2001.
• Lopez-Almansa F, Yazgan AU, Benavent-Climent A. “Design energy input spectra for high seismicity regions based on Turkish registers”. Bulletin of Earthquake Engineering, 11(4), 885-912, 2013.
• Leelataviwat S, Goel S, Stojadinović B. "Energy-based seismic design of structures using yield mechanism and target drift". Journal of Structural Engineering, 128(8), 1046-1054, 2002.
• International Conference of Building Officials. “Uniform Building Code”. Whittier, California, USA, 1994.
• International Conference of Building Officials. “Uniform Building Code”. Whittier, California, USA, 1997.
• European Committee for Standarization. “Eurocode 8: Design of Structures for Earthquake Resistance-Part 1: General Rules, Seismic Actions and Rules for Buildings”. Brussels, 2004.
• Kalkan E, Kunnath SK. “Effective cyclic energy as a measure of seismic demand”. Journal of Earthquake Engineering, 11(5), 725-751, 2007.
• Bayındırlık ve İskan Bakanlığı. “Deprem Bölgelerinde Yapılacak Binalar Hakkında Yönetmelik”. Ankara, Türkiye, 2007.
• Yüksel İ, Polat Z. “Betonarme çerçeve sistemlerinde sistem akma parametrelerinin tespiti”. Uluslararası Yapı ve Deprem Mühendisliği Sempozyumu, Ankara, Türkiye, 14 Ekim 2002.
• Tjhın TN, Aschheim MA, Wallace JW. “Yield displacement estimates for displacement-based seismic design of ductile reinforced concrete structural wall buildings”. The 13th World Conference on Earthquake Engineering, Vancouver, Canada, 1-6 August 2004.
• Özer E. Yapı Sistemlerinin Lineer Olmayan Analizi. İstanbul, Türkiye, Ders Notu, İTÜ, 2004.
• Computers and Structures Inc. “SAP2000 Ultimate: Integrated Solution for Structural Analysis and Design”. Structural Analysis Program, Version 18.0.1, Berkeley, CA, 2015.
• Liao WC. Performance-Based Plastic Design of Earthquake Resistant RC Moment Frames. PhD Thesis, The University of Michigan, Ann Arbor, USA, 2010.
• Pacific Earthquake Engineering Research Center. “PEER Ground Motion Database”. http://ngawest2.berkeley.edu/ (12.12.2015).
• Seismosoft Ltd. “SeismoSpect v2.1.2”. Italy, 2015.