pp. 431-445 | Article Number: iejme.2017.021
Published Online: June 18, 2017
Article Views: 477 | Article Download: 720
Constructing plastic hinges and the way of their distribution and failure mechanism can play an important role on seismic structures design. Mechanism type affect frame sensitivity toward secondary effects, total and local ductility, energy absorption and structure resistance before damage, general instability and destruction. Failure mechanism of moment frames under earthquake effect could be mentioned as three general types (first, second and third). The first type resulted from constructing hinges in beams and columns in the first few -story up, the second one resulted from constructing hinges in beams and columns of few upper -story and the third type including mechanism of one middle floor. Failure mechanism of general type is a special mode of the second type mechanism in which, plastic hinges locating at the two ends of beams and the first floor columns near the connection to the foundation. Based on researches, this type of mechanism shows the most amount of energy absorption against earth quack. Knee bracing frame is appropriate as an energy dissipation system composed of ductility and lateral stiffness which has good performance against lateral loads specially earthquake. In this paper, forming plastic hinges of components and the base shear of different steel systems and comparing them with knee bracing lateral load system in three, five and seven -story frames using regulations of FEMA356 and ATC-40.
Keywords: Plastic hinge, Steel frames, Knee bracing
Kalkan E. and Kunnath S. K. (2004), "Method of modal combinations for pushover analysis of buildings," in Proc. Of the 13 th World Conference of Earthquake Engineering.
Khatib I. F., Mahin S. A., and Pister K. S. (1988), Seismic behavior of concentrically braced steel frames vol. 88: Earthquake Engineering Research Center, University of California.
Uriz P. (2008), Toward earthquake-resistant design of concentrically braced steel-frame structures: Pacific Earthquake Engineering Research Center.
Aristizabal-Ochoa J. D. (1986), "Disposable knee bracing: improvement in seismic design of steel frames," Journal of Structural Engineering, vol. 112, pp. 1544-1552.
Roeder C. W.and Popov E. P. (1978), "Eccentrically braced steel frames for earthquakes," Journal of the Structural Division, vol. 104, pp. 391-412.
Naeemi M. and Bozorg M. (2009), "Seismic Performance of Knee Braced Frame," Proceedings of World Academy of Science: Engineering & Technology, vol. 50,pp 976-980.
Kim J.and Seo Y. (2003), "Seismic design of steel structures with buckling-restrained knee braces," Journal of Constructional Steel Research, vol. 59, pp. 1477-1497.
Balendra T., Sam M. T., and Liaw C. Y. (1990), "Diagonal brace with ductile knee anchor for aseismic steel frame," Earthquake engineering & structural dynamics, vol. 19, pp. 847-858.
Agency F. E. M. (2000), "Prestandard and Commentary for the Seismic Rehabilitation of Buildings: FEMA-356," ed: Federal Emergency Management Agency Washington.
Code U. B. (1997), "UBC 97, Code for Seismic Design of Buildings (1997 Edition)," Structural Engineering Design Provisions, vol. 2.
Balendra T., Sam M.-T., Liaw C.-Y., and Lee S.-L. (1991), "Preliminary studies into the behaviour of knee braced frames subject to seismic loading," Engineering Structures, vol. 13, pp. 67-74.
FEMA A. (2005), "440, Improvement of nonlinear static seismic analysis procedures," ed: Federal Emergency Management Agency, Washington DC.
Elnashai A. S. (2001), "Advanced inelastic static (pushover) analysis for earthquake applications," Structural engineering and mechanics, vol. 12, pp. 51-70.
Krawinkler H.and Seneviratna G. (1998), "Pros and cons of a pushover analysis of seismic performance evaluation," Engineering Structures, vol. 20, pp. 452-464
Chopra A. K.and Goel R. K. (2002), "A modal pushover analysis procedure for estimating seismic demands for buildings," Earthquake engineering & structural dynamics, vol. 31, pp. 561-582.
Chopra A. K., Goel R. K., and Chintanapakdee C. (2004), "Evaluation of a modified MPA procedure assuming higher modes as elastic to estimate seismic demands," Earthquake Spectra, vol. 20, pp. 757-778.
Ghodrati,A and Eghbali,M (2011)"New method of two line pushover for seismic evaluation of steel frames. 5th natinal congress of construction engineering. Mashhad.