Performance Comparison of Concrete Moment Frames Designed by Direct Displacement Based and Force Based Methods

Document Type : Original Article

Authors

1 Assistant professor, Department of civil engineering, University of Kashan, Kashan, Iran

2 MSc Structural Engineering, Department of civil engineering, University of Kashan, Kashan, Iran

3 Ph.D candidate in Structural Engineering, Department of civil engineering, University of Semnan, Semnan, Iran

Abstract

Performance-Based Design Methods idea is based on decreasing the structural damages in earthquake, according to client requirements, it seems be an economical design method. There are two different Performance based design approaches, the former is direct approach and the latter is indirect approach. In direct approach the level of performance is assumed at the beginning of design procedure and design has been performed to achieve the assumed performance. Direct displacement-based design method (DDBD) is known as direct approach. In DDBD procedure performance of the structure is predefined by assuming the total structural drift against specified earthquake level. In DDBD method, structural base shear is calculated according to occurrence of mechanism in earthquake. Therefore DDBD seems to be more realistic in comparison to force based design (FBD) because of considering the structural nonlinearities directly in calculations. In this paper, the principles of DDBD are explained, then concrete special moment frames of 4, 8, 12, 16 stories were designed by both of DDBD and FBD methods. It is concluded that columns dimensions and reinforcement in DDBD will be obtained equal or greater than FBD. In addition, longitudinal reinforcements at the middle span of beams in the frames of DDBD are more than the two ends which are the possible locations of plastic hinges. Frames evaluation by push-over analysis shows that DDBD frames responses are more compatible with plastic mechanism which is supposed in design procedure. Also it is concluded that the maximum drift of DDBD frames before collapse are usually greater than FBD ones and in DDBD frames plastic hinge formation in upper stories is more than FBD frames.

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[1] Priestley M, Calvi G, Kowalsky M. (2007). Direct displacement-based seismic design of structures. 5th New Zealand Society for Earthquake Engineering Conference.
[2] Bertero VV. (2000). Performance-based seismic engineering: conventional vs. innovative approaches.  Memorias 12vo Congreso Mundial de Ingeniería Sísmica.
[3] Priestley M. (2000). Performance based seismic design. Bulletin of the New Zealand society for earthquake engineering.
[4] Shibata A, Sozen MA. (1976). Substitute-structure method for seismic design in R/C. Journal of the Structural Division.
[5] Dwairi HM, Kowalsky MJ, Nau JM. (2007). Equivalent damping in support of direct displacement-based design. Journal of Earthquake Engineering.
[6] Blandon CA. (2004). Equivalent viscous damping equations for direct displacement based design.‏ Master. ROSE SCHOOL.
[7] Pettinga JD, Priestley MN. (2005). Dynamic Behaviour of Reinforced Concrete Frames Designed with Direct Displacement-Based Design. ROSE SCHOOL.
[8] Muljati I, Kusuma A, Hindarto F.  (2015). Direct Displacement Based Design on Moment Resisting Frame with Out-of-plane Offset of Frame. Procedia Engineering. 125:1057-64.
[9] Priestley M, Grant DN, Blandon CA. (2007). Direct displacement-based seismic design.  2005 NZSEE Conference.
[10] FEMA P.  (2000). Commentary for the seismic rehabilitation of buildings.  FEMA-356, Federal Emergency Management Agency, Washington, DC.
[11] Priestley M, Calvi G, Kowalsky M. (2007). Displacement‐based seismic design of structures. 1st ed. Pavia, Italy: IUSS Press.
[12] ACI. (2014). Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14). American Concrete Institute.
[13] ASCE. (2010). Minimum Design Loads for Buildings and Other Structures (ASCE 7-10). American Society of Civil Engineers.
[14] Bommer JJ, Elnashai AS. (1999). Displacement spectra for seismic design. Journal of Earthquake Engineering. 3:1-32.
[15] شاکری ک, شایانفر م. (۱۳۸۷). تحلیل استاتیکی غیر خطی مودال با یک بار اجرا برای ارزیابی لرزه‌ای قاب‌های خمشی فولادی. نشریه‌ی علمی و پژوهشی سازه و فولاد.
[16] Abbasnia R, Tajik Davoudi A, Maddah MM. (2014). An improved displacement-based adaptive pushover procedure based on factor modal combination rule. Earthquake Engineering and Engineering Vibration. 13:223-41.
[17] ASCE. (2013). Seismic Evaluation and Retrofit of Existing Buildings (ASCE 41-13). American Society of Civil Engineers.