Evaluation of Safety Index and Calibration of Load and Resistance Factors for Reinforced Concrete Beams under Bending, Shear and Torsion Demands

Document Type : Original Article

Authors

1 MSc, Malayer University, Malayer, Iran

2 Assistant Professor, Malayer University, Malayer, Iran

Abstract

The aim of designing of the structural members is withstanding the members or structures against the different loading conditions such that the safety of the system could be preserved. The conventional method for designing of reinforced concrete members in Iranian concrete code is based on load and resistance factor. Although, load and resistance parameters are random variables, and in the mentioned Code the constant values have been designated for them during the designing procedure. Accounting these factors as the constants parameters will ultimately be led to the unsafe and uneconomical designs. The main purpose of this paper is probability-based designing of reinforcement concrete beams under simultaneous effects of bending, shear and torsion actions. For this purpose, analytical relations of the limit states for combination of bending, shear and torsion have been developed. Using the method, the structural designers could be fulfilled the designing of the RC beams based on the importance of structures and the required safety indexes of the owners.  The next goal of this investigation is evaluation and calibration of load and resistance factors for desired safety index. The economic and fully probabilistic designing of concrete beams for simultaneous effects of bending, shear and torsion are available by implementing the proposed design procedures. In order to calculate the safety indexes a computer program has been written in the MATLAB environment, and the Monte Carlo simulation technique has been utilized.

Keywords

Main Subjects

References

[1] Ellingwood, B. R., & Ang, A. H. (1974). Risk-based evaluation of design criteria. Journal of the Structural   Division, 100(Proc. Paper 10778).
[2] Lu, R., Luo, Y., & Conte, J. P. (1994). Reliability evaluation of reinforced concrete beams. Structural Safety, 14(4), 277-298.
[3] Bentz, E. C., Vecchio, F. J., & Collins, M. P. (2007). Simplified modified compression field theory for calculating shear strength of reinforced concrete elements. 378-379
[4] Shao, L., & Li, C. Q. (2007). Reliability based asset management strategy for concrete infrastructure. International Journal of Materials and Structural Reliability, 5(1), 13-28.
[5] Nowak, A., & Kaszyńska, M. (2011). Target reliability for new, existing and historical structures.
[6] Porco, F., Uva, G., Sangirardi, M., & Casolo, S. (2013). About the Reliability of Punching Verifications in Reinforced Concrete Flat Slabs. Open Construction and Building Technology Journal, 7, 74-87.
[7] Jensen, D. F. (2014). Reliability Analysis For Shear In Lightweight Reinforced Concrete Bridges Using Shear Beam Database.
[8] Backes, M. R., Fernández Ruiz, M., & Muttoni, A. (2014). Interaction between in-plane shear forces and transverse bending moments in concrete bridge webs. In Proc. of the 10th fib International PhD Symposium in Civil Engineering, Quebec (No. EPFL-CONF-200971, pp. 403-408). Proc. of the 10th fib International PhD Symposium in Civil Engineering, Quebec.
[9] Trezos, C. G., & Thomos, G. C. (2002). Reliability Based Calibration οf the Greek Seismic Code.
[10] Szerszen, M. M., & Nowak, A. S. (2003). Calibration of design code for buildings (ACI 318): Part 2—Reliability analysis and resistance factors.Structural journal, 100(3), 383-391.
[11] Paik, I., Shin, S., & Shim, C. (2008). Reliability-based code calibration and features affecting probabilistic performance of concrete bridge.
 
[12] Mirza, S. A., & MacGregor, J. G. (1979). Variations in dimensions of reinforced concrete members. Journal of the Structural Division, 105(4), 751-766.
[13] MacGregor, J. G. (1983, July). Load and resistance factors for concrete design. In Journal Proceedings (Vol. 80, No. 4, pp. 279-287).
[14] Galambos, T. V., Ellingwood, B., MacGregor, J. G., & Cornell, C. A. (1982). Probability based load criteria: assessment of current design practice.Journal of the Structural Division, 108(5), 959-977.
[15] Paxton, P., Curran, P. J., Bollen, K. A., Kirby, J., & Chen, F. (2001). Monte Carlo experiments: Design and implementation. Structural Equation Modeling, 8(2), 287-312.
[16] National Building Regulations of Iran- part 9, design and construction of concrete buildings, 2011
[17] Choi, S. K., Grandhi, R. V., & Canfield, R. A. (2006). Reliability-based structural design. Springer Science & Business Media.
[18] MATLAB, "The Language of Technical Computing", (2008), Version 7.6.0. The Math-works Inc.: Natick, MA

Files

History

  • Receive Date: 05 April 2016
  • Revise Date: 21 November 2016
  • Accept Date: 22 December 2016

Share

How to cite

Statistics