Structural reliability of a RC beam considering different preliminary designs
DOI:
https://doi.org/10.34117/bjdv9n11-009Keywords:
structural reliability, preliminary structural design, reinforced concrete beams, Monte Carlo simulationAbstract
In the last decades, most of the structural designs around the world have been made by employing semi-probabilistic approaches based on partial safety factors. These practical methods allow the engineer to deal with the safety of structures without the need to directly address the uncertainties involved. The simplicity of these approaches depends on the fact that the same values of the safety factors must be applicable to a large number of different cases; this typically leads to dispersion in the structural reliability levels. The present paper aims at quantifying such dispersion within a specific scenario, regarding RC structures, in a way different from those found in the literature. It focuses on a simple residential building, for which seven preliminary design solutions are proposed by different engineers, and seven different structures are obtained from these solutions, considering the specifications given by the Brazilian structural design code ABNT NBR 6118:2014. The structural reliability indexes of a continuous beam, common to all solutions, are assessed and compared. The results indicate that, even in this specific case, the variability related to the safety levels is significant. Furthermore, in some cases the reliability index is found to be below the target levels provided by international structural standards.
References
Brazilian Association of Technical Standards (2014) ABNT NBR 6118 - Design of concrete structures – procedures. Rio de Janeiro, Brazil (in Portuguese)
Harty N, Danaher M (1997) Evaluating preliminary structural designs in an expert system. Computers & Structures 63(6):1243-1249
ACI Committee 318 (2019) Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary (ACI 318R-19). American Concrete Institute, Farmington Hills, Michigan
Nowak AS (1995) Calibration of LRFD Bridge Code. ASCE Journal of Structural Engineering 121(8):1245-1251
Ellingwood B (2000) LRFD: implementing structural reliability in professional practice. Engineering Structures 22:106-115
Sorensen JD, Hansen SO, Arnbjerg Nielsen T (2001) Calibration of partial safety factors for Danish Structural Codes. In: Proc. IABSE Conf. Safety, Risk and Reliability – Trends in Engineering, Malta, IABSE, pp 179-184
Szerszen M, Nowak AS (2003) Calibration of design code for buildings (ACI 318): Part 2 – Reliability analysis and resistance factors. ACI Structural Journal 100(3):383-391
Beck AT, Souza Jr AC (2010) A first attempt towards reliability-based calibration of Brazilian structural design codes. J. of the Braz. Soc. Of Mech. Sci. & Eng. 32:119-127
Kotes P, Prokop J, Strieska M, Vican J (2017) Calibration of partial safety factors according to Eurocodes. In: XXVI R-S-P Seminar 2017 Theoretical Foundation of Civil Engineering, MATEC Web Conf. 117:1–8
Szerszen M, Szwed A, Nowak AS (2005) Reliability analysis for eccentrically loaded columns. ACI Structural Journal 102(5):676-691
Stucchi FR, Santos SHC (2007) Reliability based comparison between ACI 318-05 and NBR 6118. IBRACON Structural Journal 3(2):230-239
Beck AT, Doria AS (2008) Reliability Analysis of I-Section Steel Columns Designed According to New Brazilian Building Codes. J. of the Braz. Soc. Of Mech. Sci. & Eng. 30:152-159
Beck AT, Oliveira WLA, De Nardin S, El Debs ALHC (2009) Reliability-based evaluation of design code provisions for circular concrete-filled steel columns. Engineering Structures 31(10):2299-2308
Chaves AC, Beck AT, Malite M (2010) Reliability-Based evaluation of Design Guidelines for Cold-Formed Steel-Concrete composite beams. J. of the Braz. Soc. Of Mech. Sci. & Eng. 32:442-449
Santos DM, Stucchi FR, Beck AT (2014) Reliability of beams designed in accordance with Brazilian codes. IBRACON Structures and Materials Journal 7(5):723-746
Nogueira CG, Pinto MDT (2016) Safety variability assessment of reinforced concrete beams subjected to bending moment considering the NBR 6118:2014 safety partial factors. IBRACON Structures and Materials Journal 9(5):682-709
Fröderberg M, Thelandersson S (2015) Uncertainty caused variability in preliminary structural design of buildings. Structural Safety 52:183–193
Faber MH (2012) Statistics and Probability Theory: In Pursuit of Engineering Decision Support. Springer Publishing Company, Topics in safety, risk, reliability and quality
Melchers RE, Beck AT (2018) Structural reliability analysis and prediction. Hoboken, John Wiley & Sons, New York
Madsen HO, Krenk S, Lind NC (1986) Methods of Structural Safety. Prentice-Hall, Englewood Cliffs, NJ
Haldar A, Mahadevan S (2000) Probability, reliability and statistical methods in engineering design. John Wiley & Sons, New York
Ditlevsen O, Madsen HO (2005) Structural Reliability Methods. Technical University of Denmark, Department of Mechanical Engineering, Kongens Lyngby
Awruch AM, Gomes HM (2013) Reliability analysis of reinforced concrete structures with a methodology to account stochastic effects of material properties. Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería 30(2):85-96 (in Portuguese)
Novaes RFP, Ricardo AS, Silva JPM, Simionatto BM (2021) Structural reliability analysis of a marquee element. Brazilian Journal of Development 7(2):11928-11941.
Zhang H (2018) Durability reliability analysis for corroding concrete structures under uncertainty. Mechanical Systems and Signal Processing 101:26–37
Mohamed A, Soares R, Venturini WS (2001) Partial safety factors for homogeneous reliability of nonlinear reinforced concrete columns. Structural Safety 23:137-156
Eamon CD, Jensen E (2013) Reliability analysis of RC beams exposed to fire. Journal of Structural Engineering 139(2):212-220
Baji H, Ronagh HR, Melchers RE (2016) Reliability of ductility requirements in concrete design codes. Structural Safety 62:76–87
EN 1990 (2002) Eurocode: Basis of Structural Design. European Committee for Standardization (CEN), Brussels
Stucchi FR, Santos SHC (2010) Evaluation of the safety criteria of Brazilian Standard NBR 6118 based on reliability analyses. In: Joint IABSE fib Conference: Codes in Structural Engineering
Kong FK, Evans RH (1987) Reinforced and Prestressed Concrete. Wokingham, Van Nostrand Reinhold
Mahsuli M, Haukaas T (2013) Computer program for multimodel reliability and optimization analysis. Journal of Computing in Civil Engineering 27:87-98
Brazilian Association of Technical Standards (1980) ABNT NBR 6120 – Loads for building structures design. Rio de Janeiro, Brazil (in Portuguese)
Brazilian Association of Technical Standards (1988) ABNT NBR 6123 – Wind loads in buildings – Procedure. Rio de Janeiro, Brazil (in Portuguese)
Altoqi (2017) Software Eberick – V10 version. AltoQI Computer Technology Ltda, Santa Catarina, Brazil
Caixa Economica Federal (2017) SINAPI – Indexes of Construction. https://webp.caixa.gov.br/casa/sinapi/index.asp?menu=1. Accessed 18October 2017
Aoues Y, Chateauneuf A (2008) Reliability-based optimization of structural systems by adaptive target safety – Application to RC frames. Structural Safety 30(2):144–161
Mitropoulou CC, Lagaros ND, Papadrakakis M (2011) Life-cycle cost assessment of optimally designed reinforced concrete buildings under seismic actions. Reliability Engineering and System Safety 96(10):1311–1331
Beck AT, Gomes WJS, Lopez RH, Miguel LFF (2015) A comparison between robust and risk-based optimization under uncertainty. Structural and Multidisciplinary Optimization 52(3):479-492
Porto NGO, Pantoja JC, Rodrigues HP (2021) Probabilistic assessment of the safety and durability level of existing reinforced concrete structures based on inspections. Brazilian Journal of Development 7(8):84999-85010.
Furst A (2020) Model erros and structural reliability of reinforced concrete beams. Dissertation (Master of Science), Federal University of Santa Catarina, Florianópolis (in Portuguese)
