Simplified expressions for reliability assessments in code calibration. (1st April 2022)

• Record Type: Journal Article
• Authors: Arrayago, Itsaso; Zhang, Hao; Rasmussen, Kim J.R.
• Is Part Of: Engineering structures. Volume 256(2022)
• Publication Date: 2022-04-01
• Subjects: Code calibration -- Structural reliability -- Reliability index -- Partial safety factors -- Resistance factors -- FORM -- FOSM; Structural engineering -- Periodicals; Structural analysis (Engineering) -- Periodicals; Construction, Technique de la -- Périodiques; Génie parasismique -- Périodiques; Pression du vent -- Périodiques; Earthquake engineering; Structural engineering; Wind-pressure; Periodicals; 624.105
• DOI: 10.1016/j.engstruct.2022.114013
• Languages: English
• ISSNs: 0141-0296

Abstract

Highlights: Simplified reliability expressions are presented for simple cross-checks in code calibration. Expressions to estimate reliability indices β and resistance ϕ or safety factors γ M are proposed. Interrelationships between ϕ and γ M are investigated for gravity and gravity and wind load cases. Expressions allowing a direct comparison between the US and Eurocode frameworks are proposed. The accuracy of the expressions is assessed against FORM results. Abstract: First Order Reliability Methods (FORM) have been used by specification committees in the reliability analyses required for the calibration of resistance and safety factors for the past 40 years. However, these methods are iterative, require input information that may not be readily available, and make comparisons between different approaches or design frameworks difficult. This paper presents a set of simplified equations to estimate reliability indices β, resistance factors ϕ and partial safety factors γ M based on simpler First Order Second Moment (FOSM) considerations for the US and Eurocode frameworks, which are particularized for different load cases, and on the semi-probabilistic approach prescribed in the Eurocode 0. The equations provide direct relationships between the reliability calibration results corresponding to different design frameworks, and can be used to estimate resistance factors as simple cross-checks for the US framework based on the partial safety factors derived for the Eurocode (or vice versa) from basic statistical input information and given target reliability, including when the data available in the literature is insufficient to perform FORM analyses. The accuracy of the proposed equations is assessed against reliability results derived using FORM techniques for an extensive database of steel and stainless steel frames subjected to gravity and combined gravity plus wind load cases collected from the literature, and limitations for their applicability are recommended. The results demonstrate that the set of equations proposed in this paper provides accurate estimations of the reliability index β, resistance factors ϕ and partial safety factors γ M and can assist specification committees in the process of calibrating suitable ϕ and γ M -factors.