Calibration of simplified safety formats for structural timber design

Abstract

A framework for calibrating the reliability elements in simplified semi-probabilistic design safety formats is presented. The objective of calibration is to minimize the increase of construction costs, compared to the non-simplified safety format, without reducing the level of structural safety. The framework is utilized for calibrating two simplified safety formats which aim at reducing the number of load combinations relevant in structural timber design. In fact, the load-duration effect makes the design of timber structures more demanding since a larger number of load combinations need to be considered compared with other construction materials.Keywords: simplified safety formats, code-calibration, timber, reliability, load-duration effect. IntroductionCurrent standards for timber design, such as the Eurocode 5 [1], have reached a high level of sophistication, extensiveness, efficiency and completeness at a cost of increasing the number and complexity of design rules, principles and requirements. This is the result of a code-development process driven mainly by the need to extend the standards to new materials, solutions, technologies, calculation tools and mechanical models. The associated drawback is an increased, and sometimes unnecessary, complexity of structural design, particularly for common and simple structures. Therefore, code provisions should balance simplicity, economy, comprehensiveness, flexibility, innovation, and reality [2]. These properties are usually mutually

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