Hidden safety in structural design codes

Abstract

Structural design codes are deliberately kept simple to facilitate the design process. To ensure sufficient safety with simplified models, parameters of these models are often chosen conservatively. This leads to additional “hidden safety” in the design. But what happens if one utilizes more advanced design models without the implicit conservatism of the simple models? On one hand, an advanced design method has the potential to result in more optimized designs. On the other hand, it will affect the structural safety. While the advanced models might be associated with smaller uncertainty, which increases reliability, the loss of hidden safety can decrease the reliability. We comprehensively discuss the role of hidden safety in codified structural design and its effects on the reliability and material consumption. Based on this, we develop a framework for adapting the safety concept to ensure that advanced models lead to the same level of safety as standard models. The framework is exemplarily applied to the wind load model of the Eurocode.