Structural design code of the 21th century
The development of rules to ensure the structural safety has a long history. Nowadays the semi probabilistic partial safety concept (e.g. the Eurocode) is state of the art. In this project we develop methods to further develop the partial safety concept to address the challenges posed by modern design methods. The goal is to optimize the material consumption/costs and structural safety, and to identify an optimal trade-off between these two attributes. In this context we investigate two different approaches:
Revealing hidden safety: The majority of models implemented in modern structural codes are kept simple to keep the designing process simple. These simplifications are often chosen in a conservative sense, meaning that they increase the structural resistance and lead to additional “hidden safety”. But what happens if these simplified and conservative models are replaced by more advanced and non-conservative models? On the one hand, this will decrease the required design resistances on average, hence decrease the material consumption and costs. On the other hand, it will affect the structural safety. However, it is not straight forward to evaluate if the structural safety increases or decreases: The loss of conservativeness itself decreases the structural safety. Simultaneously, the higher precision of advanced models decreases model uncertainty, hence increases the structural safety. Our research objective is to develop a framework to quantify the effects of hidden safety and to make suggestions on how to adapt the partial safety concept.
Design at system level: The default design - following the partial safety concept - is conducted at element/cross section level. Each element is individually verified to resist various actions. However, a failure at element level does not necessarily lead to system failure, since redundancies (e.g. static overdetermination) can compensate the element failure. Our research objective is to extend the partial safety concept towards designs at system level and to investigate how this affects the material consumption and the structural safety.