Code Calibration in Wind Engineering: Shortcomings and Needs

The writing of the Second Generation Eurocode on wind actions on structures, prEN1991-1-4 has revealed a number of shortcomings. Well established as well as more recent action and response models are available, which have been incorporated into the new Code. Nevertheless, the issue remains of calibration, which affects not only the assessment of the characteristic value of the action given by EN1991-1-4, but also the code factors given by EN 1990. Among the parameters needed in a wind loading code, some are site-dependent, some are not. For site-dependent parameters, the task of code-writers is limited to the drafting of simple and clear rules for their derivation, so that no difference arises when the code is used in one country or another. As to site-independent parameters, the effort can be much bigger and should benefit from the exploitation of up-to-date research results, as well as from coordination among different communities of code-writers around the world. This paper tries to summarise what are the most urgent needs for calibration of wind loading codes, and how experimental research in Wind Engineering can help filling gaps.