Extreme wind load distributions for linear and nonlinear design

Journal of Wind Engineering and Industrial Aerodynamics

2013

a b s t r a c tIn current wind design practice, static wind loads are usually defined to obtain, by simple static analyses, the extreme values of any structural response that would be formally obtained with a strict dynamic buffeting analysis. The minimum and maximum values that may reach any response define the envelope. Equivalent static wind loads (ESWLs) allow to recover extreme responses in the envelope. As a first objective, this paper formalizes a general method to determine ESWL, in a nodal basis, by extending the concept of load-response correlation, which is only valid in the background range. The general method, the displacement-response correlation (DRC) method, covers the background and resonant contributions of the considered response. As a second objective, the paper addresses the problem of building a set of static wind loads that adequately reconstructs the envelopes of responses. The concept of principal static wind loads (PSWL) is introduced to form a reduced basis of representative loads well-suited for envelope reconstruction. Its optimality is demonstrated both analytically and with a detailed illustrative example.

Section: Introductionmentioning

confidence: 99%

Principal static wind loads

Journal of Wind Engineering and Industrial Aerodynamics

2013

“…In a non-Gaussian context, nothing prevents the use of the same formulation as (17) to determine the equivalent static wind load (Kasperski, 1992). Nothing guarantees, however, any boundedness of the overestimation of the envelope, which might in fact be rather severe (see examples).…”

Section: Assessment Of Extreme Value Overestimationsmentioning

confidence: 99%

“…In the following, we compare the overestimations resulting from the LRC ESWL (used as such even in the nonGaussian framework) and the bicubic-based CESWL. Notice that, in both cases, the envelope value condition is met; see (Kasperski, 1992) for the LRC approach; concerning the bicubic-based CESWL, this issue is solved with the rescaling (15).…”

Section: Assessment Of Extreme Value Overestimationsmentioning

confidence: 99%

Assessment of extreme value overestimations with equivalent static wind loads

Andrianne

Journal of Wind Engineering and Industrial Aerodynamics

2017

The wind-resistant design using equivalent static wind loads is convenient for structural engineers. This paper studies the reliability of such an approach in the case of non-Gaussianities in both aerodynamic pressures and responses. These non-Gaussianities are responsible for overestimations of envelope values and may result in uneconomical designs, if not appropriately understood, assessed and addressed. In this study, it is shown that the equivalent static wind loads defined with the Conditional Expected Load method, which extends the physical meaning of the Load-Response Correlation approach in a non-Gaussian framework, improves the issue of overestimations of envelope values. Several envelopes of structural responses are considered: the mean of extremes and the 86% quantiles of extremes, together with two reference periods (10 min and 1 h). Extensive wind tunnel measurements have been collected, which correspond to 371 h full scale. This study is undertaken for quasi-static analysis of structures and is illustrated with a low-rise building.

“…This technique has been mainly applied to lowrise buildings (Tamura et al, 1992(Tamura et al, , 2001. Following the same idea of a load associated with a maximum response, Kasperski (1992) established the LRC method giving an ESWL corresponding to an envelope value obtained by a linear quasi-static analysis in a Gaussian framework.…”

Section: Introductionmentioning

confidence: 99%

“…Conversely, the original gust loading factor and LRC methods and its extensions (Chen and Kareem, 2001) were developed assuming Gaussian processes. Actually, Kasperski (1992) sidesteps the extension to non-Gaussian processes arguing that, the LRC method would provide "[…] a very close approximation to the real load pattern […]" even if the aerodynamic pressure field was non-Gaussian or if the structure had a weakly nonlinear behavior. However, differences have been shown between the LRC-based ESWLs and those obtained with statistical treatment of wind-tunnel measurements (Tamura et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of the envelope of non-Gaussian structural responses with principal static wind loads

Canor

Journal of Wind Engineering and Industrial Aerodynamics

2016

a b s t r a c tIn current practice, structural engineers commonly focus on the wind-resistant design by means of static wind loads. In the case of non-Gaussianities, there is room for improvement to properly derive these static loads. First, this paper extends in a non-Gaussian context the concept of the load-response correlation (LRC) method establishing equivalent static wind loads (ESWLs). This is done by a proper recourse to the new concept of conditional expected static wind load and a proposed bicubic model for the joint and conditional distribution functions. Second, this paper investigates the envelope reconstruction problem targeting the efficient reconstruction of the envelope values of a set of non-Gaussian structural responses by means of principal static wind loads (PSWLs). They have been introduced in a Gaussian context and are obtained by a singular value decomposition of ESWLs. This paper addresses the extension of PSWLs to non-Gaussian structural responses, as well. The developments apply to structures with a linear behavior and subjected to an aerodynamic pressure field exhibiting mildly to strongly nonGaussian features. In this context, the well-known load-response correlation and conditional sampling methods are used for comparisons. This study is undertaken for quasi-static analysis of structures and is illustrated on a low-rise building.