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1. Global Sensitivity Analysis Framework for Vertical Load Path Resistance in Wood-Frame Residential Structures

   Rittelmeyer, Brandon M.; Roueche, David B. (October 2022, Proceedings of the 14th Americas Conference on Wind Engineering)

   This study presents a framework for global sensitivity analysis of wind uplift resistance in wood-frame residential structures. The vertical load path is modeled probabilistically as an assemblage of connections, with resistance distributions based on connection design capacity and cumulative dead load. An established sensitivity analysis approach is applied to the load path resistance model to evaluate the influence of the input parameter set on the system resistance, which is taken as the resistance of the weakest connection in series. A preliminary analysis illustrates the potential of the framework as a useful tool for assessing the relative importance of structural attributes for wind resistance, adaptable to any arbitrary vertical load path and parameter set. The framework also facilitates the evaluation of the relative vulnerability of different load path configurations from structure to structure. 

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2. Fragility-based sensitivity analysis framework for load paths subjected to wind hazards

   Rittelmeyer, Brandon M. Roueche (January 2023, 16th International Conference on Wind Engineering)

   A framework is presented for evaluating the sensitivity behavior of parameters in a structural load path with respect to wind hazard analytical fragilities. A preliminary analysis applies the framework to a vertical light wood-frame load path. A variance-based sensitivity analysis method is employed to compute first-order sensitivity indices of all input parameters on the basis of load path system resistance, fragility median, and fragility standard deviation. The results indicate that a sensitivity analysis predicated on fragility median provides a reasonable description of load path parameter influence and may serve as a useful complementary tool alongside traditional load path fragility approaches. The framework can be useful for identifying which fragility model parameters are most essential out of a broader suite of possible parameters, and for offering guidance to reconnaissance efforts for focusing on the most influential perishable data to capture following extreme hazard events. 

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3. Probabilistic wind uplift resistance framework for the relative evaluation of wood-frame load paths

   https://doi.org/10.1016/j.engstruct.2023.116984  

   Rittelmeyer, Brandon M; Roueche, David B (January 2024, Engineering Structures)

   Past failure risk analyses of wind-impacted wood-frame structural load paths have tended to consider simplified resistance models that account for a few key load path connections, in which connection capacity distributions are generally based on benchmark experimental results. However, recent post-storm reconnaissance studies have demonstrated that connections in the load path of light wood-frame structures are themselves composed of multiple elements with many configurations and possible failure modes. This study presents a flexible approach for modeling wind uplift resistance in wood-frame load paths that includes a more exhaustive set of potential failure points yet is computationally efficient and readily adaptable to various load paths composed of different assemblages of structural members and connections. In this framework, ultimate capacities of connections and wood members are either based on design equations provided in the National Design Specification for Wood Construction or another applicable standard or computed from a comparable mechanics-based model. Analytical capacity estimates for roof sheathing, roof-to-wall connections, and wall-to-slab-foundation connections accord well with the range of published experimental results for these connections. Capacities of connections that act in parallel are summed to transform the load path into an analogous load chain of series components. System-level wind uplift resistance, defined by the weakest component in series, is evaluated by Monte Carlo simulation. By providing a more complete description of resistance than previous simplified models have done while avoiding the expense of a detailed finite-element or other solid mechanics model, the method proposed here holds promise as a rapid, consistent, and accurate way to quantify wind resistance in any arbitrary wood-frame load path, with applications including insurance risk analysis, hybrid data science frameworks utilizing post-storm reconnaissance data, and estimation of hazard intensity from structural damage observations. 

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4. A Decommissioned Wind Blade as a Second-Life Construction Material for a Transmission Pole

   https://doi.org/10.3390/constrmater1020007  

   Alshannaq, Ammar A.; Bank, Lawrence C.; Scott, David W.; Gentry, Russell (September 2021, Construction Materials)

   null (Ed.)

   This paper demonstrates the concept of adaptive repurposing of a portion of a decommissioned Clipper C96 wind turbine blade as a pole in a power transmission line application. The current research program is aimed at creating a path towards sustainable repurposing of wind turbine blades after they are removed from service. The present work includes modelling and analysis of expected load cases as prescribed in ASCE 74 and NESC using simplified boundary conditions for tangent pole applications. Load cases involving extreme wind, concurrent ice and wind, extreme ice, differential ice, broken conductor, and broken shield have been analyzed and governing load cases for bending, shear, and torsion have been examined. Relative stiffnesses of different parts forming the wind blade’s cross section (i.e., shell, web, and spar cap) are determined. The corresponding stresses associated with each part under the governing loads are compared to allowable strength values which are determined from composite laminate theory and modelling of the known laminate structure of the E-Glass FRP material. Stresses and deflections obtained are compared with governing reliability-based design criteria and code requirements. The results of the structural analysis indicate that the wind blade can resist the expected loads with reasonable safety factors and that the expected deflections are within permissible limits. Recommendations are provided for detailing and modification of the wind blade for a power pole application in which crossarm and davit connections are highlighted, and foundation details are emphasized. 

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5. Experimental analysis of the response of open-ended pipe piles to static and cyclic axial loading using digital image correlation

   Fridman, Daniel G; Prezzi, M; Salgado, R (June 2025, Proceedings of ISFOG 2025)

   Offshore foundation elements are often subjected to cycles of compressive and tensile loading. Open-ended pipe piles are frequently used as foundations for wind turbines as monopiles or as part of jacket structures. This paper reports the results of two open-ended pipe pile tests in a half-cylindrical calibration chamber with image analysis capabilities. The model piles, with diameters of 44 mm and 63 mm, were jacked into dense silica sand samples, statically load tested in compression, cyclically load tested (under displacement-controlled conditions), and statically load tested in compression a second time. The cyclic load tests had 100 cycles with a half-amplitude of 1 mm. Digital images captured during testing were analysed using digital image correlation to obtain the displacement fields in the soil domain. Image analyses of compressive static load tests indicate that the soil plug undergoes vertical compression during static loading. Cyclic loading leads to shaft resistance degradation, which is correlated with contractive radial strains around the model pile. Cycling also causes vertical compression below the pile base and inside the soil plug, which increases the base resistance of the piles and ultimately increases the total compressive capacity of the model open-ended piles under static loading. 

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