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C.D. Rijna
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1
Estimating Period Lengthening of High-Rise Buildings
Application of vibration-based FE model updating on a small-scale steel tower structure for period lengthening estimation
This thesis investigates the estimation of period lengthening (T˜/T) in structures using model updating, which assesses frequency shifts due to changes in boundary conditions, such as flexible bases. A 2D finite element (FE) model based on Timoshenko beam elements was developed and optimized through Sequential Least Squares Quadratic Programming (SLSQP) to align simulated dynamics with measured natural frequencies and mode shapes of a steel structure.
The research was divided into two phases. Phase one utilized synthetic modal data to validate the model updating process in an error-free environment, showing that the algorithm effectively resolves stiffness-to-mass ratios rather than individual properties. Period lengthening predictions proved more accurate and stable with stiff springs, while soft springs demonstrated higher sensitivity and discrepancy. Phase two applied real measurement data, yielding results consistent with synthetic data but revealing a “plateau” in the cost function, where optimal parameter determination was challenging due to model and measurement uncertainties.
The findings indicate that model updating is a feasible method for estimating period lengthening, especially for flexible foundations. However, results are sensitive to modeling and measurement uncertainties, necessitating careful evaluation to ensure optimization convergence and parameter precision. The study recommends further research to mitigate uncertainties and enhance the method’s applicability in high-rise building design. ...
The research was divided into two phases. Phase one utilized synthetic modal data to validate the model updating process in an error-free environment, showing that the algorithm effectively resolves stiffness-to-mass ratios rather than individual properties. Period lengthening predictions proved more accurate and stable with stiff springs, while soft springs demonstrated higher sensitivity and discrepancy. Phase two applied real measurement data, yielding results consistent with synthetic data but revealing a “plateau” in the cost function, where optimal parameter determination was challenging due to model and measurement uncertainties.
The findings indicate that model updating is a feasible method for estimating period lengthening, especially for flexible foundations. However, results are sensitive to modeling and measurement uncertainties, necessitating careful evaluation to ensure optimization convergence and parameter precision. The study recommends further research to mitigate uncertainties and enhance the method’s applicability in high-rise building design. ...
This thesis investigates the estimation of period lengthening (T˜/T) in structures using model updating, which assesses frequency shifts due to changes in boundary conditions, such as flexible bases. A 2D finite element (FE) model based on Timoshenko beam elements was developed and optimized through Sequential Least Squares Quadratic Programming (SLSQP) to align simulated dynamics with measured natural frequencies and mode shapes of a steel structure.
The research was divided into two phases. Phase one utilized synthetic modal data to validate the model updating process in an error-free environment, showing that the algorithm effectively resolves stiffness-to-mass ratios rather than individual properties. Period lengthening predictions proved more accurate and stable with stiff springs, while soft springs demonstrated higher sensitivity and discrepancy. Phase two applied real measurement data, yielding results consistent with synthetic data but revealing a “plateau” in the cost function, where optimal parameter determination was challenging due to model and measurement uncertainties.
The findings indicate that model updating is a feasible method for estimating period lengthening, especially for flexible foundations. However, results are sensitive to modeling and measurement uncertainties, necessitating careful evaluation to ensure optimization convergence and parameter precision. The study recommends further research to mitigate uncertainties and enhance the method’s applicability in high-rise building design.
The research was divided into two phases. Phase one utilized synthetic modal data to validate the model updating process in an error-free environment, showing that the algorithm effectively resolves stiffness-to-mass ratios rather than individual properties. Period lengthening predictions proved more accurate and stable with stiff springs, while soft springs demonstrated higher sensitivity and discrepancy. Phase two applied real measurement data, yielding results consistent with synthetic data but revealing a “plateau” in the cost function, where optimal parameter determination was challenging due to model and measurement uncertainties.
The findings indicate that model updating is a feasible method for estimating period lengthening, especially for flexible foundations. However, results are sensitive to modeling and measurement uncertainties, necessitating careful evaluation to ensure optimization convergence and parameter precision. The study recommends further research to mitigate uncertainties and enhance the method’s applicability in high-rise building design.
Preliminary design of a marina in San Antonio Este
For recreational and touristic uses, and a nautical connection with San Antonio Oeste
Student report
(2023)
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F. Middeldorp, C.D. Rijna, J.M. Nooy van der Kolff, R.K. Vos, L.E. Kluft, J.R. Moll, P.W.C. Chan, P. Arecco
This design report presents the outcomes of a multidisciplinary project undertaken by a team with diverse backgrounds in civil engineering. The project focuses on a preliminary design for a new marina in San Antonio Este, Argentina, with the purpose of serving as a recreational spot and a terminal for a nautical connection to San Antonio Oeste. Recreational activities include whale watching and swimming with sea lions. Sustainability is a key guiding principle, aiming to blend the marina with the natural environment and add value to the region. The report starts with an introduction outlining the project’s background, goals, and scope, followed by a detailed methodology for the design process. The area study section highlights the environmental and hydrometeorological conditions of the project location, emphasizing the challenges posed by a significant tidal range. It also discusses the choice of a water bus stop location in San Antonio Oeste and provides recommendations for further data collection and development. The design stage presents the chosen preliminary design, detailing the pier, floating pontoon, gangway, mooring field, and boat ramp. Finally, the need is noted for more precise data, environmental assessments, and geotechnical investigations to improve the design.
...
This design report presents the outcomes of a multidisciplinary project undertaken by a team with diverse backgrounds in civil engineering. The project focuses on a preliminary design for a new marina in San Antonio Este, Argentina, with the purpose of serving as a recreational spot and a terminal for a nautical connection to San Antonio Oeste. Recreational activities include whale watching and swimming with sea lions. Sustainability is a key guiding principle, aiming to blend the marina with the natural environment and add value to the region. The report starts with an introduction outlining the project’s background, goals, and scope, followed by a detailed methodology for the design process. The area study section highlights the environmental and hydrometeorological conditions of the project location, emphasizing the challenges posed by a significant tidal range. It also discusses the choice of a water bus stop location in San Antonio Oeste and provides recommendations for further data collection and development. The design stage presents the chosen preliminary design, detailing the pier, floating pontoon, gangway, mooring field, and boat ramp. Finally, the need is noted for more precise data, environmental assessments, and geotechnical investigations to improve the design.