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E. Lourens

24 records found

Identification of structural properties of high-rise buildings

Application of a model updating technique for estimating the structural properties of high-rise buildings

This research focused on applying vibration-based model updating to estimate the structural properties of high-rise buildings using a discrete Timoshenko beam model. Previous studies by Moretti et al. [1] and Taciroglu et al. [2] showed limitations in estimating the structural pr ...
This research contributes to a novel non-contact installation method for offshore wind turbines, utilizing electromagnetism for positional control. Floating wind installation requires efficient control methods for payload positioning. Current methods use tuggerlines that are phys ...

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 a ...
This thesis aims to investigate the feasibility of developing a successful unsupervised Structural Health Monitoring (SHM) methodology to detect damage in structures, specifically bridges. Detecting damage, especially in its earliest stages, is challenging, thus prompting the nee ...

Wave Induced Dynamics of Offshore Heavy Lift Cranes on Jack-Ups

Analysis of the annual probability of failure of the crane in normal operation

Due to the increasing size of offshore wind turbines, the jack-up vessels and cranes installing them need to increase in size. The increase in length of the crane boom results in an increase of the dynamic response of the crane. This increase in response results in higher loads i ...
Regular maintenance of civil engineering structures is essential for their safety. Current maintenance regimes involve periodic inspections at regular time intervals. In the time between inspections, there can be a critical development in the structural integrity of a structure, ...
The offshore wind energy industry is quite literally reaching for the sky to meet the increasing demand for renewable energy in Europe. Offshore wind turbines are sprouting out of the waves off the coast of many European nations and their size is increasing rapidly. As the turbi ...
With the highly increased interest in offshore wind turbines and their technologies, the sector has witnessed rapid development in the past decade. For installed offshore wind turbines, there has been a lot of research conducted in the field of aero-, hydro- and structural dynami ...
The Haringvlietbrug, which was delivered in 1964 and connects the island of Goeree-Overflakkee to the Dutch mainland, approaches the end of its lifetime. Rijkswaterstaat and Witteveen+Bos investigate the potential use of vibration-based structural health monitoring (SHM) to track ...

Operational Modal Analysis on a Tied-Arch Railway Bridge

A case study to determine the natural frequencies and mode shapes from in-situ accelerational measurements

Due to increasingly efficient engineering of the last decades, the design process for civil structures is heading in the direction of optimal solutions. Among other things, the reduction in self-weight enhances the susceptibility to dynamic loads. As the process for the determina ...
Wind turbines are typically designed for an operational life of 20-25 years. The operation of the assets can be extended beyond their design life if structural components have sufficient reserves left. One approach is to monitor fatigue loads and compare these with design assumpt ...
Technology improvements and growing maturity of the offshore wind industry have resulted in significant cost reductions and rise in demand. More can be achieved by focusing on improving the understanding of key design areas of an offshore wind turbine (OWT). Since fatigue is one ...

Over the last decade, the demand for offshore power cables has increased significantly due to, in particularly, the emergence of offshore wind. Despite this growth, industry-wide rules and guidelines to analyse fatigue during cable installation operations are ...

In the Netherlands there are many bridges that crosses waterways, which are key nodes in the transportation system. The safety and integrity of these bridges is nowadays assessed by (visual) inspections at regular intervals. This approach cannot provide information about damage d ...
The offshore wind industry has grown rapidly over the last decade and drivetrains are increasing in size to reduce the cost of energy. These turbines are operating in a harsh environment. Adopting a preventive maintenance strategy is important to achieve an as high as possible av ...
Fatigue is often a governing design factor for offshore wind turbines. Since the design of offshore wind turbines includes conservatism, the actual accumulated fatigue damage can be lower than what the turbine is designed for. In this case, the operator can make a decision on lif ...
Over 450 oil platforms need to be removed from the North Sea in the next decade. Each of these platforms is custom designed for installation and service lifetime, but not for decommissioning. Allseas' Pioneering Spirit is the largest heavy lift vessel in the world, capable of lif ...
Vibration-based structural health monitoring of civil engineering structures is receiving increasing attention in recent years. This is due to the development of more robust system identification techniques as well as improvements with regard to the practicality of installing the ...