bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical behavior of ship to shore container crane subjected to different stochastic wind actions.
Authors: Solazzi L , Zrnić N 
Published: June 2024

Abstract
This research aims to evaluate and compare the mechanical behaviour of a real crane subjected to wind actions. These are schematized in three different ways, i.e. considering wind velocity variable in time (two models) and the second one considering constant in time (as defined in the standards for designing the cranes). The fluctuation was estimated by adopting two power spectral models: Eurocode and the IEC Kaimal turbulence mode. The wind velocity and the resulting forces were determined by developing a specific Mathcad program. Through a crane solid model, it was possible to make a finite element model and then perform the numerical analyses by Ansys software. The elaboration of the numerical results shows, especially in terms of maximum displacement, that the two spectral models show very similar results, which are greater concerning the one obtained considering constant velocity; the displacement increment is approximately of three times. The research was extended also to the crane supports reaction. By adopting a variable wind action, the constraint reaction also takes on negative magnitudes, demonstrating the real possibility of crane overturning. The research is still under development especially to assess whether the results are extendable by adopting other wind turbulence models.
Comparative study of experimental assessment methodologies for the dynamic characterization of elastic elements
Authors: Liravi Hassan , Arcos Robert , Clot Arnau , Conto Kenny F. 
Published: June 2024

Abstract
In this paper, four distinct methods for the experimental assessment of the dynamic stiffness of elastic elements in a laboratory environment are compared. The comparison has been done experimentally in a simple mass-element-mass-isolator test rig based on the proposals presented in ISO 10846 by testing an elastomeric mat specimen. The four existing experimental approaches compared are the direct and indirect methods proposed by ISO 10846, a frequency-independent characterization method based on the transmissibility peak, and an existing methodology for in situ applications that in this work has been proposed to be used for laboratory assessments. In order to compare these methodologies, the vertical stiffness of the under-ballast mat sample has been obtained through the four methods proposed. The application of the approach also showed that the rotational degrees of freedom test rig massive elements must be considered in the characterization of elastic elements using this particular test rig configuration, especially when their rotational stiffness is low. Results show that the in situ method applied to laboratory-based setups allows for obtaining accurate results for a wide range of frequencies with a simple experimental setup.
Regression-based Evaluation of Novel Intensity Measures under Alternative Ground Motion Record Sets
Authors: Kadas K , Yakut A 
Published: June 2024

Abstract
Intensity measures are generally considered as the fundamental properties of strong ground motion records and are widely utilized in performance-based seismic design methodology to relate the seismic hazard levels to the structural damages, or seismic response in general. Recent two decades have exhibited several studies proposing new alternatives that have intended to reduce the variability in seismic demand predictions. Although there exist several simple-to-advanced scalar and vector ground motion intensity measures; the literature is limited in the number of comparative studies investigating the efficiency of these parameters, especially in the entire response range of structures. This study aims at evaluating the correlation of major engineering demand parameters with novel simple-to-advanced intensity parameters following a regression-based approach to calculate efficiency metrics. For a group of low-to relatively high-rise reinforced concrete frames, alternative ground motion record sets have been formed considering different simple scalar intensity measures including peak ground acceleration, peak ground velocity, acceleration spectrum intensity, velocity spectrum intensity and spectral acceleration at the fundamental period of the structure of consideration, and utilizing these record sets, nonlinear time history analyses have been performed using OpenSees software to obtain key engineering demand parameters of the multi-degree-of-freedom systems. The correlation performance of novel scalar and vector intensity parameters have been quantified by evaluating regression models formed in between demand parameters and intensity measures. The regression-based approach has assisted to rank the ground motion intensity parameters according to their efficiency in terms of reducing the variability in response. The results of this comprehensive study display the relative correlation performance of scalar and vector forms together and mark particular scalar parameters as ‘best candidates’ for reliable loss estimation studies, despite their simplicity.
Sensitivity Analysis of the Seismic Response of Steel Moment Frames Under Different Earthquake Scenarios
Authors: Torres-Rodas Pablo , Fayaz Jawad , Medalla-Riquelme Miguel 
Published: June 2024

Abstract
This research examines the influence of the two main types of earthquake mechanisms (i.e., subduction and crustal) on the seismic response of steel moment frames (SMFs). Nonlinear time history analyses are conducted on five archetype SMFs using two suites of selected unscaled recorded ground motions. The first suite consists of records from subduction earthquakes, while the second suite consists of unscaled crustal ground motions that are spectrally equivalent to the subduction ground motion suite. The differences between the two seismic environments are analyzed by conducting a sensitivity analysis of the seismic response of the SMFs against ground motion intensity measures. The results indicate that peak floor accelerations and inter-story drift ratios under subduction earthquakes are statistically higher than their counterparts from crustal earthquakes. On average, peak floor accelerations and inter-story drifts of the SMFs are amplified by 1.43 and 1.13, respectively, when subjected to ground motions from subduction sources.
In-situ characterization of Soil Structure Interaction through measurement of Impedance Functions
Authors: Clément J , Lancieri M , Bouhjiti D , Semblat J F , Richard B 
Published: June 2024

Abstract
In situ characterization of structural behaviour under seismic hazard provides an opportunity to acquire experimental data that improve our understanding of soil-structure interaction (SSI). Experimental programs such as Lotung and Hualien in Taiwan, EuroProteas in Greece and NUPEC in Japan, are amongst the most known. Such investigations aim at studying a structure with a rigid shallow raft and measuring the seismic impedance functions at soil-foundation interface. Indeed, impedance functions are by far the most widely used tools to study SSI. In this paper, considering feedbacks from these in situ tests, we aim at assessing the feasibility to acquire measurements of the seismic impedance functions for any structure with a rigid shallow foundation. To test the proposed methodology, we carry out a laboratory test with a small-scale device: the soil is represented by a model material (silicon rubber block) and the foundation by a cylindrical shaker inducing monitored harmonic vertical forces on the silicon rubber block. Experimental tests are paired with numerical simulations to identify, by inverse analysis, unknown parameters and to compute the order of magnitude of displacements and forces within the system. This paper presents the laboratory test setup, the experimental design, and the results of the associated simulations.
Model of coordinated crowd dynamics
Authors: Racic V. , Gazzola F. 
Published: June 2024

Abstract
This paper presents a mathematical model of synchronisation of multiple people during cyclic activities such as walking, running, jumping and bouncing. Providing that quality models of individual loading for these activities do exist, the sync model is the key component towards an urgently needed yet reliable model of artificial dynamic loading due to multiple active occupants. A model proposed here describes the effect of external and internal factors on the crowd dynamics. The former includes periodic external stimuli on the body motion of individuals, such as perceptible vibration of the ground and music beats. The later addresses the mutual interaction between individuals, such as possibility to see, hear or touch each other. Modelling approach is inspired by the existing models of coupled pendulums while the governing equations feature Mathieu-type behaviour. For the sake of simplicity and efficiency, the model is kept linear and deterministic. All modelling parameters have a physical interpretation and their values can be calibrated to match experimental measurements.
Dimensioning and realistic design of a novel based negative stiffness seismic isolator
Authors: Florakis Georgios I. , Kapasakalis Konstantinos A. , Antoniadis Ioannis A. , Sapountzakis Evangelos J. 
Published: June 2024

Abstract
Seismic isolation, which at first used only for special applications, is nowadays gaining increased popularity in the field of protecting existing structures from seismic loading and it even constitutes one of the standard methods for seismic upgrade. This method can be achieved with various devices, with elastomeric bearings being the most commonly used. The main drawback of these devices is that they permit large horizontal displacements in every direction. An effective approach to mitigate these responses under earthquake events is an advanced negative stiffness damped system, termed as KDamper, which its dynamic performance has been demonstrated in recent studies. In this paper, an extension of the initial device, the Extended KDamper (or EKD), is presented. The structural form and its negative stiffness mechanism are introduced with special emphasis placed on its dimensioning and its indicative design. More specifically, for a reference SDOF system with a mass of 1tn, the components of the EKD are realistically designed and a detailed assembly of the device is presented. The final model proves that the proposed device is realistic and within reasonable technological capabilities. To verify and evaluate the feasibility of this device, a numerical case study is also conducted on the SDOF system subjected to 30 artificial accelerograms. The results and the comparison with conventional and high damped elastomeric isolators demonstrate that the Extended KDamper can reduce both structural displacements and accelerations, proving its effectiveness and superiority over the other isolation techniques.
System identification based appraisal of soil structure interaction in elevated water tank for various reservoir conditions
Authors: Gautam Dipendra , Rimal Hariram , Olafsson Simon , Rupakhety Rajesh 
Published: June 2024

Abstract
Due to the lack of information regarding structural details and construction technology, finite element analysis based results may be dubious for aging structures. The results will not confirm the effect of soil structure interaction either since back analysis based assumptions may not exactly represent the behavior of soil and structure accurately. To this end, realistic material properties as well as dynamic characteristics are required for a reliable numerical model. This study reports the dynamic characteristics of a 50-year-old pre-code overhead water tank constructed with smooth bars. Ambient vibration records were taken for empty, half, and full reservoir conditions. Parametric identification using the numerical algorithm for subspace state space system identification (N4SID) is performed to estimate the modal properties of the 14.43 m tall water tank. The fundamental vibration frequencies of the tank for empty, half, and full reservoir conditions are estimated as 1.1 Hz, 0.93 Hz, and 0.77 Hz, respectively. We also created the numerical model of the tank with and without soil structure interaction. The fixed base analysis resulted in the fundamental vibration frequencies of 1.21 Hz, 1.02 Hz, and 0.86 Hz, respectively for empty, half, and full reservoir conditions. Similarly, the fundamental vibration frequencies are estimated as 1.08 Hz, 0.91 Hz, and 0.78 Hz, respectively for empty, half, and full reservoir conditions when soil flexibility is considered. The results highlight that system identification-based fundamental vibration frequencies are better captured by the model created incorporating soil flexibility. We conclude that soil structure interaction is vital to be considered for special structures such as water tanks in active seismic regions with loose soil deposits.
SHM approach with indirect load measurements and Kalman update of state and model parameters
Authors: Kähler Philipp , Petryna Yuri 
Published: June 2024

Abstract
The present contribution is dedicated to the development of advanced approaches for structural health monitoring (SHM) of civil engineering structures. The approach consists of two principal parts, a continuous load monitoring system (LMS) and a continuous state and condition monitoring system based on Kalman Filter update. The overall approach can serve as a kind of Digital Twin for SHM. The measurement data assimilation with a physically based structural model by use of Kalman Filters can provide reliable state predictions if the actual load history is known. To overcome this problem, the present work proposes a two-step update procedure. The first step contains a cluster of Convolutional Neural Networks for the traffic load identification, including its magnitude, mixture, position and velocity. The obtained numerical results show a very good correlation between predicted and reference data. In the second step the identified loads are used as input for the Kalman Filter updates. The results of a second numerical example show that the model parameters like stiffness, damping and mass can be continuously predicted even in presence of sudden changes and permanent uncertainties.
Reusable Miniature Piezo-Magnetic Sensor for Rapid Application of Electro-Mechanical Impedance Technique on Steel Structures
Authors: Gupta Ashok , Aulakh Dattar Singh , Rawat Divya Singh , Bhalla Suresh 
Published: June 2024

Abstract
In the last two decades, the electro-mechanical impedance (EMI) approach has been established as an effective technique for structural health monitoring (SHM) of civil structures. When employed in the EMI technique, piezo sensors exhibit extremely high sensitivity towards structural damage. However, the instrumentation of piezo sensors to a structure requires permanent bonding, which increases the complexity and possibility of deterioration over time. Additionally, large structures require numerous sensors, which disturb the monitoring economics. This demands an urgent development of reusable piezo sensors for an economical and effective monitoring setup. Accordingly, this paper focuses on developing magnetic reusable piezo sensors for damage monitoring using the EMI technique. In this study, three variants of the advanced reusable piezo sensor using a magnet is fabricated and investigated for damage detection and localisation on the steel plate specimen. The repeatability of all the piezo-magnetic sensors is evaluated by estimating the coefficient of correlation. Root mean square deviation (RMSD) is estimated between the healthy and damaged states to locate the damage. All the variants of piezo magnetic sensor are effectively able to capture the damage with good sensitivity.
Structural mitigation measures to archaeological wooden Viking age sledges based on calibrated FEM models using advanced vibration measurements
Authors: Ellingsen Ståle , Hauer David , Carioti Mattia , Kosche Florian , Vedholm Kjetil , Brekke Arild , Gjestvang Morten 
Published: June 2024

Abstract
The Viking Ship Museum in Oslo, Norway, houses the world’s largest collections of artefacts from the Viking era and holds the best-preserved Viking ships in the world. It is being expanded to provide new exhibition areas, improving both the visitor experience and the physical conditions for the objects on display. Three extremely fragile alum treated sledges are secured onsite as they are considered too fragile to move off the premisses. Finite element models are developed as a tool for understanding the sledges’ static and dynamic behaviour and the models are used to design effective mitigation measures applied to the sledges’ existing support systems. The models are established using highly detailed geometry 3D scans. They are dynamically calibrated using advanced vibration measurements identifying the sledges’ eigenfrequencies with corresponding mode shapes. The models are also calibrated using load deformation measurements with controlled loads applied to the sledges’ support systems.
Effects of wind-induced vibrations in tall buildings on cognitive work performance, comfort, and wellbeing of the occupants
Authors: Heshmati K , Shahabpoor E , Darby A , Walker I , Ghanbari S 
Published: June 2024

Abstract
Tall buildings inherently have low natural frequencies, excitable by wind loading through buffeting and vortex shedding. Such vibrations can cause discomfort or even fear in the occupants which is a design failure from vibration serviceability standpoint. Current wind-induced vibration serviceability guidelines such as ISO10137-2007, have proposed their acceptability criteria based on human perception of vibrations. However, recent studies suggest that such perception thresholds may not be an appropriate measure of vibration acceptability. Rather, more direct factors such as influence on work (both cognitive and physical) performance, health and wellbeing, and the emergence of mild motion sickness (sopite syndrome), should be used to assess ‘acceptability’.
This study provides experimental evidence of the effects of wind-induced vibrations on cognitive work performance, comfort, and wellbeing of the occupants. The state-of-the-art motion simulator facility, located at the University of Bath (VSimulator) was used to simulate bidirectional random vibrations, typical of tall building response due to wind loading. Under fully controlled conditions, research participants were exposed to six different motion conditions, as a cross-product of two frequencies and three peak accelerations, five of which were deemed acceptable for office buildings according to ISO-10137. Both objective and subjective psychological measurements were carried out to evaluate work performance, comfort, and wellbeing of participants subjected to these different motion characteristics. The results showed that both peak acceleration and frequency of motion had adverse effects on work performance, comfort and wellbeing of participants and showed evidence of the onset of sopite syndrome symptoms during even relatively short (∼2 hour) exposures. It was concluded that even for motion conditions with peak acceleration magnitudes below the threshold of conscious perception, there were negative consequences, especially as exposure to such motions caused participants to experience sopite syndrome. The data here suggests that buildings constructed to current standards might lead to negative consequences for wellbeing and work performance even when people are not consciously aware of any motion. Current serviceability criteria might be insufficient to address acceptable levels of wind-induced vibrations in tall buildings and future design criteria could be based on how vibrations affect health, wellbeing and performance rather than simply on the perceptibility of vibrations.
Retrofitting of typical existing school buildings through seismic vulnerability assessment
Authors: Tabernero Rodrigo , Ambrosini Daniel , Curadelli Oscar 
Published: June 2024

Abstract
Extensive damage to school buildings has been observed around the world during past earthquakes and their potential vulnerability and seismic retrofit alternatives need to be assessed. In regions of moderate and high seismic risk, there is a probability of structural damage and even collapse of school buildings, resulting in the loss of life of hundreds of children. In this work, seismic performance of standardized existing school buildings, lacking proper seismic design, is assessed by means of a numerical study. A 3D nonlinear finite element model is developed, and failure analyses are performed using a set of 10 seismic records scaled at increasing values of peak ground acceleration (PGA). Four seismic retrofit alternatives are proposed and evaluated following two major design approaches, stiffening and flexibilization. For each considered case, seismic fragility curves are derived, and seismic risk is assessed as limit state probability in 50 years, considering PGA as a random variable. Results obtained from this work allow the identification of the contribution of each proposed alternative to the reduction of seismic risk of the school buildings. A very simple and low-cost alternative, such as flexibilization by decoupling the facades from the lower floors, was found to produce excellent results.
A study on the effects of torsional spillover on an ideally controlled three dimensional structure
Authors: Abhishek S , Pilakkat Deepthi , Chakraborty Sanjukta 
Published: June 2024

Abstract
In this study, the adverse effect of an inadequately designed input control force was experimentally investigated in view of the excitation of the torsional modes of a structural system. The initial formulation was developed based on a generalized symmetric structural system under PD, PI, and PID control strategies that aimed at controlling the lateral modes of the structural system. Based on the control design, an experimental investigation was carried out on a single-story symmetric frame structure under the three designed control conditions using an Arduino-based data acquisition system. The structure was subjected to sinusoidal excitation with different frequency ratios and white noise excitation. In the next step, the system was perturbed by reducing the column stiffness in a way, that made the center of mass and the center of stiffness different. The perturbed structural system was also provided with the same initially designed input control forces under the same set of external excitations. Responses of the different control algorithms were recorded and analyzed considering the excitation of the torsional mode of the perturbed system. A significant excitation of the torsional mode was noticed in the study, particularly for an excitation near the resonating frequency of the lateral mode of the system.
Magnetic Control of a Simple Pendulum with a Moving Pivot Point
Authors: Atzampou Panagiota , Meijers Peter , Tsouvalas Apostolos , Metrikine Andrei 
Published: June 2024

Abstract
The present study introduces a magnetic PD control technique for the case of a simple pendulum driven by a sinusoidal motion of its pivot. The results attained demonstrate a good control performance for all the excitation cases of pivot point motion considered. The motion of the mass of the pendulum is successfully attenuated even when the pivot excitation is at the natural frequency of the pendulum. Furthermore, a fixed desired position can be achieved with small error and no saturation of the actuation present at steady-state. The initial distance between the magnet and the mass that ensures an efficient motion control is derived analytically and is validated by numerical simulations. The magnetic control method proposed serves as promising foundation for a non-contact position control technique for offshore wind turbine installation purposes.