Article
Engineering, Civil
Venkatesh Patnana, Durgesh C. Rai
Summary: Three different continuous plasterboard suspended ceiling systems were experimentally investigated. All the systems performed well up to floor accelerations ranging from 1.4 to 1.6 g without any visible damage. However, the system with free edges proved vulnerable at the natural frequency and suffered major damage. Thus, the vertical strut system with free edges is not suitable for multistory buildings in any seismic zone.
EARTHQUAKE SPECTRA
(2022)
Article
Construction & Building Technology
Kazutaka Shirai, Shuji Noro, Kenneth K. Walsh
Summary: This study introduces a passive negative stiffness device composed of curved leaf springs using geometric nonlinearity to mitigate the response of seismically excited structures. Experimental results demonstrate the device's effectiveness in reducing response acceleration within a certain range while ensuring structural stability.
STRUCTURAL CONTROL & HEALTH MONITORING
(2021)
Article
Engineering, Geological
Zhongguo Guan, Jianzhong Li, Hongya Qu
Summary: This article introduces a capable and resilient lateral isolation system (CRLIS) for transverse seismic isolation of long-span cable-stayed bridges. The effectiveness of the CRLIS is verified through experiments and numerical simulations, and a definition of the Rayleigh damping matrix is suggested.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Engineering, Civil
Gabriele Fiorentino, Cihan Cengiz, Flavia De Luca, George Mylonakis, Dimitris Karamitros, Matt Dietz, Luiza Dihoru, Davide Lavorato, Bruno Briseghella, Tatjana Isakovic, Christos Vrettos, Antonio Topa Gomes, Anastasios Sextos, Camillo Nuti
Summary: Integral abutment bridges (IABs) have attracted renewed interest due to their low cost, but there is limited knowledge on their dynamic behavior and vulnerability under seismic actions. Therefore, experimental tests were conducted to investigate the seismic behavior of IABs in depth.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2021)
Article
Engineering, Civil
Liangjie Qi, Masahiro Kurata, Jiantao Huang, Yohsuke Kawamata, Shinji Aida, Kosai Cho, Iori Kanao, Masashi Takaoka
Summary: This paper presents the seismic damage and its impact on functionality of continuous ceiling systems in a hospital specimen tested at the E-Defense shaking table. The results show that continuous ceiling systems are less prone to collapse compared to lay-in ceiling systems. However, the functional deterioration resulting from the damage needs to be addressed, particularly in key medical rooms with strict air environment requirements.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2023)
Article
Engineering, Geological
Marina E. Kalogerakou, Konstantinos A. Kapasakalis, Ioannis A. Antoniadis, Evangelos J. Sapountzakis
Summary: This article proposes a novel vertical Stiff dynamic absorber (SDA) that aims to minimize vertical accelerations induced on the structure and keep the displacement within reasonable limits. The optimized design parameters of the SDA are applicable across a wide range of vertical vibration control applications, achieving great acceleration isolation without compromising the weight-bearing capacity of the structure.
BULLETIN OF EARTHQUAKE ENGINEERING
(2023)
Article
Construction & Building Technology
Jianyang Xue, Pengchun Hu, Fengliang Zhang, Yan Zhuge
Summary: This study conducted shake table tests on brick cave dwellings to investigate their seismic performance, finding that the dynamic response and damage of the structural model significantly increased under seismic action, with substantial stiffness degradation. The main damaged areas were the piers, middle barrel vault, and Yaolian, with denser cracks at wall junctions.
JOURNAL OF BUILDING ENGINEERING
(2021)
Article
Engineering, Civil
Bonaventura Tagliafierro, Rosario Montuori, Maria Gabriella Castellano
Summary: This study evaluates the performance of a steel storage pallet racking system equipped with a novel seismic isolation system, which significantly reduces seismic effects on the racks. Real-time shake table tests demonstrate a great reduction in floor accelerations, with no uplift of base connections recorded. The most severe condition comes from a pulse-like record, emphasizing the importance of carefully considering displacement demands when defining isolator placement.
THIN-WALLED STRUCTURES
(2021)
Article
Engineering, Geological
Muhammad Zayed, Kyungtae Kim, Athul Prabhakaran, Ahmed Elgamal
Summary: Shake table testing was conducted to investigate the seismic response of a bucket foundation offshore wind turbine (OWT) system. The study focuses on the soil-structure interaction effects, particularly the excess pore pressure fluctuations and soil dilation excursions driven by induced cyclic strains. The experimental data is used to calibrate a numerical model, which is further extended to analyze the seismic response of a utility-scale OWT with and without wind loading effects. The research outcomes highlight the importance of excess pore pressure fluctuations, the exacerbating effect of wind loading on base rotation, and the need to model the turbine tower as a system of discrete masses.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Engineering, Mechanical
Hao Wang, Hui Gao, Jian Li, Zhihao Wang, Youhao Ni, Ruijun Liang
Summary: This study developed a new tuned inerter-negative-stiffness damper (TINSD) for seismic protection of structures, derived the closed-form design equation, and evaluated its mitigation performance and performance enhancement principle through comparisons. The results showed that the TINSD performs excellently in seismic protection and reducing the dynamic response of structures.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Engineering, Geological
A. F. Fayez, M. H. El Naggar, A. B. Cerato, A. Elgamal
Summary: This study presents and discusses the responses of single and grouped helical piles to strong ground motions during large-scale shake table testing, evaluating the effects of earthquake characteristics on their seismic performance. The study also delves into the interaction between piles within a group and the contributions of individual pile stiffness to the overall capacity of the pile group. Additionally, the impact of pile head connection to the pile cap on the pile group's response is evaluated and compared between fixed and pinned pile groups.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2022)
Article
Construction & Building Technology
Elizabeth Vintzileou, Charalambos Mouzakis, Lucia Karapitta, Androniki Miltiadou-Fezans
Summary: Architectural elements such as domes, vaults and arches are vulnerable to seismic actions due to the thrust they impose on vertical elements. Strengthening techniques suitable for monuments can improve the behavior of these structures and reduce damage.
Article
Engineering, Marine
Xiaowei Wang, Alice Alipour, Jingcheng Wang, Yu Shang, Aijun Ye
Summary: This study investigates the seismic resonance behavior of soil-pile-structure systems (SPSS) with scour effects through shake-table tests and numerical analyses. It is found that the resonance period generally increases with increasing scour depth and excitation intensity. The findings can be useful for the advanced seismic design of SPSS to mitigate the potential resonance behavior.
Article
Engineering, Civil
Su-Chan Jun, Cheol-Ho Lee, Chang-Jun Bae, Kyung-Joo Lee
Summary: In this study, the seismic performance of direct- and indirect-hung suspended ceilings was evaluated based on shake table tests. The key engineering parameters related to acceleration amplification and natural frequency were identified and the overall seismic performance was evaluated. Compared with the extensive failure observed in the lay-in panel ceiling specimens, marginal damage occurred around the pounded edge in the continuous panel ceiling specimens because of the robust restraining effects of the screw-attached panels on the ceiling grid members.
JOURNAL OF EARTHQUAKE ENGINEERING
(2022)
Article
Engineering, Civil
Xu Yan, Cui Cunyu, Zeng Zeng, Zeng Shijie
Summary: In cable-stayed bridge design, the ductility behavior of bridge towers is crucial for seismic response. Utilizing the strong strut-weak tower column design strategy can reduce residual displacement in severe earthquakes, yet it comes with increased construction costs.
EARTHQUAKE ENGINEERING AND ENGINEERING VIBRATION
(2021)
Article
Chemistry, Multidisciplinary
Kevin M. M. Wyss, John T. T. Li, Paul A. A. Advincula, Ksenia V. Bets, Weiyin Chen, Lucas Eddy, Karla J. J. Silva, Jacob L. L. Beckham, Jinhang Chen, Wei Meng, Bing Deng, Satish Nagarajaiah, Boris I. I. Yakobson, James M. M. Tour
Summary: A rapid and scalable method, using flash Joule heating (FJH), has been developed to produce graphitic 1D materials (F1DM) from polymers. By tuning the parameters, F1DM with controllable diameters and morphologies can be obtained, and hybrid materials with turbostratic graphene can also be synthesized. The F1DM outperform commercially available carbon nanotubes in nanocomposites. Compared to current synthetic strategies, FJH synthesis significantly reduces energy demand and global-warming potential, offering a cost-effective and sustainable route to convert waste plastic into valuable nanomaterials.
ADVANCED MATERIALS
(2023)
Article
Engineering, Civil
Debasish Jana, Satish Nagarajaiah
Summary: Full-field online sensing provides dense spatial information of vibrating structures in real-time. Computer vision-based technologies can capture dense responses, but long-term implementation of such techniques could be expensive and impractical. To address these problems, we propose a framework to estimate full-field vibration responses from a few sensors. This framework does not require any prior information on the structural model and shows excellent potential in health monitoring and control of various systems.
ENGINEERING STRUCTURES
(2023)
Article
Materials Science, Multidisciplinary
Paul A. Advincula, Wei Meng, Lucas J. Eddy, Jacob L. Beckham, Ivan R. Siqueira, Duy Xuan Luong, Weiyin Chen, Matteo Pasquali, Satish Nagarajaiah, James M. Tour
Summary: Graphene has been proven to be a valuable additive for composites, but its expensive synthesis has hindered its industrial application. However, a method called Flash Joule heating can rapidly synthesize graphene from coal materials like metallurgical coke. This study investigates the properties of graphene-epoxy composites with higher nanofiller content than previously reported. The results show that these composites exhibit improved mechanical properties and reduced environmental impact.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2023)
Article
Engineering, Mechanical
Sudheendra Herkal, Muhammad M. Rahman, Satish Nagarajaiah, Vijay Vedhan Jayanthi Harikrishnan, Pulickel Ajayan
Summary: Schwarzites are 3D solids with negative Gaussian curvatures that possess unique mechanical properties such as high ductility and strength. The energy dissipation mechanism of Schwarzites allows for the removal of energy from dynamic systems and reduction of system response. Experimental results show that Schwarzite geometry can increase the damping ratio by almost 80% with the same material volume as a solid support. Additionally, Schwarzites exhibit vibration isolation properties.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Chemistry, Analytical
Debasish Jana, Satish Nagarajaiah
Summary: In civil, mechanical, and aerospace structures, full-field measurement is necessary for precise damage estimation and control purposes. Conventional sensing methods require dense installation of contact-based sensors, which is impractical in real-life scenarios. This paper proposes a technique to accurately estimate the full-field responses of a structural system using a few randomly placed contact/non-contact sensors. The proposed method, based on compressive sensing, demonstrates significant potential in health monitoring and control of engineering systems.
Article
Engineering, Civil
Meng Wang, Fei-Fei Sun, Yuji Koetaka, Lin Chen, Satish Nagarajaiah, Xiu-Li Du
Summary: A purely frequency-independent negative stiffness damped outrigger (FI-NSDO) system is proposed in this paper, which combines frequency-independent damper (FID) and negative stiffness device (NSD). The FI-NSDO has the capability of simultaneously increasing the damping ratios of all target modes to their maximum values. Analysis in both frequency domain and time domain shows that the proposed FI-NSDO performs better in controlling the multi-mode vibration of seismic responses.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2023)
Article
Engineering, Civil
Yongkui Wen, Lin Chen, Satish Nagarajaiah
Summary: Damped outrigger is an effective approach for reducing dynamic responses of tall buildings. This study focuses on generalized damped outrigger (GDO) systems, which consist of a damper, a negative stiffness device and an inerter. By optimizing GDOs at different floors of the tall building, significant improvements in multimode damping effects can be achieved.
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(2023)
Article
Engineering, Mechanical
Sutanu Bhowmick, Satish Nagarajaiah, Anastasios Kyrillidis
Summary: Full-field discrete measurements of continuous spatiotemporal processes generate large datasets. Previous regression-based and deep learning-based methods fail to estimate higher-order PDE models in the presence of moderate noise. The proposed SNAPE method addresses these drawbacks by simultaneously fitting basis functions and estimating parameters of PDEs.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Engineering, Civil
Liangkun Wang, Ying Zhou, Satish Nagarajaiah, Weixing Shi
Summary: In this study, a bi-directional semi-active TMD with adaptive stiffness, variable mass, and semi-active damping is proposed to improve the seismic protection performance. The BSTMD can adapt to X and Y directional frequencies simultaneously and reduce the stroke of unidirectional STMD. Numerical results show that the BSTMD has a comparable control effect with less electromechanical devices.
ENGINEERING STRUCTURES
(2023)
Article
Engineering, Civil
Sutanu Bhowmick, Satish Nagarajaiah
Summary: The authors introduced a new method called SimultaNeous Basis Function Approximation and Parameter Estimation (SNAPE) to address the issues of previous methods in estimating the parameters of higher-order PDE models and dealing with noise. SNAPE fits basis functions to the measured response and simultaneously infers the parameters of the PDE model, demonstrating its applicability on various boundary conditions.
ENGINEERING STRUCTURES
(2023)
Article
Engineering, Civil
Meng Wang, Hai-Qiang Lu, Pi-Guang Wang, Satish Nagarajaiah, Xiu-Li Du
Summary: This paper proposes a novel amplifying damping transfer system (ADTS) as a solution for enhancing the damping of high-rise structures like wind turbines. The ADTS can transfer the upper rotation of the turbine tower to its bottom with a damping amplification mechanism, allowing for convenient and efficient installation of viscous dampers on wind turbines.
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(2023)
Article
Acoustics
Lin Chen, Zhanhang Liu, Yiqing Zou, Meng Wang, Satish Nagarajaiah, Feifei Sun, Limin Sun
Summary: The negative stiffness mechanism improves the damping performance of dampers on a stay cable. The study provides a practical negative stiffness device with adjustable negative stiffness and validates its effect through experiments. The device is combined with a viscoelastic damper in parallel or series for cable damping improvement.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Materials Science, Multidisciplinary
Paul Andrade Advincula, Wei Meng, Jacob L. Beckham, Satish Nagarajaiah, James M. Tour
Summary: CO2 emissions and waste plastic contribute greatly to environmental problems, and researchers are developing technologies for capturing, sequestrating, and utilizing CO2. Two methods, molten carbonate electrolysis and flash Joule heating, have shown promise in converting gaseous CO2 into solid carbon feedstocks and flash graphene. The combination of flash graphene and waste plastic as a reinforcing additive in composite applications can increase material properties and reduce CO2 emissions, water consumption, and energy consumption.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2023)
Article
Chemistry, Analytical
Debasish Jana, Satish Nagarajaiah
Summary: In the field of structural vibration response sensing, mobile sensors provide numerous benefits such as acquiring dense spatial information and not being limited to a specific structure. This study introduces a formation control framework for automatic multi-agent mobile sensing, which effectively controls the behavior of multi-agent systems for structural response sensing purposes. The proposed method leverages vibration data collected by these mobile sensors to estimate the full-field vibration response of structures, achieving high reconstruction accuracy.
Article
Chemistry, Analytical
Ashish Pal, Wei Meng, Satish Nagarajaiah
Summary: In this study, a Convolutional Neural Network (CNN) is developed to detect subsurface damage (SSD) using surface strain measurements. The trained network is capable of accurately detecting damage in different materials and can be used for subsurface crack detection and localization in real-life scenarios.
