Data-driven structural health monitoring (SHM) is an approach which relies on the information contained in the data and through signal analysis techniques captures the features, variations, and uncertainties that data contain. This paper presents the response of shaking table tests of a full-scale, 3-story building with sliding slabs connected by horizontal buckling-restrained braces for energy dissipation. First, the global dynamic characteristics of the structure were identified from a series of the building response data under different intensity level of base excitations. The variation of the identified modal parameters, such as the mode frequencies and modal shapes, was discovered. The influence of sliding slabs on the dynamic characteristics of the frame was also investigated through the measured response and the equation of motion with six degree of freedom systems. Comparison on the achieved interstory stiffness due to the implementation of sliding slabs and the fixed (locked up) slab was examined. The mechanism and dynamic characteristics of sliding slabs, including energy dissipation of the friction force, BRB hysteresis behavior, and unintended damping force during strong base excitation were analyzed directly using the ARX/recursive model. The extracted unintended damping force performed like a friction hysteretic response, which needs to be considered for frame modeling in shaking table tests. The findings through the data analysis have clarified the important aspects of sliding slabs and demonstrated the benefits and applicability of sliding slabs on reducing the frame response.

A new methodology is proposed for developing a scenario-based site-specific response spectrum (RS) considering near-fault effects in Taiwan. First, source parameters, together with reference rock site conditions, are defined according to the available geological and geophysical information at a target site close to a potential active fault in northern Taiwan. Secondly, the scenario-based response spectrum for a reference rock site condition is developed theoretically through an empirical approach by using a ground motion prediction equation (GMPE). The effect of the pulse period and the occurrence probability of near-fault pulse-like ground motion on RS is evaluated by using the ground motion simulation (GMS) technique, in which the stochastic finite-fault simulation method is validated and applied for evaluating velocity pulse. Third, site-specific site amplification is incorporated into RS through a site transfer function calculated from the measured horizontal-to-vertical Fourier spectral ratio through the microtremor (MHVR) of the target site. Finally, the design spectrum of the target site is compared with the derived site-specific RS to evaluate the impact of the neighbor fault on the structure of the target site.

The width-thickness requirement for highly ductile built-up box columns in AISC 341-22 is conservative when comparing the hysteretic responses of highly ductile box columns and I-shaped columns. This study aimed to assess the seismic performance of moderately ductile box columns in a 3-story steel dual frame with a buckling-restrained braced frame (BRBF) and a special moment frame (SMF). The frame specimen was configured in phase 1 testing to allow the slabs to slide relative to the steel frame; Teflon pads were provided between the slabs and steel beams, and horizontal buckling-restrained braces (BRBs) were installed between the slabs and steel beams. In phase 2, the horizontal BRBs were replaced by rigid links such that the frame specimen simulated a conventional construction. Two phases with 17 shake table tests were conducted on the frame specimen. A near-fault motion record, obtained from the 2022 Chihshang earthquake, was used as an input motion. In phase 1, test results showed that the slab sliding system was effective in reducing the floor acceleration by 25% when compared to the rigid slab frame system. In phase 2, the base of moderately ductile built-up box columns still performed well without local buckling even when the interstory drift angle reached 0.045 rad. Postearthquake tests were conducted on the all-steel, first-story BRB that was removed from the building specimen after all shake table tests. A higher-mode buckling of the core plate was observed at both ends of the core, causing a minor strength increase at the end of the test.

Estimating the story drift directly from acceleration records is challenging. This paper presents a systematic integration scheme involving the empirical mode decomposition of signals to estimate the earthquake-induced displacement of buildings, including their permanent deformation after an earthquake. A three-phase algorithm is proposed. In phase-1, the displacement waveform without residual displacement is estimated, then in phase-2 the residual deformation is calculated. Combining both phase-1 and phase-2, the displacement waveform is estimated. Three types of acceleration data, namely, shaking table test data, seismic response data for a building, and near-fault ground motion data, were used to validate the proposed method.

Structural health monitoring is conducted to ensure the structural integrity of a building during earthquakes. This study aimed to improve our understanding of the dynamic response of buildings subjected to a series of earthquake excitations, focusing on interpreting structural dynamic characteristics and identifying potential seismic damage subjected to a series of earthquake excitations. To this end, a series of seismic response data of a 13-story reinforced-concrete/steel building were collected through long-term monitoring over 2 years. A systematic approach for monitoring the health of the building was established by integrating several algorithms for vibration-based (both output-only and input-output parametric nonparametric feature-discrimination algorithms) and model-based feature extraction techniques. Furthermore, the time-varying dynamic characteristics of the building were determined, including its modal frequency, mode shape, and stiffness, as extracted from features obtained over the monitoring period of 2 years. Safety assessment of this newly compound high-rise building is investigated to explore the system dynamic characteristics through long-term seismic monitoring.

In this study, a probabilistic seismic hazard analysis (PSHA) using a traditional approach with a simple logic tree that handles a single-site sigma is developed to present a site-specific ground motion hazard. The analysis relies on the accelerometer data collected from the I-Lan Plain, a deep sedimentary basin in Northeastern Taiwan where hundreds of earthquake sequences (with Mw = 4.0-7.6) were recorded by the Taiwan Strong Motion Instrument Program (TSMIP) network between 1992 and 2016. The performance of PSHA on soil and hard sites is evaluated from two representative instrumented sites (ILA048 and ILA025), using residual measures available from a ground motion model (GMM) developed by Phung et al. [2023] (referred to as Ph23), from which the uncertainties in site terms (delta S2Ss) and single-site sigma (sigma SS,S) are estimated. We address key conceptual issues in the current PSHA approach and introduce a new region- and site-specific PSHA approach in which (1) site-to-site variability (phi S2S) is estimated as a random variance in a mixed effects GMM regression and (2) the GMM site-specific single-site sigma (sigma SS,S) is replaced with a generic site-corrected aleatory variability (sigma 0). Comparison of the region- and site-specific hazard curves from our method against the traditional method estimates at two well-recorded sites in the I-Lan region shows an approximate 50% difference in prediction ground motion values considering for 2% and 10% probability of exceedance in 50 years.

A new velocity model (GMM) compatible with a ground motion prediction model (GMM) for Taiwan is presented in this study. The model is developed using the data set extracted from the flatfile compiled for Taiwan Senior Seismic Hazard Analysis Committee (SSHAC) level 3 project (NCREE, 2015). The Phung et al. (2020) ergodic Sa GMM was used as a backbone model for estimating the site amplification in the frequency domain using inverse Random vibration theory (IRVT). The main motivation for developing a velocity model is that the estimation of the site scaling in terms of the time-averaged shear-wave velocity over the top 30 m (VS30), the method also provides the corresponding depth-dependent VS(z) profiles and the value for the selected VS30 value as a result of the inverse quarter-wave-length method (IQWL). Not all of the empirical amplification can be explained by the 1-D VS profiles andvalues. For soft sites (VS30 < 500 m/s), and intermediate periods (0.5-2.0 sec), there is additional amplification in the empirical data which is attributed to 3-D path and site effects. Using the proposed method, the resulting GMM provides a VS profile, k, and 3-D effect for each VS30 value, which provides a more informative handoff of ground-motion information for use in site-specific site response studies.

To discern the diagnostic accuracy between the updated diagnostic consensus of the Asian Working Group for Sarcopenia (AWGS) in 2019 (AWGS 2019) and the previous AWGS 2014 guidelines. A prospective population-based cohort study. The study included 731 older community-dwelling adults aged ≥ 65 years who participated in face-to-face interviews and were followed up for 11-year mortality until 31 Mar 2022. We utilized a handgrip strength dynamometer to measure participants’ muscle strength, while their walking speed was determined by a timed 6-meter walk test at their usual pace. Additionally, muscle mass was measured using dual-energy X-ray absorptiometry scanning. Sarcopenia was defined as the presence of low muscle mass in combination with weakness and/or slowness both by AWGS 2014 and 2019 criteria. The present study followed 731 participants (mean age 73.4 ± 5.4 years, men predominant 52.8

Structural health monitoring (SHM) has been related to damage identification with either operational loads or other environmental loading playing a significant complimentary role in terms of structural safety. In this study, a non-parametric method of time frequency analysis on the measurement is used to address the time-frequency representation for modal parameter estimation and system damage identification of structure. The method employs the wavelet decomposition of dynamic data by using the modified complex Morlet wavelet with variable central frequency (MCMW+VCF). Through detail discussion on the selection of model parameter in wavelet analysis, the method is applied to study the dynamic response of both steel structure and reinforced concrete frame under white noise excitation as well as earthquake excitation from shaking table test. Application of the method to building earthquake response measurement is also examined. It is shown that by using the spectrogram generated from MCMW+VCF method, with suitable selected model parameter, one can clearly identify the time-varying modal frequency of the reinforced concrete structure under earthquake excitation. Discussions on the advantages and disadvantages of the method through field experiments are also presented.

The measurement of vital signs (such as respiration rate, body temperature, pulse, and blood pressure), especially during strenuous activities, is essential for physical performance and health monitoring. A variety of wearable chest band sensors have been developed, commercialized, and widely used in consumer and healthcare settings. The plethora of technology choices also means that each unique chest band sensor may require different data acquisition hardware and software systems, and data may not be transferable between platforms. Therefore, the objective of this work was to develop a low-cost, disposable, respiration sensor that could be attached onto any elastic chest band. The approach was to spray-coat graphene nanosheet (GNS)-based thin films onto unidirectionally stretchable elastic fabric to form a piezoresistive material. Snap buttons were incorporated at the ends of the fabric so that they could be attached onto any chest band, removed at any time, and replaced for a new data collection event. The resistive nature of the nanocomposite sensor means that they can be easily interfaced (e.g., using a voltage divider) with any existing data acquisition (DAQ) module while adding respiration monitoring capabilities. To facilitate testing of these nanocomposite respiration sensors, a miniature DAQ module with four sensing channels was also prototyped. Then, tests were performed with human subjects wearing a nanocomposite chest band and a reference commercial respiration monitoring chest band. Simultaneous measurements of subject respiration verified the respiration monitoring performance of these low-cost, disposable, nanocomposite fabric sensors.

We develop a ground motion prediction equation (GMPE) for estimating the vertical ground motion amplitudes for crustal earthquakes in Taiwan. The data set used for the development includes strong-motion recordings mainly from Taiwan earthquakes (M3.5–7.6) and supplemented with large-magnitude earthquakes (M6.5–7.9) from other regions in the Pacific Earthquake Engineering Research Center (PEER) next generation attenuation (NGA)-West2 database. The functional form of the GMPE is similar to that of Phung et al. developed for the horizontal component (P20). The GMPE provides median and standard deviations of peak ground acceleration (PGA) and 5% damped pseudo spectral acceleration response ordinates of the orientation-independent average horizontal component of ground motion (RotD50) for the spectral period of 0.01–10 s. The vertical ground motion developed in this study can be paired with the P20 horizontal component model to estimate a vertical-to-horizontal (V/H) ratio that is unbiased. In the vertical component, we observe significant nonlinear site effects in the period of about 0.2–0.5 s, moderate nonlinear site effects in the period of about 0.01–0.04 s, and small nonlinear site effects in the period of about 0.05–0.075 s. Compared to our horizontal GMPE, anelastic attenuation is faster, VS30-scaling is reduced, and nonlinear site response is weaker for the vertical component.

Inter-story drift or roof drift plays an important role in the damage assessment of building structures. Hence, three performance levels regarding drift limits for reinforced concrete (RC) structures and steel structures are addressed in the seismic rehabilitation prestandard of the Federal Emergency Management Agency (FEMA 356). However, directly measuring the structural displacement is very difficult in most field applications and, alternatively, accelerometers are generally deployed to collect the structural responses instead of using displacement meters for building seismic monitoring. During the past decade, different techniques have been developed to provide displacement estimation using acceleration measurements but the conventional integration scheme relies on baseline correction methods to have a reasonable result and none of these techniques can properly estimate the residual displacement. In this study, the techniques of singular spectrum analysis (SSA) and the integration scheme are combined to estimate the displacement directly from the recorded acceleration. In the proposed method, SSA decomposes the acceleration measurement into approximation and detailed parts; the approximation parts are used as weighting factors, and the detailed parts are integrated twice to have the temporary displacements. Then, the displacement waveform can be correctly reproduced by fusing these two parts. Moreover, the proposed method is verified by using the roof responses of the RC specimen recorded during the shaking table test. The displacement waveform is correctly estimated as well as the induced permanent deformation during earthquake excitation. Last of all, a conclusion is briefly drawn and the applicability of the proposed method to building seismic monitoring is described.

This study presents the monitoring and assessment technology of a large arch dam, the Fei-Tsui arch dam in Taiwan, from both seismic response data and ambient vibration measurement collected from a wireless sensing system. Subspace identification (considering inputs) and stochastic subspace identification (output-only) are both used to extract the dynamic characteristics of the dam. Variation of the system natural frequencies of the dam with respect to reservoir water level is investigated. The system transfer function between the earthquake input and the response of the dam body is also investigated using the ARX model. By combining ambient vibration survey, seismic response data, and static monitoring, the safety assessment of the dam structure can be made.

The precision tools equipped with active vibration isolation platform in high-tech facilities are sensitive to low-frequency vibration. Currently, there are neither standards nor rules to select the time period of vibration data for conducting the spectral analysis of low-frequency vibration, and none of the analyses can be used to compare and discuss the differences of spectral amplitude generated by the selection of different time periods. Therefore, to estimate the amplitude of low-frequency vibration, the spectral analysis at low-frequency range is crucial. This paper is to elaborate the spectral analysis procedures on various band widths by using zero-padding on the vibration signal in low-frequency band. The mechanism not only facilitates to obtain more reliable result but also to lay a common base for comparison from different user. Finally, the in situ measurement data, including high-speed train-induced low-frequency vibration, are used to exemplify the length of time period affects the results of spectral analysis, either on narrowband or one-third octave band analysis.

Story and roof drift ratios play a key role in the assessment of the structural damage of a building if structural displacement can be measured or calculated. In general, for building seismic monitoring, accelerometers are used to compile the responses for analysis instead of using displacement meters because they are more cost effective. Therefore, an accurate estimate of the displacement response of a building using acceleration measurements will be helpful for the rapid assessment of the damage to its structure after an earthquake. In this study, the combination of an algorithm with singular spectrum analysis (SSA) and an integration scheme is proposed to estimate structural displacement directly from acceleration measurements. The SSA was conducted with varying sizes of the data trajectory matrix, using the approximation part as a weighting factor and the detailed part to integrate for the temporary displacement, to obtain a final weighted temporary displacement. The proposed algorithm was verified using the shaking table test data for four large-scale reinforced concrete frames. Through the proposed method, both the displacement waveform and the induced residual displacement after earthquake excitations can be estimated. The application of the proposed algorithm to building seismic response data is also discussed.

The paper addresses results of an international effort in further developing a novel friction damper device for a reduction of induced vibrations in structures. A description of the device, results of small-scale experiments, and results of full-scale shaking table tests are presented. The result of the investigations shows that the effectiveness of the device is determined not only by the friction material but also by the location as well as the way of its installation. The devices have a stable energy dissipating behaviour. They are flexible in their application, since they only need limited space. The device can be installed easily and readjusted after installation. The damping capacity of the device can be increased by simply adding friction layers. The friction damper device proves to be an efficient and economical device for a reduction of dynamic response of structures.

A ground motion prediction equation (GMPE) is presented for computing the median and standard deviation of peak ground acceleration (PGA) and 5% damped pseudo-spectral acceleration (PSA) for periods between 0.01 s and 5.0 s for probabilistic seismic hazard analysis (PSHA) and engineering applications in Taiwan. An integrated strong motion dataset consisting of two subduction earthquake regions was selected from 3314 recordings from Taiwan with M 4.5 to M 7.1 and 3376 recordings from Japan with M 6.5 to M 9.1. This dataset was then used to validate, and refit where necessary, the function form provided by Abrahamson et al. for application to Taiwan subduction earthquakes. The proposed model accounts for the extrapolation behaviors associated with the large-magnitude scaling and the near-source scaling terms, both of which were developed empirically by using the combined Taiwan–Japan dataset. The distance attenuation and site term were developed specifically for the Taiwan region. The site term is based on two parameters; the time-averaged shear wave velocity of the top 30 m depth ( V S 30 ) and the depth-to-the-shear wave velocity horizon of 1.0 km/s ( Z 1.0 ).

Active control strategies are more powerful and attractive than passive and semi-active control strategies. An active control device, namely active mass damper (AMD), consists of mass, a guideway, and an AC-driven motor and can provide a widely applicable range of control forces with a very limited power requirement. This device can be more effective to suppress earthquake-or wind-induced vibrations to civil structures. Various innovative control algorithms have been developed to drive AMD against seismic loads, and these new or improved algorithms are also found as a key element in smart structure technology. Some research on active control strategies for the reduction of the seismic responses uses either full-state or, at least, velocity feedback; however, the accurate measurement of the displacement and velocity is typically unavailable from real-world structures. Instead, the control algorithms based on acceleration feedback are more feasible for the practical implementation of control system. In this study, an active control system is developed by integrating an AC-driven AMD and accelerometers. This system is comprised of a real-time embedded system with a control algorithm which executes the sliding mode control (SMC) with acceleration feedback. The acceleration feedback SMC controller is designed in accordance with an identified model of a model building. Subsequently, this control system is experimentally implemented and verified using shake table testing. Performance of the integrated system as well as the responses of the frame are evaluated and discussed to demonstrate the effectiveness of the acceleration feedback SMC algorithm in mitigating vibrations of seismically-excited structures.

The overarching goal of this research is to derive innovative methodologies for analyzing diverse sensing streams to yield actionable information that directly support post-earthquake response, emergency management, and disaster recovery. As a step towards this goal, the objective of this study is to use data collected from the California Strong Motion Instrumentation Program (CSMIP) to demonstrate that a particular class of system identification (SI) techniques – namely, subspace identification (SI) or recursive subspace identification (RSI) – is especially suitable for rapid, post-disaster, structural health assessment. The advantage of SI/RSI is that it is an input-output and data-driven method, where only structural response records (e.g., acceleration records) are needed for extracting dynamic properties of the structure. In this paper, both SI and RSI were be applied to assess CSMIP-instrumented buildings with acceleration records from past ground motion events. The result verified that building dynamic characteristics (i.e., natural frequencies and mode shapes) could be clearly identified using all the recorded data simultaneously. In addition, the RSI algorithm was also employed for analyzing data recorded from the Northridge earthquake event. Time-varying modal properties of the building were also examined.