Xinhao He 교수

Abstract In this study, the effects of the degree of directionality on critical seismic performance assessment are investigated from two aspects: the bidirectional seismic demand represented by maximum‐direction spectrum and the performance indices obtained from nonlinear time‐history analysis. Firstly, typical representations of the bidirectional demand of ground motions are reviewed and compared, in seismic design practices (e.g., ASCE 7‐16, Eurocode8, and JRA). Statistical analysis using 83 g

After a disaster, ascertaining the operational state of extensive infrastructures and building clusters on a regional scale is critical for rapid decision-making and initial response. In this context, the use of remote sensing imagery has been acknowledged as a valuable adjunct to simulation model-based prediction methods. However, a key question arises: how to link these images to dependable assessment results, given their inherent limitations in incompleteness, suboptimal quality, and low reso

After a strong earthquake, it is crucial to evaluate accurately the health of structures in order to decide whether they can continue to be used. Isolation techniques are well known for enhancing the seismic performance of structures; however, a large response displacement anticipated in the design will likely impact the expansion joints. The occurrence of any damage or impact involves a large disturbance in the system or measurement equations. The Kalman filter (KF) is effective and reliable un

Abstract Rocking structures are recognized as an effective seismic response modification technique due to their peculiar dynamic characteristics. Meanwhile, in bridge structures, strong ground motions have frequently caused a rocking motion of pin bearings around their two toes, resulting in the pulling‐out of anchor bolts. This study, motivated by the promising features of rocking behaviors, seeks to develop a rocking isolation bearing system (RIBS) to control excessive response in bridges. An

The objective of this study is to examine the feasibility of estimating the parameters of various devices in seismic control systems and evaluating the maximum responses of the quantities of interest. The observability condition was applied to determine the sensor layout and modeling assumptions of the structure for the joint estimation problem and to eliminate unsuitable layouts. To estimate the parameters of multiple members at the isolation layer, including laminated rubber bearings, oil damp

Although the friction pendulum bearing system (FPS) has been widely used in the construction of buildings, bridges, and other structures to enhance their seismic performance, the FPS was adopted in bridge construction in Japan for the first time in 2020 on the Tokai-Hokuriku expressway. To validate the design hypotheses of the real bridge with FPS, a series of static and dynamic tests were performed, and the parameters of the FPSs were estimated. The girder of the bridge supported by four FPSs w

Abstract A bidirectional rocking isolation bearing system (Bi‐RIBS) is proposed to provide seismic protection for bridge structures. By using the 3‐D rocking motion of the Bi‐RIBS, this system acts as a mechanical fuse to limit the maximum force transmitted to the bridge piers and as a restoring component to control an excessive girder response. Possible applications in bridge structures were discussed. A simple analytical model was established to characterize the dynamics of an example bridge f

Abstract To manage structural responses under various external forces, the increasing incorporation of seismic isolation and supplementary damping systems in modern civil engineering necessitates post‐installation performance assessments. The challenge of accurately inferring system information from these complex dynamical structures, especially with limited sensor deployment, could be significant. From the perspective of solving inverse problems, this challenge hinges on constructing an input‐o

The uplifting slide shoe (UPSS) bearing, consisting of multiple sliding surfaces, is a new type of bearing which has been proposed to achieve reduced displacement under strong earthquakes without losing advantage of the slide bearing to deal with the thermal effects on bridges girders. In the present study, bi-directional implementation of the UPSS devices is proposed to achieve effectiveness in controlling the bi-directional seismic response of girder bridges induced by bi-directional ground mo

Reliable finite element (FE) models play a vital role in accurately predicting structural behaviors under various loading conditions in structural engineering applications. This paper presents a unified approach for solving time-domain and frequency-domain FE model updating problems. In this approach, both types of problems are formulated as stochastic dynamic systems with embedded parameter-to-data maps, enabling the estimation of unknown model parameters. The unscented Kalman filter (UKF) is e

ABSTRACT Seismic isolation techniques are widely used in regions susceptible to earthquakes. From a long‐term maintenance perspective, it is crucial to develop methodologies for assessing the post‐installation performance of these systems based on monitored data. Data assimilation techniques provide a versatile framework for addressing various challenges in complex environments by estimating the posterior distribution of unknown system states, enhanced by prior physical knowledge of systems. Thi

Abstract This study presents the experimental results on a scaled bridge model with a newly proposed unidirectional rocking isolation bearing system (referred to as Uni‐RIBS) on a shaking table. The bridge model features one superstructure girder and four bearings. The experimental input encompassed a variety of recorded, design, and harmonic ground motions, characterized by differing peak accelerations, with or without vertical components, and time‐scaled attributes. The superstructure girder's