• Earthquakes and Structures
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• v.25 no.5
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• pp.369-383
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• 2023

Seismic resilience (SR) plays a vital role in evaluating and improving performance losses along with saving repair costs of structures from potential earthquakes. To further explore the developments, hotspots, and trend directions of SR, a total of 901 articles are obtained from the Web of Science (WoS) database. CiteSpace software is used to conduct a bibliometric analysis, which indicates an upward trend of publications in SR and explores the relationship of countries, journals, cited references, and keywords based on visual maps and detailed tables. Then, based on the results of the bibliometric analysis, a state-of-the-art review is conducted to further explore the current challenges and trend directions of SR. The trend directions can be divided into five categories: (a) SR assessments of infrastructure structures, (b) multi-hazard quantifications of SR, (c) seismic resilient structures, (d) refining and calibrating analytical models, and (e) multi-criteria decision-making frameworks for sustainability and SR.

• Steel and Composite Structures
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• v.31 no.1
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• pp.1-12
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• 2019

Steel-concrete composite walls have been proposed and developed for applications in various types of structures. The double-skin profiled composite walls, as a natural development of composite flooring, provide structural and architectural merits. However, adequate intermediate fasteners between profiled steel plates and concrete core are required to fully mobilize the composite action and to improve the structural behavior of the wall. In this research, two new types of fasteners (i.e., threaded rods and vertical plates) were proposed and three specimens with different fastener types or fastener arrangements were tested under axial compression. The experimental results were evaluated in terms of failure modes, axial load versus axial displacement response, strength index, ductility index, and load-strain relationship. It was found that specimen with symmetrically arranged thread rods sustained more stable axial strain than that with staggered arranged threaded rods. Meanwhile, vertical plates are more suitable for practical use since they provide stronger confinement to profiled steel plate and effectively prevent the steel plate from early local buckling, which eventually enhance the composite action and increase the axial compressive capacity of the wall. The calculation methods were then proposed and good agreement was observed between the test results and the predicted results.

• Earthquakes and Structures
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• v.23 no.3
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• pp.315-328
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• 2022

Structures designed for wind have an opposite design approach to those designed for earthquakes. These structures are usually reliable if they are constructed in an area where there is almost no or less severe earthquake. However, as seismic activity is unpredictable and it can occur anytime and anywhere, the seismic safety of structures designed for wind must be assessed. Moreover, the design approaches of wind and earthquake systems are opposite where wind design considers higher stiffness but earthquake designs demand a more flexible structure. For this reason, a novel Machine learning framework is proposed that is used to assess and classify the seismic safety of the structures designed for wind load. Moreover, suitable criteria is defined for the design of wind resistance structures considering seismic behavior. Furthermore, the structural behavior as a result of dynamic interaction between superstructure and substructure during seismic events is also studied. The proposed framework achieved an accuracy of more than 90% for classification and prediction as well, when applied to new structures and unknown ground motions.

• Smart Structures and Systems
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• v.21 no.1
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• pp.75-97
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• 2018

In this paper, a novel higher-order shear deformation theory (HSDT) is proposed for the analysis of the hygro-thermo-mechanical behavior of functionally graded (FG) plates resting on elastic foundations. The developed model uses a novel kinematic by considering undetermined integral terms and only four variables are used in this model. The governing equations are deduced based on the principle of virtual work and the number of unknown functions involved is reduced to only four, which is less than the first shear deformation theory (FSDT) and others HSDTs. The Navier-type exact solutions for static analysis of simply supported FG plates subjected to hygro-thermo-mechanical loads are presented. The accuracy and efficiency of the present model is validated by comparing it with various available solutions in the literature. The influences of material properties, temperature, moisture, plate aspect ratio, side-to-thickness ratios and elastic coefficients parameters on deflections and stresses of FG plates are also investigated.

• Wind and Structures
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• v.36 no.1
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• pp.61-73
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• 2023

In this article, a novel structural modal parameters identification methodology is developed to determine the natural frequencies and damping ratios of civil structures based on the symplectic geometry mode decomposition (SGMD) approach. The SGMD approach is a new decomposition algorithm that can decompose the complex response signals with better decomposition performance and robustness. The novel method firstly decomposes the measured structural vibration response signals into individual mode components using the SGMD approach. The natural excitation technique (NExT) method is then used to obtain the free vibration response of each individual mode component. Finally, modal natural frequencies and damping ratios are identified using the direct interpolating (DI) method and a curve fitting function. The effectiveness of the proposed method is demonstrated based on numerical simulation and field measurement. The structural modal parameters are identified utilizing the simulated non-stationary responses of a frame structure and the field measured non-stationary responses of a supertall building during a typhoon. The results demonstrate that the developed method can identify the natural frequencies and damping ratios of civil structures efficiently and accurately.

• Steel and Composite Structures
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• v.35 no.3
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• pp.405-413
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• 2020

Current study on the buckling analysis of steel plate in composite structures normally focuses on applying finite element method to derive the buckling stress. However, it is time consuming, computationally complicated and tedious for general use in design by civil engineers. Therefore, in this study an analytical study is conducted to predict the buckling behavior of steel plates in composite structures. Hand calculation method was proposed based on energy principle. Novel buckling shapes with biquadratic functions along both loaded and unloaded direction were proposed to satisfy the boundary condition. Explicit solutions for predicting the critical local buckling stress of steel plate is obtained based on the Rayleigh-Ritz approach. The obtained results are compared with both experimental and numerical data. Good agreement has been achieved. Furthermore, the influences of key factors such as aspect ratio, width to thickness ratio, and elastic restraint stiffness on the local buckling performance are comprehensively discussed.

• Steel and Composite Structures
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• v.23 no.4
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• pp.435-444
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• 2017

In the past, the progressive collapse resulting from local failures during accidents has caused many tragedies and loss of life. Although long-span spatial grid structures are characterised by a high degree of static indeterminacy, the sudden failure of key members may lead to a catastrophic progressive collapse. For this reason, it is especially necessary to research the progressive collapse resistance capacity of long-span spatial grid structures. This paper presents an evaluation method of important members and a novel dynamic analysis method for simulating the progressive collapse of long-span spatial grid structures. Engineering cases were analysed to validate these proposed method. These proposed methods were eventually implemented in the progressive collapse analysis of the main stadium for the Universiade Sports Center. The roof of the structure was concluded to have good resistance against progressive collapse. The novel methods provide results close to practice and are especially suitable for the progressive collapse analysis of long-span spatial grid structures.

• Smart Structures and Systems
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• v.30 no.6
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• pp.639-648
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• 2022

This study aims at numerically and experimentally investigating torsional guided wave mixing with weak material nonlinearity under acoustoelastic effect in tubular structures. The acoustoelastic effect on single central frequency guided wave propagation in structures has been well-established. However, the acoustoelastic on guided wave mixing has not been fully explored. This study employs a three-dimensional (3D) finite element (FE) model to simulate the effect of stress on guided wave mixing in tubular structures. The nonlinear strain energy function and theory of incremental deformation are implemented in the 3D FE model to simulate the guided wave mixing with weak material nonlinearity under acoustoelastic effect. Experiments are carried out to measure the nonlinear features, such as combinational harmonics and second harmonics in related to different levels of applied stresses. The experimental results are compared with the 3D FE simulation. The results show that the generation combinational harmonic at sum frequency provides valuable stress information for tubular structures, and also useful for damage diagnosis. The findings of this study provide physical insights into the effect of applied stresses on the combinational harmonic generation due to wave mixing. The results are important for applying the guided wave mixing for in-situ monitoring of structures, which are subjected to different levels of loadings under operational condition.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.19 no.3
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• pp.14-22
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• 2023

Steel-pipe civil structures, including steel-pipe energy piles and cast-in-place piles (CIPs), utilize steel pipes as their primary reinforcements. These steel pipes facilitate the circulation of a working fluid through their annular crosssection, enabling heat exchange with the surrounding ground formation. In this study, the cooling performance of a ground source heat pump (GSHP) system that incorporated steel-pipe civil structures was investigated to assess their applicability. First of all, the thermal performance test was conducted with steel-pipe CIPs to evaluate the average heat exchange amount. Subsequently, a GSHP system was designed and implemented within an office container, considering the various types of steel-pipe civil structures. During the performance evaluation tests, parameters such as the coefficient of performance (COP) and entering water temperature (EWT) were closely monitored. The outcomes indicated an average COP of 3.74 for the GSHP system and the EWT remained relatively stable throughout the tests. Consequently, the GSPH system demonstrated its capability to consistently provide a sufficient heat source, even during periods of high cooling thermal demand, by utilzing the steel-pipe civil structures.

• Earthquakes and Structures
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• v.18 no.5
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• pp.567-580
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• 2020

In this paper, irregularly designed planar reinforced concrete wall structures are investigated computationally. For this purpose, structures consisting of four regular and irregular models of short-order (two-class) and intermediate (five-class) types have been investigated. The probabilistic evaluation of seismic damage of these structures has been performed by using the incremental inelastic dynamic analysis to produce the seismic fragility curve at different levels of damage. The fragility curves are based on two classes of maximum damage indices and the Jeong-Nansha three-dimensional damage index. It was found that there is a significant increase in damage probability in irregular structures compared to regular ones. The rate of increase was higher in moderate and extensive damage levels. Also, the amount of damage calculated using the two damage indices shows that the Jeong-Nensha three-dimensional damage index in these types of structures provides superior results.