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1
Content available Resonance of a structure with soil elastic waves released in non-linear hysteretic soil upon unloading
Kowalczyk Piotr
Studia Geotechnica et Mechanica
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2022
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Vol. 44, nr 4
253--266
EN
High-frequency motion is often observed in small-scale experimental works carried out in flexible containers under simplified seismic loading conditions when single harmonic sine input motions are introduced at the base of a soil specimen. The source of the high-frequency motion has often been sought in experimental inaccuracies. On the other hand, the most recent numerical studies suggested that high-frequency motion in the steady-state dynamic response of soil subjected to harmonic excitation can also be generated as a result of soil elastic waves released in non-linear hysteretic soil upon unloading. This work presents an example of a finite element numerical study on seismic soil–structure interaction representative of an experimental setup from the past. The results show how high-frequency motion generated in soil in the steady-state response, apparently representative of soil elastic waves, affects the steady-state response of a structure, that is, it is presented how the structure in the analysed case resonates with the soil elastic waves. The numerical findings are verified against the benchmark experimental example to indicate similar patterns in the dynamic response of the structure.
2
Content available remote Piecewise exact solution of the seismic energy balance equation and its verification by shake table tests
Güllü Ahmet, Yüksel Ercan
Archives of Civil and Mechanical Engineering
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2022
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Vol. 22, no. 3
art. no. e112
EN
The seismic energy-based design concept is attracting increasing attention due to its known advantages such as counting for frequency content of earthquake and duration-related cumulative damage. The concept requires the solution of a relatively complex integration namely the energy balance equation. Thus, some researchers have preferred to use equivalent parameters (e.g. spectral velocity) and prediction equations for the determination of seismic energy. In this study, a piecewise integration technique is proposed to achieve the exact solution of the energy balance equation. The proposed algorithm was validated through shake table tests conducted on the single degree of freedom (SDOF) and multi-degree of freedom (MDOF) systems in elastic and inelastic ranges, as well as analyses of the nonlinear response history of a benchmark frame. To evaluate the efficiency of the proposed solution technique, two MDOF specimens were supplemented by metallic dampers to have discrete damping properties. The seismic energy responses of all specimens with and without metallic dampers were determined satisfactorily. A maximum relative difference of 15% was obtained between the algorithm and the results of the experimental and numerical examples used for the validation.
3
Content available Evaluation of steel frame structures with the response of seismic isolators
Beykzade Mohammad, Baghchesaraei Alireza, Baghchesaraei Omid Reza
Civil and Environmental Engineering Reports
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2020
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Vol. 30, no. 3
23--47
EN
As science keeps evolving over time, new solutions are being put forward for reducing structural damage. One such solution is the use of seismic isolation systems. Seismic isolation systems reduce the response of structures to the force of earthquakes by reducing the input (force) acceleration when the natural period of the structure increases. Therefore, the use of seismic isolation systems is recommended in the analysis of diverse structures. This study was carried out on seismically isolated buildings with 8, 10, and 12 regular steel floors, modeled by a non-linear isolator in two-, or three-second periods. The differences in data and the responses of the buildings were compared with fixedbase buildings with 8, 10, and 12 floors.
4
Content available remote Development of a new hexagonal honeycomb steel damper
Javanmardi Ahad, Ghaedi Khaled, Ibrahim Zainah, Huang Fuyun, Xu Pu
Archives of Civil and Mechanical Engineering
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2020
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Vol. 20, no. 2
490--508
EN
This paper presents a new metallic damper called hexagonal honeycomb steel damper (HHSD) for damage mitigation in structures subjected to earthquake excitations. The HHSD is composed of steel plates having several hexagonal and welded to the top and bottom anchor plates. The damper takes the advantages of hexagonal honeycomb geometry and steel material capability to dissipate seismic energy. The quasi-static cyclic test was performed experimentally and numerically on a series of specimens to evaluate the robustness of the HHSD. A three-dimensional finite element analysis of HHSD was carried out and verified with the experimental results. The results showed that the HHSD has low yield displacement, stable hysteretic behavior, a good range of ductility and high-energy dissipation capability. Additionally, the constitutive formulas of the damper are also derived based on the obtained results. Furthermore, it is found to have lightweight and inexpensive with ease of implementation as a potential alternative for new structures or seismic retrofitting of the existing structures.
5
Content available remote Seismicity evaluation of Mongton area of Salween in Myanmar
Lian Chao, Kong Yuyang, Chen Xinqiang, Qiao Yueqiang
Acta Geophysica
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2019
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Vol. 67, no. 3
765--773
EN
The area of Mongton is located in the central part of main stream of Salween. There has a straight-line distance of 200 km to the border of China’s Yunnan Province and 90 km to the border of Chiang Mai Province of Thailand. There are two earthquake concentrating regions of destructive earthquakes within this area. It reflects the collision between the Indian plate and the Eurasian plate. The main regional seismic activity characteristics are summarized as follows in accordance with the spatial-temporal distribution characteristics of the seismic activity and the estimated future seismic trend of the area under analysis: (1) There are 132 times of destructive earthquake occurrences of M ≥ 4.7 that occurred ever since the record within this area. There are 2915 modern small earthquakes of 4.6 ≥ M ≥ 2.0 being recorded within this area totally since 1966. (2) Orientation of axis P of the maximum principal compressive stress of the regional focal mechanism solutions is mainly distributed in the angular domain in the direction of NNE–NE–NEE and under the horizontal action, which indicates that the distribution of the tectonic stress fields within the area is very complicated with the spreading of the earthquake fracture planes displaying a characteristic multi-directionality. (3) This area is located at the intersection of the Himalayan Seismic Belt and the Southwestern Yunnan Seismic Belt; the seismic activities involved display an obvious alternate quiescence and active phenomenon. It will experience a strong seismic activity level similar to that of the previous 100 years in the future 100 years. Large earthquakes are likely to occur within this area.
6
Content available remote Neural network aided stochastic computations and earthquake engineering
Lagaros N. D., Papadrakakis M., Fragiadakis M., Stefanou G., Tsompanakis Y.
Computer Assisted Mechanics and Engineering Sciences
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2007
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Vol. 14, No. 2
251-275
EN
This article presents recent developments in the field of stochastic finite element analysis of structures and earthquake engineering aided by neural computations. The incorporation of Neural Networks (NN) in this type of problems is crucial since it leads to substantial reduction of the excessive computational cost. In particular, a hybrid method is presented for the simulation of homogeneous non-Gaussian stochastic fields with prescribed target marginal distribution and spectral density function. The presented method constitutes an efficient blending of the Deodatis-Micaletti method with a NN based function approximation. Earthquake-resistant design of structures using Probabilistic Safety Analysis (PSA) is an emerging field in structural engineering. It is investigated the efficiency of soft computing methods when incorporated into the solution of computationally intensive earthquake engineering problems.
7
Content available remote Modele matematyczne w analizie pracy konstrukcji na przykładzie skończonego elementu gruntowego
Czarniawski T.
Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo
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2002
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Z. 9 (154)
13-18
8
Content available remote Modele matematyczne w analizie nieliniowego zachowania się konstrukcji
Czarniawski T.
Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo
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2002
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Z. 9 (154)
19-23
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