Shaking table test on seismic responses of a wind turbine tower subjected to pulse-type near-field ground motions

The shaking table tests of a 1:7 scale model of three-floor steel frame base-isolated building was completed to study the seismic responses of base-isolated buildings under near-fault ground motions. Under the action of the typical near-fault seismic wave, the seismic responses of base-isolated structures increase with the increase of PGA. The maximum story displacements of super-structure decrease with increase of story. The velocity pulse has an adverse effect to acceleration responses of base-isolated structures. The isolation effect of base-isolated super-structures is still favorable under near-fault ground motions, but it will be necessary to add damping in isolation system or limit the displacement of bearings to prevent the excessive deformation of isolation layer.

Download Full-text

Collapse analysis of a wind turbine tower with initial-imperfection subjected to near-field ground motions

Structures ◽

10.1016/j.istruc.2020.11.019 ◽

2021 ◽

Vol 29 ◽

pp. 373-382

Author(s):

Yazhou Xu ◽

Qianqian Ren ◽

Hui Zhang ◽

Wenhao Shi

Keyword(s):

Wind Turbine ◽

Ground Motions ◽

Near Field ◽

Initial Imperfection ◽

Wind Turbine Tower ◽

Collapse Analysis

Download Full-text

Seismic Response of Container Crane under Near-Field and Far-Field Ground Motions

Applied Sciences ◽

10.3390/app11041740 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1740

Author(s):

Van Bac Nguyen ◽

Jungwon Huh ◽

Bismark Kofi Meisuh ◽

Jongwoo Kim ◽

Inn-Joon Park

Keyword(s):

Seismic Response ◽

Shaking Table Test ◽

Ground Motions ◽

Near Field ◽

Bending Moment ◽

Shaking Table ◽

Far Field ◽

Container Crane ◽

National University ◽

Geometric Length

In this study, the seismic response of a container crane under near-field and far-field ground motions was investigated using a shaking table test on a 1/20 scale crane. The 1/20 scale crane was designed and fabricated based on the similitude laws, in which three independent quantities: geometric length, acceleration, and elastic modulus, were used to design the 1/20 scale crane. A series of shaking table tests were conducted at the Seismic Research and Test Center, Pusan National University, Yangsan Campus to evaluate the seismic response of the scale crane under near-field and far-field ground motions. The results show that the near-field ground motions can cause larger internal forces (that is, axial force and two bending moments) in the landside and seaside legs and larger portal drift than the far-field ground motions. The portal drift of the container crane subjected to the near-field ground motions was 43% higher than that of the container crane subjected to the far-field ground motions. Furthermore, when subjected to the near-field ground motion, the bending moment in the crane’s portal leg was 37% higher than the bending moment when the crane was subjected to the far-field ground motions.

Download Full-text

Seismic performance analysis of a wind turbine tower subjected to earthquake and ice actions

PLoS ONE ◽

10.1371/journal.pone.0247557 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0247557

Author(s):

Shuai Huang ◽

Yuejun Lyu ◽

Liwei Xiu ◽

Haijun Sha

Keyword(s):

Sea Ice ◽

Wind Turbine ◽

Seismic Performance ◽

Shear Force ◽

Shaking Table Test ◽

Bending Moment ◽

Shaking Table ◽

Seismic Behaviour ◽

Wind Turbine Tower ◽

Calculated Model

Sea ice is one of the main loads acting on a wind turbine tower in areas prone to icing, and this threatens safe working life of the wind turbine tower. In our study, a simplified calculated model of ice, wind turbine tower, and water dynamic interaction under earthquake action was proposed, which could avoid to solve a large number of nonlinear equations. Then, the seismic behaviour of the wind turbine tower with and without the influence of sea ice was investigated, and we found that the influence of the greater mass of the sea ice on the seismic response of a wind turbine tower should be considered when the wind turbine tower is designed in an area with thick ice. With the influence of the most unfavourable ice mass, the deformation and energy dissipation capacity of the wind turbine tower are decreased, and the wall thickness or stiffening rib thickness should be increased to improve the seismic performance and ductility of the wind turbine tower; the shear force and bending moment increased significantly on the wind turbine tower, and the shear force changes at the bottom of the wind turbine tower and position of action of the sea ice: attention should be paid to the wind turbine tower design at these positions. Finally, we conducted the shaking table test, and verified the rationality of our proposed simplified model.

Download Full-text

Seismic response analysis of steel–concrete hybrid wind turbine tower

Journal of Vibration and Control ◽

10.1177/10775463211007592 ◽

2021 ◽

pp. 107754632110075

Author(s):

Junling Chen ◽

Jinwei Li ◽

Dawei Wang ◽

Youquan Feng

Keyword(s):

Wind Turbine ◽

Response Spectrum ◽

Ground Motions ◽

Time History ◽

Seismic Action ◽

Response Spectrum Method ◽

Spectrum Method ◽

Wind Turbine Tower ◽

Ground Types ◽

Nonlinear Time History

The steel–concrete hybrid wind turbine tower is characterized by the concrete tubular segment at the lower part and the traditional steel tubular segment at the upper part. Because of the great change of mass and stiffness along the height of the tower at the connection of steel segment and concrete segment, its dynamic responses under seismic ground motions are significantly different from those of the traditional steel tubular wind turbine tower. Two detailed finite element models of a full steel tubular tower and a steel–concrete hybrid tower for 2.0 MW wind turbine built in the same wind farm are, respectively, developed by using the finite element software ABAQUS. The response spectrum method is applied to analyze the seismic action effects of these two towers under three different ground types. Three groups of ground motions corresponding to three ground types are used to analyze the dynamic response of the steel–concrete hybrid tower by the nonlinear time history method. The numerical results show that the seismic action effect by the response spectrum method is lower than those by the nonlinear time history method. And then it can be concluded that the response spectrum method is not suitable for calculating the seismic action effects of the steel–concrete hybrid tower directly and the time history analyses should be a necessary supplement for its seismic design. The first three modes have obvious contributions on the dynamic response of the steel–concrete hybrid tower.

Download Full-text

A simplified iterative approach for testing the pulse derailment of light rail vehicles across a viaduct to near-fault earthquake scenarios

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409720987410 ◽

2021 ◽

pp. 095440972098741

Author(s):

Ling-Kun Chen ◽

Peng Liu ◽

Li-Ming Zhu ◽

Jing-Bo Ding ◽

Yu-Lin Feng ◽

...

Keyword(s):

Ground Motions ◽

Simulation Software ◽

Light Rail ◽

Rail Transit ◽

Light Rail Transit ◽

Seismic Responses ◽

Near Fault ◽

Rail Vehicle ◽

Pulse Type ◽

The Impact

Near-fault (NF) earthquakes cause severe bridge damage, particularly urban bridges subjected to light rail transit (LRT), which could affect the safety of the light rail transit vehicle (“light rail vehicle” or “LRV” for short). Now when a variety of studies on the fault fracture effect on the working protection of LRVs are available for the study of cars subjected to far-reaching soil motion (FFGMs), further examination is appropriate. For the first time, this paper introduced the LRV derailment mechanism caused by pulse-type near-fault ground motions (NFGMs), suggesting the concept of pulse derailment. The effects of near-fault ground motions (NFGMs) are included in an available numerical process developed for the LRV analysis of the VBI system. A simplified iterative algorithm is proposed to assess the stability and nonlinear seismic response of an LRV-reinforced concrete (RC) viaduct (LRVBRCV) system to a long-period NFGMs using the dynamic substructure method (DSM). Furthermore, a computer simulation software was developed to compute the nonlinear seismic responses of the VBI system to pulse-type NFGMs, non-pulse-type NFGMs, and FFGMs named Dynamic Interaction Analysis for Light-Rail-Vehicle Bridge System (DIALRVBS). The nonlinear bridge seismic reaction determines the impact of pulses on lateral peak earth acceleration (Ap) and lateral peak land (Vp) ratios. The analysis results quantify the effects of pulse-type NFGMs seismic responses on the LRV operations' safety. In contrast with the pulse-type non-pulse NFGMs and FFGMs, this article's research shows that pulse-type NFGM derail trains primarily via the transverse velocity pulse effect. Hence, this study's results and the proposed method can improve the LRT bridges' seismic designs.

Download Full-text