Ground motion duration effects on nonlinear seismic response

2005 ◽  
Vol 35 (1) ◽  
pp. 21-38 ◽  
Author(s):  
Iunio Iervolino ◽  
Gaetano Manfredi ◽  
Edoardo Cosenza
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Nonlinear Seismic Response

Simplified BNWF model for nonlinear seismic response analysis of offshore piles with nonlinear input ground motion analysis

2005 ◽  
Vol 42 (2) ◽  
pp. 365-380 ◽  
Author(s):  
M Hesham El Naggar ◽  
Mohsen Ali Shayanfar ◽  
Mehrdad Kimiaei ◽  
Ali Akbar Aghakouchak
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Motion Analysis ◽  
Nonlinear Response ◽  
Free Field ◽  
Response Analysis ◽  
Winkler Foundation ◽  
Offshore Platforms ◽  
Nonlinear Seismic Response ◽  
Offshore Piles

The seismic response of pile-supported offshore structures is strongly affected by the nonlinear behavior of the supporting piles. Nonlinear response of the pile foundation is the most important source of potential nonlinearity in the dynamic response of offshore platforms to earthquake excitations. It is often necessary to perform a dynamic analysis of offshore platforms that accounts for soil nonlinearity, discontinuity conditions at pile–soil interfaces, energy dissipation through soil radiation damping, and structural nonlinear behaviors of piles. In this paper, an attempt is made to develop an inexpensive and practical procedure, compatible with readily available structural analysis software, for estimating the lateral response of flexible piles embedded in layered soil deposits subjected to seismic loading. In the proposed model a beam on nonlinear Winkler foundation (BNWF) approach, consisting of simple nonlinear springs, dashpots, and contact elements, is used. This model was incorporated into a finite element program, ANSYS, which was used to compute the response of laterally excited piles. A nonlinear approach was used for seismic free-field ground motion analysis. The computed responses compared well with the centrifuge test results. This paper deals with the effects of free-field ground motion analysis on nonlinear seismic behavior of embedded piles. Different parts of a BNWF model, together with quantitative and qualitative findings and conclusions for dynamic nonlinear response of offshore piles, are discussed and addressed in detail.Key words: nonlinear, seismic response, offshore piles, seismic pile–soil interaction, BNWF models.

scholarly journals Seismic rocking effects on a mine tower under induced and natural earthquakes

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Piotr Adam Bońkowski ◽  
Juliusz Kuś ◽  
Zbigniew Zembaty
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Ground Surface ◽  
Tall Buildings ◽  
Earthquake Ground Motion ◽  
Seismic Action ◽  
Seismic Effects ◽  
Copper Ore ◽  
Rotational Components ◽  
Natural Earthquakes

AbstractRecent research in engineering seismology demonstrated that in addition to three translational seismic excitations along x, y and z axes, one should also consider rotational components about these axes when calculating design seismic loads for structures. The objective of this paper is to present the results of a seismic response numerical analysis of a mine tower (also called in the literature a headframe or a pit frame). These structures are used in deep mining on the ground surface to hoist output (e.g. copper ore or coal). The mine towers belong to the tall, slender structures, for which rocking excitations may be important. In the numerical example, a typical steel headframe 64 m high is analysed under two records of simultaneous rocking and horizontal seismic action of an induced mine shock and a natural earthquake. As a result, a complicated interaction of rocking seismic effects with horizontal excitations is observed. The contribution of the rocking component may sometimes reduce the overall seismic response, but in most cases, it substantially increases the seismic response of the analysed headframe. It is concluded that in the analysed case of the 64 m mining tower, the seismic response, including the rocking ground motion effects, may increase up to 31% (for natural earthquake ground motion) or even up to 135% (for mining-induced, rockburst seismic effects). This means that not only in the case of the design of very tall buildings or industrial chimneys but also for specific yet very common structures like mine towers, including the rotational seismic effects may play an important role.

Wave Passage and Ground Motion Incoherency Effects on Seismic Response of an Extended Bridge

2011 ◽  
Vol 16 (3) ◽  
pp. 364-374 ◽  
Author(s):  
Aman M. Mwafy ◽  
Oh-Sung Kwon ◽  
Amr Elnashai ◽  
Youssef M. A. Hashash
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Wave Passage

Nonlinear Seismic Response of Rock Tunnels Crossing Inactive Fault under Obliquely Incident Seismic P Waves

2021 ◽  
Vol 32 (5) ◽  
pp. 1174-1189
Author(s):  
Hongyun Jiao ◽  
Xiuli Du ◽  
Mi Zhao ◽  
Jingqi Huang ◽  
Xu Zhao ◽  
...  
Keyword(s):  
Seismic Response ◽  
P Waves ◽  
Nonlinear Seismic Response ◽  
Obliquely Incident ◽  
Rock Tunnels

scholarly journals VERIFICATION OF NONLINEAR SEISMIC RESPONSE VALUES USED FOR THE SEISMIC RETROFIT DESIGN OF YOKOHAMA BAY BRIDGE

2010 ◽  
Vol 66 (1) ◽  
pp. 31-36
Author(s):  
Yasumiki YAMAMOTO ◽  
Hisamitsu HANNO ◽  
Yozo FUJINO ◽  
Masaaki YABE
Keyword(s):  
Seismic Response ◽  
Seismic Retrofit ◽  
Nonlinear Seismic Response ◽  
Retrofit Design

Seismic response and retrofit of industrial brick masonry chimneys

1992 ◽  
Vol 19 (1) ◽  
pp. 117-128 ◽  
Author(s):  
A. Ghobarah ◽  
T. Baumber
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Strong Motion ◽  
Brick Masonry ◽  
Wind Loading ◽  
Earthquake Ground Motion ◽  
Lumped Mass ◽  
Mass System ◽  
Higher Modes ◽  
Recent Earthquakes

During recent earthquakes, the documented cases of collapsed unreinforced brick masonry industrial chimneys are numerous. Observed modes of structural failure are either total collapse or sometimes collapse or damage of the top third of the structure. The objective of this study is to analyze and explain the modes of observed failure of masonry chimneys during earthquake events, and to evaluate two retrofit systems for existing chimneys in areas of high seismicity. The behaviour of the masonry chimney, when subjected to earthquake ground motion, was modelled using a lumped mass system. Several actual strong motion records were used as input to the model. The shear, moment, and displacement responses to the earthquake ground motion were evaluated for various chimney configurations. It was found that the failure of the chimney at its base is the result of the fundamental mode of vibration. Failure at the top third of the structure due to the higher modes of vibration is possible when the chimney is subjected to high frequency content earthquakes. Higher modes, which are normally not of concern under wind loading, were shown to be critical in seismic design. Post-tensioning and the reinforcing steel cage were found to be effective retrofit systems. Key words: masonry, chimneys, behaviour, analysis, design, retrofit, dynamic, earthquakes, seismic response.

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