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1

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.

2

Ground liquefaction and deformation analysis of breakwater structures under earthquakes

Zhao J., Wang Y., Yun G., Ashraf M. A.

Polish Maritime Research

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2016

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S 1

109--114

EN

Ground liquefaction and deformation is one of the important causes that damage engineering structures. Chinese current code for seismic design of breakwater is based on the single-level seismic design method as well as code for port and water-way engineering. However, this code can not exactly reflect the seismic performance of breakwater structures which experience different seismic intensities. In this paper, the author used a finite difference software, namely, FLAC3D, to analyze the state and compute seismic responses of breakwater structure. The breakwater foundation’s pore pressure ratio and displacement due to different earthquake have been studied. And the result show that: Smaller earthquakes have little influence on serviceability of the foundation, and severe earthquakes can liquefy some parts of the foundation; In the latter case , obvious changes of pores and foundation displaces can be found. Particularly, when seismic peak acceleration reachs 0.2g, Liquefaction appears in the foundation and mainly concentrated in the upper right side of the structure. In addition, the survey of ultra-hole pressure and displacement values of sand layers of the breakwater, manifests when the ultra pore pressure near 1.0, displacement and overturning structure is relatively large, resulting in varying degrees of damage to the structure. This paper’s research can provide theoretical and designable reference for similar engineering structures.

3

Przyczółki z gruntu zbrojonego geosyntetykami

Kazimierowicz-Frankowska K.

Mosty

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2016

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nr 1

26--31

PL

W artykule omówiono zalety i wady stosowania geosyntetyków w budownictwie mostowym. Główną uwagę zwrócono na możliwości wykorzystania tych materiałów do budowy przyczółków mostowych. Przedstawiono przykłady zastosowań i omówiono zasady wykonywania takich konstrukcji. Przedyskutowano problem projektowania sejsmicznego przyczółków z gruntu zbrojonego.

EN

The paper presents the advantages and disadvantages of using geosynthetics in bridge constructions. Special attention is paid to geosynthetic-reinforced soil (GRS) bridge abutments. Examples of applications and principles of constructing structures of this kind are presented. The problem of seismic design of GRS bridge abutments is also discussed.

4

Preventing irregularity effects of infills through modifying architectural drawings

Noorifard A., Tabeshpour M. R., Saradj F. M.

Architecture Civil Engineering Environment

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2016

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Vol. 9, no. 2

77--92

EN

Experiences of past earthquakes show that some designed and constructed buildings by engineers have been damaged during earthquakes because of negative effects of infill walls. The main aim of this paper is to prevent the amount of overall detrimental effects of infill walls such as torsion and soft story in a conventional residential building based on seismic codes of some countries and to use the maximum potential of walls. The results show that building in construction condition may suffer torsion because infills which are not modelled in design process are attached to the structure in construction phase. Contrary to the initial impression that there is a soft story in municipal buildings because of parking on ground floor, in buildings with architectural plan similar to the analyzed one, soft story would not happen. Furthermore, this case study proves that it is possible to prevent irregularity effects of infills through modifying architectural drawings without fundamental changes in concept, functional and aesthetic aspects. For modifying architectural drawings an algorithm is proposed in this research.

PL

Doświadczenia ostatnich trzęsień ziemi pokazują, że niektóre budynki zaprojektowane i skonstruowane przez inżynierów zostały zniszczone podczas trzęsienia ziemi na skutek negatywnego wpływu ścian wypełniających. Głównym celem tego artykułu jest zapobieżenie tym szkodliwym wpływom takim jak skręcanie i wiotkie kondygnacje w tradycyjnych budynkach mieszkalnych w oparciu o normy sejsmiczne niektórych krajów oraz przy wykorzystaniu maksymalnego potencjału ścian. Wyniki pokazują, że budynki w trakcie budowy mogą cierpieć na skutek skręcenia z powodu wypełnień, które nie są modelowane w procesie projektowania, a dopiero dołączone do konstrukcji na etapie realizacji. Wbrew początkowemu wrażeniu, że ze względu na zlokalizowanie parkingu na parterze w budynkach komunalnych istnieje wiotka kondygnacja, w budynkach o rzucie zbliżonym do analizowanego do powstania wiotkiej kondygnacji nie dojdzie. Ponadto, ta analiza przypadku dowodzi, że jest możliwe, aby zapobiec wpływom wynikającym z nieregularności wypełnień poprzez modyfikację rysunków architektonicznych bez zasadniczych zmian w koncepcji oraz aspektów funkcjonalnych i estetycznych. W artykule przedstawiono propozycję algorytmu do modyfikowania rysunków architektonicznych.

5

Determination of inelastic seismic demands of RC moment resisting setback frames

Varadharajan S., Sehgal V. K., Saini B.

Archives of Civil and Mechanical Engineering

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2013

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Vol. 13, no. 3

370--393

EN

In this paper, an extensive parametric study is conducted on plane RC moment resisting frames with setbacks. Firstly, a parameter called as "irregularity index" is proposed based on the dynamic characteristics of the frame to quantify the setback irregularity. Secondly, this paper aims to determine the affect of setback presence on inelastic deformation demands. To achieve this purpose, building frames with different arrangements of setbacks are modeled and designed in accordance with the European standard code of practice. These frames are subjected to an ensemble of 13 ground motions scaled to different intensities in order to obtain different performance levels as prescribed by SEAOC 1995 and analyzed by time history analysis. Results of the analytical study indicate strong influence of the parameters like beam–column strength ratio, number of stories, geometrical irregularity and the performance level under consideration on inelastic seismic demands. Furthermore, a seismic response database consisting of 13,728 non-linear dynamic analyses is generated, and non-linear regression analysis is performed on this database to propose simple formulae to estimate different seismic parameters in terms of the proposed irregularity index. The applicability of author proposed equations in PBD and DBD is briefly discussed.