Reliability Analysis of Seismic Isolation in Retrofitting of Simply Supported Bridges

2016 ◽  
Vol 847 ◽  
pp. 391-400
Author(s):  
Luigi Petti ◽  
Alessio Lodato ◽  
Angelo Mammone
Keyword(s):  
Seismic Isolation ◽  
Fragility Curves ◽  
Seismic Intensity ◽  
Finite Element Models ◽  
Design Strategies ◽  
Limit States ◽  
Damage Level ◽  
Simply Supported ◽  
Dynamic Analyses ◽  
Nonlinear Dynamic Analyses

The paper investigates the reliability of simply supported bridges, retrofitted or less with seismic isolation, by means of fragility curves, which represent the probability of reaching a certain damage level for an assigned seismic intensity. Taking advantage of the Multi Stripes methodology, several nonlinear dynamic analyses of a multi-span bridge representing the existing ones in Italy built in the 60 ' characterized by means of non linear finite element models in different design configurations of seismic retrofit have been carried out, in order to obtain the fragility functions.The obtained results allow to assess the isolation retrofit strategies effectiveness to mitigate the seismic risk of simply supported bridges, highlighting the influence of different design strategies on the probability of exceeding the limit states considered.

scholarly journals Assessment of Seismic Vulnerability of Steel and RC Moment Buildings Using HAZUS and Statistical Methodologies

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Iman Mansouri ◽  
Jong Wan Hu ◽  
Kazem Shakeri ◽  
Shahrokh Shahbazi ◽  
Bahareh Nouri
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Moment Frames ◽  
Limit States ◽  
Rc Frames ◽  
Dynamic Analyses ◽  
Damage States ◽  
Definition Of ◽  
Nonlinear Dynamic Analyses

Designer engineers have always the serious challenge regarding the choice of the kind of structures to use in the areas with significant seismic activities. Development of fragility curve provides an opportunity for designers to select a structure that will have the least fragility. This paper presents an investigation into the seismic vulnerability of both steel and reinforced concrete (RC) moment frames using fragility curves obtained by HAZUS and statistical methodologies. Fragility curves are employed for several probability parameters. Fragility curves are used to assess several probability parameters. Furthermore, it examines whether the probability of the exceedence of the damage limit state is reduced as expected. Nonlinear dynamic analyses of five-, eight-, and twelve-story frames are carried out using Perform 3D. The definition of damage states is based on the descriptions provided by HAZUS, which gives the limit states and the associated interstory drift limits for structures. The fragility curves show that the HAZUS procedure reduces probability of damage, and this reduction is higher for RC frames. Generally, the RC frames have higher fragility compared to steel frames.

Implications of cumulated seismic damage on the seismic performance of unreinforced masonry buildings

2014 ◽  
Vol 47 (2) ◽  
pp. 157-170 ◽  
Author(s):  
Amaryllis Mouyiannou ◽  
Andrea Penna ◽  
Maria Rota ◽  
Francesco Graziotti ◽  
Guido Magenes
Keyword(s):  
Nonlinear Dynamic ◽  
Fragility Curves ◽  
Seismic Damage ◽  
Unreinforced Masonry ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Seismic Capacity ◽  
Building Stock ◽  
Dynamic Analyses ◽  
Nonlinear Dynamic Analyses

The seismic capacity of a structure is a function of the characteristics of the system as well as of its state, which is mainly affected by previous damage and deterioration. The cumulative damage from repeated shocks (for example during a seismic sequence or due to multiple events affecting an unrepaired building stock) affects the vulnerability of masonry buildings for subsequent events. This paper proposes an analytical methodology for the derivation of state-dependent fragility curves, taking into account cumulated seismic damage, whilst neglecting possible ageing effects. The methodology is based on nonlinear dynamic analyses of an equivalent single degree of freedom system, properly calibrated to reproduce the static and dynamic behaviour of the structure. An application of the proposed methodology to an unreinforced masonry case study building is also presented. The effect of cumulated damage on the seismic response of this prototype masonry building is further studied by means of nonlinear dynamic analyses with the accelerograms recorded during a real earthquake sequence that occurred in Canterbury (New Zealand) between 2010 and 2012.

scholarly journals Seismic Assessment via EC8 of Modern Heritage Structures

2016 ◽  
pp. 1002-1021
Author(s):  
Gerardo M. Verderame ◽  
Flavia De Luca ◽  
Gaetano Manfredi
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Models ◽  
Fragility Curves ◽  
Seismic Assessment ◽  
Eurocode 8 ◽  
Dynamic Identification ◽  
Limit States ◽  
Rc Building ◽  
Nonlinear Dynamic Analyses ◽  
Modal Dynamic Identification

Given the interest earned recently by modern heritage structures, seismic assessment criteria of Eurocode 8, for ordinary reinforced concrete structures, are applied to a modern heritage RC building. The case study, the Tower of the Nations in Naples, allows a discussion on knowledge approaches, analysis methodologies and modeling choices that can be considered. Modal dynamic identification, in situ inspections, and testing provided the necessary knowledge of the structure. Linear and nonlinear models of the structure are built up accounting for tuff infills' stiffness and strength contribution. Numerical modal properties are compared with those obtained through dynamic identification. Lumped plasticity model for reinforced concrete elements and equivalent strut macro models for tuff and concrete infills are employed for the nonlinear model of the structure. Seismic assessment through nonlinear dynamic analyses is carried out for two Limit States. Finally, fragility curves through cloud analysis are obtained for the different limit states considered.

Identification of Suitable Limit States from Nonlinear Dynamic Analyses of Masonry Structures

2014 ◽  
Vol 18 (2) ◽  
pp. 231-263 ◽  
Author(s):  
Amaryllis Mouyiannou ◽  
Maria Rota ◽  
Andrea Penna ◽  
Guido Magenes
Keyword(s):  
Nonlinear Dynamic ◽  
Masonry Structures ◽  
Limit States ◽  
Dynamic Analyses ◽  
Nonlinear Dynamic Analyses

scholarly journals Fragility Assessment of Geotechnical Seismic Isolated (GSI) Configurations

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5088
Author(s):  
Davide Forcellini
Keyword(s):  
Developing Countries ◽  
Finite Element ◽  
Seismic Isolation ◽  
Fragility Curves ◽  
Low Cost ◽  
Soil Layer ◽  
Seismic Energy ◽  
Finite Element Models ◽  
Numerical Finite Element ◽  
Mitigation Technique

Geotechnical seismic isolation (GSI) consists of an innovative technique to mitigate the effects of earthquakes based on interposing a superficial soil layer to filter the seismic energy from the soil to the structure. This approach is particularly applied in developing countries due to low-cost applications. In order to account the uncertainties, the presented paper aimed to develop fragility curves of 3D configurations performed by numerical finite element models. The mail goal is to assess and discuss the potentialities of GSI as a mitigation technique for several configurations. Opensees PL has been applied to perform the numerical analyses and to realistically reproduce the behaviour of GSI.

Assessment of Stiffening Type of the Cutout in Tubular Wind Turbine Towers Under Artificial Dynamic Wind Actions

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
Christoforos A. Dimopoulos ◽  
Konstantina Koulatsou ◽  
Francesco Petrini ◽  
Charis J. Gantes
Keyword(s):  
Wind Turbine ◽  
Structural Performance ◽  
Wind Loading ◽  
Finite Element Models ◽  
The Public ◽  
Dynamic Analyses ◽  
Time Histories ◽  
Wind Actions ◽  
Wind Turbine Towers ◽  
Nonlinear Dynamic Analyses

The effectiveness of alternative stiffening types of the cutout provided near the base of tubular steel wind turbine towers is assessed, taking into account the dynamic nature of wind loading. To that effect, artificial wind load time histories are first obtained using the public domain aero-elastic code FAST. Finite element models that have been previously validated by means of comparison with experimental results, are then used to carry out fully nonlinear dynamic analyses and compare strength and overall structural performance.

scholarly journals State of the art of fragility analysis for major building types in China with implications for intensity-PGA relationships

2018 ◽  
Author(s):  
Danhua Xin ◽  
James Edward Daniell ◽  
Friedemann Wenzel
Keyword(s):  
State Of The Art ◽  
Fragility Curves ◽  
Seismic Intensity ◽  
Loss Assessment ◽  
Limit States ◽  
The Past ◽  
Earthquakes In China ◽  
Chinese Official ◽  
Macroseismic Intensities ◽  
Haicheng Earthquake

Abstract. The evaluation of the seismic fragility of buildings is one key task of earthquake safety and loss assessment. Many research reports and papers have been published over the past four decades that deal with the vulnerability of buildings to ground motion caused by earthquakes in China. We scrutinize 69 papers with studies of building damage for magnitude ≥ 4.7 events occurred in densely populated areas starting with the 1975 M7.5 Haicheng earthquake. They represent observations where macroseismic intensities have been determined according to the Chinese Official Seismic Intensity Scale. From these many studies we derive the most representative fragility functions (dependent on intensity) for 4 damage limit states of two most widely distributed building types: masonry and reinforced concrete. We also inspect 18 papers that provide analytical fragility curves (dependent on PGA) for the same damage classes and building categories. Finally, we check the consistency of fragilities as functions of intensity and PGA and derive corresponding relationships between macroseismic intensity and PGA. The intensity-PGA relationship developed in this study is fully compatible with results of previous research.

scholarly journals Seismic Assessment via EC8 of Modern Heritage Structures

2015 ◽  
pp. 607-628
Author(s):  
Gerardo M. Verderame ◽  
Flavia De Luca ◽  
Gaetano Manfredi
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Models ◽  
Fragility Curves ◽  
Seismic Assessment ◽  
Eurocode 8 ◽  
Dynamic Identification ◽  
Limit States ◽  
Rc Building ◽  
Nonlinear Dynamic Analyses ◽  
Modal Dynamic Identification

Given the interest earned recently by modern heritage structures, seismic assessment criteria of Eurocode 8, for ordinary reinforced concrete structures, are applied to a modern heritage RC building. The case study, the Tower of the Nations in Naples, allows a discussion on knowledge approaches, analysis methodologies and modeling choices that can be considered. Modal dynamic identification, in situ inspections, and testing provided the necessary knowledge of the structure. Linear and nonlinear models of the structure are built up accounting for tuff infills' stiffness and strength contribution. Numerical modal properties are compared with those obtained through dynamic identification. Lumped plasticity model for reinforced concrete elements and equivalent strut macro models for tuff and concrete infills are employed for the nonlinear model of the structure. Seismic assessment through nonlinear dynamic analyses is carried out for two Limit States. Finally, fragility curves through cloud analysis are obtained for the different limit states considered.

Numerical and Experimental Studies on the Seismic Retrofit of Simply Supported Bridges Using Superelastic Restrainers

2012 ◽  
Vol 446-449 ◽  
pp. 3291-3294
Author(s):  
Donatello Cardone ◽  
Salvatore Sofia
Keyword(s):  
Nonlinear Dynamic ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Seismic Retrofit ◽  
Shaking Table ◽  
Bridge Structure ◽  
Shaking Table Tests ◽  
Simply Supported ◽  
Dynamic Analyses ◽  
Nonlinear Dynamic Analyses

In this paper, the effectiveness of Shape Memory Alloys (SMA) restrainers for the seismic retrofit of multi-span simply supported deck bridges is investigated through a series of numerical nonlinear dynamic analyses and shaking table tests on an experimental mock-up of a typical bridge structure. Both numerical analyses and experimental tests have been carried out on the structure with and without seismic restrainers. The results of these studies clearly prove the effectiveness of the SMA-based restrainers in controlling the displacement response of simply supported deck bridges.

scholarly journals Analytical Fragility Curves of Pile Foundations with Soil-Structure Interaction (SSI)

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 66
Author(s):  
Davide Forcellini
Keyword(s):  
Soil Structure ◽  
Fragility Curves ◽  
Pile Foundations ◽  
Soil Structure Interaction ◽  
Cohesionless Soil ◽  
Seismic Behaviour ◽  
Limit States ◽  
Linear Dynamic ◽  
Ductility Factor ◽  
Dynamic Analyses

Pile foundations is a well-studied technique with many applications and its benefits on structures have been widely studied in the literature. In particular, the mutual effects of pile flexibility and soil deformability may significantly modify the seismic behaviour of superstructures. In order to consider the uncertainties that are connected with these issues, the paper applies the probabilistic-based approach of fragility curves by proposing three limit states based on ductility factor. Non-linear dynamic analyses were performed with OpenSees PL to assess the potentialities of three pile configurations founded on three cohesionless soil with different deformability.

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