Category: Earthquake Engineering

Recent major earthquakes around the world have shown the vulnerability of
infrastructure and the need for research to better understand the nature of seismic
events and their effects on structures. As a result, earthquake engineering research has
been expanding as more and more data become available from a large array of seismic
instruments, large scale experiments and numerical simulations. This book presents
results from some of the current seismic research activities including threedimensional
wave propagation in different soil media, seismic loss assessment,
geotechnical problems including soil-structure interaction, and seismic response of
structural components and structures including historical and monumental structures,
bridge embankments, and different types of bridges and bearings.
First part of the book deals with seismic risk assessment and hazard analysis with a concentration on seismic microzonation, development of probabilistic hazard maps, geotechnical problems including soil-structure interaction, and three-dimensional
wave propagation in different soil media considering different surface characteristics and topography. Chapter 1 provides a methodology for seismic risk assessment within
a performance based earthquake engineering framework. Probabilistic hazard analysis and economic models are used for loss estimation and evaluation of earthquake impact on regional economies. Chapter 2 describes development of seismic
microzonation and probabilistic hazard maps for a specific region. Details of site characteristics including geological conditions and soil nonlinearity were considered
in the seismic zoning and hazard assessment. Chapter 3 presents cognitive methods for modeling geotechnical and seismological problems. New data-driven modern techniques are used to complement and improve the traditional physically-based
geotechnical modeling and system analysis under earthquake loading.

Category: Earthquake Engineering Bridge Under Seismic Loads Discussion of results

The response quantities obtained from both the response-spectrum analysis and the timehistory analysis included bending moments, shear forces, axial forces, and displacements. A detailed review of the response results showed that the observations from the shear forces and the axial forces were the same as those from the bending moments. Given this, only the bending moments and the displacements were used for the evaluation

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Category: Earthquake Engineering Bridge Under Seismic Loads Conclusions

The objective of this study was to investigate the performance of the Confederation Bridge due to seismic excitations expected at the bridge location. A finite element model of a typical segment of the bridge was subjected to selected seismic motions representative of the seismic hazard for the bridge location. The response results obtained from the dynamic analysis of the model were compared with the

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Category: Earthquake Engineering Bridge Under Seismic Loads Dynamic analysis and results

For the purpose of the seismic evaluation of the bridge, dynamic analyses were conducted on the bridge model to determine the responses due to seismic actions represented by the uniform hazard spectrum and the selected sets of records. Elastic material properties of the model were assumed in the analyses. The dynamic analyses included both responsespectrum analyses and time-history analyses. Response-spectrum analyses Response-spectrum analyses were

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Category: Earthquake Engineering Seismic excitations for time-history analysis

Given the uncertainties in the estimation of the seismic hazard for eastern Canada, a number of time-history analyses were conducted using excitation motions well beyond the scenario earthquake motions for the bridge location determined from the seismic hazard analysis as discussed in Section 3.3. In total, five groups of different seismic excitations were considered. Because of lack of strong seismic motion records in eastern

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Category: Earthquake Engineering Calibration of the model using data of full scale test

The model shown in Fig. 5 was calibrated using records of vibrations and tilts of the bridge obtained during a full scale tests of the bridge were conducted on April 14, 1997, about two months before the official opening of the bridge. The objectives of the tests were: (i) to measure the deflection of the bridge pier under static loads, and (ii) to

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Category: Earthquake Engineering Modelling of the bridge

The structural system of the bridge allows the development of a model of a selected segment of the bridge rather than modelling the entire bridge. Because of the repetitiveness of the units of the structural system (i.e., portal frames and drop-in girders) along the bridge, a proper model of a selected segment would be quite representative of the whole bridge. Figure 5 shows the

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Category: Earthquake Engineering Scenario earthquakes for the bridge location

The seismic hazard at a given site represents the sum of the hazard contributions of different earthquakes at different distances from the site. For each site, however, there are a few earthquakes that have dominant contributions to the hazard. These earthquakes are normally referred to as scenario or predominant earthquakes. The shape of the uniform hazard spectrum for a given site, representing the

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Category: Earthquake Engineering Seismic hazard for the bridge location

Since the development of the design parameters for the Confederation Bridge in early 1990s, there have been significant advances in the understanding of the seismic hazard in Canada. New source models, and most updated software have been used for the assessment of the seismic hazard. It should be mentioned, however, that there are still significant uncertainties in the estimation of seismic hazard. As

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Category: Earthquake Engineering Seismic design parameters

The design life of 100 years and the safety index of 4.0 were the basic design requirements for the Confederation Bridge. These requirements were much higher than those prescribed in the highway bridge design codes available at the time when the bridge was designed. The specified design life and safety index for the Confederation Bridge required special studies in order to determine the seismic

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Category: Earthquake Engineering Description of the bridge

The Confederation Bridge consists of two approach bridges at its ends and a main bridge between them (Fig. 1). The approach bridge at the Prince Edward Island end (i.e., the east end) is 555 m long and has 7 piers, and that at the New Brunswick end (i.e., the west end) is 1,275 m long and has 14 piers. The longest span of

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