This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

Seismic Rehabilitation of Existing Buildings

Structure–soil–structure interaction: Literature review

A vulnerability model capable of providing the probabilistic distribution of loss ratio for a set of intensity measure levels is a fundamental tool to perform earthquake loss estimation and seismic risk assessment. The aim of the study presented herein is to develop a set of vulnerability functions for 48 reinforced concrete building typologies, categorized based on the date of construction (which has a direct relation with the design code level), number of storeys (height of the building) and seismic zonation (which affects the design of the buildings). An analytical methodology was adopted, in which thousands of nonlinear dynamic analyses were performed on 2D moment resisting frames with masonry infills, using one hundred ground motion records that are compatible, to the extent possible, with the Portuguese tectonic environment. The generation of the structural models was carried out using the probabilistic distribution of a set of geometric and material properties, compiled based on information gathered from a large sample of drawings and technical specifications of typical Portuguese reinforced concrete buildings, located in various regions in the country. Various key aspects in the development of the vulnerability model are investigated herein, such as the selection of the ground motion records, the modelling of the infilled frames, the definition of the damage criterion and the evaluation of dynamic (i.e. period of vibration) and structural (i.e. displacement and base shear capacity) parameters of the frames. A statistical bootstrap method is demonstrated to estimate the variability of the loss ratio at each intensity measure level, allowing the estimation of the mean, as well as 10 and 90 % percentile vulnerability curves.

Investigation of the characteristics of Portuguese regular moment-frame RC buildings and development of a vulnerability model

This paper presents a numerical investigation of buckling restrained brace (BRB) frames (BRBF) and a comparison with concentrically braced frames (CBF). A simplified core-spring finite element model was used to model BRB elements. Four types of CBF (X, V, inverted V, and two-story X) and four types of BRBF (diagonal, V, inverted V, and two-story X) were modeled in ABAQUS. A static nonlinear pushover analysis considering two cyclic loading protocols showed that the buckling restraint allows the BRB elements to undergo significant plasticity without forming plastic hinges , thereby dissipating a proportionally larger amount of energy and delaying yielding in the frame elements. Results indicated dramatic improvements in energy dissipation and ductility in BRBF models as compared to equivalent CBF models. Seismic response modification factors for BRBF models also showed greater values over CBF models. Time-history analysis evaluated the performance of CBF and BRBF under historical earthquake loadings and supported the same conclusions. The best performance was observed for V, inverted V, and two-story X BRBF configurations; the diagonal BRBF configuration performed better than equivalent CBF models, but did not perform nearly as well as the other BRBF models.

Numerical evaluation of the hysteretic behavior of concentrically braced frames and buckling restrained brace frame systems

https://www.tpbin.com/Uploads/Subjects/8e44bf30-c8af-49f1-aba2-09acf3ea2909.pdf

Numerical and experimental study of hysteretic behavior of cylindrical friction dampers

http://jafari3000.persiangig.com/document/Article(11-20)/1-s2.0-S0143974X11000708-main.pdf

Experimental optimization studies on steel core lengths in buckling restrained braces

The performance study of high-rise towers has been attracting attention recently. Powerful analysis methods are used to assess local and global behaviour of tall structures. Incremental Dynamic Analysis (IDA) is one the most powerful methods for accurate estimation of seismic performance of structures.



In this paper, IDA is applied on high-rise towers, specifically Tehran telecommunication tower. Three different finite element models have been developed. The first model is a two-dimensional fibre beam element model on which IDA is applied. The other two models are finely meshed three-dimensional elastic and inelastic multi-axial-element-based models, which are used to investigate the validity of the two-dimensional model. Furthermore, the efficiency of different Intensity Measures and Engineering Demand Parameters is investigated. The results show that there is a good agreement between the results of two-dimensional and three-dimensional models in linear and nonlinear domains. It is also observed that Sa(T1) is more efficient than peak ground acceleration (PGA) as spectral acceleration is a structural specific intensity measure in comparison with, which is site-specific. Copyright © 2009 John Wiley & Sons, Ltd.

Incremental dynamic analysis of high-rise towers

In some cases, tall buildings are located in geotechnically unsuitable places, due to their high ratio of height to width; there is risk of uplift and other effects such as overturning and reduction structure serviceability during earthquake. This research is aimed to evaluate the effect of Soil-Structure Interaction (SSI) on seismic behavior of two adjacent 32 story buildings such as time period, base shear and displacements. The interaction effects are investigated for variable distance between the two buildings. Three types of soil such as soft clay, sandy gravel and compacted sandy gravel are considered for this study. The result obtained that the interaction effect increases time period of both buildings base shear and lateral displacement of the structures increases.

/pdf/soil-structure-interaction-between-two-adjacent-buildings-2pz0555hbk.pdf

Masoud Mirtaheri

Papers

Numerical and experimental study of hysteretic behavior of cylindrical friction dampers

Experimental optimization studies on steel core lengths in buckling restrained braces

Incremental dynamic analysis of high-rise towers

Soil Structure Interaction between Two Adjacent Buildings under Earthquake Load

An updated Lagrangian finite element formulation for large displacement dynamic analysis of three-dimensional flexible riser structures