This study aims to develop seismic Fragility curves for a typical pilesupported wharf. Fragility curve is one of the popular tools in seismic performance evaluation of a structure. The software FLAC2D was used to simulate the seismic performance of the wharf structure. Using eight time history records, occurred in past, as seismic loading, incremental dynamic analysis (IDA) was applied for seismic demand estimation. Based on the resulted seismic response matrix the analytical Fragility curves were developed. As a prevailing tool, adopted Fragility curves are useful for seismic risk assessment. They can also be used to optimize wharf-retrofit methods.

In this paper, a procedure has been presented to develop Fragility curves of structures equipped with optimal variable damping or stiffness semi-active tuned mass dampers (SATMDs). To determine proper variable damping or stiffness of semi-active devices in each time step, instantaneous optimal control algorithm with clipped control concept has been used. Optimal SATMDs have been designed based on minimization of maximum interstory drift of nonlinear structure which genetic algorithm(GA) has been used to solve the optimization problem. For numerical analysis, a nonlinear eight-story shear building with bilinear hysteresis material behavior has been used. Fragility curves for the structure equipped with optimal variable damping and stiffness SATMDs have been developed for different performance levels and compared with that of uncontrolled structure as well as structure controlled using passive TMD. Numerical analysis has shown that for most range of intensity measure optimal SATMDs have been effective in enhancement of the seismic Fragility of the nonlinear structures which the improvement has been more than passive TMDs. Also, it has been found that, although variable stiffness SATMD shows to be more reliable in lower mass ratios, however in higher mass ratios variable stiffness and damping SATMDs performs similarly to improve reliability of the structure.

Placing column lap-splice in the locations of possible nonlinear deformation may adversely affect the structures response to strong ground motions. Localization of damage in splice zone may change the structural response and prevent the load redistribution and development of a uniform pattern of nonlinear excursions among the various members. Validated by existing laboratory experiments, this study presents a model that could be used to evaluate the behavior of lap-spliced columns. The proposed model is able to include the effect of the longitudinal bars arrangement; bars yield stress, and the amount and spacing of transverse bars. Comparison with existing experimental tests, show a good correlation between the model and experimental results. Finally, to obtain an estimation of the importance of the bar slip in lap splice on the structures response, Fragility curves for life safety and collapse limit states are developed for an ordinary moment resisting frame of a one bay-ne story structure. Incremental dynamic analysis is used to derive the Fragility curves. These Fragility curves show that the bar slip have significant impact on the probability of exceeding collapse limit state, while its impact on the life safety limit state is not so significant.

Earthquakes are undoubtedly a most important natural disaster and, therefore, in recent decades, the seismic vulnerability assessment of existing buildings has become an important issue. One of the latest achievements in seismic vulnerability assessment is the seismic Fragility curve. Fragility curves describe how the reliability of a structure changes over a range of loading conditions to which a structure may be exposed. Approaches to developing Fragility curves can be classified into four main categories: judgmental, empirical, analytical, and hybrid. Fairly extensive studies have been done for concrete and steel structures and also for different types of bridges, while, for masonry buildings, only limited studies are available. Iran is in a high seismicity area in the world where a large number of masonry buildings have been constructed. In this study, an analytical approach was used to develop Fragility curves for 1 story, 2 story and 3 story masonry school buildings on different soils. In order to achieve more realistic Fragility curves, 24 analyses were performed for each building. The following conditions were considered in these analyses: applying lateral force in 2 main axes (x and y) and 2 main directions (positive and negative), eccentricity, applying lateral force in 2 cases (first mode and mass). The computer program, Tremuri, and the design spectrum of Standard No. 2800 have been used in this study. Finally, by assuming a log-normal distribution probability function, Fragility curves were obtained. It is worth noting that the peak ground acceleration (PGA) is selected as a parameter that represents the intensity of seismic ground motion.

There are a few methods for seismic vulnerability assessment of bridge structural systems. The development of vulnerability information in the form of Fragility curves is an approach when the information is to be developed accounting for a multitude of uncertain sources involved, such as, structural characteristics, estimation of seismic hazard and site condition. Inherent randomness is involved to these uncertain factors. The major effort of this study is placed on the development of empirical Fragility functions by utilizing the damage data from past earthquakes considering composite inherent randomness of the uncertain factors. The introduced procedure is suitable for the development of Fragility curves under the assumption that they can be presented by two-parameter lognormal distributions. The empirical Fragility curves are developed using 768 bridge damage data obtained from the 1994 Northridge and the 1995 Kobe earthquakes, which could be used as reference curves for seismic risk assessment studies of the similar bridges in Iran.

Structural damages and subsequently considerable economic losses that ever made in catastrophic seismic events caused reaserchers and codes gradually move from prescriptive design to performance-based design. Seismic Fragility analyses are one of the most important tools in performance-based seismic design of structures that lead to production of Fragility curves and functions. Fragility function is a capable tool for probabilistic assessment of the seismic vulnerability of the structures. In this study, in order to assess seismic vulnerability of corrugated steel shear walls and compare their seismic vulnerability with simple steel shear walls, Fragility functions have been developed and Fragility curves have been constructed. In this regard, the effect of the corrugation angle has been studied in corrugated models. Construction of these curves has became feasible through conducting incremental dynamic analyses. For this purpose, inter-story drift and peak ground acceleration have been used as damage measure and ground motion intensity measure, respectively. Assessment of resulted curves show that in low seismic intensity, probability of damage in corrugated models is reduced by increasing the corrugation angle; while, in high seismic intensity, probability of damage in corrugated models has been increased by increasing the corrugation angle. On the other hand, results indicate that corrugated models have more appropriate seismic performance than simple model in low seismic intensity.

Fixed pile-founded offshore platforms installed in the seismic-prone areas are exposed to the risk of earthquake-induced disastrous failure and costly operation interruption. Accordingly, the development of applied seismic evaluation methodologies for these infrastructures is a matter of utmost importance. In the context of performance-based earthquake engineering (PBEE), probabilistic seismic assessments of fixed pile-founded offshore platforms have been investigated, here. A three-dimensional (3D) finite element model of a recently installed platform located in the South Pars Oil and Gas field of the Persian Gulf has been made. Soil-pile-structure interaction, as well as dynamic site response effects, has been considered. Probabilistic seismic demand modeling (PSDM) has been employed to manifest the efficient and sufficient ground motion intensity measures (IMs) which can rigorously predict the structural engineering demand parameters (EDPs). Derived from probabilistic seismic demand analysis (PSDA), the superb results have been also evaluated by means of the predominantly used method of incremental dynamic analysis (IDA). On the other hand, the drawn findings contributed to representing the Fragility curves of the fixed pilefounded offshore platforms. The demonstrated results are highly recommended to be considered in related research.

Studies have been shown that conventional concentrically braced frames have undesirablity seismic performance since satisfy the displacement-controlled conditions in moment resistant frames are difficult. Then in the decades of 1970, researchers developed a system that had a good performance in strength and stiffness and in lateral displacement-controlled conditions either, the reason for this can be expressed that eccentrically braced frame (EBF) link acts as a fuse. Considering the limited research conducted in the field of investigating the seismic performance of eccentrically braced systems under strong ground motions by powerful dynamic nonlinear analyses, as well as knowing as much as possible the seismic behavior of these types of frames and choosing a suitable system to deal with seismic forces, the necessity of this research was felt. Therefore, in this paper, the seismic performance of 5, 10, and 15-story eccentrically braced frames with link beams with different types of performance in the ranges of shear, shear-flexural, and flexural performances has been investigated using incremental dynamic analyses (IDAs) under near-field ground motions. The results showed that, the performance of EBFs with Shear link in collapse prevention (CP) performance level are more desirable than EBFs with shear-flexural link and also performance of EBFs with shear-flexural link are more desirable than EBFs with Flexural link.