Given the inherently time-consuming nature of incremental dynamic analysis (IDA), which requires extensive computational resources to simulate multiple ground motions and assess various structural responses, it is essential to explore more efficient methodologies that maintain accuracy while reducing analysis time. The MPA-based IDA algorithm (MIDA) is being developed for various structures to address the limitations of IDA. In this study, six individual masonry structures were examined, including three walls with varying perforation dimensions and three three-dimensional buildings subjected to two retrofitting conditions. These structures were analyzed using 30 ground motion accelerations. The masonry structures, reinforced with either a shotcrete layer or a coating application, were evaluated as homogeneous and anisotropic materials using a finite element-based macro-modeling approach. Additionally, IDA was performed, and the maximum displacement of the masonry structures was compared to that of the MIDA. The results indicate that, except under high surcharge conditions, the MIDA procedure not only significantly reduces computational time but also provides reasonable accuracy compared to the IDA precision algorithm. Therefore, it can be concluded that the difference between the IDA and MIDA methods is influenced by the lateral stiffness of the masonry structures being analyzed

BRBs are a new type of seismic resistance system that is being used extensively nowadays due to their enhanced seismic performance than conventional braces. In BRB braces, because the buckling of the steel core is prevented, the structure shows more stable behavior. In this type of bracing, the hysteresis performance of the bracing is similar to the hysteresis performance of the core material. Another feature of these braces is that the ductility of the steel material occurs over a considerable length of the brace. Although BRB braces are capable of dissipating large amounts of energy, they are unable to eliminate their residual strains. In other words, they do not have the property of self-centering. This leads to the non-return of the structure and to its original configuration after the seismic excitations; in the absence of a return mechanism. There may arise many permanent deformations in the structure during an earthquake. To overcome these permanent deformations, various innovative solutions have been developed in the construction of steel frames, including the use of shape memory alloys (SMA) that have two prominent features of shape memory and superelastic behavior and can return to their original position after subjected to the various loadings condition. In recent years, beside the Nitinol shape memory alloy (NiTi), Iron-based shape memory alloys (SMA-Fe), which have many advantages over previous SMAs and particularly due to their lower cost, have been introduced and being used in many construction projects.  In this research, the seismic behavior of structures braced with BRB, and iron-based shape memory alloy and Nitinol shape memory alloys has been investigated. Seismostruct finite element software has been used to model these systems. incremental dynamic analysis (IDA) has been performed on seven story structures equipped with X braces with different materials. The results of this study show that braced structures with iron-base shape memory alloys undergo less maximum displacement and permanent displacement compared to nitinol-braced structures. However, these structures experience more maximum displacement than BRB braced structure. The more the structures enter the nonlinear stage (in the maximum values of the relative inter-floor displacement demand) the more the dispersion of the results increases and the structure is more affected by the input accelerometers. The structure with buckling bracing will reach instability later than the two structures with shape memory alloy bracing. It is also observed that the elastic stiffness (slope of the linear behavior region) in all 3 braced frames is equal to each other. And finally, the IDA curve of the BRB structure is higher than the two shape memory alloy structures, and at equal acceleration, it is clear that the displacement of the shape memory alloy structures is more than the buckling structure, and it can also be seen that the iron-based shape memory alloy brace has a favorable performance and its curve is slightly higher than the NiTi shape memory alloy. Also, two shape memory alloy structures move almost together and reach instability at one point. According to the curves, it seems that the braced structures with shape memory alloys have performed well and until these structures reach instability.

It is generally accepted that performance-based design has to be reliability-based. Seismic performance evaluation is based on nonlinear dynamics and reliability theory taking into account uncertainties during analysis. Considering the economic importance of jacket type offshore platforms, the present research aims to assess the seismic performance of offshore steel platforms. In this study, three platforms located in the Persian Gulf were modeled using three dimensional structural modeling tools. Each platform was modeled and analyzed using both rigid and pinned connections. Reliability analysis was performed in accordance with Federal Emergency Management Agency (FEMA) guidelines using the results of incremental dynamic analysis for the three platforms. The results showed that platforms possessing rigid connections provide the desired confidence level of FEMA for the performance level of collapse prevention while only one platform with pinned connections was able to provide the desired confidence level.

Process towers or vertical vessels are among the industrial structures that play a key role in the production process of petroleum products and their derivatives in refineries and oil and gas industries. Due to the vulnerability of these structures in past earthquakes, and the lack of valid regulations and methods for seismic analysis and design of these structures, a case study on a designed and constructed process tower 26.5 meters high, located in Qeshm Island Refinery, has been conducted in this research. Since considering a rigid foundation, without the interaction of soil and structure, may lead to wrong results, in this study, the tower has been modeled in Abaqus finite element software considering soil behavior. The Winkler model used for soil modeling and the seismic behavior of the tower was investigated using pushover and incremental dynamic analysis, and finally, the resulting fragility curve is presented to show the structure's vulnerability at different levels of seismic intensities. In this investigation, the probable failures, including the failure of the body and the skirt, as well as the overturning of the structure, have been investigated. According to the incremental dynamic analysis results, no buckling was observed in the body and the tower's skirt before the tower overturned. The results show that overturning was the predominant failure mode and the probability of this failure mode until PGA=0.1g is approximately equal to zero, and for PGA= 0.35g, this probability is less than 20%. But for rare seismic intensities, the overturning probability is considerable.

incremental dynamic analysis (IDA) is a parametric analysis method that has recently emerged in several different forms to estimate more thoroughly structural performance under seismic loads. It involves subjecting a structural model to one (or more) ground motion record(s), each scaled to multiple levels of intensity, thus producing one (or more) curve(s) of response parameterized versus intensity level. Of great interest in Performance-Based Earthquake Engineering (PBEE) is the accurate estimation of the seismic performance of structures, and in particular, the mean annual frequency (MAF) of exceeding a specified structural demand or a certain limit-state capacity.In this study the behavior of a jacket type offshore platform with different characteristics in its two directions, separately and with 3D modeling considering pile-soil-structure interaction is investigated. By obtaining the IDA curves and summarizing the results, the behavior of the jacket is studied.All analyses are performed using OpenSees software. It is observed that the difference of geometry of jacket in two directions due to employing Float Over Deck (FOD) installation method, does not cause similar behavior in both directions and finally in direction with float over installation design requirement is not satisfied.

The vulnerability of industrial plants to natural hazards has made the world worried because of countries' general disability about the prediction of the level of effects and preparedness for the consequences of these types of events. For this purpose, seismic assessment of plant equipment is a strategic issue. One of the most equipment that is used in most oil & gas plants is stack flares. Stack flares are a type of stacks that are used for burning additional flammable gases before causing any other problem for other plant facilities. Proper seismic assessment of this type of equipment has been missed in the past and its exact performance evaluation can be effective in determining probable damages in future earthquakes and distinguishing the weakness of components of this type of structure. In this study, probabilistic seismic behavior of two designed and constructed stack flares is investigated and using incremental dynamic analysis their fragility curve and behavior factor are calculated. Results show that in ordinary intensities, the seismic demand of these structures is not considerable but in the range of rare intensities, extreme damages are probable. Also, in the above case studies, the performance of the 4-sided stack with respect to 3-sided stack was more proper and seems more assessment is needed on the suggested behavior factor by codes.

Reduction and management of risk of industrial plant especially energy is an important concern. Probabilistic and reliability method are used in risk and cost estimations. Oil, Gas and Petrochemical plant are the most energy producer plants that are in focus of cost, life and operation. These plants consist of several units, parts and equipment’s. In order to study the risk of plants, it is needed to study the equipment’s. The main goal of this research is probabilistic seismic assessment of fixed horizontal vessels. In this paper, finite element model of designed and constructed vessels in a real project is prepared and incremental dynamic analysis (IDA) is performed. Response of vessels components including the vessel body stress, piping stress, flange and elbow deformations, anchor bolt stress are extracted and their related limit state are defined. Finally the fragility curve of vessels components is prepared. The result shows that flange connection is the components that are potential for starting the damage of vessels.

Direct analysis method is a new approach on stability design of steel structures. This method consider second order effects by applying lateral force and reducing stiffnesses, however the effective length method consider these effects by increasing column length. The direct analysis method takes the effective length factor unity for all members. Joints displacement, out of straightness and out of plumbness as initial imperfections can be modeled directly or alternatively by applying notional loads in design considerations. Inelasticity and geometric nonlinearities calculated by reducing member stiffness in design considerations. In heavy oil structures, significant gravity loads and column length lead to more second order effects in compare to typical structures. This study evaluates and compares nonlinear dynamic analysis responses of designed heavy oil structures in both direct analysis method and effective length method based on ANSI/AISC 360-10 provisions.