Masonry infill walls have many beneficial and disadvantageous effects on seismic performances of RC frames. Despite such remarkable effects, practicing engineers usually neglect the effects of infill walls on seismic behavior of structures. This study aims to demonstrate that neglecting the effects of infill walls during the nonlinear dynamic analysis of the RC frames may lead to the dramatic misunderstanding the seismic performance of the structure. To this end seismic response of 18 models of the same structure and different arrangements of the infill walls to four different ground motions were investigated using PERFORM 3D software. Results of this study revealed that changing the arrangement of infill walls may change the damage state of the building during an earthquake.

The purpose of this research is to study the seismic performance of railway embankments through a probabilistic approach. Nonlinear response history analyses were conducted utilizing PLAXIS software. Three categories of railway embankments were selected and more than 2400 embankment-earthquake case studies were performed. Sensitivity analyses were implemented to obtain the most important variables in the seismic performance of railway embankments. Finally, analytical fragility curves were generated in terms of the mechanical properties of railway embankments (e.g., soil cohesion and friction angle). Fragility functions were developed, employing an incremental dynamic analysis approach using a set of ground motions, including near- and far-field earthquakes. The maximum vertical displacement of the embankment was chosen as a damage index parameter. Fragility curves were derived for three damage states, including slight, moderate and extensive damage, with respect to threshold values proposed in the literature. The results of this study revealed that the mechanical properties of embankments could be considered one of the crucial uncertainty factors in seismic fragility analysis of railway embankments.

Steel cylindrical tanks are vital structures for storing various types of liquid in industrial plants or as a component in a water distributing system. As they sometimes are used to store toxic, flammable, and explosive material, their inapt performance during an earthquake may lead to catastrophic consequences. Therefore, practicing engineers, researchers, and industry owners are concerned about their structural safety. Meanwhile, the seismic performance of liquid storage tanks is rather complex. Thus, this subject has garnered many researchers’ interest in the past decades. This paper aims to briefly review the most significant studies on the seismic performance of on-ground steel cylindrical tanks. It focuses on analytical approaches and does not include experimental and on-site ones. Finally, the new horizons for the seismic performance assessment of such structures are presented herein.

Thin-walled cylindrical shells are important components of many industrial complexes. Most of these components have circular cutouts in manholes and pipe-to-shell junctions. Performance of cylindrical shells due to the extreme loading conditions shows that buckling is the major failure mode in such components. This study aims to indicate the effect of circular cutouts on buckling capacity of cylindrical shells due to pure axial compression. To this end, cylindrical shells of different geometric specifications and various arrangements and sizes of cutouts were considered. Numerical nonlinear analyses were conducted using ANSYS software. Result of this study revealed that cutouts can play a noticeable role in creating stress concentration and affect destructively the stability of structures. It is shown that there is a noticeable difference between the effects on cutouts in buckling of thinner shells and thicker ones. Cutouts reduce the local buckling capacity of shell about 10–15 % in the cylindrical shells, with the diameter to thickness ratio of less than 1,000. Meanwhile in shells with diameter to thickness, more than 1,000 such cutouts reduce the shell capacity about 30–35 %.

Steel built-up batten columns are common types of columns in Iran and some other parts of the world. They are economic and have acceptable performance due to gravity loads. Although several researches have been conducted on the behavior of the batten columns under axial loads, there are few available articles about their seismic performance. Experience of the past earthquakes, particularly the 2003 Bam earthquake in Iran, revealed that these structural members are seismically vulnerable. Thus, investigation on seismic performance of steel batten columns due to seismic loads and providing a method for retrofitting them are important task in seismic-prone areas. This study aims to investigate the behavior of concrete-filled batten columns due to combined axial and lateral loads. To this end, nonlinear static analyses were performed using ANSYS software. Herein, the behaviors of the steel batten columns with and without concrete core were compared. The results of this study showed that concrete-filled steel batten columns, particularly those filled with high-strength concrete, may cause significant increases in energy absorption and capacity of the columns. Furthermore, concrete core may improve post-buckling behavior of steel batten columns.