The design spectrum presented in the Iranian Seismic Design Code for Petroleum Facilities (Publication-038) is derived from the design spectrum of the US ASCE 7-02 code. It is based on two spectral accelerations SS and S1. Considering that the spectral acceleration values of SS and S1 are not available for the seismic regions of Iran and since the seismic design spectrum in Iran is the code-2800, which is based on the maximum acceleration of bedrock A. In this article, we adapt the seismic design spectrum of Publication-038 with the seismic design spectrum of the code-2800. Thereby, we calculate the values of SS, S1, SDS and SD1 according to the four seismic zones of Iran and based on the four classifications of ground condition in code-2800 and provide the design spectra. in the other part, the evaluation of acceleration transfer coefficients to the ground surface (Fa and Fv) presented in publication-038 is discussed. The results show that the range of these coefficients is not appropriate to the seismic conditions of Iran. Therefore, the suggested range for the mentioned coefficients is presented based on the values of SS, S1 and according to the seismic conditions of Iran. In the other part of this research, the coefficients and relationships used in the publication-038 are evaluated. Investigations show that some of the relations and coefficients used in publication-038 are taken directly from the ASCE 7-02 regulations and based on the results of this study, they are not suitable for the seismic conditions of Iran.

This article provides a comparison process on how to calculate seismic forces by the static analysis method stated both in the international Building Code (IBC) 2003 and in the Iranian Seismic Code (IS 2800-05). The seismic coefficient for the equivalent lateral force is specified by the following factors: fundamental period, importance factor, spectral response acceleration, and building response modification factor. In this article the above-mentioned parameters are obtained through the IBC 2003 and are compared against those covered in the IS 2800-05. Studies and comparison of factors would lead to significant differences in the results obtained using the two codes. In order to clarify the problem, design base shear of a building with combined system (special moment steel frames + eccentric bracings) in four different soil types and vertical distribution of base shear at story level is obtained, in accordance with both codes; and the results are compared with diagrams and tables. The results prove the need to review the IS 2800-05 and develop more appropriate relations towards achieving economic and functional objectives.

The uncertain nature of future ground motions is leading to development of probabilistic structural damage estimation procedures. Fragility curves are useful tools for showing the probability of structural damage due to earthquakes as a function of ground motion indices. The contribution of this study is to develop the fragility curves for mid-rise RC frames designed according to the Iranian Seismic Design Code. These structures constitute the most vulnerable construction type in Iran well as several other countries prone to earthquakes. Sample 4, 6 and 8 story buildings were designed according to the Iranian seismic code. Incremental nonlinear dynamic analyses were performed for these sample buildings using ten near-fault ground motions to determine the maximum inter-story drift ratio. Based on those ratio fragility curves were developed in terms of peak ground acceleration for immediate occupancy and life safety damage levels with lognormal distribution assumption. The results show that sample frame structures do not satisfy performance objectives of Standard No.2800.

Setback in elevation of a structure is a special irregularity with considerable effect on its seismic performance. This paper addresses multistory Reinforced Concrete (RC) frame buildings, regular and irregular in elevation. Several multistory Reinforced Concrete Moment Resisting Frames (RCMRFs) with different types of setbacks, as well as the regular frames in elevation, are designed according to the provisions of the Iranian national building code and Iranian seismic code for the high ductility class. Inelastic dynamic time-history analysis is performed on all frames subjected to ten input motions. The assessment of the seismic performance is done based on both global and local criteria.Results show that when setback occurs in elevation, the requirements of the life safety level are not satisfied. It is also shown that the elements near the setback experience the maximum damage. Therefore it is necessary to strengthen these elements by appropriate method to satisfy the life safety level of the frames.

Height of the buildings directly affects the seismic performance and behavior of the structure during the earthquakes. This parameter is also significant when the structure is excited by two consequent ground motions. This paper presents the results of a study on the effect frame height on the seismic performance under two successive strong ground motions. It has been shown that, when the consequence of the first event remain in the structure as damage, the building often shows different dynamic characteristics as well as more vulnerability during the second seismic event. Three RC moment resisting frames with 4, 8 and 15 stories are designed based on the latest version of Iranian code of seismic design of buildings referred as Standard No. 2800 (STD 2800). The frames are then simulated in OpenSees software to perform nonlinear dynamic analysis. Twenty natural ground motion sequences each including two seismic events were selected from previous studies for the purpose of nonlinear incremental dynamic analysis. Maximum inter-story drift was employed as a damage index, to capture the performance of the RC frames under sequences. The accepted performance level for collapse level was taken from Iranian instruction for seismic rehabilitation of existing buildings, PBO-Publication No. 360, 2007, which is similar to ASCE 41-13. Seismic fragility values are calculated for the buildings under the second event when being damaged in first event. Assuming a log-normal distribution for failure probability function, corresponding values of median, μ and standard deviation, β, for each case are calculated and discussed for frames with different heights. The results indicate how the main parameters of the seismic fragility function may differ with frame height.

This paper presents a framework for enhancing building seismic resilience through a proposed appendix to the Iranian National Building Code (Standard 2800). The framework introduces three primary strategies: repairable structural systems, enhanced design requirements, and consequence-based design with lifecycle risk management. Analytical and experimental evidence support the effectiveness of these strategies in achieving multiple performance objectives, including minimized post-earthquake recovery time, reduced repair costs, and improved building performance beyond current code requirements. The proposed methodology integrates technical, economic, and social considerations through a multi-criteria decision-making approach, supported by lifecycle cost analysis and performance-based engineering principles. As the concept of seismic resiliency will be the first time to be addressed in the code, the main challenge was selecting the main pillars that should be considered.  The proposed guidelines aim to minimize post-earthquake recovery time, reduce repair costs, and improve overall building performance beyond current code requirements of the Standard 2800. This approach integrates technical, economic, and social considerations to achieve optimal seismic resilience.

The current Iranian Seismic Code, for seismic loading and analysis of structures, (Standard no.2800) considers linear elastic analysis to be adequate for structural and seismic response prediction for a majority of structures.In this regulation, an importance factor, I, is considered to improve the performance of buildings based on their importance. Linear analysis is inadequate for observing structural performance during earthquakes, because proper seismic behavior and the stability of structures are not just governed by strength; structures need to resist determined amounts of force and should be able to displace determined amounts of displacements. On this basis, it is expected that by using importance factor, I, in linear analysis, the structures will behave properly, and after earthquakes, will present a desired level of performance.New seismic regulations, such as FEMA 356 and the Iranian Seismic Rehabilitation Guideline, use a performance-based design method; nonlinear analysis methods are the main tools of these codes. Also, the main objective of this research is to evaluate the seismic performance of buildings, with different importance levels, designed according to the Iranian Seismic Code, using the Iranian Seismic Rehabilitation Guideline.In this research, a set of structures, with different categories of occupancy and different numbers of stories, are designed according to the Iranian Seismic Code. The seismic performance levels of the mentioned structures are evaluated using nonlinear static analysis (pushover), based on the Iranian Seismic Rehabilitation Guideline.The results show that the low- and medium-rise buildings behave to a life safety (LS) performance level. In high-rise buildings, with medium importance, the required performance level (LS) is not achieved, and in very high importance (essential) buildings, the required performance level (IO) is not achieved. Therefore, increasing the importance factor, I, does not necessarily lead to improvement in performance levels, but leads to an increase in structural weight; this could be a noneconomic decision. By using non-linear analysis in parts of the structure, in which performance level is not met, the structure would be strengthened and achieve the required level of performance.

In this paper, efforts are made to compare the safety of steel moment resistant frames designed according to different editions of the Iranian code of Practice for seismic resistant design of buildings. Also, failure risk of a low and medium height frame which designed for high and low seismicity regions according to three editions of the code are evaluated. First, the testing cases were designed and based on a simplified method the fragility functions of frames were evaluated. The probability of failure of frames was calculated by multiplying the fragility function and hazard curves in probabilistic manner. The results indicate that, apart from some exceptions, every edition of new code pro-vides better safety for structures. However, within a single version of the code, the consistency of safety has not been maintained. The structures designed for low seismicity regions are more reliable than those which designed for high seismicity regions. Further research should address this issue and fix the possible.

This paper examines differences in performances of a range of torsionally stiff and flexible single story buildings designed with the provisions of Iranian Standard 2800. Seismic nonlinear dynamic time history behavior of eight building models subjected to seven horizontal bi-directional design spectra compatible ground motions are investigated. These models cover a wide range of very torsionally stiff to very flexible buildings. Response parameters are element ductility demand and building story drift ratio. These criteria are appropriate indices for structural and nonstructural damages, respectively. This investigation shows that the linear static analysis of building code such as Iranian Standard 2800 is not generally adequate for structures with very low torsional stiffness.

This paper presents a study on the selection of engineering demand parameters (EDPs) for the definition of collapse forcode-conforming reinforced concrete buildings. The definition of collapse for buildings is not unique, as different codesand authors define it with respect to different EDPs and different values of the EDPs. Since collapse is associated with largeplastic deformations, collapse is typically defined by deformation, displacement, and eventually energy EDPs. The EDPscan be either local when they refer to a single structural element response parameter (such as element rotation with respectto the chord) or global when they refer to an overall building response parameter (such as inter-story drift or top floor displacement). The Italian buildings code NTC2008 and Eurocode 8 use the chord rotation as EDP, while FEMA 356 and otherNorth American literature use inter-story drift ratio. This study compares different definitions of EDPs and different valuesof the selected EDPs by analyzing two code-conforming benchmark buildings, one six-story and the other nine-story high, designed according to Italian code. Multiple-stripe, non-linear dynamic analyses are carried out on the two buildings modeledwith concentrated hinges. The results show that different collapse definitions lead to very different safety evaluationsand point to the need for the definition of a single EDP and a single value to make collapse analyses (and risk assessment)studies comparable.