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FEMA P695 methodology for safety margin evaluation of steel moment resisting frames subjected to near-field and far-field records

Mahdi Heshmati, Alireza Khatami, Hamzeh Shakib
Journal PapersSN Applied Sciences , Volume 3 , Issue 2, 2021 February , {Pages 21-Jan }

Abstract

This study presents the impact of near-field and far-field earthquakes on the seismic design of Intermediate Moment Resisting Frame (IMRF) and Special Moment Resisting Frame (SMRF) structures through FEMA (Federal Emergency Management Agency) P695 methodology to highlight the importance of probabilistic collapse as well as seismic performance factors of these structures. The purpose of this study is to investigate the collapse performance of steel intermediate and special moment resisting frame systems as the most common structural systems in urban areas in order to assess the seismic performance factors used for the design using nonlinear static and dynamic analysis methods. In this regard, as the representatives of low-rise

On the optimal performance-based seismic design objective for steel moment resisting frames based on life cycle cost

M Khalilian, H Shakib, MC Basim
Journal Papers , , {Pages }

Abstract

Seismological Aspects and Seismic Behavior of Buildings During the M 7.3 Western Iran Earthquake in Sarpol-e-zahab Region

H Shakib, S Dardaei, H Farhangian, NE Torkanbouri
Journal Papers , , {Pages }

Abstract

Masonry Dome Behavior under Gravity Loads Based on the Support Condition by Considering Variable Curves and Thicknesses

A Sharbaf, M Bemanian, K Daneshjoo, H Shakib
Journal Papers , , {Pages }

Abstract

Optimal Performance-Based Configurations of Stiffness and Strength Centers in Multi-Story Wall-Frame Asymmetric Buildings Including Soil–Structure Interaction Effects

S Mohammadzadeh Osalu, H Shakib, G McClure
Journal Papers , , {Pages }

Abstract

Masonry Dome Behavior under Gravity Loads Based on the Support Condition by Considering Variable Curves and Thicknesses. Buildings 2021, 11, 241

A Sharbaf, M Bemanian, K Daneshjoo, H Shakib
Journal Papers , , {Pages }

Abstract

Numerical simulation of seismic collapse mechanisms of vertically irregular steel high-rise buildings

Reza Ramezani Azghandi, Hamzeh Shakib, Maedeh Zakersalehi
Journal PapersJournal of Constructional Steel Research , Volume 166 , 2020 March 1, {Pages 105914 }

Abstract

The effect of mass and stiffness vertical irregularities on the collapse mechanism and resistance of steel high-rise structures is investigated using 3-D numerical simulations. Simulations are carried out utilizing a verified modelling approach in which the collapse processes of a regular and four irregular structures are studied under 11 earthquake records. It is indicated that the utilized finite element model, related considerations and calibrations present a reliable and efficient technique for collapse simulation. The findings show that vertical irregularities adversely affect the collapse resistance and mechanism of steel high-rise buildings. Especially, mass vertical irregularity with concentration in the lower half of the structure

Reliability-based seismic evaluation of buried pipelines subjected to earthquake-induced transient ground motions

Vahid Jahangiri, Hamzeh Shakib
Journal PapersBulletin of Earthquake Engineering , 2020 April 30, {Pages 25-Jan }

Abstract

In this research the effect of diameter to thickness of pipe ratio (D/t), depth of burial to diameter (H/D) ratio, conditions of surrounding soil and different grades of steel on the seismic answer of straight buried steel pipelines is investigated within a probabilistic context. The results of incremental dynamic analysis of 15 pipeline models are used to evaluate the capacities of performance limit, the mean annual frequency (MAF) of exceeding structural limit states and levels of confidence of achieving seismic performance goals. It is obtained that for the pipes with the ratios of D/t over 39.9, increasing the ratio of D/t decreases the IM capacity, increases MAF of exceeding the performance objectives and reduces the confidence level

Structural Global Performance Assessment Versus Individual Element-Oriented Performance-Based Assessment

Ebrahim Fadaei, Hamzeh Shakib, Alireza Azarbakht
Journal PapersIranian Journal of Science and Technology-Transactions of Civil Engineering , 2020 May 12, {Pages }

Abstract

In this paper, three new performance indices are proposed which can be used in order to determine the global performance of a given structure. The ASCE41-13 standard and the FEMA350 guidelines are used as representatives of, respectively, an element-oriented and a system-oriented performance-based assessment algorithm. Two ten-storeyed special steel moment frames, consisting of a regular and an irregular structure, are designed and assessed using these two algorithms. The results show that the element-oriented assessment algorithm significantly underestimates the seismic demand and capacity, especially in the case of the immediate occupancy and collapse prevention limit states. This underestimation can cause a significant drop in the estima

Hysteretic behavior of link beams with different cross-sections and stiffener arrangements

Samira Ebrahimi, Hamzeh Shakib, Masoud Soltani, Seyed Mehdi Zahrai
Journal PapersJournal of Constructional Steel Research , Volume 170 , 2020 July 1, {Pages 106084 }

Abstract

In conventional engineering practice, the use of stiffeners and flanges on both faces of stiffened web panels for I-shaped link beams provides fully restrained boundary conditions. In tubular link beams, however, the stiffened web panels possess simply supported boundary conditions due to the use of single-sided stiffeners and flanges.This study investigates the boundary condition effects of stiffened web panels in tubular and I-shaped link beams on their rotation capacity assuming similar area, moment of inertia, length and stiffener spacing. Based on the numerical results, I-shaped link beams demonstrated an approximately 78% higher rotation capacity compared to tubular link beams under the same conditions which could be due to the better

Seismic performance assessment of tubular diagrid structures with varying angles in tall steel buildings

Mahdi Heshmati, Alireza Khatami, Hamzeh Shakib
Journal PapersStructures , Volume 25 , 2020 June 1, {Pages 113-126 }

Abstract

Diagrid system has emerged as an innovative structural system with an aesthetic view in the design of tall buildings. In this study, seismic performance of 36-story diagrid structures with varying angles are evaluated using pushover and nonlinear time history analysis. Furthermore, in order to evaluate the effect of diagrid core on behavior of structures, interior gravity frames are replaced with diagrid frames. The results of pushover analyses demonstrate that diagrid core can enhance the hardening behavior of structures when the angles of perimeter panels are lower or equal than those of the core compared to the conventional diagrids. In addition, core diagrids provide safe margins between the damage states under lateral loading. Nonlinea

The Effect of Foundation Flexibility on Probabilistic Seismic Performance of Plan-Asymmetric Buildings with Different Strength Distributions

Sahar Mohammadzadeh Osalu, Hamzeh Shakib
Journal PapersAdvances in Civil Engineering , Volume 2020 , 2020 August 5, {Pages }

Abstract

In this research, the probabilistic seismic performance of asymmetric reinforced concrete wall-frame buildings with different strength distributions incorporating foundation flexibility effects is examined. By using probability-based performance evaluation approach, it is possible to provide a more accurate prediction of the different strength distribution effect on the seismic performance of asymmetric buildings and find the most efficient strength distribution for meeting each performance level. These efficient distributions can be adopted in the performance-based design of asymmetric buildings. For this purpose, first, the regression analysis and the concepts of efficiency and sufficiency were used to determine an optimal intensity measu

Evaluation of Plasco Building fire-induced progressive collapse

Hamzeh Shakib, Maedeh Zakersalehi, Vahid Jahangiri, Reza Zamanian
Journal PapersStructures , Volume 28 , 2020 December 1, {Pages 205-224 }

Abstract

This paper presents a comprehensive structural assessment of the fire-induced progressive collapse of Plasco Building, in January 2017. The assessment employs a three-phase approach: a) field investigation to collect data about the building and the event, b) structural evaluation against service loads, c) progressive collapse analysis. A collapse scenario is proposed, which is simulated using finite element modelling and numerical analysis. The results showed the adequacy of the building for service loads, while its significant vulnerability against progressive collapse. The vulnerability was mainly due to the lack of adequate continuity, ductility, and redundancy to resist the spread of damage. The weakest link in the structural system was

Development of Rocking Isolation for Response Mitigation of Elevated Water Tanks under Seismic and Wind Hazards

Hassan Alemzadeh, Hamzeh Shakib, Mohammad Khanmohammadi
Journal PapersShock and Vibration , Volume 2020 , 2020 October 5, {Pages }

Abstract

Elevated water tanks are categorized as strategic components of water supply systems in modern urban management. Past earthquake events have revealed the high vulnerability of these structures. This paper investigates the development of rocking isolation (RI) to these structures as a response mitigation technique. Using an analytical approach, a dynamic model is developed for two isolation cases: (1) at the pedestal base and (2) under the tank. The model incorporates a simplified analogy for simulating the liquid-tank system which is modified for a tank under rocking motions. Based on the dynamics of rocking structures, the equations of motion, impact, and uplift transitions are derived. Then, free vibration and seismic response history ana

Correlation of spectral acceleration values in Iranian ground motions

Rezvan Moaddab, Vahid Jahangiri, Hamzeh Shakib
Journal PapersJournal of Earth System Science , Volume 129 , Issue 1, 2020 December , {Pages 14-Jan }

Abstract

Spectrum compatibility is commonly used as a tool for ground motion record selection in order to perform dynamic analysis. Conditional mean spectrum calculation, which can be used as a target spectrum, requires obtaining correlation coefficients between spectral acceleration values at multiple periods. To date, the correlation coefficients have not been evaluated exclusively from ground motions recorded in Iran. This study represents results obtained from the calculation of correlations for spectral acceleration values from Iranian ground motion data and Zagros and Alborz-central Iran seismic regions, separately. The obtained results can be used for conditional mean spectrum calculations at Iranian sites. The observed correlation coefficien

VULNERABILITY EVALUATION OF BURIED STEEL PIPELINES UNDER SEISMIC WAVE PROPAGATION

V Jahangiri, H Shakib
Journal PapersSharif Journal of Civil Engineering , Volume 34 , 2019 February 20, {Pages 79-89 }

Abstract

{Lifelines are essential for human life and economic development. Buried steel pipelines are the sort of lifelines that their strength under extreme events, such as earthquakes, is very essential. One of the causes of failure of buried pipelines is seismic wave propagation. Buried steel pipelines are vulnerable in extreme events such as earthquakes. In this study vulnerability of buried steel pipelines was evaluated using the results of incremental dynamic analysis (IDA). Several IDA analyses of three buried steel pipe models with a different diameter to thickness and burial depth to diameter ratios and different soil properties, were performed using far-field earthquake ground motion records. The models were designed based on American Life

Reduction of shear lag and improvement of performance in tubular structures

Hamed Farhangian, Hamzeh Shakib
Journal PapersModares Civil Engineering journal , Volume 19 , Issue 5, 2019 December 10, {Pages 0-0 }

Abstract

The tubular structures are having the capability of resisting wind and earthquake loads with the exterior tube system. Tube systems consist of closely spaced exterior columns and deep beams around the corner of the plan that provides sufficient rigidity and stability for tall/high-rise buildings. Another advantage of the tubular system is the significant reduction in the building materials and increasing the architectural space in the internal plan. The mentioned cases have increased the popularity of this kind of structural system. But the most important problem in the tube system is the shear lag. Shear lag is the non-uniform distribution of stress on the face columns when the tube system is subjected to lateral loads. Shear lag can occur

SEISMIC PERFORMANCE OF DUAL STEEL STRUCTURES CONSISTING OF NON-GEOMETRICAL IRREGULARITY ALONG THE HEIGHT

E FADAEI, H SHAKIB, A AZARBAKHT
Journal Papers , Volume 352 , Issue 3200820, 2019 January 1, {Pages 107-120 }

Abstract

The effects of irregularities along the height of structure on the basis of mass, stiffness, strength, and the combination of stiffness-strength are investigated in this study by means of dual steel structures consisting of special steel moment frame and special concentric braced frames. The Performance-based earthquake engineering has been implemented in the form of probabilistic confidence level by means of incremental dynamic analysis in order to obtain seismic demand and capacity. A set of ten-storeyed steel moment frames is taken into consideration with different irregularity cases along the height of structure. All considered structures are first carefully designed based on 4th edition of the Iranian practice for seismic-resistance de

SEISMIC PERFORMANCE OF DUAL STEEL STRUCTURES CONSISTING OF NON-GEOMETRICAL IRREGULARITY ALONG THE HEIGHT

E Fadaei, H Shakib, AR Azarbakht
Journal PapersSharif Journal of Civil Engineering , Volume 35 , Issue 3.2, 2019 November 22, {Pages 107-120 }

Abstract

The effects of irregularities along the height of structure on the basis of mass, stiffness, strength, and the combination of stiffness-strength are investigated in this study by means of dual steel structures consisting of special steel moment frame and special concentric braced frames. The Performance-based earthquake engineering has been implemented in the form of probabilistic confidence level by means of incremental dynamic analysis in order to obtain seismic demand and capacity. A set of ten-storeyed steel moment frames is taken into consideration with different irregularity cases along the height of structure. All considered structures are first carefully designed based on 4th edition of the Iranian practice for seismic-resistance de

Seismic risk assessment of buried steel gas pipelines under seismic wave propagation based on fragility analysis

Vahid Jahangiri, Hamzeh Shakib
Journal PapersBulletin of Earthquake Engineering , Volume 16 , Issue 3, 2018 March 1, {Pages 1571-1605 }

Abstract

In this paper economic seismic risk analysis of API 5L buried steel gas pipelines is carried out through incremental dynamic analysis using an ensemble of 20 ground motion records. Multiple performance limit states for buried steel pipelines are proposed. Fragility curves of 15 pipeline models of various diameter to thickness (D/t) ratios, burial depth to diameter (H/D) ratios, assumed soil conditions and steel grades are plotted for damage states corresponding to the defined limit states. Expected global economic loss of 1?km length of the pipelines for a given peak ground velocity is obtained using the fragility curves, a pipeline repair ratio as well as costs of leakage repairing and break-induced pipe replacement. The mea

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