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, M.Sc. Thesis Sharif University of Technology ; Moghaddam, Hassan (Supervisor)
Abstract
The paper presents the results nonlinear analysis of steel base plates subjected to different combinations of axial and bending forces. The bending forces range from small moments representing small eccentricities to large moments from seismic actions. The results of analyses proved to be in good agreement with experiments. The parameters investigated in this study are as follows: distribution of strain and stresses in the concrete foundation and the steel plate, the strains and stresses in the tensile anchorage bolts, the location of neutral curve under the base plate, the centre of compressional reaction forces in concrete, the flextural rigidity of the base plate connection, and the axial...
Investigation of damages in RC frames under near field earthquakes using a damage index
, Article International Journal of Structural Stability and Dynamics ; Volume 16, Issue 2 , 2016 ; 02194554 (ISSN) ; Kazemi, M. T ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
Abstract
Heavy damages on structures caused by near field earthquakes in recent years has brought serious attention to this problem. An examination of previous records has shown significant differences for near field earthquakes, including a large energy pulse, unlike far field earthquakes. But as a general rule, the effects of near field earthquakes have been ignored in most building codes. The purpose of this paper is to investigate the effect of near field earthquakes on reinforced concrete (RC) moment frames. To achieve this goal, the Erduran damage index, an efficient way to calculate damage, was employed to analyze two 4- and 8-story RC moment frame buildings. The buildings with moderate and...
Force-displacement model for solid confined masonry walls with shear-dominated failure mode
, Article Earthquake Engineering and Structural Dynamics ; Volume 46, Issue 13 , 2017 , Pages 2209-2234 ; 00988847 (ISSN) ; Bakhshi, A ; Ghannad, M. A ; Sharif University of Technology
Abstract
This paper addresses the behavior of confined masonry walls with dominating shear failure mode in walls. For this purpose, failure modes of these walls are classified in details. For each failure mode, complete set of analytical-based relations for deriving parameters related to backbone curves is introduced. Calibrated finite element analyses are utilized as a benchmark for verification of some of the assumptions. The results of the proposed relations are compared with those of several Iranian and non-Iranian experimental data. Sensitivity analysis is performed in order to understand the effects of important behavioral characteristics of these walls. The results of this study indicate that...
Compatibility of the endurance time method with codified seismic analysis approaches on three-dimensional analysis of steel frames
, Article Structural Design of Tall and Special Buildings ; Volume 22, Issue 2 , 2013 , Pages 144-164 ; 15417794 (ISSN) ; Estekanchi, H. E ; Sharif University of Technology
2013
Abstract
The endurance time (ET) method is a time history-based dynamic pushover analysis procedure that utilizes special intensifying acceleration functions for estimating the seismic performance of structures at different excitation levels. One of the potential applications of the ET method is in the three-dimensional analysis of buildings considering multidirectional excitation. In this paper, a procedure for multi-component analysis by the ET method has been developed. Several steel moment frames with heights from 9.6 to 48 m were designed according to the Iranian National Building Code. By applying the proposed algorithm for three-dimensional analysis of structures by the ET method, these frames...
Characteristics of second generation endurance time acceleration functions
, Article Scientia Iranica ; Volume 17, Issue 1 A , 2010 , Pages 53-61 ; 10263098 (ISSN) ; Estekanchi, H. E ; Vafai, A ; Sharif University of Technology
Abstract
The Endurance Time (ET) method is a time-history based dynamic pushover procedure in which structures are subjected to specially designed, intensifying accelerograms, and their seismic performance is judged based on the time duration needed to satisfy the required design objective. Second generation refers to ET acceleration functions that are generated by application of optimization techniques in order to produce response spectra compliant linearly intensifying accelerograms. In this paper, the major characteristics of a set of second generation ET acceleration functions (ETA20a01-3) are investigated. The template response spectra of this set of ET acceleration functions corresponds to the...
Optimum seismic design of steel framed-tube and tube-in-tube tall buildings
, Article Structural Design of Tall and Special Buildings ; Volume 29, Issue 14 , 2020 ; Estekanchi, H. E ; Moosavian, H ; Sharif University of Technology
John Wiley and Sons Ltd
2020
Abstract
The relatively large number of structural elements and the variety of design code requirements complicate the design process of tall buildings. This process is exacerbated when the target is to obtain the seismic code-compliant optimal design with minimum weight. The present paper aims at providing a practical methodology for the optimal design of steel tall building structures considering the constraints imposed by typical building codes. The applicability of the proposed approach is demonstrated through the determination of the optimal seismic design for 20-, 40-, and 60-story buildings with a framed tube as well as a tube-in-tube system. Such a design gives rise to a basis for the fair...
Passive cooling effects of courtyards
, Article Building and Environment ; Volume 40, Issue 1 , 2005 , Pages 89-104 ; 03601323 (ISSN) ; Bahadori, M. N ; Sharif University of Technology
2005
Abstract
The passive cooling effects of a courtyard of a small building were determined numerically, employing an energy-analysis software developed for that purpose. The passive cooling features considered were the shading effects of courtyard walls and two large trees (of various shapes) planted immediately next to the south wall of the building, the presence of a pool, a lawn and flowers in the yard, and the wind shading effects of the walls and trees. It was found that these features alone cannot maintain thermal comfort during the hot summer hours in Tehran, but reduce the cooling energy requirements of the building to some extent. They have an adverse effect of increasing the heating energy...
Evaluation of the seismic performance factors for steel diagrid structural systems using FEMA P-695 and ATC-19 procedures
, Article Bulletin of Earthquake Engineering ; Volume 18, Issue 10 , 2020 , Pages 4873-4910 ; Seyedkazemi, A ; Sharif University of Technology
Springer
2020
Abstract
The diagrid structural systems are mainly used for their structural capabilities and architectural aesthetic possibilities which are provided by the unique geometric configurations of these systems. However, the seismic performance factors of these structural systems are not yet explicitly recommended in the existing building codes. In this study, the seismic performance factors (SPFs) of 6- to 24-story steel diagrid structures are determined considering the post-buckling behavior of diagonal members in compression. Also, the effect of change in span length and the diagonal angles on the SPFs of diagrid structures is studied. The ATC-19 coefficient method is used for calculating the SPFs...
Evaluation of the vertical distribution of base shear force in base-isolated structures
, Article Scientia Iranica ; Volume 14, Issue 1 , 2007 , Pages 11-22 ; 10263098 (ISSN) ; Ebrahimi, M ; Sharif University of Technology
Sharif University of Technology
2007
Abstract
Application of the base-isolation systems, as a means to limit the seismic-induced response of structures, has attracted the attention of many engineers and researchers. Due to their importance, the Uniform Building Code (UBC) has incorporated a special section for the seismic analysis and design of base-isolated structures since its 1991 edition. The present work investigates the vertical distribution of the lateral seismic force for base-isolated structures provided by the 1997 edition of UBC (UBC97). Different 6 and 8-story, 3-D base-isolated structural models with LRB isolators are considered, having a variety of effective periods and effective damping ratios. The UBC97 analysis...
Seismic damage and life cycle cost assessment of unanchored brick masonry veneers
, Article Engineering Structures ; Volume 260 , 2022 ; 01410296 (ISSN) ; Ghahremani Baghmisheh, A ; Estekanchi, H. E ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This paper develops the seismic damage models of brick masonry veneer attached to the masonry infill without metal ties and assesses the life cycle cost of veneers subjected to earthquake excitation. Even though anchoring veneers to the backup wall has been prescribed in recent building codes, most of the existing brick veneers in seismic prone areas around the world lack the anchoring details. Besides, the damage and consequence models of masonry façades have not been presented in the FEMA-P58 database restricting detailed performance evaluation of buildings with unanchored masonry veneers. This study develops detailed finite element models to simulate various failure modes of the masonry...
Determining shear capacity of ultra-high performance concrete beams by experiments and comparison with codes
, Article Scientia Iranica ; Volume 26, Issue 1A , 2019 , Pages 273-282 ; 10263098 (ISSN) ; Joghataie, A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the...
Determining shear capacity of ultra-high performance concrete beams by experiments and comparison with codes
, Article Scientia Iranica ; Volume 26, Issue 1A , 2019 , Pages 273-282 ; 10263098 (ISSN) ; Joghataie, A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the...
A Performance-Based Approach to the Design of Shallow Foundations Resting on Heterogeneous Subsoil Prone to Liquefaction Hazards
, Article 4th Geo-China International Conference: Innovative Technologies for Severe Weather and Climate Change, Geo-China 2016, 25 July 2016 through 27 July 2016 ; Volume 2016-January, Issue 264 GSP , 2016 , Pages 47-55 ; 08950563 (ISSN) ; Ayoubi, P ; Shahir, H ; El-Badawy S ; Cheng D ; Arab M ; Chinese National Science Foundation; Geo-Institute (G-I) of the American Society of Civil Engineers (ASCE); Shandong Department of Transportation; Shandong University; University of Oklahoma ; Sharif University of Technology
American Society of Civil Engineers (ASCE)
2016
Abstract
Performance-based design (PBD) has become increasingly important in recent years, especially for the design of foundations rested on sub-soils that are susceptible to liquefaction at seismically active areas. Shallow foundations may fail due to excessive settlement because of liquefaction of the underlying loose saturated cohesion-less sands. Building codes usually do not address the issue of liquefaction-induced settlement of shallow foundations. In this paper, a framework is proposed for calculating the liquefaction-induced settlement of shallow foundations resting on heterogeneous two-layered liquefiable soil by conducting a series of 3D. hydro-mechanical dynamic analyses in a fully...
Ramifications of blind adoption of load and resistance factors in building codes: reliability-based assessment
, Article Bulletin of Earthquake Engineering ; Volume 19, Issue 2 , 2021 , Pages 963-986 ; 1570761X (ISSN) ; Mahsuli, M ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
This paper presents a probabilistic approach to reveal the negative consequences of overlooking code calibration when adopting the provisions of nonindigenous building codes in design. A taxonomy of the national building codes of various countries whose provisions are adopted from one or more original standards is first presented. Next, the reliability-based approach to quantify the lack of safety that may arise due to the absence of code calibration is presented. This approach is then applied to the case study of the National Building Code of Iran, whose load and resistance factors are directly adopted from ASCE/SEI 7. To this end, seven steel building archetypes with various structural...
Influence of different seismic retrofit methods on fragility curves of an existing RC frame
, Article ISEC 2011 - 6th International Structural Engineering and Construction Conference: Modern Methods and Advances in Structural Engineering and Construction ; 2011 , Pages 995-1000 ; 9789810879204 (ISBN) ; Pour, M.T ; Yazdani S ; Cheung S. O ; Singh A ; Ghafoori N ; American Society of Civil Engineers (ASCE); Architectural Institute of Japan (AIJ); Chartered Institute of Building (CIOB); et al.; University of Nevada Las Vegas (UNLV), College of Engineering; Wayne State College of Engineering ; Sharif University of Technology
Abstract
One of the main challenges in earthquake risk mitigation nowadays is the seismic performance assessment of existing buildings that were not designed according to modern building code standards and the development of effective techniques to retrofit these structures. In this paper seismic performance of an existing 5-story RC frame building which is typical building stock in central region of Tehran retrofitted by three methods (Concrete jacketing, Steel jacketing, CFRP wrapping) is investigated by developing fragility curves. Corresponding Fragility curves are constructed for three structural damage limit states, collapse prevention (CP), Life Safety (LS) and immediate occupancy (IO) and...
Providing a methodology to codify regulations for private parking in tehran city
, Article International Conference on Transportation and Development 2016: Projects and Practices for Prosperity, 26 June 2016 through 29 June 2016 ; 2016 , Pages 353-364 ; 9780784479926 (ISBN) ; Nickkar, A ; Ghadiri, M ; The Transportation and Development Institute (T and DI) of the American Society of Civil Engineers (ASCE) ; Sharif University of Technology
American Society of Civil Engineers (ASCE)
2016
Abstract
One of the methods for providing private parking is to use the mechanized parking within neighborhoods or housing units that are common in today's world. But, unfortunately, due to lack of appropriate rules and technical, administrative and legal guidelines, this approach has not yet been used. Hence the necessity of investigating and formulating laws, programs and specific criteria for mechanized private parking in terms of legal, technical, traffic, urbanization aspects (location, neighborhood, architecture, building standards and national regulations, economic aspects, etc.) have been a motivation for conducting this study. In this research, after studying and investigating previous...
Seismic performance of an innovative structural system having seesaw motion and columns equipped with friction dampers at base level
, Article Structural Design of Tall and Special Buildings ; 2016 ; 15417794 (ISSN) ; Fekri, M ; Yekrangnia, M ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
Most seismic design codes accept heavy damages to buildings in case of large earthquakes, provided that they are prevented against collapse. However, this leads to unacceptable consequences, such as very large volume of the required reconstruction works, in large populated cities. One way to get rid of these adverse consequences is using the idea of combining rocking/seesaw motion of the building's structure and energy dissipation at base level to create buildings easily repairable even after a large earthquake. In the present study, this idea has been employed for designing steel buildings with seesaw motion capability by using a central massive column at ground floor, with elastic behavior...
Uncertainty quantification in seismic collapse assessment of the Iranian code-conforming RC buildings
, Article Scientia Iranica ; Volume 27, Issue 4 , 2021 , Pages 1786-1802 ; 10263098 (ISSN) ; Ghaemian, M ; Hariri Ardebili, M. A ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
Abstract. Structural collapse is the main concern for the existing structures which are built in the seismic-prone regions. Therefore, the primary goal of the seismic provisions in building codes is to prevent the global collapse. Iran is located in the Alpine-Himalayan belt, and has experienced some of the most destructive earthquakes in the past century. To evaluate the extent to which the Iranian building code provisions meet the abovementioned objective, the authors conducted a detailed assessment of collapse risk on a set of moderate moment resisting Reinforced Concrete (RC) buildings. While many features might affect the seismic performance of the RC structures, this study considers...
Shaking table and analytical study of a brick masonry building with confined walls
, Article 10th East Asia-Pacific Conference on Structural Engineering and Construction, EASEC 2010, Bangkok, 3 August 2006 through 5 August 2006 ; Volume 3 , 2006 , Pages 267-272 ; 9748257231 (ISBN); 9789748257235 (ISBN) ; Kazemi, M. T ; Sharif University of Technology
2006
Abstract
A single storey full-scale unreinforced brick masonry building with confined walls was designed based on Iranian building code and constructed on the shaking table facility of EERC of Sharif University of Technology. The model consisted of plain brick masonry walls confined with concrete tie columns and steel bond beams and had a typical jack-arch roof system. Wall panels included openings of different dimensions making it possible to investigate the effects of shape, geometry and location of openings. The model was subjected to several seismic excitations, consisting of scaled records of Bam 2003, Tabas 1978 and Elcentro 1940 earthquakes as well as a harmonic acceleration with a gradually...
Considering rupture directivity effects, which structures should be named 'long-period buildings'?
, Article Structural Design of Tall and Special Buildings ; Volume 22, Issue 2 , 2013 , Pages 165-178 ; 15417794 (ISSN) ; Khaloo, A. R ; Sharif University of Technology
2013
Abstract
Recorded accelerograms in the regions near active faults may have specific characteristics that inclusion of their effects on the response of structures is necessary. Of particular importance are permanent displacement, i.e. fling-step, rupture directivity pulses and high-frequency content. Several researchers have focused on the effects of rupture directivity pulses on response of structures. They have shown that long-period structures are severely affected by these types of excitations. However, in near-fault regions, the question 'which building structures are long period?' has not been clearly and quantitatively answered. In this paper, responses of 10-, 20-, 30- and 40-story steel...