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Prediction of target displacement in structural systems plays a significant role in performance-based design and rehabilitation of structures. In this study, the γ factor for different hardening ratios, including 1, 2, 3, 5, 7.5, 10, and 15 percentages, stiffness-strengthdeterioration models, and soil type classes is determined to modify the energy balance equation in performance-based plastic design (PBPD). Statistical results indicate that the effect of the hardening ratio, deterioration, and soil type class on the capacity curve is considerable. Therefore, a simple equation based on the period of the vibration and ductility is suggested to estimate the γ factor in different structural systems. Moreover, four 1-, 3-, 7-, and 12-story moment steel structures with various hardening ratios in the material are designed to validate the proposed method. The suggested values for the γ factor show exact results compared to collected displacements from time history analysis, while the error in the previous work was considerable. Statistical results showed that the mean error in the previous method in estimating target displacement for 1-, 3-. 7-, and 12-story structures is about 15%, 20%, 20%, and 32%, respectively. Conversely, the mean error in this study for estimating target displacement of 1-, 3-. 7-, and 12-story structures is about 10%, 7%, 6%, and 15%, respectively. Finally, the proposed method is examined on the empirical reinforced concrete (RC) bridge pier simulated numerically with fiber-based modeling. Similarly, the suggested equation estimates the target displacement appropriately for the concrete model compared to achieved displacements from nonlinear dynamic analysis. [ABSTRACT FROM AUTHOR]

The adequacy of the structural performance of a wharf in withstanding seismic loads is of paramount importance. Therefore, this research aims to conduct an accurate pushover analysis on the adequacy of a wharf located in North Sulawesi, Indonesia. The study provides a comprehensive overview of the seismic performance of the wharf by examining displacement and strain parameters of its plastic hinge components under various loading conditions. To simulate accidental torsion, the wharf structure was analyzed by introducing variations in the eccentricity offset of the lateral pushover load of -5%, 0%, and 5% from the center of mass. The analysis of the torsion behavior involved a comprehensive examination of four control points located at each corner of the wharf plan. Additionally, the investigation took into account, the crucial aspect of soil-structure interaction by considering the equivalent fixity depth of the pile, which was used to evaluate the fixity length of the structure. In order to determine the target displacement of the wharf, analysis was performed in accordance with the established methodologies outlined in FEMA-356. It is also important to note that the seismic performance of the wharf was evaluated based on acceptance criteria in the form of strain limits imposed on various components, including concrete elements, reinforcing steel, and steel pipes, as prescribed by ASCE 61-14. In this study, a total of 30 models were examined, and the obtained results showed that the structure exhibited controlled and repairable damage even when subjected to a 475-year earthquake return period (CLE: Contingency Level Earthquake). Following this, the analysis of variations in displacement control point served to determine the inherent torsion exhibited by the structure, and the introduction of different lateral load eccentricity offsets and variations in pushover loading direction were found to contribute to the increased displacement and strain in the plastic hinge components. [ABSTRACT FROM AUTHOR]

The realistic determination of damage estimation and building performance depends on target displacements in performance-based earthquake engineering. In this study, target displacements were obtained by performing pushover analysis for a sample reinforced-concrete building model, taking into account 60 different peak ground accelerations for each of the five different stories. Three different target displacements were obtained for damage estimation, such as damage limitation (DL), significant damage (SD), and near collapse (NC), obtained for each peak ground acceleration for five different numbers of stories, respectively. It aims to develop an artificial neural network (ANN)-based sustainable model to predict target displacements under different seismic risks for mid-rise regular reinforced-concrete buildings, which make up a large part of the existing building stock, using all the data obtained. For this purpose, a hybrid structure was established with the particle swarm optimization algorithm (PSO), and the network structure's hyper parameters were optimized. Three different hybrid models were created in order to predict the target displacements most successfully. It was found that the ANN established with particles with the best position revealed by the hybrid models produced successful results in the calculation of the performance score. The created hybrid models produced 99% successful results in DL estimation, 99% in SD estimation, and 99% in NC estimation in determining target displacements in mid-rise regular reinforced-concrete buildings. The hybrid model also revealed which parameters should be used in ANN for estimating target displacements under different seismic risks. [ABSTRACT FROM AUTHOR]

Recycled aggregate concrete‐filled square steel tube (S‐RACFST) frame has the characteristics of high bearing capacity, good ductility, and superior seismic performance. To propose a displacement‐based seismic design of S‐RACFST frame, the validity of the design method was verified by a detailed calculation example. Based on the performance requirements, this design method divided the structural performance into five levels: normal use, temporary use, use after strengthening, life safety, and collapse prevention, and suggested specific steps for the displacement‐based seismic design of S‐RACFST frame using the inter‐story displacement angle limit value as the quantitative indicator. The 10‐story S‐RACFST frame was used as an analytical example for static elastic–plastic analysis. The pushover lateral displacement curves of the frame structure at each performance level were obtained and compared with the displacement‐based seismic design curves. The results show that the displacement‐based seismic design method of S‐RACFST frame structures can fulfill the performance level requirements such as "temporary use," "normal use," and "collapse prevention," and the displacement‐based seismic design method is one of the effective ways to realize the performance design of S‐RACFST frame structures. [ABSTRACT FROM AUTHOR]

The adequacy of the structural performance of a wharf in withstanding seismic loads is of paramount importance. Therefore, this research aims to conduct an accurate pushover analysis on the adequacy of a wharf located in North Sulawesi, Indonesia. The study provides a comprehensive overview of the seismic performance of the wharf by examining displacement and strain parameters of its plastic hinge components under various loading conditions. To simulate accidental torsion, the wharf structure was analyzed by introducing variations in the eccentricity offset of the lateral pushover load of -5%, 0%, and 5% from the center of mass. The analysis of the torsion behavior involved a comprehensive examination of four control points located at each corner of the wharf plan. Additionally, the investigation took into account, the crucial aspect of soil-structure interaction by considering the equivalent fixity depth of the pile, which was used to evaluate the fixity length of the structure. In order to determine the target displacement of the wharf, analysis was performed in accordance with the established methodologies outlined in FEMA 356. It is also important to note that the seismic performance of the wharf was evaluated based on acceptance criteria in the form of strain limits imposed on various components, including concrete elements, reinforcing steel, and steel pipes, as prescribed by ASCE 61-14. In this study, a total of 30 models were examined, and the obtained results showed that the structure exhibited controlled and repairable damage even when subjected to a 475-year earthquake return period (CLE: Contingency Level Earthquake). Following this, the analysis of variations in displacement control point served to determine the inherent torsion exhibited by the structure, and the introduction of different lateral load eccentricity offsets and variations in pushover loading direction were found to contribute to the increased displacement and strain in the plastic hinge components.

Data from past earthquakes is an important tool to reveal the impact of future earthquakes on engineering structures, especially in earthquake-prone regions. These data are important indicators for revealing the seismic loading effects that structures will be exposed to in future earthquakes. Five different earthquakes from six countries with high seismic risk were selected and were within the scope of this study. The measured peak ground acceleration (PGA) for each earthquake was compared with the suggested PGA for the respective region. Structural analyzes were performed for a reinforced-concrete (RC) building model with four different variables, including the number of storeys, local soil types, building importance class and concrete class. Target displacements specified in the Eurocode-8 were obtained for both the suggested and measured PGA values for each earthquake. The main goal of this study is to reveal whether the proposed and measured PGA values are adequately represented in different countries. We tried to reveal whether the seismic risk was taken into account at a sufficient level. In addition, target displacements have been obtained separately in order to demonstrate whether the measured and suggested PGA values for these countries are adequately represented in structural analysis and evaluations. It was concluded that both seismic risk and target displacements were adequately represented for some earthquakes, while not adequately represented for others. Comments were made about the existing building stock of the countries considering the obtained results. [ABSTRACT FROM AUTHOR]

The local soil conditions of the region where the structure is located are one of the important parameters taken into account in the evaluation and design of structures under the influence of earthquakes. In this study, the effect of different local soil conditions on target displacement values of reinforced-concrete (RC) structures in different seismic regions was investigated. For this purpose, four different settlements within each earthquake zone specified in the previous earthquake zone map were taken into account. Structural analyzes for a sample reinforced concrete structure using four different local soil conditions were performed for all residential units separately. The values predicted in the current earthquake hazard map for the considered locations were repeated for four different local soil classes. For the settlements, the predicted values in the last two maps were compared. As the soil properties improved as a result of the structural analysis, the displacement values predicted for the building performance level took lower values. [ABSTRACT FROM AUTHOR]

In this research, dynamic characteristics of 46 damaged or retrofitted buildings (22 RC and 24 steel buildings) induced by Sarpol-e Zahab earthquake are determined by ambient vibration tests. The obtained results are compared with the results of proposed empirical relations between codes and literature. Furthermore, empirical relations are proposed for calculation of fundamental periods of different types of buildings. In addition, damping ratios and mode shapes of buildings are obtained and presented. In the last section, target displacements of buildings are calculated using the experimental, analytical, and empirical periods and a thorough comparison is made between them. [ABSTRACT FROM AUTHOR]

In this study a timber-based integrated solution is presented to solve at once common issues affecting typical reinforced concrete (RC) existing buildings, such as seismic and energy performances, providing an eco-friendly alternative to steel external bracing systems. Cross-laminated timber (CLT) walls are provided perpendicularly to the external façades as strengthening elements while interposed CLT slabs are foreseen at each floor level to host new architectural units together with a new envelope. While the connections to the foundations and to the existing RC frames are provided respectively with steel brackets and axial-connectors distributed along the height of the building, a post-tensioned connection, between CLT panels (PT-CLT connection), is implemented in the system to guarantee resistance to horizontal actions acting parallel to existing façades with consequent structural independence and architectural freedom. On this regards a first look at the findings of an experimental campaign carried on the Technical University of Munich are presented. A numerical model is developed with finite element software characterizing each type of connector for linear and non-linear analyses. Modal analyses with response spectrum are performed to verify structural elements and connectors, while pushover analyses with target displacement checks are performed to assess the obtained seismic improvement. Finally, the preassembled architectural components that allow to renovate the envelope and the provided assembly procedure are revealed. [ABSTRACT FROM AUTHOR]

Significant loss of life and property has occurred as a result of many destructive earthquakes in both historical and instrumental periods in Turkey, which is located on the Alpine-Himalayan seismic belt. Past local earthquakes are an excellent tool to predict potential earthquakes in any region. Within the scope of this study, seismic parameters were obtained in the light of current data for a total of 62 earthquake epicenters with Ms ≥ 6 that occurred in the instrumental period in Turkey. Comparisons between seismic parameters were made on the last two earthquake hazard maps used in Turkey. In addition, the measured actual peak ground acceleration values for 16 earthquakes whose data can be accessed were compared with the current peak ground acceleration values as specified in the current Turkish Seismic Design Code. In order to compare the effectiveness of seismicity hazard map specified in previous and current Turkish Seismic Design Code, structural analysis of a reinforced-concrete building was carried out by using both the measured and current acceleration values according to the last two earthquake hazard maps. It has been determined that there are differences between the measured and proposed peak ground acceleration for some earthquakes. There are significant differences between the expected target structure displacement values as a result of structural analyses. [ABSTRACT FROM AUTHOR]

The nonlinear pushover analysis was used to evaluate an existing 8-storey reinforced concrete framed hospital building under seismic force and presented in this manuscript. The ‘Guru Teg Bahadur Hospital' is one of the important hospitals at Delhi-India, it was selected for this research. The three-dimensional frame model was used to model the building with a fixed base. The beams and columns were modeled by using three-dimension line frame elements with the centre lines joined at nodes. Diagonal strut elements were used to model the brick masonry infills. The slabs were considered as rigid diaphragms. The plastic hinge rotation capacities as per Federal Emergency Management Agency 356 (FEMA 356) with Performance Levels were adopted in this study, considering the axial force-moment and shear force-moment interactions. The nonlinear pushover analysis of the selected building was done with infills and it was observed that the infills (due to their small number in the considered building) do not make any appreciable effect on the performance level, except their failure at an early stage. The Capacity Spectrum Method (CSM) and Displacement Coefficient Method (DCM) were used to estimate the performance point of the building. The values of various coefficients as per Federal Emergency Management Agency 440 (FEMA 440) were adopted. The DCM was observed to give slightly higher target displacements, as compared to CSM. It was observed in the nonlinear pushover analysis that the unreinforced masonry (URM) infills collapse before the performance point of the building for the Maximum Considered Earthquake (MCE). As the intervention inside the functioning hospital is extremely difficult, it was explored whether it is possible to safeguard the infills by stiffening the building by providing external buttresses. Two cases of retrofitting schemes with 1.2m wide and 3m wide buttresses in transverse direction were used and analysed. It was found that this is not a practicable approach, as the infills collapse even with 3m wide buttresses.

Data from past earthquakes is an important tool to reveal the impact of future earthquakes on engineering structures, especially in earthquake-prone regions. These data are important indicators for revealing the seismic loading effects that structures will be exposed to in future earthquakes. Five different earthquakes from six countries with high seismic risk were selected and were within the scope of this study. The measured peak ground acceleration (PGA) for each earthquake was compared with the suggested PGA for the respective region. Structural analyzes were performed for a reinforced-concrete (RC) building model with four different variables, including the number of storeys, local soil types, building importance class and concrete class. Target displacements specified in the Eurocode-8 were obtained for both the suggested and measured PGA values for each earthquake. The main goal of this study is to reveal whether the proposed and measured PGA values are adequately represented in different countries. We tried to reveal whether the seismic risk was taken into account at a sufficient level. In addition, target displacements have been obtained separately in order to demonstrate whether the measured and suggested PGA values for these countries are adequately represented in structural analysis and evaluations. It was concluded that both seismic risk and target displacements were adequately represented for some earthquakes, while not adequately represented for others. Comments were made about the existing building stock of the countries considering the obtained results.

The current design philosophy for buildings located in zones with high seismic risks is that the buildings must have sufficient strength and stiffness to remain elastic and serviceable under moderate but frequently occurring earthquakes and to have sufficient ductility to prevent collapse under extreme earthquakes. Conventional structural steel framing systems such as moment resisting frames (MRFs), concentrically braced frames (CBFs), and eccentrically braced frames (EBFs) I extensively used in seismically active areas. Each of the previously mentioned structural systems has different advantages and disadvantages.In this study, response modification factor of ordinary inverted V-braced frames and specially inverted V-braced frames are evaluated, result confirm that the proposed height for buildings with ordinary inverted braced frames in the ASCE7,can be increased up to 10.7 meter. also results indicate that by using ordinary inverted V-bracing systems in buildings .their height can be increased up to 6 story or 20 meter. Using special inverted V-braced systems can have saving about 0 to 30 percent on used materials for frames from 1 story to 16 stories. According to the results of this study, response modification factor proposed by Iranian seismic design code (2800 standard fourth edition),(R=5.5), is more logical than the one which is proposed by ASCE7, (R=6). Unfortunately, in special inverted V-braced frames, and when the story of the frames increases up to 12 stories, ductility demand can't be achieved .So as a result for frames which are more than 12 stories tall, lower response modification factor should be used. In addition, frames taller than 12 story height don’t experience specified target displacement and collapse before getting to preferred mechanism. This phenomenon shows the necessity of using different response modification factor for frames taller than 12 stories.

A main challenge for performance-based seismic engineering is to develop simple, practical and precise methods for assessing existing structures to satisfy considerable performance objectives. Pushover analysis is a simplified nonlinear analysis technique that can be implemented for estimating the dynamic demands imposed on a structure under earthquake excitations. In this method, structure is subjected to specified load pattern to reach a target displacement. The present study provides a target displacement for estimating the seismic demand of eccentrically braced frames (EBFs). A parametric study is conducted on a group of 30 EBFs under a set of 15 accelerograms. The results of nonlinear dynamic analyses of EBFs have been post-processed by nonlinear regression analysis and a relation is proposed for target displacement. In order to verify the capability of the proposed procedure, three EBFs are assessed by the present method in which the results show that the proposed method is capable of reproducing the peak dynamic responses with relatively good accuracy. Additionally, the comparison of obtained results with those of other conventional target displacement methods such as N2 method, and displacement coefficient method confirms the efficiency of the suggested one.

The use of different methods of prestressing systems is very common in gravity frames at the present time. This technology can also be used in lateral load resisting frames. In addition to ordinary moment frames, this technology can be used in intermediate and special moment resisting frames. The use of post-tensioned prestressed slabs as primary members of the seismic load resisting load path in special moment resisting frames is not permitted based on available codes. The use of prestressed beams in special moment resisting frames includes some limitations. In this study, after the design of special prestressed moment frames with prestressed beams and slabs using conventional methods, considering special seismic design criteria, nonlinear pushover static analysis has been carried out in order to investigate performance levels and vulnerability of this type of frames. After performing nonlinear static analysis, target displacement of desired frames has been calculated and the plastic hinges formation sequence and related acceptance criteria for these hinges is investigated. Also, in order to study the effect of prestressing on seismic behavior of special prestressed moment resisting frames, response modification factor and related seismic parameters of this type of frames are obtained. Finally, all the above steps are repeated for the corresponding reinforced concrete special moment resisting frames, and the results were compared with prestressed frames. The obtained results show that in addition to applying restrictions on the use of prestressed beams in special moment resisting frames, target building performance levels and structural performance levels are acceptable, compared to reinforced concrete frames. Higher ductility factor and response modification factor has been achieved for prestressed frames compared to reinforced concrete frames and the base shear at yield strength for this type of frames are considerably lower than the similar value for reinforced concrete frames.

The nonlinear pushover analysis was used to evaluate an existing 8-storey reinforced concrete framed hospital building under seismic force and presented in this manuscript. The ‘Guru Teg Bahadur Hospital' is one of the important hospitals at Delhi-India, it was selected for this research. The three-dimensional frame model was used to model the building with a fixed base. The beams and columns were modeled by using three-dimension line frame elements with the centre lines joined at nodes. Diagonal strut elements were used to model the brick masonry infills. The slabs were considered as rigid diaphragms. The plastic hinge rotation capacities as per Federal Emergency Management Agency 356 (FEMA 356) with Performance Levels were adopted in this study, considering the axial force-moment and shear force-moment interactions. The nonlinear pushover analysis of the selected building was done with infills and it was observed that the infills (due to their small number in the considered building) do not make any appreciable effect on the performance level, except their failure at an early stage. The Capacity Spectrum Method (CSM) and Displacement Coefficient Method (DCM) were used to estimate the performance point of the building. The values of various coefficients as per Federal Emergency Management Agency 440 (FEMA 440) were adopted. The DCM was observed to give slightly higher target displacements, as compared to CSM. It was observed in the nonlinear pushover analysis that the unreinforced masonry (URM) infills collapse before the performance point of the building for the Maximum Considered Earthquake (MCE). As the intervention inside the functioning hospital is extremely difficult, it was explored whether it is possible to safeguard the infills by stiffening the building by providing external buttresses. Two cases of retrofitting schemes with 1.2m wide and 3m wide buttresses in transverse direction were used and analysed. It was found that this is not a practicable approach, as the infills collapse even with 3m wide buttresses. [ABSTRACT FROM AUTHOR]

Performance-Based Plastic Design (PBPD) method has been recently developed to achieve the enhanced response of structures to earthquake. To reach this goal, several ways have been suggested. In this paper, the schemes of calculating base shear in the (PBPD) procedure will be studied. Two techniques of determining base shear will be used. The base shear of two steel moment frames will be found by these two processes. By using the difference between the input energy and the elastic strain energy to obtain the plastic energy, the plastic design is then performed to detail the frame members in order to achieve the intended yield mechanism and behavior. The inelastic seismic behaviors of the four frames were studied through nonlinear static and dynamic analyses. These two suggested techniques and their comparisons have not been proposed yet. This kind of plastic design has three main parts. Calculating base shear is the first and important portion. The second part consists of the member plastic design for flexible behavior. To design elastic members by using column trees is the third and last part. Throughout this study is devoted to present two methods for calculating base shear. The moment frames will be investigated in this article.

The aim of this paper is based on the simple nonlinear procedure founded on the Park-Ang damage index model at different constant damage levels to evaluate the target displacement and performance point (P.P.). The mentioned procedure represents the intersection of the pushover capacity curve with the seismic hazard demand curve according to the equivalent period of vibration and damping in ADRS format. Hence, the damage-based response acceleration ratio is determined at different damage levels and periods for developing inelastic spectra from elastic ones. Then, the relation between the strength reduction factor (R-factor) and damage was extended at different damage levels and periods of vibration to predict the target displacement at the desired damage level, known as the performance point. It is worth mentioning that the cited procedure is represented for four hysteresis models, including Elastic-Perfectly-Plastic (EPP), Modified Clough (MC), moderate stiffness-strength deterioration (MSD), and severe stiffness-strength deterioration (SSD) models, to consider the theory for well-design and not well-designed systems in both steel and concrete structures. The mentioned procedure is the N2 theory development based on the damage model called the DN2 method in this investigation. Two experimental reinforced concrete bridge piers and three steel moment resisting frame structures with different periods, from low to high duration, are considered to verify the suggested procedure. Statistical results show that the target displacement and P.P. are evaluated appropriately regarding presented equations and proposed methodology compared to previous studies. [ABSTRACT FROM AUTHOR]

In this paper, a fairly effective procedure called dynamic load pattern (DLP), is proposed to account for the effects of near-fault ground motions in estimating the seismic demands of structures from pushover analyses. The seismic demands are obtained by enveloping the results of single-run conventional first-mode and single-run DLP pushover analyses. Improving the estimation of target displacement is another objective, implemented by performing response-spectrum analysis. Three special steel moment-resisting frames are considered and the seismic demands resulting from DLP are compared to those from the nonlinear time-history analysis as a benchmark solution, as well as to those predicted from modal pushover analysis. [ABSTRACT FROM AUTHOR]

Highlights • The impact of the target spectrum on the acceleration causing collapse is investigated. • The impact of the number of ground motions on structural response is investigated. • Several MDOF and SDOF models are considered in the study. • A minimum of 15 ground motions should be used for time-history analysis. • The CS offers 1.2–2.3 times larger accelerations causing collapse than the UHS. Abstract The impact of the type of target response spectrum and the number of ground motions on the response of buildings is investigated. The parametric study involves the selection of ground motions based on the Eurocode 8 spectrum, a conditional spectrum using the official seismotectonic model of Slovenia, a uniform hazard spectrum based on the seismotectonic model of the SHARE project, and the corresponding conditional spectrum. In addition to the variation of the target response spectrum, the number of selected ground motions was varied from 7 to 60. Selected sets of ground motions were used to investigate the seismic response of eight reinforced concrete buildings with fundamental vibration periods from 0.15 s to 1.76 s. The aim of the study was to analyse the variation of target displacements obtained by a pushover-based method, i.e. the median displacement corresponding to a seismic intensity with a return period of 475 or 2475 years, and the median spectral acceleration causing collapse, which was estimated by incremental dynamic analysis. It was found that the target spectrum and the number of ground motions have a limited impact on the target displacement, especially if it corresponds to seismic intensities with a return period of 475 years. Additionally, the impact of the number of ground motions on the median spectral acceleration causing collapse is much lower than the impact of the target response spectrum. When the conditional spectrum was used as the target spectrum for ground motion selection instead of the design response spectrum prescribed by Eurocode 8, the resulting median spectral acceleration causing collapse increased by a factor of between 1.2 and 2.3. [ABSTRACT FROM AUTHOR]

Highlights • New lateral load patterns proposed for pushover analysis of base-isolated frames. • Evaluation of lateral load patterns at three different target displacements. • The evaluation is performance for both near and far field earthquakes. • Proposed load pattern best predicts base shear, story and isolator displacements. Abstract The effectiveness of two proposed lateral load patterns (LLPs) to estimate the seismic demands of base-isolated building frames by the pushover analysis (POA) is assessed by comparing their estimates with the benchmark responses obtained by the nonlinear time history analysis (NTHA). The proposed LLPs include: (i) pattern derived from the square root of the sum of squares (SRSS) of first three mode shapes of BI frame; and (ii) two variants derived by the modification of the uniform force distribution load pattern. The conventional first mode shape LLP is also used in the POA for the purpose of comparison. A mid-rise (5-storey) and a high-rise (10-storey) base isolated (BI) reinforced concrete building frames are considered as illustrative examples for the analysis. An ensemble of five ground motion time-histories, each of far-field and near-field with forward directivity and fling-step effects are employed for NTHA. Target displacement-based comparison is performed by considering three target displacements, which cater to elastic, elastic to plastic and plastic states on the capacity curve of the building frames. The seismic demands namely, peak storey displacement, maximum inter-storey drift, number of plastic hinges, SRSS of plastic hinge rotations, maximum base shear and maximum isolator displacement are considered for comparison. The study reveals that (i) the errors in estimating the seismic demands by different LLPs depend on the state (elastic or elastic–plastic or plastic) of the building frame in which target displacement is considered; and (ii) the proposed LLP (modified uniform distribution) is found to best estimate the NTHA predictions. [ABSTRACT FROM AUTHOR]

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Recently, there have been many studies about ductility reduction factor of CBFs, because AISC's seismic design provision has been changed significantly since 2010. Therefore, a comprehensive study is needed for seismic designing and ductility reduction factor of CBFs. In this study, about 160 two-dimensional CBFs with different types of bracing are designed according to AISC-341, and ductility reduction factor of designed frames is compared to types and formation of bracings in the height of frames. The results confirm that ductility reduction factor and response modification factor of CBFs are mostly dependent on types and formation of bracing. Also, maximum allowable height of OCBFs can be reduced for some types of bracing and be increased for some other types of bracings. For SCBFs, ductility reduction factor depends on the bracing type and number of frame stories. For most of SCBFs, ductility reduction factor cannot achieve more than ten-story frames. So, for these kinds of frames, maximum allowable height should be decreased, or smaller response modification factor should be used. For double large-scale CBFs, because of the enormous stiffness of one-to-seven-story frames, ductility reduction factor cannot be obtained and a smaller response modification factor should be used. [ABSTRACT FROM AUTHOR]

This paper presents an integrated system for advanced structural analysis and seismic performance evaluation of 2D reinforced concrete frameworks. The advanced non-linear inelastic static analysis employed herein uses the accuracy of the fibre elements approach for large deflection inelastic frame analysis and address its efficiency and modelling shortcomings both to element level, through the use of only one element to model each physical member of the frame, and to cross-sectional level through the use of path integral approach for numerical integration of the cross-sectional nonlinear characteristics. Evaluation of the seismic performance is achieved with an approach that uses nonlinear time-history analysis (NTHA) of a single degree-of-freedom (SDOF) oscillator. The inelastic ductility and displacement demand is determined directly from accelerograms, without graphical or numerical approximations. Several computational examples are given to validate the effectiveness of the proposed method, the reliability and time saving of the code. The influence of the accuracy of the second-order nonlinear inelastic analysis methods involved in the modelling of the selected RC frame in conjunction with the distributions of the pushover lateral loads is pointed out. The proposed procedure is developed in the framework of Eurocode 8 design methodology, as reliable tool ready to be implemented into everyday design practice for advanced analysis, pushover analysis, and seismic performance evaluation of RC frame structures. [ABSTRACT FROM AUTHOR]