Response Spectrum Analysis Research Articles

Improved response spectrum analysis procedure for an adaptive variable friction pendulum isolated structure considering frictional dependency

The effectiveness of the conventional friction pendulum isolator (FPI) is limited in complex geographical environments and unpredictable earthquake events due to its complex frictional properties and the requirement for a unified setup target. With a view to addressing the aforementioned issues, in conjunction with an adaptive variable friction pendulum isolator (AVFPI), a simple and practical mechanical model is proposed. After applying the mechanical model with a friction-dependent influence model, an improved response spectrum analysis procedure (IRS) is proposed for variable friction pendulum isolation systems. Notably, the proposed procedure allows for the consideration of the effects of variations in velocity, temperature, and pressure on the friction characteristics without the necessity for nonlinear response history analysis (NRHA). The procedure commences with obtaining a numerical model of friction dependency through friction material examinations, then proceeds to verifying the reliability of both the friction dependency and mechanical model through prototype tests of AVFPIs. The following study presents a proposed correction method that depends on random vibration theory to establish a functional relationship between the pseudo-velocity spectrum and the velocity spectrum. Additionally, an association is established between the peak velocity and the generation of frictional heat. Finally, the procedure is evaluated based on the results of an NRHA that takes friction dependence into account through a numerically variable friction pendulum isolation system. The results of the study indicate that the IRS provides a more accurate and secure assessment of the isolator displacement at various temperatures than the response spectrum method, which does not account for the influence of frictional dependency. The failure to consider the influence of friction dependency in high-temperature environments produces an underestimation of isolator slip displacement and a subsequent increase in failure rates. The Polytetrafluoroethylene (PTFE) friction materials that are currently in widespread use exhibit a strong correlation with friction dependence and, as a consequence, cause relatively large displacements at temperatures that are both low and high. The results of this study present an opportunity to expand how response spectrum analysis techniques can be applied to friction pendulum isolation systems.

Tarihi Erzincan Çadırcı Hamamı'nın Deprem Davranışının İncelenmesi ve Günümüze Kadar Ulaşmasının Sebepleri

In this study, the earthquake behaviour of the historical Çadırcı Bathhouse in Erzincan, which is located on the North Anatolian Fault, the most active fault line of Turkey, was investigated. This historical masonry structure has preserved its structural integrity despite being exposed to two earthquakes of magnitude 7.8 in 1939 and 6.7 in 1992. In accordance with the architectural survey studies, the historical building was modelled in 3D in two different types according to shell and solid modelling techniques. According to the results of response spectrum analysis, stress and displacement distributions and modal characteristic parameters of the structure were evaluated. When the analysis results of the models created with the solid model technique and the shell model technique are compared, it is concluded that the shell modelling technique is safe in such studies, considering the analysis time and modelling difficulty. According to the results of the analyses, considering the stress distribution in the historical building elements, it is seen that the configuration characteristics of historical masonry structures are important in earthquake resistance like other building systems.

Comparison of Linear and Nonlinear Procedures for the Analysis of the Seismic Performance of Straight Multi-Span RC Bridges

The assessment of the seismic performance of transportation infrastructures is of primary importance for the management of the aftermath of an earthquake. To perform such an assessment, various modeling approaches characterized by different levels of accuracy are available and modern seismic design codes provide recommendations about their use. Non-linear time-history analysis (NLTHA) is acknowledged as the most reliable method, but is difficult to implement and is computationally expensive. This paper aims to investigate the viability of less complex methods, but with low computational cost, for the assessment of straight, multi-span bridges and compare their performance against the results of NLTHA in order to quantify the expected accuracy. The study is developed considering three bridge archetypes with either simply-supported or continuous-deck layouts, representative of typical features of the Italian bridge stock. The bridges are analyzed first through nonlinear dynamic analyses, to define the benchmark solution; then linear dynamic analyses, such as Linear Time-History and Response Spectrum Analysis, nonlinear static analyses, such as MPA (Modal Pushover Analysis), and Equivalent Static Analysis are considered. A comparison among the examined procedures is eventually proposed, highlighting the strengths and weaknesses of each approach.

Research on vibration response of 550 kV GIL isolation compensation unit against earthquake loading

To analyze the vibration response of Gas Insulated Transmission Lines (GIL) of urban power grid under different seismic intensity levels, based on the actual structure of the standard isolation compensation unit (isolation unit and compensation unit) of 550kV GIL, A fine 3D model of isolation compensation unit segment of 550 kV GIL was established, and the actual vibration response of each standard unit segment of GIL under different seismic conditions was studied by response spectrum analysis. This study clarified the action mechanism and law of GIL vibration characteristics under seismic conditions of urban power grids, provided the relative support for the research of shock absorption of GIL, and was great significance to the actual project of GIL.

Response Characteristics of Irregular Continuous Rigid Frame Bridges with Long-Span and High-Rise Piers under Ground Motion Excitations with Different Fault Distances

An innovative seismic performance evaluation strategy for irregular rigid frame bridges with a long-span and high-rise piers under the action of ground motions with different fault distances is presented in this paper. A total of 129 mainshock records taken during the Wenchuan earthquake, from national seismic stations with different fault distances, were analyzed using statistical methods, to determine the attenuation characteristics of the intensity index of the Wenchuan earthquake records from the perspective of aseismic engineering, and the attenuation of the acceleration response spectrum is discussed. The Miaoziping Bridge on the Dujiangyan–Wenchuan Expressway, which was damaged in the Wenchuan earthquake, is taken as the analysis background; two sets of samples for long-span continuous rigid frame bridges with different pier heights are constructed, to discuss the seismic response characteristics of continuous long-span rigid frame bridges; and representative values for the natural periods of these two bridge structural groups are subsequently compared and analyzed. After the peak responses for various bridges with various pier heights are determined through a response spectrum analysis under the action of ground motions with different fault distances, and the surfaces for the obtained peak responses are fitted and the response characteristics for different fault distances are discussed. It is shown in the results that the seismic response characteristics of the continuous rigid frame bridges with long-span and high-rise piers were significantly different under the action of the ground motions with different fault distances, and the seismic responses of these two bridge groups were distinctly larger under the action of near-fault ground motions. Furthermore, based on the above research, suggestions for the pier arrangement and bridge site selection for continuous rigid frame bridges with long-span and high-rise piers are also discussed. The results of this paper also provide some theoretical guidance for the sustainable development of bridges with long-span and high-rise piers, from the perspective of bridge seismic response characteristics.

Deep learning‐based response spectrum analysis method for building structures

AbstractThe response spectrum method has gained widespread acceptance in practical applications owing to its favorable compromise between accuracy and practical efficiency. The method predicts the peak responses of multi‐degree‐of‐freedom (MDOF) systems by combining modal responses. The Square Root of the Sum of Squares (SRSS) and Complete Quadratic Combination (CQC) rules are commonly used for modal combinations. However, it has been widely known that these rules have limitations in accurately predicting responses influenced by higher modes and cross‐modal correlations. To improve the accuracy of the response spectrum analysis method for building structures, this paper proposes a Deep learning‐based modal Combination (DC) rule by introducing modal contribution coefficients predicted by a deep neural network (DNN) model. The DC rule enhances prediction accuracy by considering the characteristics of ground motion and the dynamic properties of a structural system. The DC rule provides more accurate predictions than the conventional rules, particularly for irregular response spectra and responses affected by higher modes. The efficiency and applicability of the DC rule are demonstrated by numerical investigations of multistory shear buildings and steel frame structures with regular and irregular shapes. The source codes, data, and trained models are available for download at https://github.com/tyongkim/ERD2.

Response Spectrum Analysis of Adding External Elevators to Existing RC Buildings

In contemporary society, elevators stand as indispensable facilitators, particularly for users in tall buildings, contributing significantly to convenience. Their role becomes even more crucial for individuals with disabilities, serving as a vital means of transport to enable them to partake in modern life. However, a challenge emerges in the form of buildings erected during the 1970s or 1980s, lacking initial designs of elevators. This absence of elevator well designs presents substantial issues for building users, especially residents. However, many of these buildings have not reached the end of their service life. Undertaking removal and reconstruction efforts, while a potential solution, raises serious environmental concerns. The associated carbon dioxide emissions and the environmental impact of such activities underscore the need for alternative, environmentally conscious approaches. In this context, the introduction of external elevator structures to existing buildings emerges as a meaningful and sustainable avenue for researchers to explore. The proposed solution not only addresses the practical challenges faced by residents but also aligns with broader environmental goals, contributing to the reduction of carbon emissions and the preservation of existing building structures. Many researchers emphasize the critical importance of assessing structural performance under seismic loads to ensure safety. This research, centered on a typical educational RC frame structure at Kyungpook National University, employs the RSA (Response Spectrum Analysis) method to comprehensively evaluate seismic performance. This research specifically compares analytical results using RSA for the RC frame with and without the external elevator structure (RCE and RC, respectively).

Implications of the 2020 National Building Code of Canada updates on the design demands for reinforced concrete shear wall buildings

The seismic demands of the Reinforced Concrete Shear Walls (RCSWs) system are determined based on Canada’s National Building Code (NBC). NBC 2020 features the revised Canadian Seismic Hazard Model and presents the possibility of enhancing demand’s accuracy by determining design spectra based on the specific average shear wave velocity, instead of specified site classes. This paper investigates the changes in design demands for RCSWs compared to the previous edition. To do so, fifty-five RCSW prototypes were modelled using distributed mass and stiffness procedure, and their dynamic response was assessed through Modal Response Spectrum Analysis at five locations across Canada. The results highlight significant changes in deformation and force demands, where the majority of cases experienced an increase in 2020 compared to 2015 when demands were determined based on specified site classes. This study also evaluates the log-log interpolation method recommended by NBC 2020 for the design spectral acceleration.

Dynamic-Based Limit Analysis for Seismic Assessment of Free-Standing Walls of San Giovanni Church in Castelseprio UNESCO World Heritage Site

Free-standing archaeological walls are significantly exposed to horizontal actions (e.g., earthquakes) as they lack connections provided by floors or roofs. In such cases, the dynamic response governs the activation of local mechanisms of collapse, determining the shape of the macroblocks and their position. Engineering models of archaeological walls are developed according to the results of extensive visual inspections and on-site testing, including modal identification for calibration purposes. A modal response spectrum analysis on the calibrated model identifies the zones where the tensile stress is exceeded, which are more likely to detach as rigid macroblocks and subsequently overturn due to the expected ground spectra. The macroblocks are then assessed according to limit analysis. The case studies are the north and the apse walls of the church of San Giovanni Evangelista in Castelseprio (Varese, Lombardy), a 5th century Longobard fortified settlement, a part of UNESCO World Heritage. The construction quality of the apse was poorer than the north wall, but the masonry of both is very compact thanks to the good mortar. The macroblocks are identified mostly in the upper crests of the walls, and their acceleration of activation is two to six times larger than the demand (considering the dynamic amplification that the structure applies to the ground motion); therefore, no particular intervention is needed. The proposed method will require additional calibration, e.g., through nonlinear dynamic analyses, and a more precise treatment of uncertainties in masonry mechanical properties to determine the shape of the macroblocks.

SEISMIC BEHAVIOR OF MULTI-STORIED RC BUILDING WITH RE-ENTRANT CORNER

Nowadays, buildings often feature irregular floor plans for functional, aesthetic, or economic reasons. Constructing earthquake-resistant structures in seismic areas, especially with irregular shapes like re-entrant corners, poses challenges. Such corners are common when maximizing limited space is a priority. In earthquakes, re-entrant corners in structures pose major vulnerabilities, causing stress concentration and torsion problems. The main aim of this paper is to develop finite element structural analysis models of 10, 12, and 15-storied L-shaped RC buildings with a re-entrant corner under different seismic zones using equivalent static analysis (ESA) and response spectrum analysis (RSA). This research also focuses on the overall behavior of analysis results (story drift, overturning moment, base shear, etc.) with the influence of re-entrant corner. It also investigates the performance of columns and beams near re-entrant corners as the number of stories increases in different seismic zones. For the current study, ETABS V19 is used. Models consider seismic, dead, and live loads. The Bangladesh National Building Code (BNBC) 2020 is used to examine the equivalent static analysis (ESA) and the response spectrum analysis (RSA) methods. It has been concluded from the study that re-entrant corner beams consistently exhibit the highest bending moments and torsion levels across all seismic zones. Similarly, re-entrant corner columns consistently demand the most axial force and rebar when compared to similar column types. Furthermore, the study identifies maximum stress levels in re-entrant corner slabs across all seismic zones.

A diagram‐based design procedure for Intermediate Isolation System in existing buildings with inelastic behavior

AbstractVertical extensions of existing buildings can be realized through Intermediate Isolation System (IIS): the extension, equipped with a base isolation system on the rooftop of the existing building, can work as a mass damper, thus reducing the seismic demand on the old structure. The idea proposed in this paper is to predict the elastic or inelastic response of the existing structure in the IIS configuration by means of the results of simple linear analyses. Parametric response spectrum analyses are performed on simplified two degree‐of‐freedom models by varying the mass ratio and the periods of both the existing building and the new isolated vertical extension. So‐called IIS design spectra are derived, and the results are provided as design charts. Given the period of the existing building and the mass ratio, the period of the new isolated vertical extension is selected to obtain the required/desired response of the existing building. For existing buildings working in the elastic field, the designer can derive the response of the existing building by utilizing the IIS design spectra as design charts. For existing building working in the inelastic field, the design charts can still be adopted, though within a more complex procedure, which accounts for two limit behaviors that the extended building exhibits in the inelastic field. The outlined design procedure is applied to some case studies and validated through the comparison with the results of nonlinear time history analyses.

Investigating Three-Dimensional RCC Frames under Seismic Loading with Various Soil Conditions

Equivalent lateral forces are used in earthquake engineering to build structures that can survive seismic shocks. Considering seismic waves affect how the Earth moves, buildings in India’s seismically active areas must be built to withstand earthquakes. This study examines how multistorey reinforced concrete building frames function seismically while taking into account different soil types, loading scenarios, and seismic Zones IV. For a twelve-storey skyscraper, the analysis includes earthquake reaction storey displacement. This study looks into how soil changes in seismic zone IV affect buildings’ responses, as well as how seismic zones themselves affect them. The building’s natural time periods were evaluated using both response spectrum analysis and time history analysis methods. These results provide insightful information about the complex interaction between soil type and seismic zone, Member stresses and maximum displacement are calculated using static and dynamic analysis. In India’s seismically active region, the necessity for earthquake-resistant structures is highlighted by seismic waves that alter the motion of the earth. Response spectrum analysis combines modal responses via techniques including SRSS, CQC, and ABS, taking into account a variety of response modes. This study compares earthquake loads using various soil types in Zone IV to evaluate building performance during earthquakes. This project’s primary goal is to analyse a multistorey building’s seismic response. Staad Pro Software does load calculations in order to analyse the entire structure. Staad-Pro analysis employs the Limit State create approach, which complies with the Indian Standard Code of Practice.

Analysis of the Structure of the Existing Mess Korem 012 Building as an Alternative Safety Building in Meulaboh

West Aceh district is one of the districts that was affected by the earthquake and tsunami that occurred in 2004. As a district that is in a strong earthquake condition, the aspect of earthquake-resistant buildings is an important object of concern. The Mess Ex KOREM 012 building is one of the buildings that was affected by the 2004 earthquake and tsunami tragedy, resulting in damage to structural elements. There are still very few alternative rescue buildings in Meulaboh, so the former Korem 012 Mess Building is an alternative that can be used to build this building. So this study aims to determine the structural capacity of the Mess Existing Korem 012 building which is intended as an alternative rescue building. This research method uses response spectrum analysis using the Structural Analysis Program (SAP2000) to obtain a structural response to the internal forces of the structure. These data were then processed again with SNI 2847-2019 in order to obtain data on the interaction of forces and moments of the P-MM column ratio and the joint ratio of beam-column relations (HBK). To produce data on the ability of structural elements in accordance with the Requirements for Special Moment-Bearing Frame Systems (SRPMK). The results of the analysis show that in the column area, there is a P-MM condition and the joint ratio HBK > 1. This shows that the ratio of structural capabilities exceeds the capability of the structure, thus the structure of the Mess Ex Korem 012 Building must be repaired to meet the earthquakeresistant building requirements of the SRPMK so it deserves to be used as an alternative rescue building in Meulaboh.

Earthquake Measurements and Those Analysis on IR Components and Belle II Detector in KEK

Earthquakes frequently occur in Japan. Even though countermeasures are thoroughly considered and well executed, earthquakes still impact facilities and experimental devices. The large relative displacements induced by an earthquake can damage beam pipe bellows and interfere with sub-detectors by causing the tolerance between them to disappear. Even magnet quenches have been triggered by induced voltages caused by the relative displacements between the superconducting solenoids (i.e., the detector solenoid and the compensating solenoids surrounding the final focus quadrupole magnets, or QCSs). In response, we installed acceleration sensors on the Belle II detector and mounted gap sensors on the QCSs to measure the relative displacements. These measurements enabled the characteristics of the earthquakes that have affected the Belle II detector to be analysed. Response spectrum analyses (RSAs) of the Belle II detector were conducted to evaluate the impact of earthquakes according to the ground motion measurements. We then compared the measurements to the RSA results, which led to an idea for a countermeasure.

Study on Seismic Performance of Reinforced Concrete High-Rise Building with Buckling Restrained Braces Dissipation Devices

Performance-based Seismic Engineering is the modem approach to Earthquake Resistant Design to control lateral deflection and inter-story drifts. It is a significant challenge to overcome in the execution of high-rise buildings. Since structures are subjected to lateral loads, the Utilization of dissipation devices such as the bracing, shear wall, and dampers are a possible method to enhance the structural performance of the high-rise building under load cases. These cases are varying to static and dynamic ones as Response Spectrum. Properly designed and detailed structures with dissipation devices have exhibited excellent performance during a severe earthquake. Lateral forces due to will be resisted in its plane. In continuation studies of reinforced concrete structure compared to the absorbing devices, Three essential reinforced concrete buildings were taken for analysis G+ 30 floors to cover the broader spectrum of high-rise building construction. Software ETABS carried out seismic analysis through Response Spectrum Analysis. The result highlights how structural damper systems perform much better than other systems with accuracy and exactness through the parameters of Displacement, Drift, Base shear, and Stiffness. Damper structures are more suitable for high-rise buildings and earthquake zones due to this study's results; maximum height of systems could be possible, which must be economically less expensive than steel structure of the same height.

Optimizing the Integration of Building Information Modelling using Response Spectrum and Linear Time History Analysis. Case Study: Irregular Hangar Structure

The increasing use of technology in the construction industry has introduced the concept of Building Information Modeling (BIM), which is widely utilized to streamline construction activities. BIM enables the exchange of data across various disciplines quickly, as well as facilitates analysis, design, and on-site construction processes. The implementation of BIM will be carried out in the analysis and design processes of structures with irregularities to assess the effectiveness and performance of BIM in modeling and analyzing structures. Considering the burgeoning development of the construction industry in Indonesia, there is a necessity for a laboratory hangar dedicated to conducting structural model tests and construction material examinations. The aim of this study is to compare the response and the volume output between the response spectrum and linear time history analysis of an irregular structure. The case study conducted in this research focuses on the 5-stories Laboratory Hangar in Indonesia. The software used in this study includes Autodesk Revit 2023 for BIM modeling and ETABS V21 for structural analysis. Data and model exchange are performed between both software platforms to evaluate the BIM integration between them.

Comparative Study Probabilistic Seismic Risk Assessment for Regular and Irregular RCC Buildings

In the study numerous buildings exhibit irregularities of their architectural plans, a feature that could render them susceptible to excessive seismic activities in the future. The purpose of this paper is to evaluate the seismic vulnerability and response of regular and irregular shaped multi-storey building of identical weight in context. Both static and dynamic (response spectrum) analysis has been done to observe the influence of shape of a building on its responses to various loading. G+12 storied regular (rectangular) and irregular shaped buildings have been modeled using program staad pro for seismic zone III. Impact of wind and static load on exclusive formed shape along with dynamic response spectrum has been meticulously analyzed considering the mass of each shaped is identical. A comparative analysis of the center of mass and maximum displacement overstorey of variously shaped buildings under static loading and dynamic response spectrum has been conducted. All form buildings react nearly in sync if the total mass fluctuates only little. But as the end result indicates, a structure's irregular dimensions are what expose it to its vulnerable direction. It is possible to build an irregularly shaped structure that might act more like a rectangular building while keeping the total mass the same.

Parametric Study of Three Dimension RCC Frame Structure for During Earthquake Condition

In India’s seismically active region, the necessity for earthquake-resistant structures is highlighted by seismic waves that alter the motion of the earth. Response spectrum analysis combines modal responses via techniques including CQC, and ABS, taking into account a variety of response modes. This study compares earthquake loads using various soil types in Zone III and evaluates building performance during seismic events. The primary goal of the entire project is to analyse the seismic response of multistory buildings. Staad Pro Software does load calculations in order to analyse the entire structure. The outcomes turned out to be incredibly exact and precise. A G+7 and G+10 storey building was examined for every potential load combination (seismic, live, and dead loads) during my analysis and design process. The highly interactive and user-friendly user interface of Staad. Pro allows. Numerous factors that may impact earthquake ground movements and associated reaction spectra are included in analytical approaches for site response analysis. To ensure that assessments of earthquake ground motons at the site are reliable, it is crucial to look into how these parameters affect site reaction analysis. The parametric study presented in this work looks into how site factors affect ground motion during earthquakes. We calculated the response reduction of the common moment-resisting body case and the unique moment-resisting frame values Tall Construction’s seismic reaction using the Staad Pro programme.

The choice of the control displacement in pushover analysis of bridges: a case study

Seismic assessment of existing bridges requires consideration of the structural inelastic behaviour. Non-linear static methods (i.e., pushover) have become a standard tool in civil engineering practice for the analysis of various structural typologies, including bridges, due to simplicity compared to non-linear dynamic analysis. Nevertheless, the extensions of the applicability of pushover methods to bridges seem to show peculiar relevant questions. This work presents a case study of non-linear static analyses of an existing reinforced concrete (RC) highway beam bridge. Among the numerous proposals available, traditional pushover analysis has been chosen as the analysis method. The simply supported beams bridge has a total length of around 706 m, with 16 spans of 43 m each; the simple deck is made of reinforced concrete beams pinned over the multiple stem piers, whose height varies regularly from 11 m to 5.5 m. Non-linear behaviour of bearing devices, soil-abutment interaction system and expansion joints (closure) have been accounted for. The analysis has been performed in both longitudinal and transverse directions, subjecting the structure to the following load distributions: (i) constant along the deck and (ii) one that considers the contribution of the modes according to the response spectrum analysis. The case study seems to confirm the importance of the reference point selection in the bridge seismic assessment via pushover method. The pushover has been compared with the results of dynamic non-linear analysis.

Seismic retrofitting of an existing hospital with external steel brace

Earthquakes may cause serious damage to buildings and result in heavy losses to society, therefore, it is necessary to enhance the seismic capacity of existing buildings via structural retrofitting. The traditional retrofitting approaches are based on the component-level, but their improvement effect for the overall structure is not obvious. Until now, the seismic retrofitting technology can be generally divided into three types. The first is strength-improving type, the second is ductility-improving type, and the third is seismic dissipation/isolation type. Commonly a combination of these three types is used in retrofitting solutions. Most of them are focused on member based or component-level improvements of strength and/or ductility applied to poorly reinforced concrete walls or columns and masonry walls. Meanwhile, the weak element of the existing structure can be strengthened by external sub-structures as steel frames to make the overall structural capacity or stiffness more uniform. In addition, because the construction is an external operation, it can achieve non-disturbing retrofitting without affecting the normal use of the inner structure, which is of great practical significance and social benefits for lifeline projects such as schools and hospitals that cannot be interrupted. In the present case study, the efficiency of a seismic retrofitting with external steel frame of the university hospital Zurich (USZ) will be discussed. The original 3-story reinforced concrete building with a rectangular floor plan of 44m x 24m was built in 1966. Subsequently, in 1970, the building was extended by 4 floors with a composite steel structure. On the roof floor there is a helipad for emergencies. The stiffening steel structure was connected to the building with post-installed anchors. The first results of a response spectrum analysis showed major deficiencies in terms of horizontal and torsional stiffness, so that a strengthening measure became necessary. The results were verified by means of a push-over analysis, which showed that the measure applied was very effective. Finally, the structural design and the connection details to the existing concrete structure are shown.