Earthquake-resistant Structures Research Articles

Seismic response of combined piled raft foundation using advanced liquefaction model

The design of earthquake resistant structures founded on combined piled raft foundation (CPRF) mainly depends on raft-pile-soil interaction (RPSI). This interaction become more complex for these heavy structures, if founded on the liquefiable soil. The CPRF is considered to be useful foundation in practice to support such heavy structure; in which both raft and pile increase the bearing capacity of the soil. Where raft reduces the liquefaction induced settlement and piles help to transfer the load of the structure to the non-liquefiable soil layer. The aim of this paper is to carry out the 3D nonlinear finite difference analysis of CPRF considering the RPSI. A recently developed constitutive model i.e. CycLiq for the liquefaction modelling of the soil is utilized to represent the behaviour of sand in inelastic range which consider the cyclic behaviour and large post-liquefaction shear deformation of sand. The validation of the model is carried out with the centrifuge data. The effect of CPRF over the raft and pile group is carried out for harmonic excitation with varying frequency and earthquake motion with varying PGA. The study provides important observations and insights that were not previously evident. The findings emphasize the need to consider frequency effects, geometrical nonlinearity, and material nonlinearity in the design of NPP structures. Additionally, the study introduces the application of the CycLiq liquefaction model and the development of a user-defined material for FLAC3D. Further, the outcome shows the useful conclusion on the importance of CPRF foundation over the conventional foundation i.e. raft and pile group in the liquefiable soil. It is found that excitation frequency, ground motion PGA, porosity of sand and pile spacing of CPRF have great effects on the response.

Analysis of Base Shear and Story Drift in the Low-Rise RC Sructure

<p class="Abstract">Earthquakes frequently occur in Indonesia because it is an earthquake-prone area. Due to lateral load from an earthquake can cause a weakly constructed building to collapse. Designers often only consider tall buildings in designing earthquake-resistant building structures but ignore earthquake-resistant designing for low-rise buildings. This study focuses on the analysis of earthquake resistant structures with a case study of low-rise buildings in the form of a 3-story reinforced concrete (RC) building in the South Jakarta area. The objective of the study is to analyze the base shear and story drift of the structure due to lateral or earthquake loads. The structure is a reinforced concrete with the concrete compressive strength of <em> </em>= 30 MPa and longitudinal reinforcement of = 420 MPa and stirrups of = 280 MPa. This study uses equivalent static analysis manually and using ETABS 20.1.0 application. The results showed that three story buildings analyzed using equivalent static analysis method and using ETABS 20.1.0 application had almost the same results on horizontal forces with manual result of 1680.97 kN and ETABS of 1648.46 kN. The elastic story deflection and inelastic story drift in this study are still within safe limits because it is below the drift limit.</p>

A study of the relevance of seismic steel structures to urban carbon neutrality

Global warming has triggered dramatic climate change and natural disasters. Since the 21st century, the frequency of all kinds of extreme weather has increased significantly. This study, in accordance with the carbon peak targets and stage requirements, improve the building low carbon building standards system, accelerate the formulation, revision and collation of energy-saving design standards for public buildings energy-saving and carbon reduction standards. The application of earthquake-resistant steel structure of the building, the promotion of green low carbon building materials and green construction methods. Actively promote such buildings, the past sixty years each country's carbon emissions intensity have shown a general downward trend, especially South Korea, South Africa and Brazil and other countries due to economic development began to focus attention on environmental issues. In this study, we take Busan, Korea as an example, and use carbon neutral calculations to realize carbon neutrality by designing superstructures with a reduced degree of intensity, so that the reduction of carbon emissions mainly includes emission reductions brought about by a reduction in the amount of steel and cement used. It is hoped that this study will be taken into account, and that the early realization of peak carbon emissions in South Korea will be the current situation to be realized, and will be a challenge not only for developing countries, but also an important issue to be considered by all countries.

Methods of Assessing the Damage Capacity of Input Seismic Motions for Underground Structures

This paper investigates a method for improving the selection of seismic motions for designing earthquake-resistant underground structures. It is found that PGV alone is unreliable as a predictor of structural damage with increasing earthquake intensity. Therefore, based on characterizing seismic intensity by using PGV, another parameter, referred to here as “the severest parameter”, is introduced to distinguish potential damage capacity for different seismic motions. A numerical model of a soil–underground structure system was established using the finite element software OpenSees. A total of 120 real ground motions were selected for the model, considering the influences of eight different site groups on the underground station and the rupture distances of the input seismic motions. The results show that as seismic intensity increases, substantial variability in the response of underground structures emerges under the same amplitude of PGV, diminishing the effectiveness of the relationship between PGV and structural damage. When assessing the potential damage capacity of seismic motions with similar or close amplitudes of PGV, VSI is an appropriate severest parameter for Class III sites and ASI is suitable for Class II sites. When the correlation coefficient between the severest parameter and the structural response is greater than 0.8, it can be used to reliably assess seismic damage capacity based on the size of the severest parameter.

Experimental investigation on the effect of hoop spacing and crosstie configuration on the cyclic performance of reinforced concrete beams

According to ACI 318-19(SI), in the plastic hinge zone of RC beams, the longitudinal reinforcement at each corner and every other longitudinal reinforcement must be enclosed by the corner of the closed hoop or the hooks of crossties. However, in RC construction practice, the longitudinal reinforcement of RC beams is densely arranged, making construction difficult. In this study, four large RC beam specimens were designed and fabricated to conduct experiments to verify the effect of hoop spacing and crosstie configuration on the cyclic performance of reinforced concrete beams. It is found that: (1) The crosstie configuration with seismic hook engaging the longitudinal reinforcement at the bottom is recommended and that during construction, within the range of twice the beam depth from the RC column outer face, the bottom and side formwork should be completed after the crossties are assembled, which should solve the problem of difficult construction. (2) The transverse reinforcement spacing between 4 and 6 times the smallest longitudinal reinforcement diameter of RC beams may have no significant effect on the cyclic performance of RC beams. (3) The requirement that in the plastic hinge zone of RC beams, every corner and alternate longitudinal bar on the perimeter must have lateral support provided by the corner of a tie or crosstie in ACI 318-19(SI) may not have a major impact on the cyclic performance of the RC beam. (4) The ultimate drift angle of each specimen in the negative direction was between 4.3% rad and 4.5% rad; thus, all the specimens satisfied the ACI requirement. However, the cyclic performance (plasticity rotation angle) of all specimens basically did not meet the requirement of 3.0% rad for earthquake-resistant structures.

WITHDRAWAL – Administrative Duplicate Publication: Seismic Architecture: The Architecture of Earthquake Resistant Structures

WITHDRAWAL – Administrative Duplicate Publication: Seismic Architecture: The Architecture of Earthquake Resistant Structures

WITHDRAWAL – Administrative Duplicate Publication: Seismic Architecture: The Architecture of Earthquake Resistant Structures

WITHDRAWAL – Administrative Duplicate Publication: Seismic Architecture: The Architecture of Earthquake Resistant Structures

Multi-objective optimization of energy-dissipating steel plate fuse links using response surface method

Steel plates with openings are used to provide energy dissipation in earthquake-resistant structures. Shear-acting steel plates with butterfly-shaped or straight links are particularly used as easily replaceable fuses in low-damage design of structures. Sensitivity analyses have shown that the cyclic response of steel plate fuses varies depending on the shape of the fuse link. However, simultaneous response optimization approaches have not been applied in the past research on steel plate fuses. A multiple-response optimization study is needed to find optimal link shapes with improved cyclic response characteristics while simultaneously considering different optimization objectives. In this study, experimentally validated finite element simulations and response surface methodology are used to predict the cyclic load-displacement response of steel plate fuses. The behavior of steel plate shear links is evaluated in terms of initial stiffness, yield strength, ultimate stiffness, effective damping, peak strength, and ductility. Predictive equations are derived and verified for each response characteristic in terms of three influential factors, including the length to end-width ratio (L/b), end-width to thickness ratio (b/t), and mid-width to end-width ratio (a/b) of shear links. The predictive equations are then employed to perform multi-objective optimization studies using a desirability approach. Four different optimization objectives are considered, such as the maximization of effective damping and ductility. Optimal ranges are determined for each factor. The results show that the energy dissipation, strength, and ductility of the fuse can be simultaneously maximized if using relatively thick and moderately long links (with b/t smaller than 6.6, L/b between 2.7 and 6, and a/b between 0.33 and 0.96). Optimal fuses links are those with an intermediate a/b between 0.37 and 0.89 and a small to moderate b/t between 3.0 and 6.6.

Strength and Deformability of Structural Steel for Use in Construction

The purpose of the study is an experimental determination of the stress-related characteristics of the structural steel produced in the Republic of Kazakhstan for use in conventional and earthquake-resistive construction. Since 2015, the construction industry has been using European regulatory documents—Eurocodes—as a statutory framework. In particular, the Eurocode 1993 for steel structures and the Eurocode 1998 for the design of earthquake-resistant structures However, the study of stress-related properties of structural steel using experimental methods of ISO standards has not been performed. Therefore, in the construction industry of the Republic of Kazakhstan, steel-work structures have been used in fairly limited volume since 2015. The experimental studies were conducted on 7 types of structural steel with thicknesses of 8, 10, and 20 mm manufactured by Arcelor Mittal. The yield strength, ultimate tensile strength (breaking stress), and tensile strength at break were studied. The experimental studies were carried out on the basis of ISO standards. In each test run, 5 samples were used. In two series, 20 samples each were tested, which made it possible to estimate the yield strength and strength distribution functions. The correlation relationships between Brinell hardness and yield and strength limits have been studied. As a result of experimental studies, it was found that the strength and deformability parameters fully comply with the requirements of Eurocode 1993. Based on the application of the Student's test, it is revealed that the distribution functions of yield strength and resistance correspond to the normal law (Gaussian function). The calculation of a three-story, two-span residential building with box section columns for construction in an area with a seismicity of 8 points is performed by the finite element method. The work results will significantly increase the scope of Kazakhstani structural steel use in seismic and conventional areas of the Republic of Kazakhstan. Doi: 10.28991/CEJ-2024-010-03-09 Full Text: PDF

Seismic Isolation Materials for Bored Rock Tunnels: A Parametric Analysis

Most recent tunnel designs rely on more thorough analyses of the intricate rock interactions. The three principal techniques for excavating rock tunneling are drill-and-blast for complete or partial cross-sections, TBM only for circular cross-sections with full faces, and road header for small portions. Tunnel-boring machines (TBM) are being utilized to excavate an increasing number of tunnels. Newer studies have demonstrated that subterranean structures such as tunnels produce a variety of consequences during and after ground shaking, challenging the long-held belief that they are among the most earthquake-resistant structures. Consequently, engineering assessment has become crucial for these unique structures from both the geotechnical and structural engineering standpoints. The designer should evaluate the underground structure’s safety to ensure it can sustain various applied loads, considering both seismic loads and temporary and permanent static loads. This paper investigates how adding elastic, soft material between a circular tunnel and the surrounding rock affects seismic response. To conduct the study, Midas/GTS-NX was used to model the TBM tunnel and the nearby rock using the finite element (F.E.) method to simulate the soil–tunnel interactions. A time–history analysis of the El Centro (1940) earthquake was used to calculated the stresses accumulated in the tunnels during seismic episodes. Peak ground accelerations of 0.10–0.30 g, relative to the tunnel axis, were used for excitation. The analysis utilized a time step of 0.02 s, and the duration of the seismic event was set at 10 s. Numerical models were developed to represent tunnels passing through rock, with the traditional grout pea gravel vs. isolation layer. A parametric study determined how isolation material characteristics like shear modulus, Poisson’s ratio, and unit weight affect tunnel-induced stresses. In the meantime, this paper details the effects of various seismic isolation materials, such as geofoam, foam concrete, and silicon-based isolation material, to improve protection against seismic shaking. The analysis’s findings are discussed, and how seismic isolation affects these important structures’ performance and safety requirements is explained.

Seismic design of reinforced concrete buildings equipped with viscous dampers using simplified performance-based approach

Passive control systems, such as Fluid Viscous Dampers (FVDs), have gained significant consideration in the design of earthquake-resistant structures. However, simple analysis and design methods are scarce for more practical and feasible implementation. This study provides a simplified procedure for performance-based seismic design of Reinforced Concrete (RC) special moment resisting frame using nonlinear FVDs. It adopts an extended performance-based design approach, focusing on maximum displacement along with floor acceleration to control the overall behavior of the structure. The fundamental principle of the method is to achieve the fully stressed (effect of FVDs on response indices) design approach to place dampers, which is attained by placing dampers among the storeys where drifts exceed the pre-decided performance limits. Further, a uniform damage distribution concept is followed to maximize the dampers' capacity. This study examines a rectangular-shaped RC SMRF with dampers to get the required performance when subjected to design basis and maximum considered earthquake levels. To check the efficacy, the proposed method is contrasted with a practical design method and a standard placement method employed in previous studies for RC structures with dampers. The analysis shows that the structure meets the performance targets of the design basis and the maximum considered level of earthquake hazards using the proposed step-by-step procedure. The comparison with the other two methods confirmed that the structure with dampers improved seismic behavior with the suggested process. Structural engineers can refer to the proposed method for the design of RC buildings with FVDs.

OpenSeismoMatlab: New Features, Verification and Charting Future Endeavors

To facilitate the precise design of earthquake-resistant structures, it is imperative to accurately evaluate the impact of seismic events on these constructions and predict their responses. OpenSeismoMatlab, a robust, free ground motion data processing software, plays a pivotal role in this endeavor. It empowers users to compute a wide array of outcomes using input acceleration time histories, encompassing time histories themselves, as well as linear and nonlinear spectra. These capabilities are instrumental in supporting structural design initiatives. This study provides a comprehensive exposition of the latest version (v 5.05) of OpenSeismoMatlab. It delves into intricate facets of the software, encompassing a detailed exploration of the input and output variables integral to each operational category. Comprehensive calculation flowcharts are presented to elucidate the software’s organizational structure and operational sequences. Furthermore, a meticulous verification assessment is conducted to validate OpenSeismoMatlab’s performance. This verification entails a rigorous examination of specific cases drawn from existing literature, wherein the software’s outcomes are rigorously compared against corresponding results from prior studies. The examination not only underscores the reliability of OpenSeismoMatlab but also emphasizes its ability to generate outcomes that closely align with findings documented in the established body of literature. Concluding the study, the paper outlines potential directions for future research, shedding light on avenues where further development and exploration can enhance the utility and scope of OpenSeismoMatlab in advancing seismic engineering and structural design practices.

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.

Application of Pebbles for Geotechnical Seismic Isolation (GSI): Experimental Parametric Study

Low-income regions do not have the economic strength to use conventional isolators; therefore, low-cost alternatives are needed. The recent series of earthquakes in Turkey has once again demonstrated the destructive power of this natural disaster and highlighted the need for high-quality earthquake-resistant structures. In this context, a comprehensive experimental parametric study on the use of natural stone pebbles (ASL-1) and stone pebbles in combination with a geogrid layer (ASL-2) as suitable materials for a GSI system is conducted and the main results are presented. The seismic behavior of five different models was tested using four different acceleration diagrams with different peak ground accelerations (PGAs). Characteristic displacements, accelerations, and strains were measured. The results and conclusions presented are based on the integration and synthesis of several previously conducted studies.

Reevaluating Earthquake Fatalities in the Taiwan Region: Toward More Accurate Assessments

Abstract Earthquakes occurring in the Taiwan region have the potential to cause significant damage and loss of life. To ensure an effective emergence response and mitigate the impact of seismic events, it is imperative to develop an earthquake fatality prediction model that incorporates the Taiwan region’s seismic background, geological context, and socioeconomic level. This research article analyzes 35 historically damaging earthquakes in the Taiwan region, considering their fatality records, macroseismic intensities (modified Mercalli shaking intensity scale), and population exposure, to propose a specific seismic fatality ratio applicable to the Taiwan region. The model incorporates adjustments based on the gross national income per capita to address temporal and spatial disparities resulting from socioeconomic development. The predicted results highlight the superior performance of this fatality estimation model compared to other existing models. Furthermore, the earthquake fatality estimation model for the Taiwan region differs significantly from the models employed for South China and Qinghai–Tibet, suggesting variations in geological background, earthquake-resistant structures, and seismic resilience of society between the Taiwan region and mainland China. Moreover, a comparison with the U.S. Geological Survey model for the Taiwan region reveals that previous evaluations of the Taiwan region earthquakes greatly underestimated the number of fatalities.

Suitability Analysis of Ground Motion Prediction Equations for Western and Central Himalayas and Indo-Gangetic Plains

ABSTRACT Ground motion prediction equations (GMPEs) play a key role in seismic hazard assessment (SHA). Considering the seismo-tectonic, geophysical, and geotectonic characteristics of a target region, all the GMPEs may not be suitable in predicting the observed ground motion effectively. With a fairly large number of published GMPEs, the selection and ranking of suitable GMPEs for the design of logic trees in SHA for a particular target region have become a necessity of late. This paper presents a detailed quantitative evaluation of performance of 16 GMPEs against recorded ground motion data in two target regions, characterized by distinct seismo-tectonic, geophysical, and geotectonical nature. The dataset comprises 465 three-component spectral accelerograms corresponding to 122 earthquake events. The suitability of a GMPE is tested by two widely accepted data-driven statistical methods, namely, likelihood (LH) and log-likelihood (LLH) method. Different suites of GMPEs are shown suitable for different periods of interest. The results will be useful to scientists and engineers for microzonation and estimation of seismic design parameters for the design of earthquake-resistant structures in these regions.

Evolution and Implications of Changes in Seismic Load Codes for Earthquake Resistant Structures Design

Seismic load is a critical load that can trigger damage or collapse of structures, especially in earthquake-prone areas. The susceptibility of structures to seismic loads is influenced by factors related to soil characteristics and structural behavior. This paper comprehensively examines the development of Indonesian seismic code design parameters and their comparison with the current seismic code. The results of the analysis showed that the design spectral acceleration of short-period AD and long-period A1 SKBI 1987 and SNI 2002 increased with increasing PGA values, with a consistent pattern of SC < SD < SE. Unlike the previous two codes, design spectral acceleration AD and A1 SNI 2012 and SNI 2019 experience fluctuations in all types of soil. The ratio design spectral acceleration of AD and A1 SNI 2019 to KBI 1987 and SNI 2002 varies; there are up, fixed, and down for SC, SD, and SE soil conditions. The ratio of design spectral acceleration AD and A1 SNI 2019 to SNI 2012 designs also varies; this condition is due to changes in site coefficients. There were significant changes to the SKBI 1987 and SNI 2002 structural systems, especially the low and medium seismic levels. The increase in the seismic influence coefficient ratio of some cities varies for each type of soil and code. The increase in the 1970 PMI seismic coefficient was < 30% for all soil types, and the highest percentage increase occurred in SC soil types. The increase in seismic coefficient in SKBI 1987, SNI 2002, and SNI 2012 is more dominant in SE soil types. Doi: 10.28991/CEJ-2024-010-01-04 Full Text: PDF

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.

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.

Seismic Hazard Assessment in Maluku Province Using PSHA

On 10 January 2023, a strong earthquake with a moment magnitude (Mw) of 7.5 occurred in Banda Sea, Maluku Province. This earthquake caused casualties around the epicentre due to the building collapse which was not an earthquake-resistant structure. A high level of seismic vulnerability and non-standard infrastructure often result in large losses when earthquakes occur. Therefore, mapping of earthquake-prone areas needs to be carried out to optimize the mitigation efforts based on Peak Ground Acceleration (PGA) and Spectrum Acceleration (SA) values. In this paper, mitigation efforts are carried out by mapping earthquake-prone areas using Probabilistic Seismic Hazard Analysis (PSHA) which considers the potential of each complex earthquake source in Maluku Province. Input data was obtained from several earthquake catalogues such as Advanced National Seismic System (ANSS), International Seismological Center (ISC), and United States Geological Survey (USGS) which were processed and analyzed using the Matlab, ZMap, and R-CRISIS programs and mapped using the ArcMap program. The results of PSHA show that Maluku Province is a region with varying levels of earthquake vulnerability. The research results show that the distribution hazard value on PGA in Maluku Province reaches 0.02g to 0.48g for a return period of 500 years and 0.04g to 0.79g for a return period of 2,500 years and on SA for periods of 0.20 seconds and 1.00 second reaches 0.04g to 0.89g and 0.01g to 0.22g for a return period of 500 years and 0.07g to 1.48g and 0.02g to 0.35g for a return period of 2,500 years, respectively. The highest level of vulnerability is in the northern region including Seram Island, Way Apu Island and Ambon Island and the lowest level of vulnerability is in the eastern region including Aru Island.