Earthquake Resistant Design Of 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.

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 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.

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.

New classification of soils by seismic properties for the building code in Uzbekistan

ABSTRACT The accurate assessment of soil conditions is crucial for ensuring the seismic safety of buildings and structures. The existing classification of soils in the building code of Uzbekistan has several drawbacks that affect the accuracy of the input parameters of soil properties, the determination of the seismic intensity of the ground, and the underestimation of external environmental factors that affect seismic intensity. In response to these shortcomings, this paper presents the results of long-term engineering geological, macroseismic, and geophysical studies conducted to assess the influence of ground conditions on seismic intensity parameters. Based on the findings, a new classification of soils according to seismic properties is proposed. The classification system considers the unique characteristics of each soil type and provides a more accurate representation of their seismic properties. The proposed classification system is expected to provide valuable insights for seismic hazard assessment and earthquake-resistant design of structures.

Nonlinear Static Analysis of Building with Different Aspect Ratio


 
 
 
 The earthquake resistant design of structures requires that systems ought to maintain, adequately, any ground motions of an depth that would arise for the duration of their construction or in their regular use. However floor motions are unique inside the consequences they have got on structural responses. The most accurate evaluation method for structures subjected to strong ground motions is the time history analysis . This evaluation entails the integration of the equations of motion of a multi-degree-of-freedom system, MDOF, within the time domain the usage of a stepwise answer which will constitute the real reaction of a structure. This technique is time-eating even though for application in all sensible functions. The necessity for faster techniques that could make certain a dependable structural assessment or design of structures subjected to seismic loading brought about the pushover analysis.
 Pushover analysis is based totally on the belief that systems oscillate predominantly inside the first mode or inside the decrease modes of vibration at some stage in a seismic occasion. This ends in a reduction of the multi-degree-of-freedom, MDOF machine, to an equivalent single-degree- of-freedom, ESDOF gadget, with properties expected by a nonlinear static evaluation of the MDOF system. The ESDOF device is then eventually subjected to a nonlinear time- history analysis or to a response spectrum analysis with consistent- ductility spectra, or damped spectra. The seismic demands calculated for the ESDOF device are converted through modal relationships to the seismic demands of the MDOF machine.
 The objective of this thesis record is to emphasise the use of non-linear static procedure i.e pushover analysis a seismic overall performance assessment of R.C frames .
 
 
 

Analytic Investigation of Hooked Stirrups on Seismic Behavior of Reinforced Concrete 3D Frame Buildings

Ensuring the safety and stability of buildings during earthquakes is of utmost importance. This can be achieved by assessing the seismic performance of reinforced concrete structures with consideration of design details. This study focused on the seismic behavior of reinforced concrete buildings by comparing the effects of two different types of stirrups, namely those with a 135° angled end-hook shape and straight hooks, with variation of concrete strength. Pushover analysis of a sample building was performed to determine the effect of hook shape on stirrup reinforcement with a constant volumetric ratio for various concrete strength classes. The results of the analysis indicated significant differences in concrete strength and seismic behavior between the two stirrup configurations. The hooked stirrups demonstrated superior energy dissipation capability and ductility, which led to better seismic performance compared to unhooked stirrups across varying levels of concrete strength. To extend the investigation, the study compared the Mander et al., Kent–Scott–Park, and Kappos–Konstantinidis concrete models with different concrete classes (C50-C25-C20-C16-C10). The findings emphasized the importance of stirrup configuration in the design of earthquake-resistant structures. The study concluded that RC structural performance with the 135-degree hooked concrete members exhibited much better behavior of the 90-degree members for the various concrete strength. In this way, it has been revealed the arrangement and detailing of reinforcement in the construction beams and columns improves the governing effect on seismic structural performance.

Seismic hazard assessment studies based on developed deterministic and probabilistic approaches for the central-east of Iran region

PurposeThis Study aims to present the seismic hazard assessment of the earthquake-prone eastern of Iran that has become more important due to its growing economic importance. Many cities in this region have experienced life and financial losses due to major earthquakes in recent years. Thus, in this study the seismic hazard maps and curves, and site-specific spectrums were obtained by using probabilistic approaches for the region.Design/methodology/approachThe seismotectonic information, seismicity data and earthquake catalogues were gathered, main active seismic sources were identified and seismic zones were considered to cover the potential active seismic regions. The seismic model based on logic tree method used two seismic source models, two declustered catalogues, three choices for earthquake recurrence parameters and maximum considered earthquakes and four ground motion predicting (attenuation) models (GMPE).FindingsThe results showed a wide range of seismic hazards levels in the study region. The peak ground acceleration (PGAs) for 475 years returns period ranges between 0.1 g in the north-west part of the region with low seismic activity, to 0.52 g in the south-west part with high levels of seismicity. The PGAs for a 2,475-year period, also ranged from 0.12 to 0.80 g for the same regions. The computed hazard results were compared to the acceptable level of seismic hazard in the region based on Iran seismic code.Originality/valueA new probabilistic approach has been developed for obtaining seismic hazard maps and curves; these results would help engineers in design of earthquake-resistant structures.

Artificial intelligence (AI)-assisted simulation-driven earthquake-resistant design framework: Taking a strong back system as an example

Traditional earthquake-resistant structural design considers only a limited number of factors, mainly elastic structural properties, to determine key design parameters. However, these parameters are often not optimal because they do not take into account the extensive plasticity expected in building structures during earthquakes. To address this issue, an artificial intelligence (AI)-assisted simulation-driven framework has been developed in this study. This framework can automatically output optimal design parameters while considering nonlinear structural response under strong earthquakes and a large number of input factors. The primary innovation of the proposed framework lies in the fusion and integration of nonlinear numerical simulation and AI tools for earthquake-resistant design of building structures, marking a promising trend in this field. The framework consists of two steps. In the first step, a database that consists of optimal design parameters and covers a wide range of design inputs will be created through numerical nonlinear response history analyses (NRHAs). In the second step, AI models will be created and trained based on the database to automatically output the optimal design parameters. To illustrate the basic components underlying the proposed framework, the determination of the height-wise distribution (denoted by Ψ) of the total design lateral force for a strong back system is taken as an example. A database of 1200 samples was created through NRHAs, and an artificial neural network (ANN) model was created, optimised, and trained. The developed ANN model yielded optimal Ψ with the majority of absolute errors within 1%, demonstrating the feasibility of the proposed AI-assisted simulation-driven earthquake-resistant design framework.

Simulation-Based Model-Updating Method for Linear Dynamic Structural Systems

The dynamic characteristics of buildings and their behavior under various dynamic loads play a crucial role in civil engineering applications, particularly for earthquake-resistant structural design. Employing a precise mathematical model of the structural system makes it possible to accurately predict the actual structural performance under dynamic loads, such as winds and earthquakes. Given this perspective, finite element model-updating approaches in structural systems have gained significant attention in recent decades. This paper proposes a simulation-based model-updating technique that utilizes measured free vibration responses to the correct structural parameters of multi-degree-of-freedom systems. A five-degree-of-freedom building model is subjected to shaking table tests to demonstrate the effectiveness of the proposed method. The experimental data for this method consists of the dynamic behavior of the system under the seismic excitation of the El Centro 1940 earthquake and the results of the free vibration tests. The MATLAB/Simulink parameter estimation tool is employed to establish a correlation between the analytical model and the measured dynamic response from the building model. Compared to the measured structural responses, the updated analytical model, which incorporates the proposed simulation-based model-updating technique, demonstrates high accuracy in predicting the responses through effective corrections of stiffness and damping coefficients.

Stress state and waves in the lithospheric plate simulation: A 3rd generation AI architecture

Natural disasters present ongoing risks to human life and the global economy, with climate change and environmental factors exacerbating these threats. This article introduces an innovative approach to earthquake prediction and modeling, utilizing a combination of modern mathematical techniques, data-driven methodologies, and artificial intelligence (AI). By integrating the finite element method and wavelet collocation method, our approach enables the solution of complex partial differential equations involving fractional derivatives. This integration provides a more accurate prediction of earthquake behavior by leveraging AI analysis of the resulting numerical solutions.Our advanced modeling technique enables three-dimensional earthquake modeling, surpassing the limitations of traditional methods and offering unprecedented insights. The comprehensive AI approach shows great potential for improving our understanding of earthquake behavior, facilitating the design of earthquake-resistant structures, and effectively mitigating the devastating impacts of earthquakes.This research significantly contributes to the field of disaster risk reduction and offers practical applications for both researchers and practitioners. By combining mathematical rigor, data-driven insights, and the power of AI, our next-generation approach opens new avenues for enhancing our preparedness and response to seismic events.

Perencanaan Ulang Struktur Portal Utama Gedung PT. Ferron Par Pharmaceuticals Cikarang Integrasi BIM (Building Information Modelling)

In development construction projects, the digitalization of excellent and mature construction planning is needed to obtain efficient and effective construction results and through the implementation of BIM integrated Structural Planning and Analysis(Building Information Modelling) expected in building planning PT. Ferron Pharmaceuticals Cikarang can minimize the occurrence of errors. The purpose of this final project is to re-design the building of PT. Ferron Pharmaceuticals Cikarang by integrating conventional planning methods into a based planning method BIM (Building Information Modelling) for efficiency structure and project visualitation on the project. The process used is quantitative descriptive by conducting a literature study to understand the basics of planning a high-rise building structure, then proceeding with integration based on SAP2000. The result of this paper is an earthquake-resistant structural design with the Sway Frame with modelling 3D that can be applied to tall buildings with high levels of security, reliability and earthquake resistance. The Finding of this re-design is the high efficiency of this structure in reducing earthquake resistance and can be used as a reference for planning earthquake resisitant buildings in the future.

Perencanaan Ulang Struktur Portal Utama Gedung PT. Ferron Par Pharmaceuticals Cikarang Integrasi BIM (Building Information Modelling)

In development construction projects, the digitalization of excellent and mature construction planning is needed to obtain efficient and effective construction results and through the implementation of BIM integrated Structural Planning and Analysis(Building Information Modelling) expected in building planning PT. Ferron Pharmaceuticals Cikarang can minimize the occurrence of errors. The purpose of this final project is to re-design the building of PT. Ferron Pharmaceuticals Cikarang by integrating conventional planning methods into a based planning method BIM (Building Information Modelling) for efficiency structure and project visualitation on the project. The process used is quantitative descriptive by conducting a literature study to understand the basics of planning a high-rise building structure, then proceeding with integration based on SAP2000. The result of this paper is an earthquake-resistant structural design with the Sway Frame with modelling 3D that can be applied to tall buildings with high levels of security, reliability and earthquake resistance. The Finding of this re-design is the high efficiency of this structure in reducing earthquake resistance and can be used as a reference for planning earthquake resisitant buildings in the future.

Determination of Empirical Correlations between Shear Wave Velocity and Penetration Resistance in the Canakkale Residential Area (Turkey)

One of the most important parameters used to determine the dynamic properties of soil layers is the shear wave velocity. In geotechnical earthquake engineering, the shear wave velocity is used to determine the shear modulus, which provides the input parameters for the design of earthquake-resistant structures. Although there are measurement methods used in field studies to determine the shear wave velocity, they may not be economical in some cases. In this study, the empirical correlations between the shear wave velocity and penetration resistance in sandy soils were investigated with the use of geotechnical and geoseismic data obtained within the scope of microzonation studies performed in the Canakkale residential area. The results of the study were compared with correlations obtained from previous studies, and the equation we produced showed a good ability to predict the shear wave velocity. In addition, it was determined that standard penetration resistance, without energy correction, provided a better correlation coefficient.

New Probabilistic Seismic Hazard Model for Nepal Himalayas by Integrating Distributed Seismicity and Major Thrust Faults

Nepal is one of the most seismically active regions in the world, as highlighted by the recent devastating 2015, Mw~7.8 Gorkha earthquake, and a robust assessment of seismic hazard is paramount for the design of earthquake-resistant structures. In this study, we present a new probabilistic seismic hazard assessment (PSHA) for Nepal. We considered data and findings from recent scientific publications, which allowed us to develop a unified magnitude homogenized seismicity catalog and propose alternative seismic source characterization (SSC) models including up-to-date parameters of major thrust faults like main frontal thrust (MFT) and main boundary thrust (MBT), while also considering existing SSC models and various seismic hazard modeling strategies within a logic tree framework. The sensitivity analyses show the seismic hazard levels are generally higher for SSC models integrating the major thrust faults, followed by homogenous volume sources and smoothed seismicity approach. The seismic hazard maps covering the entirety of Nepal are presented as well as the uniform hazard spectra (UHS) for five selected locations (Kathmandu, Pokhara, Biratnagar, Nepalganj, and Dipayal) at return periods of 475- and 2475-years considering Vs,30 = 760 m/s. The results obtained are generally consistent with most recent studies. However, a notable variability in seismic hazard levels and several discrepancies with respect to the Nepal Building Building Code NBC105: 2020 and global hazard model, GEM are noted, and possible causes are discussed.

Backbone model for predicting the shear behavior of geopolymer panels under diagonal tension tests

This study develops a novel backbone model based on a set of empirical equations to predict the shear performance of geopolymer wall panels under monotonic diagonal tension. The model describes a trilinear envelope which allows to predict the shear strengths and drifts at the diagonal cracking, peak and ultimate limit states of the geopolymer panels. A comprehensive experimental program comprising diagonal tension testing on 27 squat housing panels was considered for the model calibration, including three different concrete types and three web shear reinforcement ratios made of welded-wire mesh. Results showed that geopolymer concrete contribution to cracking and peak strengths of the panels can be set as 0.62fc′, drifts at 0.03%-0.05%, 0.20%-0.45% and 0.75%-0.85% are advised for the cracking, peak and ultimate limit states, and new efficiency factors of the web reinforcement can be fixed as 0.35–0.75 for geopolymer panels. In addition, a statistical analysis demonstrated the trustful fitting of the proposed model reaching average prediction-to-test ratios ranging from 0.8 to 1.2, average coefficients of variation of 15%, and average overpredictions close to 40%. The backbone model proposed here is intended to be a useful reference in a new preliminary performance-based framework for earthquake-resistant structural design of geopolymer concrete panels and low-rise walls controlled by shear deformations.

Bayesian analysis-based ground motion prediction equations for earthquake input energy

Earthquake energy-based procedures offer a promising alternative for seismic evaluation and earthquake-resistant design of structures. Accurate determination of earthquake energy demand and the provision of an adequate energy supply to the structural system are crucial for this approach. This is where the utilization of ground motion prediction equations (GMPEs) becomes essential in achieving accurate assessment of seismic demands on structures. However, most GMPEs primarily focus on determining spectral accelerations. This study proposes a methodology to derive GMPEs by combining the Fourier amplitude spectrum, the elastic input energy spectrum, and Bayesian regression analysis. These GMPEs estimate energy-based spectral values for interplate and intraslab earthquakes recorded in the firm ground of Mexico City. Furthermore, a mathematical expression is devised to determine correlation coefficients between energy-based spectral values for interplate and intraslab earthquakes, expanding the GMPEs' applicability. Finally, a probabilistic seismic hazard analysis is conducted using the proposed GMPEs and the correlation model.

Role of Nonlinearity in the Soil in Earthquake-Resistant Design of Structures

The nonlinearity of the soil may considerably affect the response of structures subjected to seismic events. This paper aims to show under which circumstances geometry, soil, and earthquake-type; the nonlinearity is important. A simple model based on a 1D shear column was developed to calculate the maximum shear strain (γ) in the soil subjected to earthquake excitation. It was found that γ is a function of peak ground acceleration PGA and the maximum horizontal ground displacement (∆). EC8 provides an expression for calculating ∆ that is independent of the soil thickness. It was found that this expression is conservative for shallow layers and underestimates γ for thick ones, as a result, improvements have been suggested. By performing several time history analyses, simple formulas are developed which enable the designer to assess when nonlinearity must be taken into account. Four curves based on soil thickness and peak ground acceleration have been introduced for different soil types (A, B, C, and D) using a limit value of γ = 10–4. These curves show that depending on the soil depth, the threshold acceleration of nonlinear soil behavior is around 0.48, 0.36, 0.29, and 0.10 m/s2 for soil types A, B, C, and D, respectively. Obviously, nonlinear analysis must be performed for shallow soil layers under moderate seismicity.

Development and experimental validation of finite element models for a prestressed lead extrusion damper

The emerging trend in earthquake-resistant structural design is to dissipate some part of the seismic input energy through energy-dissipating devices (EDDs). A prominent candidate to serve this purpose is the lead extrusion damper (LED), which dissipates seismic energy by the extrusion of lead through the displacement of a bulged shaft. The LEDs should be designed as they meet the demands of the host structural system. Hence, predicting the force–displacement relation and energy dissipation characteristics of the LED is essential. To serve this purpose, comprehensive three-dimensional finite element models (FEMs) were developed in this study to simulate the cyclic behavior of a prestressed LED. The methodology consisted of performing coupon tests, the development of FEMs, and experimental verification. Coupon tests were performed for lead and steel to simulate the nonlinear material behaviors better. The models were validated against the experimental results of the LED and a steel beam-to-column connection. In general, the adapted model satisfactorily captured the experimental results. The maximum differences in the maximum force and dissipated energy predictions were about 7.5% for the generated FEMs. In addition, the mean relative difference in predicting damper forces for eight LEDs selected from the literature was about 6%. The low relative differences between the models and experiments demonstrated that the adapted FEM could reliably estimate the cyclic response of the LEDs. It can be stated that the adapted three-dimensional finite element modeling strategy can be utilized robustly for design purposes.