Earthquake Response Analysis Research Articles

Study on Earthquake Response Analysis of Reinforced Concrete Masonry Structure

According to the analysis of a six-story reinforced concrete masonry building model with the methods of nonlinear time history analysis, the seismic performance of structure has been studied in this paper. The interstory shear-deformation and stiffness of linear elastic model is established. The availability of the analysis model, hysteretic model and relevant parameters adopted and the computation program developed are verified. The longitudinal deformation of structure is bigger than the lateral deformation under different earthquake waves, from this it can be showed that longitudinal seismic performance is smaller than lateral wall; for seven-story concrete block building with core-and tie-columns, the requirement of the seismic fortification intensity can be met. The analysis of this paper provides a reference for reinforced concrete block buildings.

Study on Dynamic Calculation Method for Pile Supporting Structure with One Layer Prestressed Anchor

A dynamic calculation model of the pile supporting structure with one layer prestressed anchor for the slope is proposed in this paper. The prestressed anchor is regarded as the elastic support of the pile body. According to the theory of one-dimension elastic wave propagation, the interaction between the pile and the soil is obtained. Then the motion equation of the pile-prestressed anchor is established based on the dynamic interaction. The analytical solutions are obtained. In addition the proposed method is applied to a project case to carry out the seismic analysis and design of the pile supporting structure with one layer prestressed anchor. The calculation method provides a theoretical basis for earthquake response analysis and seismic design of the pile supporting structure with one layer prestressed anchor.

Simplified Model of High-Rise Isolated Structure for Earthquake Response Analysis

Kelly and Xiyuan Zhou research on upper single-degree-of–freedom model of regular isolated building, and give necessary computing formulas. For various middle or low isolated building, the result is satisfied by using the model. Recently isolation technique was applied to high-rise buildings. For isolated building systems with large aspect ratio, high-order mode parts of upper structure can not be ignored. It brings large errors to use single-degree-of–freedom model. In the paper, according to the equivalent rules of equal structure period and total base shear, the computing formula of structure parameters is deduced. After numerical analysis for some regular buildings, a simplified method for equivalent model is given. By analyzing the earthquake responses of equivalent model and original structure, it is proved that the equivalent method is simple and feasible.

Performance of a Rigid Frame Arch Bridge under Near-Fault Earthquake Ground Motion

During May 12th 2008 Wenchuan earthquake with the magnitude of 8.0, a 4-span rigid frame arch bridge named as Xiaoyudong Bridge which situated close to the epicenter was hit by strong ground motion and was severely damaged. The earthquake response analysis of the bridge was made using FE software MIDAS based on recorded ground motion during the Wenchuan earthquake in this paper. The study showed that the main and minor arch legs on the both ends piers were weak links which may be damaged firstly under strong ground motion. The next damage at the pier with weakest horizontal stiffness is one of the important reasons causing the bridge collapsed. This paper will introduce our work on those respects and some drawn conclusions.

Landslides on ancient embankments in the Kinki district (Japan): Strong motion seismoscope of the 1596 Keichou-Fushimi earthquake

Landslides on ancient embankments, burial mounds of Imashiro-zuka and Nishimotome-zuka, induced by historical earthquakes related to the tectonic movement of active fault systems located between northern Osaka and Kobe, are discussed. The geological conditions of the foundation of the mounds, the lithology, stiffness, and the position of the mound relative to the fault systems, contributed to the collapse of the mounds. Obvious interior structures of landslides revealed the inherent deformation process, and provided significant insight into landslide mechanisms. Rapid increasing pore water pressure was necessary to facilitate sliding along the almost horizontal slip surfaces developed in the main part of the landslide bodies on the Imashiro-zuka mound. Liquefaction analysis using both the results of dynamic triaxial compression tests and earthquake response analysis showed liquefaction in the foundation of the mound was a possible landslide mechanism on the Nishimotome-zuka mound. Landslides of embankments are unavoidable over long periods of time if any weaknesses are present at the foundation of the construction. The total quality of an artificial soil structure very much depends on the conditions of its foundation bed. Today, these ancient burial mounds in the Kinki district are located in both rural and urban regions, and landslides on these mounds provide unique information about issues related to the long-term stability of modern large-scale construction activities.

Enhanced reduced model for elastic earthquake response analysis of a class of mono-symmetric shear building structures with constant eccentricity

An enhanced reduced model is proposed for elastic earthquake response analysis of a class of mono-symmetric shear building structures with constant eccentricity. The proposed reduction method consists of two parts. The first stage is the construction of a reduced structural model with the degrees of freedom at representative floor levels only. In this stage, an inverse eigenmode-problem formulation is used to guarantee the limited equivalence between the original model and the reduced model. The reduced model is constructed so as to have the same fundamental natural frequency and the same lowest-mode component ratios at the representative floor levels as those of the original model. The second stage is the transformation of earthquake input forces into a set of reduced input forces. This transformation utilizes the static equivalence of lateral-torsional stiffness between these two models and is introduced to enhance the accuracy level of the reduced model. Several examples of a three-dimensional mono-symmetric ten-story shear building model with constant eccentricity are presented to demonstrate the validity and accuracy of the proposed reduction method for earthquake response analysis.

Earthquake Response Analysis of Japanese Traditional Wooden Structures Considering Member Aging

This paper examines the seismic performance of Japanese traditional wooden structures considering stiffness and strength aging changes in old structural members. In strength and embedding testing done to evaluate the strength properties of old structural members, results showed that zelkova has a Young’s modulus similar or larger than new members. In nonlinear earthquake response analysis for a Kiyomizudera model based on test results, maximum angle response of columns was decreased reflecting old zelkova stiffness and strength.

Dynamic Analysis of the Superstructure-Pile Foundation-Soil Interaction System under Earthquake Based on Fuzzy Theory

Based on frequency domain method, the seismic responses of the superstructure-pile foundation-soil system are studied taking the dynamic soil-structure interaction into consideration. For analyzing the earthquake response of cylindrical pile foundation, earthquake response analysis of three-dimensional system of pile foundation-soil-superstructure simplify two-dimensional question. The dynamic responses of the interaction system under EI-Centro ground motion excitation are evaluated by using secondary development of the large general finite analysis software Abaqus. It is shown that pile foundation is more anti-seismic and that pile foundation flexibility can improve the structural basic cycle. Based on a comprehensive assessment theory, soil-superstructure interaction problem under Earthquake is analyzed by second-level evaluation of comprehensive evaluation. By applying comprehensive evaluation method fuzzy theory model of soil-superstructure interaction is built. It is show that fuzzy mathematics method is appropriate for this kind of soil-superstructure interaction problem.

Elasto-Plastic Earthquake Response Analysis of High-Speed Railway Bridge Fabricated Isolation Bearings

Basin rubber bearings are frequently used in high-speed railway bridge or passenger special line railway bridge, lead rubber bearings (LRB) are infrequently used in those railway bridges nowdays, the study on earthquake-resistant capability of railway bridge fabricated isolation bearing - the intelligent and functional structure - would be beneficial in engineering practices. Elasto-plastic earthquake responses of high-speed railway bridges fabricated LRB are studied by means of the finite element program, earthquake responses of railway bridges under high-speed vehicles and different earthquake action fabricated and unfabricated isolation bearing are calculated respectively. The results show that: plastic hinge will develop at the bottom of piers in regard to railway bridges with mid-high and low pier; LRB can reduce displacement and inner forces of structures and improve earthquake-resistant capability of structures effectively.

DAMAGE OF REINFORCED CONCRETE BUILDINGS DURING THE 1923 GREAT KANTO EARTHQUAKE BASED ON DYNAMIC CHARACTERISYICS

In this paper, we analyzed the damage of reinforced concrete buildings due to the 1923 great Kanto Earthquake in the City of Tokyo based on the dynamic analysis of a specified building that was studied in the damage investigation reports. Earthquake response analysis was conducted using the restoring force characteristics of the building at that time. Seismic ground motion predicted at the building site for the 1923 great Kanto Earthquake was used. As a result, the relationship between the damage criteria by investigation reports and damage analysis data confirmed that the analysis method was useful to estimate the damage and seismic performance of the reinforced concrete building at that time.

3 DIMENSIONAL EARTHQUAKE RESPONSE ANALYSES USING TIME DOMAIN ENERGY TRANSMITTING BOUNDARIES FOR 2 DIMENSIONAL IN-PLANE AND ANTI-PLANE PROBLEMS

Although the energy transmitting boundary is accurate and efficient for the FEM earthquake response analysis, it could be applied in the frequency domain only. In the previous papers, the author proposed an earthquake response analysis method using the time domain energy transmitting boundary for 2 dimensional problems. In this paper, this technique is expanded for 3 dimensional problems. The inner field is supposed to be a hexahedron shape and the approximate time domain boundary is explained, first. Next, 2 dimensional anti-plane time domain boundary is studied for a part of the approximate 3 dimensional boundary method. Then, accuracy and efficiency of the proposed method are confirmed by some linear and nonlinear problems.

NON-DESTRUCTIVE TEST FOR INTERNAL LOSS OF COLUMNS USING ELECTROMAGNETIC RADIATION TEST FOR EVALUATING SEISMIC PERFORMANCE OF JAPANESE TRADITIONAL WOODEN STRUCTURE

This paper examined the validity of electromagnetic radiation test to find an internal loss in columns of Japanese traditional wooden temple, Kiyomizu, in Kyoto. First, the test was performed for the specimen. The results showed that the test was able to detect 10cm over internal loss. Secondly, the test was performed for the column of Kiyomizu and some deteriorated columns were found. Finally, the earthquake response analysis was conducted for the Kiyomizu model which was assumed internal loss. In the result, the internal loss which exist column bottoms has minor influence on the seismic performance of Kiyomizu.

A STUDY ON PREDICTION OF DAMAGE RATIO OF PUBLIC MANAGEMENT APARTMENT BUILDINGS DUE TO EARTHQUAKE BASED ON SEISMIC PERFORMANCE INDEX

In this paper, an earthquake response analysis model based on seismic performance indices is proposed to evaluate actual seismic performance of public management apartment buildings appropriately. Damage ratio of buildings are calculated using this proposed model and observed seismic ground motions during the 1995 Hyogo-ken Nanbu Earthquake. As a result, the relationships between an index of seismic ground motion and calculated damage ratio of buildings show good agreement with vulnerability functions based on actual damage data of buildings in the 1995 Hyogo-ken Nanbu Earthquake. Through this study, it is pointed out that damage ratio of buildings could be overestimated, if load carrying capacity which has not been considered in the seismic design is not properly evaluated. Additionally, it is shown that the effect of slit on reinforced concrete wall has a big influence on the damage ratio of buildings.

Semi-Active Control for Base Isolated Structure Using Response Evaluator Subjected to Long-Period Earthquake Ground Motion

This paper presents a response evaluator as a semi-active control method for base isolated building in long-period earthquake response analysis. The absolute acceleration of each story and relative displacement of an isolated layer are the input signals and switching parameter for the damping coefficient is the output signal of the response evaluator. The response evaluator is designed by a multilayered neural network, and a genetic algorithm is used to adjust the neural network parameters which decide the performance of the response evaluator. Four oil dampers are installed at the isolated layer and each damping coefficient of the dampers is set to different value to correspond to various characteristics of earthquake motions, then the total damping force of the isolated layer is multi-step values regardless of using the oil dampers with two-step damping coefficient. By the numerical simulation with the proposed semi-active control method, both the acceleration of each story and the displacement of isolated layer which are trade-off relations with each other are reduced compared with the acceleration in case of all damping coefficient small (soft) and the displacement of isolated layer in case of all damping coefficient large (hard).

STUDY ON EARTHQUAKE RESPONSE OF SLIGHTLY DAMAGED RC SCHOOL BUILDING DURING THE 2008 IWATE-MIYAGI NAIRIKU EARTHQUAKE

The earthquake response analyses of the Iwagasaki High School, the RC building of which was slightly damaged during the 2008 Iwate-Miyagi Nairiku Earthquake, are performed to examine the correspondence relation of the analysis result and the actual damage. In the analyses, the soil structure is estimated by performing the simulation analyses of the aftershock records obtained at this site, and the soil response during the main shock is analyzed using both the estimated soil model and the main shock record obtained at the JMA Kurikoma site near this building. The earthquake response analyses of the structure on the pile foundation considering the nonlinear interaction of the soil-pile-structure system are performed by continuously inputting the soil response during the main shock and the aftershocks to the 3-D model. For the model installed the lateral soil spring showing the resistance caused by the embedded footing beam, the maximum story drift angle of the structure in the part of main shock is in agreement with the value estimated on the basis of the actual damage. The predominant frequency of the model in the part of aftershocks is also in agreement with that estimated using the records. From these results, it is shown that the lateral soil spring influences the actual behavior of this building.

ADVANCED MODEL REDUCTION METHOD FOR ELASTIC EARTHQUAKE RESPONSE ANALYSIS OF SHEAR BUILDINGS WITH SETBACK

An advanced reduced model is proposed for elastic earthquake response analysis of shear building structures with setback. The proposed reduction method consists of two parts. The first stage is the construction of a reduced structural model with the degrees of freedom at representative floor levels only. The reduced model is constructed using an inverse eigenmode-problem formulation so as to have the same fundamental natural frequency and lowest-mode component ratios at the representative floor levels as the original model. The second stage is the transformation of earthquake input forces into a set of reduced input forces. This transformation is introduced to enhance the accuracy level of the reduced model.

Earthquake Response Analysis of Spherical Tanks with Seismic Isolation

Based on response spectrum theory, the earthquake response of the spherical tank with seismic isolation is investigated. Characteristics and calculation model of a laminated rubber bearing are introduced. In order to determine dynamic magnification factor, the dynamic behavior and the earthquake response of the seismic isolation spherical tanks are analyzed. The results show that the spherical tank of a key point displacement decreases and the control effect of velocity and acceleration is more obvious. The structural seismic performance of spherical tank can be improved significantly by applying seismic isolation.

SIMPLIFIED DYNAMIC MODEL FOR SEISMIC RESPONSE ANALYSIS OF 3-DIMENSIONAL MULTI-STORY STEEL MOMENT FRAMES WITH ECCENTRICITY

This research is concerned with the earthquake response of 3-dimensional multi-story steel moment frames with eccentricity. In this paper, we propose a simplified dynamic model for the frames. The model, which has six degrees of freedom for each story, is used to conduct earthquake response analyses. The results are compared with those from finite element method analysis using ABAQUS. It is clarified that the earthquake response of the frames is approximated through a numerical study using this model.

A BASIC STUDY ON TWO-DIMENSIONAL ELASTO-PLASTIC EARTHQUAKE RESPONSES IN ONE-MASS-SYSTEM FOR PEAK RESPONSE PREDICION

In this study, lateral two directional elasto-plastic earthquake response analyses with one-mass-system were conducted, which restoring force characteristics were elasto-perfectly plastic model and slipping model based on an analogy to the theory of plasticity. Peak displacement responses were examined with a view to its prediction by using equivalent linearization and elastic response spectrum. The model shown in this paper had the same initial natural period and yield strength in all the lateral direction. Therefore, anisotropic behaviors appeared in hysteresis loop in slipping model subjected to lateral two-directional cyclic loads. In this paper, two typical measured earthquake accelerations were adopted in calculations. As a result, a possibility was shown that the peak displacement responses in those two models were predicted within the same degree of precision by estimating substitute damping in each model.

Semi-Active Control for Base Isolated Structure Using Response Evaluator Subjected to Long-Period Earthquake Ground Motion

This paper presents a response evaluator as a semi-active control method for a base isolated building in long-period earthquake response analysis. The absolute acceleration of each story and the relative displacement of an isolated layer are the input signals and the switching parameter for the damping coefficient is the output signal of the response evaluator. The response evaluator is designed by a multilayered neural network, and a genetic algorithm is used to adjust the neural network parameters which determine the performance of the response evaluator. Four oil dampers are installed in the isolated layer and each damping coefficient of the dampers is set to a different value to correspond to the various characteristics of earthquake motions, then the total damping force of the isolated layer is multi-step values, regardless of whether using oil dampers with two-step damping coefficients. By the numerical simulation with the proposed semi-active control method, both the acceleration of each story and the displacement of the isolated layer, which are in a trade-off relationship with each other, are reduced compared with the acceleration in the case of all damping coefficients being small (Soft) and the displacement of the isolated layer in the case of all damping coefficients being large (Hard).