Development of damage probability matrices based on Greek earthquake damage data

A comprehensive study is presented for empirical seismic vulnerability assessment of typical structural types, representative of the building stock of Southern Europe, based on a large set of damage statistics. The observational database was obtained from post-earthquake surveys carried out in the area struck by the September 7, 1999 Athens earthquake. After analysis of the collected observational data, a unified damage database has been created which comprises 180,945 damaged buildings from/after the near-field area of the earthquake. The damaged buildings are classified in specific structural types, according to the materials, seismic codes and construction techniques in Southern Europe. The seismic demand is described in terms of both the regional macroseismic intensity and the ratio αg/ao, where αg is the maximum peak ground acceleration （PGA） of the earthquake event and ao is the unique value PGA that characterizes each municipality shown on the Greek hazard map. The relative and cumulative frequencies of the different damage states for each structural type and each intensity level are computed in terms of damage ratio. Damage probability matrices （DPMs） and vulnerability curves are obtained for specific structural types. A comparison analysis is fulfilled between the produced and the existing vulnerability models.

Experimental validation of a signal-based approach for structural earthquake damage detection using fractal dimension of time frequency feature

This article extends a signal-based approach formerly proposed by the authors, which utilizes the fractal dimension of time frequency feature （FDTFF） of displacements, for earthquake damage detection of moment resist frame （MRF）, and validates the approach with shaking table tests. The time frequency feature （TFF） of the relative displacement at measured story is defined as the real part of the coefficients of the analytical wavelet transform. The fractal dimension （FD） is to quantify the TFF within the fundamental frequency band using box counting method. It is verified that the FDTFFs at all stories of the linear MRF are identical with the help of static condensation method and modal superposition principle, while the FDTFFs at the stories with localized nonlinearities due to damage will be different from those at the stories without nonlinearities using the reverse-path methodology. By comparing the FDTFFs of displacements at measured stories in a structure, the damage-induced nonlinearity of the structure under strong ground motion can be detected and localized. Finally shaking table experiments on a 1：8 scale sixteen-story three-bay steel MRF with added frictional dampers, which generate local nonlinearities, are conducted to validate the approach.

Revision of seismic design codes corresponding to building damagesin the “5.12” Wenchuan earthquake

A large number of buildings were seriously damaged or collapsed in the "5.12" Wenchuan earthquake. Based on field surveys and studies of damage to different types of buildings, seismic design codes have been updated. This paper briefly summarizes some of the major revisions that have been incorporated into the "Standard for classification of seismic protection of building constructions GB50223-2008" and "Code for Seismic Design of Buildings GB50011-2001." The definition of seismic fortification class for buildings has been revisited, and as a result, the seismic classifications for schools, hospitals and other buildings that hold large populations such as evacuation shelters and information centers have been upgraded in the GB50223-2008 Code. The main aspects of the revised GB50011-2001 code include: (a) modification of the seismic intensity specified for the Provinces of Sichuan, Shanxi and Gansu; (b) basic conceptual design for retaining walls and building foundations in mountainous areas; (c) regularity of building configuration; (d) integration of masonry structures and precast RC floors; (e) requirements for calculating and detailing stair shafts; and (f) limiting the use of single-bay RC frame structures. Some significant examples of damage in the epicenter areas are provided as a reference in the discussion on the consequences of collapse, the importance of duplicate structural systems, and the integration of RC and masonry structures.

Earthquake damage and loss estimation with Geographic Information System

The present paper first includes a brief discussion of GIS technology. Next, the various steps in a regional earthquake damage and loss analysis are discussed, with emphasis on their implementation in the GIS environment. Lastly, a software of WorldRisk which was completed recently are presented to illustrate GIS based global earthquake damage and loss estimation.

Comparison of strong-motion records and damage implications between the 2014 Yunnan M_S6.5 Ludian earthquake and M_S6.6 Jinggu earthquake

Serial destructive earthquakes have caused heavy casualties and economic losses to the city in southwestern of China. The Ludian Ms 6.5 earthquake and the Jinggu Ms 6.6 earthquake occurred in Yunnan province in 2014. There is a question of why the two events with almost the same level of magnitude caused differences in earthquake damage. To understand the uniqueness of the phenomenon, this paper focuses on the characteristics of the ground motions and post-earthquake field investigation for the two events. Firstly, we present an overview of the residuals between the Ludian earthquake and the Jinggu earthquake based on the YW06 Ground Motion Prediction Equation （GMPE）, and explain the unusual destructiveness of the strong ground motion. Then we analyze the ground motion recordings at selected typical station, based on the strong motion parameters： equivalent predominant frequency and Arias intensity. The result exhibits a good agreement with the Chinese seismic intensity scale. This study would be helpful to gain a better knowledge of the characteristics and variability of ground motions for Ms6 class earthquakes in China and to understand the implications to future earthquakes with similar focal mechanism and local condition.

Damage of 1975 Haicheng M_s7.3 earthquake in the Korean Peninsula and its effect on Kyushu,Japan

The 1975 Haicheng Ms7.3 earthquake affected whole Korean Peninsula and even Kyushu, Japan. In this paper isoseismal map of this earthquake was drawn for these areas by sorting out and analyzing data systematically collected, furthermore, the characteristics of the earthquake damage were discussed. In the northern Korean Peninsula, the intensity is V in great majority of this area except local area with intensity VI, and the damage is basically in accordance with typical characteristics of corresponding intensity grade. In the southern Korean Peninsula, the intensity is IV in large part of the area, however, in some big cities such as Seoul etc., not only high buildings shook strongly, but also some people appeared perceptions such as feeling dizzy and so on, and electrical service was interrupted on one or two districts because of transformer tripping. These phenomena could be caused by the effect of long-period wave generated from a large earthquake on far-field.

Performance of RC buildings after Kahramanmaraş Earthquakes: lessons toward performance based design

Two simultaneous earthquakes occurred in the Kahramanmaraş-Pazarcık and Kahramanmaraş-Elbistan districts of Turkey on February 6,2023,and with magnitudes of 7.7 and 7.6,respectively.These events caused the highest estimated loss recorded in Turkey within the last century from natural disasters.The key reason for the extensive loss was the proximity of eleven cities to the earthquake epicenters.Middle East Technical University teams investigated the building sites in Gaziantep,Kahramanmaras,Hatay,Adiyaman and Adana.The ground motion recordings revealed that in certain locations of Gaziantep,Kahramanmaraşand Hatay,the ground motion levels exceeded the maximum credible earthquake level defined for a return period of 2,475 years in the Turkish Earthquake Code.Residential building performance was investigated with respect to the construction year,which is a good indicator of compliance with modern seismic codes and inspection procedures.About 97%of the collapsed buildings were constructed prior to 2000,whereas over 5,000 buildings,which were built after 2000,collapsed or required urgent demolition.Most of the buildings with minor or greater structural damage sustained heavy infill wall damage rendering occupancy impossible.Aside from damage in older construction with significant structural deficiencies,the damage in some of the more recent and better constructed buildings was observed to be surprisingly poor.This can be attributed to the level of ground motion,significant ductility demands,poor material and workmanship and damage to non-structural elements.With the estimated total loss of above 100 billion dollars and over 50,000 casualties,the current seismic design criterion based on ductility and acceptance of structural damage should be re-evaluated to ensure a more resilient urban environment in high seismic regions.

Impact of intensity and loss assessment following the great Wenchuan Earthquake

The great Wenchuan Earthquake occurred on May 12, 2008 in the Sichuan Province of China, and had a magnitude of 8.0. It is the most serious earthquake disaster in China since the great Tangshan Earthquake （Ms=7.8, July 28, 1976）. According to official reports, there were 69,225 deaths, 379,640 injuries and 17,939 missing as of Aug. 11, 2008. The China Earthquake Administration quickly sent hundreds of experts to the field immediately after the event, to investigate the damage and assess the economic losses. This paper emphasizes the impact of seismic intensity and presents a preliminary loss assessment. A brief description of the geological features of the affected region is provided, followed by a summary of the earthquake damage. An isoseismal map is developed that shows that the high intensity region is distributed like a belt around the seimogenic fault, and that the epicentral intensity reached Ⅺ （Chinese Intensity Scale, similar to the Modified Mercalli Scale）. The direct economic loss resulting from the earthquake is 692 billions RMB （about 100 billions US$）.

Earthquake risk assessment for Istanbul metropolitan area

The impact of earthquakes in urban centers prone to disastrous earthquakes necessitates the analysis of associ- ated risk for rational formulation of contingency plans and mitigation strategies.In urban centers,the seismic risk is best quantified and portrayed through the preparation of'Earthquake Damage and Loss Scenarios.'The components of such scenarios are the assessment of the hazard,inventories and the vulnerabilities of elements at risk.For the development of the earthquake risk scenario in Istanbul,two independent approaches,one based on intensities and the second on spectral displacements,are utilized.This paper will present the important features of a comprehensive study,highlight the method- ology,discuss the results and provide insights to future developments.

Field survey around strong motion stations and its implications on the seismic intensity in the Lushan earthquake on April 20,2013

The Ms7.0 Lushan earthquake on April 20, 2013 is another destructive event in China since the Ms8.0 Wenchuan earthquake in 2008 and Ms7.1 Yushu earth- quake in 2010. A large number of strong motion recordings were accumulated by the National Strong Motion Obser- vation Network System of China. The maximum peak ground acceleration （PGA） at Station 51BXD in Baoxing Country is recorded as -1,005.3 cm/s2, which is even larger than the maximum one in the Wenchuan earthquake. A field survey around three typical strong motion stations confirms that the earthquake damage is consistent with the issued map of macroseismic intensity. For the oscillation period 0.3-1.0 s which is the common natural period range of the Chinese civil building, a comparison shows that the observed response spectrums are considerably smaller than the designed values in the Chinese code and this could be one of the reasons that the macroseismic intensity is lower than what we expected despite the high amplitude of PGAs. The Housner spectral intensities from 16 stations are also basically correlated with their macroseismic intensities, and the empirical distribution of spectral intensities from Lushan and Wenchuan Earthquakes under the Chinese scale is almost identical with those under the European scale.

Information system for emergence decision on the protection against earthquake and disaster reduction in Shanghai City──Application of GIS

For meeting the need of rapid development of economy in Shanghai and the protection against earthquake and disaster reduction in the mega city, it is necessary to build a information system for emergence decision on the protection against earthquake and disaster reduction in the city. In this paper, GIS is applied to 'the information system for emergence decision on the protection against earthquake and disaster reduction in Shanghai City (Baoshan experiment region)'. We introduce to the structure and effect of each functional module in this information system. This information system consists of 7 functional modules:background information of seismology and geology, subsystem for rapid evaluation of damage loss from earthquake, subsystem for the decisive information on earthquake emergence, information query, maintenance and management of system, help, quit. The key parts of this information system are the subsystem for rapid evaluation of damage loss from earthquake and the subsystem for the decisive information on earthquake emergence. Also, this paper introduces to the application of technology of color infra-red aerial photograph remote sensing to this information system.

Nucleation of earthquakes and its implication to precursors

The recent argument about nucleation phase of earthquakes reminds us to completely study the concept of earthquake nucleation. The original meaning of nucleation includes concentration, nucleation and initiation of the eruptive processes. Thus, it is needed to discuss how to exactly translate the word 'nucleation' into Chinese in different fields. The basic concept of earthquake nucleation refers to microcrack concentration in rock. It causes local weakening and instability of the rock. The narrow sense of nucleation theory of friction constitutive is significant in friction of fault surfaces, but should not abuse everywhere unconditionally. In terms of thermodynamics, nucleation actually means the variety processes of multiple state parameters of rock. The nucleation is a project that covers multiple courses. In this paper, the studies of damage theory, fracture, earthquake rupture dynamics and constitutive of friction and their implication to earthquake nucleation are remarked. The recently developments are introduced, including the influence of tectonic on the earthquake nucleation process, the method of measuring medium anisotropy, especially shear wave splitting led by concentration and orientation of microcracks. and the experimental study of remote sensing of infrared and microwave radiation related to the nucleation, etc. This paper also discusses the characteristic of large earthquake nucleation, and the implication of above studies to precursors of Strong earthquakes.

The inverse study of crustal damage state with gravity data in frequency domain

ＴｈｅｉｎｖｅｒｓｅｓｔｕｄｙｏｆｃｒｕｓｔａｌｄａｍａｇｅｓｔａｔｅｗｉｔｈｇｒａｖｉｔｙｄａｔａｉｎｆｒｅｑｕｅｎｃｙｄｏｍａｉｎＹＯＮＧＺＨＩＺＨＡＮＧ１）（张永志）ＷＥＮＰＩＮＧＷＡＮＧ１）（王文萍）ＷＥＩＦＥＮＧＬＩＡＮＧ１）（梁伟...

Seismic performance of cable-sliding friction bearing system for isolated bridges

During past strong earthquakes, highway bridges have sustained severe damage or even collapse due to excessive displacements and/or very large lateral forces. For commonly used isolation bearings with a pure friction sliding surface, seismic forces may be reduced but displacements are often unconstrained. In this paper, an alternative seismic bearing system, called the cable-sliding friction bearing system, is developed by integrating seismic isolation devices with displacement restrainers consisting of cables attached to the upper and lower plates of the bearing. Restoring forces are provided to limit the displacements of the sliding component. Design parameters including the length and stiffness of the cables, friction coefficient, strength of the shear bolt in a fixed-type bearing, and movements under earthquake excitations are discussed. Laboratory testing of a prototype bearing subjected to vertical loads and quasi-static cyclic lateral loads, and corresponding numerical finite element simulation analysis, were carried out. It is shown that the numerical simulation shows good agreement with the experimental force-displacement hysteretic response, indicating the viability of the new bearing system. In addition, practical application of this bearing system to a multi-span bridge in China and its design advantages are discussed.

Some considerations on the physical mea-sure of seismic intensity

The study on seismic intensity can be traced prior to the time that modern seismology was established. In its early stage the seismic intensity was designed to serve as a measure in scaling the severity of earthquake damage to civil engineering and environmental structures. Also the seismic intensity is usually assigned by engineers and seismologists with one or two characteristic parameters of earthquake ground motions to reflect earthquake damage potential so as to be able to serve as an input earthquake load for seismic design of structures. So choosing a proper parameter to reflect the action of seismic intensity is the main objective of the research on physical measure of seismic intensity. However, since various kinds of structures have quite different damage mechanisms, there will exist great differences in damages to different structures located at the same area during the same earthquake. Particularly, in some cases, quite different damages have happened even to the structures of same kind due to many other factors such as different construction materials, different configurations or on the different types of sites where structures located. In addition, the ground motion parameters, which result in damage to structures, are not the single peak value of ground motion. Hence, this paper emphasizes that the research on new physical measure of seismic intensity should not only consider the structural characteristics but also take into account other parameters such as duration, energy of ground motion and so on. In particular, as the physical measures of intensity, different ground motion parameter should be adopted for different structures.

Numerical simulation of damage in high arch dam due to earthquake

Based on the assumption that concrete is macroscopic homogeneous,the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesos-cale.The bilinear damage evolution model and the damage evolution model expressed in power function with descending section are adopted to combine with the Mohr-Coulomb criterion with tension cut-off to investigate the crack development and fracture mode of high arch dams under the action of an earthquake.The analysis result of a high arch dam in China under design shows that cracks that take place in concrete are caused by excessive tensile stress.The cracks initiate at the middle of the dam top and distribute at the upper half of the dam while the rest of the parts remain intact.This conclusion agrees with the model test result.

Assessing Potential Earthquake Loss in Me′rida State, Venezuela Using Hazus

The focus of the Hazus earthquake model has been largely U.S. centric due to a lack of standardized building-infrastructure data formats applicable elsewhere.In a combined effort between FEMA Region VIII and the Universidad de Los Andes, Venezuela, the present study uses the Hazus 2.1 software to simulate earthquake loss estimations for Venezuela. Population totals and demographic distributions were developed using Oak Ridge National Labs Landscan 2008 population data and the census 2011 for Venezuela. The accuracy of the model was further enhanced for Me′rida State, located in western Venezuela, by collecting, incorporating, and developing region and specific inventories including soil maps, liquefaction and landslide susceptibility studies, demographic data, and building inventory information. We used USGS Shake Maps scenarios for two potential earthquake events with peak ground accelerations proposed within Performance Based Seismic Engineering of Buildings, VISION 2000 recommendations. The region has not witnessed an earthquake with a magnitude greater than M 7 in the last120 years. Given the historical record of seismicity and the seismotectonics in the region, it becomes increasingly important to understand the potential implications from moderate to large earthquakes in Me′rida State, Venezuela.

A method for examining the seismic performance of steel arch deck bridges

To examine the seismic resistance performance of a steel arch bridge during a strong earthquake,an approach is proposed in this paper to determine the ultimate strain of an arch rib using the static elasto-plastic large deformation theory.A steel fixed-end deck arch bridge with a span length of 200 m was used as an example in this study.The ultimate strain of the arch rib was calculated using the elasto-plastic finite element model.The seismic responses of the arch bridge exposed to strong earthquakes in two and three directions were also simulated.Moreover,the effect of earthquake motion in the lateral direction on the elasto-plastic earthquake response was discussed,and the seismic resistance of the structure was analyzed.The results show that steel arch bridges have preferable seismic resistance under strong earthquake conditions.While lateral earthquake motion has some influence on the damage to an arch bridge,it has little effect on the displacement,axial force,and bending moment responses of the arch rib.It is feasible to examine the seismic performance of the arch bridge by ascertaining the out-of-plane and in-plane earthquake responses of the bridge.