Ufuk Hancilar

Rapid Earthquake Loss Assessment After Damaging Earthquakes

This article summarizes the work done over last decades regarding the development of new approaches and setting up of new applications for earthquake rapid response systems that function to estimate earthquake losses in quasi real time after an earthquake. After a critical discussion of relevant earthquake loss estimation methodologies, the essential features and the characteristics of the available loss estimation software are summarized. Currently operating near real time loss estimation tools can be classified under two main categories depending on the size of area they cover: Global and Local Systems. For the global or regional near real time loss estimation systems: GDACS, WAPMERR, PAGER, ELER and SELENA methodologies are. Examples are provided for the local rapid earthquake loss estimation systems including: Taiwan Earthquake Rapid Reporting System, Real-time Earthquake Assessment Disaster System in Yokohama, Real Time Earthquake Disaster Mitigation System of the Tokyo Gas Co., IGDAS Earthquake Protection System and Istanbul Earthquake Rapid Response System.

Pan-European seismic risk assessment: a proof of concept using the Earthquake Loss Estimation Routine (ELER)

One of the key objectives of the new EU civil protection mechanism is an enhanced understanding of risks the EU is facing. Developing a European perspective may create significant opportunities of successfully combining resources for the common objective of preventing and mitigating shared risks. Risk assessments and mapping represent the first step in these preventive efforts. The EU is facing an increasing number of natural disasters. Among them earthquakes are the second deadliest after extreme temperatures. A better-shared understanding of where seismic risk lies in the EU is useful to identify which regions are most at risk and where more detailed seismic risk assessments are needed. In that scope, seismic risk assessment models at a pan-European level have a great potential in obtaining an overview of the expected human and economic losses using a homogeneous quantitative approach and harmonized datasets. This study strives to demonstrate the feasibility of performing a seismic risk assessment at a pan-European level with an open access methodology and using open datasets available across the EU. It also aims at highlighting the challenges and needs in datasets and the information gaps for a consistent assessment of seismic risk at the pan-European level. Results are expressed as expected casualties and economic losses for a return period of 475-year. The study constitutes a “proof of concept” that can complement the information provided by Member States in their National Risk Assessments. Its main contribution lies in pooling open-access data from different sources in a homogeneous format, which could serve as baseline data for performing more in depth risk assessments in Europe.

Empirical Fragility Functions based on Remote Sensing and Field Data after the 12 January 2010 Haiti Earthquake

In the immediate aftermath of the Haiti earthquake of 12 January 2010, a joint study for the estimation of damage to the building stock based on aerial images was carried out by UNITAR-UNOSAT, the EC-JRC, and the World Bank/ImageCAT in support of the PDNA. A targeted field campaign was led to the areas affected by the disaster in collaboration with the CNIGS with the purpose of validating the remote sensing based damage assessment. These two methodologies for collecting data resulted in two data sets of the damaged buildings categorized according to the EMS-98 damage grades. In the present study, fragility functions for different urban zones of Haiti, that is, low-, medium-, and high-density built-up and shanty zones, are developed from the remote sensing damage assessment data. Structural fragilities for buildings grouped with respect to material type and number of stories are derived on the basis of field damage data.

Investigation of the Rail-Induced Vibrations on a Masonry Historical Building

Increasingly historic masonry buildings are subjected to higher levels of traffic and rail vibrations due to urbanization and population growth. Deterioration and destabilisation of these buildings may result, especially if they were previously damaged (e.g. earthquakes or settlement problems). To better understand building response, vibration measurements were conducted on the Little Hagia Sophia Mosque, located adjacent to Istanbul’s Sirkeci-Halkali railway line. Transport-induced vibrations were recorded at several points on the ground and building. Attenuation characteristics in the ground and amplification features on the building were examined. Peak particle velocities often exceeded previously established thresholds for human perception and in some cases for structural damage. These are evaluated with respect to the building’s condition.

Development of ground-shaking maps for the Sultanate of Oman

This study presents research toward the development of ground-shaking maps after a real earthquake, or for scenario earthquakes originating from seismic sources within and around the Sultanate of Oman. Major important earthquake sources that are important for the Sultanate of Oman are the Makran zone, the Zagros zone, the Zendan-Minab system, the Oman Mountain zone, the Owen fracture zone and the Gulf of Aden zone. The earthquakes that take place on these zones, particularly those from Makran, already resulted and are likely to result in ground-shaking levels that may be significant for the country. The hazard module of software package ELER was customized for use in the development of shake maps in the Sultanate of Oman. For this purpose, (1) major active faults and systems within and around Oman were defined and implemented; (2) ground-motion prediction equations suitable for use and representative of tectonic conditions in Oman were identified and implemented; (3) the effect of local site conditions in resulting ground-shaking levels was attended by implementing the Vs30 maps into ELER methodology; and (4) scripts were developed for the consideration of ground-motion data coming from strong motion stations and from seismometers in and around Oman. They were used in the adjustment of ground-motion distribution maps, such as peak ground acceleration, peak ground velocity and spectral acceleration maps produced using ground-motion prediction equations. Example runs of different scenarios reflecting the use of newly adopted information are presented.

Empirical fragility assessment after the January 12, 2010 Haiti earthquake

In the immediate aftermath of the Haiti earthquake of 12 January 2010, a joint work for the estimation of damage to the building stock based on aerial images was carried out by the United Nations Institute for Training and Research (UNITAR) Operational Satellite Applications Programme (UNOSAT), the European Commission (EC) Joint Research Centre (JRC) and the World Bank/ ImageCAT in support of the Post Disaster Needs Assessment and Recovery Framework (PDNA). A targeted field campaign was led to the areas affected by the disaster in collaboration with the Centre National d’Information Geo-Spatial (CNIGS) representing the Government of Haiti with the purpose of validating the remote sensing based damage assessment. These two methodologies for collecting data resulted in two data sets of the damaged buildings categorised according to European Macroseismic Scale (EMS-98) damage grades. The present study makes use of these data for the derivation of empirical fragility functions. Fragility functions for different urban zones of Haiti, i.e. low-, mediumand high-density built-up zones and shanty zone, are developed from the remote sensing damage assessment data. Structural fragilities for buildings grouped with respect to material type and number of stories are derived on the basis of observed damage data collected through field surveys.

Seismic Assessment and Rehabilitation of Historical Unreinforced Masonry (URM) Buildings in Istanbul

The aim of the study is to evaluate the earthquake performance of two historical buildings located in Istanbul exposed to a M+7 earthquake expected to hit the city and, to propose solutions for their structural rehabilitation and/or strengthening. Both of the buildings are unreinforced clay brick masonry (URM) structures built in 1869 and 1885, respectively. The first building is a rectangular-shaped structure rising on four normal floors and the second one has an L shape with one basement floor and three normal stories. They survived the 1894, Ms7.0 Istanbul earthquake, during which widespread damage to URM buildings took place in the city [3]. No information could be reached whether and in what way they were affected by this earthquake. Although, there can be seen some cracks on some perimeter as well as secondary walls of the buildings. Determination of the site-specific performance assessment and retrofit design basis earthquake ground motion is achieved through deterministic seismic hazard assessment. The buildings are modeled and analyzed as a three-dimensional assembly of finite elements using SAP2000 v11 (Static and Dynamic Finite Element Analysis of Structures) [8] software package. The linear dynamic analysis procedure of FEMA 356 and ASCE41-06 [1, 2] is followed for the seismic assessment of the buildings. In order to improve earthquake resistance of the buildings, reinforced cement jacketing of the main load-carrying walls and application of fiber reinforced polymer (FRP) bands to the secondary walls are proposed.

PARAMETRIC EVALUATION OF SEISMIC RETROFITTING TECHNIQUES APPLIED TO THE PUBLIC SCHOOL BUILDINGS IN ISTANBUL

Seismic performance evaluation and retrofitting / strengthening of 142 public school buildings in Istanbul have been implemented within the World Bank funded Istanbul Seismic Risk Mitigation and Emergency Preparedness (ISMEP) Project. The most common retrofitting techniques applied to the school buildings following their seismic performance assessments in accordance with the national (Turkish Earthquake Resistant Design and Retrofitting Code-2007, [3]) and the international standards (FEMA273, FEMA356, ASCE41-06) are the reinforced concrete jacketing of the existing columns and shear walls and, the construction of new shear walls. In this study, a parametric evaluation of the retrofitting techniques applied to the school buildings is carried out. The amounts of RC jacketing (i.e. concrete and steel quantities) and the number of the newly added shear walls are statistically evaluated and the changes in the stiffness, fundamental period and the mass of the buildings as well as the resulting base shears are compared with the existing cases.