Dominik H. Lang

RISe: Illustrating Georeferenced Data of Seismic Risk and Loss Assessment Studies Using Google Earth

Predicting the consequences of large earthquakes to the built environment is of high importance for disaster control, civil protection and emergency planning. A number of software tools are now available to estimate physical building damage and associated losses in terms of casualties and economic losses. In recent years, SELENA, a seismic risk and loss assessment software which makes use of the capacity spectrum method (CSM), has been developed into a widely applicable tool. Since SELENA functions independently from a Geographic Information System, we developed RISe (Risk Illustrator for Selena), a stand-alone tool that illustrates SELENA files in Google™ Earth. RISe is customized to the SELENA file structure and allows easy conversion of all geographically referenced files such as building inventory data, soil conditions, ground motion values, as well as final risk and loss results. RISe is distributed as public domain open-source software that allows the user to take full advantage of Google™ Earths features including high-resolution satellite images from nearly every built environment worldwide.

Comparing Empirical and Analytical Estimates of Earthquake Loss Assessment Studies for the City of Dehradun, India

Very few earthquake risk studies exist for cities on the Indian subcontinent. The few studies that do exist typically focus on intensity as the parameter to describe the expected ground motion during an earthquake and on damage observations to represent building vulnerability. In contrast to these empirical studies, analytical loss computations, which are based on capacity spectrum methods (CSM), have recently become popular and are gaining wide acceptance. Analytical damage and loss computations have been conducted for the test bed Dehradun, a city of 500,000 inhabitants in the foothills of the Himalayas (northern India), and then compared with loss estimates from empirical studies recently performed for the city. The study illustrates the problems associated with trying to generate intensity-compatible ground motion estimates and comparing the damage and loss estimates of both approaches.

A Comparative Study of Design Base Shear for RC Buildings in Selected Seismic Design Codes

Modern seismic building design codes tend to converge on issues of design methodology and the state-of-the-art. However, significant differences exist in basic provisions of various codes. This paper compares important provisions related to the seismic design of RC buildings in some of the major national seismic building codes viz. ASCE 7, Eurocode 8, NZS 1170.5, and IS 1893. Code provisions regarding the specification of hazard, site classification, design response spectrum, ductility classification, response reduction factors, and minimum design base shear are compared and their cumulative effect on design base shear is studied. The objective component of overstrength contributed by the material and load factors is considered to normalize the design base shear. It is observed that every code has merit over the other codes in some aspect. The presented discussion highlights the major areas of differences which need attention in the process of harmonization of different codes of the world.

An Analytical Study on the Seismic Vulnerability of Masonry Buildings in India

Two analytical models for unreinforced masonry (URM) buildings are proposed with the aim to simulate their seismic response and to estimate corresponding vulnerability functions. The proposed models are implemented in SAP 2000 nonlinear software to obtain capacity curve parameters for representative Indian URM buildings, based on a field survey and statistical analysis. Vulnerability functions are estimated using the obtained capacity curves. Damage Probability Matrices (DPMs) are obtained using the approximate PGA-intensity correlation relationship as per Indian seismic building code and are compared with the commonly used intensity scales and empirical damage data observed after the 2001 Bhuj earthquake.

Incorporating Simulated Ground Motion in Seismic Risk Assessment: Application to the Lower Indian Himalayas

In this study, the effects of implementing stochastic finite fault ground motion simulations in earthquake hazard and risk assessment are evaluated. The investigations are conducted for the city of Dehradun (Indian Himalayas). We compare two ground motion estimation techniques: a ground motion prediction equation–based technique and a simulation-based technique. The comparison focuses on the differences the techniques imply on earthquake damage and loss estimates. Ground motion simulations are first calibrated against the instrumental recordings of the 1991 Mw 6.8 Uttarkashi earthquake. Afterward, a number of events are considered with different magnitude, distance, and azimuth to the source. Results indicate large differences between ground motion and loss estimates derived by the two methods, especially in the direction of rupture propagation, which persist to 2–2.5 fault lengths distance. It is therefore strongly recommended to consider rupture kinematics and orientation to the test bed when providing ground motion estimates for near-field earthquake loss assessment studies.

Seismic Characterization and Vulnerability of Building Stock in Hilly Regions

AbstractBecause of the limitations posed by the topographic conditions, buildings located on hill slopes have highly irregular configurations in comparison with buildings located on flat terrain. E...

Floor Spectra of Inelastic RC Frame Buildings Considering Ground Motion Characteristics

A range of reinforced concrete frame buildings with different levels of inelasticity as well as periods of vibration is analyzed to study the floor response. The derived floor acceleration response spectra are normalized by peak ground acceleration, peak floor acceleration, and ground response spectrum. The normalization with respect to ground response spectrum leads to the lowest coefficients of variation. Based on this observation as well as previous studies, an amplification function is proposed that can be used to develop design floor spectra from the ground motion spectrum, considering the building’s dynamic characteristics and level of inelasticity.

A Next-generation Open-source Tool For Earthquake Loss Estimation

The present research has been benefited from funding of NORSAR and the Univ. Alicante through research contracts (NORSAR1-14A, NORSAR1-08I), the funding of the Ministerio de Economia, Industria y Competitividad (CGL2016-77688-R) and the Generalitat Valenciana (BEST/2012/173 and AICO/2016/098). The development and implementation of the liquefaction risk assessment methodology is done under the LIQUEFACT project funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement (No. 700748).

Earthquake Loss Evaluation (ELE) for the City of Khujand, Sughd Province, Tajikistan

The main scope of the present article is to describe the different technical aspects and steps that were implemented towards a thorough earthquake risk estimation for the city of Khujand, the capital of Tajikistan’s northernmost province, Sughd. The development of the risk model involved both extensive fieldwork and computational work, including: soil amplification studies; defining ground shaking scenarios for earthquakes on local active faults that could cause damage, and for historical earthquakes that have caused damage to the city’s building stock; demarcation of the Khujand city area and its subdivision into geographical units; definition of building typology classes and generating corresponding vulnerability functions; collection of building inventory data as well as socio-economic information, and the computation of damage and loss scenarios. The earthquake risk model for the city of Khujand can be used as guidance for local authorities for future city planning and earthquake mitigation actions by helping to predict earthquake intensity in a given location, and the expected damage and socio-economic losses for any class of building. The procedure and many of the conclusions drawn can be applied in risk studies of other areas in Tajikistan and Central Asia.

Seismic Performance of Shear-Wall and Shear-Wall Core Buildings Designed for Indian Codes

The shear-wall and shear-wall cores are the most commonly used lateral load resisting elements in mid-rise to high-rise RC buildings. The present study focusses on estimation of seismic performance of shear-walls and shear-wall core buildings designed for Indian codes using non-linear pushover analysis. The literature review for modelling of shear-walls is carried out and the most commonly used models, i.e. wide column model and shell element model are validated through the experimental results available in literature. It is observed that both the wide column model and shell element model predict nearly the same strength capacity for the shear-walls and shear-wall cores. However, the wide column model underestimates while the shell element model overestimates the ductility capacity of the shear-walls and shear-wall cores. It is also observed that the stiffness obtained from moment-curvature analysis is in close agreement with the experimental results while the shell element model predicts high initial stiffness and after cracking it reduces and matches with experimental results. These validated models are implemented for performance evaluation of “Dual Systems” designed according to Indian code. It has been observed that buildings with shear-walls placed at periphery have better performance than buildings with centrally placed shear-wall core.