Resource Accessibility and Vulnerability in Andhra Pradesh: Caste and Non‐Caste Influences

Coastal Andhra Pradesh in southern India is prone to tropical cyclones. Access to key resources can reduce the vulnerability of the local population to both large‐scale disasters, such as cyclones, and to the sort of small‐scale crises that affect their everyday lives. This article uses primary fieldwork to present a resource accessibility vulnerability index for over 300 respondents. The index indicates that caste is the key factor in determining who has assets, who can access public facilities, who has political connections and who has supportive social networks. The ‘lower’ castes (which tend to be the poorest) are marginalized to the extent that they lack access to assets, public facilities and opportunities to improve their plight. However, the research also indicates that the poor and powerless lower castes are able to utilize informal social networks to bolster their resilience, typically by women's participation with CBOs and NGOs. Nevertheless it is doubtful whether this extra social capital counterbalances the overall results which show that — despite decades of counteractions by government — caste remains a dominant variable affecting the vulnerability of the people of coastal Andhra Pradesh to the hazards that they face.     

Analytical Fragility Curves for a Class of Horizontally Curved Box-Girder Bridges

Analytical fragility curves were developed for curved single-frame concrete box-girder bridges with seat-type abutments. The bridges incorporated the current seismic design considerations and modern details that were recently adopted by CALTRANS. Fragility curves demonstrated that columns were the most vulnerable components, while the modern seismic details successfully protected the abutment piles from damage during large earthquakes. Increasing the subtended angle affected the seismic vulnerability at both the component and system levels. Functional relationships were proposed to evaluate the seismic vulnerability of curved bridges. Moreover, fragility curve parameters were shown to depend on soil condition and spectral characteristics of ground motions.     

Synthesizing Broadband Time-Histories at Near Source Sites; Case Study, 2003 Bam Mw6.5 Earthquake

The main objective of this article is to synthesize the 2003 Bam earthquake. A hybrid method is proposed for synthesizing the near-fault broadband timehistories; a theoretical green's function method and a stochastic finite-fault approach for generating time histories at low and high frequencies, respectively. A genetic algorithm is developed to optimize the differences between synthesized and recorded ground motions.

The proposed technique can be used for dynamic nonlinear analysis of structures and site specific hazard analysis of the regions with lack of sufficient data and also for retrofitting the damaged structures during Bam earthquake, particularly the well-known adobe buildings of Arg-e-Bam.     

Seismic Hazard Analysis Using Discrete Faults in Northwestern Pakistan: Part II – Results of Seismic Hazard Analysis

This article is the second of two companion articles that evaluate seismic hazard in northwestern (NW) Pakistan. Using the properties and characteristics of discrete faults in NW Pakistan described in the first article, probabilistic and deterministic seismic hazard analyses for 11 major cities in NW Pakistan were conducted. The results from both probabilistic and deterministic seismic hazard analyses exhibit good agreement. Median deterministic spectra compare favorably with uniform hazard spectra (UHS) for 475- or 975-year return periods, while the 84^th-percentile deterministic spectra compare favorably with the UHS for a 2475-year return period. Peak ground accelerations (PGAs) for 2475-year return periods exceed 1.0 g for the cities of Kaghan and Muzaffarabad, which are surrounded by major faults. The PGAs for a 475-year return period for these cities are approximately 0.6g — 3 to 4 times greater than estimates by previous studies using diffuse areal source zones. The PGAs for some cities located farther from faults (including Astor, Malakand, Mangla, Peshawar, and Talagang) are similar to those predicted using diffuse areal source zones. Seismic hazard maps for PGA and spectral accelerations at periods of 0.2 s and 1.0 s corresponding to three return period (2475, 975, and 475 years) were produced. Based on deaggregation results, a discussion of the conditional mean spectra for engineering applications is presented.     

Analytical Modeling of Horizontally Curved Steel Girder Highway Bridges for Seismic Analysis

This article introduces a generic modeling approach that is suitable for static and dynamic analysis, and response assessment of highway bridges with varying levels of irregularities. The proposed approach and modeling recommendations are based on grillage modeling rules that allows explicit representation of various types of details and components. The validity and accuracy of the proposed approach is demonstrated against three-dimensional finite element models as well as experimentally recorded response various benchmark bridges. While achieving remarkable accuracy, the required analysis time was also reduced up to 80%, making the proposed approach suitable for computationally intensive studies.