Browsing by Author "Gautam, Dipendra"
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- Common structural and construction deficiencies of Nepalese buildingsPublication . Gautam, Dipendra; Pinheiro Rodrigues, Hugo Filipe; Bhetwal, Krishna Kumar; Neupane, Pramod; Sanada, YashusiThis paper outlines the common observed failure patterns in the buildings of Nepal after MW 7.8 Gorkha (Nepal) earthquake. Several types of damage patterns were observed for reinforced concrete buildings, as well as for unreinforced masonry and adobe houses during the reconnaissance survey performed immediately after the earthquake of 25 April 2015. Several field visits in the affected districts were conducted and associated failure/damage patterns have been identified and analyzed. This paper also covers damage patterns in non-engineered buildings, middle and high-rise buildings, commercial complexes, administrative buildings, schools and other critical facilities from Kathmandu valley as well as other affected districts.The construction and structural deficiencies are identified as the major causes of failure, however local soil amplification, foundation problems, liquefaction associated damages and local settlement related damages are also significantly observed during this earthquake and reported in the present paper. In the end, the lessons learned from the field survey are resumed in order to give some guidelines for future construction practices.
- Generation of spectrum-compatible acceleration time history for NepalPublication . Chaulagain, Hemchandra; Rodrigues, Hugo; Varum, Humberto; Silva, Vitor; Gautam, DipendraThe 25 April 2015 Gorkha earthquake in Nepal caused severe structural damage in central Nepal, including the capital city Kathmandu. Both seismic vulnerability analysis of affected buildings and nonlinear time history analysis need increasing time history. However, no adequate records are available in Nepal, thus structural engineering practices follow Indian guidelines. The Nepal building code allows time history analysis along with the seismic coefficient and response spectrum methods, so nonlinear time history analysis can be used to assure adequate seismic safety. To fulfill the gap of recorded accelerograms, we developed artificial acceleration time histories considering the seismic hazard model of Chaulagain et al. (2015). We compared the synthetic accelerograms developed in this study with the records of Gorkha earthquake; the recorded maximum peak ground acceleration during the Gorkha earthquake showed comparable acquaintance only to the peak amplitudes of synthetic accelerograms generated for 300- and 475-year return periods.
- Performance of Medium-to-High Rise Reinforced Concrete Frame Buildings with Masonry Infill in the 2015 Gorkha, Nepal, EarthquakePublication . Barbosa, Andre R.; Fahnestock, Larry A.; Fick, Damon R.; Gautam, Dipendra; Soti, Rajendra; Wood, Richard; Moaveni, Babak; Stavridis, Andreas; Olsen, Michael J.; Pinheiro Rodrigues, Hugo FilipeFollowing the 25 April 2015 Mw 7.8 Gorkha, Nepal, earthquake and subsequent aftershocks, field surveys were conducted on medium-to-high rise reinforced concrete (RC) frame buildings with masonry infill located in the Kathmandu Valley. Rapid visual assessment, ambient vibration testing, and ground-based lidar (GBL) showed that these buildings suffered damage ranging from light to severe, where damage occurred in both structural and nonstructural elements, but was most prevalent in nonstructural masonry infills. Finite-element structural analyses of selected buildings corroborate field observations of only modest structural damage. The lack of severe structural damage in this relatively limited class of engineered medium-to-high rise RC infill frame buildings illustrates the impact of modern seismic design standards and stands in stark contrast to the severe damage and collapse observed in low-rise nonengineered RC infill frame buildings. Nonetheless, the nonstructural damage hindered many of these buildings from being occupied for many months following the earthquake and subsequent aftershocks.
- Response and rehabilitation of historic monuments after the gorkha earthquakePublication . Weise, Kai; Gautam, Dipendra; Rodrigues, HugoA 7.8 magnitude earthquake struck Nepal on April 25, 2015, followed by numerous aftershocks, devastating hundreds of villages, residential buildings, and historical monuments. The destruction was extensive and the response in respect to cultural heritage needed to be coordinated. This chapter provides an overview of the response to the destruction to Nepal’s cultural heritage and the challenges of rehabilitation. During the past years, the Kathmandu Valley World Heritage Site has been preparing for the earthquake that was to strike Nepal. Clearly, one is never fully prepared. After the initial response phase and with the onslaught of the monsoon rains, rehabilitation planning began. Rehabilitation however cannot focus just on rebuilding the monuments. The tangible is an expression that has over the centuries always been damaged and rebuilt. Sustainability is achieved when the community ensures continuity and the concept of continuity of culture become the basis for reconstruction.
- Revisiting Major Historical Earthquakes in Nepal: Overview of 1833, 1934, 1980, 1988, 2011, and 2015 Seismic EventsPublication . Chaulagain, Hemchandra; Gautam, Dipendra; Rodrigues, HugoDue to its location in the region of interaction between the Indian and Eurasian plates, several earthquakes hit Nepal each year. These shaking events, from weak to strong, characterize Himalayan earthquakes, and major events in the past caused enormous losses in terms of casualties, injuries, biodiversity, and the country’s economy. Due to lack of proper accounts related to the occurrence, damage, and losses of past earthquakes, few accounts of the 20th century earthquakes can be found in existing literature; and comparative analysis of these earthquakes has not been done. To fill this hiatus of detailed accounts and interpretation of notable earthquakes in Nepal, this chapter offers classified damage statistics, losses, and the impact on the socioeconomic setting of the affected areas. In addition, it presents the damage to gender, rural, and urban populations along with brief details of known earthquakes since 19th century.
- Seismic performance of buildings in nepal after the gorkha earthquakePublication . Varum, Humberto; Dumaru, Rakesh; Furtado, André; Barbosa, André R.; Gautam, Dipendra; Rodrigues, HugoFollowing the strong earthquake of Gorkha, Nepal, on April 25, 2015, and a strong aftershock on May 12, a field reconnaissance of structural damage and structural collapses was performed around the affected areas, particularly in the region around the capital Kathmandu. The main goal was to develop detailed descriptions of the seismic performance of the Nepalese building stock. To achieve this goal, the field reconnaissance survey was carried out after the two main seismic events. In this chapter, a summary of the survey is provided, focusing on both recent reinforced concrete (RC) buildings and older substandard constructions. In addition, detailed descriptions of the observed damage to urban masonry building stock and rural vernacular constructions are provided. This chapter presents evidence from the field that justifies the observed seismic performance and enables the depiction of damage modes, which could be insightful regarding future efforts to develop earthquake-resistant constructions and strategies to improve the seismic behavior around the world.
- Seismic vulnerability of urban vernacular buildings in Nepal: case of newari constructionPublication . Gautam, Dipendra; Rodrigues, HugoThis paper analyzes the seismic vulnerability of vernacular Newari buildings in Nepal. Based on the damage statistics and failure modes recorded during 1934, 1988, 2011, and 2015 earthquakes, damage probability matrices and seismic fragility functions are derived in this paper. Notable seismic features of the Newari buildings are identified and reported using forensic approach. The result of this study highlights that the vernacular Newari buildings are highly vulnerable in the case of minor to major earthquakes; however, the seismic features have contributed to downscale the damage extent.