Papers by Hemchandra Chaulagain
RUDN Journal of Medicine
Relevance . Oxygen therapy is commonly used in the emergency and critical cases which is the firs... more Relevance . Oxygen therapy is commonly used in the emergency and critical cases which is the first line treatment in many critical conditions. Oxygen therapy is a medical treatment prescribed mainly for hypoxic patients, which provides oxygen at higher concentrations than that found in atmosphere (21%). Oxygen administering depends on the needs of the patients conditions and in some cases medical treatment. The present study aims to assess the level of awareness on oxygen therapy among nurses and examine the association between level of knowledge, attitude and selected socio-demographic variables. Materials and Methods . A quantitative descriptive cross-sectional study design was used. A non-probability purposive sampling technique was used to select 125 samples. The data were collected for 6 weeks using a semi-structured self-administered questionnaire. Descriptive statistics (frequency, percentage, mean, standard deviation) was used for quantitative data analysis and inferential s...
Impacts and Insights of Gorkha Earthquake in Nepal
Asian Journal of Civil Engineering
Advances in Civil Engineering
Asian Journal of Civil Engineering
Journal of Building Engineering
Comptes Rendus Geoscience
Earthquakes and Structures, 2015
The main objective of this study is to analytically investigate the effectiveness of different st... more The main objective of this study is to analytically investigate the effectiveness of different strengthening solutions in upgrading the seismic performance of existing reinforced concrete (RC) buildings in Nepal. For this, four building models with different structural configurations and detailing were considered. Three possible rehabilitation solutions were studied, namely: (a) RC shear wall, (b) steel bracing, and (c) RC jacketing for all of the studied buildings. A numerical analysis was conducted with adaptive pushover and dynamic time history analysis. Seismic performance enhancement of the studied buildings was evaluated in terms of demand capacity ratio of the RC elements, capacity curve, inter-storey drift, energy dissipation capacity and moment curvature demand of the structures. Finally, the seismic safety assessment was performed based on standard drift limits, showing that retrofitting solutions significantly improved the seismic performance of existing buildings in Nepal.
Structural Engineering and Mechanics, 2015
RC buildings constitute the prevailing type of construction in earthquake-prone region like Kathm... more RC buildings constitute the prevailing type of construction in earthquake-prone region like Kathmandu Valley. Most of these building constructions were based on conventional methods. In this context, the present paper studied the seismic behaviour of existing RC buildings in Kathmandu Valley. For this, four representative building structures with different design and construction, namely a building: (a) representing the non-engineered construction (RC1 and RC2) and (b) engineered construction (RC3 and RC4) has been selected for analysis. The dynamic properties of the case study building models are analyzed and the corresponding interaction with seismic action is studied by means of non-linear analyses. The structural response measures such as capacity curve, inter-storey drift and the effect of geometric nonlinearities are evaluated for the two orthogonal directions. The effect of plan and vertical irregularity on the performance of the structures was studied by comparing the results of two engineered buildings. This was achieved through non-linear dynamic analysis with a synthetic earthquake subjected to X, Y and 45° loading directions. The nature of the capacity curve represents the strong impact of the P-delta effect, leading to a reduction of the global lateral stiffness and reducing the strength of the structure. The non-engineered structures experience inter-storey drift demands higher than the engineered building models. Moreover, these buildings have very low lateral resistant, lesser the stiffness and limited ductility. Finally, a seismic safety assessment is performed based on the proposed drift limits. Result indicates that most of the existing buildings in Nepal exhibit inadequate seismic performance.
Engineering Failure Analysis, 2016
Gorkha earthquake (MW 7.8) occurred in Nepal on 25 April 2015 at 11:56 local time. This earthquak... more Gorkha earthquake (MW 7.8) occurred in Nepal on 25 April 2015 at 11:56 local time. This earthquake is the most devastating event after the 1934 great Bihar-Nepal earthquake (MW 8.1) in terms of damages. In that earthquake, 498,852 buildings were completely collapsed and other 256,697 were partially damaged. Structural and non-structural damages were occurred in all types of prevalent structural systems in affected areas. This paper outlines the structural performance during Turkey, Bhuj, Kashmir, Haiti, Chile and L'Aquila earthquakes from past two decades worldwide and comparisons are made in terms of structural forms, regulations to infer the lessons to be learnt by Nepal in the aftermath of Gorkha earthquake. Apart from this, review of structural performance during two major earthquakes of 1934 (MW 8.1) and 1988 (MW 6.5) in Nepal is presented to draw insights in terms of changing structural forms, technology and housing units. Insights are presented in terms of codal provisions and distribution of structures in Nepal. With due account of major world earthquake paradigms and historical earthquakes from Nepal and detailed field reconnaissance after the Gorkha earthquake, interpretations are disseminated in terms of lessons to be learned by Nepal in the aftermath of Gorkha earthquake. Comparative analyses have highlighted the urgent need of building code revision and development of proper strengthening techniques for the affected structures.
Earthquake Engineering and Engineering Vibration, 2016
Reinforced concrete (RC) buildings in Nepal are constructed with RC frames and masonry infi ll pa... more Reinforced concrete (RC) buildings in Nepal are constructed with RC frames and masonry infi ll panels. These structures exhibit a highly non-linear inelastic behavior resulting from the interaction between the panels and frames. This paper presents an extensive case study of existing RC buildings in Nepal. Non-linear analyses were performed on structural models of the buildings considered as a bare frame and with masonry infi ll, in order to evaluate the infl uence of infi ll walls on the failure mechanisms. Five three-storey buildings with different structural confi gurations and detailing were selected. The effect of masonry infi ll panels on structural response was delineated by comparing the bare-framed response with the infi ll response. Seismic performance is evaluated with regard to global strength, stiffness, energy dissipation, inter-storey drift, and total defl ection of the structure. A parametric analysis of structures with masonry infi ll is also performed. For this, the infl uence of different material properties is studied, namely diagonal compressive stress, modulus of elasticity and tensile stress of masonry infi ll panels. Study results show that masonry infi ll increases the global strength and stiffness of the structures; it decreases the inter-storey drift and hence the total displacement of the structure. The results quantify the infl uence of the infi ll panels on structural response and, in particular, the effect of the diagonal compressive strength of the masonry wall.
Bulletin of Earthquake Engineering, 2015
The capital city, Kathmandu, is the most developed and populated place in Nepal. The majority of ... more The capital city, Kathmandu, is the most developed and populated place in Nepal. The majority of the administrative offices, headquarters, numerous historical monuments, and eight World Heritages sites are in the Kathmandu Valley. However, this region is geologically located on lacustrine sediment basin, characterized by a long history of destructive earthquakes. The past events resulted in great damage of structures, losses of human life's and property, and interrupted the social development. Therefore, earthquake disaster management is one of the most serious issues in highly seismically active regions such as the Kathmandu Valley. In recent years, the earthquake risk in this area has significantly increased due to uncontrolled development, poor construction practices with no earthquake safety consideration, and lack of awareness amongst the general public and government authorities. In this context, this study explores the realistic situation of earthquake losses due to future earthquakes in Kathmandu Valley. To this end, three municipalities: (a) Kathmandu metropolitan city (KMC), (b) Lalitpur Sub-Metropolitan City (LSMC) and (c) Bhaktapur Municipality (BMC) are selected for study. The earthquake loss estimation in the selected municipalities is performed through the combination of seismic hazard, structural vulnerability, and exposure data. For what concerns the seismic input, various earthquake scenarios considering four seismic sources in Nepal were adopted. Regarding the exposure, data about the type of existing buildings, population, and ward level distribution of building typologies is estimated from the recent national census survey of 2011. The economic losses due to the scenario earthquakes are determined using fragility functions. The commonly used standard fragility curves are adopted for adobe, brick/stone with mud mortar buildings, and brick/stone with cement mortar buildings. For the reinforced concrete structures, a new fragility model was derived considering four construction typologies: i) current construction practices (CCP), ii) structures according to the Nepal buildings code (NBC), iii) structures according to the modified Nepal building code (NBC+) and iv) well designed structures (WDS). In this study, a set of fragility functions is converted into a vulnerability model through a consequences model. Finally, the ward level distribution of damage for each building typology, building losses and the corresponding economic loss for each scenario earthquake is obtained using the OpenQuake-engine. The distribution of damage within the Kathmandu Valley is currently being employing in the development of a shelter model for the region, involving various local authorities and decision makers.
Reinforced concrete (RC) buildings in Nepal are constructed as RC frames with masonry infill pane... more Reinforced concrete (RC) buildings in Nepal are constructed as RC frames with masonry infill panels. These structures exhibit a highly non-linear inelastic behaviour resulting from the interaction between the masonry infill panels and the surrounding frames. In this context, the paper presents an extensive case study of existing RC-framed buildings in a high seismic risk area in Nepal. A sensitivity analysis of the structures with masonry infill is performed. For this, the influence of different material properties is studied, namely diagonal compressive stress, modulus of elasticity and tensile stress of masonry infill panels. Result shows the influence on the structural behaviour particularly by variation of the diagonal compressive strength of infill masonry panels.
Earthquake Spectra, 2010
A reliable building vulnerability assessment is required for developing a risk-based assessment a... more A reliable building vulnerability assessment is required for developing a risk-based assessment and retrofit prioritization. Tesfamariam and Saatcioglu (2008) proposed a simple building vulnerability module where the building performance modifiers are in congruence with FEMA 154. This paper is an extension of the building vulnerability assessment that include detailed performance modifier in congruence with FEMA 310 that is represented in a heuristic based hierarchical structure. Some of the input parameters are obtained through a walk down survey and are subject to vagueness uncertainty that is modelled through fuzzy set theory. A knowledge base fuzzy rule base modeling is developed and illustrated for reinforced concrete buildings damaged in the 1 May 2003 Bingöl, Turkey earthquake.
Australian Journal of Structural Engineering
Cinpar 2013 (Conference paper), Jun 5, 2013
The effectiveness of reinforced concrete (RC) column jacketing for improving the seismic performa... more The effectiveness of reinforced concrete (RC) column jacketing for improving the seismic performance of existing RC building structures were studied. Four three storey buildings with different structural configuration and detailing were selected for seismic assessment and retrofitting purpose. The response of structures (original and retrofitted) was evaluated in terms of capacity curve and inter-storey drift. The case studies also intend to verify the effect of P-delta effects and bi-axial response of columns under non-linear time history analysis. The nature of the capacity curve represents the strong impact of the P-delta effect, leading to a reduction of the global lateral stiffness and reducing the strength of the structure. Finally, a seismic safety assessment is performed based on the drift limit proposed by FEMA-356. The assessment of original building structures indicates that they may exhibit inadequate seismic performance. However, RC column jacketing highly improves seismic performance of all the structures and results maximum drift demand within the drift limit proposed by FEMA-356.
IRF' 2013 (Conference paper), Jun 27, 2013
This paper evaluates the seismic performance of existing three-storey residential reinforced conc... more This paper evaluates the seismic performance of existing three-storey residential reinforced concrete (RC) buildings in Nepal. For this, it was designed a representative RC building structure (WDS) and the results were compared with similar buildings detailed with: i) Current Construction Practices (CCP); ii) Nepal Building Code (NBC) and iii) Modified Nepal Building Code (NBC+) recommendations. The results were analyzed and compared in terms of capacity curve, inter-storey drift and detailing of structures. The overall comparison indicates that CCP structure has a low amount of reinforcement both in beam and column sections when compared with the WDS structure. For the structure designed according with the NBC and NBC+ recommendations, improvements are clear relatively to the CCP structure, but it may be not sufficient for the demands in regions with high seismic hazard. Non-linear analysis shows that CCP and NBC structures experiences lower base shear capacity with higher inter-storey drift demand than other structures. Finally, the influence of seismic zone factor on reinforcement demand of the structure is analysed by designing the same WDS structure for a low, medium and high seismic hazard zone.
Advances in Structural Engineering (Accepted), May 21, 2014
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Papers by Hemchandra Chaulagain