The Journal of Science and Engineering (JScE) is a refereed journal to serve the interests of Professionals, academics and research organizations working in the field of science and engineering. It is published by the Khwopa Engineering College and Khwopa College of Engineering, Bhaktapur, Nepal
Khwopa Engineering College & Khwopa College of Engineering
Local Building Cultures in Reconstruction
The National Reconstruction Authority (NRA) reported 93% completion of private house reconstruction after Nepal’s 2015 earthquake, but this achievement largely ignored local building cultures and community needs. Uniform enforcement of building codes and “Build Back Better” guidelines led to standardized concrete “grant houses” that often failed to reflect climate adaptation, livelihoods, social organization, economic capacity, or cultural practices. Many households view these houses as temporary and are modifying them informally, often without technical support. With the end of NRA, ongoing reconstruction relies heavily on untrained masons and informal practices, increasing vulnerability. The 2023 Jajarkot earthquake exposed persistent construction flaws, limited code compliance, and weak dissemination of earthquake-resistant knowledge. Traditional stone-and-mud housing was mistakenly blamed for failures, accelerating inappropriate adoption of industrial materials. Poor land-use governance and unresolved land ownership further compounded risks. Drawing on a decade of experience, ASF Nepal highlights lessons from community-based, socio-technical reconstruction programs that integrate local knowledge, skills, and livelihoods to achieve safer, culturally rooted, and sustainable housing outcomes.
Assessing Seismic Response in Dual Tower Connected Structures at Different Storey Levels Through Fixed and Flexible Connections
Skybridges are horizontal connectors between towers, influencing structural dynamics by enhancing coupling and altering dynamic load responses. This study examines seismic performance of dual eight storey tower buildings interconnected by 8 m x 14 m skybridges at three levels (first and second, third and fourth, and seventh and eighth floors). The passive isolations systems using Lead Rubber Bearings (LRB) and High Damping Rubber Bearings (HDRB) are compared with conventional rigid connections. Nonlinear time history analyses are conducted in ETABs v20.1 using matched spectral records of the New Zealand-2021 and Loma Prieta-1989 earthquakes, based on Nepal’s building code NBC 105:2020 design response spectrum (475-year return period), and unscaled Gorkha-2015 earthquake. Parameters such as base shear, isolator displacement, structure displacement, drift, and hysteresis energy are analyzed. Results show a 46% base shear reduction with isolated skybridges. Lower floor isolation effectively minimizes top story displacements and inter storey drifts due to improved decoupling. Upper floor isolation leads to larger isolator displacements. LRB exhibit 14% higher energy dissipation than HDRBs. Maximum utilization of HDRB occurs under high displacements within the permissible design limits. For the cyclic load and rapid force reversal, HDRB shows stable force-displacement behavior and reduced cumulative damage.
Load Resisting Behavior of Nepalese Rest-house
Traditional Nepalese rest houses, locally known as patis or sattals, are vernacular structures that have served as communal shelters and social spaces for centuries which can also be used during the earthquake. These buildings typically exhibit a hybrid structural system, with timber frames along one grid and masonry load-bearing walls along another, constructed using regionally available materials and indigenous craftsmanship. This configuration often leads to eccentricity in both mass and stiffness, significantly influencing the building’s global seismic response and torsional behavior. This study investigates the load-resisting behavior of a typical Nepalese rest house, with particular emphasis on the traditional Nepali timber joints. A representative structural model was developed based on field documentation and literature, capturing key geometric and material characteristics. Numerical analysis was conducted to evaluate the structural response under gravity and lateral loads, simulating seismic actions. Special focus was given to the behavior of traditional timber joints, which are commonly constructed without nails or adhesives, relying instead on intricate interlocking geometries. A macro-modeling approach was adopted for masonry walls, while timber joints were studied at both macro and micro levels using the finite element method along with interaction properties. The results provide insights into the interaction between timber framing and masonry walls, highlighting the strengths and vulnerabilities of this traditional construction system. The findings contribute to the understanding of Nepalese vernacular architecture and offer a basis for its preservation, retrofitting, and informed adaptation in contemporary practice.
Seismic Qualification: An Approach for Safe Power System During Earthquakes
Earthquakes have caused many catastrophes in the past. Construction industries, electrical industries and people should be aware of the danger and prepared against earthquakes by constructing earthquake resistant structures. Past earthquake data reveals electrical and telecommunication facilities are seismically vulnerable and susceptible to failure due to seismic dynamic loading. High voltage substation equipments are most vulnerable in electrical and telecommunication facilities. Demand for electric power supply during post-earthquake and safety of consumers emphasize the need for seismic reliable electrical power system. For reliable power supply during and after earthquakes electrical equipment shall be seismically qualified before installation. Basics of seismic qualification of electrical equipment, procedure of qualification and relevant codal provisions are presented in this paper.
Assessment of Soil-Structure Resonance Probability of Educational Buildings in Kageshwori Municipality
This study focuses on assessing the possibility of soil–structure resonance in school buildings located within Kageshwori Manohara Municipality, Nepal, by comparing the natural time periods of the ground and the structures. Ambient vibration measurements were carried out using geophones to determine the predominant period of both the selected school buildings and the nearby free-field sites. The Nakamura Horizontal-to-Vertical Spectral Ratio (HVSR) technique was applied to ambient noise data to identify the predominant soil period, which was found to range between 1.14 and 3.23 seconds, reflecting the local ground response characteristics. Similarly, the natural periods of the buildings, obtained through the Floor Spectral Ratio (FSR) or Horizontal-to-Horizontal (H/H) method, ranged from 0.11 to 0.37 seconds. Since the soil and building periods do not coincide, the likelihood of resonance occurring in these school structures is quite low. However, the seismic vulnerability index values of the ground beneath the studied buildings fall between 44.96 and 282.61 (classified as Very High), suggesting that the area is composed of relatively soft ground with thin sediment layers. Furthermore, the results show that buildings tend to be more vulnerable in the east–west (EW) direction than in the north–south (NS) direction, highlighting the need for targeted retrofitting measures. Overall, this study provides important insights for engineers and decision-makers aiming to enhance the seismic resilience of educational buildings in this earthquake-prone municipality.
Design and Calibration of a MEMS Seismic Monitoring System
We designed a seismic monitoring system integrating Micro Electro-Mechanical Systems (MEMS) accelerometer sensors with a Raspberry Pi and Long-Range (LoRa) communication technology. The system aims to provide a cost-effective and flexible approach for studying ground motion at various locations, with applications in geological research and disaster preparedness. Two types of MEMS sensors were employed to measure ground acceleration in three components. The Raspberry Pi functions as the central processing unit, responsible for data acquisition, processing, and storage. The data is saved in ASCII format and transmitted wirelessly to the main monitoring station using LoRa modules. Calibration of the system is carried out on a 1D shake table to ensure measurement accuracy. Further performance validation is conducted by comparing the sensor outputs with a standard strong-motion seismometer (Mitsutoyo JEP-6A3-2) in both the time and frequency domains. Experimental results from ambient vibration measurements indicate that the MPU6050 sensor achieves a higher goodness of fit with the strong-motion seismometer as compared to the ADXL345. This highlights the importance of filtering and calibration in improving measurement precision. Despite the limitations, the proposed system offers a scalable and cost-effective solution for seismic data collection of seismic monitoring system.
Economic Impact of Restoration of Historic Pond in Bhaktapur - A Case Study of Bhaju Pukhu
Bhaktapur, a city with several UNESCO World heritage sites, is known for its rich cultural legacy, traditional architecture and water management system, which include multiple medieval ponds. These historical ponds, which were originally essential to the city’s ancient water system and cultural life has been neglected, polluted and encroached upon for decades. Recent restoration projects seek to restore its historical relevance, enhance community well-being, and contribute to sustainable urban development. This study focuses on urban implications of culturally significant pond in Bhaktapur, with particular emphasis on Bhaju Pukhu to better understand the economic impact of such projects. The restoration of historical ponds not only preserves cultural heritage but also provides tangible economic benefits to the neighbourhood. This case study explores the financial implications of restoring Bhaju Pukhu, a centuries-old pond in Bhaktapur, Nepal. The study finds that the project has made a considerable contribution to the local economy through field surveys, interviews with local stakeholders, and analysis of tourism and business activity before and after restoration. Key findings include increased number of visitors, growth in local business such as tea shops, fast food, local vendors, and higher property values in the surrounding area. Furthermore, the restored pond has become a place for cultural events and festivals, resulting in increased economic activity. Employment opportunities were created during and after the restoration process. The study indicates that heritage pond restoration, when carefully planned and supported by the community, can serve as a driver for long-term economic development in historic cities such as Bhaktapur.
Reconstruction of Thanthu Durbar, Bhaktapur: A Case Study
Thanthu Durbar in Bhaktapur Durbar Square Complex is believed to have been a part of the historic Thanthu Durbar, which means "Upper Palace" in Nepal Bhasha, indicating its position on higher ground relative to the main palace complex. Historically, it served as the Safaai Addha (Cleaning Department) in 2004 B.S. and was later repurposed as the municipal office of Bhaktapur Municipality. Bhaktapur Municipality has undertaken the reconstruction of historic Rana style building dating back to the Malla period. This paper presents a research project focused on employing archaeological and architectural studies through indigenous construction techniques. The methodology involved comprehensive site surveys, documentation, archaeological excavation, and consultations with conservation architects, historians, and archaeologists. This paper highlights the ongoing reconstruction process of building in architectural style of the Malla period in accordance with the research and excavation study results and its adherence to traditional construction techniques. The reconstruction of the building serves as a significant step towards safeguarding Nepal's architectural heritage and promoting sustainable approaches to heritage preservation. The reconstruction project aims to reconstruct the durbar to its Malla period design regarding archaeological research and structurally safeguarding the building. The findings from this research project contribute to the broader understanding of heritage reconstruction practices in Nepal and provide insights into the preservation of cultural heritage in seismic-prone regions. The reconstruction of the durbar of heritage site serves as a significant step towards safeguarding Nepal's architectural heritage and promoting sustainable approaches to heritage preservation.
Out-of-Plane Dynamic Shock Table Testing of a Mock-Up Unreinforced Stone Masonry Building
This paper describes the results of a dynamic shock table test of an unreinforced stone masonry mock-up building. The primary objective was to study the dynamic characteristics and collapse mechanism of the walls in the out-of-plane direction. The test setup utilized a 3.6m x 6.0m shock table and a two-sided unreinforced stone masonry building mock-up with a slate roof. The walls were constructed of 0.45-m-thick, unreinforced stone masonry with mud mortar, and the roof comprised timber beams, bamboo planks and strips, mud filling, and slate shingles. The shock table test set-up uses a 2070 kg pendulum to impart dynamic shock loads to the table. The roof and walls were connected to ensure they moved together and collapsed with a single shock. The loading protocol involved seven shocks, ranging from 5 to 33 degrees of pendulum swing, and was designed to build damage gradually and culminate in full collapse. Data was collected through video recordings and six accelerometers. While the first three shocks produced minimal damage to the building despite modest accelerations, by the end of the sixth shock, both walls exhibited large vertical cracks. The last shock caused complete collapse of the building and imparted accelerations exceeding 5g to the table and 1.01g to the wall. The test results describe the dynamic characteristics of the walls, damage progression in the walls and the observed damage during a building collapse. This experiment shows that while a single horizontal shock differs from continuous ground shaking experienced in an actual earthquake the results of dynamic shock table tests are a valuable tool in understanding the seismic behaviour of unreinforced stone masonry building.
Investigating The Protective Capabilities of Earthquake Desks Through Compression and Shock Table Tests
This paper describes a series of physical tests conducted on Earthquake (EQ) Desks manufactured in Nepal to determine their capacity and improve the understanding of their performance under falling debris during a seismic event. The testing program included five vertical compression (static) tests and a dynamic shock table test. The desks tested included both secondary (high) school and primary (elementary) school sizes, with some featuring new plywood panel "side protection" to evaluate its effectiveness. The compression tests were aimed to quantify the vertical load and displacement capacities of the desks, as well as their energy absorption capabilities. Results indicated that the desk capacity is highly dependent on the loading application, with a minimum elastic load capacity of 45.7 kN, a minimum peak load capacity of 98.2 kN, a minimum peak displacement capacity of 92 mm, a minimum elastic energy capacity of 0.28 kJ, and a minimum total energy capacity of 7.05 kJ. During the dynamic shock table test, six EQ Desks were subjected to the complete collapse of a full- scale mock-up school classroom. The single-story mock-up building was constructed with two unreinforced stone masonry walls with mud mortar and slate stone roof. The other two sides of the structure were left open. Observations revealed that EQ Desks experienced impacts from stone walls and roofs separately. A significant finding was that although the lateral debris wave pushed some desks, none toppled. EQ Desks with side protection demonstrated a reduction in debris entering the "safety- zone" below the desk. Importantly, all EQ Desks sustained only minor cosmetic damage to the plywood desktop and edging, successfully maintaining their full "safety-zone" throughout the tests, and no simulated occupants (water containers) were punctured, indicating non-lethal injury to children. The vertical demands observed during the shock table test were found to be below the minimum elastic load and energy capacities of the desks. These findings confirm the robust performance of Nepal-built EQ Desks, supporting their appropriateness as a protective solution in single-story stone masonry buildings and potentially two-story structures.
Seismic Floor Response Characteristics of Sloped Roof in Traditional Masonry Structural System Due To Strong Bi-Directional Ground Motions
The recent failure of the sloped roof of the ancient pagoda, Fengyang Drum Tower in eastern China, has raised major concerns about the safety of such a structure. The primary objective of this study is to investigate the engineering demand parameter of a sloping roof in a traditional pagoda masonry structure. Generally, most traditional masonry structures consist of steep, sloping roofs with an angle ranging from 25 to 30 degrees. These roofs carry a large amount of self-weight as well as are supported by the wooden roofing system. These roof systems are critical in terms of public safety during the earthquake evacuation process. They are highly vulnerable to damage due to their location and experience maximum acceleration during earthquakes. The damage on sloped roofs is a critical hazard scenario for a traditionally dense city like Bhaktapur. This study selects a typical pagoda masonry structure for simulating the seismic response of such structures and locates the critical local and global locations of importance. The numerical model is developed utilizing three-dimensional nonlinear shell elements in SAP2000. This study utilizes 10 strong bi-directional natural ground motions for the time history analyses. The global and local structural response due to input strong bi-directional ground motion is investigated. The uni-directional and bi-directional responses are compared to investigate the effect of bi-directional ground motions on response characteristics. Additionally, this study investigates the global response trajectory of the system due to bi-directional ground motion for the precise seismic response characterization. The critical angle of incidence of the traditional pagoda structures is also investigated. This study points out the importance of considering bi-directional ground motions for efficient seismic performance evaluation of such structures. This study recommends updating design code and provisions to address the bi-directional effect of ground motions during structural analysis and seismic performance evaluations of existing structures.
Innovative Retaining wall System for Enhanced Safety and Economy
A retaining wall is a structure designed to resist the lateral pressure exerted by soil, water, or both, especially where elevated soil needs support above stable ground. For low heights, gravity retaining walls are commonly used, relying on their own weight for stability. However, as wall height increases, gravity walls become uneconomical due to the large size and volume of materials required. For medium heights, cantilever retaining walls—typically L- or inverted T-shaped—offer better material efficiency, with thinner stems supported by a base slab. Yet, they become risky for higher walls, as minor foundation defects or scouring at the toe can lead to structural failure and an uneconomical design. In such cases, counterfort retaining walls are preferred. These walls use vertical supports (counterforts) placed at regular intervals on the soil-facing side to reduce bending moments and increase stability. Though effective for tall walls, counterfort designs are complex, labor-intensive, and require skilled workmanship. This paper presents a new type of retaining wall that has been developed by combining the principles of both gravity and cantilever designs. It consists of parallel double walls connected by tie members, spaced vertically at regular intervals. Three-dimensional analysis shows a significant reduction in stress, making this design more economical and safer. Additionally, it does not require skilled labor and allows for faster construction than counterfort walls.
Advancing Seismic wave Simulation: The Application of the Spectral Element Method in Different Geological Settings
Accurately simulating seismic wave propagation remains one of the core challenges in computational seismology, largely driven by the need to represent complex geological structures with high fidelity. Although traditional approaches such as the Finite Difference Method (FDM) and Finite Element Method (FEM) have long served as the backbone of seismic modelling, they struggle to efficiently capture realistic geological geometries and deliver high numerical accuracy. This review examines the pivotal role of the Spectral Element Method (SEM) in overcoming these constraints. By merging the geometric flexibility of FEM with the exponential accuracy of spectral techniques, SEM provides a powerful framework for high-fidelity seismic modelling. We detail the methodological strengths of SEM and systematically evaluate its transformative applications across a spectrum of geometrical settings, from intricate sedimentary basins like Kathmandu to continental-scale models of the Indian Peninsula, concluding with an analysis of future trajectories in the exascale computing era.
Reconstruction Case Studies in Japan and Nepal–Perspectives from Endogenous Development and the ‘Icicle Model’
This study argues about the theory of endogenous development, a theory of social change proposed by Japanese sociologist Kazuko Tsurumi, and its 'icicle model' described by Kunio Yanagita, which complements one of the perspectives on the concept of development that Tsurumi refers to, for the purpose to analyze examples of how adjustment efforts are made between traditional and modern way of life. While traditional life is forced to change due to modern social changes in each society, the differences between the two coexist despite their conflicts. In contrast to the idea of 'exogenous development' that imitates the Western European development model, endogenous development refers to the renewal of traditions through endogenous process in each society in response to changing needs based on the conditions of each society and its natural environment. Among them, the 'icicle model' provides a structural view point of development in which new things created in response to the needs of the new era are layered on top of the icicle, leaving the old inside, so that the new and the earlier values coexist at the same icicle. This study firstly analyzes examples of the 'icicle model' of Japan. Focusing a case of Otsuchi town in Iwate Prefecture, a town that was devastated by the tsunami in the Great East Japan Earthquake (2011), and where the spring water and its wells that were characteristic of the region were incorporated into the reconstruction plan and rebuilt as the town's distinctive, traditional and natural features. This thesis will then look at Nepal's case, a country in same Asian region, focusing on cases of Dhungedhara and Pokhari, both famous traditional water facilities, the existence of which is endangered due to rapid population growth and modern infrastructure needs. An appropriate way to resolve such an issue could be a concept that might be Nepal's 'icicle model'. By examining the cases of these two countries, this study tries to convey the view of endogenous development theory proposed by a Japanese scholar who witnessed rapid changes since the 19th century, and share it in Nepali context which is also witnessing rapid change in the past decades.
Relocation of Monuments in Kwelachhi of Lubhu
Lubhu, a historically important city located in the Lalitpur district, houses numerous monuments from different historical timeline. Lubhu is home to several centuries’ old monuments where some monuments still are intact today though facing many changes due to natural calamities like earthquake while some has undergone changes with the changing urban development factors such as infrastructure expansion especially the road widening projects. Few of such examples are located in the Kwelachhi tole of Lubhu. In 2022, the temples dedicated to Ganesh and a chaitya has been relocated few distance apart to clear the roadways considering the future road expansion in the area. This study focuses on these two temples of the roadside which were shifted to short distances from the original position. The study will focus on the process of relocation of these temples and the issues arouse among the locals. The role of community involvement is important in such conservation programs as they are the users of those monuments in their daily social life. This research will study the engagement of the community in different phases of conservation. The methodologies to conduct this research will be questionnaire surveys, interviews, study of the old photographs, and site inspections. The data will be qualitatively and quantitatively analysed on conservation efforts applied on those structures by the concerned authorities.
Digital Heritage Documentation: Integrating Photogrammetry, Gaussian Splatting, And 3D Mesh Modeling Practices for Enhanced Detail and Efficiency
Nepal's rich architectural heritage is under increasing threat from environmental changes and rapid modernization, highlighting the urgent need for advanced digital preservation methods. Digital architectural and cultural heritage documentation has been evolving, yet the current practices remain limited to their ability to capture detailed structural representation and material nuances combined with its ability to scale and easily deploy. This study explores a hybrid approach that integrates photogrammetry, Gaussian splatting and contemporary 3D mesh modelling workflows to enhance visual fidelity and precise digital replicas. Photogrammetry is recognized for its geometric accuracy but can be computationally demanding and struggle to capture reflective and transparent surfaces. While Gaussian splatting offers fast and high- fidelity visualizations but it's integration with existing modelling pipelines is ongoing. By combining these methods, this study suggests a flexible and potentially more scalable workflow that leverages strength of each technique. Preliminary applications to small monuments indicate improvement in visual fidelity and processing efficiency that captures nuanced material details. Since this workflow requires only photos, it presents a low-barrier option for broader application. For the case study of this workflow, a set number of Nepalese architectural heritage and monuments will be photographed, processed and compared with existing workflows in terms of its visual fidelity \& computational demand.
Course Correcting Power of Surveillance and Social Activism in the Heritage Restoration Process: A Case Study of Rani Pokhari, Kathmandu Metropolitan City
Disasters trigger citizens’ emotions to protect lives and safeguard cultural assets. Citizens often move rapidly to support their neighbors and pay close attention to how their communities are rebuilt and how heritage is restored. This research uses content analysis to demonstrate how community surveillance and social activism play key roles in preventing heritage restoration agencies from going off track and compromising heritage values. It presents the Ranipokhari (Queen’s Pond) post-earthquake restoration case from Kathmandu Metropolitan City (KMC) to answer the research question. The findings reveal that surveillance, in concert with social activism, exposed mistakes and negligence by the pond restoration agencies, brought them back on track, and corrected temple restoration errors committed in the past.
Application of M-Factor in Seismic Assessment of An Existing MRT Building as per NBC 105:2020 and ASCE 41-17
This study presents a comparative evaluation of seismic performance assessment methodologies for a Reinforced Concrete (RC) moment-resisting frame building originally designed using Mandatory Rules of Thumb (MRT) as per NBC 205:1994. The building is re-evaluated under the current prescriptive design framework of NBC 105:2020 and the advanced Performance-Based Design (PBD) methodology specified in ASCE 41-17, with particular emphasis on the role of the modification factor (m-factor) in seismic capacity evaluation. The objective is to examine the applicability, limitations, and effectiveness of conventional code-based design versus modern performance-oriented approaches in the context of existing buildings in seismically active regions. ASCE 41-17 provides a comprehensive and flexible framework grounded in nonlinear analysis and component-level performance objectives, enabling tailored seismic demand assessments under varying hazard scenarios. The study reveals significant discrepancies in structural performance, material utilization, safety margins, and retrofit implications between the two methodologies. The research advocates for the integration of performance-based assessment techniques, such as those in ASCE 41-17, to more accurately characterize seismic vulnerabilities and inform effective retrofit strategies. The findings support a shift toward more detailed and context-specific evaluation methods to enhance resilience and guide post-disaster reconstruction planning.
Restoring Faith and Form: Reconstruction of Bunga-Dyo (Rato Matsyendranatha) Temple at Bungamati
The paper analyses the community participation in the reconstruction of the Rātō Matsyendranātha temple at Buṅgamati. It was severely damaged in the 2015 Gorkha earthquake and its reconstruction completed after ten years, with a story of resilience, faith and cultural continuity. The reconstruction process changed from contracted construction to a community-led process. This paper further intends to study the process of community building in the core belief system integrated with socio-cultural practices, the challenges of involving stakeholders, local community, national and foreign agencies, which in due course delayed the reconstruction process. The paper claims that the initially ignored local community’s active participation proved vital in restoring and conserving the temple and the site, alongside keeping the faith with the temple intact. The Rātō Matsyendranātha temple reconstruction process that spanned for almost a decade largely saw local community as the primary custodians who ensured ‘authentic’ traditional restoration contesting with the modern-day engineering practice. This study further delves into how reconstruction process can delay due to multifarious challenges involving stakeholders along with local and trans-local agencies. Thus, focusing on the study of community building integrated with socio-cultural practices, also the role of cultural devotion that shaped the successful reconstruction in form and function, giving valuable insight into Nepal’s heritage reconstruction. The paper concludes by reiterating that the restoration of heritage structures is a multiple stakeholder engagement approach where the immediate community’s involvement is crucial in understanding the faith and form of the structure. Hence, it becomes essential to identify the areas of expertise where the local community can equally participate with the experts in the field to ensure the proper reconstruction process, in which the ownership and sense of belonging could be an integral part of such reconstruction process.
Determination of Fundamental Time Period of Bare-Frame Building Incorporating Number of Bays and Storey
The fundamental time period of a building plays a crucial role in determining the base shear during the seismic design of earthquake-resistant structures and is a vital parameter in modal analysis. For structural engineers, the basic knowledge of the fundamental time period is key for efficient and safe design of structures. There are various codes that give an empirical relationship to calculate the fundamental time period of buildings. All these relations are a function of height of the building. However, another influential parameter often overlooked is the number of bays, which directly affects both mass and stiffness, and consequently, the time period. In this study, the fundamental time period of buildings was analyzed incorporating height of building and number of storeys in x and y direction, and an empirical relationship incorporating these factors was created. Modal analysis was carried out in ETABS V17 where 81 models were created by varying storey from 1 to 9 and the number of bays from 2 to 4 in both directions. The storey height and bay spacing were taken as 3.5 m. A regular bare-frame building was analyzed without infill walls to isolate the effect of geometric parameters. Regression analysis was carried out for the time period obtained from the models to propose an empirical relation incorporating height of building and number of bays in both x and y direction using MATLAB code. The model yielded a coefficient of determination (R²) of 0.9902 and RMSE of 0.048 s, showing a strong correlation between predicted and analytical results. The obtained values were compared with empirical code-based expressions (NBC, Euro, IS) and showed deviations upto ±35\%. This indicates that while height remains the dominant factor, inclusion of bay numbers improves accuracy, particularly for bare-frame structures. The study therefore provides empirical expression for fundamental time period of RC bare-frame buildings with number of bay and storey.
Thermal Observation in Vernacular Dwellings of Gurjakhani, Myagdi, Nepal
Indoor air temperature is a key parameter defined by ASHRAE Standard 55 for assessing thermal comfort. Numerous studies have examined thermal comfort conditions in vernacular architecture across different climatic regions. In particular, Dr. Hom Bahadur Rijal and Dr. Sushil Bajracharya, frontiers researchers in this subject have investigated the thermal comfort characteristics of vernacular buildings in high-altitude settlements and Kathmandu valley respectively. This study focuses on the thermal observations of vernacular dwellings in Gurjakhani, Myagdi, Nepal, situated at an elevation of 2638 meters above sea level. The region experiences cool summers, cold winters and occasional snowfall. The local buildings are primarily constructed with stone masonry bonded with mud mortar, while internal partitions are composed of timber planks. The flooring system consists of timber framing with mud overlay, and roofing materials typically comprise stone slates. The houses vary in height from one to three stories. Field measurements of indoor air temperature and surface temperatures within a designated room were conducted using available electronic sensors. Supplementary meteorological data were obtained from online sources to calculate the operative indoor air temperature. The CEB thermal comfort tool was used for thermal comfort analysis. Findings from the one-week field investigation conducted in October indicate that the indoor environment remains cold relative to the calculated operative temperature, yet demonstrated greater thermal satisfaction compared to the outdoor environment.
Development And Evaluation of Response Spectra for Gorkha Earthquake Ground Motion and Using It to Determine Seismic Response of Typical RC Building
e response spectrum, a widely accepted concept used to estimate the lateral forces on the structure, is an envelope of the maximum response of a single degree of freedom (SDOF) system to a particular ground excitation. Since it is very much ground motion dependent and is irregular, it cannot be used directly and has to be smoothed out. It can be used readily to analyse new structures' seismic response and estimate existing structures' response. This study considers 19 ground motion records of 2015 Gorkha Earthquake sequence. These are categorized by magnitudes for rock sites in Kathmandu Valley using Newmark-Beta time stepping method implemented in Python, where elastic response spectra were computed and median and 84.1th percentile design spectra developed. Comparison with the design spectra of the Nepal Building Code (NBC 105:2020), Indian Standard (IS 1893:2016) showed that Gorkha Earthquake (GEQ) based spectra for larger magnitudes(Mw> 6) exceeded the code values in the displacement-dominated period range (T>2s). Practical implications were evaluated through the analysis of a typical RC building in ETABS. The seismic demand computed using the GEQ-based spectra, in terms of base shear, story displacement, and inter-story drift, is significantly lower compared to that of code based spectra.
Study on Damping Property and Vibration Behaviour of SDOF System
The damping ratio is a critical parameter in vibration analysis, representing the energy dissipation capacity of structural components. Accurate assessment of damping behaviour is essential for predicting the dynamic response of structures such as machinery, buildings, and bridges. This study aims to determine the damping ratio of a SDOF system using the logarithmic decrement method. Physical SDOF system were fabricated from mild steel sections measuring 20 mm in width and 3 mm in thickness, with a 1 kg lumped mass attached at the free end to simulate dynamic loading. Free vibration tests were conducted, and displacement-time data were measured using a VLX50LOX sensor. The damping ratio were calculated by applying the logarithmic decrement formula to the decay of successive vibration amplitudes. Initially numerical computation was conducted by setting the time periods between 0.5 and 1.5 seconds by varying length of SDOF system. The Rayleigh method, Finite Element Method (FEM) and the lumped mass concept were used to calculate corresponding SDOF system length. Means of the sum of lengths calculated at each time period were applied to the analysis of SDOF system using ETABS application software. The preparation of physical specimens was based on these numerical findings, and free vibration experiments were carried out on fabricated specimens. The displacement vs time was measured by a VLX50LOX sensor, and then damping ratio with logarithmic decrement method was determined. The damping ratios obtained for the SDOF specimens were from 0.0042 to 0.0055. This setup can be used as an experimental apparatus for studying a single-degree-of-freedom (SDOF) system in the laboratory.
Determination of the Dynamic Characteristic of the Multi-Tiered Bhairabnath Temple in Damaged and Post-Reconstruction State Using Microtremor
Historical structures that have endured for centuries present unique challenges for seismic assessment due to uncertainties in material properties, construction techniques, and the cumulative effects of past modifications and damage. Dealing with such complexity can be time-consuming and challenging. However, using a non-destructive vibration test for seismic assessment of the historical structure is a widely adopted and reliable method for understanding global behaviour. This study performed the ambient vibration tests of the Bhairabnath temple of Bhaktapur, Nepal, to investigate its dynamic characteristics. The vibration tests were conducted in the damaged and post-reconstruction phases. It shows the identified predominant frequency of X and Y direction of the structure in the damaged state are 1.51 and 2.29 Hz, respectively, slightly lower than the post-reconstruction state, which are 1.59 and 2.5 Hz, respectively. This reduction in the structural frequency is attributed to the reduction in the global stiffness, demonstrating the increased structural flexibility. In the post-reconstruction state, operational modal analysis was performed using enhanced frequency domain decomposition and stochastic subspace identification to obtain its dynamic characteristics. The reliability between the two techniques was evaluated using the cross-matrix assurance criteria, which demonstrate a strong correlation between the obtained frequencies and mode shapes. Similarly, the discrepancies in principal directions are 5.3% and 9.17% correspond to the different structural states, which indicate a reduction of 10% and 17% structural stiffness in the damaged state. Hence, the study underscores the significance of vibration test in determining the dynamic properties of the structure and highlights the necessity of structural health monitoring in historical structures.
Soil Structure Interaction Effect in Foundations
A foundation transfers a portion of a structure's weight to the earth. The traditional method of isolated and eccentric footing has been replaced by mat foundation in recent trends. Nevertheless, the concept of soil structure interaction (SSI), which refers to the qualities of the soil in contact with the foundation, has not been implemented in detail in reality. Research has shown that integrating soil structure interaction (SSI) has a major impact on a structure's performance. Winkler’s approach was employed in our work to mimic the spring-like foundation soil. This study details how several foundation types, including combined footing, strap footing, and eccentric isolated footing, affect the RC-frame structure's dynamic properties, including base shear, roof displacement, and natural time period. For all foundation types, the SSI impact revealed an increase in the structure's roof displacement; however, the effect is more pronounced in the case of an eccentric isolated foundation. Roof displacement was used as a performance criterion to assess the constructions' performance. This research analyses changes in base shear, roof displacement, and natural time period as a result of taking SSI into consideration. It ends with a call for SSI to be taken into account in structural analysis and design.
Seismic Microzonation of Kathmandu Valley: Integration of Borehole Data, Microtremor Survey, and Numerical Evaluation
This Kathmandu Valley by integrating borehole data, microtremor survey results, and numerical evaluation techniques to assess soil liquefaction potential. Microtremor measurements were collected from 75 stations throughout the valley, and the vulnerability index (Kg) was calculated using Nakamura’s method, which factors in fundamental frequency and amplification characteristics. The resulting Kg values ranged from 0.091 to 13.463, highlighting the varying liquefaction risk across the valley. Borehole data from 29 excavation sites were used to validate the liquefaction potential, and a threshold Kg value was established in alignment with prior research benchmarks. Numerical evaluation through finite element modeling (FEM) using PLAXIS-2D was performed to further assess liquefaction susceptibility. The FEM analysis confirmed areas with a Kg value greater than 5 as highly vulnerable to liquefaction, while other regions exhibited low susceptibility. Liquefaction susceptibility maps identified critical high-risk zones, particularly in Kathmandu, including areas near Kantipath, Maitighar, and Teku, as well as in Lalitpur and Bhaktapur, such as near Chakupat, Patan Durbar Square, and Bhaktapur Durbar Square. This study demonstrates that integrating microtremor survey data, borehole information, and numerical analysis offers a comprehensive, reliable approach for seismic microzonation and liquefaction risk assessment in earthquake-prone regions like Kathmandu Valley.
Design Validation of Mass Accommodation Structures During The Mw 7.8 Gorkha Earthquake (2015) from A Soil-Structure Interaction Perspective
The seismic response of the structure with underground stories is observed with the consideration of soil structure interaction (SSI). The soil is replaced by springs assigned at the joints. The spring parameters are calculated from ASCE and contemporary literature. The study is conducted on three sets of building with three stories. Two input motions, i.e. Gorkha-Barpak (2015) earthquake time history and time history matched with response spectrum for medium soil from IS 1893 (Part 1): 2002 is used for the analysis. The response of the structure is compared in terms of the time period, roof displacement and shear force demand at ground floor level. The study reveals that on considering SSI, there is an increase in the lateral time period of the building, resulting in a decrease in shear force demand and an increase in lateral displacement. However, the change in the demand is observed to be low and would rarely alter the design of the structure.
Enhancing Seismic Performance of High-Value Buildings Using Viscous Wall Dampers: A Case Study of a Multi-Tower Commercial Facility
High-value and mission-critical facilities—including premium commercial buildings, luxury residences, hospitality developments, hospitals, and data centres—require much higher levels of seismic performance. These building types must not only protect life safety but also ensure operational continuity, minimize functional downtime, and safeguard sensitive interior systems and equipment. Traditional code-based seismic design relying primarily on strength and ductility may not be adequate to meet these stringent performance requirements. This paper evaluates the effectiveness of Viscous Wall Dampers (VWDs) in improving seismic resilience for such high-performance buildings. A detailed nonlinear time history analysis was conducted for a real multi-storey, multi-tower reinforced concrete building consisting of 3B+G+11 and 3B+G+8 storey towers. Nine ground motions were used, and 160 VWDs (64 in X and 96 in Y) were optimized and incorporated. The results demonstrate a reduction in interstorey drift (from ~1% to <0.4%), and major reductions in base shear and floor accelerations. These findings confirm that VWDs offer a highly reliable, architecturally compatible, and performance-driven seismic solution for a broad class of buildings — particularly commercial towers, hotels, high-value residences, hospitals, and data centres, that must remain operational after an earthquake.
Cultural Heritage Damage and Post-Disaster Recovery Under Compound Hazards: The Noto Peninsula Earthquake of January 1, 2024 Followed by Extreme Rainfall
A devastating earthquake hit the Noto Peninsula in Japan on the first day of 2024, a region rich in history, culture and nature, caused serious damage to those heritages. The present paper introduces the earthquake damage to cultural heritages together with the damage related to outlines of the major earthquake. Recovery of the damaged cultural heritages started on the basis of the disaster prevention measures that had been developed since the Kobe Earthquake in 1995. However, during the process of recovery phase, the earthquake-affected areas in the Noto Peninsula suffered further damage from the disastrous rainfall in September, 2024. In the present paper, the earthquake damage to the cultural heritages are reviewed with being followed by the further damage caused by the heavy rainfall in order to share our experience internationally.
Effect of Unauthorized Addition of Storeys in a Residential Building
In Nepal, it has become common practice to add stories and projections, without legal authorization and proper design for these extensions, which has led to much damage as observed in the recent 2015 Gorkha earthquake. Therefore, this paper studies the effect of unauthorized addition of storeys by FE modelling using response spectrum method. Two cases were considered: (1) replication of a typical storey until structural failure, (2) incorporation of 1-ft, 2-ft, and 3-ft extensions along with stepped projections, followed by vertical replication until failure. The study found that base shear and storey drift at the top storey increased with the addition of the first storey due to increased seismic mass but gradually decreased as more storeys were added. The ground and first floors were found to be most vulnerable to structural failure due to unauthorized addition of storeys particularly in cases coupled with horizontal extensions.
The Role of Iconography in the Restoration of Laxmi-Narasimha Temple
The Laxmi-Narasingh Temple, originally built in the 14th century on a square base with a two-tiered roof, holds significant historical and cultural value. In the 16th century, the temple underwent renovation, during which a semi-basement was added at the southeast corner of the lower plinth. This section houses a shrine to Tole Ganesha, an important figure which still has deep social and religious relevance for the local community. Photographic evidence from 1912 shows the temple in a severely deteriorated state, with only one storey remaining, marked by beautifully crafted central and side windows (ga-jhya). The temple was completely destroyed in the 1934 earthquake, leaving only the base structure (lakanshin) near the central entrance. The temple was reconstructed as a single-storey building with corrugated metal (CGI) roofing and metal-grilled doors on all four sides. This reconstruction was carried out in 1986 under the initiative of King Birendra Bir Bikram Shah Dev to commemorate the visit of Queen Elizabeth II. Further reconstruction work was later undertaken by Bhaktapur Municipality, in coordination with the Users’ Committee, heritage conservation experts, and engineers from Khwopa Engineering College and Khwopa College of Engineering. The restoration process involved studying several similar heritage structures as case studies and relied heavily on historical documents, remaining artifacts, traditional knowledge, and expert consultation. A reconstruction proposal by the late Surendra Joshi, a draughtsman involved in the Bhaktapur Development Project (BDP), also played a key role. This paper focuses on the importance of traditional iconography in restoring cultural monuments and discusses the challenges faced during the reconstruction. It also draws from interviews and literature reviews to explore various iconographic figures essential to the temple’s design especially for door portals, struts, windows and tympanum. The Laxmi-Narasingh Temple serves as a model example of heritage restoration, especially in situations where historical details are incomplete or unclear.
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Spatial and Architectural Analysis of Rural Settlements: A Case Study of Vernacular Architecture in the Chhantyal Village of Gurja Khani, Dhaulagiri, Nepal
The vernacular settlement of the Chhantyal community in Gurja Khani village, located in the Dhaulagiri region of central-western Nepal, remains vibrant and continues to reflect the socio-cultural heritage, historical continuity, and sustainable lifestyle of this rural society. This study offers a comprehensive analysis of Gurja Khani, examining its geographical context, settlement patterns, community structure, clustered housing arrangements, social organization, and ritual practices. The research identifies and categorizes three primary dwelling typologies based on their morphological development and functional characteristics: (1) the original form of dwellings, (2) evolved forms with extended porches, and (3) dwellings exhibiting variations in form and number of storeys. These typologies are analyzed in relation to construction techniques, spatial organization, and community usage of open spaces, both within and around the dwellings. The integration of building materials and construction methods with the local terrain and climatic conditions demonstrates an adaptive architectural approach, resulting in a settlement that is ecologically responsive and socially cohesive. This vernacular architecture not only sustains traditional lifeways but also embodies the identity and collective memory of the Chhantyal community and their place in the landscape.