The University of Danang - Journal of Science and Technology

A RECSA approach to measuring intercity bus service quality bridging the gap between expectations and performance

Vu Van-Huy — 2025-10-31

This study evaluates the quality of intercity bus services in Hanoi, Vietnam, from passengers’ perspectives using the RECSA framework to measure gaps between expectations and perceptions. A questionnaire survey was conducted at major intercity bus terminals, including Giap Bat, My Dinh, and Yen Nghia, to collect data on five core service dimensions: reliability, extent of services, comfort, safety, and affordability. From 240 collected responses, 199 valid samples were analyzed. Paired-sample t-tests identified significant differences between expectations and experiences, especially in reliability, affordability, and comfort. The results revealed significant differences between passengers' expectations and actual service experiences, particularly in the areas of reliability, affordability, and comfort. The findings suggest that a more consistent and comfortable service offering, alongside fair pricing, is crucial for meeting passenger expectations and improving overall service quality. The study offers practical insights for bus operators, policymakers, and planners to enhance intercity bus services and customer satisfaction.

A review on lateral response of DCM and a case study

Erwin Oh — 2025-10-31

Deep cement mixing (DCM) is one of the geotechnical solutions to support an embankment. The horizontal bearing capacity of the DCM is insufficient to resist high lateral loads, which may lead to large horizontal displacements or even failures of the structure. Therefore, the lateral resistance of the DCM material is the main challenge that needs to be studied in depth. Lateral resistance improvement methods, such as using steel beams, concrete piles, T-shape columns, fibres, anchors, and PVDs, are presented based on previous research. A case study at the Hiep-Phuoc Container port project in Vietnam is used to analyse failure reasons and recommendations provided.

An application of Building Information Modeling (BIM) in construction schedule management – a case study of olalani riverside tower project

Van-Thi Nguyen — 2025-10-31

This study focuses on the research and application of Building Information Modeling (BIM), specifically BIM 4D – the integration of time (schedule) into a 3D model – to enhance the effectiveness of construction schedule management. Through theoretical analysis, assessment of current practices, and practical application of BIM 4D at the Olalani Riverside Tower project in Danang city, the study highlights the significant potential of this technology in visualizing construction methods, monitoring progress, facilitating coordination, and improving accuracy in project execution. This research has cleared up the effectiveness of applying BIM in construction schedule management to a specific project, demonstrating benefits in areas such as enhanced visualization of construction methods, optimized scheduling and resource allocation, improved coordination among project stakeholders, and effectiveness in communication efforts. Consequently, it contributes to reinforcing and promoting the broader adoption of BIM and a more robust digital transformation in the construction industry.

Analyzing key factors and strategic solutions for railway infrastructure maintenance in Vietnam: a case study approach

Nguyen Quang Trung — 2025-10-31

The study examines the factors affecting the quality of railway infrastructure maintenance at Quang Nam – Da Nang Railway Joint Stock Company (QNDN Railway). Through a survey and SWOT analysis, it identifies key factors such as management issues, economicand technical challenges, and the effects of terrain and weather on maintenance operations. The analysis outlines the company’s internal strengths and weaknesses, as well as external opportunities and threats. Based on these findings, the study proposes several improvement strategies, including strengthening management capacity, modernizing maintenance technology, and fostering international cooperation. These solutions aim to enhance the effectiveness and sustainability of railway infrastructure maintenance at QNĐN Railway and could be applied to other railway companies in Vietnam, contributing to the overall efficiency of the national rail system.

Application of advanced technology in architectural heritage conservation: experiences from France and directions for Da Nang City

DUONG Hung-Minh — 2025-10-31

The preservation of architectural heritage plays a crucial role in maintaining historical, cultural, and artistic identities, particularly in the context of urbanization and environmental changes today. France, with its rich architectural heritage and advanced preservation techniques, serves as an exemplary model in this field. This study aims to achieve two objectives: first, to introduce modern preservation methods currently applied in France and second, to propose suitable directions for architectural heritage preservation in Da Nang city. Based on field surveys of notable landmarks such as Notre-Dame Cathedral in Paris, the historic districts of Aix-en-Provence, and Marseille, the authors analyze the technologies being implemented and draw lessons from these experiences. Based on these findings, the study suggests technological solutions to enhance the effectiveness of preservation efforts and promote the sustainable development of architectural heritage in Da Nang city.

Assessing the distribution of green space and proposed solutions to enhance people's access to green space in Thanh Khe, Cam Le, Hai Chau districts, Da Nang City

Do Hoang Rong Ly — 2025-10-31

Urban green spaces (UGS) provide essential ecosystem services that enhance health, quality of life, and support the achievement of the United Nations’ Sustainable Development Goals, particularly Goals 3 and 11. However, equitable access to UGS remains a challenge in many urban areas. This study analyzes the accessibility of UGS for residents in three districts of Da Nang - Thanh Khe, Cam Le and Hai Chau - based on factors such as geographic distribution, transportation infrastructure, demographic characteristics, and green space functionality. Through field surveys and public feedback, the study assesses usage needs and perceived benefits related to physical and mental health, as well as social interaction. Based on these findings, the authors propose technology-integrated solutions for designing and managing UGS to improve equitable access, enhance community engagement, and promote smart, sustainable urban development.

Assessment of the stability of critical landslide sites along the Hoa Trung Lake boundary road - Da Nang Hi-Tech Park

Vo Ngoc Duong — 2025-10-31

Changes in water flow, combined with infrastructure development, have altered the natural land cover one of the major causes of erosion and instability in the area with significant impacts on socio-economic development" In this study, the research team developed a landslide hazard zoning map for the area surrounding Hoa Trung Lake and the Da Nang Hi-Tech Park, using the Analytic Hierarchy Process (AHP) method with seven factors: slope, rainfall, distance to roads, soil type, land use, topography, and geomorphology. The study also employed the GEO-STUDIO modeling suite to calculate stability coefficients for 14 representative cross-sections, under three heavy rainfall-induced disaster risk scenarios (Scenario 1, Scenario 2, and Scenario 3). The results indicate that cross-sections 1, 4, 5, 6, and 10 are at high risk of landslides under the rainfall conditions represented by Scenario 2 and Scenario 3.

Calibration of time–domain reflectometry (TDR–315H) sensor for volumetric water content measurements in recycled roadbed materials

Van Nam Pham — 2025-10-31

Permeable pavement systems (PPS) are widely adopted in developed countries for urban flood control and heat island mitigation challenges, but have not yet been widely used in Vietnam. Monitoring volumetric water content (θ) in roadbed materials is essential for evaluating their performance for abovementioned challenges at pilot-scale. The Time Domain Reflectometry (TDR) technique is commonly used for measuring θ but requires a material–specific calibration for θ values. This study aims to establish calibration curves for roadbed materials by using a commercially available sensor of TDR-315H. Two types of materials were tested in the laboratory: (i) unbound roadbase materials including recycled concrete aggregates (RCA), RCA blended with autoclaved aerated concrete grains, and natural aggregates, and (ii) RCA combined with recycled brick aggregates and cement as a bound porous surface. The results showed that sensor manufacturing variability was negligible, and specific calibration curves were successfully developed for each material.

Capsule-like smart aggregate-based concrete stress monitoring via impedance signals: numerical study

Pham Quang Quang — 2025-10-31

This study numerically explores the feasibility of a capsule-like smart aggregate (CSA) for monitoring stress in concrete using an impedance-based approach. After a brief introduction to the core principles of impedance-based structural health monitoring (SHM), a finite element model of a concrete cylinder embedded with a CSA sensor is developed. Impedance responses are analyzed under varying levels of axial compressive stress. Variations in the CSA’s impedance response due to applied stresses are analyzed through shifts in the frequency and amplitude of resonant peaks and quantified using the Root Mean Square Deviation (RMSD) index. The results demonstrate that the CSA sensor exhibits clear sensitivity to compressive stress changes, confirming its feasibility for stress monitoring in concrete structures.

Carbonation behaviour of concrete considering the constituents of coarse aggregate

Tien-Dung Nguyen — 2025-10-31

This study investigates the carbonation behavior of recycled aggregate concrete (RAC) considering the constituents of coarse aggregate (CA). Coarse natural aggregate (CNA) was replaced with coarse recycled aggregate (CRA) at 0%, 20%, 40%, 60%, 80%, and 100%. The CA constituents such as Rc, Ru, Ra, Rb, and Rg were determined according to NF EN 933–11 by manual sorting before casting. Accelerated carbonation tests were performed to evaluate carbonation depth and rate. Results indicate that the variability in CA composition significantly influences RAC carbonation behavior, with strong correlations (R² > 0.9) observed between Rc and Rb contents and the carbonation performance of RAC.

Compressive strength and behavior analysis of full-scale concrete filled steel tubular columns

Hao Dinh Phan — 2025-10-31

This paper investigates the compressive behavior of full-scale concrete filled steel tubular (CFST) columns with varying heights, loading conditions, and constituent material strengths. A numerical study was conducted on eighteen CFST specimens with steel yield strengths (f_y) ranging from 620 to 690 MPa and concrete compressive strengths (f_c’) ranging from 80 to 100 MPa. Two concentric loading types were applied: over the entire cross-section (CFE) and on the concrete core only (CFC). Results indicate that both loading type and material strength significantly affect column performance. CFC-loaded columns achieved higher compressive strength but lower deformation capacity compared to those under CFE loading, due to variations in the confinement effect provided by the steel tube. Increasing f_y and f_c’ enhanced overall column’s compressive strength, while higher f_c’ led to greater concrete core damage. The AS/NZS 2327: 2017 design standard provides conservative yet reliable strength predictions for CFST columns constructed with high strength materials.

Development of a machine learning model for in-motion train weight estimation on railway bridges

Tran Le Anh Duc — 2025-10-31

This paper presents a fast, accurate approach for estimating train weight during bridge crossings by coupling a validated train–track–bridge dynamic interaction model with an XGBoost regressor optimized via Bayesian hyperparameter tuning. A high-speed railway bridge in China is used as a case study. We generate a dataset of 1000 labeled samples from finite-element dynamic simulations driven by Latin Hypercube Sampling, and validate the interaction model against available experimental data. The learned model maps measured bridge responses to train loads and is suitable for real-time deployment. Results show high predictive accuracy, with coefficients of determination R² ≈ 0.996 for motor cars and 0.993 for trailer cars. Gain-based feature importance indicates that the bridge’s maximum vertical displacement during passage is the most influential input, substantially outweighing other variables. The proposed framework demonstrates a practical path toward in-service train load estimation and monitoring without intrusive onboard sensors or extensive instrumentation.

Experimental study on determining the effective radius of blasting and pile-driving activities on construction structures

Thai Hoang An — 2025-10-31

Accurately determining the effective impact radius of construction-induced vibrations, such as those caused by vibratory roadbed compaction, pile driving, and rock blasting, is essential for ensuring the safety of adjacent structures and minimizing disputes in infrastructure projects. This study experimentally investigates the propagation and attenuation of shock waves generated by blasting and pile-driving activities in typical geological conditions in Central Vietnam. Field measurements of peak particle velocity, acceleration, and noise levels were conducted using calibrated sensors in accordance with national standards (TCVN 7378 and QCVN 27:2010/BTN-MT). The experimental data were analyzed to derive empirical relationships between vibration intensity and distance from the source, enabling the estimation of safe construction distances for various structural types. The results show strong agreement between theoretical models and in-situ measurements, validating the proposed approach and offering practical guidance for infrastructure design, construction planning, and regulatory compliance.

Influence of anchor inclination and length on the stability of excavated roadbed slopes reinforced with anchors

Vo Hai Lang — 2025-10-31

This study investigates the influence of anchor angle and anchor length on the stability of roadbed slopes. The study is based on a cut slope with height H=21 meters, divided into three levels and considering three different geological configurations. Two slope ratios are analyzed: 1:0.5 and 1:0.75. Conventional steel anchors are used and the theoretical basis is the numerical method. The stability of the slope is analyzed using FLAC software with the theoretical basis of the finite difference method. The study determines the optimal anchor angle by evaluating the range from 20°, 25°, 30°,..., 50°. The study also compares two reinforcement scenarios: 9 anchors with a length of 8 meters and 6 anchors with a length of 10 meters, to determine the most reasonable configuration. In addition, the critical sliding surface corresponding to each optimal anchor angle is determined.

Numerical modeling of the turbid tropical Cointzio Reservoir, Mexico

Phuong T. K. Doan — 2025-10-31

The Cointzio Reservoir in central Mexico faces significant degradation due to urban expansion and agricultural activities, leading to high turbidity and eutrophic conditions. Surface chlorophyll-a concentrations (~70 µg L⁻¹) indicate harmful algal blooms, and sedimentation has reduced storage capacity by 20-25%. A coupled numerical model combining a 1-D hydrodynamic module with the ecological model Aquasim was used to simulate seasonal stratification, mixing dynamics, sediment accumulation, and nutrient-phytoplankton interactions. Model results aligned with field observations, demonstrating its effectiveness in capturing the main mechanisms of water quality decline. This study highlights how integrated physical and ecological models can aid reservoir management in regions with heavy nutrient and sediment loading.

Optimisation design of precast reinforced concrete sheet piles for coastal retaining walls

Van-Ngoc Pham — 2025-10-31

This research introduces a novel method for optimising the design of precast reinforced concrete (SW) sheet piles that are used in coastal retaining walls. The study examined key parameters, including backfill embankment height, surcharge loads, and SW sheet pile geometry to evaluate the stability and performance of a retaining wall. Using the Python-Plaxis interface, a set of numerical models were developed automating the analysis and significantly reducing computational time. In total about 70 models were conducted; their results were used to establish a Gene Expression Programming (GEP) model between input and output parameters. The research results confirm that combining FEM and GEP is a valid approach for design optimisation of complex geotechnical structures. A parametric study indicated that the height of backfill embankment and the length of SW piles are critical variables. This integrated approach provides engineers an efficient tool in the design of soft soil in coastal regions.

Performance-based study of long-span steel–concrete composite trusses for high-rise structures

My PHAM — 2025-10-31

This study presents a comprehensive evaluation of long-span steel–concrete composite trusses for high-rise buildings, integrating Eurocode-based theoretical analysis with finite element modeling (FEM). A performance-based design methodology is proposed, enabling efficient cross-section selection during the construction stage. This approach not only enhances structural efficiency and serviceability but also significantly reduces design iterations and construction complexity. The close agreement between analytical and numerical results confirms the reliability of the proposed method and reinforces its applicability to real-world projects. The findings provide valuable insight into the structural behavior of composite trusses and establish a robust foundation for their broader use in high-rise applications demanding performance-driven and material-efficient solutions.

Study on spatial organizing for sustainable tourism development: application in Thai Lai Village, Da Nang City

Le Minh Son — 2025-10-31

Reconstructing Thai Lai Countryside with a focus on sustainable tourism development. The reconstruction of Thai Lai countryside focuses on reorganizing architectural landscape spaces while preserving cultural and historical values. Proposed solutions include improving landscape quality, enhancing infrastructure, and organizing spaces through models such as rest stops, agricultural outlets, outdoor zones, and riverside corridors. These are based on SmartCode and MCA principles to ensure effective planning and protect rural identity. Collaboration among the community, businesses, and government is essential for sustainable tourism. The plan aims to boost local economic conditions and transform Thai Lai into a model rural area, offering a scalable solution for similar regions and contributing to the sustainable cultural development of Hoa Vang.

The role of policy awareness in predicting intention to use electric motorcycles: an extension of TPB model

Nguyen Van Bien — 2025-10-31

The growing reliance on gasoline-powered motorcycles has exacerbated air pollution in many urban areas. Electric motorcycles have emerged as a sustainable alternative, yet consumer adoption remains limited. This study extends the Theory of Planned Behavior (TPB) by incorporating policy awareness to explain better the intention to use electric motorcycles. Using data from 525 non-users in Da Nang City, Vietnam, analyzed via Partial Least Squares Structural Equation Modeling (PLS-SEM), the results show that personal norms and perceived behavioral control significantly influence the intention to use electric motorcycles. These findings highlight the importance of policy awareness, psychological determinants, and perceived value in fostering electric motorcycle adoption and developing effective environmental strategies.

Toward the future necessity of timber construction and its longevity in Japanese wooden architecture

Otake Miyu — 2025-10-31

This research examines a rational maintenance management for wood by verifying the effectiveness of surface protection coatings, aiming for the long-term durability and versatility use of wooden materials. In recent years, the use of wooden materials has been legally promoted toward achieving a decarbonized society; however, the wooden materials performance challenge of being vulnerable to global warming are keeping. In this study, the effects of protective coatings, such as penetrating paints and acrylic silicon-based coatings, were compared on wooden materials used in various applications, such as residential and public facilities, and the color changes and durability of the wooden materials were evaluated. Additionally, the selection of coatings according to the place of use and purpose for example, using natural coatings in areas where children may touch was considered, demonstrating the importance of enhancing weather resistance while maintaining the wood's texture.

Two-dimensional numerical simulation of the effect of porosity on the compressive strength of concrete

Thanh Hai Nguyen — 2025-10-31

Concrete is widely used in construction due to its versatility, durability, and low cost. Porosity, defined as the ratio of voids, significantly affects compressive strength. This study uses 2D numerical simulations with the discrete element method (DEM) and Voronoi tessellation to model internal voids, examining porosity from 1% to 15%. Results show that porosity strongly influences both compressive strength and strain in concrete. When porosity increases from 3% to 5%, the compressive strength decreases by 13–33%. Notably, at 15% porosity, the compressive strength is reduced by up to 80% compared to the 1% porosity case. Interestingly, both maximum compressive strength and strain show an exponential dependence on porosity. These findings highlight that, in addition to other material properties, porosity is a key factor in determining the compressive strength of concrete. This study aims to enhance understanding of concrete behavior, contributing to improved performance and sustainability in construction.

Utilizing coal bottom ash as a fine aggregate in mortar: the effectiveness of pre-treatment methods

Trong-Phuoc Huynh — 2025-10-31

The increasing demand for sustainable construction materials has encouraged the use of industrial by-products as sand replacements in mortar. Coal bottom ash (CBA), a by-product of thermal power plants, shows potential as a fine aggregate but has high porosity and weak bonding. This study examines Na₂CO₃ pre-treatment (0.1 M and 0.25 M) to enhance performance of CBA a full sand replacement in mortars. Mechanical strength, ultrasonic pulse velocity (UPV), drying shrinkage, water absorption, and rapid chloride ion penetration (RCPT) were tested. At 28 days, 0.25 M-treated CBA increased flexural and compressive strengths by 44.5% and 29.9%, respectively, and UPV by 6.6%. Drying shrinkage and water absorption decreased by 18.2% and 13.6%, while RCPT dropped 20.1%. These findings confirm that Na₂CO₃ pre-treatment, particularly at 0.25 M, markedly improves strength and durability, making CBA a viable and sustainable fine aggregate alternative.