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Shear Behavior of Small-Scale Continuous Hidden Beams Using Tied and Spiral Stirrups
No full textHidden beams in reinforced concrete (RC) structures are widely used to meet architectural requirements; however, their reduced effective depth limits shear capacity. This study investigates the shear behavior of hidden beams reinforced with innovative rectangular staggered continuous spiral stirrups, addressing the absence of design guidelines for such reinforcement systems. Nine one-eighth-scale continuous beams were tested under two-point loading, with mortar used to reduce scale effects. The influence of the number, geometry, and configuration of spiral reinforcement was investigated. Both conventional and spiral stirrups significantly improved shear performance compared to the reference beam without transverse reinforcement (HB9-No). Beams with normal stirrups (HB1-N20, HB2-N30, HB3-N40, HB4-N50) increased shear capacity by 115%, 82%, 23%, and 4%, while spiral stirrup beams (HB1-S20, HB2-S30, HB3-S40, HB4-S50) achieved corresponding increases of 174%, 144%, 73%, and 27%, respectively. Overall, spiral reinforcement enhanced shear capacity and energy dissipation by approximately 30% and 46%, respectively, compared with conventional stirrups. Prototype capacities estimated using scaling relationships were compared with international design codes, which were found to be conservative. The findings demonstrate the effectiveness of spiral stirrups in improving shear strength and ductility and emphasize the need to include their contribution in future shear design equations for hidden beams
Unveiling the Barriers to Value Management Implementation in Building Projects: An Integrated EFA-SEM-ANN Analysis Approaches
No full textValue Management (VM) is a structured method for enhancing the effectiveness of building projects, yet adoption in Jordan remains limited. The study identifies the principal barriers to VM adoption in Jordan’s building sector and ranks them to inform policy and practice. A survey of 101 industry stakeholders captured 19 Likert-type indicators. Exploratory factor analysis (EFA) reduced the indicators to coherent barrier clusters; partial least squares structural equation modeling (PLS-SEM) then validated a reflective measurement model and tested links with VM adoption. An artificial neural network (ANN) with k-fold cross-validation quantified predictor importance and assessed out-of-sample error. EFA produced three clusters—standardization and organizational practices, workshop design and participation, and culture and industry environment—explaining approximately 73% of total variance. PLS-SEM supported reliability and convergent/ discriminant validity and indicated that workshop-related and standardization barriers exert the strongest adverse effects on VM adoption. ANN results corroborated these patterns and highlighted workshop dynamics as the most influential predictor. This work presents the first integrated EFA–SEM–ANN analysis of VM adoption barriers in Jordan. The multi-method evidence yields actionable priorities: institutionalize standardized VM procedures, strengthen VM workshop design and participation, and address organizational culture to accelerate VM uptake
High-Resolution Silt Distribution Mapping Using Ordinary Kriging From Borehole Data in a Geohazard-Prone Area
No full textKundasang, Sabah, is one of the most geohazard-prone highland regions in Malaysia. Slope failures are frequently triggered by heavy rain. Silt-rich zones present a particular stability problem, since silt has low cohesion and drains faster than clay, which means that slopes can undergo rapid saturation and lose shear strength during sustained and intense rainfall. Previous research works in Kundasang have focused on landslide susceptibility through rainfall thresholds and GIS terrain analysis. However, depth-specific, high-resolution silt distribution maps have not yet been produced. This study addresses the research gap using geostatistical modeling of geotechnical data from boreholes to map silt distribution patterns. Soil samples from 70 boreholes were analyzed by classifying soil types down to 10 m depth in 2.5 m segments. Using Ordinary Kriging in ArcGIS 10.3, the best-fit semivariogram model for each depth was selected based on the lowest Root Mean Square Error values (ranging from 5.33 to 11.92). The findings reveal that high-silt zones (areas with over 30% silt content) cover around 40% of the study area and cluster mainly in western and northern Kundasang, particularly in the upper 7.5 m of soil. These correspond to areas previously documented as highly susceptible to rainfall-induced slope failures. The depth-specific silt distribution maps produced in this study provide important geotechnical inputs to enhance future landslide susceptibility assessments, improve slope stability analyses, and support risk-informed land-use planning for local authorities in geohazard-prone highland areas
The ITB Unit Hydrograph Method: A Novel Approach to User-Defined Unit Hydrograph Development (Part I)
No full textAll synthetic unit hydrographs can be considered user-defined to some degree, reflecting the inherent influence of user input in their development. This paper constitutes the first part of a two-part series titled The ITB Unit Hydrograph Method: A Novel Approach to User-Defined Unit Hydrograph Development. It focuses on foundational concepts, the verification of existing SUH methods, and the creation of simple user-defined Synthetic and Natural Unit Hydrographs. The verification process involves reproducing established hydrographs, including the SCS-Triangular, SCS-Curvilinear, and SCS-Delmarva models, by computing their Peak Rate Factor (Kp) and Peak Discharge (Qp) values using ITB-UH formulas. Results demonstrate high accuracy, with discrepancies in Kp values consistently below 1%, confirming the reliability of the ITB-UH Method in replicating existing models. Furthermore, the study highlights the ITB-UH Method's capability to develop user-defined synthetic hydrographs, as exemplified by the Double Triangle Synthetic Unit Hydrograph and the HKR Natural Unit Hydrograph. The Double Triangle model introduces a simple unit hydrograph with distinct geometric properties, while the HKR model effectively represents a natural unit hydrograph derived from rainfall-runoff dynamics in a watershed. Both models were applied to flood discharge simulations in the Pinamula Watershed using consistent steps for effective rainfall excess distribution and convolution. The results demonstrate that all hydrographs, despite differences in shape and peak characteristics, yield consistent total flood volumes. These findings underscore the ITB-UH Method's potential to generate unit hydrographs based on user-defined models”whether defined by equations or tables. It should be noted that the simple user-defined unit hydrographs presented in this paper do not include calibration capabilities, a topic that will be explored in Part II of the series. Doi: 10.28991/CEJ-2025-011-04-021 Full Text: PD
The Crack Propagation in Different Rock Types: A Comparative Seismic Simulation
No full textThe presence of a preexisting crack in a rock can affect its stability during seismic events, leading to reduced strength and stiffness. This study, which aims to examine how different types of preexisting fracture angles and the mechanical properties of the rock impact real-time cracking propagation modes and crack propagation shape, has practical implications. The researchers used ABAQUS software to apply simulated seismic loading to their model and studied crack propagation using the extended finite element method (XFEM). They found that the crack propagation shape and real-time cracking propagation vary based on the preexisting fracture angles and the mechanical properties of the rock. Additionally, they observed a significant relationship between strain leading to nonlinear deformations and the mechanical properties and fracture seismic toughness mechanism. These findings can be applied to improve the prediction of failure mechanisms in rocks with different crack shapes and could potentially enhance seismic response simulation and geotechnical earthquake engineering codes. The numerical simulation results were validated and compared to existing literature, further highlighting the practical applications of this study's findings. Doi: 10.28991/CEJ-2025-011-01-01 Full Text: PD
A Study of Biomass Concrete Reinforced with Fiber Composites to Enhance Impact Load Capacity
No full textThis research investigates the energy absorption from impact forces of steel reinforced concrete using fly ash obtained from agricultural processes, reinforced with glass fiber-reinforced polymer (GFRP) bars, compared to steel reinforcement. The reinforcement pattern involves incorporating GFRP bars into a square grid pattern of 4, 9, and 12 openings within bio-steel concrete with dimensions (W í— L í— H) of 40 í— 40 í— 10 cm. The testing is conducted using a Drop Test impact testing machine with a 30 kg hammer head at a velocity of 7 m/s, employing two different hammer head configurations: flat and 45-degree angled, to study energy absorption (Ea), specific energy absorption (Es), and the pattern of deformation resulting from impacts. The study finds that CBRHA-10-fiber A concrete exhibits higher energy absorption and specific energy absorption compared to steel-reinforced (CBRHA-10-steel A) concrete in the same configuration by 18.82% and 26.83%, respectively, in the flat-headed hammer impact configuration. Similarly, in the 45-degree angled hammer head configuration, CBRHA-10-fiber A concrete demonstrates superior energy absorption and specific energy absorption compared to steel reinforcement in the same configuration by 6.10% and 14.92%, respectively. In conclusion, bio-steel reinforced concrete with glass fiber-reinforced polymer (GRFP) reinforcement exhibits good load-bearing capacity and suitability as an alternative to steel reinforcement in future applications. Doi: 10.28991/CEJ-2025-011-02-020 Full Text: PD
Experimental Investigation of Single and Intermittent Light Non-Aqueous Phase Liquid Spills Under Dynamic Groundwater
No full textThe groundwater contamination from petroleum by-products represented in Light Non-Aqueous Liquid (LNAPL) under groundwater table fluctuations has become a serious environmental problem. For this reason, developing a rapid response strategy incorporating experimental characterization of LNAPL distribution trajectories is crucial for assessing the threats of LNAPL contaminants in the subsurface environment. In this study, the influence of various LNAPL spills in a porous medium under dynamic groundwater conditions was investigated using the Simplified Image Analysis Method (SIAM). Single and intermittent LNAPL (diesel) spills of total volume (400 and 800 ml) were examined in a river sand "Žtwo-dimensional tank (70 cm í— 70 cm í— 3.5 cm) under the effect of groundwater table fluctuation. The results indicated that the contaminant was distributed above h=28 cm in the 400 ml LNAPL spill. However, it migrated below h=28 cm, and its saturation reached 36% when the LNAPL volume raised to 800 ml. The LNAPL saturation in the case of four LNAPL intermittent spills was more evenly distributed through the tank depth than in the cases of a single spill of 800 ml and two intermittent spills of 400 ml. Furthermore, LNAPL migrated to a larger depth in the system (h=18.5 cm) only in the case of four LNAPL intermittent spills and under groundwater table fluctuation, which poses a significant threat to the groundwater. This study highlights the importance of the effect of various LNAPL spills under dynamic groundwater conditions, which can offer valuable guidance for developing remediation schemes. Doi: 10.28991/CEJ-2025-011-01-017 Full Text: PD
Development and Validation of a Seismic Index for Assessing the Vulnerability of Low-Rise RC Buildings
No full textThis research develops a comprehensive framework for evaluating the seismic vulnerability of Afghanistan's low-rise reinforced concrete (RC) structures, aiming to enhance urban resilience and mitigate seismic risks. The primary objective is to improve structural safety and reduce economic losses and casualties during devastating earthquakes. Utilizing a database of low-rise RC buildings constructed between 2001 and 2022 by the Ministry of Urban Development and Housing (MUDH) and the Ministry of Education (MOE), the study analyzes structures with varying materials, architectural styles, construction years, and number of stories. The methodology integrates a modified Japanese Is Index, refined using statistical techniques to incorporate local seismic data and building characteristics across diverse seismic zones. Advanced analyses, including the Capacity Spectrum Method (CSM) and dynamic analysis using STERA 3D software, support the development of the Afghanistan Seismic Index (ASI). Findings confirm ASI's reliability by comparing it to existing seismic assessment methods, demonstrating its suitability for region-specific evaluations. The research proposes a novel, tailored seismic index (ASI) for assessing seismic vulnerability and addressing gaps in Afghanistan's building code (ABC) and standards. This framework enhances structural performance and informs future policy, providing a foundation for safer urban environments and sustainable infrastructure development in earthquake-prone regions. Doi: 10.28991/CEJ-2025-011-03-016 Full Text: PD
Strength, Water Porosity and Sulfuric Acid Performance of Coconut Fiber Reinforced High-Strength Concrete
No full textThis study investigates the use of coconut fibers (CFs) derived from coconut husks to enhance the performance of high-strength concrete (HSC), aligning with sustainability goals through the reuse of agricultural waste. The objective was to assess the strength properties, water porosity, and sulfuric acid resistance of coconut fiber-reinforced high-strength concrete (CFR-HSC), targeting a mean compressive strength of 60 MPa. CFs underwent an alkali treatment involving boiling for one hour followed by immersion in a 1% sodium hydroxide (NaOH) solution, which improved their surface morphology as confirmed by scanning electron microscopy (SEM). Concrete specimens with CFs contents of 0.25, 0.5, 1.0, 1.5, and 2.0% were evaluated. Increased CF contents content reduced workability and dry density, while compressive strength at 7 and 14 days improved by 2.31 and 13.02%, respectively, at 0.5% CF content but showed no significant improvement at 28 days. However, tensile and flexural strengths improved significantly, achieving the highest gains of 34.71 and 7.03% at 1% CF content, respectively. CFR-HSC exhibited increased water porosity but enhanced resistance to sulfuric acid, indicating improved durability under aggressive environments. These findings demonstrate the potential of NaOH-treated (NT) CFs to enhance tensile and flexural properties while improving chemical durability, offering a sustainable approach to advancing HSC performance. Doi: 10.28991/CEJ-2025-011-04-023 Full Text: PD
On the Impact of Lacing Reinforcement Arrangement on Reinforced Concrete Deep Beams Performance
No full textThe optimum design is characterized by structural concrete components that can sustain loads well beyond the yielding stage. This is often accomplished by a fulfilled ductility index, which is greatly influenced by the arrangement of the shear reinforcement. The current study investigates the impact of the shear reinforcement arrangement on the structural response of the deep beams using a variety of parameters, including the type of shear reinforcement, the number of lacing bars, and the lacing arrangement pattern. It was found that lacing reinforcement, as opposed to vertical stirrups, enhanced the overall structural response of deep beams, as evidenced by test results showing increases in ultimate loads, yielding, and cracking of 30.6, 20.8, and 100%, respectively. There was also a 53.6% increase in absorbed energy at the ultimate load. The shear reinforcement arrangement had a greater impact and a significant effect on the structural response than the number of lacing bars. For lacing reinforcement with a phase difference equivalent to the half-lacing cycle (i.e., phase lag lacing), the percentage of improvement under different loading stages was 6.7-27.1% and 20.8-113.3%, respectively. The structural responses are significantly impacted by the lacing arrangement; members with two and three lacing bars, respectively, exhibited improvements in ultimate load of 30.6% and 47%. Beyond the yielding stage, the phase lag lacing specimens deviated from those without phase lag lacing and normal shear stirrups because of the lacing contribution. Phase lag specimens showed more strain than specimens without phase lag lacing, meaning that the lacing reinforcement contributed more to the beam strength. It was found that the first shear cracking load of all the laced reinforced specimens was higher than that of the conventional shear stirrup specimens. Phase lag lacing produced the greatest improvement, with two bars achieving 92.44% and three bars achieving 217.07%. For the aforementioned number of bars, lacing shear reinforcement without phase lag was less successful, with 36.91% and 46.53%, respectively. Doi: 10.28991/CEJ-2025-011-02-019 Full Text: PD