Journal Title : U Karst Publication Frequency : Biannual (April and November) DOI : http://dx.doi.org/10.30737/ukarst Print ISSN : 2579-4620 Online ISSN : 2581-0855 Indexed by : Google Scholar | SINTA 4 | Garuda | Crossref | Dimensions Editor-in-Chief : Mahardi Kamalika Khusna Ali Publisher : Kadiri University The purpose of this publication is to disseminate high-quality articles that are devoted to discussing any and all elements of the most recent and noteworthy advancements in the fields of civil engineering. The focus and scope of the U Karst journal are Geotechnical, Building Structure, Bridge Structure, Airport Structure, Foundation Structure, Material Research, Management Project, Occupational Health and Safety, Transportation, Geometric Roads, Water Building, and Geographic Information System. For writers interested in submitting a script, please register online. The manuscript is received no later than one month before the issuance month, and the reviewer process is online for approximately one month. Acceptance and rejection are done online and sent by email. U Karst collaborates with National Association of Indonesian Consultants Experts (INTAKINDO), Indonesian National Association of Consultants (INKINDO), and Indonesian Civil Engineering Higher Education Consultative Body (BMPTTSSI). In addition, U Karst is supervised by Indonesian Journal Volunteers (RJI).
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Increasing the Safety Factor of Clay Shale Slopes Using Bored Pile by Limit Equilibrium Method
The clay shale slopes of the Rukoh Dam Supplementary Structure exhibit high susceptibility to weathering and shear strength reduction, which directly impacts long-term stability. This vulnerability demonstrates the importance of slope reinforcement and the need to consider the fully softened condition that represents the long-term behavior of degraded clay shale material in the field. This study aims to determine the stability of the Rukoh Dam Supplementary Structure’s clay shale slopes with bored pile reinforcement. Soil characteristic data were tested in the Laboratory to obtain shear strength. Evaluations were performed at peak and fully softened conditions using Fellenius and Plaxis LE calculations. The bored pile design was calculated based on the slope stability evaluation results and requirements to achieve a safety factor of 1.5. The results showed that slope stability was significantly reduced when the material was fully softened, with a safety factor of 0.74, thus not meeting long-term service requirements. Increasing the stability to FS 1.5 was achieved using a bored pile system with a diameter of 0.8 m and a total length of about 11 m, which can provide a moment capacity of about 364,818 kNm. These findings indicate that bored pile reinforcement can improve long-term slope stability under clay shale conditions.
Copyright (c) 2025 Mario Antoni Simanjuntak, Redha Fathki, Sriyana https://creativecommons.org/licenses/by-sa/4.0
Integrated of Pore Water Pressure, Hydraulic Gradient and Time Lag for Early Warning System at Sindang Heula Dam
Excessive pore water pressure (PWP) is a primary factor contributing to internal erosion and catastrophic failures in embankment dams, accounting for nearly 40% of dam-related incidents worldwide. Despite routine monitoring, current practices remain limited by the absence of integrated analytical frameworks that simultaneously evaluate multiple hydraulic parameters for early warning system. This study aims to design an early warning system based on PWP, hydraulic gradient, and time lag parameters. The research was conducted at Sindang Heula Dam with 1,696 daily observation data (2020–2025) from four upstream and four downstream piezometers. Linear regression analysis was employed to predict PWP at low (86.613 masl), normal (106.613 masl), and maximum (108.613 masl) reservoir water level (RWL) conditions. Hydraulic gradients were derived from upstream–downstream head differentials, while time lags were determined based on the delay between peak reservoir levels and corresponding piezometric responses. The results revealed that upstream piezometers exhibited rapid responses (7–14 days) with strong correlations RWL (R² = 0.71–0.81), while downstream piezometers show delayed responses (35–42 days) with weaker correlation RWL (R² = 0.31–0.44). Hydraulic gradients increased from 0.32 at low to 0.63 at maximum RWL, indicating intensified seepage potential. The proposed integrated framework introduces a three-tier (green–yellow–red) early warning system based on real-time RWL thresholds, thereby improving proactive risk mitigation and strengthening dam safety management.
Copyright (c) 2025 Fadel Muhammad Patra, Suharyanto, Sukamta https://creativecommons.org/licenses/by-sa/4.0
Integrating Ecocriticality and Critical Path Method for Enhancing Time Efficiency and Reduce Environmental Impact
Time efficiency and environmental responsibility are increasingly recognized as essential dimensions of modern construction management. However, most scheduling studies using the Critical Path Method (CPM) primarily focus on duration optimization, whereas the ecological impacts associated with critical activities remain overlooked. This study aims to combine CPM with an ecocriticality-based assessment of time efficiency by considering the associated ecological burden. A case study was conducted on the construction of the Integrated Laboratory and Landscape Building at the Habibie Institute of Technology in Parepare, Indonesia. Project scheduling data, cost budget documents, and material volume records were analyzed to identify critical path activities and quantify their ecological burden. Ecocriticality Index (IE) was assessed based on four weighted environmental parameters, such as material consumption, solid waste generation, reuse potential, and embodied emissions. The results show that the integration of CPM with Ecocriticality provides a more comprehensive scheduling basis by simultaneously combining time efficiency and ecological burden. Its application resulted in an optimal duration of 1 week faster and identified floor and foundation elements with the highest environmental impact and located on the critical path. This integration also produced three priority schemes that can be used as a basis for selecting intervention strategies. These findings confirm that project acceleration decisions cannot be separated from ecological assessments. The integration of CPM and Ecocriticality provides an approach that can be applied to various projects to improve time efficiency while reducing environmental impacts and supporting sustainable construction.
Copyright (c) 2025 Suriati Abd. Muin, Dr. Ir. Watono, MT, Cindy Melanie Putri, Salsabila Al-Asfahany https://creativecommons.org/licenses/by-sa/4.0
Modeling Factors Influencing Passenger Decisions on Intercity and Regional Railway Train
The dependence on private vehicles has grown significantly in the past decade, impacting travel experience quality. Transportation companies need to focus on enhancing the loyalty through exploring choice behavior. Existing research often focuses on typical service attributes, but the comparative impact with more complex variables factors remains underexplored. This study aims to identify factors influencing intercity and regional rail passenger travel decisions. This research explores sociodemographics, travel behavior, and factors affecting their mode of choice. Survey data using questionnaires were collected from 649 respondents across four intercity and five regional rail services. Logistic regression models were developed with variable selection validated using the Wald significance test and model evaluation conducted. The results indicate that intercity rail travel choices are significantly influenced by disposable income, trip purpose, and onboard comfort attributes such as air conditioning and cleanliness. In contrast, regional train choice is largely driven by factors such as occupancy rate, frequency of use, travel time reduction, and cost sensitivity. These findings confirm that intercity and regional passengers represent distinct market segments shaped by different behavioral priorities. The resulting models demonstrated strong performance, with the intercity model explaining 76.8% of the variance in choice and achieving a predictive accuracy of 82.1%, while the regional model explained 58.9% of the variance with an accuracy of 63.8%. The findings suggest that fare adjustment strategies and service development focused on air conditioning, cleanliness, and travel time can enhance ridership for both train types, thereby enhancing the overall attractiveness of the public transportation system.
Copyright (c) 2025 Audinda Virsa Leinia, Sham Sidhiq https://creativecommons.org/licenses/by-sa/4.0
Enhancement of Flexural Behavior Using Minimal Reinforced Concrete and Steel Slag as Fine Aggregate Replacement
The ductility capacity of structural elements is influenced not only by the reinforcement steel but also by the quality of the concrete material. Recent mix designs increasingly consider the incorporation of industrial by-products such as steel slag. Therefore, steel slag waste can be utilized as an alternative material in the reinforced concrete, especially for simple beam elements. This study aims to determine the effectiveness of steel slag as a fine aggregate replacement for beams as simple structural elements. The replacement ratios of steel slag were 1%, 3%, 5%, and 7% by weight of fine aggregates. The specimens included cylindrical samples for compressive strength testing and rectangular beam with 100 cm in span, for flexural testing. Beam elements conducted with two points of loading and recorded the deflection in middle and draw the crack pattern on beam element. The results revealed that the highest compressive strength, 33.24 MPa, was achieved with a 7% steel slag substitution. A higher proportion of steel slag affected the deflection behavior and internal force capacity. Initial cracking occurred at an external load of approximately 800 kg, while reinforcement yielding was observed at around 2500 kg, leading to ultimate failure. The maximum deflection of 9.25 mm was recorded for the 7% mixture, which also demonstrated the highest moment capacity. Overall, the findings confirm that partial substitution of sand with steel slag significantly enhances the flexural performance of concrete beams, thus providing a sustainable material solution.
Civil Engineering (Structure and Material)
Copyright (c) 2025 Mochamad Firmansyah Sofianto, Meity Wulandari, Yanuar Bayu Nugroho, Muhammad Titho Heryanto https://creativecommons.org/licenses/by-sa/4.0
The Efficacy of Type F Fly Ash from Paiton Power Plant on the Compressive Strength of Concrete
Portland cement is the primary binder in concrete and plays a crucial role in defining its structural performance. However, its production contributes approximately 7% of global carbon dioxide emissions, necessitating sustainable alternative materials. One potential material is Type F fly ash derived from coal combustion waste in steam power plants. This study aims to evaluate the effectiveness of Type F fly ash from the Paiton Power Plant as a sustainable cement replacement material in concrete based on compressive strength performance. Fly ash was activated using an alkaline solution consisting of NaOH and Na₂SiO₃ with a ratio of 1:2.5, where the NaOH concentration was maintained at 10 M. Two water–cement ratios (W/C) of 0.45 and 0.55 were employed to investigate their influence on workability and compressive strength. Cylindrical specimens were tested at 28 days with fly ash replacement levels of 0%, 80%, 90%, and 100% by weight of cement. The results indicate that increasing fly ash content significantly enhances compressive strength. The optimal performance was achieved with 100% fly ash replacement, yielding a compressive strength of 48.48 MPa or an increase of 102.4% compared to conventional concrete. This performance is attributed to the high silica content of Type F fly ash, which promotes the formation of dense N-A-S-H gel through alkaline activation, resulting in a more compact and less porous microstructure. These findings demonstrate that Type F fly ash from the Paiton Power Plant can effectively function as a primary binder, offering a sustainable alternative for high-performance concrete production.
Copyright (c) 2025 Thesalonika Octaviana Wahyudi, Wahyu Kartini, Nia Dwi Puspitasari https://creativecommons.org/licenses/by-sa/4.0
Statistical Validation of 2% Lignosulfonate as a Sustainable Stabilizer for Expansive Clay
Expansive clay soils undergo volumetric changes due to fluctuations in moisture content, which can cause structural damage to foundations, pavements, and embankments. Traditional stabilization methods, such as cement and lime, are effective but have a significant environmental impact, highlighting the need for more environmentally friendly alternatives. Lignosulfonate (LS), an organic stabilizer derived from industrial by-products, offers a more sustainable approach to improving soil strength and stability. This study evaluates the effect of 2% lignosulfonate on the unconfined compressive strength (UCS) of expansive clays. The research method involved mixing LS at 2% of the dry weight of the soil into the expansive clay (CL-ML) and conducting UCS tests on three untreated (control) samples and six treated samples. Statistical analysis was used to assess the significance of the differences between the two groups. Results show that the UCS increased from 236.29 kPa in the control group to 291.49 kPa in the treated group, reflecting a 23.37% improvement. Poisson's ratio decreased from 0.300 to 0.200, indicating reduced lateral deformation and enhanced soil stiffness, which improves the bearing capacity and stability of structures built on it. The UCS values ​​were observed to be consistent supported by low standard deviation. The study highlights the critical role of adequate sample replication and control over operational variables such as moisture content, compaction, and LS dispersion to ensure reliable and reproducible stabilization outcomes. This study strengthens the empirical basis for the application of LS as a sustainable and environmentally friendly stabilizer for expansive clays.
Copyright (c) 2025 Arif Rivianto, Agata Iwan Candra, Fauzie Nursandah, Imam Mustofa https://creativecommons.org/licenses/by-sa/4.0
Satisfaction and Determinants of the Decision to Switch from Private Vehicles to Commuter Trains in Merak–Rangkasbitung
Urban population growth has had an impact on traffic congestion. Although public infrastructure is available, public preference for private vehicles remains high. This occurs on the Merak-Rangkasbitung route which is served by the train. The gap between service availability and user preferences indicates the need to study mode selection behavior and the factors that influence it. This study aims to analyze motorcycle and car users' tendency to shift their transportation modes from private vehicles to the train service on the Merak- rangkasbitung route. A quantitative approach was carried out using a questionnaire survey method on 300 respondents using a dual-stratum sampling technique. The analysis used the Importance Performance Analysis (IPA), Customer Satisfaction Index (CSI), and Chi-Square test. The IPA results showed a service suitability value of 86.57%, while CSI showed a satisfaction level of 72.86% (satisfied category). The Chi-Square test results identified that the factors influencing the transportation mode choice differed between segments. For motorcycle users, it was influenced by age, car ownership, and reason for travel, while car users were influenced by occupation, travel costs, reasons and purposes of travel. These findings emphasize the importance of a policy approach based on user segmentation and strengthening integration between modes to improve the effectiveness of train services. With an adaptive service strategy and targeted incentive policies, the transformation towards sustainable urban mobility can be realized.
Copyright (c) 2025 Muhammad Oka Mahendra, Muhammad Djuneydi https://creativecommons.org/licenses/by-sa/4.0
Optimization System Irrigation Using Linear Programs in the D.I. Delta Brantas Region Sidoarjo (Case Study: Dungus Intake)
Global food security is facing challenges due to climate change and increasing water needs for agriculture. One area experiencing these problems is the Dungus intake irrigation area in Sidoarjo Regency, which faces water management due to land use changes and uncertainty of water availability. As a result, the efficiency of water distribution decreases, and agricultural productivity is disrupted, so efforts are needed to optimize the irrigation system. This study aims to optimize the irrigation system in the Dungus Intake Irrigation Area to increase the efficiency of water distribution. This effort is carried out by determining the optimal planting pattern and irrigation water allocation using the linear programming method. This method is applied by considering the mainstay discharge of the Dungus intake, crop irrigation needs, and economic benefits from various cropping pattern scenarios. The results show that the mainstay discharge ranges from 0,479–0,754 m³/sec with an allocation discharge of 2.604 m³/sec. The optimal alternative cropping pattern 3, with a land area of ​​1.890 ha, consisting of rice, corn, and shallots in three planting seasons, produces a maximum profit of Rp 242.087.200.000 per year. This study can develop an irrigation optimization model based on hydrology and economics that can improve the efficiency of water distribution. This irrigation optimization model provides a reference for irrigation managers and farmers in designing better water distribution strategies that can increase agricultural yields and economic profits through more appropriate water allocation and optimal land use.
Copyright (c) 2025 Khoirotun Nisa, Danayanti Azmi Dewi Nusantara https://creativecommons.org/licenses/by-sa/4.0
Evaluation of Seawater Intrusion and Impact on Infrastructure in the Coastal Area of ​​North Surabaya
Several wells of coastal residents at North Surabaya experienced changes in odor, taste, and color indicating seawater intrusion. This phenomenon can cause an increase in groundwater salinity, which impacts clean water quality, public health, and infrastructure resilience. Therefore, it is important to evaluate seawater intrusion in the area. This study aims to evaluate the level of seawater intrusion, determine the distribution pattern of intrusion, and identify high-risk zones for seawater intrusion and the level of infrastructure vulnerability to corrosion. The methods used include analysis of physical and chemical parameters of groundwater, intrusion assessment using the Revelle Index and Electrical Conductivity (EC), and mapping based on Geographic Information System (GIS) to determine the distribution pattern of intrusion. The laboratory's well water sample testing showed an average EC score approaching 1500 μS/cm, and the R-value was far above 1. It meant that well water in North Surabaya has been facing seawater intrusion from medium to high levels. It also predicted the distance of seawater intrusion is about 2,5 km from the coastline and has the most significant risk of infrastructure degradation due to corrosion. Seawater intrusion in Surabaya is caused by geographical proximity to the sea, aquifers' hydrodynamic factors, and high groundwater exploitation. The results of this study contribute to providing a seawater intrusion risk map that can be a reference for the government and policymakers in developing mitigation strategies and groundwater management policies to reduce the impact of seawater intrusion.
Copyright (c) 2025 Soebagio, Utari Kathulistiani, Johan Pahing, Konstantinus Datom https://creativecommons.org/licenses/by-sa/4.0
Landslide Mechanisms in the Cisumdawu Toll Road through a Geoforensics Approach to Increase Slope Stability
Landslides are a significant threat to infrastructure in tropical regions like Indonesia, especially in projects that cross volcanic slopes. A significant case occurred on the Cisumdawu Toll Road Section 2, triggered by high rainfall and water-saturated young volcanic soil. Given the complexity of such failures, comprehensive investigations are crucial. This study aims to analyze the causes and mechanisms of landslides in the Ciherang Village, specifically at STA 19 KM 65 using a geoforensics approach. This approach involves field investigations to collect geotechnical and geophysical data such as boring logs, SPT, pressure meters, inclinometers, and geoelectric resistivity testing. These were used to reconstruct subsurface conditions before failure. Numerical modeling was then performed with variations in groundwater level (GWL) and K₀ to simulate slope stability and identify failure triggers. The results show that landslides was translational, occurring in the transition zone between sandy silt (tuff) and weathered tuff breccia layers at depths of 30–35 meters, where differences in permeability made the zone vulnerable. The decrease in GWL significantly improved slope stability, increasing the safety factor to 1.435, while K₀ variation had a lesser impact. A combination of bored piles, ground anchors, soil nailing, and slope regrading effectively stabilized the slopes. These findings contribute to a better understanding of the mechanisms and causes of landslides so that mitigation strategies can be more targeted to increase slope stability.
Copyright (c) 2024 Adhystira Mardjuni, Paulus Pramono Rahardjo, Fahmi Aldiamar https://creativecommons.org/licenses/by-sa/4.0
Consistency of Compressive Strength in Concrete with 10% Rice Husk Ash Substitution
Using rice husk ash (RHA) in concrete technology represents a significant innovation in promoting sustainability. The pozzolanic properties of RHA enhance concrete quality through microstructural refinement while mitigating environmental impacts. However, replacing 10% of cement with RHA has inconsistent effects on compressive strength. Such variability may limit the broader application of RHA in structural concrete due to uncertainties in performance prediction, quality assurance, and design safety. While some studies report strength improvements, others note reductions often attributed to limited samples size, material inconsistencies, and variations in mixing or curing processes. This study aims to statistically validate the consistency of compressive strength in concrete with 10% RHA substitution by increasing the sample size and controlling key variables. Nine specimens per test condition were evaluated using a water-cement ratio of 0.53, submersion curing and ASTM C39 testing standards. Compressive strength assessment was conducted at 7 days. The result show a 7.54% increase in compressive strength, from 22.71 MPa to 24.42 MPa, with a coefficient of variation (CV) of 2.26%, well below the 10% threshold. In contrast, earlier studies with smaller sample sizes reported CVs as high as 42.65%, indicating greater statistical variability. This improvement is attributed to the increased sample size, material quality control, and uniform mixing, which ensured homogeneous RHA distribution and optimized pozzolanic reactions. By applying a controlled-variable approach and increasing the sample size, this study addresses prior inconsistencies and reinforces the validity of RHA as a viable cement substitute in concrete.
Copyright (c) 2025 Salman Alfaridh Pasya, Zendy Bima Mahardana, Imam Mustofa, Agata Iwan Candra https://creativecommons.org/licenses/by-sa/4.0
Performance Evaluation of Freight Train Wooden Sleepers on the BH 77 Tegineneng Bridge
Rail transport is very important in supporting human mobility and distribution of goods for heavy loads such as coal. The BH 77 Tegineneng Bridge in Sumatra is a critical infrastructure that supports coal transportation. In its structural components, wooden sleepers are used on this bridge. The wooden sleepers used must withstand dynamic, shock, lateral, and longitudinal loads. This is to ensure the stability and operational safety of the bridge. This study aims to evaluate the performance of wooden sleepers on the BH 77 Tegineneng Bridge. A case study approach was used with field data on axle loads, including static and dynamic loads, collected and analyzed to determine the load distribution and structural response. The results show that the dynamic load with a Dynamic Amplification Factor of 1.86, coupled with a shock load reaching 56,784 kN, exerts significant stress on the sleepers. The wooden sleepers effectively absorb dynamic forces, distribute the load evenly, and demonstrate resilience under repeated loading cycles, with a maximum bearing load of 189.28 kN. These findings emphasize the suitability of wood as a sleeper material due to its elasticity and damping properties, which offers a durable and efficient railway infrastructure. This study contributes to demonstrating the characteristics of wooden sleepers as a basis for material selection in freight railway systems.
Copyright (c) 2024 Nurmagita Pamursari, Hadyan Arifin Bustam, Meutia Nadya Karunia, Ananda Agneshia Putri https://creativecommons.org/licenses/by-sa/4.0
Flood Risk Analysis for the Construction of the Patimban Port Access Toll Road
In recent decades, the risk of flooding in the Cipunagara River area has increased due to global climate change causing more extreme rainfall patterns. The planned construction of the Patimban Port Access Toll Road has a strategic role in supporting national logistics connectivity. However, the geographical location of the planned toll road in the lowlands near the Cipunagara River poses a significant risk to the sustainability of the infrastructure. This study aims to analyze the risk of flooding in the Cipunagara River and its impact on the design of the toll road. Hydrological analysis was carried out using rainfall data from eight observation stations for the period 2012–2021. Analysis of frequency distribution, rainfall intensity and the Soil Conservation Services (SCS) Unit Hydrograph method was carried out to calculate peak flood discharge. Modeling was carried out using Surface Water Modeling System (SMS) software. The results of the study indicate that the Cipunagara River Basin (DAS) has high rainfall variability with the potential for extreme rainfall in large return periods. The peak discharge of the 100-year return period is 1003.582 m³/second, indicating the risk of extreme flooding because it exceeds the river capacity of 309.31 m³/second. The results of flood modeling show that the flood water level in the 100-year return period reaches +8,908 meters, which confirms the need for a minimum toll road infrastructure elevation of +9,908 meters to meet the vertical clearance standard. These findings provide a significant contribution to the planning of toll road infrastructure that is more resilient to flood risks, supports operational sustainability, and reduces potential economic losses.
Copyright (c) 2024 Agung Abdullah Dwi Noviantoro, Fauzia Mulyawati, Rully Savitri Nurvita https://creativecommons.org/licenses/by-sa/4.0
Non-Destructive Test and Numerical Approach for Tailrace Safety Evaluation of Ir. H. Djuanda Dam
Dam Ir. H. Djuanda is one of the important infrastructures in managing water resources in Indonesia, with strategic functions such as flood control, irrigation, hydroelectric power plants (PLTA), and raw water supply. The lower channel (tailrace) plays a crucial role in supporting the efficiency of the dam's hydraulic system. However, previous inspections revealed erosion and exposed aggregate in the tailrace concrete layer which could threaten the stability of the structure. This research aims to evaluate the condition of the tailrace structure of Dam Ir. H. Djuanda. An evaluation was carried out by integrating the NDT method using Schmidt Hammer and numerical simulation via Plaxis 2D software. The Schmidt Hammer test data gives an average concrete quality value of 37.47 MPa, while the Plaxis 2D simulation shows that the Cartesian stress ( , and ) on the structure is still within safe limits. The simulation results also show a safety factor value of 1.795, which meets the structural safety criteria. These findings indicate that the tailrace concrete was designed with a high safety factor, so that it can withstand hydrostatic loads and ground pressure even though it has been in operation for more than five decades. This research shows that the combination of NDT and numerical simulation is an effective method for evaluating structural conditions without damaging the material. This approach can be adopted to inspect and maintain similar infrastructure to ensure long-term operational stability and sustainability.
Copyright (c) 2024 Vivik Arti Damayanti, Fauzia Mulyawati https://creativecommons.org/licenses/by-sa/4.0
Optimization of Column Stirrup Selection (Square and Spiral) for Earthquake Resistance of 10-Storey Buildings
Earthquake-resistant building design is very important, especially in earthquake-prone areas such as Indonesia. The shape of the column cross-section and the ties' configuration greatly affect the building's stiffness when exposed to earthquake loads. Therefore, knowing the optimal tie configuration to increase earthquake resistance is important. This study aims to analyze the structural performance of a 10-story building using columns with spiral stirrups and square stirrups. Model 1 uses columns with square stirrups, Model 2 uses spiral stirrups, and Model 3 is a combination of both. Simulations were conducted using ETABS 18 software, where the base shear force, displacement, and inter-story drift as well as the collapse pattern and performance level of the structure were analyzed using the pushover analysis method to determine the effect of each configuration on the stiffness and ductility of the columns when receiving earthquake loads. Analysis of Variance (ANOVA) analysis was carried out to ensure that the differences in seismic performance between the three models were significantly validated. The results show that Model 2 has lower displacement and base shear force values and smaller inter-story drift than the other models, and the collapse pattern and structural performance level of Model 2 are also smaller than the other models. The ANOVA results showed no significant difference between the models. This is because the differences in displacement and drift values are relatively small. These findings can provide guidance for selecting the most efficient column tie configuration for resisting earthquake loads and achieving safety levels.
Copyright (c) 2024 Syahla Khairunnisa, Amalia, Jonathan Saputra https://creativecommons.org/licenses/by-sa/4.0
Comparative Analysis of Analytical and Numerical Methods on the Safety Factor of Retaining Walls
The stability of retaining walls is a major concern in geotechnical design, especially in landslide-prone areas such as Indonesia. A comprehensive analysis requires an in-depth understanding of the failure mechanism and the factors that influence its stability. Therefore, a comparison of various analytical and numerical methods in the stability of retaining walls is an important step to determine the most effective approach. The data were collected through laboratory tests and field investigations of soil properties. The retaining wall design was modeled using Plaxis and Midas software. The analysis focused on comparing the safety factor values obtained from the Rankine method with those derived from Plaxis and Midas simulations. The results show that Rankine provides a high safety factor, namely 2.54 for rotation and 2.447 for shear. Rankine, although simple, remains relevant for uniform soil conditions. Plaxis can provide more detailed deformation and pressure distribution predictions with a safety factor reaching 2.95 in the third excavation stage. Meanwhile, Midas provides a comprehensive analysis of axial force and bending moment with a safety factor value that tends to be smaller. This study provides new insights into how each method can be used effectively for different technical conditions, and provides practical guidelines for geotechnical planners in choosing the appropriate analysis method to improve the efficiency and safety of retaining wall design.
Copyright (c) 2024 Aulia Akbar, Tommy Prasetyo Wibowo, Tika Ermita Wulandari https://creativecommons.org/licenses/by-sa/4.0
Enhanced Accuracy in Construction Cost Estimates Using BIM
The Indonesian construction industry is experiencing rapid growth and increasing complexity. If done using conventional methods, this process often involves multiple manual stages that are prone to errors and inconsistencies thus requiring significant time and resources. Building Information Modeling (BIM) is a technology that provides solutions in the volume and cost estimation process. However, there have been few studies that verify the output of BIM with control calculations. This study aims to compare the volume and cost outputs from BIM with those from the Bill of Quantities (BoQ) by re-evaluating volumes identified as clashes and verifying the actual costs. Data on plan drawings, BoQ, and planned costs were obtained from a public service center building project with modeling conducted using Autodesk Revit and Naviswork. Manual volume calculations and actual cost data were used for comparison. The results showed that the BIM cost estimate was highly accurate, with a minimal difference of IDR 1,249,901.21 (0.0032%) compared to the real cost. In contrast, the BoQ estimate was higher by IDR 1,022,985,135.58 (2.63%) compared to the real cost and IDR 1,024,235,036.79 (2.57%) higher than BIM. This is because in volume calculations, BIM software has proven to be more detailed and accurate in calculating the volume of all work items and is able to eliminate human error factors. The results of this study contribute to the construction industry by highlighting the significant advantages of using BIM software that can increase efficiency and reduce the risk of calculation errors.
Copyright (c) 2024 I Komang Krisna Aditya, Erick Triswandana, Ni Komang Ayu Agustini https://creativecommons.org/licenses/by-sa/4.0
Simulation-Based Exploration with Energyplus as an Energy Efficiency Strategy
In countries with tropical or subtropical climates, such as Indonesia, the use of air conditioning is becoming increasingly important for comfort and productivity. However, high energy use in air conditioning systems has significant environmental and economic impacts, including increased greenhouse gas emissions and high operational costs. This research aims to analyze the Energy Consumption Index (ECI) in the Joint Lecture Building, State University of Malang using EnergyPlus software simulation. Research data consists of building data, weather data, building construction data, operating schedules, equipment specifications, and energy usage data. Furthermore, the data analysis technique used ECI calculations based on EnergyPlus software simulation. The research results show that based on the Energy Consumption Index value it is 201,943 kWh/m2/year, but with a savings scenario it becomes 161,964 kWh/m2/year (an increase of 19,797%) so it is classified as efficient. The energy-saving scenario implemented is to replace the Constant Air Volume (CAV) air conditioning system with Variable Air Volume (VAV) and the types of luminaires that were originally fluorescent will be replaced with Light Emitting Diodes (LEDs). The comparison results obtained an energy-saving value of 19,797%. The research results show that using VAV and LEDs technology can increase energy efficiency in the Joint Lecture Building, State University of Malang. The scenario attempts to reduce environmental impact through energy efficiency in commercial buildings and shows that the EnergyPlus simulation method is an effective approach for designing energy savings strategies.
Copyright (c) 2024 Raihan Madani, Antelas Eka Winahyo https://creativecommons.org/licenses/by-sa/4.0
Comparison of Predictive Modeling Concrete Compressive Strength with Machine Learning Approaches
Accurately predicting concrete compressive strength is fundamental for optimizing mix designs, ensuring structural integrity, and advancing sustainable construction practices. Increased demands for safer, more durable infrastructure necessitate effective predictive concrete compressive strength models. This research aims to compare the effectiveness of six machine learning models such as Linear Regression, Random Forest, Support Vector Regression (SVR), K-Nearest Neighbors (KNN), Gradient Boosting, and XGBoost to predict concrete compressive strength. Used a dataset of 1030 instances with varying mixture compositions, conducted extensive exploratory data analysis, and applied feature engineering and data scaling to enhance model performance. Assessments were performed with a 5-fold cross-validation approach with the R-squared (R²) metric. In addition, the SHAP value is used to understand the influence of each feature on the compressive strength results. The results revealed that XGBoost significantly outperformed other models, achieving an average R² value of 0.9178 with a standard deviation of 0.0296. Notably, Random Forest and Gradient Boosting also demonstrated robust capabilities. Based on our experiment, these models effectively predicted compressive strengths close to actual measured values, confirming their practical applicability in civil engineering. SHAP values provided insights into the significant impact of age and cement quantity on model outputs. These results highlight the advanced ensemble methods' effectiveness in concrete compressive strength prediction and underscore the importance of feature engineering in enhancing model accuracy.
Copyright (c) 2024 Gregorius Airlangga https://creativecommons.org/licenses/by-sa/4.0
Increasing Compressive Strength of Self Compacting Concrete with MasterGlenium and MasterSure
The growth in development complexity demands innovation in the construction industry. Self-compacting concrete (SCC) can flow and fill mold cavities without additional vibration, offering an efficient solution for structures with complex shapes or tight spaces. In addition, SCC can speed up bonding and simplify workability by adding MasterGlenium and MasterSure superplasticizers. However, its use is limited due to a lack of understanding of the optimal composition of the mixture. The research aims to determine the effect of adding MasterGlenium and Maste Sure in the concrete mixture on the compressive strength of concrete. Experimental research was conducted with a mixture of MasterGlenium additives at 0.25%, 0,30%, 0,35%, 0.40%, and MasterSure 0.30% of the total binder. Slump and compressive strength tests of concrete are carried out to determine workability and quality performance. The research results showed that the optimal concrete mix with the addition of MasterGlenium 0.35% and MasterSure 0.30% was 25.39 Mpa, higher than Normal concrete 15.21 Mpa. The slump test results confirm that the concrete is classified as SCC. This shows the importance of the composition of MasterGlenium and MasterSure superplasticizers on the compressive strength of SCC concrete. So, the results of this research can be used to improve the quality of concrete structure projects.
Copyright (c) 2024 Redyka Sefiyanti, Zendy Bima Mahardana, Apriliya Laily Rahmawati, Nadiya Husna, Zaizafun Zakiya, Hafiizh Naufalanto, Tegar Bhakti Yuantono https://creativecommons.org/licenses/by-sa/4.0
Unveiling Subsurface Characteristics of Cliff Land in Sibang, Bali Through Geoelectric Investigation
The unique geological formations and environmental dynamics of cliffs underscore the significance of comprehending soil composition and structural integrity for diverse applications, such as infrastructure development and environmental conservation. Geoelectrical needs to be done because the underground geological conditions of the cliff must be researched and assessed first before construction is carried out so that construction failure does not occur. This research aims to reveal the subsurface characteristics of cliff soil in Sibang, Bali through geoelectrical investigation. This research was conducted by evaluating the soil condition in the field using the geoelectric resistivity method to the ability of a material to inhibit the flow of electric current and geological regional theories. At points BL-01 and BL-04, there is a significant potential risk of landslides due to the thick layer of breccia, especially during high rainfall or additional loads in the area. Point BL-02 also has a potential risk of landslides due to the thick layer of basalt and wet sand. Meanwhile, points BL-03 and BL-05 are more ideal locations for construction because they consist of relatively stable hard rock. Point BL-06 outside the development zone has layers of gravel, weathered tuffa and andesite which could be considered for future development. Thus, a deep understanding of the geological characteristics of each point is important to manage risks and ensure the safety and sustainability of construction projects in that area.
Copyright (c) 2024 Nur Ayu Diana, Ganeca Efa Mareta https://creativecommons.org/licenses/by-sa/4.0
Increasing Unconfined Compressive Strength of Soft Clay Stabilized with Coir Fiber and Bagasse Ash Mix
Increasing coir fiber and bagasse ash waste can cause environmental degradation. Utilization of this waste in construction work is still rarely done. Coir fiber is a natural material with the highest coefficient of friction and tensile strength. Bagasse ash has a high silica content and is suitable for use as pozzolan. Soil stabilization with a combination of both is expected to improve the geotechnical properties of soft soil. This research aims to analyze the unconfined compressive strength (UCS) and secant modulus of soft clay stabilized with coir fiber-bagasse ash mix. Coir fiber as much as 0.75% and ash with varying contents: 0%, 2%, 4%, 6%, 8%, and 10% of the total weight of the mixture. The specimens were cured for 28 days. UCS tests were conducted according to ASTM D2166-16 with the axial stress and strain relationship curve results to determine the UCS and secant modulus. The results showed that the UCS value and secant modulus value increased along with increasing bagasse ash content. The maximum value was achieved at 8% ash variation with a UCS value of 472.45 kPa (an increase of 382% from a soil-coir fiber mix) and a secant modulus value of 21.94 MPa (an increase of 571% from a mixture of soil and coir fiber). The research results show that this mixed soil is classified as hard soil, which can withstand high loads. It is hoped that the results of this research can become a reference for stabilizing soft soil in the field.
Copyright (c) 2024 Anita Widianti, Svastika Ariana Sundi, Anita Rahmawati, Dian Eksana Wibowo https://creativecommons.org/licenses/by-sa/4.0
Abrams’ Law Formulation for Blended Cement Paste Incorporated with Ground Ferronickel Slag
Ground ferronickel slag (GFS) is a form of an industrial waste by-product generated during the smelting process of nickel ore that has been crushed and ground into fine powder. GFS is a pozzolanic substance that may be employed as an environmentally beneficial binding agent when blended with Portland cement. This research aims to apply the Abrams Law formulation to blended cement combined with GFS. GFS was utilized as a Portland cement composite (PCC) replacement at varying percentages of 0, 10, 20, 30, 40, and 50 wt.%. The blended cement paste incorporated with GFS was tested at three water to cementitious material ratio (w/cm) levels of 0.4, 0.5, and 0.6. After samples have been made, a compressive strength test is carried out. The research results showed that at 28 days, the optimum amount of GFS was found in the percentage of 20 wt.% induced the compressive strength by 40.41 MPa with a w/cm of 0.4. The equations based on Abrams’ Law have been proposed for estimating the correlation of 28-day compressive strength with w/cm in the range from 0.4 to 0.6. In addition, the hardened densities of binary blended cement paste were investigated. It was found that the density decreased with an increase of w/cm. The proposed equations provide the beneficial interpretation for estimating the compressive strength of blended cement paste based on the w/cm..
Copyright (c) 2024 Herry Suryadi Djayaprabha, Ashila Hasya Fatharani https://creativecommons.org/licenses/by-sa/4.0
Finite Elements Method Investigation of Plates with Varied Support and Opening for Design Optimization
Plates have an important function in supporting the structural load above them. One important aspect of plate design is the design of the openings or holes. These openings can be needed for various purposes, such as pipe installation, ventilation, and ducts. If the plate openings are not designed carefully, it will cause serious problems such as excessive deflection. This increases the risk of structural accidents and ultimately threatens the safety of building users. This study aims to determine the effect of plates with different types of supports and opening models with 3D modeling. Quantitative descriptive research using the finite element method was used. There are 16 models with different support types (simply and fixed) and opening models (rectangular, square and circular). From the modeling, the deformation and stress values that occur will be obtained. Comparative analysis is carried out to obtain the best support and opening types. The research results show that the increase in stress concentration tends to be higher in rectangular openings, while in square and circular openings, it is smaller than in plates without openings. Circular shapes tend to have high deformation values. Meanwhile, the square shape has the smallest value compared to all models. Simply support has greater stress in rectangular and circular openings. 4-sided fixed support is the best choice because it has the smallest stress and deformation values. Through these results, it is possible to optimize the design of appropriate types of supports and openings to reduce excess stress and improve overall structural performance.
Copyright (c) 2023 Faqih Ma arif, Zhengguo Gao, Eva Fatimah, Putri Nabila, Anna Rizti Pertiwi, Apri Ana Puji Astuti, Afif Fadhlih Rahardika, Azizah Nur Rohmah https://creativecommons.org/licenses/by-sa/4.0
Proposed Speedy Moisture Test Calibration Chart on Indonesian Road Embankments
Embankment construction is generally carried out using borrow materials. The water content of embankment material significantly affects the compaction quality. Measuring water content in the field typically uses a speedy moisture test (SMT) because the process is simple, and the result is obtained immediately. The accuracy level of the SMT is relatively high. However, it still needs to be corrected using a calibration chart for a more precise measurement. This research aims to determine the accuracy of the SMT tool compared to the standard oven-dry method, especially on borrow materials in East Java. The experimental method was used with soil samples from Pasuruan and Mojokerto borrow. Standard index properties tests and soil compaction tests were conducted to determine soil type and obtain optimum water content. The water content varies in several levels and is measured using SMT and oven-dry methods. The regression was performed to make a correlation, while RMSE and simple paired T-test were conducted to investigate the accuracy level of the correlation chart from this research, respectively. It was found that the soil samples used met the requirements as embankment soil (SW and SM). The proposed calibration chart is presented with the SMT-corrected water content equation (WSMT-corrected = 0.9815WSMT – 1.4323 ). This equation has a coefficient of determination (R2) equal to 0.95, which mean a very strong relationship. The proposed calibration chart performs well according to RMSE, which is equal to 2.41 and paired T-test result. This proposed calibration chart can be widely used in road embankment practice in Indonesia.
Copyright (c) 2023 Soebagio Soebagio, Danang Setiya Raharja, Utari Khatulistiani https://creativecommons.org/licenses/by-sa/4.0
Efficiency of Using PERI Formwork in Low-Rise Buildings Project
Concrete construction is still the main choice because of its high strength, durability, and ability to withstand heavy loads. In reinforced concrete construction, formwork is a fairly important element. Formwork significantly impacts the efficiency of construction implementation. Formwork innovation has found PERI formwork to be a solution that many consider more efficient. Efficient use of PERI formwork is an important focus to increase productivity, minimize time, and reduce construction costs. This research aims to analyze the quality, cost, and implementation time of PERI formwork compared to conventional formwork in 2-story buildings. Quantitative methods are used to evaluate quality (strength of bending, safe deflection, and strength of the shear) using SAP 2000, implementation time using Microsoft Project, and project costs using unit price analysis. The research results show that using the PERI formwork system can provide various efficiencies in formwork work. PERI formwork has been proven stronger in withstanding loads and meets current load regulations. It can save project implementation time by up to 21 working days (24.7%) with a cost reduction of 4.72%. This is because the installation cycle is faster, which can increase productivity and reduce costs. So, using the PERI system formwork has proven efficient and can be the best choice for low-rise building construction projects.
Copyright (c) 2023 Monika Natalia, Hendra Alexander, Merley Misriani, Muhammad Zaqharia, Dani Kurniawan https://creativecommons.org/licenses/by-sa/4.0
Investigation and Slope Improvement of Landslides on Bodor River Slopes
The Bodor River is an important source of rice irrigation because most of the population works in the agricultural sector. The slopes of the Bodor River have experienced landslides, causing a major negative impact on the community. Many studies state that soil type, consistency, and friction angle influence slope failure. However, the relationship between soil characteristics and landslides on slopes, especially on the Bodor River, has not been studied. This research aims to identify soil characteristics and their influence on landslides on the slopes of the Bodor River, along with recommendations for improvement. The soil was taken after a landslide occurred at a depth of 80 cm for a sieve gradation test, Atterberg limit test, direct shear test, and slope stability analysis using the Cullman method. The research results show that the SW-SM soil type on the slopes of the Bodor River is highly vulnerable to landslides. A steep slope of 50° and a low soil friction angle between 1.38 and 14.11 have less than one safety factor. Changes in soil conditions, such as increased water content, contribute to a higher risk of landslides. Therefore, strengthening the slope is necessary, with the recommendation to increase the slope to 34.5° so that the slope safety factor increases by 73%. The results of this research provide an overview of the relationship between geotechnical soil parameters that influence slope failure in river areas and recommendations for slope improvement to prevent future collapse.
Copyright (c) 2023 Ma’rifatul Mumayyizah, Agata Iwan Candra, Alfina Iskindaria, Farikhatul Mufaidah, M. Risjad Aldiansyah https://creativecommons.org/licenses/by-sa/4.0
RETRACTED: Construction Schedule Management for Densely Populated Areas Using CPM-Crashing
This article has been retracted: please see U Karst Policy on Article Withdrawal. (https://ojs.unik-kediri.ac.id/index.php/ukarst/article-retraction) This article has been retracted at the request of the Editor-in-Chief. This decision was taken because it was discovered that almost the same article had been published earlier on October 31, 2023, in the Jurnal Teknik Sipil: Rancang Bangun (https://ejournal.um-sorong.ac.id/index.php/rancangbangun/article/view/2632). The author was identified as having made multiple submissions, namely submitting a manuscript in the U Karst Journal on July 3, 2023, and also submitting almost the same manuscript in the Jurnal Teknik Sipil: Rancang Bangun on August 24, 2023. The Editors deplore the practice of simultaneous multiple submissions of papers to different journals. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter, and we apologize to the journal readers that this was not detected during the submission process.
Copyright (c) 2023 Tsulis Iq'bal Khairul Amar, Fresti Febria Astuti, Vivi Tri Wulandari https://creativecommons.org/licenses/by-sa/4.0
Evaluating Differences in Foundation Depth Planning and Implementation for Building Structure Safety
Kediri has been named the Most Sustainable City. To support this, Kadiri University also contributed by building lecture buildings. In its implementation, there is a difference in the depth of the foundation from the initial plan. This causes the need for evaluation to ensure the safety of the building structure. This research aims to identify (Cone Penetration Test) CPT distances, depth differences, negative skin friction, settlement, and empirical bearing capacity calculations on the safety of building structures on sandy soil. The direct observation method was used to obtain data. The analysis includes a comparison of depth, negative skin friction values, settlement, and bearing capacity. The research results show that the average CPT distance is 18.22 m, which can result in inaccurate CPT data because differences in soil structure can occur. A depth difference of 22% from the plan can be considered safe for the structure. This is validated by a field settlement of 2 mm lower than the maximum settlement limit and a Negative skin friction value of 0, indicating no additional settlement. These parameters indicate that the structure is safe. The modified Meyerhoff and Trofimankove methods are suitable for planning foundations with sandy soil because they can meet the load received. This research can add empirical evidence in evaluating structural safety for different depths of foundation planning and implementation in sandy soil-based projects, as well as reducing the potential risk of structural failure in the long term.
Copyright (c) 2023 Sheila Ananda Putri Pertiwi, Agata Iwan Candra, Rama Putra Nugraha, Tiara Sherlyta Sari, Wiwit Mely Yanti Jannah, M. Faisol Firmansyah, Mohammad Agus Fajar Wibowo https://creativecommons.org/licenses/by-sa/4.0