Journal of Civil Engineering

The Impact Of Tide On Flooding In The The Kali Welang, Pasuruan, East Java

Ainun M. M. Gasa — 2025-12-08

Flooding in the Welang River, Pasuruan, East Java, is a recurrent problem influenced by multiple factors, primarily high-intensity rainfall and tidal fluctuations. This study aims to quantitatively assess the impact of tidal conditions—including extreme events such as supermoons—on the spatial extent and depth of flood inundation in the downstream segment of the Welang River. Utilizing hydrologic (HEC-HMS) and hydraulic (HEC-RAS) modeling, the research estimates design flood discharges for multiple return periods and simulates three scenarios: (1) flood discharge without tidal influence, (2) flood discharge under normal tidal conditions, and (3) flood discharge during tidal peaks associated with a supermoon. The results indicate that the 100-year design discharge reaches 409.7 m³/s. Tidal conditions significantly amplify both the extent and depth of inundation, with the greatest increase in flood coverage observed at the 2-year return period (85.88%). Furthermore, the supermoon phenomenon intensifies flooding, producing the highest additional inundation extent during the 5-year return period (34.81%).

Erosion and Sedimentation Modeling Using Delft3D in the Manikin Estuary, Kupang, East Nusa Tenggara

Alexandro T Kolo — 2025-12-08

The sedimentation and erosion of Manikin Estuary is analysed using numerical model DELFT3D. The model simulates the influence of river flow and coastal wave to induce the transport of sediment. The river flow is obtained from automatic water level data and suspended sediment is measured on site. The wave is hindcasted using spectral wave model SWAN with forcing from ERA 5 Reanalysis Data. The model is calibrated by comparing the coastline change from the model and satellite imagery. The simulation scenarios consider the combination of river discharge and waves condition in east season and west season. The simulation shows in the west season the dominant influence from high waves produces considerable erosion and sedimentation in the estuary and coastal areas, while high river discharge during the wet season has more influence on sedimentation and erosion in the river. Meanwhile, in the east season, the dominant influence from waves results in sedimentation and erosion that predominantly occurs in coastal areas even though the waves are relatively lower than the west season.

Erosion Analysis With Geographic Information System On Watershed Area of Tapin Dam, South Kalimantan

Yanuar A Pratama — 2025-12-08

Population growth in the Tapin Dam watershed area causes increasing land needs and changes in land function. Changes in land use and high rainfall can cause erosion, which causes sedimentation in rivers and shallowing of the Tapin Reservoir so that the service life of the reservoir is reduced. The importance of good land conversion management and the existence of national strategic infrastructure in the form of dams that need to be maintained for sustainability. A study was conducted to determine the value of the critical level of land and the amount of erosion in the Tapin Dam watershed. Based on the USLE formula using GIS analysis, four USLE method parameters are required, namely rainfall erosivity, soil erodibility map, land use map, and slope map. The overlay process is carried out to obtain the value of the amount of erosion to calculate the sediment transport ratio that occurs. The results of this study are the value of the erosion rate in the Tapin Dam watershed of 15,424.28 tons/ha/year and the amount of sedimentation released is 8,892,228.83 tons/year or 637.35 tons/ha/year

Structural Response of a Reinforced Concrete Building to Earthquake Excitation: A Nonlinear Time-History Analysis Case Study in Palu, Indonesia

Indah Nur Afiah — 2025-12-08

Palu is one of the regions with high seismicity due to its location directly on the Palu-Koro Fault, the longest active fault in Indonesia. A post-earthquake structural response evaluation was conducted on a reinforced concrete office building in Palu, Indonesia, using nonlinear time-history analysis to assess its performance under seven recorded ground motions. This evaluation serves as a reference for determining the structural functionality, safety against collapse, and the need for structural reinforcement due to earthquake loads. The primary focus was to assess the serviceability limit state and ultimate limit state in accordance with SNI 1726:2019 and to determine the performance level category based on ATC-40. Modeling was conducted using ETABS software with input from earthquake accelerograms of the Superstition Hills, San Fernando, Kobe, Loma Prieta, El Centro, Caldiran, and Manjil earthquakes. The results show significant variations among the earthquake scenarios. The highest displacement and drift values occurred in the Y-direction due to the El Centro earthquake, while the lowest values were observed in the X-direction during the Caldiran earthquake. Only the Caldiran earthquake met the limit criteria in both directions. Based on ATC-40, three earthquakes (Caldiran, Loma Prieta, and San Fernando) reached the Immediate Occupancy (IO) and Life Safety (LS) levels. In comparison, the other four earthquakes showed levels exceeding Collapse Prevention (>CP), indicating potential building failure and high hazard risks. Therefore, further evaluation and retrofit recommendations are necessary to enhance the structure's capacity and stiffness, thereby achieving the desired performance level in all earthquake scenarios.

Ceramic Waste as a Viable Alternative to Natural Aggregates in Concrete: Workability and Strength Analysis

Saniul H. Mahi — 2025-12-08

Concrete is one of the most frequently employed building materials because to its superior mechanical performance and long-term durability; yet, its pervasive usage adds to resource depletion and considerable environmental impacts, mainly from cement manufacturing and aggregate extraction. To address these problems, this study studies the inclusion of ceramic waste as a sustainable alternative to natural aggregates in concrete. The purpose was to examine the impact of ceramic waste on workability, compressive strength, and split tensile strength. A total of sixteen concrete mixes were made, comprising one control mix and fifteen mixes with different quantities of ceramic waste as fine and coarse aggregate replacements. The mix design followed a ratio of 1:1.67:2.81 with a water-to-cement ratio of 0.50, targeting a 28-day compressive strength of 20 MPa. Workability was examined using the slump test, while compressive and split tensile strengths were recorded at 7 and 28 days in line with ASTM standards. The experimental data show that partial replacement of fine aggregates at 10–20% and coarse aggregates at around 10% gave optimal mechanical performance, with strength values similar to or above those of the control mix. Higher substitution levels resulted in losses in both workability and strength due to increased porosity and poorer bonding within the interfacial transition zone. Beyond technical performance, the study indicates that mixing ceramic waste into concrete minimizes landfill disposal and conserves natural resources, consistent with circular economy concepts. These results emphasize the potential of ceramic waste as a viable and eco-efficient material for sustainable concrete manufacturing

Visualization Analysis of Concrete Incorporating Waste Tire Rubber: A Knowledge Graph Approach

Sameh Fuqaha — 2025-12-08

The increasing disposal of waste tires presents a global environmental challenge, necessitating innovative recycling solutions. Incorporating waste tire rubber into concrete offers a sustainable approach to mitigating landfill accumulation while promoting eco-friendly construction materials. However, research on rubberized concrete remains fragmented, necessitating a systematic visualization of its evolution, key contributors, and emerging innovations. This study employs a knowledge graph approach to analyze bibliometric data on concrete incorporating waste tire rubber, identifying major trends, research clusters, and influential studies. Using VOSviewer and bibliometric techniques, the study maps the intellectual landscape, revealing a significant rise in publications between 2019 and 2024, with China, India, and Australia leading contributions. Keyword analysis highlights key challenges such as reduced compressive strength, durability concerns, and workability issues, while also identifying solutions like surface treatments and supplementary cementitious materials. Citation analysis indicates that research primarily focuses on mechanical performance and sustainability, underscoring the need for further exploration of long-term durability and large-scale applications. The findings offer valuable insights for researchers and industry professionals, supporting the optimization of rubberized concrete formulations and its broader adoption in sustainable construction.

Factors Affecting the Success of Lean Construction Implementation in Indonesia

Moch Rian Silmi — 2025-12-08

The construction industry in Indonesia contributes significantly to the economy, but lags behind in technology adoption and faces environmental challenges. Lean Construction offers a solution by improving efficiency through waste reduction and value addition, although its application is still limited due to work culture resistance and low priority. This study aims to identify the factors that affect the success of lean implementation in East Java using SEM-PLS surveys and analysis. The results showed that organizational policies had a significant influence (46.2%), followed by teamwork (29.6%) and leadership (23.9%). Leadership is influenced by manpower and resources (71.1%), while organizational policies are influenced by optimization (88.7%). However, some variables, such as manpower vs. teamwork and optimization vs. leadership, don't have a significant influence. This study provides strategic insights to support the effective implementation of Lean Construction to improve the performance of the construction industry in Indonesia.

Mechanical Behavior Of Cement Treated Sand With Ordinary Portland Cement (OPC)

Syirly Adella Wijayanti Hariono — 2025-12-08

Cement Treated Sand (CTS) plays a pivotal role in enhancing poorly graded sandy soils, which inherently lack cohesion and pose challenges for infrastructure development. This study investigates the influence of varying cement percentages (6%, 8%, 10%, and 12% by dry weight of sand) on the mechanical properties of CTS. Tests were conducted for Unconfined Compression Strength (UCS) and California Bearing Ratio (CBR) to evaluate compressive strength and soil bearing capacity, respectively. The findings demonstrate that increasing cement content improves compressive strength but may diminish ductility. Therefore, optimizing cement ratios is essential to strike a balance between strength enhancement and material durability. This research underscores the critical role of CTS in stabilizing poorly graded sandy soils, offering valuable insights for enhancing infrastructure resilience in coastal areas prone to these soil types.

Factors Affecting Cost Performance Completion On Toll Road Projects With Turnkey Contracts

Muhammad F. A. Bakhri — 2025-12-08

Currently, the implementation of turnkey contracts has recently gained significant attention due to several advantages, such as shorter construction durations, improved construction quality, and reduced overall project costs. However, compared to the traditional Design-Bid-Build (DBB) method, the higher degree of uncertainty in turnkey projects introduces substantial risks, particularly for contractors. Project success in the construction industry is commonly evaluated based on cost performance relative to the planned budget. This study aims to identify and analyze the key variables influencing cost performance in toll road projects delivered through turnkey contracts. A quantitative research approach was applied using Structural Equation Modeling (SEM) with Partial Least Squares (PLS).The study involved 60 respondents representing service providers, ranging from general managers to administrative staff, who were directly engaged in toll road projects using turnkey contracts. Data were collected through structured questionnaires and interviews. The results indicate that contract conditions have the most significant positive impact on cost performance, with a path coefficient of 0.421, influenced by the field conditions variable. Variations in contract conditions or Contract Change Orders (CCOs) were found to significantly affect cost performance. Therefore, identifying potential risks to field conditions and conducting detailed field investigations are critical to maintaining cost control and ensuring project success.