Nusantara Civil Engineering Journal

Forensic Investigation of the Steel Pile Pipe of the Mahakam Dolphin After Collision Using Side Scan Sonar and Bathymetry

2026-06-23T13:33:44+00:00

The Mahakam River in Samarinda, East Kalimantan, Indonesia, is a critical maritime transportation route with high vessel traffic, increasing the risk of collisions with bridge protection structures like dolphins. This study presents a forensic investigation into the position and shape of steel pile pipes of the Mahakam Dolphin after a collision incident, employing integrated bathymetric and side scan sonar surveys. Conducted in April 2026, the survey utilized Garmin ECHOMAP UHD2 62SV and GT52HW-TM transducers for bathymetry, alongside side scan sonar for high-resolution underwater imaging. Results revealed a compact debris field of collapsed steel pile pipes and pilecap, covering approximately 500 m² with an average thickness of 1.5 m. Bathymetric data indicated significant riverbed alterations, including scouring and sedimentation patterns. The debris distribution analysis confirmed minimal dispersion due to low current velocities, posing navigation risks and potential structural instability to adjacent bridge piers. The study underscores the efficacy of combined geophysical techniques in post-collision forensic assessments and recommends relocating the dolphin structure to a debris-free zone. These findings provide actionable insights for maritime infrastructure management and collision impact mitigation

The Comparative Analysis of Bond Strength on Lightweight Concrete Block Surfaces Using Special Adhesive and Conventional Mortar

2026-06-23T12:46:26+00:00

Indonesia, as an earthquake – prone country, requires wall materials that are strong, efficient, and resistant to cracking. Lightweight concrete blocks have become one of the modern construction alternatives due to their light weight, high dimensional precision, and good thermal and sound insulation properties. However, the bonding quality between blocks remains a determining factor for wall durability under loads and vibrations. This strudy aims to analyze the effect of mixture composition on bond strength and to compare the use of specialized adhesive with conventional mortar. Samples of lightweight concrete blocks were produced using Portland cement type I, local fine aggregates from Muara Samu, water, and foam agent with variations of 2%, 4%, and 6%. The foam agent was incorporated using 4 bar air pressure, and specimens were cured for 28 days according to SNI standards. The test result show that specialized adhesive provides higher bond strength compared to conventional mortar. Bond strength decreases with increasing foam agent content, with average values for specialized adhesive of 0.80 MPa (2%), 0.73 MPa (4%), and 0.69 MPa (6%), while conventional mortar yielded 0.55 MPa (2%), 0.43 MPa (4%), and 0.39 MPa (6%). The largest difference occurred at 6% foam agent, amounting to 42.96%. These findings confirm that the use of local fine aggregates produces lightweight blocks with good bonding quality, while supporting sustainable development through regional resource optimization.

Utilization of Red Brick Demolition Waste as a Substitute for Fine Aggregate in Paving Block Mortar

2026-06-23T12:44:59+00:00

Paving blocks are construction materials composed of cement, fine aggregate, and water. Continuous use of natural fine aggregates may increase environmental exploitation; therefore, environmentally friendly alternative materials are needed, one of which is red brick demolition waste.

This study aimed to determine the effect of red brick waste substitution as fine aggregate on the compressive strength of paving block mortar. The substitution variations used were 0%, 5%, 10%, 15%, and 20% of the fine aggregate weight. Cube specimens measuring 5 cm × 5 cm × 5 cm were prepared with three samples for each variation. Compressive strength tests were conducted at the ages of 7 and 14 days.

The results showed that the highest compressive strength was obtained in the normal mixture (0%) with values of 142.75 kg/cm² at 7 days and 183.54 kg/cm² at 14 days. The addition of red brick waste reduced the compressive strength at the 5% variation, but the strength gradually increased up to the 20% variation. The 20% variation produced compressive strengths of 126.44 kg/cm² at 7 days and 127.80 kg/cm² at 14 days. Based on these results, red brick waste has the potential to be used as a partial substitute for fine aggregate in paving block mortar.

Microstructural Analysis of Stand Tyre Barrier: A Review of Blast-Induced Boundary Conditions

2026-06-23T12:43:32+00:00

This study evaluates the structural integrity of a Stand Tyre Barrier developed by PT. AWEfendi Geostruk Indonesia in Balikpapan, East Kalimantan, under static and blast loads. The barrier, designed to store large tires (CAT 777, 27.00R49), was analyzed using Finite Element Method (FEM) to withstand a static load of 1100 kg and dynamic blast energy of 1765 J. Key components included a 16 mm main plate, floor plate, and steel frame (angle 50×50×5 mm, UNP 150×75×6.5 mm, hollow 75×75×3.2 mm). Blast pressure was estimated at 86.3 kPa (incident) and 350 kPa (reflected peak). Results indicated maximum von Mises stress of 1791 kg/cm² (74.7% of allowable 2400 kg/cm² per SNI 03-1729-2002) and deformation of 0.011 cm (0.11 mm), confirming elastic behavior. Validations against experimental data (external work: 1765.4 kJ) confirmed model accuracy. The barrier meets safety standards but recommends material upgrades for larger-scale operations. This analysis provides a benchmark for blast-resistant industrial structures in high-risk environments.

Analyzing the Smartphone-Based 3rd order 2D Positioning: A cost-effective Alternative for mapping and Geospatial Data Acquisition

2026-06-23T12:42:05+00:00

This study explores the potential of smartphone-based 3rd order 2D surveying as a cost-effective alternative for mapping and geospatial data acquisition. Traditional surveying methods rely on expensive equipment, but smartphones offer a promising solution, leveraging their widespread availability and accessibility. The study evaluates the accuracy and reliability of smartphone-based 2D surveying techniques, focusing on environmental factors that impact accuracy. The research uses a Vivo Y04 smartphone with SW Maps and Geo++ RINEX Logger apps to collect data at seven control points in Lokoja, Nigeria. Results show that environmental factors like buildings, trees, and telecommunication masts significantly impact accuracy, with deviations ranging from 0.337m to 8.036m.Control points in open fields with good satellite geometry achieved deviations of less than 100cm, while those near obstacles showed larger discrepancies. The SW Maps app demonstrated more reliable results compared to Geo++ RINEX. A hybrid approach combining satellite surveying with traditional methods can help achieve accurate results. The study highlights the potential of smartphone-based surveying for small-scale projects, developing countries, or applications with limited budgets. However, careful planning and selection of survey locations are crucial to minimize errors. The findings have implications for urban planning, environmental monitoring, and infrastructure development, and suggest that smartphone-based 3rd order 2D positioning can be a viable alternative for geospatial data acquisition. By understanding the limitations and capabilities of smartphone-based surveying, professionals can leverage this technology to achieve accurate and reliable geospatial data. Further research is needed to optimize location-based services in urban settings and to investigate the impact of different smartphone models and surveying techniques on accuracy

Study of Furrow Planting System in the Limestone Reclamation Area of PT. "X", East Java Province

2026-06-23T12:40:39+00:00

The mining industry contributes significantly to economic development, but it also causes environmental impacts in the form of land degradation, particularly in limestone mining areas, which typically have very thin topsoil layers. This condition complicates the revegetation process and slows down the ecological recovery of the land. This study examines the strip planting system in the limestone mine reclamation area owned by PT X, East Java Province. The objectives of this study are to describe the technical stages of implementing the furrow planting system, describe the actual conditions of the furrow planting system implementation, compare the furrow planting system with the conventional system, and implement the furrow planting system on new land. The methods used are a combination of qualitative and quantitative approaches. Primary data required included soil quality, surrounding vegetation, planting distance, and row spacing, while secondary data required included WIUP data, RR documents, geological maps, plant height, plant diameter, and number of leaves. The results of the study show that the furrow planting system produces optimal teak growth compared to the conventional system. In addition to providing better vegetation growth, the furrow planting system has also been proven to be more efficient in the use of topsoil, requiring only 640 m3/Ha compared to 3000 m3 in the conventional system. Implementing this system on a new 3.2-hectare site is projected to require 2,306 trees and 2,234 m³ of topsoil, with seedlings sourced from stem cuttings. These results indicate that the ridge planting system is an effective and efficient method for supporting sustainable mine land reclamation.

Eco – Wudu’: Sustainable Watering System by Using Wudu Water

2026-06-23T12:39:10+00:00

The Eco-Wudu Sustainable Watering System project was developed to address the issue of wasting clean wudu water at the Polytechnic surau. This study was conducted because the amount of water used for ablution daily is high, and most of it is discharged directly into the drain without being reused. The main problem to be solved is the lack of an efficient water management system to recycle ablution water for other purposes, such as plant irrigation. The approach used in this project involves the development of an automatic prototype system that functions to collect and reuse ablution water.

The system consists of an Arduino Uno, soil moisture sensor, automatic water pump, storage tank, uPVC gutter channel, and a solar panel as a green energy source. Data were collected through tests on water flow rate, soil moisture levels, and the amount of water saved before and after the project implementation. The findings show that the system operates effectively in automatically controlling irrigation when the soil reaches a certain level of dryness, thereby reducing the use of main water supply and improving energy efficiency. The analysis revealed a significant amount of water savings compared to the previous manual method.

In conclusion, this project not only contributes to green engineering practices and sustainable water management but also adds value to the surau community by fostering environmental awareness. For future studies, improvements can be made by integrating a more advanced water filtration system and connecting the system to an IoT-based database for real-time monitoring.

Keywords: Smart Irrigation System; Recycled Ablution Water; Arduino; Solar Energy; Absolute Error; Standard Deviation;