Civil Engineering Collaboration

The Effect of Lime Addition on Consistency and Maximum Stress in Silt-Clay Soil

2025-12-28T21:23:55+07:00

Silty–clayey soils with moderate to high plasticity often present geotechnical problems due to high compressibility, low bearing capacity, and sensitivity to moisture variations. This study aims to evaluate the effect of lime addition on soil consistency characteristics and maximum stress, and to investigate the quantitative relationship between the plasticity index (PI) and maximum stress (qu) as an integrated approach for assessing soil stabilization. Laboratory tests were conducted using lime contents of 0%, 3%, 5%, 7%, and 9% by dry weight of soil. The evaluated parameters included liquid limit (LL), plastic limit (PL), plasticity index (PI), and unconfined compressive strength (UCS). The results indicate that lime addition significantly reduced the plasticity index from 23.13% to 8.89%, accompanied by an increase in maximum stress from 0.119 kg/cm² to 0.291 kg/cm². Regression analysis revealed a strong negative linear relationship between PI and qu, with a coefficient of determination (R²) of 0.98. The optimum lime content was found to be in the range of 5–7%, providing the most efficient combination of plasticity reduction and strength improvement. These findings suggest that the plasticity index has strong potential to be used as a preliminary parameter for estimating strength improvement in lime-stabilized silty–clayey soils during the early stage of ground improvement planning.

Performance Evaluation of the RSUP Dr. M. Djamil Intersection, Jalan Perintis Kemerdekaan, Padang City

2026-07-20T13:56:43+07:00

Rapid growth in the number of vehicles in Padang City has caused traffic congestion at critical locations, one of which is the Dr. M. Djamil General Hospital (RSUP) intersection. Although equipped with traffic signal infrastructure, the intersection currently operates as an unsignalized junction because the traffic lights are not in use. This study aims to evaluate existing performance and propose alternative solutions based on the 2023 Indonesian Road Capacity Manual (PKJI). Primary data were obtained through field surveys conducted over four days during morning, midday, and evening peak periods. Analysis of existing conditions during the evening peak hour (Saturday, 17:00–18:00 WIB) revealed a degree of saturation (DS) of 0.89 and an intersection delay of 15.34 seconds/vehicle, corresponding to Level of Service C (stable flow, moderate density). Three alternative solutions were examined: installing traffic signals (3-phase), widening the major road combined with traffic signals, and widening the major road without traffic signals. Comparative results indicate that Alternative Solution 3 (widening the major road by 1 meter without traffic signals) is the most effective, yielding a DS of 0.87, a delay of 14.84 seconds/vehicle, and Level of Service B.

Analysis of Compaction Quality of Class A Aggregate Base Using the Sand Cone Method on the Teluk Tapang Port Access Road

2026-07-20T13:55:36+07:00

This study, entitled “Analysis of Compaction Quality of Class A Aggregate Base Using the Sand Cone Method on the Teluk Tapang Port Access Road Project”, aims to evaluate the field compaction quality and its conformity with the applicable technical specifications. The research scope includes field data collection of moisture content and in-situ density on the Class A aggregate base layer at several test points along the access road alignment to Teluk Tapang Port. The method used is the Sand Cone Test in accordance with SNI 03-2827-2011, to determine the in-situ dry density of the compacted layer. The field density values were compared to the laboratory maximum dry density obtained from the Modified Proctor Test, to calculate the degree of compaction (% compaction). The data were analyzed descriptively to observe the relationship between moisture content and compaction level, as well as to evaluate compliance with Bina Marga standards, which require a minimum of 95% compaction for the upper base layer. The results from 60 test points show that the moisture content ranged from 1.32% to 17.7%, with an average of 7.49%, while the compaction percentage ranged from 51.19% to 99.70%, with an average of 86.15%. Evaluation results indicate that 46.7% of the test points achieved compaction above 90%, and only 21.7% met the 95% requirement set by Bina Marga standards. It can be concluded that the compaction quality of the Class A aggregate base layer on this project has not fully met the specified compaction standards, particularly at several stations with moisture content either above or below the optimum level. Therefore, better moisture control and compaction procedures are required to achieve more uniform and compliant results.

Analysis of Train Load Distribution on Concrete Sleepers on the Padang–Lubuk Buaya Rail Line

2026-07-20T13:54:10+07:00

The increasing operational speed and axle load of railway transportation require railway track structures capable of distributing loads safely and efficiently. Concrete sleepers play a crucial role in transferring loads from the rails to the ballast while maintaining track stability. This study aims to analyze the distribution of dynamic loads acting on concrete sleepers due to train movement and to evaluate the structural response of the railway track using the Beam on Elastic Foundation (BoEF) approach. The research employed a quantitative analytical method using secondary data obtained from railway technical standards, locomotive specifications, and track geometric parameters in accordance with the Indonesian Ministry of Transportation Regulation No. 60 of 2012. Dynamic loading was determined using the Talbot dynamic factor, followed by calculations of rail deflection, maximum bending moment, shear force, and load distribution to the sleepers based on the Winkler elastic foundation model. The results indicate that train speed significantly influences the magnitude of dynamic loads transmitted through the rail structure. Under the analyzed operating conditions, the calculated dynamic wheel load reached 11.77 kN, while the distributed load acting on the concrete sleeper was approximately 6.44 tons. The analysis demonstrates that the concrete sleeper is capable of distributing loads effectively and maintaining structural stability within the design parameters. These findings provide valuable information for railway track planning, maintenance, and evaluation to improve the safety, durability, and performance of railway infrastructure.

Evaluation of the Implementation of the Construction Safety Management System (SMKK) at the Novotel Batam Hotel Construction Project

2026-07-20T13:47:47+07:00

This study aims to evaluate the implementation of the Construction Safety Management System (SMKK) and to analyze the factors hindering its implementation in the Novotel Hotel construction project in Batam. A quantitative research method was used, with data collected through questionnaires distributed to 55 respondents consisting of project managers, supervisors, and construction workers. Data analysis was conducted using validity and reliability tests with SPSS, as well as the Relative Importance Index (RII) method. The results indicate that all variables are valid and reliable, with Cronbach’s Alpha values greater than 0.60. The implementation of SMKK is categorized as good, with a success rate of 79.22%, which falls into the “fairly good” category (silver flag certification). However, several obstacles were identified, including insufficient safety training, limited work facilities, low worker awareness, and unsafe environmental conditions. This study concludes that improvements in training, supervision, and safety facilities are necessary to enhance SMKK implementation and reduce the risk of construction accidents.