The design of a local road connecting Danau Jurug to Pantai Tebing Cluak’an was
undertaken to address the critical need for transportation infrastructure that supports
regional accessibility, economic development, and traffic safety. This study integrates
geometric design, pavement design, and geotechnical engineering into a cohesive
planning framework. The primary objective of this project is to develop a technically
sound and economically feasible roadway by analyzing multiple alignment alternatives,
assessing subgrade conditions, predicting settlement, and ensuring long-term structural
performance.
The research began with the selection of the optimal road alignment using the
Analytic Hierarchy Process (AHP) in Autodesk Civil 3D. Four alternatives were
compared based on criteria including geometric suitability, earthwork efficiency, slope
stability, and cost-effectiveness. Alignment 4 was selected as the final alignment due to
its favorable balance of horizontal and vertical geometry, minimal earthwork volume, and
adaptability to natural terrain contours. The horizontal alignment incorporated
appropriate curve radii and superelevation to accommodate vehicle dynamics and safety.
Vertical alignment was designed using parabolic curves, ensuring smooth transitions and
sufficient sight distances in both crest and sag curves.
In the pavement design phase, the projected traffic volume and Equivalent
Standard Axle Loads (ESALs) were calculated using traffic growth data and Vehicle
Damage Factor (VDF) in accordance with Bina Marga standards. The selected pavement
structure consists of a surface course, base course, and subbase layer, designed to
distribute loads effectively and resist deformation. The California Bearing Ratio (CBR)
values obtained from field tests were used to determine pavement thickness. The
mechanistic-empirical method was employed to ensure the design meets both
performance and durability targets over the pavement’s intended lifespan.
Geotechnical investigation was conducted to assess the subgrade bearing capacity,
settlement potential, and slope stability. Field tests including Cone Penetration Test
(CPT) and Standard Penetration Test (SPT) were performed along the selected alignment.
Analytical and empirical methods—namely Terzaghi and Hansen approaches—were
used to evaluate soil bearing capacity. The results indicated that most segments of the
alignment have sufficient capacity, while weaker zones were reinforced through
replacement or improvement of subgrade materials. Additionally, embankment loading
was analyzed to estimate immediate and consolidation settlements. Results showed that
settlements remained within acceptable limits, ensuring the long-term performance of the
pavement structure.
Slope stability analysis was carried out using the Ordinary Method and the
Simplified Bishop Method in GeoStudio software. The calculated safety factor values
exceeded the minimum requirement of 1.5, indicating stable slope conditions for both cut
and fill sections. In particular, the slope along embankment zones was carefully designed
with appropriate compaction and geometry to mitigate the risk of sliding or erosion.
Where necessary, slope reinforcements were recommended to maintain safety in areas
with weak soil or high-water content.
The comprehensive nature of the design addresses the core research problems
defined in the project: determining optimal alignment in complex terrain, improving traffic load prediction, evaluating subgrade response, ensuring slope stability, and
managing settlement. These components were analyzed within a clearly defined scope,
focusing on preliminary design stages and excluding construction details or special soil
conditions.
In conclusion, the “Local Road Project Design Danau Jurug – Pantai Tebing
Cluak’an” demonstrates an integrated civil engineering approach that combines design
optimization with field-based geotechnical evaluation. The methodology employed in this
project not only ensures structural integrity and road safety but also provides a scalable
template for similar local road development projects in varied terrain. The outcome of
this project is a resilient and sustainable road design that aligns with both national
standards and local context.