Three-Sided Arch Behavior Analysis As An Alternative To Box Culvert In Highway Construction

Culvert / box culvert (BC) is a square-shaped structure used as a drainage channel. In Indonesia, the use of BC has been widely applied to drainage / widening road projects, while overseas (such as in the United States) has used more Three-Sided Arc (TSA). In 2018, the Imam Bonjol Road Widening Project in Denpasar used a 5.7 m BC span with 400 mm upper and lower plate thickness. Meanwhile, in TSA produced by Foley Products Company, with spans reaching 11 m, a 300 mm thickness plate is used, and no bottom plate is used.

Based on this, there is the potential for material savings by reducing the thickness of the top plate and removing the bottom plate from the BC structure, making it a different structure, namely the TSA structure. To find out how effective the TSA structure is as an alternative to the BC structure, further research needs to be done with the aim of reducing the cost of the next road widening construction.

The initial phase of the study begins with validating the model of laboratory test results and proceed with modeling the application model. There are 1 BC and 5 TSA models that will be modeled in this study. The BC model is a control model with BC-appropriate dimensions on the Imam Bonjol Road Widening project, TSA with a span of 4 m (TSA40), 5.7 m (TSA57), 7.7 m (TSA77), 9.7 m (TSA97) and 11.7 m (TSA117). BC and TSA structures are modeled using frames, shell and solid elements in SAP2000 software.

In this study, structural analysis is carried out by linear analysis to obtain the outcomes in the form of structural behavior (deformation, internal forces, stress) and reinforcement requirements in the structure. From this research, the optimum span and thickness of the TSA concrete slab will be obtained. The optimum dimensions obtained can be used for road widening designs in Indonesia. By using the optimum dimensions, it is expected to reduce the cost of road widening construction.

Keywords: box culvert, frame element, shell element, solid element, three-sided arc