ANALYSIS OF SLAB DEFLECTION IN THE MODIFIED CAKAR AYAM PAVEMENT SYSTEM USING DISPLACEMENT FACTOR DERIVED FROM PURI'S GRAPH

Abstract

The pre-designed Modified Chicken Claw (MCA) pavement system can use the Hardiyatmo Method graph for pavements with a width of 7.5 m, where under the pavement slab, there are three claws with a diameter of 0.8 m and a height of 1.2 m, as well as a distance between the claws of 2.5 m. An equivalent modulus of subgrade reaction (k’) was proposed to analyze the Nailed-slab pavement system. The displacement factor was used to determine the additional modulus of subgrade reaction due to pile installing (Dk). This paper aims to apply the curve of displacement factor from Puri’s graph to calculate the deflection of the Modified Cakar Ayam (MCA) pavement system. Calculated deflections based on this curve were compared to the observed deflection. The deflection was calculated by using the Beam on Elastic Foundation method. Full-scale test result from the MCA pavement system was used. The concentric and edge loading points were considered. All calculated deflections were very over-estimated, around 260% to 665%, and higher than the allowable deflection of 5 mm in case of ignoring the end bearing resistance of a shell, except for concentric loads 40 kN (single wheel load). Calculated deflections by considering end bearing (Q_b > 0) were lower by more than 130% compared to calculated deflections by ignoring end bearing (Q_b = 0). In the case of MCA, the end bearing of the shell should be considered in the calculation. The displacement factor should be specially developed for MCA analysis.