Eksperimen Laboratorium Pengaruh Hidung Pilar Jembatan Terhadap Kedalaman Gerusan Lokal Setimbang

Ichsan Rauf; Abdul Gaus; Imran Imran; Salsabila Jaelan

doi:10.29103/tj.v13i2.872

Eksperimen Laboratorium Pengaruh Hidung Pilar Jembatan Terhadap Kedalaman Gerusan Lokal Setimbang

Ichsan Rauf, Abdul Gaus, Imran Imran, Salsabila Jaelan

Abstract

Abstrak

Gerusan lokal yang terjadi disekitar pilar jembatan sangat mempengaruhi stabilitas struktur atas jembatan yang dapat menyebabkan kegagalan struktur jembatan. Salah satu modifikasi hidrolika aliran untuk mereduksi besaran gerusan lokal pada pilar jembatan dapat dilakukan dengan merubah geometri pilar jembatan. Penelitian ini difokuskan pada pengaruh hidung (nose) pada struktur pilar terhadap kedalaman gerusan lokal (scouring) setimbang yang terjadi. Eksperimen laboratorium dilakukan dengan menggunakan perangkat saluran terbuka (set circulating flume) dengan dimensi panjang 740 cm, lebar 28 cm, dan tinggi 40 cm. Asumsi aliran yang digunakan adalah aliran tetap (steady flow) dengan debit sebesar 0,0252 m³/det, sementara geometri pilar yang digunakan dalam penelitian ini berupa pilar dengan radius 1 cm; 1,5 cm; dan 2 cm. Pengukuran kedalaman gerusan dilakukan di sekitar pilar dengan interval waktu 30 menit hingga kedalaman scouring setimbang tercapai. Hasil penelitian ini menunjukkan bahwa dengan semakin kecil nose pilar maka semakin kecil pula scouring yang terjadi, serta nose pilar juga mampu mereduksi waktu terjadinya scouring setimbang.

Kata kunci: Gerusan lokal, modifikasi hidung pilar, kedalaman gerusan setimbang

Abstract

Local scour that occurs around the bridge pillars affects significantly the stability of the bridge superstructure, where it will generate the bridge structure failure. Modifications the geometry of the bridge pillars is one of the effort inorder to reduce the depth of local scouring. This research conducted the effect of geometry pllars modification, particularly on nose pillar, against the the depth of local scouring at the equilibrium state. Laboratory experiments were carried out by using an open channel device/a set circulating flume, with dimensions of 740 cm in length, 28 cm in width and 40 cm in height. The flow assumption used is a steady flow with a discharge of 0.0252 m³/s, while the pillar geometry used in this study is a oblong pillar with a radius mayor at nose are 1 cm; 1.5cm; and 2 cm. Scouring depth measurements were carried out around the pillars at intervals of 30 minutes until an equilibrium scouring depth was reached. The results of this study indicate that the smaller of nose pillar, the smaller the scouring that occurs, and the nose pillar is also able to reduce the time of equilibrium local souring.

Keywords: Local scouring, nose pillar modification, depth scouring equilibrium

Keywords

Local scouring, nose pillar modification, depth scouring equilibrium

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References

Abdallah Mohamed, Y., Hemdan Nasr-Allah, T., Mohamed Abdel-Aal, G. & Shawky Awad, A., 2015. Investigating the eﬀect of curved shape of bridge abutment provided with collar on local scour ,experimentally and numerically. Ain Shams Engineering Journal , Volume 6, pp. 403-411.

Akan, O. A., 2006. Open Channel Hydraulics. 1st ed. Burlington: Elsevier.

Anwar, et al., 2021. Studi Eksperimental Pengaruh Radius Pilar Massif Terhadap Pola Gerusan Lokal. Simetrik.

Chang, H., 1988. Fluvial Process in River Engineering. s.l.:John Wiley & Sons, 1988..

Chiew, Y., 1995. Mechanics of Rriprap Failure at Bridge Piers. J. Hydraul. Eng., Volume 121, pp. 635-643.

Chiew, Y. M., 1984. Local scour at bridge piers, Report No. 355, , Auckland, New Zealand: School of Engineering, The University of Auckland.

Chiew, Y. M., 1992. Scour protection at bridge piers. J. Hydraulic Engineering, 118(9), pp. 1260-1269.

Chiew, Y. & Melville, B. W., 1987. Local Scouring on Bridge Piers. Journal Of Hydraulic Research, Volume 25, pp. 15-26.

Dargahi, B., 1990. Controlling Mechanism of Local Scouring. Journal of Hydroulic Enggineering, Volume 116, pp. 1197-1214.

Deng, L. & Cai, C. S., 2010. Bridge Scour: Prediction, Modeling, Monitoring, and Countermeasures—Review. Practice Periodical On Structural Design And Construction, 15(2), pp. 125-134.

Dey, S., 2014. Bedforms. In Fluvial Hydrodynamics. GeoPlanet: Earth and Planetary Sciences, p. Springer.

Ettema, R., Constantinescu, G. & B, M., 2011. Evaluation ofBridge Scour Research: Pier Scour Processes and Predictions, s.l.: National Cooperative Highway Research Program 175 (NCHRP 175).

Fael, C., Lança, R. & António, C., 2014. Pier Shape And Alignment Effects On Local Scour. Nantes, SHF Conference: "Small scale morphological evolution Of costal, estuarine and river systems".

Fael, C., Lança, R. & Cardoso, A., 2016. Effect of pier shape and pier alignment on the equilibrium scour depth at single piers. Int. J. Sediment Res, pp. 1-7.

Garde, R. J. & Kothyari, U. C., 1998. Scour Around Bridge Piers. Pinsa, pp. 569-580.

Kattell, J. & Eriksson, M., 1998. Bridge scour evaluation: Screening, Analysis, & Countermeasures. s.l.:s.n.

Kumar, V., Raju, K. G. R. & Vittal, N., 1999. Reduction of local scour around bridge piers using slots and collars. Journal of Hydraulic Engineering, Volume 125, pp. 1302-1305.

Laursen, E. M. & Toch, A., 1956. Scour Around Bridge Piers And Abutments.

Melville, B. & Sutherland, A., 1988. Design method for local scour at bridge piers. J. Hydraul. Eng, Volume 114, p. 1210–1226..

Melville, B. W. & Coleman, S. E., 2000. Bridge Scour. New Zealand: Water Resources Publication, LLC.

Mia, M. & Nago, H., 2003. Design Method of Time-Dependent Local Scour at Circular Bridge Pier. Journal of Hydraulic Engineering, Volume 129, pp. 420-427.

Mohammed, T. A. et al., 2007. Physical Modeling of Local Scouring around Bridge Piers in Erodable Bed. Journal King Saud University, pp. 195-207.

Schlömer, O. & Herget, J., 2023. Geometry of Local Scour Holes at Boulder-like Obstacles during Unsteady Flow Conditions and Varying Submergence. Water, 15(5), p. 958.

Shamaa, M. T., 2020. Local Scour for Side Slopes Piers with Upstream Lenticular Nose. International Journal of Scientific & Engineering Research, 11(2), pp. 74-83.

Sumer, B. & Fredsøe, J., 2002. The Mechanics of Scour in The Marine Environment. Singapore: World Scientific.

Vijayasree, B., Eldho, T., Mazumder, B. & Ahmad, N., 2017. Influence of bridge pier shape on flow field and scour geometry. Intl. Journal River Basin ManagemenT, pp. 1-20.

DOI: https://doi.org/10.29103/tj.v13i2.872