Di Malaysia, langkah mitigasi utama untuk menghalang tsunami telah diambil berat dan strategi pemindahan telah dirancang selepas peristiwa 2004 Indian Ocean Tsunami. Walau bagaimanapun, taktik yang sama ini tidak dapat diaplikasikan terhadap infrastruktur pantai terutama superstruktur jambatan darat yang berdekatan pantai. Sehingga kini, reka bentuk struktur jambatan rintang tsunami masih belum dirumuskan di Malaysia. Hal ini disebabkan kekurangan pengetahuan mengenai impak tsunami terhadap jambatan. Oleh itu, anggaran daya tsunami terhadap superstruktur jambatan adalah diperlukan di Malaysia. Dalam kajian ini, daya-daya tsunami terhadap tiga jenis superstruktur jambatan telah dikaji. Tiga jenis superstruktur jambatan ialah geladak jambatan dipermudahkan, geladak jambatan rasuk I dan geladak jambatan galang kotak. Semua model jambatan telah diskala-turunkan dengan 1:100. Eksperimen ini dijalankan di dalam flum ombak yang berdimensi 1 m × 1 m × 40 m. Model geladak jambatan diletakkan 30 mm, 40 mm dan 50 mm dari dasar flum ombak. Model tersebut dikenakan ombak ketinggian nominal 40 mm, 60 mm dan 80 mm. Keputusan eksperimen menunjukkan kekuatan serangan ombak terhadap model jambatan bergantung kepada ketinggian geladak jambatan dan ketinggian nominal gelombang tsunami. Apabila ketinggian nominal tsunami meningkat dan ketinggian geladak jambatan direndahkan, tekanan dan daya tsunami yang dikenakan adalah lebih tinggi. Dari keputusan eksperimen, persamaan taburan tekanan yang berada di lokasi yang berbeza untuk setiap model geladak jambatan telah dicadangkan. Kestabilan setiap jenis geladak jambatan terhadap gelongsor juga telah dinilaikan.
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In Malaysia, the primary mitigation measures of tsunami have been concerned and evacuation strategies had been planned after the event of 2004 Indian Ocean Tsunami. However, it does not address the same mitigation tactic to the coastal infrastructure especially the onshore bridge superstructures nearby the coastline. To date, proper design of tsunami-resistant bridge superstructure is yet to be formulated in Malaysia due to lack of knowledge on tsunami impact on bridge superstructure. Therefore, there is a need to estimate tsunami loading on bridge superstructure in Malaysia. In this research, the tsunami forces on three different types of bridge superstructures were investigated. They were simplified deck model, I-beam deck model and box girder model. All bridge models were downscaled with 1:100. The experiment was carried out in a wave flume of 1 m × 1 m × 40 m. The bridge deck models were placed 30 mm, 40 mm and 50 mm from the bed of flume. The bridge models were subjected to 40 mm, 60 mm and 80 mm of nominal wave height in all cases. The experimental results reveal that the nature of the wave attack on bridge models depends largely on the deck clearance and the nominal height of incident wave. In general, the wave pressures and forces increase when the nominal wave height increases and the deck clearance decreases. From the results, the equation for pressure distribution at different faces of each type of bridge model was proposed. The stability of each type of bridge model against sliding was evaluated.
Estimation of tsunami forces on three different types of bridge superstructure / Koon Foo Siong