GAYA ANGKAT PADA BLOK BETON LEPAS YANG DIAKIBATKAN OLEH GELOMBANG TSUNAMI

Tsunami are very dangerous and had a great destructive powers, not only because it has great wave energy, but also the debris that lifted and dragged along tsunami surge, add up the tsunami force. Debris such as a fraction of concrete column may be resulted from structures that were destroyed by tsunami surge. Concrete blocks block is commonly used as road pavement, for example in Parangtritis beach. Such concrete block is also vulnerable as they be lifted up and drag away as debris by tsunami. Indeed, a small block such a concrete pavement has little effect on large buildings. However, the impact of such debris on people during the event of tsunami can be devastating. Therefore, a study needed to be conducted to learn this phenomenon. The research was conducted using physical modeling. The simulations were carried out in a wave flume of 16.80 m length, 0.60 m wide, and 0.45 high, that was facilitated with tsunami generator based on dam break system. The models was made form concrete block. The dimensions were 3 cm long and 3 cm wide, whilst the thickness was varied. There were 2 cm, 1.75 cm, 1.5 cm, 1.25 cm, and 1 cm. the tsunami surge height and velocity were measured using a series of wave probes that were located along the flume downstream. a practical calculation was conducted to evaluate the condition of concrete block pavement in Parangtritis beach. The results of this study showed that the condition of moving and lifting concrete blocks are determined by the thickness of the concrete block and the velocity of the tsunami surge that was related with the heights of the surge. The lift force coefficient (CL) in this study is found approximately 0.08. The value of the lift coefficient can be used to estimate the condition of the concrete block as a result of the tsunami surge flow. For concrete block with density about 2200 kg/m3, will be moved when the ratio of the tsunami surge height and the thickness of concrete block (h / D) greater than or equal to 6, with the velocity of tsunami surge is greater than the velocity at the critical condition