No abstract

This paper describes tsunami disaster mitigation in the West Sumatra region with participatory technology assessment (pTA), which promotes direct interaction among member and experts to discuss issues and reach consensus for mitigation through provision of information and knowledge of science and technology. Two areas were examined: Padang, the capital city; and Painan city, a town in southern West Sumatra Province, Indonesia. Tsunami have damaged these areas at least three times: in 1797, a 5-10-m-high tsunami wave height hit the area; in 1833, a 3-4-m-high tsunami came; and in 2007, an 8.4 Mw earthquake generated a local tsunami with maximum wave height of 1.5 m, as observed near Painan. Because of the high level of tsunami risk resulting from its flat topographic conditions, their respective populations of 820,000 people and 15,000 people are developing tsunami mitigation efforts with support of national institutions and international experts. These cities had different starting points and approaches. Efforts were introduced to produce official tsunami hazards maps. Insights from these lessons and ideas arising from the ongoing process after the 2007 South Sumatra and 2009 Padang earthquakes are discussed herein. Keywords: Tsunami disaster mitigation; pTA; tsunami model. 341 J. Earthquake and Tsunami 2010.04:341-368. Downloaded from www.worldscientific.com by UNIVERSITY OF CALIFORNIA @ SAN DIEGO on 02/03/15. For personal use only. J. Earthquake and Tsunami 2010.04:341-368. Downloaded from www.worldscientific.com by UNIVERSITY OF CALIFORNIA @ SAN DIEGO on 02/03/15. For personal use only.

ABSTRACT:The physical properties of sand soil which give effect to the resistance of liquefaction include grain size and density. Those physical properties of sand soil associated to liquefaction resistance have been studied in laboratory. Based on that study, the method to assess the liquefaction potential then is proposed. In laboratory tests, the vibration source is given by using the shaking table. During the tests, the acceleration and settlement are recorded. It then concluded that there is a relationship between density and gain size particles associated with liquefaction resistance for certain acceleration of vibration. The cone penetration and relative density relationship has been developed based on experiments in laboratory. Based on the results of those laboratory tests, the liquefaction potential of a certain site then assessed. It is found that the relative density and mean gain size relationship can be used to assess liquefaction potential in sand deposits.

Millions of non-engineered constructions in Indonesia are vulnerable to earthquake. Therefore, a simple, affordable and replicable method to strengthen the existing non-engineered construction in Indonesia is introduced. The retrofitting method described in this report is based on the principle of sandwich structures, having a masonry wall as core and covered on both sides with ferrocement layers. Numerical analysis result and shaking table test is included in this paper.

Gempa bumi yang melanda Sumatera Barat, 6 Maret 2007 merupakan salah satu bentuk pengulangan gempa di masa lalu dan merupakan petunjuk yang jelas bahwa belum banyak yang dilakukan berkaitan dengan rumah sederhana. Berdasarkan temuan di hampir semua gempa yang menimpa daerah Sumatera Barat, bangunan yang mengalami kerusakan dan roboh adalah rumah sederhana yang dibangun secara spontan (non engineered house), dimana bangunan dibangun berdasarkan pengalaman praktis tanpa perhitungan struktur. Salah satu bentuk kerusakan pada komponen non-struktur dan struktur adalah hubungan antara kolom dan dinding bata, dimana terjadi retak dan pemisahan antara kolom dan dinding akibat tidak ada angkur (stek). Kebanyakan bangunan yang ada dibuat pada masa yang tidak mengingatkan orang akan bahaya gempa bumi. Untuk gempa yang tidak terlalu besar, bangunan kemungkinan akan tetap berdiri dengan sedikit kerusakan. Namun untuk mengantisipasi gempa bumi yang kuat dan mengurangi dampak buruk yang ditimbulkan, maka bangunan rumah berdinding tembok tersebut harus dibangun sesuai ketentuan konstruksi bangunan tahan gempa dengan memberikan perkuatan pada bagian-bagian tertentu seperti pemasangan angkur (stek) dari kolom ke dinding sebagai salah satu perkuatan hubungan. Untuk mengetahui berapa besar pengaruh dari pasangan angkur (stek) dari kolom ke dinding bata, dilakukan penelitian terhadap dinding yang lengkap dengan sloof, kolom dan ringbalok. Pengujian dilakukan terhadap 2 benda uji yaitu benda uji yang menggunakan angkur (stek) dan tidak menggunakan angkur (stek), sehingga diharapkan dapat diketahui perilaku pemasangan angkur. Keywords : Gempa, angkur, rumah sederhana.