RESPON PENDOPO JOGLO YOGYAKARTA TERHADAP GETARAN GEMPA BUMI

Abstract

After May 2006 earthquake the two Pendopo Joglo buildings in Yogyakarta, as displayed in figure 1A and 1B, were showed different failures. In Pendopo Joglo 1A, the sokoguru was broken right under the sunduk kili causing the building to collapse. On the other hand, in Pendopo Joglo 1B case, the sakaguru was slipped but still remained on its position on the umpak so the building did not collapse. The structure differences between the two buildings were the support system used for each building. Pendopo Joglo 1A used pen and hole in the sokoguru base to act as pin joint support, while in Pendopo Joglo 1B, the sokoguru was only placed on the umpak, so it could slip if the earthquake shook it. The slip (as in 1B case) restrained the earthquake vibration as could be learned in base isolator technology. This writing is not a study based on field observation but an analysis about the two buildings different responses to the earthquake vibration which was caused by the different support character. This analysis is based on Static Equivalent Earthquake Load Analysis and is using qualitative method. Abstract in Bahasa Indonesia: Dua buah bangunan Pendopo Joglo di Yogyakarta pada gambar 1A dan 1B mengalami kerusakan berbeda setelah kejadian gempa bumi bulan Mei 2006. Pada Pendopo Joglo 1A sokoguru patah tepat dibawah sunduk-kili dan bangunan runtuh, sedangkan pada pendopo joglo 1Bsokoguru bergeser posisinya pada tumpuan umpak, tapi bangunan tidak runtuh. Perbedaan struktur kedua bangunan terletak pada sistem tumpuannya, yaitu Pendopo Joglo 1A menggunakan tumpuan sendi berupa pen dan lubang di kaki sokogurunya, sedangkan pada pendopo joglo1B sokoguru hanya diletakkan diatas umpak sehingga dapat bergeser apabila digetarkan gempa. Pergeseran ini memberikan sifat meredam getaran gempa yang dapat dipelajari dari teknologi base-isolator. Tulisan ini bukan sebuah penelitian yang didasarkan pada fakta lapangan, tapi berisi analisis tentang perbedaan respon kedua bangunan terhadap getaran gempa akibat adanya perbedaan sifat tumpuan. Analisis dalam tulisan ini didasarkan pada analisis beban gempa statik ekivalen (2) dan dibahas secara kualitatif Kata kunci: gempa, Pendopo Joglo, sistem tumpuan, repon struktur, peredaman.