Karakteristik Dinamik Bola Baja Sebagai Material Isolasi Seismik

Benyamin Bontong, Harun Mallisa, Tan Suryani Sollu

Abstract


Abstrak. Sistem isolasi seismik yang tersedia dewasa ini menggunakan teknologi canggih dan umumnya digunakan pada bangunan berlantai banyak. Penelitian ini mengkaji karakteristik isolasi bola baja yang sederhana tetapi diharapkan handal untuk bangunan rumah. Beban bangunan dimodelkan sebagai massa tunggal dan meja getar memodelkan tumpuan dasar (base). Isolasi bola dipasang di antara massa dengan meja getar. Rumah bola dibuat dua macam yaitu berbentuk tabung belah dan ½ bola. Beban siklis diaplikasikan pada meja getar dengan amplitudo 5, 10 dan 20 mm, frekuensi 151 dan 240 cpm. Friksi dalam sistem isolasi diukur. Respons massa dalam gerakan satu arah direkam pada kertas skala. Hasil penelitian menunjukkan bahwa semakin tinggi percepatan meja getar am, semakin besar persentase redaman percepatan yang dirambatkan ke massa. Dalam rentang parameter input yang diaplikasikan, untuk rumah bola berbentuk tabung belah, redaman percepatan mencapai 92% sampai dengan 99 %, sedangkan untuk rumah bola berbentuk ½ bola mencapai 35% sampai dengan 92 %. Rumah bola berbentuk tabung belah jauh lebih efektif meredam percepatan dibandingkan dengan rumah bola berbentuk ½ bola, dengan angka perbandingan respons percepatan massa 1:7 sampai 1:8.

Abstract. Seismic isolation systems being available recently are sophisticated technology and commonly used to reduce multi-storey building response from seismic ground motions. The simple steel ball isolation was conducted to predict the reliability of housing structures in response of seismic ground motion due to earthquake. To develop a model, the building loads are assumed as a single mass system and a vibration table as a supporting base. The steel ball isolation was installed between the mass and the table. Two houses shapes are made, that is, a split cylinder and an half ball. Sinusoidal forces were applied on vibrating table with the amplitudes of 5, 10 and 20 and the frequencies of 151 and 240 cpm. Frictions in the isolation system were measured, while movements of mass responses based on one direction displacement were recorded on scaling papers. This research reveals that the higher the vibrating table acceleration (am), the higher the percentage of  damping spreads through the mass. In the range of the application of input parameters, the accelerations are reduced from 92% to 99 % for split cylinder ball’s house, and from 35% to 92 % for half-ball ball’s house. The split cylinder-ball house is much more effective to reduce acceleration than the half-ball house. Those ratios of mass acceleration responses are from one eighth to one seventh.

Keywords


Isolasi bola baja; Frekuensi; Amplitudo; Percepatan.

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References


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