Analisis Struktur Perbandingan Gedung Menggunakan Base Isolation Head Damping Rubber Bearing (HDRB) dan Friction Pendulum System (FPS)

Gempa bumi merupakan ancaman signifikan bagi bangunan bertingkat, sehingga evaluasi dan
peningkatan kinerja seismik perlu dilakukan terutama pada gedung yang dirancang dengan standar
lama. Penelitian ini bertujuan untuk menganalisis perbandingan kinerja struktur pada gedung
perkuliahan 7 lantai di Surabaya dengan Kategori Desain Seismik D (KDS-D) yang diasumsikan
berdiri di Aceh, wilayah dengan intensitas kegempaan tinggi. Evaluasi dilakukan terhadap dua jenis
base isolation, yaitu Head Damping Rubber Bearing (HDRB) dan Friction Pendulum System (FPS),
untuk menilai efektivitasnya sebagai metode retrofit. Analisis dilakukan menggunakan 11 ground
motion dengan metode Nonlinear Dynamic Analysis, mencakup parameter respons seperti base shear,
displacement, ductility demand, story drift, dan residual transient drift. Pada kondisi awal fixed-base,
struktur menunjukkan respons gempa yang tinggi dengan gaya geser dasar maksimum sebesar
34.047,14 �� pada arah-X dan 34.207,69 �� pada arah-Y. Kondisi ini mengindikasikan tingkat
kerusakan berat hingga mencapai level collapse prevention (CP) akibat peningkatan tuntutan seismik
di Aceh. Penerapan sistem isolasi HDRB dan FPS menunjukkan reduksi signifikan terhadap respons
lateral bangunan. HDRB mampu menurunkan gaya geser dasar sebesar 55,1% pada arah-X dan 57,4%
pada arah-Y, sementara FPS memberikan reduksi sebesar 54,4% pada arah-X dan 57,6% pada arah-Y.
Peningkatan kinerja ini menyebabkan tingkat kerusakan struktur beralih dari collapse prevention (CP)
menjadi life safety (LS) hingga immediate occupancy (IO). FPS tercatat memberikan kinerja lebih baik
dalam menurunkan gaya geser dasar dibandingkan HDRB. Secara keseluruhan, penggunaan base
isolation dinilai efektif meningkatkan performa seismik struktur, meskipun kombinasi dengan metode
retrofit tambahan masih diperlukan untuk mencapai hasil yang lebih optimal.

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Earthquakes pose a significant threat to multi-story buildings, so seismic performance evaluation and improvement are necessary, especially for buildings designed to older standards. This study aimed to analyse the comparative structural performance of a 7-story lecture building in Surabaya with a Seismic Design Category D (KDS-D), assumed to be located in Aceh, an area with high seismic intensity. The evaluation was conducted on two types of base isolation systems, the Head Damping Rubber Bearing (HDRB) and the Friction Pendulum System (FPS), to assess their effectiveness as retrofit methods. The analysis was conducted using 11 ground motions with the Nonlinear Dynamic Analysis method, including response parameters such as base shear, displacement, ductility demand, story drift, and residual transient drift. In the initialfixed-base condition, the structure showed a high earthquake response with a maximum based-shear force of 34,047.14 kN in the X-direction and
34,207.69 kN in the Y-direction. This condition indicated a severe level of damage reaching the collapse prevention (CP) level due to increased seismic demands in Aceh. The application of the
HDRB and FPS isolation systems showed a significant reduction in the lateral response of the building. HDRB was able to reduce the base shearforce by 55.1% in the X-direction and 57.4% in the Y-direction, while FPSprovided a reduction of54. 4% in the X-direction and 5 7. 6% in the Y-direction.
This performance improvement caused the level ofstructural damage to shiftfrom collapse prevention (CP) to life safety (LS) to immediate occupancy (IO). FPS was recorded to provide better performance in reducing the base shear force compared to HDRB. Overall, the base isolation was considered effective in improving the seismic performance ofstructures, although a combination with additional retrofit methods was still necessary to achieve more optimal results.