Evaluasi Ketahanan Seismik Bangunan Vihara Vimalakirti di Jalan Madong Lubis Medan Sumatera Utara dengan metode Pushover

Abstract

Kota Medan merupakan salah satu kota metropolitan terbesar di Indonesia yang terus berkembang secara ekonomi dan infrastruktur. Banyak bangunan eksisting belum dirancang sesuai standar ketahanan gempa terbaru, salah satunya adalah Vihara Vimalakirti di Kota Medan. Penelitian ini bertujuan untuk mengevaluasi ketahanan seismik struktur bangunan Vihara Vimalakirti menggunakan metode Pushover, yaitu analisis statik nonlinier yang dapat menggambarkan kapasitas struktur dalam menahan beban gempa. Pemodelan dan analisis dilakukan menggunakan perangkat lunak SAP2000, berdasarkan data geometri, properti material, serta parameter pembebanan yang mengacu pada SNI 1726:2019. Evaluasi kinerja struktur dilakukan dengan menginterpretasikan kurva kapasitas (Pushover curve), story drift, dan pembentukan sendi plastis. Hasil analisis menunjukkan bahwa struktur mengalami perpindahan lateral maksimum sebesar 23,50 mm dan story drift ratio berada dalam batas yang diperbolehkan. Mayoritas sendi plastis terbentuk pada balok, mengindikasikan mekanisme Strong column–weak beam telah tercapai. Berdasarkan kriteria performa dari ATC-40 dan FEMA 356, struktur Vihara Vimalakirti berada pada tingkat kinerja Immediate Occupancy (IO), yang berarti bangunan masih aman digunakan pasca gempa dengan kerusakan minimal. Kurva kapasitas menunjukkan bahwa struktur mampu menahan beban lateral hingga batas elastisnya, meskipun terjadi konsentrasi deformasi pada lantai dasar. Potensi Soft Story dan sendi plastis yang terbentuk pada beberapa kolom lantai dasar menjadi indikasi perlunya perkuatan lokal agar bangunan tetap aman terhadap gempa yang lebih besar di masa mendatang. Medan is one of the largest metropolitan cities in Indonesia that continues to develop economically and infrastructurally. Many existing buildings have not been designed according to the latest earthquake resistance standards, one of which is the Vimalakirti Temple in Medan. This study aims to evaluate the seismic resistance of the Vimalakirti Temple building structure using the Pushover method, a nonlinear static analysis that can describe the capacity of the structure to withstand earthquake loads. Modeling and analysis were carried out using SAP2000 software, based on geometric data, material properties, and loading parameters referring to SNI 1726:2019. Structural performance evaluation was carried out by interpreting the capacity curve (Pushover curve), story drift, and plastic hinge formation. The analysis results showed that the structure experienced a maximum lateral displacement of 23.50 mm and the story drift ratio was within the permissible limits. The majority of plastic hinges formed in the beam, indicating that the Strong column–weak beam mechanism had been achieved. Based on the performance criteria of ATC-40 and FEMA 356, the Vimalakirti Temple structure is at the Immediate Occupancy (IO) performance level, meaning the building is still safe to use after the earthquake with minimal damage. The capacity curve shows that the structure is able to withstand lateral loads up to its elastic limit, although there is a concentration of deformation on the ground floor. The potential for Soft Story and plastic hinges that form in several ground floor columns indicate the need for local strengthening to ensure the building remains safe against larger earthquakes in the future.