Indonesia terletak di pertemuan tiga lempeng tektonik utama, menjadikannya wilayah dengan aktivitas seismik tinggi. Kondisi ini menuntut bangunan memiliki ketahanan gempa untuk menjamin keselamatan penghuni dan keberlanjutan fungsi bangunan. Struktur beton bertulang. Namun, mutu beton rentan menurun karena proses pengerjaan di lapangan, seperti pencampuran, pengecoran, pemadatan, dan curing, berbeda dengan baja yang diproduksi di pabrik dengan mutu lebih terjaga. Penurunan mutu beton dapat memengaruhi kinerja struktur, khususnya saat gempa. Penelitian ini bertujuan mengevaluasi kinerja seismik gedung 8 lantai berdenah lengkung akibat penurunan mutu beton berdasarkan standar ASCE 41-17. Diamati perubahan gaya gempa, simpangan antar lantai, serta rasio strong column–weak beam. Hipotesis awal menyatakan bahwa penurunan mutu beton meningkatkan kebutuhan penulangan dan menurunkan kinerja seismik struktur secara keseluruhan.

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Indonesia is located at the convergence of three major tectonic plates, making it a region with high seismic activity. This condition requires buildings to be earthquake-resistant to ensure occupant safety and maintain structural functionality. Reinforced concrete structures are commonly used. However, concrete quality is vulnerable to degradation due to on-site construction processes such as mixing, casting, compaction, and curing—unlike steel, which is factory-produced with more consistent quality control. A decrease in concrete quality may significantly affect structural performance, especially during earthquakes.This study aims to evaluate the seismic performance of an 8-story curved-plan building due to reduced concrete quality, based on the ASCE 41-17 standard. Additionally, changes in seismic forces, inter-story drifts, and the strong column–weak beam ratio are observed. The initial hypothesis states that reduced concrete quality increases reinforcement demand and decreases the overall seismic performance of the structure.