<![CDATA[Abstrak Pemantauan frekuensi alami pada jembatan box girder bentang 40 meter merupakan langkah penting dalam memastikan stabilitas dan keselamatan struktur selama kondisi layanan aktual. Penelitian ini menerapkan metode Stochastic Subspace Identification (SSI) covariance untuk mengidentifikasi karakteristik dinamis struktur berdasarkan respons getaran akibat beban operasional kendaraan yang melintas. Data diolah tanpa eksitasi buatan, sehingga mencerminkan perilaku dinamis jembatan secara realistis. Hasil analisis menunjukkan frekuensi alami yang stabil dan konsisten pada rentang 3,88–3,89 Hz, baik dari masing-masing sensor maupun analisis gabungan. Temuan ini konsisten dengan hasil pemodelan numerik, yang memperkuat validitas metode SSI covariance sebagai pendekatan non invasif dalam pemantauan kesehatan struktur. Pendekatan ini menegaskan frekuensi alami sebagai indikator utama dalam mengevaluasi kondisi struktural jembatan secara akurat dan andal di bawah beban operasional nyata. Kata kunci: SHMS, OMA, SSI covariance, Frekuensi Alami. Abstract Monitoring the natural frequency of a 40-meter span box girder bridge is essential to ensure the structural stability and safety under actual service conditions. This study applies the Stochastic Subspace Identification (SSI) covariance method to identify the dynamic characteristics of the structure based on vibration responses induced by operational vehicle loads. The data were processed without artificial excitation, thereby reflecting the realistic dynamic behavior of the bridge during operation. The analysis results indicate a stable and consistent natural frequency in the range of 3.88–3.89 Hz, observed across individual sensor measurements as well as in combined analysis. These findings are in good agreement with the numerical modeling results, strengthening the validity of the SSI covariance method as a non invasive approach in structural health monitoring. This approach emphasizes the role of natural frequency as a key indicator for accurate and reliable evaluation of bridge structural conditions under real operational loads. Keywords: SHSM, OMA, SSI covariance, Natural Frequency]]>
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