Analisis Faktor Pembesaran Dinamik Pada Jembatan Rangka Baja Dengan Menggunakan Aplikasi Phyphox Dan Simulasi Software Midas Civil

Abstract

Steel truss bridges are critical structures that are vulnerable to repeated dynamic loads caused by vehicular traffic. The effects of such dynamic loads require special attention in design, particularly because resonance can occur when the excitation frequency approaches the structure’s natural frequency, increasing the risk of damage. This study aims to analyze the natural frequency and Dynamic Amplification Factor (DAF) of the Sei Belawan Steel Truss Bridge through experimental and numerical approaches. Field measurements were conducted using the Phyphox application on a Vivo Y21T smartphone, utilizing its accelerometer to record acceleration responses due to traffic loads. The data were analyzed using the Fast Fourier Transform (FFT) method in OriginPro to obtain the dominant frequency. Numerical simulation was performed using MIDAS Civil software with finite element modeling to determine the natural frequency of the structure. The results showed that the dominant frequency from field measurements in the Z-direction was 2.742 Hz, while the natural frequency obtained from simulation was 2.412 Hz, with a difference of 13.68%. The maximum DAF was recorded at 3.33 with a frequency ratio of η = 1.13, indicating the occurrence of resonance and a significant amplification of the dynamic response