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Abstrak :
The major problem in serviceability degradation of steel truss bridge is interaction of moving vehicle load with the bridge 's upper structure. One of the improvement efforts is to strengthen the bridge system by using eternal pretension tendon. Pretension tendons with polygonal, kingpost and horizontal configuration are designed as an active control equipped with the actuator. Based on adaptive control technique, fuzzy logic algorithm was used to activate the tendon control in the bridge as a Fuzzy Logic Control feedback ( FLC feedback) system, where the change of control force can be set to be proportionalbr adaptable to the displacement. From the simulation with various cable configurations, with various velocities of continuous and discontinuous vehicle models, and various types of tendons, it shows that the Kingpost tendon configuration has a better performance to reduce the displacement of the bridge 's upper structure and to minimize tensile stresses at bottom chord element.

Abstrak :
Analisis modal secara teoritis dan eksperimen dilakukan pada penelitian ini untuk mendapatkan parameter dinamik struktur, yaitu: periode getar, rasio redaman, dan mode getar. Objek struktur yang digunakan adalah Jembatan Teksas di Universitas Indonesia yang merupakan jembatan pedestrian tipe rangka baja sepanjang 84 m. Jembatan dimodelkan secara tiga dimensi dengan program SAP 2000 untuk mendapatkan periode getar dan mode getar jembatan secara teoritis. Free vibration test kemudian dilakukan untuk mendapatkan periode getar dan rasio redaman secara eksperimental. Pengukuran vibrasi menggunakan microtremor dengan sensor acceleration dan eksitasi berupa human induced vibration. Pada akhirnya eksperimen mampu mengidentifikasi empat dari lima mode pertama struktur utama jembatan. Periode getar dari hasil eksperimen menunjukkan hasil yang identik dengan periode hasil modelisasi dengan rata - rata periode hasil eksperimen lebih besar 15% dibandingkan periode hasil modelisasi. Berdasarkan hasil eksperimen rasio redaman jembatan didapat sekitar 2.2 %, hasil ini seusai dengan literatur yakni sekitar 2 - 3 %. ......Theoretical and experimental modal analysis were conducted in this study to obtain dynamic parameters of structure, such as: natural period, damping ratio, and mode shape. The object used is Teksas Bridge in Universitas Indonesia which is a 84 m long steel truss pedestrian bridge. The bridge was modeled in three dimensional using SAP 2000 to obtain natural period and mode shape theoretically. Free vibration test was then performed to obtain natural period and damping ratio experimentally. The structure excited by human induced vibration and then measured using microtremor with acceleration sensor. At the end, experiment were able to identify four of the five initial modes of major structure of the bridge. The natural period from experimental results showed identical results with the theoretical one, with experimental natural period 15 % average greater compared to theoretical natural period. According to experimental results, damping ratio of bridge were obtained about 2.2 % corresponding to literature which is about 2 - 3 %.