FATIGUE RELIABILITY EVALUATION OF THE CABLE-STAY BRIDGE UNDER MOVING VEHICLES LOAD (CASE STUDY OF THE MERAH PUTIH BRIDGE, AMBON-MALUKU)
The cable in cable-stayed bridge is one of the main components that work to receive loads. One of these loads is vehicle load. Vehicle loads provide repetitive or cyclic loads that will create a fatigue hazard. In the design process of cable-stayed bridges, the fatigue hazard of cables is a major co...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/53784 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The cable in cable-stayed bridge is one of the main components that work to receive loads. One of these loads is vehicle load. Vehicle loads provide repetitive or cyclic loads that will create a fatigue hazard. In the design process of cable-stayed bridges, the fatigue hazard of cables is a major concern. This study aims to determine stress of cables and fatigue reliability of the cables. This study uses AASHTO, SNI and weigh-in-motion (WIM) loads as the basis for the fatigue loading analysis. HS20-FTG loads according to AASHTO LRFD and Truck T according to SNI 1725 2016 are used as check for fatigue limits on bridge design. WIM load is used as representation of the actual condition of the vehicle load was working on the bridge. The WIM data using Kendal-Pantura road section with duration of data collection for 1 month (1 October 2018 to 4 November 2018). The WIM data was downloaded from the sinerjiteknoindo.com site which was recorded by Pusjatan-PUPR.
This study uses the Merah Putih Bridge as the object of research. The Merah Putih Bridge has main span length of 300 m, pylon height of 89.50 m, and total width of 21.50 m with configuration of 2 lanes and 2 lanes per lane. The bridge was modeled with Midal Civil software. The output of the model will get the cable stress due to random vehicle loads. Cable stress from random vehicle loads was statistically processed with Microsoft Office Excel 365 and EasyFit software to obtain statistical parameters of the cable stress distribution. SN curves used in determining fatigue life are obtained from several literatures. The statistical parameters and SN curve are used to determine the fatigue reliability of the cables.
The analysis result shows that the cable is suspected fatigue found on cable 1680 (M1 position) with a mean stress of 667.27 MPa and a varies stress at 64.78 ~ 155.72 MPa with beta distribution value of ?1 = 11,239, ?2 = 162.78, a = 47,359 and b = 874.33. The cable fatigue life has the lowest value in the analysis using the Wokem SN curve (A416-270 12.70 mm) with 8.49 + 07 cycles for conditions without integral lower bound and 1.34E + 09 cycles with integral lower bound. The highest probability of failure of cable 1680 is found in the 1-a model. Assuming the Merah Putih Bridge vehicles in Ambon are 50% reduction from Jalan Pantura - Kendal, for 75 years life design, the risk of fatigue failure is obtained at value of Pf = 2.43E-05 or safety index ? = 4.063. This value is still at the safe limit, where the safety index target value according to AASHTO is 3.50.
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