SEISMIC RISK ASSESSMENT AND RETROFIT IN PRESTRESSED CONCRETE BRIDGE WITH COMBINATION OF SIMPLY SUPPORTED BEAM AND FRAME SYSTEM BY USING INCREMENTAL DYNAMIC ANALYSIS
<p align="justify">One method to assess seismic risk is by using fragility curve. It is a curve which shows how the probability of collapse increases with the increasing of ground motion for certain damage level. In Indonesia, the most common bridges type and crucial to be assess is...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/31352 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | <p align="justify">One method to assess seismic risk is by using fragility curve. It is a curve which shows how the probability of collapse increases with the increasing of ground motion for certain damage level. In Indonesia, the most common bridges type and crucial to be assess is a prestressed concrete girder with a combination of simply supported beam and frame system. <br />
Analytical method is used in this study to create fragility curve where at first 3D model of bridge structure subjected with 10 different ground motion is scaled with target spectrum, and then magnifies the intensity (PGA) with constant scale until certain damage level. By using lognormal cumulative distribution function, then a fragility curve is made for bridge component and bridge system. A first order reliability bounds was used to estimate system failure under failure combination mode. Then a total probability of failure is calculated by using hazard curve and fragility curve. This total probability of failure is then evaluated by comparing it with the target reliability of the corresponding structures.<br />
Reliability index in each studied bridge system are 3.91 for existing bridge with probability of failure P(Collapse) = 4.6 x 10-5, 4.00 for frame system with probability of failure P(Collapse) = 3.2 x 10-5, 4.17 for existing bridge retrofitted with LRB or with probability of failure P(Collapse) = 1.6 x 10-5, 3.96 for existing bridge retrofitted with viscous damper or with probability of failure P(Collapse) = 3.7 x 10-5. All of the reliability index are higher than target reliability based on SNI 2833:2016 which is beta = 3.1. This indicate that bridge is designed conservatively and might be overdesign, due to smaller risk of failure than the corresponding target.<p align="justify"> |
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