Load Analysis of Offshore Steel Fixed Jacket Platform Structures Having Bracing Pattern

The present study evaluates the structural behaviour of an offshore steel fixed jacket platform with different bracing configurations using SAP2000. The analysis considers single bracing, double bracing and knee bracing at 0°, 20° and 30° inclinations. Based on the obtained results, the following conclusions are drawn: 1.        Bracing configuration has a significant effect on the dynamic and static performance of offshore jacket platforms. 2.        Knee bracing shows the highest first-mode time period, with a maximum value of 5.963801 sec, indicating comparatively flexible structural behaviour. 3.        Single bracing shows considerable improvement in stiffness when the bracing angle is increased from 0° to 30°, as its first-mode time period reduces from 4.24472 sec to 1.526913 sec. 4.        Base shear results show that single bracing develops the highest maximum base shear of about 2886.26898, while double bracing shows the lowest maximum base shear of about 1880. 5.        Natural frequency results indicate that double bracing provides higher frequency response in several modes, reflecting improved stiffness and better dynamic stability. 6.        Displacement results show that double bracing provides the least deformation in both X and Y directions. The Y-direction deformation for double bracing is 0.327 mm, compared with 0.544569 mm for single bracing and 0.4279 mm for knee bracing. 7.        Considering base shear reduction, displacement control and dynamic stability, double bracing is found to be the most efficient configuration among the studied bracing systems. 8.        The study confirms that proper selection of bracing pattern and bracing angle is essential for improving the structural integrity, safety and performance of offshore steel fixed jacket platforms.

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