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Offshore platforms in seismically active areas should be properly designed to survive within the face of intense earthquakes without a global structural collapse. This paper scrutinizes the seismic performance of a newly designed and established jacket type offshore platform based on the API-RP2A normalized response spectra during seismic events. A finite element model is developed from a typical jacket type offshore platform taking into the effect of the interaction among structure, pile, and soil components. The seismic responses of jacket type offshore platforms subjected to random earthquake excitations are evaluated by means of the power spectral density (PSD) analysis. Dynamic characteristics, the response function, output PSD and transfer functions for various elements of the platform are discussed. The spectrum compatible PSD is directly used to estimate the peak structural responses and determine the dynamic response of offshore jacket platforms that meet the required level of engineering practice for preliminary design.

Offshore platforms in seismically active areas should be properly designed to survive within the face of intense earthquakes without a global structural collapse. This paper scrutinizes the seismic performance of a newly designed and established jacket type offshore platform based on the API-RP2A normalized response spectra during seismic events. A finite element model is developed from a typical jacket type offshore platform taking into the effect of the interaction among structure, pile, and soil components. The seismic responses of jacket type offshore platforms subjected to random earthquake excitations are evaluated by means of the power spectral density (PSD) analysis. Dynamic characteristics, the response function, output PSD and transfer functions for various elements of the platform are discussed. The spectrum compatible PSD is directly used to estimate the peak structural responses and determine the dynamic response of offshore jacket platforms that meet the required level of engineering practice for preliminary design.

Offshore platforms in seismically active areas should be properly designed to survive within the face of intense earthquakes without a global structural collapse. This paper scrutinizes the seismic performance of a newly designed and established jacket type offshore platform based on the API-RP2A normalized response spectra during seismic events. A finite element model is developed from a typical jacket type offshore platform taking into the effect of the interaction among structure, pile, and soil components. The seismic responses of jacket type offshore platforms subjected to random earthquake excitations are evaluated by means of the power spectral density (PSD) analysis. Dynamic characteristics, the response function, output PSD and transfer functions for various elements of the platform are discussed. The spectrum compatible PSD is directly used to estimate the peak structural responses and determine the dynamic response of offshore jacket platforms that meet the required level of engineering practice for preliminary design.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures. The structural integrity of platform components under the maximum and minimum operating loads of environmental conditions is required for risk assessment and inspection plan development. In-place analyses have been executed to check that the structural member with all appurtenances robustness and capability to support the applied loads in either storm condition or operating condition. A nonlinear finite element analysis is adopted for the platform structure above the seabed and the pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The analysis includes interpretation of dynamic design parameters based on the available site-specific data, together with foundation design recommendations for in-place loading conditions. The SACS software is utilized to calculate the natural frequencies of the model and to obtain the response of platform joints according to in-place analysis then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have important effects on the results of the in-place analysis behavior. The result shows that the in-place analysis is quite crucial for safe design and operation of offshore platform and assessment for existing offshore structures.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures. The structural integrity of platform components under the maximum and minimum operating loads of environmental conditions is required for risk assessment and inspection plan development. In-place analyses have been executed to check that the structural member with all appurtenances robustness and capability to support the applied loads in either storm condition or operating condition. A nonlinear finite element analysis is adopted for the platform structure above the seabed and the pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The analysis includes interpretation of dynamic design parameters based on the available site-specific data, together with foundation design recommendations for in-place loading conditions. The SACS software is utilized to calculate the natural frequencies of the model and to obtain the response of platform joints according to in-place analysis then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have important effects on the results of the in-place analysis behavior. The result shows that the in-place analysis is quite crucial for safe design and operation of offshore platform and assessment for existing offshore structures.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures. The structural integrity of platform components under the maximum and minimum operating loads of environmental conditions is required for risk assessment and inspection plan development. In-place analyses have been executed to check that the structural member with all appurtenances robustness and capability to support the applied loads in either storm condition or operating condition. A nonlinear finite element analysis is adopted for the platform structure above the seabed and the pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The analysis includes interpretation of dynamic design parameters based on the available site-specific data, together with foundation design recommendations for in-place loading conditions. The SACS software is utilized to calculate the natural frequencies of the model and to obtain the response of platform joints according to in-place analysis then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have important effects on the results of the in-place analysis behavior. The result shows that the in-place analysis is quite crucial for safe design and operation of offshore platform and assessment for existing offshore structures.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures. The structural integrity of platform components under the maximum and minimum operating loads of environmental conditions is required for risk assessment and inspection plan development. In-place analyses have been executed to check that the structural member with all appurtenances has robustness and capability to support the applied loads in either storm condition or operating condition. A nonlinear finite element analysis is adopted for the platform structure above the seabed and the soil–pile–jacket interaction to estimate the in-place behavior of a typical fixed offshore platform. The analysis includes an interpretation of the dynamic design parameters based on the available site-specific data, together with foundation design recommendations for in-place loading conditions. The SACS software is utilized to calculate the natural frequencies, dynamic amplification factors, and the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have important effects on the results of the in-place analysis behavior. The incidence angle of seismic waves is an essential parameter, where, for some crucial angles, the internal forces and the maximum deformations can be doubled or more in comparison with the ones corresponding to other, less crucial angles. Therefore, the incidence angle considerably affects the response quantities. The results confirm that the in-place analysis is quite essential for the reliable design of new offshore platforms and the assessment of existing offshore structures.

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures. The structural integrity of platform components under the maximum and minimum operating loads of environmental conditions is required for risk assessment and inspection plan development. In-place analyses have been executed to check that the structural member with all appurtenances has robustness and capability to support the applied loads in either storm condition or operating condition. A nonlinear finite element analysis is adopted for the platform structure above the seabed and the soil–pile–jacket interaction to estimate the in-place behavior of a typical fixed offshore platform. The analysis includes an interpretation of the dynamic design parameters based on the available site-specific data, together with foundation design recommendations for in-place loading conditions. The SACS software is utilized to calculate the natural frequencies, dynamic amplification factors, and the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have important effects on the results of the in-place analysis behavior. The incidence angle of seismic waves is an essential parameter, where, for some crucial angles, the internal forces and the maximum deformations can be doubled or more in comparison with the ones corresponding to other, less crucial angles. Therefore, the incidence angle considerably affects the response quantities. The results confirm that the in-place analysis is quite essential for the reliable design of new offshore platforms and the assessment of existing offshore structures.