Dynamics of risers for earthquake resistant designs

Abstract

It is well known that no criterion about seismic design for risers is available, and relevant research has not been reported. A comprehensive study of riser dynamics during earthquakes is performed in this paper. A dynamic model for seismic analysis of risers is developed in accordance with the working environment of the risers and the infl uence of inertia force of the pipelines. The dynamic equations for the developed model are derived and resolved on the basis of the energy theory of beams. Numerical simulation for an engineering project in the Bohai Oil Field, China shows that the fundamental frequency of the riser plays the major role in the seismic responses, and for platforms in shallow water in Bohai Bay, the risers demonstrate a much lower stress response due to prominent differences between the riser frequency and the earthquake wave frequency. The presented model and its corresponding method for seismic analysis are practical and important for riser design resistant to earthquake waves.

Parametrically excited vibrations of marine riser under random wave forces and earthquake

“…Besides, most of oil/gas resources are in the Circum-Pacific seismic belt, the most active seismic zone in the world; the effect of earthquake may be very significant. It is noted (Duan et al, 2010) that 85% of the total amount of the earthquakes occurs in the ocean. Research on subsea risers in seismic conditions is one of the academic and engineering attractions in offshore engineering.…”

A review of floating semisubmersible hull systems: Column stabilized unit

“…Chakrabarti (2005) showed the types, usage and dynamics of drilling and production risers. Because risers are directly connected to wellheads or Blowout Preventers (BOPs), which are in direct contact with the seabed, not only they are affected by the structural response of the platform and ocean waves, but also they respond to seismic and earthquake conditions (Duan et al, 2010). The design of risers and subsea pipe structures is recorded in Bai and Bai (2005).…”

Dynamic Response Analysis of Cable of Submerged Floating Tunnel under Hydrodynamic Force and Earthquake

“…The design target acceleration response spectrum ( ) can be obtained in seismic design guidelines, which cannot be directly used by (6). Thus, a conversion formula is needed to obtain the corresponding ground motion power spectrum ( ).…”

“…It is noted by Duan et al [6] that 85% of the total amount of earthquakes occurs in the ocean. The Bohai Strait, the Qiongzhou Strait, and the Taiwan Strait in China are three potential areas to build submerged floating tunnels, which are also in the Circum-Pacific seismic belt.…”