offshore jacket-type towers are steel structures designed and constructed in marine environments for various purposes such as oil exploration and exploitation units, oceanographic research, and undersea testing. in this paper a newly developed meta-heuristic algorithm, namely cyclical parthenogenesis algorithm (cpa), is utilized for sizing optimization of a jacket-type offshore structure. the a...

It is generally accepted that performance-based design has to be reliability-based. Seismic performance evaluation is based on nonlinear dynamics and reliability theory taking into account uncertainties during analysis. Considering the economic importance of jacket type offshore platforms, the present research aims to assess the seismic performance of offshore steel platforms. In this study, th...

in this paper, pile behavior embedded in layered soil deposits subjected to seismic loadings is analyzed using a nonlinear fiber element for simulation of soil – pile interactions. in the created model, both pile and surrounding soil are modeled using fiber elements in a practical beam on nonlinear winkler foundation (bnwf) concept. herein, the features of drain–3dx finite element software are ...

Most of oil and gas offshore platforms are located in the seismic regains. So, Seismic vulnerability evaluation of the offshore platforms is one of the most important and vital issues in the structural systems. In this study, jacket type offshore platforms are studied by incorporating the pushover analyses and nonlinear time history analyses, in such a way that, first some push over analyses ar...

Considering the stress cycles in the joints and members due to wave induced forces on offshore platforms, fatigue analysis is therefore one of the most important analyses in the offshore platforms design. Although most of the steel jacket type platforms are designed and located in areas with relatively high ratios of operational sea-states, for maximum environmental events, would have acceptabl...

In the present climate of growth in bandwidth-hungry telecommunication applications, wireless infrastructure providers are under continuous pressure to exploit the limited radio spectrum as efficiently as possible. In this context, highaltitude platforms (HAPs) are increasingly being cited as having an important role to play in future systems and applications. They have the potential to exploit...

In this paper we present a taxonomy for distribution architectures of synchronous groupware. As demonstrated by our own groupware platforms DreamTeam and QuickStep, a certain architecture may be a suitable for one scenario, but may have many disadvantages in another scenario. Former taxonomies divide distribution architectures into centralized, replicated and hybrid ones. Such a classification ...