Prediction of Global Loads and Structural Response Analysis on a Multi-Purpose Semi-Submersible

2005 ◽  
Author(s):  
Yongwon Lee ◽  
Atilla Incecik ◽  
Hoi-Sang Chan
Keyword(s):  
Structural Response ◽  
Paper Analysis ◽  
Dynamic Loads ◽  
Response Analysis ◽  
Marine Structures ◽  
Flat Panel ◽  
Limit States ◽  
Static Loads ◽  
Wave Induced ◽  
Ultimate Limit

This paper presents analysis procedures of a prototype semi-submersible which consists of rectangular pontoons and square columns. The proposed semi-submersible is based on standard cubic boxes constructed by stiffened flat panel line assembly techniques. The prediction of global loads and responses is of great importance to engineers for assessing the safety of marine structures. In this paper analysis methods to determine the global structural loads and to assess the viability of the multi-purpose semi-submersible are described. Static loads in the still water condition and wave induced dynamic loads of cylindrical members in different design conditions were determined to investigate the viability of the proposed semi-submersible. Further the assessment of the safety against failure due to excessive maximum loads was accomplished in ultimate limit states.

Fragility Analysis Methods for Steel Storage Tanks in Seismic Prone Areas

2016 ◽  
Author(s):  
Hoang Nam Phan ◽  
Fabrizio Paolacci ◽  
Silvia Alessandri
Keyword(s):  
Seismic Vulnerability ◽  
Structural Response ◽  
Response Analysis ◽  
Seismic Demand ◽  
Fragility Functions ◽  
Storage Tanks ◽  
Demand Model ◽  
Limit States ◽  
Environmental Consequences ◽  
Fragility Function

Catastrophic failure of above ground storage tanks was observed due to past earthquakes causing serious economic and environmental consequences. Therefore, the evaluation of the seismic vulnerability of existing liquid storage tanks located in seismic prone areas is an important task. Seismic fragility functions are useful tools in order to quantify the seismic vulnerability of structures. These functions give a probability that a seismic demand on a structural component meets or exceeds its capacity, and are generally derived by a variety of approaches, e.g., field observations of damage, static structural analyses, judgment, or analytical fragility functions. Unlike the other methods, the analytical fragility functions are developed from a coupling of the structural response analysis and a probabilistic seismic demand model. The objective of this study is to investigate the seismic vulnerability of above ground steel storage tanks using different analytical methods of the fragility function. A comparison of the well-known cloud method and the incremental dynamic analysis is performed at different limit states for two existing cylindrical steel storage tanks. The first tank represents a slender geometry with a fixed-roof and the second one is a broad tank, unanchored, and provided with a floating roof.

Probabilistic Modelling for Reliability Analysis of Jackets

2004 ◽  
Author(s):  
Jan Mathisen ◽  
Knut O. Ronold ◽  
Gudfinnur Sigurdsson
Keyword(s):  
Reliability Analysis ◽  
Model Uncertainty ◽  
Failure Modes ◽  
Structural Response ◽  
Probabilistic Modelling ◽  
Extreme Waves ◽  
Limit States ◽  
Pile Capacity ◽  
Lateral Capacity ◽  
Ultimate Limit

Experience from recent reliability analyses of jacket platforms is used to discuss selected aspects of probabilistic modelling in more detail. These modelling details can have a significant effect on the computed reliabilities. An overview of basic considerations and failure modes in jacket reliability analysis is included to set the various details into context. Ultimate limit states for jackets in relatively shallow water are emphasised; i.e. quasi-static structural response is applicable. The following topics are considered: (a) Failure modes and some requirements to load and resistance analysis. (b) Directionality in loading and resistance. (c) Random periods of individual extreme waves. (d) Foundations — axial and lateral capacity modelling for multiple piles and model uncertainty for pile capacity.

Pull-Out Performance of T-Stub End Plate Connected To Concrete Filled Thin-Walled Steel Tube (CFTST) using Lindapter Hollo-Bolts

2018 ◽  
Vol 15 (1) ◽  
pp. 59
Author(s):  
NAZRUL AZMI AHMAD ZAMRI ◽  
CLOTILDA PETRUS ◽  
AZMI IBRAHIM ◽  
HANIZAH AB HAMID
Keyword(s):  
Limit Load ◽  
Steel Tube ◽  
Limit States ◽  
End Plate ◽  
Pull Out ◽  
Pullout Load ◽  
Thin Walled ◽  
Stub End ◽  
Concrete Filled Steel Tubes ◽  
Ultimate Limit

The application of concrete filled steel tubes (CFSTs) as composite members has widely been used around the world and is becoming popular day by day for structural application especially in earthquake regions. This paper indicates that an experimental study was conducted to comprehend the behaviour of T-stub end plates connected to concrete filled thin-walled steel tube (CFTST) with different types of bolts and are subjected to pullout load. The bolts used are normal type bolt M20 grade 8.8 and Lindapter Hollo-bolt HB16 and HB20. A series of 10 mm thick T-stub end plates were fastened to 2 mm CFTST of 200 mm x 200 mm in cross-section. All of the specimens were subjected to monotonic pull-out load until failure. Based on test results, the Lidapter Hollo-bolts showed better performance compare to normal bolts. The highest ultimate limit load for T-stub end plate fasten with Lindapter Hollo-bolt is four times higher than with normal bolt although all end plates show similar behaviour and failure mode patterns. It can be concluded that T-stub end plate with Lindapter Hollo-bolt shows a better performance in the service limit and ultimate limit states according to the regulations in the design codes.

The Mechanical Properties Comparative Analysis for Socked and Non-Socketed Composite Pile

2014 ◽  
Vol 1061-1062 ◽  
pp. 748-750
Author(s):  
Heng Chen ◽  
Ke Sheng Ma
Keyword(s):  
Mechanical Properties ◽  
Comparative Analysis ◽  
Seismic Performance ◽  
Dynamic Loads ◽  
Vertical Load ◽  
Interlayer Thickness ◽  
Static Loads ◽  
Soil Stress ◽  
Composite Pile ◽  
Static And Dynamic Loads

For socked and non-socketed piles in the different mechanical behavior under static and dynamic loads, the paper use ABAQUS to model, simulate the pile , the soil interlayer thickness between the bottom of the pile and bedrock are 2m, 4m under vertical load and Earthquake, cushion cap, pile and pile soil stress situation found non-socketed piles when the soil interlayer thickness within a certain range, the composite pile small subside under dynamic, static loads, the non-socketed piles can better take advantage of the pile soil has a good seismic performance in the earthquake.

Stability of offshore structures in shallow water depth

2011 ◽  
Vol 2 (2) ◽  
pp. 320-333
Author(s):  
F. Van den Abeele ◽  
J. Vande Voorde
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Fossil Fuels ◽  
Oil And Gas ◽  
Structural Response ◽  
Offshore Structures ◽  
Exploration And Production ◽  
Subsea Pipelines ◽  
Wave Induced ◽  
Shallow Water Depth

The worldwide demand for energy, and in particular fossil fuels, keeps pushing the boundaries of offshoreengineering. Oil and gas majors are conducting their exploration and production activities in remotelocations and water depths exceeding 3000 meters. Such challenging conditions call for enhancedengineering techniques to cope with the risks of collapse, fatigue and pressure containment.On the other hand, offshore structures in shallow water depth (up to 100 meter) require a different anddedicated approach. Such structures are less prone to unstable collapse, but are often subjected to higherflow velocities, induced by both tides and waves. In this paper, numerical tools and utilities to study thestability of offshore structures in shallow water depth are reviewed, and three case studies are provided.First, the Coupled Eulerian Lagrangian (CEL) approach is demonstrated to combine the effects of fluid flowon the structural response of offshore structures. This approach is used to predict fluid flow aroundsubmersible platforms and jack-up rigs.Then, a Computational Fluid Dynamics (CFD) analysis is performed to calculate the turbulent Von Karmanstreet in the wake of subsea structures. At higher Reynolds numbers, this turbulent flow can give rise tovortex shedding and hence cyclic loading. Fluid structure interaction is applied to investigate the dynamicsof submarine risers, and evaluate the susceptibility of vortex induced vibrations.As a third case study, a hydrodynamic analysis is conducted to assess the combined effects of steadycurrent and oscillatory wave-induced flow on submerged structures. At the end of this paper, such ananalysis is performed to calculate drag, lift and inertia forces on partially buried subsea pipelines.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

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