Paper presented at Gastech Exhibition and Conference, Milan, Italy, 5-8 September 2022 by Jesus Rodriguez of LUSAS.

This paper describes an efficient design approach for LNG storage tanks that adopts a 2D axisymmetric model for thermal analysis, and a 3D shell model for structural loads, considering seismic effects. This requires an integrated methodology extending to the combination of results and design checking, with detailed attention to the varying reinforcement orientation.

Methods have been developed based on the requirements of ongoing LNG tank projects for companies such as KOGAS (Korea Gas Corporation) and KGT (Korea Gas Technology Corporation). These enable all the required design checks to be performed in a single 3D shell model bringing together results from thermal, seismic, and staged construction analyses and allowing design checks performed to various international standards. 

LUSAS finite element analysis software was used to develop the required tools to automate the modelling and design of the storage tanks. Customisation and automation through an open API enables users with basic programming knowledge to create the various user defined features required, extract results and combine them with speed and accuracy in the desired format.

Solutions to the challenges encountered have enabled improvements in the efficiency of the analysis and design process for LNG storage tanks to reduce the engineers time and time to market by an estimated 20-30%.

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Paper presented at IABSE 2019, New York, USA, 4-6 Sepetember 2019 by Terry Cakebread of LUSAS.

This paper compares the traffic loading requirements and effects according to AASHTO 8th LRFD (used directly by 26 States) and four sample states that include amendments to that code, namely Kentucky, Maine, New York and Pennsylvania, against those obtained from international codes of practice including Eurocode EN 1992-1:2003, UK National Annexe (SV80 loading), Swedish Complementary Load Model, Canada CSA S6-14, Australia AS5100.2-2017 and China JTH D60-2015.

Paper presented at NASCC 2019, St Louis, Missouri, USA, 3-5 April 2019 by Terry Cakebread and Steve Rhodes of LUSAS.

This paper contrasts the different approaches to member resistance calculations in AASHTO 8th edition, Eurocode EN1993-2:2006 and Canadian Bridge Design standard CSA S6-14. An example steel truss footbridge is used to compare resistances and utilizations determined from each Code (on the basis of identical loading). AASHTO is found to be lacking two interaction checks, to be unconservative in one check and over-conservative in another by comparison to the Eurocode – and prohibits the use of some members based on slenderness alone. For its part, the Eurocode is found to be more opaque in expressing one interaction check and to be considerably more voluminous in the calculations required to obtain similar results.

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Paper presented at the 40th IABSE Symposium (Nantes 2018), Nantes, France, 19-21 September 2018 by Philip Icke and Steve Rhodes of LUSAS.

Describes and shows analysis techniques for 2D modelling of cracking and crushing in arches, investigating ring separation, and modelling repairs using dowels in arches to aid with general bridge management. Soil-stucture interaction modelling is discussed prior to showing how 3D solid models and layered shell elements can be used in conjunction with a trilinear soil model to investigate more detailed models that may also include internal spandrel walls.

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Paper presented at the 8th World Congress on Joints, Bearings and Seismic Systems, Atlanta, Georgia, USA, 25-29 September 2016 by Terry Cakebread of LUSAS.

Describes and illustrates the different ways that joints, bearings and seismic systems can be modelled, covering the relevance of using different finite element joint models in differing situations, These include different ways to model lift-off behavior (smooth contact or elastic-plastic joints); the use of more advanced joints for modeling lead rubber bearings and friction/pendulum bearings; why dampers and other seismic systems are employed and the methods of modeling them; and some more detailed bearing models including carrying out bearing repairs in situ and ways of modelling detailed bearing models with full contact behaviour.

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Paper presented at the International Bridge Conference 2014 by Steve Rhodes and Terry Cakebread of LUSAS.

At the time of writing the paper, no standard approach for the analysis of integral bridges appears in AASHTO LRFD Bridge Design Specifications or other international codes. This paper considers the approaches most suitable for modeling common integral bridge forms, expanding upon recent guidance regarding soil-structure interaction approaches. Issues including material properties, initial stress state and the incorporation of the effects of soil ratcheting are discussed and both continuum and spring-type finite element models are explored.

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A similar presentation for a paper presented at the European Bridge Conference in 2015 referencing metric units can also be viewed here.

Paper presented at the International Bridge Conference 2013 by Stephen Rhodes and Terry Cakebread of LUSAS.

Describes how Finite Element (FE) analysis can be used to predict buckling modes, highlighting methods which are practical for day-to-day use.  It explores some criterion which might be used to identify if such behavior, including global buckling modes, should be of concern to the designer, drawing on recommendations including those in the recently published NCHRP Report 725 and Eurocodes.  Use of FE in the determination of member resistances is also explored.

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Paper presented at 7th New York City Bridge Conference 2013 by T. Cakebread and S. Rhodes of LUSAS.

Describes how Finite Element (FE) modeling techniques can assist in the assessment (rating) and upgrading of steel bridges of various types. Global and local modeling options are considered with reference to several projects, in particular the West Gate Bridge in Melbourne, Australia. The use of different analysis assumptions, element types, eigenvalue and nonlinear analysis functions to achieve greater load rating capacity is outlined, identifying examples of good practice and drawing on international codes and literature for recommendations.

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As presented at IABSE 2013 by Philip Icke and Steve Rhodes of LUSAS.

This paper describes how Finite Element (FE) modelling techniques can assist in the assessment (rating) and upgrading of steel bridges of various types. Global and local modelling options are considered with reference to several projects, in particular the West Gate Bridge in Melbourne, Australia. The use of different analysis assumptions, element types, eigenvalue and nonlinear analysis functions to achieve greater load rating capacity is outlined, identifying examples of good practise and drawing on international codes and literature for recommendations.

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As presented at a workshop session at NASCC (incorporating the World Steel Bridge Symposium) 2012 by Terry Cakebread of LUSAS.

The assessment or load rating of existing structures to requirements is often over-conservative and can suggest they can "fail" buckling checks, but analysis with software can often reveal additional capacity. For new structures, where buckling during erection could be critical, FE analysis permits additional checks to be carried out. For existing and new structures, material and additional bracing/stiffeners can be optimised by carrying out FE analysis. See how this is done using LUSAS FE software.

As presented to the AASHTO T-19 Technical Committee in 2012 by Terry Cakebread of LUSAS.

This presentation considers the different modelling approaches used for different bridge types; the types of analyses involved; why a 3D model may be required; and what is involved in building and solving such a model

As presented at IABMAS 2012 by Philip Icke of LUSAS and Carlo Margheritti of LUSAS (Italia).

Structural analysis has progressed a long way from hand calculations and from when distribution factors first started to be used. From the first computer methods, grid and grillage analysis techniques evolved, leading through progressive enhancements to the advanced 3D graphical and analytical tools that we see and use today. Finite element (FE) modelling and analysis is being used more for bridge engineering because of the more economical and accurate assessments and designs its use produces. This paper illustrates the role that it can play in just some areas of bridge analysis, assessment and design with reference to bridge assessments and designs carried out by consultants on projects around the world.

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