Civil and Structural engineering

Software Tour

Analysis capabilities

Analysis capability is dependent upon the product in use. The analysis capabilities of particular LUSAS Civil & Structural software products can be extended by using software options. For details see the Software Specifications.

Unrivalled state-of-the-art element libraries, isotropic and orthotropic material models in LUSAS Civil & Structural, allow all types of civil and structural engineering problem to be solved. 

Multiple analysis and branched analysis

When designing your structure, more than one type of analysis can be defined and solved independently from within one model using the multiple analysis and branched analysis facilities. This means that, in most cases, there is no need to create separate models and maintain clone copies of a model, in order to analyse and view results for different analysis requirements.

Analysis branches allow the creation and solution of one or more sub-analyses to investigate the response of the model at a particular loadcase or "stage". Use analysis branches to:

  • Carry out a linear moving load analysis of construction equipment during each stage of the construction.
  • Perform an eigenvalue natural frequency analysis or a buckling analysis during construction.
  • Perform a phi-c reduction analysis to derive safety factors for a geotechnical model from each stage in an excavation process.
  • Perform an earthquake analysis where gravity is applied in a static nonlinear step, then the earthquake is run as a transient branch. Several sample earthquakes may be run in each branch.

Linear static

Stresses, strains, displacements, moments, shears and axial forces that result from static loading are easily calculated, displayed and output from any model. Loads are assumed to be applied instantaneously in order to develop the state of internal stress and transient effects are ignored.

Cable tuning analysis

The cable tuning analysis facility calculates load factors for cables in order to achieve defined target values set for various feature types or results components. An 'exact' method, an optimisation facility and two best-fit solution methods are provided.

Target values analysis

The target values facility is a post-processing tool that provides a general method of varying load factors in a linear analysis to try and achieve target values defined for particular feature types or results components. The target values loadset created is similar to a combination, but the load factors are automatically calculated by the program in response to the defined targets.


LUSAS carries out elastic critical buckling, which is required for the calculation of member resistances. Often it is also required by some codes to determine if a second-order analysis needs to be carried out. If so, a full nonlinear buckling analysis can be undertaken.

  • For structural assessment, detailed buckling analysis with LUSAS can often reveal additional ‘hidden’ capacity and prove load capacity.

  • For new structures, linear and nonlinear buckling analysis using LUSAS can investigate girder stability during erection, look at the effects of a slab casting sequence, and also help to optimise the size of the web and flange plates, bracing, stiffeners and position of any temporary supports used.


Fatigue calculations can be carried out using the total life approach. Fatigue life may be expressed in terms of the damage that is done to the structure by a prescribed loading sequence or as the number of repeats of a sequence that will cause failure


LUSAS Civil & Structural excels in solving seismic and general dynamics problems. The natural frequency of structures, the effect of dynamic loading, such as crowds in sports stadiums and auditoriums, structural response due to earthquake or impact loading, and blast loading can all be readily assessed.

Mode 48 - Horizontal in the model Y direction (1.62Hz)

Interactive Modal Dynamics (Modal superposition)

Interactive Modal Dynamics (IMD) allows the natural vibration behaviour of a structure to be combined with a loading regime in order to calculate the dynamic response of a structure to a range of applied excitations. IMD produces results an order of magnitude faster than traditional time-step solutions. Multiple and more advanced loading events (including moving loads and nonlinear behaviour) can be modelled with the IMDPlus and additional software options.


LUSAS Civil & Structural handles geometric nonlinearity, material nonlinearity and contact nonlinearity to accurately model the structural behaviour. Local and global nonlinear analysis with LUSAS helps ensure that structures are designed economically and safely for any imposed loading. Automatic nonlinear solution procedures simplify the analysis process for applications such as:

  • Time-dependent dynamic analysis

  • Lift-off of bearings and halving joints

  • Bearing analysis

  • Elasto-plastic large deflection plate buckling

  • Concrete cracking

  • Concrete creep with recovery

  • Thermal loading

  • Impact / collapse assessments

  • ‘Push-over’ analysis

  • Excavation and construction

  • Soil-structure interaction

P-Delta analysis

P-Delta analysis is available for bar, beam, thick and thin shell, and 2D and 3D continuum elements with GNL capability. P-Delta analysis is an approximate geometrically nonlinear (GNL) analysis typically used to take account of the interaction between vertical and horizontal (sway) loading on tall, slender buildings. Vertical constant loads (usually dead loads) are used to form the geometric stiffness (stress stiffened) matrix for the structure; additional live load cases can then be applied and load combinations used to capture the effects of the interaction between lateral and vertical loading.

Thermal / Field analysis

The Thermal / Field software option contains extensive facilities for both simple and advanced steady state, and transient thermal / field analyses. By combining the LUSAS Thermal / Field option with other appropriate LUSAS options, heat transfer due to conduction, convection and radiation can be analysed. In addition, the effects due to phase change of material may also be included.  

For large concrete structures such as cooling towers, dams, caissons and other large foundation bases, steady state and transient thermal analyses can be done with or without thermal-structural coupling. Modelling of heat of concrete hydration can be done for a variety of cement types using the using the Heat of Hydration option.

Heat of hydration

Modelling of heat of concrete hydration can be carried out for a variety of cement types using the using the Heat of Hydration software option. Effects due to the addition of fly ash and ground granulated blast furnace slag can also be included. 

When used in conjunction with Nonlinear, Dynamic, and Thermal software options the heat of concrete hydration can be computed during a thermo-mechanical coupled analysis and the temperatures and degree of hydration can be read in to the mechanical analysis.

Heat of Hydration analysis

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LUSAS is a trademark and trading name of Finite Element Analysis Ltd. Copyright 1982 - 2022. Last modified: March 09, 2023 . Privacy policy. 
Any modelling, design and analysis capabilities described are dependent upon the LUSAS software product, version and option in use.