Software Tour
Loading Types and Load Combinations
Loading Types
LUSAS provides a comprehensive range
of loading types to cater for most circumstances. Loading types
include:
- Structural loadings include concentrated,
body force, distributed, face, temperature, stress/strain, and
beam loads.
- Prescribed
values can specify initial displacements, velocity or
acceleration at a node.
- Discrete
loads are used to distribute a given loading pattern over full or
partial areas of the model, independent of the model geometry.
Point and Patch loads are discrete loads - also known as general
loads.
- Thermal
loads to describe the temperature or heat input to a thermal
analysis.
Structural, prescribed and thermal
loads are feature based loads that are assigned to the model geometry
and are effective over the whole of the feature to which they are
assigned. Discrete loads are feature independent. Variations
in loading can be applied to all feature load types according to the
feature on which they have been assigned.
Vehicle Loading
Comprehensive
vehicle and general loading facilities make load generation very straightforward, significantly
speeding-up the task of defining the loading on a bridge deck. LUSAS Bridge provides
static vehicle loading options for many worldwide bridge design
codes. These loadings can be used either on their own or with a moving load generator.
Moving vehicle/train load generators can be
used to automatically
generate the
required loadcases for a vehicle as it tracks across a bridge.
For special heavy vehicles, an Abnormal Indivisible Load generator is
included which can generate the load pattern for all possible combinations of
vehicles/axle load/axle spacing.
An optional Vehicle
Load Optimisation facility allows an optimised load
pattern to be generated in accordance with the chosen code of practice.
As well as vehicle loadings, a wide range of
structural, prescribed (initial displacement, velocity,
acceleration), discrete and temperature loadings can be applied.
Static Vehicle Loading
Static vehicle, lane, and knife edge loading
types are provided for many regional codes of practice. These
currently include: AASHTO LFD & LRFD
(USA), BD21/97 (UK), 21/01 (UK), BD37/88 (UK), 37/01
(UK), BRO94 and BRO2002 Vehicle and Classification loads and BRO Train
loading (Sweden), Korean, Israel, Norway, HK (Hong
Kong), Australia, China, Eurocode vehicle and train loading, Finland,
India, New Zealand, Poland and South Africa (coming in V14.3). Additional loading types are being added all the time.
Vehicle Load Optimisation
Significant amounts of time can be saved with the optional
Vehicle Load Optimisation facility
which generates the worst combination of live loading. The interface consists of a series
of dialogs requiring only the input of a few parameters to enable the
optimised load
pattern to be generated in accordance with the chosen code of practice.
Single and Multiple Stage Prestress and Post Tensioning
Single and multiple
tendon prestress wizards calculate equivalent nodal loading due to
tendon prestressing or post-tensioning and assign these forces
automatically to beam, plane stress or solid elements of the model for
the current active loadcase. Computation
of tendon forces can currently be carried out in accordance with
AASHTO-LRFD, BS5400, Eurocode EN1992 and JTG D62-2004 design codes.
- The ability to input many hundreds of
tendons in one analysis that can be assigned to many hundreds of
loadcases is made easy by the use of the multiple stage prestress
wizard. Through a series of dialogs, the wizard simplifies the
definition of tendon profiles and properties.
- Elastic shortening losses can be
specified for multiple stressing stages – useful for staged
construction. Locally defined tendon profiles can be used anywhere
in the model and any number of times. One very useful feature allows
the tendon profile to be viewed in real-time as it is defined.
Tendon material properties including short and long term losses can
be specified.
- The tendon can then be easily assigned
to one or more line features on the model and, more importantly, to
one or more loadcases at the same time.
Load Combinations
 A key feature of LUSAS Bridge
is the
Basic, Smart and Code-specific load combination facilities which allow manual or fully
automated assembly of design load combinations. From these, envelopes, contour and
deflected shape plots, and results graphs can be readily obtained for any loadcase under
consideration.
- Basic load combinations allow for manual definition of loadcases and
load factors.
- The Smart Combinations facility, unique to LUSAS Bridge,
automatically generates maximum and minimum load combinations from the applied loadings to
take account of adverse and relieving effects. This enables the number of combinations and
envelopes required to model a bridge to be substantially reduced. Absolute maximum
envelopes are included.
Load Combination Wizards use predefined bridge load
cases for country-specific design codes and help
automate the definition of load combinations for bridges. When used in conjunction with a
design code template, combinations of load combinations are automatically created to give
the resultant maximum and minimum ULS or SLS loadcases.
Back to Top
| Viewing
Results
|
|
Software Information
|
