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LimitState:RING

Industry leading masonry arch bridge analysis software

Trusted by major consulting engineers, bridge owners and universities across the world, LimitState:RING is the industry-leading software application for rapid masonry arch analysis, capable of modelling a wide range of potential failure modes in both single and multispan structures.

Version 4 combines the familiar LimitState:RING features and ease of use with a range of powerful new functions and enhancements.

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Interactively answer ‘what if’ questions to gain a clearer understanding of the influence of key parameters and see visualizations of modes of response - many of which are missed by conventional masonry arch bridge analysis tools.

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A Wide Range of Bridge Analysis Applications

Single-span bridges

Use LimitState:RING for a quick and easy single-span highway or railway arch bridge analysis. Problems can contain stone voussoir or brickwork arch barrels, either bonded and multi-ring. A range of predefined and user-defined arch profiles are available.

Multi-span bridges

With LimitState:RING the critical mode of response is identified automatically, whether this involves one, two or more adjacent bridge spans. Unlike other masonry arch software, there is no need to manually balance thrusts at pierheads.

Railway bridges

LimitState:RING was developed in association with the International Union of Railways (UIC) and ships with a database of rail vehicles. Axle loads are distributed through track / sleepers in accordance with industry practice.

Damaged structures

With LimitState:RING you can incorporate bridge-specific details into your arch bridge analysis, including defects such as localized mortar loss and zones with differing material properties.

Multi-ring arches

Ring separation in a multi-ring masonry arch barrel adversely affects bridge load carrying capacity. LimitState:RING can model the effects of full or partial ring separation, and the associated combined sliding / hinging modes of response.

Bridge diagnostics

LimitState:RING includes the ability to impose support movements. This provides a powerful diagnostic tool for investigating the causes of observed cracks and also for investigating the behavior of masonry arch bridges under service loads.

Reinforced masonry arches

LimitState:RING allows masonry arch bridges incorporating reinforcement to be modelled. Moment, shear and normal force diagrams can be displayed to help users interpret the response of reinforced masonry arch bridges.

Optional permissible limit state analysis

When a loading (traffic) regime changes, a bridge in good condition may degrade rapidly and become unserviceable. LimitState:RING optionally allows analysis of the permissible limit state, permitted by CS454 and described in CIRIA C800.

Software Benefits

Fast

Easy to use interface enables a bridge model with vehicle loading to be created in minutes, with analysis results typically available in seconds.

Powerful

Rigorous optimization is used to find the critical mode of response and margin of safety, whether single-span arch or complex multi-ring, multi-span viaduct.

Trusted

Developed by acknowledged experts in the field and validated against laboratory and field bridge tests.

Analysis Workflow

Use the "New Bridge Wizard" to rapidly specify the type of bridge being modelled (highway or railway), its geometry, material properties and the loading to be applied. Specify the values of any applicable partial factors.
This allows a preliminary bridge model to be set up, with (generally conservative) default values of parameters used in the absence of better information.t goes here
If necessary, select regions of the bridge with different material properties, or where there are localized defects, and specify appropriate properties via the "Property Editor".
This reduces the likelihood of a bridge being needlessly condemned because e.g. the arch thickness has been globally reduced to account for a local defect.
Set up a series of load cases to traverse a vehicle across the bridge and click Solve to determine the critical load position and associated factor of safety. Alternatively, use the software in "drag and solve" mode to quickly explore the response of the structure with the load at different locations.
The software comes complete with a built-in library of standard rail and road vehicles, with the option to also define bespoke loading vehicles that can be shared between users.
Unlike some traditional masonry arch bridge assessment methods, LimitState:RING users can quickly explore a large number of "what if?" scenarios, each time viewing the corresponding failure mechanism and building up a clear understanding of the likely mode of response and the key parameters influencing overall safety.
Automatically generate a PDF document containing all the relevant project information, including the computed load carrying capacity and an image of the associated failure mechanism.

Analysis Technology

LimitState:RING uses rigid block analysis, underpinned by rigorous Limit Analysis theory, to obtain solutions. The beneficial effects of backfill are also taken into account in the analysis. You can read more about how the method identifies the critical collapse mechanism in The Structural Engineer.

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How it works…

The user specifies the problem geometry, material properties and loading.
Masonry elements are modelled using rigid blocks, separated by contacts.
The anticipated effects of backfill are added to the model (e.g. load spreading).
The line of thrust and pattern of hinges are found using optimization, along with the corresponding margin of safety.