Archie-M 2.7 release notes

Document history

  • 2025-07-04: First version, for 2.7.0-RC1

Introduction

Archie-M 2.7.0 will be released soon. Currently, a release candidate is available. If you would like to test this in preparation for upgrade, please contact support@obvis.com.

Autorun

Auto-running sets of loads is central to the Archie-M assessment workflow, so these are likely to be the most significant changes for users.

Assessment results are given in the presence of backing

If a bridge under assessment is modelled with no backing, Archie-M 2.6 and earlier will report OK (ie Pass) or Fail. Introduce backing to the model, and it won’t; the assessor is expected to inspect the results and judge whether the thrust position is acceptable. Archie-M 2.7 is much more helpful, reporting one of the following conditions:

  1. OK: the zone of thrust remains entirely within the masonry arch ring.
  2. Inspect: the zone of thrust passes into the masonry backing, but not into the fill.
  3. Fail: the zone of thrust passes into the fill.

This will allow the assessor to quickly focus on the cases that require judgement.

Colour coding of results

The results column is now colour coded.

Easy re-run of loads when the model is changed

When preparing an assessment, we often need to re-run the same set of loads as we iterate on a model. Until now, this has been slightly tedious, especially if the load set isn’t one complete family.

In 2.7, when an arch model is modified while the autorun dialog is open, this is detected, a warning message is shown, and a button is provided which will re-run the current load set.

Capturing auto-run results

The autorun dialog now has a button to copy the contents to the clipboard. The data are copied in tab separated format, so they can be pasted into Excel.

The graphical view

The following video demonstrates some new features of the graphical view.

Thrust excursion indicators

Archie-M 2.7 highlights where the zone of thrust escapes the masonry with a thick purple line. This is particularly useful in combination with thrust adjustment.

Stress indicators

Stress indicators (turn them on in the View menu) show the stress distribution implied by the thrust line assuming linear stiffness across the arch barrel, infinite compressive strength, no tensile strength. Note that none of these assumptions are valid, so these do not show an actual stress distribution, but they should help the user better understand what the thrust line means.

Thrust adjustment

Thrust adjustment was introduced to allow pier stability to be checked in multi-span assessment. It has other applications, however. It is now also available for single span models.

Any thrust adjustments applied are shown under each arch, and will be displayed in printed output. Thrust adjustment values are also included in the tabular results.

The behaviour should be more consistent and predictable. In particular, the thrust will no longer “jump” when the first adjustment is made, as the initial values are selected to match the default thrust.

Zoom improvements

Zoom behaviour is improved.

  • All zoom levels are relative to 100%, which fits the model in the available window space.
  • Holding control and using the mouse scroll wheel will zoom about the cursor.
  • Printed output will more reliably match the zoom state of the graphical view.

View menu changes

  • Stress indicators toggle is added.
  • The pier "kern" (middle third) lines are now off by default, but can be turned on in the View menu.
  • Pier segment marks are now available and on by default for consistency with the arch barrels.

Find worst position for load

The right click menu on a load gives the option to find the worst case position for that load. For multi-span structures, the choice is available to look for the worst case for a span, or for pier stability.

This uses the same algorithm as auto-run, but can be applied with other live loads in place.

The bridge wizard

The layout of bridge wizard remains largely unchanged, but there are some significant improvements in functionality.

  • When modifying an existing model, the wizard is tabbed, so it is easy to switch between pages as needed.
  • Changes to inputs are reflected in the displayed model, giving visual feedback, but if the wizard dialog is cancelled, all changes that have not already been applied are discarded.
  • The backing dialog is now included in the bridge wizard. This is partly for simplicity, and partly to require users to consider backing when setting up a bridge model. It is still possible to define a model with no backing, but this is rarely the correct thing to do.

The biggest changes are on the Arches page.

  • The displayed model is updated as soon as the required data are input, giving rapid feedback on the results of changes.
  • Quarter point rise is only editable when it is needed. If the shape is fully defined by a span and rise (as circular and elliptical arches are) then the calculated quarter point rise is reported back.
  • Spans can be added, removed, and re-arranged directly on this page.
    • Archie-M tries to do something sensible about pier top thickness and left hand x coordinates, but these values are readily edited if the results are wrong.
    • The pier width for multi-span bridges is included, as this makes building multi-span models easier.

Building a viaduct model is demonstrated in this video. Notice that the pier thickness is initially just enough to accommodate the rings without overlap, but once edited, the edited value is used when adding further spans. Modifying a pier width will update all span LHS.x values to the right: no more mental arithmetic.

On the "piers, abutments and fill" page, the pier top thickness is no longer editable, this must be edited on the Arches page.

Backing is added to the main bridge wizard.

  • The backing width setting is rarely needed. Since backing width 0 is never needed, this value is now interpreted to mean that backing should be projected forward to meet the arch ring.
  • Masonry strength for backing is not currently used, so it has been removed from the inputs.

Road

  • Road point lists can be edited more easily. It is still recommended to load road points from a file where there are more then three points.
  • A new piecewise linear road option is added, useful for modelling excavation.

Skew arch geometry

Skew arch handling is more complete.

  • The skew transform will now work for circular, elliptical, and three-centred geometry types. The skew option is disabled for other geometry types.
  • The extrados geometry is transformed properly.

This arch is a semi-circular on the square line, transformed to a 50 degree skew line:

Note that the arch, of constant ring thickness, gets thicker to the springing on the skew line.

Skew transformation can be used with multi-span structures, but the same transformation is applied to all spans, and the span LHS points are not updated. Span types for which the skew transform does not work in single span models will not be transformed. Use with caution.

True shape arch geometry

Users are encouraged to use defined arch shapes whenever possible. When it is not - when an arch is a shape that is not supported, or has distorted over time - the “true shape” geometry type accepts survey data.

The true shape input dialog will open the first time true shape geometry is selected for a model span. After that, the three dots … button can be used to open it.

The 2-tape input method for true shape data has been non-functional in recent versions of Archie-M. It now works.

Road handling

When a road surface (top of fill, surfacing, or overlay) drops below the top of the masonry (arch extrados or top of backing), the actual road surface will now follow the top of masonry. As a result, it is now easy to model bare arches: simply set a road level below springing level.

The existing multi-point "true shape" road option is now more robust.

A new "piecewise linear" road type is added. Combined with road surfaces following top of masonry, this makes it easy to model partial and asymmetric excavation of fill. Be careful when applying live loads over piecewise linear loads with steep or vertical segments, the load handling assumes smooth roads at relatively shallow slope.

The survey point positions for all road types are shown with small x marks. Where roads are extended beyond the outer survey points, the road surface is drawn in red.

The ribbon

A few tweaks have been made to the "ribbon" above the graphical view.

  • A red highlight now shows whether available width or effective width dominates for a given live load configuration (ie whether transverse distribution is limited by available width).
  • Distribution modes are now selected using a drop-down, as the list is longer.
  • The parameters for the Custom distribution mode can be set using the … button.

Interactive modification tools

Previous versions of Archie-M allowed interactive modification of mortar loss. This feature has now been extended to include more parameters.

  • Modify safety factors (from the Structure menu)
  • Modify Structure (from the Structure menu or right click on empty space)
    • Overlay depth
    • Available width
  • Modify arch (right click on the arch)
    • Mortar loss
    • Ring thickness
    • Backing height
    • Quarter point rise (only where the arch shape requires a quarter point rise input)

Passive pressure

Passive pressure handling in Archie-M 2.6 was incomplete. It would work as long as the assumed passive hinge position was correct. There was supposed to be an interactive element to this feature, but it wasn’t functional.

2.7 will find the passive hinge location by optimisation, remove the need for interactivity.

In this video, we see that the thrust curves more tightly than the arch. Archie-M 2.7 correctly finds the passive hinge location away from the springing, and demonstrates that limited passive pressure would keep the thrust in the arch.

Note: Passive pressure behind the abutment and backing is clearly an important part of the soil-structure interaction in a masonry bridge. Passive pressure behind the arch only really comes into play if you assume a level of backing rather lower than bridge builders would have dared provide.

New transverse distribution modes

Archie-M 2.7 makes some changes to the transverse distribution options.

  • “Railway” distribution has been renamed “Legacy Railway”. This distribution mode uses a reduced distribution below the top 300mm, which is inconsistent with 025. The results produced are conservative relative to the ‘025 specified distribution.
  • In place of Railway, the new distribution mode NR/GN/CIV/025 implements distribution as specified in '025, with 1:1 spread through all layers.
  • EN1991-2:2003 is provided, for completeness, because it has been requested by users. Note that this model of distribution is not intended for use with masonry bridges, and it is unreasonably conservative in most circumstances.
  • “Custom” distribution allows the user to specify a constant and a multiplier on depth for both transverse and longitudinal distribution. This is not intended for use in assessment, but can be useful in other circumstances.

In normal assessment work, use CS454 or NR/GN/CIV/025 modes.

Tabular ("intermediate") results

The tabular results are more comprehensive and better formatted. It is intended that they should contain complete input data, so a model could be recreated from the numerical output. If you find that this is still not so, let us know.

Table headings are more consistent, units should be given for all values.

Tabular results can still be copied to the clipboard and pasted into Excel. Where previously some cells contained both the value and the units, this should no longer happen.

The layout has changed, so spreadsheets built for results from previous versions will need to be adapted to the new format.

Reporting

Archie-M reports (Ctrl-P or File/Print) now include both graphical and numerical output. If you want report with one or the other, you can print page ranges to achieve this.

Refinements to the on-screen presentation of graphical and tabular results are reflected in the printed version too.

In addition, the printed graphical output has been refined:

  • Where "notes" are set, these will be displayed on the drawing output.
  • Layout of the printed graphical output is improved.
  • The graphical output included in a report reliably respects the zoom state of the graphical view.
  • Thrust adjustment values are now shown in printed output.

Standard loads

The load file folder has been cleaned up. The old AWR load files have been removed.

Wheel versions of the CS454 loads have been added, for use in assessing narrow strips of bridge, such as widenings. The appropriate available width will depend on the choice of wheel or axle load.

A bug in the SV loads has been fixed, in which a tractor axle load had been divided by 2 as if it were a wheel load.

As before, the derivation of the standard loads is set out in a pdf document beside the load file. Look in the installation folder, in the Load subfolder.

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