Modelling Missing Masonry Blocks
In LimitState:RING, is it possible to generate a model with a specified group of bricks missing?
The answer is yes - by following the method outlined below:
- Select the blocks that you wish to remove and, using the Property Editor, set their 'Unit Weight' to zero.
- Select the radial contact surfaces between and at either end of the blocks that you wish to remove and set the 'Enabled' option to false.
- Select the tangential contact surfaces above the blocks that you wish to remove and 'glue' these to the upper ring of masonry by setting the 'Permit sliding' and 'Permit hinging' options to false.
- Select the tangential contact surfaces above the blocks to either side of those that you have removed and set 'Permit sliding' and 'Permit hinging' options to false - this prevents the arch being unstable under the action of dead loading.
Following this course of action, the thrust lines will not display correctly after solving. You should therefore hide them by clicking the 'Show / Hide Thrust' button in the View toolbar (normally 3rd button from the bottom on the left of the screen).
Also, as a post-analysis check, you should ensure that the normal and shear forces are zero around the areas of the removed blocks.
This example file includes a model where the 4 crown blocks have been removed from the intrados ring using the method described above: