MURUS

Masonry

MURUS provides the verifications described in the code SIA266, chapter 4.3 concerning structural safety and chapter 4.4 concerning serviceability, both for unarmed masonry. That frees the user from the cumbersome selection of the correct diagram and from the time-consuming interpolation between curves.

MURUS serves also as postprocessor for the building module of CEDRUS. It carries out the verifications for all brick walls for a series of selectable loading combinations.

Please note: Due to the exclusive support of SIA standards, the program is only offered in German and French.

User interface

All necessary parameters are concentrated in one input mask, which can handle a list of different walls and for each of them a list of loadings.

Parameters defining the geometry of a wall

The coordinate system and the geometry of a wall are defined as follows:

l_w		wall length
h_w		wall height
t_w		wall thickness
a/t_w		Degree of embedding of the ceiling (1.0 = full clamped)
h₀		layer height

Support types

The rotation at the top and foot of a wall can be free or fixed.

Types of masonry

MURUS offers an extendable list of the established types of masonry with all the needed properties.

Loadings

According to the support type it is possible to specify a lateral excentricity for the normal force or a prescribed rotation at the top and/or bottom of a wall.

Verification of bearing capacity

Verification of normal force

MURUS doesn't utilize the diagrams of the SIA266 code but rather carries out a nonlinear calculation based on the same moment-curvature characteristics used for creating the diagrams in the code and accounting for second order effects. This leaves more freedom in choosing the boundary conditions and eliminates interpolation inaccuracies. It furthermore yields the t_nom for the verification of shear that otherwise has to be assumed to a conservative 1/4 of the thickness of the wall.

Verification of shear

The procedure makes use of the t_nom supplied by the preliminary verification of normal force. It then tries to find the stress fields for the verification of shear. The solution is not unique as long as the bearing capacity is not reached.

Lateral loads

Lateral loads are assumed to be transferred in vertical direction only. They are included in the calculation model for the verification of normal force and therefore act together with the normal forces.

Carrying capacity

It is possible to evaluate the carrying capacity factor λ, by which a variable loading [N_x, V, M_z1, q_z]_Delta can be multiplied after successfully applying a constant loading [N_x, V, M_z1, q_z]_Base until the ultimate limit state is reached.

Verification of serviceability

Verification of crack widths

The procedure starts with the calculation of the deformation of the wall subjected to quasi permanent loads. If a state of equilibrium is found the edge strains εr(x) can be calculated from the curvature κ(x) of the deformed wall.
The maximum crack width is then evaluated as follows:
r_max = εr_max * h0 (h0 = layer height)

The calculation procedure allows to include lateral loads qz and thus respects also point 4.4.4 of the SIA266.

Verification of shear

For the verification the claculative values of the interstory drift v and the edge tension strain εx_max according to the formulas 17,18 of the SIA266 are compared with the admissible values listed in table 9 or with given limit values.

What was new in the former generations of MURUS

The collected changes compared to the predecessor generation are listed here.