Unreinforced Clay Masonry in Bending

The following example demonstrates how the bending capacities of an unreinforced clay masonry wall can be calcualted based on desing information provided by the engineer.

Import Modules

We start by importing the Clay() object.

from toms_structures.unreinforced_masonry import Clay

Create Masonry Object

We next define the masonry properties. Note, toms-structures is intended to be unit specific, entering units other than those specified by a particular parameter may lead to incorrect results.

fuc = 10  # unconfined compressive strength in MPa
mortar_class = 3  # mortar class
height = 2000  # height in mm
length = 2000  # height in mm
thickness = 90  # thickness in mm
bedding_type = True  # Whether the masonry is face-shell bedded or fully bedded
hu = 130  # height of the masonry unit in mm
tj = 15  # Grouth thickness between masonry units in mm
raking = 5  # joint raking in mm

With the properties defined, the Clay() object can be created.

wall = Clay(
    length=length,
    height=height,
    thickness=thickness,
    fuc=fuc,
    mortar_class=mortar_class,
    bedding_type=bedding_type,
    hu=hu,
    tj=tj,
    raking=raking,
    verbose=True,
)

Properties
==========
length: 2000 mm
height: 2000 mm
thickness: 90 mm
bedding_type: Full bedding
mortar class: M3
fuc: 10 MPa
fmt: 0.2 MPa
Joint thickness tj: 15 mm
Masonry unit height hu: 130 mm
Raking depth: 5 mm

Compute Horizontal Bending Capacity

Next we will compute the horizontal bending capacity of the wall in accordance with the method given in Cl 7.4.3 of AS 3700:2018. To do this, there are 2 parameters to be entered. For this example, we assume there is a 50KN UDL acting ontop of the wall and that the section we are checking is masonry to masonry.

fd = 50 / (thickness *1e-3) * 1e-3 # Minimum design compressive stress on the joint under consideration in MPa
interface = True # True for masonry to masonry shear plane

We can now use the horizontal_bending() method to calculate the bending capacity of the section

wall.horizontal_bending(fd=fd, interface=interface, verbose=True)

Horizontal Bending Capacity, refer Cl 7.4.3.2 AS3700
====================================================
fmt: 0.2 MPa
fd: 0.5555555555555556 MPa
kp: 1 Cl 7.4.3.4
fmt = 0.2 MPa (at interface with masonry)
Zd (horizontal): 2133333.3333333335 mm3
Zu (horizontal): 2700000.0 mm3
Zp (horizontal): 2133333.3333333335 mm3
Mch_1: 4.33 KNm Cl 7.4.3.2(2)
Mch_2: 2.29 KNm Cl 7.4.3.2(3)
Mch_3: 0.71 KNm  # Cl 7.4.3.2(4)

Horizontal bending capacity:
Mch: 0.71 KNm for height of 2000 mm
Mch: 0.35 KNm/m

0.71

The output of the method returns the total capacity of the section. However, often a result per metre height is desired, this is provided in the text output when verbose = True