Analysis of Tri-axial Stress-strain Conditions of Pre-stressed Masonry Corner

Analysis of Tri-axial Stress-strain Conditions

of Pre-stressed Masonry Corner

VSB-TU, Faculty of Civil Engineering

Radim Cajka

Pavlina Mateckova

Lucie Mynarzova

Marie Stara

Ostrava, Czech Republic

REC 2012, Brno, Czech Republic, 13.-15. June, 2012

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PRE-STRESSED MASONRYMotivation for testing


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PRE-STRESSED MASONRY

Description of testing

5REC 2012, Brno, Czech Republic, 13.-15. June, 2012

Masonry corner

• Plan dimensions 900 x 900 mm

• Thickness of the wall 450 mm

• Height 900 mm




Material

• Clay bricks

• Lime-cement mortar




Vertical load and pre-stressing force• 0.125 MPa 50 kN100 kN• 0.250 MPa 50 kN100 kN




Measuring of deformations

• Net of potentiometer sensors

• Short time deformations

• Pre-stressing in one or two directions


Material characteristics


Bricks from demolished building

• HistAn software

• 6 bricks

• From each 4 specimen

• Mean value fb = 16.08 MPa

• Variation coefficient 0.28


Material characteristics

10REC 2012, Brno, Czech Republic, 13.-15.June, 2012

Mortar from dry mixture

• HistAn software

• 6 block specimen

• Mean value fm = 9.8 MPa

• Variation coefficient 0.04


Masonry compressive strength


AntHill software using monte carlo simulation




AntHill software using monte carlo simulation

•fmean = 7.37 MPa

•fk = 5.29 MPa




Action effect from pre-stressingPre-stressing force

Anchoring plate

Stress in anchoring area

Ratio to vertical strength

kN m MPa %50 0.3 x 0.3 0.556 11100 0.3 x 0.3 1.111 2150 0.2 x 0.2 1.250 24100 0.2 x 0.2 2.500 4750 0.15 x 0.15 2.222 42100 0.15 x 0.15 4.444 84

TESTING RESULTS

Direction of pre-stressing


TESTING RESULTS

Net of measuring poitns


TESTING RESULTS

Measured deformations


Vertical load 0.125 MPa, pre-stressing force 100 kN

TESTING RESULTS

Measured deformations


Vertical load 0.125 MPa, pre-stressing force 100 kN

MASONRY NUMERICAL MODELLING

Basic ways of modelling


Complicated with following factors:

•Different material properties of basic components

•Different dimensions of basic components

•Narrow dimension of mortar joint

•Geometrical arrangement of bricks

•Different structural response for different load action direction

•Interaction between components

•Quality of manufacturing

•Environmental influence


Basic ways of modelling


Three basic approaches:

•Detailed micromodel

•Simplified micromodel

•Macromodel


Micromodel


Ansys software:

•Solid 45

•Link 8


From micromodel to macromodel



From micromodel to macromodel


Input and output parameters

MaterialModulus

of Elasticity [GPa]

Shear modulus [GPa]

Poissons’ ratio [-]

Input

Bricks 290/140/65

15,00 0,15

Mortar 10MPa

10,00 0,2

Output

Masonry x direction

13,96 3,65 0,202

Masonry y direction

14,00 5,56 0,198

Masonry z direction

13,84 4,30 0,197


Macromodel


Ansys software:

•Solid 45

•Link 8


Micromodel x Macromodel


Section in place of upper pre-stressing bar

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• Testing of masonry corner exposed to tri-axial loadSmall measured deformations Unexpected course of deformation

•Testing of material propertiesRelatively high strength of bricksHigh variation coefficient

• Numerical modelling of masonryCalculated deformation respond to measurementsMicromodel reflect the expeceted way of str. break

CONCLUSION


Thanks for attention!

VŠB-TU, Faculty of Civil Engineering

Ostrava, Czech Republic


Analysis of Tri-axial Stress-strain Conditions of Pre-stressed Masonry Corner

Documents

czech republicrec

prestressed masonrymotivation

prestressing force0

vertical load

vertical strengthknmmpap0

mpavariation coefficient

anthill software

masonry corner plan