Structural Masonry: An Experimental/Numerical Basis for Practical Design Rules

This text provides a basis for a standardized approach to structural masonry, using an integration of experimental and computational techniques. Accurate displacement-controlled materials experiments have produced an extensive database of strength, stiffness and softening properties for tension, compression and shear, and this data has been transferred into numerical models for simulating the deformational behaviour of masonry structures. The models have been implemented into finite and distinct element codes and have subsequently been verified against shear wall experiments and analytical solutions for masonry parts.

Table of Contents:
PREFACE -- SUMMARY -- SYMBOLS -- 1 INTRODUCTION -- 1.1 General -- 1.2 Purpose and framework of the research -- 2 TESTING OF MATERIALS -- 2.1 General -- 2.2 Materials, their processing and coding -- 2.2.1 Materials -- 2.2.2 Manufacturing of specimens -- 2.2.3 Terminology -- 2.2.4 Coding -- 2.3 Mechanical properties of masonry in compression -- 2.3.1 Specimens -- 2.3.2 Testing -- 2.3.3 Progress of the test -- 2.3.4 Compressive strength -- 2.3.5 Elastic modulus -- 2.3.6 Transverse contraction -- 2.4 Tension tests -- 2.4.1 Specimen -- 2.4.2 Testing -- 2.4.3 Tensile strength of the joints and the units -- 2.4.4 Elastic moduli of the joints in tension -- 2.4.5 Fracture energy and ‘post peak’ behaviour -- 2.4.6 Influence of the real (net) bonding surface -- 2.5 Joint shear tests -- 2.5.1 Specimen -- 2.5.2 Testing -- 2.5.3 Tensile tests with shear tests -- 2.5.4 Shear strength -- 2.5.5 Shear stiffness or shear modulus of the mortar joint -- 2.5.6 Friction coefficient -- 2.5.7 Cohesion-softening and shear crack energy -- 2.5.8 Dilatancy -- 2.5.9 CEN tests 2.6 Conclusions -- 2.6.1 Conclusions with regard to the compression tests -- 2.6.2 Conclusion with regard to the tension tests -- 2.6.3 Conclusion with regard to the shear tests -- 2.6.4 General conclusions -- 3 NUMERICAL MODELS IN DIANA -- 3.1 General -- 3.2 Non-linear finite element method -- 3.2.1 Points of departure and types of elements -- 3.2.2 Solution procedure for non-linear material behaviour -- 3.3 Joint-unit discontinuum models -- 3.3.1 Points of departure -- 3.3.2 Modelling of units, joints and areas of adhesion -- 3.3.3 Linear-elastic behaviour -- 3.3.4 Discrete crack formation -- 3.3.5 Coulomb friction -- 3.3.6 Combination cracking and Coulomb friction -- 3.3.7 Alternative formulations -- 3.4 Super elements -- 3.5 Anisotropic continuum models for masonry as a composite -- 3.5.1 Points of departure -- 3.5.2 Orthotropic-elastic behaviour -- 3.5.3 Smeared cracking -- 3.5.4 Plasticity -- 3.6 Sense and nonsense with regard to the scatter in material properties -- 4 EVALUATION AND VERIFICATION STUDIES WITH DIANA -- 4.1 General -- 4.2 Verification study of piers in shear -- 4.2.1 Experimental results -- 4.2.2 Modelling -- 4.2.3 Numerical results -- 4.2.4 Evaluation of modelling aspects -- 4.2.5 Striking influence of dilatancy -- 4.2.6 Conclusions -- 4.3 Evaluation study of wall parts in tension -- 4.3.1 From micro to macro via numerical simulations -- 4.3.2 Analytical reference data -- 4.3.3 Numerical modelling -- 4.3.4 Results -- 4.3.5 Comparison with analytical formulations -- 4.3.6 Influence of dilatancy -- 4.3.7 Influence of the type of masonry (calcium silicate unit /clay unit) -- 4.3.8 Influence of dimensions of units, blocks and elements -- 4.3.9 Influence of top load -- 4.3.10 Influence of open head joints -- 4.3.11 Conclusions -- 5 NUMERICAL STUDIES WITH UDEC -- 5.1 Distinct element method -- 5.1.1 Division into blocks and interfaces -- 5.1.2 Geometrical non-linearity -- 5.1.3 Explicit dynamic solution procedure -- 5.1.4 Constitutive models -- 5.2 Evaluation study of narrow pier -- 5.2.1 Modelling -- 5.2.2 Results -- 5.3 Evaluation study of wide pier with opening -- 5.3.1 Modelling -- 5.3.2 Results -- 5.4 Comparison of distinct element method with finite element method -- 6 CASE STUDY CRACKING BEHAVIOUR OF WALLS UNDER RESTRAINED SHRINKAGE -- 6.1 Introduction -- 6.2 Definition of the problems -- 6.2.1 Behaviour of walls with obstructed shrinkage -- 6.2.2 Influencing parameters -- 6.2.3 Present-day knowledge in the analytical and experimental field -- 6.3 Numerical research -- 6.3.1 Modelling -- 6.3.2 Results -- 6.4 Influence of boundary conditions -- 6.4.1 Axial degree of restraint -- 6.4.2 Bending stiffness of the restraint -- 6.4.3 Two-sided restraint -- 6.4.4 Friction /slip and top load -- 6.5 Influence of material parameters -- 6.6 Influence of geometry: Wall length -- 6.7 Conclusion: The step to calculation rules -- 6.8 Practical relevance -- 7 CASE STUDY PIER-MAIN WALL CONNECTIONS -- 7.1 Introduction -- 7.2 Present-day knowledge in the analytical field -- 7.3 Present-day knowledge in the experimental field -- 7.4 Numerical modelling -- 7.5 Numerical results -- 7.6 Conclusion: The step to calculation rules 8 CONCLUDING REMARKS -- APPENDIX: INFLUENCE OF WALL LENGTH ON STRESS -- DISTRIBUTION WITH RESTRAINED SHRINKAGE -- REFERENCES.

About the Author :
CUR Centre for Civil Engineering Research and Codes. TNO Building and Construction Research, Rijswijk, Netherlands.