Seismic Vulnerability Assessment and Retrofitting Strategies for Masonry Infilled Frame Building (Springer Theses)

This book reports on a comprehensive experimental characterization of the material, mechanical and dynamic properties of masonry infill walls. It analyses the critical parameters affecting their out-of-plane seismic behavior, including the effects of the panel support conditions, gravity load, and previous damage. Further, it offers an extensive review of infill masonry strengthening strategies and reports on the experimental assessment of various textile-reinforced mortar (TRM) strengthening solutions. It also presents the development, implementation and calibration of a numerical model to simulate the infill panels’ seismic behavior, with the corresponding findings of various tests to assess the seismic vulnerability of an infilled RC structure. All in all, this outstanding PhD thesis offers a comprehensive review of masonry infill walls, and a timely overview of numerical and experimental methods for testing and preventing the out-of-plane seismic collapse of RC buildings. Supervisor’s Foreword Parts of this thesis have been published in the following documents Acknowledgements Contents 1 Introduction 1.1 Framework and Motivation 1.2 Objectives and Tasks 1.3 Thesis Organization References 2 Out−of−Plane Behaviour of Masonry Infill Walls Experimental Tests: A Systematic Review 2.1 Introduction 2.2 Methodology 2.3 Selection Criteria 2.4 Study Selection 2.5 Data Extraction, Quality Assessment and Data Synthesis 2.6 Final Database 2.7 Global Overview of OOP Tests on Infill Masonry Walls 2.8 OOP Load Application Strategies and Protocol 2.9 OOP Behaviour of As-Built Infill Masonry Walls 2.9.1 Effect of RC Frame Type and Detailing 2.9.2 Effect of Geometric Dimensions and Mechanical Properties 2.9.3 Effect of Gravity Load 2.9.4 Effect of Openings and Panel Support Conditions 2.10 Assessment of the Previous IP Damage Effect on the Infill Walls OOP Capacity 2.10.1 Background 2.10.2 Cracking Strength and Secant Cracking Stiffness 2.10.3 Maximum Strength and Secant Stiffness 2.10.4 IP−OOP Ultimate Displacement 2.11 Final Considerations References 3 Strengthening Strategies to Improve the Seismic Behaviour of Infill Masonry Walls 3.1 Introduction 3.2 Literature Review of Retrofit and Strengthening Techniques 3.2.1 Disconnection of the Infills from the Structural System 3.2.2 Infill Masonry Walls Retrofitting and Strengthening Techniques 3.2.3 Reinforced Plaster 3.2.4 Bed Joints Reinforcement 3.3 Final Considerations References 4 Experimental Characterization of the As-Built Masonry Infill Components’ Properties 4.1 Framework 4.2 Stage 1—Material Characterization Tests of Masonry Units and Mortar 4.2.1 Introduction 4.2.2 Compression Strength Tests of Masonry Units 4.2.3 Compression and Flexural Strength Tests of the Mortar 4.3 Stage 2—Mechanical Characterization of the Infill Masonry Wallets 4.3.1 Testing Campaign Overview 4.3.2 Mechanical Properties of Mortar 4.3.3 Compressive Strength Tests 4.3.4 Diagonal Tensile Strength Tests 4.3.5 Flexural Strength Tests 4.3.6 Final Remarks on Stage 2 Tests 4.4 Stage 3—Dynamic Characterization of Infill Panels Through Ambient Vibration Tests 4.4.1 Introduction 4.4.2 Methodology 4.4.3 Laboratory Tests 4.4.4 In-Situ Tests 4.4.5 Final Remarks on Stage 3 Tests 4.5 Final Considerations References 5 Experimental Evaluation of the Out-of-Plane Behaviour of As-Built Masonry Infill Walls 5.1 Introduction 5.2 Specimens Details 5.3 Material Properties and Specimen Construction 5.3.1 Concrete and Reinforcement Steel Bars 5.3.2 Mortar and Masonry Units 5.4 Stage 1—Out-of-Plane Tests Using Airbags 5.4.1 Test Setup 5.4.2 Instrumentation and Loading Protocol 5.4.3 Stage 1: Individual Test Results 5.4.4 Stage 1: Global Results’ Comparison 5.5 Stage 2—Out-of-Plane Tests Using Pneumatic Actuators 5.5.1 Test Setup 5.5.2 Instrumentation and Loading Protocol 5.5.3 Stage 2: Individual Test Results 5.5.4 Stage 2: Global Results Comparison 5.6 Overview of the Summary of Global Results: Critical Analysis 5.6.1 Effect of Columns Axial Load 5.6.2 Effect of Reduction of the Panel Support Width 5.6.3 Effect of Previous Damage 5.6.4 Effect of Plaster 5.6.5 Effect of Workmanship 5.6.6 Effect of Test Setup 5.7 Final Remarks and Major Observations from the Experimental Campaign References 6 Experimental Assessment of Strengthening Solutions to Prevent the OOP Collapse of Infill Masonry Walls Through Textile Reinforced Mortars 6.1 Introduction 6.2 Flexural Strength Tests in Strengthened Infill Masonry Wallets 6.2.1 Objectives and Specimens’ Description 6.2.2 Specimens Description and Strengthening Process 6.2.3 Test Setup Description and Instrumentation 6.2.4 Experimental Results 6.3 Experimental Assessment of TRM Solutions to Improve the Out-of-Plane Capacity of Full-Scale Infill Masonry Walls 6.3.1 Objectives and Specimens’ Description 6.3.2 Description of the Strengthening Strategies 6.3.3 Material Properties 6.3.4 Test Setup, Instrumentation and Loading Protocol 6.3.5 Experimental Results 6.3.6 Comparison of the Results and Discussion 6.4 Final Considerations References 7 Simplified Macro-modelling of Infill Masonry Walls Seismic Behaviour 7.1 Introduction 7.2 Brief Overview on Numerical Modelling Approaches: From Simplified Macro-models to Detailed Modelling 7.2.1 Simplified Macro-models 7.2.2 Detailed Micro-modelling Approach 7.3 Development of a Simplified Modelling Approach to Simulate Infill Walls in OpenSees 7.3.1 General Considerations 7.3.2 Modelling of the IP Behaviour 7.3.3 Modelling of the OOP Behaviour 7.4 Numerical Modelling Calibration 7.4.1 In-Plane Behaviour—Panels Without Openings 7.4.2 In-Plane Behaviour—Panels with Openings 7.4.3 OOP Behaviour 7.5 Case Study 7.5.1 Description of the Building 7.5.2 Numerical Modelling Strategy 7.5.3 Material Modelling Properties 7.5.4 Preliminary Results, Natural Frequencies and Vibration Modes 7.5.5 Effect of the Infill Walls in the Seismic Vulnerability Assessment of Rc Buildings Parametric Study 1 7.5.6 Effect of the Infill Panels in the Floor Response Spectra Parametric Study 2 7.5.7 Seismic Vulnerability Assessment of Infilled RC Structures Subjected to Mainshock-Aftershock Sequence Parametric Study 3 7.6 Final Considerations References 8 Final Conclusions and Future Works 8.1 Conclusions and Major Contributions 8.2 Future Works Author Biography Bibliography