This thesis presents study of punching shear capacity of flat slab-column junctions. A three dimensional nonlinear finite element program based on 8 node solid elements was used to carry out the nonlinear analysis of flat-slab models with and without gabion-mesh. The effect of gabion arrangements for punching and the ultimate load prediction for each was presented in this thesis. The results obtained from abaqus were compared to code prediction results, and the failure mode also compared to experimental and code predicted failure modes. The predicted mode of failure and other responses are in a good correlation to euro code predicted values. In addition to punching gabion has greater resistance to flexure by increasing the stiffness of the slab. Finally it is concluded that using hexagonal gabion mesh at tension part is easy, effective and can solve construction difficulty of drop panels and one layer gabion can reduce 10mm of slab thickness. Punching strength is a critical point in the design of flat slabs and due to the lack of a theoretical method capable of explaining this phenomenon, empirical formulations presented by codes of practice are still the most used method to check the punching resistance of slab-column connections.
Flat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams. This type of slab is appropriate for most floor situations and also for irregular column layouts. Because of its aesthetic view, simplicity for construction, reduction of foundation cost, this becomes very common and competitive structural system for cast-in-place slabs in buildings. Flat plates allow easy and flexible partitioning of space and reduce the overall height of tall buildings. But since the load is directly transferred from slab to column due to high localized force at the column punching effect or punching shear failure is critical. This type of failure is catastrophic because no visible signs are shown prior to failure.
To increase the punching resistance of the flat slab several methods have been used, such as drop panel, column capital, column head and shear reinforcements such as shear stud and stirrups. In our country Ethiopia the first three mechanisms are used to increase the resistance of punching shear in flat slabs but shear reinforcements are being used in other countries such as America and British.
Inhaltsverzeichnis (Table of Contents)
- Chapter-1:-Introduction
- 1.1. The background
- 1.2. Statement of the problem
- 1.3. Objective of the study
- 1.4. Scope of the study
- Chapter-2:-LITERATURE REVIEW
- 2.1. Introduction
- 2.2. Behavior of slabs falling by punching
- 2.3. Enhancing the punching shear strength of flat slabs
- Chapter-3:- FINITE ELEMENT MODELING AND METHODS
- 3.1. Overview of abaqus
- 3.2. Material modeling
- 3.3. Selected geometry and modeling of flat slab
- 3.4. Material properties
- 3.5. Interaction
- 3.6. Element type selection
- 3.7. Loading and boundary condition
- 3.8. Mesh convergence
- Chapter 4:- RESULTS AND DISCUSSIONS
- 4.1. Introduction
- 4.2. Ultimate load capacity
- 4.3. Effect of gabion arrangements and their ultimate load prediction
- 4.4. Load-deflection relationships
- 4.5. Failure mode and failure location
- 4.6 Effect of gabion for flexural resistance
- 4.7 Effect of column size on percentage enhancement of gabion for punching
- 4.8 Effect of thickness of slab on punching resistance
- 4.9 Effect of drop panel for punching resistance
- 4.10 Comparison of Numerical Results with euro Code Provision
- Chapter:-5-Conclusion and recommendation
- 5.1. Conclusion
- 5.2. Recommendations
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This thesis aims to investigate the enhancement of flat slabs' punching shear resistance using gabion mesh. The study utilizes finite element modeling to evaluate the effectiveness of gabion mesh in improving the load-carrying capacity of flat slabs under punching shear stress. The analysis focuses on determining the optimal arrangement and configuration of gabion mesh for maximum shear strength enhancement.
- Punching shear resistance of flat slabs
- Finite element modeling of flat slabs with gabion mesh
- Optimal arrangement and configuration of gabion mesh
- Load-carrying capacity enhancement of flat slabs
- Failure modes and failure location under punching shear
Zusammenfassung der Kapitel (Chapter Summaries)
- Chapter 1 provides an introduction to the research, outlining the background, statement of the problem, objectives, and scope of the study. It emphasizes the importance of enhancing punching shear resistance in flat slabs, particularly in the context of modern construction.
- Chapter 2 delves into a comprehensive literature review, discussing the behavior of slabs under punching shear, existing methods for enhancing punching shear strength, and previous research on the application of gabion mesh in concrete structures. It examines the advantages and limitations of various approaches, setting the stage for the current study.
- Chapter 3 describes the finite element modeling methodology employed in the research. It introduces the software used (Abaqus) and outlines the material modeling, geometry selection, material properties, and interaction definitions for both the flat slab and the gabion mesh. It also discusses element type selection, loading and boundary conditions, and mesh convergence strategies.
- Chapter 4 presents the results and discussions of the numerical analysis. It analyzes the ultimate load capacity of the flat slab with and without gabion mesh, examines the effect of different gabion arrangements on load prediction, and investigates load-deflection relationships. It also explores the failure mode and failure location, analyzes the effect of gabion mesh on flexural resistance, and examines the influence of column size, slab thickness, and drop panels on punching resistance. Finally, the chapter compares the numerical findings with Eurocode provisions.
Schlüsselwörter (Keywords)
The primary focus of this thesis is on the enhancement of punching shear resistance in flat slabs using gabion mesh. This involves the use of finite element modeling to investigate the effectiveness of gabion mesh in increasing the load-carrying capacity of flat slabs. The research examines various factors including optimal arrangement of gabion mesh, load-deflection relationships, failure modes, and comparison with Eurocode provisions.
- Citation du texte
- Hailemelekot Haileslassie (Auteur), 2018, Enhancement of flat flabs' shear resistance using gabion mesh, Munich, GRIN Verlag, https://www.grin.com/document/937892
