[Are recent changes to the UK National Annex for Eurocode 2 for punching shear design justified and what is the effect on UK plc?]

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Acknowledgement

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.

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I [type your full first names and surname here], declare that the contents of this dissertation represent my own unaided work, and that the dissertation has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

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Abstract

With the increasing popularity of multi-storey buildings, foundation engineering is becoming a more important issue in the construction industry. In UK, sound rock can normally be found at shallow depths. However, the design codes in use locally suggest a generic design process for foundations which does not take into account the type of substrate. The focus is on critical failure modes affecting reinforced concrete pad foundations on soils. The controlling parameter in the design of these foundations is found to be punching shear. The physical properties of sound rock under load suggest that a pad foundation on rock will exhibit a different behaviour than that predicted by codes. Modern design of reinforced concrete structural members for shear is based on the theory of plasticity. This paper is written to contribute to the understanding of the inclination of the concrete strut in the inclined strut model for design of shear reinforcement in beams, which among others are used in Eurocode 2. The problem of inclination of the compression strut in truss model is analysed depending on shear reinforcement ratio and effectiveness ratio of concrete strength for compression. Also the understanding of necessary ductility in steel reinforcing bars is discussed in the paper and especially the needs of tests on translation capacity of the shear failure are here analysed. To explain these problems the paper gives a short introduction to the theory of plasticity of reinforced concrete in shear and the background for the equations, which are used in shear design according to Eurocode 2.

Table of Contents

CHAPTER 1: INTRODUCTION7

Background8

Aims8

CHAPTER 2: LITERATURE REVIEW10

Theoretical framework10

CHAPTER 3: METHODOLOGY19

Brittle rib shearing failure observed in push-out and edge-beam tests20

Push-Out Tests on a Re-Entrant Profile21

Push-Out Test on a Trapezoidal Profile23

Short-Span Edge Beam Detailed In Accordance With Bs 5950: Part 3.1 and Eurocode 2: Part 1.124

Development of a reinforcing component to prevent rib shearing failure25

Evolution of the Reinforcing Component25

CHAPTER 4: DISCUSSION AND ANALYSIS29

Shear crack width design32

Some aspects in the practical design34

Push-Out Test on a Trapezoidal Profile (Reinforcing Component Included)35

Short-Span Edge Beams (Reinforcing Component Included)36

Long-Span Edge Beam (Reinforcing Component Included)37

Design rules in AS 2327.1-1996 for preventing rib shearing failure in composite edge beams39

Composite Internal Beams41

Negative Moment Regions of Continuous Composite Beams42

Simply Supported Composite Beams with Large Steel Web Penetrations42

CHAPTER 5: CONCLUSION44

REFERENCES46

Chapter 1: Introduction

Since last century, punching has been an important problem to researchers who tried to fully understand it. No matter how many experiments were made, some models and analysis relied ...