An Analytical Field and Model Study of M-Beam Bridge Decks
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DOCTOR OF PHILOSOPHY An Analytical Field and Model Study of M-beam Bridge Decks Kirkpatrick, James Award date: 1982 Awarding institution: Queen's University Belfast Link to publication Terms of use All those accessing thesis content in Queen’s University Belfast Research Portal are subject to the following terms and conditions of use • Copyright is subject to the Copyright, Designs and Patent Act 1988, or as modified by any successor legislation • Copyright and moral rights for thesis content are retained by the author and/or other copyright owners • A copy of a thesis may be downloaded for personal non-commercial research/study without the need for permission or charge • Distribution or reproduction of thesis content in any format is not permitted without the permission of the copyright holder • When citing this work, full bibliographic details should be supplied, including the author, title, awarding institution and date of thesis Take down policy A thesis can be removed from the Research Portal if there has been a breach of copyright, or a similarly robust reason. 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Oct. 2021 AN ANALYTICAL FIELD AND MODEL STUDY OF M-BEAM BRIDGE DECKS Thesis submitted to The Queen’s University of Belfast by James Kirkpatrick, B.Sc., C.Eng., M.I.Struct.E., MRAeS, MIHE for The Degree of Doctor of Philosophy in -S The Faculty of Engineering (Department of Civil Engineering) April 1982 Opinions expressed in this thesis are not necessarily those of the Department of the Environment (N.J.) Roads Service. SUMMARY An analytical field and model study of M—beam bridge decks is presented. The field study involved testing four full size bridges during construction to establish the load distribution characteristics and included both tee beam and pseudo—box types of deck. After valid ating the grillage method of analysis using the results of these tests, simplified graphical methods of predicting the design bending moments in beams were developed analytically. These are applicable to beams at spacings varying from 1.0 m to 2.0 m with the latter being consider ed for economic reasons. When these design charts are combined with a series of interactive programs for the Hewlett Packard desk top computer they provide a streamlined design procedure which reduces design time to a minimum. The strength of the standard 160 mm M—beam deck slab under the action of the abnormal vehicle wheel load was investigated in a series of tests on a - scale model. The main variables were the percentage of steel reinforcement and the spacing of the beams. Twenty panels were tested and they all failed in a punching shear mode. A detailed analysis of results has shown that the ultimate capacity of bridge slabs is greatly enhanced by compressive membrane action and the failure load is virtually independent of the percentage of transverse reinforcement. A method of predicting the ultimate capacity, in which it is assumed that bridge slabs are fully restrained laterally, is presented. This is based on a modified punching shear equation with the enhancement due to compressive membrane action being accounted for by an equivalent percentage reinforce ment parameter, the actual slab reinforcement being neglected. Excellent correlation is achieved with the model tests and with the results of relevant tests reported in the literature. 1. Finally, proposals are presented for the design of M-beam deck slabs using reduced levels of reinforcement which will provide an acceptable level of serviceability and further savings in the cost of M-beam decks over and above those achieved by increased spacing of the beams. 11. CONTENTS Page SUMMARY iv NOTATION vii LIST OF PHOTOGRAPHS Viii ACKNOWLEDGEMENTS CHAPTER ONE INTRODUCTION 1 - REVIEW 5 CHAPTER TWO BEAM AND SLAB BRIDGE DECKS A HISTORICAL 48 CHAPTER THREE FULL SCALE LOADING TESTS 66 CHAPTER FOUR PRESENTATION AND OISCUSSION OF RESULTS 97 CHAPTER FIVE OESIGN METHODS FOR M—BEAM BRIDGE DECKS 171 CHAPTER SIX STRUCTURES FOR ASSESSING THE STRENGTH OF DECK SLABS CHAPTER SEVEN DESCRIPTION OF TEST STRUCTURES AND EXPERIMENTAL PROCEDURE 194 TESTS 224 CHAPTER EIGHT PRESENTATION AND DISCUSSION OF RESULTS OF MODEL 270 CHAPTER NINE DESIGN OF RIGIDLY RESTRAINED BRIDGE SLABS 304 CHATPER TEN CONCLUSIONS AND SUGGESTIONS FOR FURTHER RESEARCH 311 APPENDIX A COMPARISON OF COSTS FOR SHORT SPAN BRIDGE DECKS 314 APPENDIX B POLYSTYRENE MODEL TESTS 319 APPENDIX C COMPUTER PROGRAMS FOR NI—BEAM BRIDGE DECKS 376 APPENDIX D CALCULATION OF PROTOTYPE SLAB REINFORCEMENT 381 APPENDIX E DESIGN OF MODEL BEAMS SLABS 387 APPENDIX F COMPRESSIVE MEMBRANE ACTION IN RESTRAINED BRIDGE BIBLIOGRAPHY 392 111. NOTATION The following notation covers the majority of symbols used in the text and any additional symbols are defined as they occur. a’ distance from the compression face to the point at which the crack width is being calculated. distance perpendicular to the reinforcement from the point consid ered to the surface of the nearest reinforcing bar. A5 area of tension reinforcement perpendicular to the crack. width of the section at the centroid of the tension steel. c column side length. c. minimum cover to tensile reinforcement. either the distance from the point at which the crack width is being considered to the surface of the nearest reinforcing bar running perpendicular to the crack or the distance from the point at which the crack width is being considered to the neutral axis whichever is the lesser. force in compression zone of slab. CL twisting inertia from longitudinal cross—section of pseudo-box deck. d effective depth of tension reinforcement. E Young’s modulus. concrete cylinder compressive strength. cu concrete cube compressive strength. concrete tensile strength. fy characteristic yield strength of reinforcement. G shear modulus of elasticity. h overall slab depth. bending inertia per unit width of deck. iv. 10 torsional inertia per unit width of deck. I bending inertia of grillage beam. j bending inertia per unit length of deck. torsional inertia per unit length of deck. U torsional inertia of grillage beam. k reduction coefficient. coefficient for beam bending moment envelope. L span. M The midspan beam bending moment in an individual deck span. MA bending moment at point A on bending moment envelope. Mar maximum arching moment for an elastic/plastic material Mar(max) maximum arching moment for a rigid/plastic material. May average niidspan bending moment of all the beams in the deck. M8 bending moment at point B on bending moment envelope. Mmax maximum M—beam bending moment due to live load Mr arching moment ratio. M(u) arching moment P point load on slab P predicted slab capacity. test load at failure. q proportioning factor for torsional inertia of pseudo—box deck. R arching parameter Rb beam reaction. u deflection parameter (a/h) Ut transfer cube strength. 28-day cube strength. vc ultimate allowable shear stress. w uniformly distributed load. (w) theoretical crack width. W equivalent wheel load on beam. v. x lateral co-ordinate in x direction. y lateral co-ordinate in y direction. distance of centroid of HB vehicle from centre line of edge beam. z displacement perpendicular to elastic plate. torsional parameter for load distribution. A deflection. e strain. sa the apparent tensile strain in the concrete at the point under consideration in a direction perpendicular to the crack. Ec plastic strain for an elastic/plastic material. the average strain, at the level where cracking is being considered, calculated allowing for the stiffening effect of the concrete in the tension zone. e1 strain ignoring tension stiffening in the equation for C o flexural parameter for load distribution. Poisson’s ratio reinforcement ratio. 2av average reinforcement ratio. equivalent reinforcement ratio. diameter of loading shoe. a stress. vi LIST OF PHOTOGRAPHS PLATE 3.1 The Bann River Bridge PLATE 3.2 The Tullyear Road Bridge PLATE 3.3 The A50 Road Bridge PLATE 3.4 Strain Gauges Being Attached to the Bann River Bridge PLATE 3.5 The Digital Portable Weighpad PLATE 3.6 Test Lorries on the ASO Road Bridge PLATE 7.1 Clinghans Bridge Site PLATE 7.2 Model Beams and Diaphragms PLATE 7.3 Typical Deck Reinforcement PLATE 7.4 Parapet Upstand Reinforcement PLATE 7.5 Completed Deck Reinforcement PLATE 7.6 Completed Deck Reinforcement with End Stops for Casting PLATE 7.7 Model Deck and Test Frame PLATE 7.8 Single Wheel Loading Shoe PLATE 7.9 Double Wheel Loading Shoe PLATE 7.10 Single Wheel Loading Shoe for Creep Test PLATE 7.11 Deflection Transducers PLATE 8.1 Typical Crack Patterns for Large Panels PLATE 8.2 Typical Crack Patterns for Small Panels PLATE 8.3 Typical Sections Through Failure Cones PLATE 8.4 Typical Sections Through Diaphragms and Slab PLATE 8.5 Soffit Failure Area and Cone 61 PLATE 8.6 Soffit Failure Area and Cone Dl PLATE 81 Polystyrene Test Model vii. ACKNOWLEDGEMENTS I would like to thank the Department of the Environment (NI) Roads Service for sponsoring this research project and in particular the Director, Mr. T.A.N. Prescott for his continual support and encouragement. I must also record my sincere thanks to Professor A.E.