Design and Analysis of a Network Arch Bridge - Instituto Superior

153 Pages·2013·6.34 MB·English

Design and Analysis of a Network Arch Bridge

Bernardo Morais da Costa

Thesis to obtain the Master of Science Degree in
Civil Engineering

Examination Committee

Chairperson: Professor José Manuel Matos Noronha da Câmara
Supervisor: Professor José Joaquim Costa Branco de Oliveira Pedro
Member of the Committee: Professor Francisco Baptista Esteves Virtuoso

October 2013

Abstract

The present dissertation aims the design and analysis of the hanger arrangement and the
structural stability of a Network arch bridge – a tied-arch bridge with inclined hangers that cross
each other at least twice. A comparative analysis with other types of hanger arrangements is also
performed.
Possible solutions with respect to spans, materials and deck cross-section typology are presented
and succinctly discussed. Modeling using a tridimensional finite element model of the main bridge
is described.
A detailed analysis of the hanger arrangement influence on the structural behavior is performed
for the adopted solution. Four different arrangements of hangers – a vertical, a Nielsen and two
different Network arrangements – are compared in terms of stress distributions, deflections,
hangers’ relaxation and fatigue behavior.
The linear stability analysis is finally performed for the four different models, comparing their
buckling modes and discussing the results with respect to different load patterns and load
increments. The critical loads are evaluated using the European standards formulation, a
simplified method and FEModel models.

Keywords: Network arch bridge, Tied-arch bridge, Bowstring bridge, roadway bridge design,
hanger arrangement, arch buckling, arch stability analysis
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Resumo

Na presente dissertação apresenta-se o projeto base de uma ponte em arco superior do tipo
Network – uma ponte do tipo Bowstring com pendurais inclinados que se cruzam entre si pelo
menos duas vezes. São também analisados e comparados outros tipos de arranjo dos pendurais.
Possíveis soluções relativamente aos vãos, aos materiais e à secção transversal do tabuleiro são
apresentadas e sucintamente discutidas. A modelação, usando um modelo de elementos finitos da
ponte, é descrita.
É analisada a influência do tipo de arranjo dos pendurais na resposta estrutural do modelo. Quatro
tipos diferentes de arranjos: um vertical, um Nielsen e dois arranjos Network diferentes são
comparados em termos das distribuições de esforços, deformações, comportamento à fadiga e
relaxação dos pendurais.
Finalmente foi realizada uma análise linear de estabilidade para os quatro modelos diferentes,
comparando os seus modos de instabilidade e discutindo os resultados para diferentes
distribuições e incrementos de carga. As cargas críticas são avaliadas adotando diferentes
procedimentos do Eurocódigo, um método simplificado e análises lineares e não lineares de um
modelo de elementos finitos.

Palavras-chave: ponte Network, ponte Bowstring, ponte em arco superior, arranjo de pendurais,
dimensionamento de ponte rodoviária, estabilidade do arco, instabilidade do arco
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Acknowledgements

I want to first express my gratitude towards Professor José Oliveira Pedro for giving me the
opportunity of studying this subject and continuously guiding me throughout the entire duration
of this dissertation, and to Professor Angel C. Aparicio Bengoechea. Only with these esteemed
professors continuous help, amazing knowledge, motivating personalities and inspiring teachings I
was able to develop the design and analysis here presented. Along with Professor Francisco
Virtuoso, the three were my personal favorite professors during my entire career, and to have two
of them actually guiding and supporting my project is a true blessing.
Acknowledgments also to Professors Joan Ramon Casas and Philippe Van Bogaert, Eng. Pedro
Gonçalves and mostly to Diogo Tomás Peixoto, for his true contribute and incentives.
The result of this dissertation was only possible thanks to Per Tveit, Benjamin Brunn, Frank
Shanack and several other researchers’ intensive work on the subject and their will to share it on
numerous publications. For that I am honestly grateful. Though, my most special thanks go to my
parents, not for the thesis, but for the person who made it, that they, kindheartedly, designed!
And I hope to show that to them, every day.
Finally, I send my appreciations to all the people who use bridges as metaphors for good things, as
they, in a certain way, contribute to a more pleasant and gratifying result from the study of this
type of structures.

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Contents

1. Introduction..................................................................................................................................... 1
1.1 General Overview ...................................................................................................................... 1
1.2 Main Objectives ......................................................................................................................... 3
1.3 Document Outline ..................................................................................................................... 4
2. Alternative and Adopted Solution ................................................................................................... 5
2.1 Local Constraints ....................................................................................................................... 5
2.2 Alternative Solutions ................................................................................................................. 6
2.2.1 Options for the Bridge Spans ............................................................................................. 6
2.2.2 Deck Cross-Section Solutions ............................................................................................. 8
2.3 Adopted Solution ...................................................................................................................... 8
2.3.1 General Layout ................................................................................................................... 8
2.3.2 Composite Deck Advantages ............................................................................................ 13
2.3.3 Structural Elements .......................................................................................................... 14
2.3.3.1 Slab ........................................................................................................................... 14
2.3.3.2. Tie (Longitudinal Beam) .......................................................................................... 15
2.3.3.3. Rib (Transversal Beam) ............................................................................................ 16
2.3.3.4. Arch ......................................................................................................................... 16
2.3.3.5. Hangers (Network Arrangement) ............................................................................ 18
2.3.3.6. Secondary Elements – (Bracing Beams and End-Cross-Girders) ............................. 24
2.3.4 Deck Support Conditions .................................................................................................. 25
2.3.5 Constructive Procedures .................................................................................................. 26
2.3.6 Comparison with Built Tied-Arch Bridges ........................................................................ 31
3. Design Actions and Modeling ........................................................................................................ 35
3.1 Actions ..................................................................................................................................... 35
3.1.1 Traffic Loads ..................................................................................................................... 35
3.1.1.1 Approach Viaduct ..................................................................................................... 36
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3.1.1.2 Bowstring Bridge ...................................................................................................... 38
3.1.2 Wind Load ........................................................................................................................ 39
3.1.3 Seismic Action .................................................................................................................. 40
3.1.4 Temperature Actions ........................................................................................................ 41
3.1.5 Combinations of Actions .................................................................................................. 42
Ultimate Limit State (ULS) .................................................................................................... 42
Serviceability Limit State (SLS) ............................................................................................. 43
3.2 Modeling ................................................................................................................................. 43
4. Structural Analysis ......................................................................................................................... 47
4.1 Overview ................................................................................................................................. 47
4.2 Deck Slab Analysis ................................................................................................................... 47
4.3 Ribs Analysis ............................................................................................................................ 54
4.4 Ties Analysis ............................................................................................................................ 58
4.5 Arches Analysis ........................................................................................................................ 69
4.6 Hangers Analysis ..................................................................................................................... 73
4.7 Expansion Joints ...................................................................................................................... 81
5. Hanger Arrangements and Arch Instability Investigations ........................................................... 85
5.1 Overview ................................................................................................................................. 85
5.2 Hanger Arrangements’ Investigations ..................................................................................... 86
5.3 Arch Instability Analysis........................................................................................................... 94
5.3.1 Load cases and sequence of application .......................................................................... 94
5.3.2 Critical loads and buckling modes .................................................................................... 96
5.3.3 Other forms of evaluating the arch critical load ............................................................ 105
5.3.4 Discussion of the results ................................................................................................. 111
6. Conclusions and Future Developments....................................................................................... 113
6.1 General Conclusions .............................................................................................................. 113
6.2 Future Developments ............................................................................................................ 114
References ....................................................................................................................................... 115
Appendixes ....................................................................................................................................... A-1
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