Design of a single track railway network arch bridge

90 Pages·2011·2.54 MB·English

by  Maxime Varennes

i
Design of a single-track
railway network arch bridge
According to the Eurocodes

MAXIME VARENNES

Master of Science Thesis
Stockholm, Sweden 2011

Design of a single-track
railway network arch bridge
According to the Eurocodes
Maxime Varennes
TRITA-BKN.Master Thesis 325
Structural Design and Bridges, 2011
ISSN 1103-4297
ISRN KTH/BKN/EX-325-SE
©Maxime VARENNES, 2011
Royal Institute of Technology (KTH)
Department of Civil and Architectural Engineering
Division of Structural Design and Bridges
Stockholm, Sweden, 2011
Preface
This Master’s thesis was carried out at the division of Structural Design and Bridges at
the Royal Institute of Technology (KTH) at Stockholm, Sweden. The work was
conducted under the supervision of Prof. Håkan Sundquist whom I want to thank for
his advice, guidance, and especially for the trust and freedom he gave me by allowing
me to do what I wanted most. I want to thank Prof. Raid Karoumi for giving me the
subject of my thesis and showing me first what a network arch bridge was. Many
people helped me conduct the thesis: John Leander, Ph.D student for Abaqus, but
mostly my friends and fellow students from the department for their advice and
constant availability.
I also wish to thank everyone that supported me during these six months in Sweden, in
France or even from abroad.
Stockholm, August 2011

Maxime Varennes

i

Abstract
A constant research of more ecological and efficient structures has enabled bridges to
be more innovative through the years. Nowadays, as the need is greater than ever, a
new kind of bridge is expanding in the entire world: the network arch bridges. The
concept was developed by professor and engineer Per Tveit in 1955 and has been
improved since then. But it is only for 10 years that many bridges of this sort have
been built.
The aim of the thesis is to investigate the structural behavior of these bridges and their
efficiency comparing to traditional bridges. It is also proving the efficiency of the
network arches used for rail traffic. To do so, a single-track railway network arch has
been designed according to the Eurocodes. A 2D model has been designed to be
optimal and tested under Abaqus for the loads defined in the Eurocodes. Guidelines
from the literature and Per Tveit’s work have been used to determine the optimal
geometry of the bridge.
The steel weight needed for the 75 meters long bridge is assessed from the final design
and is the main parameter to compare and evaluate the network arch structural
efficiency. These results are compared with Tveit’s statements and with other
structures.

Keywords: network arch bridge, design, railway bridge, Per Tveit, finite element
analysis, tied-arch, comparison.

iii

Contents
Preface ..................................................................................................................... i
Abstract ................................................................................................................. iii
1 Introduction ................................................................................................... 1
1.1 What is a network arch? .............................................................................. 1
1.1.1 The arch: ......................................................................................... 1
1.1.2 The hangers ..................................................................................... 2
1.1.3 The lower chord ............................................................................... 3
1.1.4 Common misunderstanding ............................................................. 4
1.2 Why a network arch? .................................................................................. 5
1.2.1 Structural ........................................................................................ 5
1.2.2 Environmental ................................................................................. 6
1.2.3 Practical ........................................................................................ 11
1.2.4 Economical .................................................................................... 12
1.3 The development of the network arch ........................................................ 13
1.4 Aim and scope ........................................................................................... 14
1.4.1 Aim ............................................................................................... 14
1.4.2 Scope ............................................................................................. 15
2 Preliminary design ......................................................................................... 17
2.1 Assumptions .............................................................................................. 17
2.1.1 Requirements ................................................................................ 17
2.1.2 Codes and guidelines...................................................................... 17
2.1.3 Calculations ................................................................................... 18
2.1.4 Actions and material ..................................................................... 18
2.2 Geometry .................................................................................................. 23
2.2.1 Arch rise ........................................................................................ 23
2.2.2 Hanger arrangement ...................................................................... 23
v
2.2.3 Deck cross section .......................................................................... 25
2.3 Deck .......................................................................................................... 26
2.3.1 Longitudinal direction ................................................................... 26
2.3.2 Transverse direction ...................................................................... 27
2.3.3 Reinforcement ............................................................................... 27
2.4 Arch .......................................................................................................... 28
2.5 Hangers ..................................................................................................... 30
3 Finite element model ..................................................................................... 31
3.1 Establishment of a model .......................................................................... 31
3.1.1 Choice of parameters ..................................................................... 31
3.1.2 Check of the model ........................................................................ 34
3.2 The wind portal frame ............................................................................... 37
3.3 Check of the design ................................................................................... 40
3.3.1 Influence lines ................................................................................ 40
3.3.2 At SLS ........................................................................................... 44
3.3.3 At ULS .......................................................................................... 48
4 Final design ................................................................................................... 51
4.1 Final design ............................................................................................... 51
4.1.1 Arch .............................................................................................. 51
4.1.2 Hangers ......................................................................................... 51
4.1.3 Deck .............................................................................................. 52
4.2 Steel weight assessment ............................................................................. 53
4.3 Conclusion................................................................................................. 54
4.3.1 The design ..................................................................................... 54
4.3.2 The steel saving ............................................................................. 54
4.3.3 Limits of the thesis ........................................................................ 58
4.4 Future work .............................................................................................. 59
Bibliography ........................................................................................................... 61
A Geometry of the bridge .................................................................................. 63
A.1 Initial geometry with wind portals ............................................................. 63
A.2 Final geometry (with maverick) ................................................................ 64
B Example of calculations: preliminary design of longitudinal prestress ............... 67
C Check with Vienna 200A ................................................................................ 77
v i