Repair of Arch Bridges

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UNIVERSITY

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MINHO

Daniel Oliveira & Paulo Loureno

U N I V E R S I T Y O F M I N H O

Barcelona, November 17-19 2004

REPAIR OF STONE MASONRY

ARCH BRIDGES

4TH. CONFERENCE ON ARCH BRIDGES

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4 T H. C O N F E R E N C E O N A R C H B R I D G E S - B A R C E L O N A , 2 0 0 4

INTRODUCTION

INTRODUCTION

Masonry Arch Bridges in Portugal:

- Roman Period, Medieval Age and Modern Period

(Priceless architectural and cultural legacy, but often showing

signs of damage)

Major Causes of Damage:

-

Deep change of loads for which bridges were built- Lack of adequate maintenance

-Ageing processes (decay of the materials)

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INTRODUCTION

Generalized Damage:

-Absence of mortar in the stone joints

-Existence of vegetation and biological colonization

- Presence of humidity and efflorescences

-Accelerated decay of the materials

Localized Damage:- Longitudinal cracking of the arches

- Movement of abutments

- Lack of plumbness of the spandrel walls


But damage can be minimized

- By performing periodical inspections

- By reducing the traffic load

- By carrying out repair and strengthening measures

(Preventive maintenance)

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INTRODUCTION

Principles of Intervention in the Architectural Heritage(ICOMOS):

- Minimum repair to assure safety and durability

-Respect of the original conception

- Compatibility between existing and new materials


-

Survey and Repair of 2 Portuguese Masonry ArchBridges

- Boutaca Bridge

-Donim Bridge

When dealing with architectural valuable constructions

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INTRODUCTION

BOUTACA BRIDGE (stone masonry)

-Local: Batalha, center of Portugal

BOUTACABRIDGE

- Dimensions: 60m length, 7m width (5m span )

- Purpose: roadway (belonging to the former road Lisbon-Porto)

- Date of construction: 1860

T1

C6

T2

A7

C5

T3C4

T4

C3 C2

T5

C1

P7 P6

A6 A5

T6

P5 P4

A4

P3 P2

A3 A2 A1

P1

Pointed Arches

Flat roadwayTie rods + anchorages

Buttressing System

Uncertain safety conditions Survey requested4


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Results of the Survey carried out:

-Vegetation & lost of plaster (lack of maintenance)

- Humidity & biological colonization (deficient drainage system)

- Cracking in the buttress walls

-Existing anchorages much deterioratedand rather deformed (outward movement ofmasonry)

(Buttresses

overloaded)

INTRODUCTION

BOUTACABRIDGE

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Recommended Remedial Measures:

- Lightening the buttresses Tie rods + patress platesINTRODUCTION

BOUTACABRIDGE

Detail

P7

A7

C6C5

C4 C3 C2 C1

A) Structural Strengthening

Additional buttressing system

Patress plate

Tie rod6


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Waterproofing of the pavement and reconstruction of thedrainage system

INTRODUCTION

BOUTACABRIDGE

B) Other measures:

- Cleaning and removal of vegetation

- Replacement of plaster

-Need for periodical visual inspections

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DONIM BRIDGE (stone masonry)

- Local: Guimares, North of Portugal

- Dimensions: 62m length, 4m width (larger span 12m)

- Purpose: roadway (major importance untill 2 centuries ago)

- Date of construction: 15th 16th centuryINTRODUCTIONBOUTACABRIDGE

DONIM BRIDGE

A1 A2 A3 A4

Left pier

Right pier

Semicircular Arches

Flat roadway

Pier + Cutwaters

Flood arch

Precarious safety conditions Survey requested8


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Results of the Survey carried out:

- Extensive longitudinal cracking in the left arch

- Infesting vegetation all over the bridgeINTRODUCTION

BOUTACABRIDGE

DONIM BRIDGE

- Longitudinal cracking in the flood (right) arch

- Cutwater of the right pier highly damaged

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- 1 block foundation missing (underwater inspection)

INTRODUCTION

BOUTACABRIDGE

DONIM BRIDGE

-A numerical analysis (3D, non-linear) carried out allow toconfirm the damage observed and helped understandingits causes

- Spandrel walls out of plumb

(Incremental principal strains)

Major problems :

- Outward movements of spandrel walls

- Longitudinal cracking in the left and right arches

- Pre-collapse of a cutwater (right pier) 10


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INTRODUCTION

BOUTACABRIDGE

DONIM BRIDGE

Recommended Remedial Measures:

-Remove of the infill

A) Left Arch (return joints thickness to its original width)

Tie-rod

U profilesAnchor rods

ARCH

SPANDRELWALL

-Voussoirs placed in their original positions by means ofrope-strechers

- Fastening of stainless steel U profiles placed in a U shape

above the arch and close to the spandrel walls- Tie rod to bind the spandrel walls

- Infill put back into its place

] profiles

shape

tie rod

Anchorrods

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INTRODUCTION

BOUTACABRIDGE

DONIM BRIDGE

-Full width anchors across the arch

B) Flood (right) Arch (prevent further spreading of the arch)

- Stitching anchors linking the arch to the spandrel walls

Stitchinganchors

Full widthanchors

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INTRODUCTION

BOUTACABRIDGE

DONIM BRIDGE

-

Dismantling and rebuilding of the right cutwater (samestones + steel cramps + steel latches)

C) Other measures:

- Replacement of the missing foundation stone block

- Waterproofing of the pavement and reconstruction of the

drainage system- Cleaning and removal of vegetation

- Repointing of the deteriorated masonry joints

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Final Remarks

- Cleaning and removal of vegetation

INTRODUCTION

BOUTACABRIDGE

DONIM BRIDGE

FINAL REMARKS

-Adoption of repair measures compatible with modernprinciples of structural intervention in the architecturalheritage

-Waterproofing and drainage of the pavement

Common features to both examples

Thank you for your attention

www.civil.uminho.pt/masonry

Documents

Repair of Arch Bridges