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4TH. CONFERENCE ON ARCH BRIDGES. Barcelona, November 17-19 2004. REPAIR OF STONE MASONRY ARCH BRIDGES. Daniel Oliveira & Paulo Lourenço U N I V E R S I T Y O F M I N H O. . . Masonry Arch Bridges in Portugal:. Major Causes of Damage:. -. -. -. -.
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4TH. CONFERENCE ON ARCH BRIDGES Barcelona, November 17-19 2004 REPAIR OF STONE MASONRY ARCH BRIDGES Daniel Oliveira & Paulo Lourenço U N I V E R S I T Y O F M I N H O
Masonry Arch Bridges in Portugal: Major Causes of Damage: - - - - Roman Period, Medieval Age and Modern Period (Priceless architectural and cultural legacy, but often showing signs of damage) Deep change of loads for which bridges were built Lack of adequate maintenance Ageing processes (decay of the materials) 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
Generalized Damage: Localized Damage: - - - - - - - - - - Presence of humidity and efflorescences By performing periodical inspections Absence of mortar in the stone joints Lack of plumbness of the spandrel walls Movement of abutments Existence of vegetation and biological colonization By carrying out repair and strengthening measures… By reducing the traffic load Accelerated decay of the materials Longitudinal cracking of the arches But damage can be “minimized”… 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 (Preventive maintenance)
Principles of Intervention in the Architectural Heritage (ICOMOS): Survey and Repair of 2 Portuguese Masonry ArchBridges - - - - - - … Compatibility between existing and new materials Boutaca Bridge Respect of the original conception Minimum repair to assure safety and durability Donim Bridge 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 When dealing with architectural valuable constructions… INTRODUCTION
BOUTACA BRIDGE (stone masonry) - - - - Date of construction: 1860 Purpose: roadway (belonging to the former road Lisbon-Porto) Dimensions: 60m length, 7m width (5m span ) Local: Batalha, center of Portugal Tie rods + anchorages Flat roadway Pointed Arches Buttressing System Uncertain safety conditions Survey requested 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 BOUTACA BRIDGE
Results of the Survey carried out: - - - Vegetation & lost of plaster (lack of maintenance) Humidity & biological colonization (deficient drainage system) Cracking in the buttress walls 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 BOUTACA BRIDGE (Buttresses overloaded) - Existing anchorages much deteriorated and rather deformed (outward movement of masonry)
Recommended Remedial Measures: - Lightening the buttresses Tie rods + patress plates 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 A) Structural Strengthening INTRODUCTION Additional “buttressing system” BOUTACA BRIDGE Patress plate Tie rod
- - - - Waterproofing of the pavement and reconstruction of the drainage system Cleaning and removal of vegetation Replacement of plaster Need for periodical visual inspections 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 B) Other measures: INTRODUCTION BOUTACA BRIDGE
DONIM BRIDGE (stone masonry) - - - Local: Guimarães, North of Portugal Purpose: roadway (major importance untill 2 centuries ago) Date of construction: 15th – 16th century Flat roadway Flood arch Semicircular Arches Pier + Cutwaters Precarious safety conditions Survey requested 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 - BOUTACA BRIDGE Dimensions: 62m length, 4m width (larger span ≈ 12m) DONIM BRIDGE
Results of the Survey carried out: - - - - Extensive longitudinal cracking in the left arch Infesting vegetation all over the bridge Longitudinal cracking in the flood (right) arch Cutwater of the right pier highly damaged 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 BOUTACA BRIDGE DONIM BRIDGE
Major problems : - - - - - - 1 block foundation missing (underwater inspection) A numerical analysis (3D, non-linear) carried out allow to confirm the damage observed and helped understanding its causes Pre-collapse of a cutwater (right pier) Longitudinal cracking in the left and right arches Spandrel walls out of plumb Outward movements of spandrel walls 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 BOUTACA BRIDGE DONIM BRIDGE (Incremental principal strains)
Recommended Remedial Measures: - - - - - Voussoirs placed in their original positions by means of rope-strechers Fastening of stainless steel U profiles placed in a U shape above the arch and close to the spandrel walls Remove of the infill Tie rod to bind the spandrel walls Infill put back into its place 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 A) Left Arch (return joint’s thickness to its original width) INTRODUCTION BOUTACA BRIDGE DONIM BRIDGE tie rod ] profiles U shape Anchor rods
- - Full width anchors across the arch Stitching anchors linking the arch to the spandrel walls Stitching anchors Full width anchors 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 B) Flood (right) Arch (prevent further spreading of the arch) INTRODUCTION BOUTACA BRIDGE DONIM BRIDGE
- - - - - Dismantling and rebuilding of the right cutwater (same stones + steel cramps + steel latches) 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 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 C) Other measures: INTRODUCTION BOUTACA BRIDGE DONIM BRIDGE
Final Remarks - - - Cleaning and removal of vegetation Adoption of repair measures compatible with modern principles of structural intervention in the architectural heritage Waterproofing and drainage of the pavement Thank you for your attention www.civil.uminho.pt/masonry 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 Common features to both examples INTRODUCTION BOUTACA BRIDGE DONIM BRIDGE FINAL REMARKS