BOF1: November 2000

British Waterways

Masonry Arch : TRL LINK Project DPU9/64/80

This work is part of a LINK project funded by the DETR and Industrial Partners researching the effectiveness of retrofitted reinforcement in strengthening masonry arch bridges suffering from ring separation.

The two year testing programme has recently been completed with the production of the final project report. It has been demonstrated that retrofitted reinforcement strengthening can restore the ultimate capacity of ring separated masonry arches to a level which can exceed the ultimate capacity of an equivalent "defect free" masonry arch with a barrel condition factor of unity.

However several points of interest, particularly to bridge owners, have been raised which relate to the following topics:

• Effectiveness of assessment methods
• Condition factor for ring separation
• Value of testing on "immovable" foundations
• Comparison of results of similar research undertaken by other organisations.

These will form the basis for discussion by bridge owners and to determine if further research in these areas should be undertaken.

Masonry Arch : Cardiff University EPSRC GR/L63310

In July 1997 the Engineering and Physical Research Council made a grant of approx. £200,000 to Cardiff University to study the parameters which influence the strength of masonry arch bridges.

The testing phase is now complete with a total of 30 No. 1/12^th Scale model masonry arch bridges have been loaded within a centrifuge machine.

Parameters modelled include the following:

• Equivalent 4.0m and 6.0m spans with span to rise ratio of 4 and 2 respectively.
• Different fill types limestone/clay/sand
• 3 and 2 No. brick rings
• Fill to depth ratio of 1.0 and 3.0
• Weak and strong bricks
• Loss of mortar
• Ring separation strengthened by dowel stitching and by retrofitted longitudinal reinforcement
• Concrete saddle

Such a large number of tests has generated a vast amount of comprehensive test data which will be subject to an extensive in-depth analysis over the next 12 months.

However, Cardiff University have put all the test data on the internet web site http://www.cf.ac.uk/engin/research/concmas/pb2_1.html and this can be reviewed at your own convenience.

Movable Bridges: Bristol University

British Waterways are one of the many industrial organisations providing both financial and staff resources in assisting Mr Stephen Bright in undertaking a PhD research project into movable bridges.

Stephen has completed the first year and generated a comprehensive desk study into moving bridges on a world wide basis which has produced an impressive bibliography of reference books and professional papers. His database comprises all movable bridge owners throughout the UK including number and type of movable bridge, with principle dimensions and materials.

From his background researches the University has agreed his thesis should concentrate on the optimisation of the next generation of orthotropic bridge decks.

Afternoon Discussion Topics

• Masonry Arch Bridges
  • Comparison of disparate research over last 5 years
  • Validation of assessment methods
  • Standard for design and assessment
• Movable bridges
  • Standard for design and assessment
• Bridge Management Framework
  • BRIMEwork packages, including:
    • classifying bridge condition,
    • risk based methods of bridge management,
    • modelling deterioration rates,
    • prioritising bridge repair,
    • bridge management systems

County Surveyors Society

Afternoon Discussion Topics

• Levels of funding - recently increased - please keep it up!!
• Liaison with other owners - BOF?
• Standards for bridges on local roads - more involvement by Highways Agency?
• Bridge condition indicators
• Materials & details eg waterproofing, joints surfacing materials - aim for low maintenance structures.

Department for Regional Development (Northern Ireland)

Electrochemical Chloride Extraction

A field trial of ECE was carried out by Dr Abid Abutair (University of Ulster) on a heavily contaminated bank seat of the M1 River Bann Bridge in Craigavon in 1997. The bridge was constructed in the late 1960's.

Evaluation of the desalination process required the use of a unique programme based on the University of Ulsters porewater extraction technique.

The analysis of the porewater provides the most useful and indepth analysis of the prior and post treatment chemical status of the concrete.

While ECE is a well known technique this demonstration proved successful at this site in reducing chlorides to levels that would ensure that reinforcement corrosion ceased with the novel porewater extraction technique being the main feature for monitoring purposes in the study.

Testing of Ballymacarrett Viaduct Beams (Belfast)

This structure was built in 1958 and demolished in 1997 due to the construction of the Belfast Cross Harbour Bridge scheme.

As prestressed concrete structures are known to undergo time dependent changes due to loss of prestress and possible deterioration of the concrete demolition of the structure offered an opportunity to measure how the bridge beams had performed over their 40 year life and to compare this performance with that predicted.

Dr David Sloan (Queens University, Belfast) carried out tests on precast prestressed concrete beams selected for this study.

In summary:

1. The beam concrete was found to be of high quality with no significant carbonation
2. The prestressing steel was found to be in excellent condition apart from a light coat of surface rust. The grout in the ducts was well compacted with no evidence of voids.
3. The beams behaved elastically up to working load moment and had a recovery of deflection after loading of 97.7%. In the ultimate limit state load factors of 2.3 & 2.1 were obtained on working load and
4. Over the 40 year life of the beams it was concluded that there had been no significant loss of prestress over and above the original assumed losses.

Highways Agency

HA Structures R & D: 2000/01

Around 100 projects including call-off advice.
Budget : Approx 2m.

• HA structures research areas
• Non-destructive testing and monitoring techniques of highway structures
• Risk and reliability methods for bridge management
• Improving knowledge of structural behaviour
• Research into new materials
• Investigation into fire safety of road tunnels
• Best Practice for Bridge Management

• Monitoring of Integral Bridges
• Precast "Dog Bone" Foundations
• Structural Use of Plastic Piles
• Revisions to British Standard 5400 Part 3
• Investigating the Long Term Performance of New Materials
• The Potential for Timber Bridges
• Fire Sprinkler Type Systems in Road Tunnels
• Non Destructive Testing (NDT)

HA Website http://www.highways.gov.uk/

Compendium of Highways Agency Research (1994 1999)
Forward look programme of R & D projects planned in a particular financial year.

Future Main Structures Issues affecting HA

• Implementation of any recommendations from the Study of Roads Advisory and Standards Setting.
• Outcome of The Study Group on Structural Design Codes in Construction (Chairman: Les Clark).
• Implementation of revised Structures Management procedures and new Structures Management Information System (SMIS).
• Implementation of Steady State Assessment Programme.
• Preparations for implementation of Eurocodes.
• 10 year Plan.

• UK Roads Advice and Standards Steering Group (UKRASG).

London Underground

Solution Development

• Arch bridges - TRL programme (complete)
• CFRC
  • Joint Industry Project
  • PIT & LINK Programme
  • Concrete Society Manual
• Monitoring
• Rivet Shear

Railtrack

RailTrack Research Program

No online abstract for reasons of confidentiality.

Afternoon Discussion Topics

• Composite strengthening (particularly of metallic structures) including
  
  1. Chris Burgoyne's ideas on the use of fibre ropes
  2. Railway specific concerns re carbon fibre composites
  3. Fatigue
• Arch serviceability
• New/novel materials such as aluminium and composites for entire structures
• Management systems
• Scour monitoring
• Vehicular strikes on both low bridges and bridge parapets
• Condition monitoring

Scottish Executive

Development of a new bridge acquisition and maintenance policy

• The monitoring of chloride into structural concrete
• Deformation measurements using DGPS.

National Assembly for Wales

Current research topics

The development of a new bridge acquisition and maintenance policy will be described with reference to Departmental Objectives, a new definition of Asset, the requirements of Resource Accounting and Budgeting and lessons already learnt from experience of the Assessment and Strengthening Programme.