Corrosion

Local corrosion on girder edge

Broken girder edge due to corrosion

Anchor of PC cables
inside the girderSag at the mid-span hinge position
Sag at the central hinge

Horizontal metalbearing

Built in 1971
L = 161.65 m (33.5 + 72 + 53)
22002 & 2012 Specifications for Highway Bridges
1.

International trend in promoting performance-based codes to easetrade barriers (ISO2394 (1998))

2.

Flexible acceptance to innovative technologies in construction projects
to meet diversifying technical proposals

3.

Needs for durable and maintenance-friendly structures

Advent of Performance-based Specifications
1) From prescriptive to performance-based: Required performance criteria
were philosophically set out, as requested by ISO2394
2) Performances comes first and mandated. Standards are regarded as
acceptable solutions. Alternatives can be confirmed to see if thealternatives offer equivalent or greater performances than the standards.
3) Prescriptions for durability demands on fatigue in steel members, andchloride ingress in concrete members, durable RC deck slab design etc wereshown.
4) A maintenance plan and relevant countermeasures are required in initialdesign.

A big Issue in promoting innovative
procurements:

How to evaluate the durability & establish QA/QC processes
in construction for new materials and structuresI-95 Mianus River Bridge

CONNOR, R.J. et al., Inspection andManagement of Bridges with FractureCritical Details, NCHRP SYN. 354, 2005

5

Sudden collapse of de la Concorde Overpass,
Quebec, Canada, in 2006
RC drop-in girder, L = 60.8 m
Built in 1970 and collapsed in 2006 (36-year old)
Cause: Corrosion of reinforcement bars, inadequate
reinforcement arrangement, & insufficient amount ofreinforcement, resulting in shear failure of a drop-in span

Ref: ”Commission of Inquiry into the Collapseof a Portion of the de la Concorde Overpass”

Collapse of I-70 Bridge, US, in 2005
Post-tension PC bridge,Length = 26 m
Built in 1950 and suddenly
collapsed in 2005 (55-year old)
Cause: Corrosion and failure in PCcables

出典：http://www.post-gazette.com/pg/05362/628813.stm

Collapse of Ynys-y-Gwas Bridge, UK, in 1985
Post-tension & segmental girder PC bridge,

Length = 18.3 m

Built in 1953 and suddenly collapsed in 1985 (32-year old)
Cause: 1. Corrosion and failure in PC cables
2. Insufficient grouting inside sheaths  Prohibited toconstruct PC bridges with grouting until 1996
3. De-icing salt in winterhttp://www.youtube.com/watch?v=PUg_EqQN6Gg&translated=1

Malfunctioning of two girders in Hoan Bridge(2000.12)
3-span plate girder bridgewith 3 main girders
Fatigue crack starting froma welding part of gusset toattach a lateral member

HOAN BRIDGE FORENSIC INVESTIGATIONFAILURE ANALYSIS FINAL REPORT, June 2001,
Wisconsin DOT & FHWA

92002 Specifications for Highway Bridges
1.

International trend in promoting performance-based codes to easetrade barriers (ISO2394 (1998))

2.

Flexible acceptance to innovative technologies in construction projects
to meet diversifying technical proposals

3.

Needs for durable and maintenance-friendly structures

Advent of Performance-based Specifications
1) From prescriptive to performance-based: Required performance criteria
were philosophically set out, as requested by ISO2394
2) Performances comes first and mandated. Standards are regarded asacceptable solutions. Alternatives can be confirmed to see if thealternatives offer equivalent or greater performances than the standards.
3) Prescriptions for durability demands on fatigue in steel members, andchloride ingress in concrete members, durable RC deck slab design etc wereshown.
4) A maintenance plan and relevant countermeasures are required in initialdesign.