8th street bridge community information session november 19th, 2015

8th Street BridgePublic Information

SessionNovember 19th, 2015

Agenda Welcome & Opening Comments (Mayor Rick

Chrest)

Presentation (Coenraad Fourie, Manager of Development & Transportation)

Questions and Answer (Mayor Rick Chrest & City Councillors

Wrap-up and Next Steps

Background History Structure consists of 2 distinct sections:

– 1934 section - north of railway tracks (81 years old);

– 1968 section – spans over railway tracks (47 years old)

Structure is at end of life, typical maximum life expectancy is 50 years

Studies & Maintenance

1984 – Condition Assessment leading to:

– replacement of asphalt surfacing with 100mm concrete deck surfacing for total of 275mm and

– repairs to substructure and – expansion joints

(Reid Crowther & Partners Ltd.)

Studies & Maintenance (cont.) 1992 – Complete Condition Assessment leading to:

– Partial and full depth deck repairs to 1968 and 1934 bridge sections;

– penetrating sealer applied to deck and sidewalks to slow down deterioration;

– repairs to bridge deck supports at locations 4, 7 and 10;

– repairs to southern bridge (1968 section) abutment / deck support structure;

– repairs to western bridge deck support beam and walkway support beams on 1934 (northern) section;

– expansion joint repairs(Reid Crowther & Partners Ltd.)

Studies & Maintenance (cont.)

1999 – Detailed condition assessment revealing:

– High corrosion potential of steel reinforcement;– Shear cracks in bridge support beams

(Reid Crowther & Partners Ltd)

1999 - Bridge Inspection Programme launched with biannual inspections performed from 2000 to 2007 by Reid Crowther & Partners and Earth Tech revealed:

– continuously increasing corrosion potential;– bridge deck chloride contents well in excess of acceptable

threshold values i.e. accelerated deterioration potential

Studies & Maintenance (cont.)

2011 & 2012 – Detailed condition assessment by Dillon Consulting Ltd. reiterates increasing corrosion potential and escalating chlorides

September 2015 – City commissions Dillon Consulting Ltd. for structural evaluation which leads to bridge closure.

October 2015 – Dillon Consulting Ltd. retained for cost estimates of rehabilitation options;

November 2015 –City Engineer presents options to City Council; City Council holds Public Information Session

8th Street Bridge Current Condition

Option #1: Rehabilitate to allow limited vehicle

traffic Estimated Cost of $1.325M

Estimated project timeline of 2 – 3 years

Advantages– Restores limited vehicle connectivity

Option #1: Rehabilitate to allow limited vehicle

traffic (cont.) Disadvantages

– Will require additional measures to limit traffic to 4 tonnes

– Would extend the structure service life by only 3 to 5 years

– High uncertainty and potentially significant cost escalations due to deteriorated sections

– Structure does not meet current design standards– Final demolition cost (currently $2.3 million) escalates

further

Option #2: Demolish & Replace Demolition cost of $2.3M and then $28. 5M to

$33M for replacement (depending on location) = Total estimated cost of $31M to $35M


Advantages– New structure with minimum 50-year design life

Option #2: Demolish & Replace (cont.)

Disadvantages– Completion will likely coincide with new Daly

Overpass– High capital cost, low return on investment

Option #3: Demolish and replace with

pedestrian/cyclist crossing Estimated Cost of $2.3M demolition, plus $9.5M

for pedestrian / cyclist structure = Total Cost of $11.8M


Advantages– Maintains north south connectivity and access

for pedestrians/cyclists– New structure will meet current standards

Option #3: Demolish and replace with pedestrian/cyclist crossing (cont.)

Disadvantages– No vehicular connection– High capital cost

Option #4: Demolish Estimated Cost of $2.3M

Estimated timeline of 1 – 2 years

Advantages– Mitigates public safety concerns – Eliminates future continued maintenance and

monitoring costs

Disadvantages– Community impacts

Questions ?

8th street bridge community information session november 19th, 2015

Government & Nonprofit