chc staff briefing 4_27_10.ppt
TRANSCRIPT
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Los Angeles
Cultural Heritage Commission
6th Street Viaduct
Bridge Improvement Program
CHC Staff Update
April 27, 2010
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Todays Agenda
1. Introductions
2. Environmental Status & Milestone Dates
3. CHC DEIR/EIS Comments/Replies
4. Recap of ASR Workshop
5. Preferred Alternative
6. SHPO MOA
7. CHC May 20th Hearing
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Status of 6th ST EIR/EIS
DEIR/EIS circulated June 16 - August 24, 09 25 written comments received
Responses to all comments included in Draft
FEIR/EIS Two additional Bridge Concepts (1A and 4A)
evaluated in Draft FEIR/EIS
Preferred Alternative workshop conducted
on 9/29/09
Draft FEIR/EIS is awaiting Caltrans
Headquarters and Legal review
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Next Environmental Milestones
MOA Concurrence by SHPO 5/14/10
Cultural Heritage Commission Hearing 5/20/10
BPW Public Hearing 5/31/10
Caltrans Approval of Final EIR/EIS
(Head quarters & Legal)
7/31/10
Community Advisory Committee (Mtg. #10) TBD (June)
City Council Committee Hearings
Public Works
Budget and Finance
Transportation
TBD
(June/July/Aug 2010)
City Council Approval/Certification 8/31/10
File CEQA Notice of Determination (NOD) 9/1/10
Notice of Availability (NOA) in Federal
Register
10/1/10
Approve NEPA Record of Decision (ROD) 10/1/10
CEQA Approvals City of Los Angeles, Lead Agency
NEPA Approvals Caltrans, Lead Agency
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CHC Comments and Replies
DEIR/EIS1. Designation as Historic-Cultural Monument
2. Retaining HCM Status
3. Full Replication/Reconstruction Alternative
4. Proposed Viaduct Width
5. Partial Preservation Alternative
6. Mitigation Measures
7. Reuse of Steel Arches
8. Architectural Elements that are not part of Viaduct
9. AASHTO Guidelines for Historic Bridges
10. MOA with SHPO
11. SHPO Concurrence
12. CAC Vote
13. CAC Meeting Minutes
14. Mailing List Information
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ASR Attack is triggered by:1. Reactive form of silica in aggregates
2. Sufficient alkali (Na or K) in cement
3. Sufficient available moisture
Alkali-Silica Reaction
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ASR Attack of Concrete Material
ASR deterioration is throughout structure
Columns & foundations are most damaged
Repairs have been ineffective
ASR will continue
Light Damage Moderate to Severe Damage
Moderate Damage Severe Damage
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ASR Treatments - Existing Structures
Slow the Reaction
Epoxy Injection Methacrylate Injection
Lithium Injection
Provide 3-D Confinement Pressure
Replace Most Severely Damage Members
Re lace Structure
Surface of Girder
Penetration intoMember
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Alternative 1 No Action
Alternative 2 Retrofit Infill Walls & Heavy Steel Casing
Substructure Replacement
Alternative 3 Replacement Alignments 3A, 3B, 3BM, 3C
Bridge Concepts 1 5, 1A and 4A
Project Alternatives for
Environmental Assessment
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Provides Seismically Safe Structure with a 75 yr Design Life
Retrofit not Preferred as it does not Stop or Mitigate ASR
High Life Cycle Cost
Doesnt Correct Deficiencies
Doesnt Meet Railroad Operator Requirements
Provides only for No-Collapse Criteria, Likely Significant Damage
After the Design Earthquake Event
Preferred Alternative
Replacement
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Staffs Recommended Alternative
Concept 4ACorridor 3B
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Status of MOA
10/27/09 - PDT submitted Draft MOA toCaltrans for HQ review
1/12/10 - Caltrans HQ submitted Draft MOA
for SHPO review
3/23/10 SHPO requested to add the drawing
review in the MOA
4/22/10 SHPO requested to add drawing
review at various stages of bridge design
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May 20th Meeting
Time Allocation Topics to be Address
Other