CHC staff briefing 4_27_10.ppt

8/22/2019 CHC staff briefing 4_27_10.ppt

1/13

Los Angeles

Cultural Heritage Commission

6th Street Viaduct

Bridge Improvement Program

CHC Staff Update

April 27, 2010


2/13

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


3/13

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


4/13

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


5/13

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


6/13

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


7/13

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


8/13

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


9/13

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


10/13

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


11/13

Staffs Recommended Alternative

Concept 4ACorridor 3B


12/13

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


13/13

May 20th Meeting

Time Allocation Topics to be Address

Other

CHC staff briefing 4_27_10.ppt

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