Landside Buttress

Measure related to shoreline stabilization opportunities to address seismic risk

Looking for more? Head back to the Measures Explorer to check out other flood and seismic measures.


A landslde buttress to stabilize the shoreline would be accomplished by deep mixing of situ soils with cement as shown here - San Francisco, CA © Fugro


DESCRIPTION: Strengthen a deep block of weak soil landside of the existing bulkhead to stabilize the shoreline, reduce earthquake induced lateral spreading, and eliminate liquefaction of Embarcadero fill resulting in a stable and earthquake resilient foundation. The improved soils would also mitigate liquefaction-induced settlements within its footprint.



SHORELINE STABILIZATION:
TYPE: Geotechnical
SHORELINE LOCATION:
Landside




DESIGN LIFE:

ADAPTABILITY:

IMPACT ON THE WATERFRONT:

CONSTRUCTION COST:
100+ Years

Medium

Major Landside Intervention

Very High





SEISMIC HAZARDS MITIGATED:
SEISMIC PERFORMANCE IMPROVED:





Lateral Spreading
Liquefaction

StructuresUtilities & Transportation




MEASURES COMPATIBILITY:
Flood
Seismic
Floodwalls
Levees (Raised Roadway)
Bulkhead Wharf Retrofit

Utility Replacements




CONSIDERATIONS:

ADVANTAGES:

DISADVANTAGES:





  • Width of buttress defined by depth of Young Bay Mud which varies along the waterfront.
  • Very effective in areas of deep Young Bay Mud.

  • Mitigates both lateral spreading and liquefaction-induced settlement.
  • Provides stable zone to raise the roadway or build flood protection.
  • Waterfront buildings can likely remain occupied during construction.
  • No in-water work.



  • Most construction impact to the Embarcadero.
  • Requires full replacement of surface infrastructure & utilities.
  • Long construction duration.
  • Aging Bulkhead wall and wharves still need rehabilitation and some earthquake strengthening.



CONSTRUCTION IMPACTS TO THE PUBLIC:

SEA LEVEL RISE ADAPTATION OPPORTUNITIES:



  • Construction would require lengthy closure of northbound Embarcadero and Promenade.
  • Southbound Embarcadero may be changed to one lane in each direction.
  • Muni light rail may need to be closed to provide traffic/bike/pedestrian circulation space.

  • The new engineered land could serve as a foundation for a future levee in the form of a raised roadway to protect the City from sea level rise.
  • Also, the new land would provide an inherent barrier to limit the influence of rising sea levels on groundwater elevations.



DESIGN CONSIDERATIONS:

  • The width of improved soil necessary to effectively buttress the existing seawall would depend upon the depth from the ground surface to the competent soil layers below.
  • As this depth varies along the waterfront, the width of improved soil would vary.


SITE-SPECIFIC CONSIDERATIONS:

  • Areas with a high concentration of utilities and/or large sewer structures would interrupt the buttress and may compromise its effectiveness.
  • The width of improved soil between Pier 3 and Pier 19 would likely be controlled by the location of the transport storage box.


URBAN DESIGN CONSIDERATIONS:

  • Construction work to demolish surface infrastructure and to relocate utilities may provide an opportunity to rebuild the Embarcadero and promenade following a new design.


HISTORICAL RESOURCE CONSIDERATIONS:

  • This measure would not impact any historical buildings and marine structures.


INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • This measure would require extensive utility relocation work and demolition and restoration of northbound Embarcadero and promenade.
  • More than one ground improvement technique may be required due to the rock dike versus fill. Large construction footprint would be required.



Other Types of Seismic Measures:

Click the images and links below to explore other types of seismic measures.

Shoreline Stabilization
Nearshore ButtressDrilled ShaftsSuper Bulkhead Wharf



Targeted

Bulkhead Wharf RetrofitLiquefaction Mitigation



Head back to the Measures Explorer to check out flood measures.


Measure related to shoreline stabilization opportunities to address seismic risk

Looking for more? Head back to the Measures Explorer to check out other flood and seismic measures.


A landslde buttress to stabilize the shoreline would be accomplished by deep mixing of situ soils with cement as shown here - San Francisco, CA © Fugro


DESCRIPTION: Strengthen a deep block of weak soil landside of the existing bulkhead to stabilize the shoreline, reduce earthquake induced lateral spreading, and eliminate liquefaction of Embarcadero fill resulting in a stable and earthquake resilient foundation. The improved soils would also mitigate liquefaction-induced settlements within its footprint.



SHORELINE STABILIZATION:
TYPE: Geotechnical
SHORELINE LOCATION:
Landside




DESIGN LIFE:

ADAPTABILITY:

IMPACT ON THE WATERFRONT:

CONSTRUCTION COST:
100+ Years

Medium

Major Landside Intervention

Very High





SEISMIC HAZARDS MITIGATED:
SEISMIC PERFORMANCE IMPROVED:





Lateral Spreading
Liquefaction

StructuresUtilities & Transportation




MEASURES COMPATIBILITY:
Flood
Seismic
Floodwalls
Levees (Raised Roadway)
Bulkhead Wharf Retrofit

Utility Replacements




CONSIDERATIONS:

ADVANTAGES:

DISADVANTAGES:





  • Width of buttress defined by depth of Young Bay Mud which varies along the waterfront.
  • Very effective in areas of deep Young Bay Mud.

  • Mitigates both lateral spreading and liquefaction-induced settlement.
  • Provides stable zone to raise the roadway or build flood protection.
  • Waterfront buildings can likely remain occupied during construction.
  • No in-water work.



  • Most construction impact to the Embarcadero.
  • Requires full replacement of surface infrastructure & utilities.
  • Long construction duration.
  • Aging Bulkhead wall and wharves still need rehabilitation and some earthquake strengthening.



CONSTRUCTION IMPACTS TO THE PUBLIC:

SEA LEVEL RISE ADAPTATION OPPORTUNITIES:



  • Construction would require lengthy closure of northbound Embarcadero and Promenade.
  • Southbound Embarcadero may be changed to one lane in each direction.
  • Muni light rail may need to be closed to provide traffic/bike/pedestrian circulation space.

  • The new engineered land could serve as a foundation for a future levee in the form of a raised roadway to protect the City from sea level rise.
  • Also, the new land would provide an inherent barrier to limit the influence of rising sea levels on groundwater elevations.



DESIGN CONSIDERATIONS:

  • The width of improved soil necessary to effectively buttress the existing seawall would depend upon the depth from the ground surface to the competent soil layers below.
  • As this depth varies along the waterfront, the width of improved soil would vary.


SITE-SPECIFIC CONSIDERATIONS:

  • Areas with a high concentration of utilities and/or large sewer structures would interrupt the buttress and may compromise its effectiveness.
  • The width of improved soil between Pier 3 and Pier 19 would likely be controlled by the location of the transport storage box.


URBAN DESIGN CONSIDERATIONS:

  • Construction work to demolish surface infrastructure and to relocate utilities may provide an opportunity to rebuild the Embarcadero and promenade following a new design.


HISTORICAL RESOURCE CONSIDERATIONS:

  • This measure would not impact any historical buildings and marine structures.


INSTALLATION AND CONSTRUCTABILITY CONSIDERATIONS:

  • This measure would require extensive utility relocation work and demolition and restoration of northbound Embarcadero and promenade.
  • More than one ground improvement technique may be required due to the rock dike versus fill. Large construction footprint would be required.



Other Types of Seismic Measures:

Click the images and links below to explore other types of seismic measures.

Shoreline Stabilization
Nearshore ButtressDrilled ShaftsSuper Bulkhead Wharf



Targeted

Bulkhead Wharf RetrofitLiquefaction Mitigation



Head back to the Measures Explorer to check out flood measures.


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