CLINTON BASIN BULKHEAD DESIGN CRITERIA AND PRELIMINARY DESIGN

AUGUST 2021

EXISTING CONDITION

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OVERVIEW OF CLINTON BASIN IMPROVEMENTS

Steel Sheetpile Bulkhead

Future Wharf

(N) Fill

Promenade Wharf

Retaining Wall

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Design Codes and Standards• Design Codes and References

• California Building Code 2016 • ASCE 7-10 • NCHRP 611

• Seismic Load Combinations per ASCE 7-10:• 1.6H + E (LRFD)• 1.0H + 0.7E (ASD)• H = Earth Pressure and Hydrostatic and Surcharge• E = Seismic Increment, (NCHRP 611, from ENGEO)

• Seismic Design Criteria:• Design Basis Earthquake (DBE)• Conservatively used R=1 which means entire bulkhead

system will remain elastic during design earthquake event

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Bulkhead wall overview

• Figure showing bulkhead improvements

• Steel sheetpile bulkhead wall ~258 ft long

• Concrete deadman anchor –245 ft long

• Tie-rod and waler system to brace bulkhead

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Bulkhead Elevation

• Bulkhead elevation• Mudline varies along bulkhead• Retained height deepest at center of channel• Retained height decreases closer to the

channel edges

(E) Mudline(N) FILL

YOUNG BAY MUD / DEPOSITS

OLD BAY CLAY

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Bulkhead Cross-section• Figure showing

bulkhead cross-section

• Section showing general soil stratigraphy

• Tie-rod braces sheetpile and anchors back to the concrete deadman anchor

• Soil around concrete deadman to be replaced with (N) Compacted Fill

(N) FILL

YOUNG BAY MUD / DEPOSITS

OLD BAY CLAY

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Installation SequenceStep 1: Install steel sheetpile wall Step 2: Dewater behind wall

Step 3: Add new fill behind sheetpile wall. Add surcharge to consolidate Young Bay Mud and deposits.

Step 4: Install deadman, and tie-rod with isolation sleeve. Add fill behind wall and surcharge as necessary

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Bulkhead loading• Loading components provided by ENGEO

• Earth Pressure• Surcharge• Hydrostatic• SeismicWe checked the following loading scenarios:1. Temporary, During Construction2. Static, with surcharge3. Seismic

Load Combinations:[ASD] 1.0*Dead + 1.0*Live + 1.0*Earth Pressure + 1.0*Hydrostatic + 0.7*Seismic[LRFD] 1.2*Dead + 1.0*Live + 1.6*Earth Pressure + 1.6*Hydrostatic + 1.0*Seismic

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Global Stability - Overview

• Global stability check for deep failure modes

• To ensure sheetpile Tip EL. is adequate

• Performed for:• Temporary surcharge• Static• Seismic

• Evaluated circular and non-circular surfaces

• Actual FOS exceeded minimum FOS. No deep failure expected with given sheetpile length

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Global Stability - Results• FOS for all cases are adequate

FOS Min. FOS CheckTemp – Circular 1.4 1.1 OK!Temp – Noncircular 1.3 1.1 OK!Static – Circular 2.8 1.5 OK!Static – Noncircular 2.1 1.5 OK!Seismic – Circular 1.6 1.1 OK!Seismic – Noncircular 1.3 1.1 OK!

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Bulkhead analysis model• Bulkhead modeled in SAP2000• Sheetpile modeled as shell elements

stiffness only in vertical direction• Waler and tie-rods modeled as frame

elements• Deadman anchor forces factored for

LRFD design• Loads applied as discussed on earlier

slides • Passive pressure:

• Constant 200 psf within Deposits• 1000 psf at EL. -25 ft, increases by

175 psf/ft

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Temporary case during construction• Bulkhead analysis in PYWall• ASD loading for hydrostatic

loads• Bending = 133 kip-ft/ft

CASE DemandSteel sheetpile

option CapacityDCR

(<1.0 OK)Construction 133 kip-ft/ft PZ40 180 kip-ft/ft 0.74

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Bulkhead bending demands – Static and Seismic

• Vertical Bending (ASD)• [Static] 95 kip-ft/ft• [Seismic] 115 kip-ft/ft

CASE DemandSteel sheetpile

option CapacityDCR

(<1.0 OK)Static 95 kip-ft/ft PZ40 180 kip-ft/ft 0.53

Seismic - DE 115 kip-ft/ft PZ40 180 kip-ft/ft 0.74

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Bulkhead shear – Static and Seismic• Vertical Shear (ASD)

• [Static] 12 kip/ft• [Seismic] 14 kip/ft

CASE DemandSteel sheetpile

option CapacityDCR

(<1.0 OK)Construction 15 kip/ft PZ40 74 kip/ft 0.20

Static 12 kip/ft PZ40 74 kip/ft 0.16Seismic - DE 14 kip/ft PZ40 74 kip/ft 0.19

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Tie-rod and Wale

Demand Grade Size CapacityDCR

(<1.0 OK)

Tie-rod Static 100 kip 75 2.25 in. dia 180 kip 0.56

Seismic - DE 120 kip 75 2.25 in. dia 180 kip 0.67

Wale Seismic - DE 75 kip-ft 36 2MC13x50 199 kip-ft 0.38

• Wale (2MC13x50)• Tie-rod:

• 2.25 in. dia. Gr 75• Installed with Isolation sleeve

to protect from ground settlement

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Deadman Anchor

Component Case Demand Depth Size Capacity FOS

Deadman(SLR) Static Stability 10.9 kip/ft 11 ft 7 ft x 2.5 ft 17.0 kip/ft 1.57

Seismic - DEStability 13 kip-ft 34 kip-ft 2.56

• Deadman: 7 ft deep:• Both Static and Seismic FOS

OK!• 75 ft offset from bulkhead• Fill requirements around

Deadman for passive resistance

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SUMMARY• The bulkhead is a 23 ft. tall sheet pile wall braced by waler and tie rods.• Sea Level Rise has been adequately considered using the project criteria

that was approved by ECRB in 2015• The design was performed per CBC and conservatively used R=1, which

means entire bulkhead system will remain elastic in the design earthquake event and the site is fully occupiable after the earthquake.

• Bulkhead sheet piles have adequate capacity for temporary and permanent conditions, for both static loads and seismic loads

• Tie-rods and deadman have adequate capacity for both static and seismic conditions

• Global stability analysis (SLIDE), using both circular and non-circular methods, confirmed the global stability of the bulkhead in the temporary and permanent conditions for both the static loads and seismic loads.

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THANK YOUQUESTIONS?