Pola Seismic Code 2010
Pola Seismic Code 2010
Pola Seismic Code 2010
2
POLA SEISMIC CODE 2010
FOREWORD
In 2004, the City of Los Angeles Harbor Depart, also known as the Port of Los Angeles (POLA),
adopted The Port of Los Angeles Code for Seismic Design, Upgrade and Repair of Container
Wharves dated May 18, 2004 as the seismic code for container wharf structures at the Port of
Los Angeles. That document is referred to as POLA Seismic Code 2004.
Since 2004, POLA has endeavored to improve and update the POLA Seismic Code 2004. This
endeavor has resulted in an updated document for the seismic code for marginal container wharf
structures. Upon adoption by the City of Los Angeles Harbor Department, the updated
document will come into effect and supersede the POLA Seismic Code 2004. The updated
document will be referred to as POLA Seismic Code 2010.
POLA Seismic Code 2010 provides updates and revisions to the POLA Seismic Code 2004. The
POLA Seismic Code 2004 has been revised and reformatted to include changes in the seismic
design requirements and to address review comments from the public during an industry-wide
workshop held in 2005 cosponsored by POLA and the American Society of Civil Engineers
(ASCE). The requirements in the POLA Seismic Code 2004 have been updated to reflect the
conclusions of experimental research and technical studies conducted since its publication.
Other additional revisions were made in a continued effort to improve the code requirements for
marginal container wharf structures at the Port of Los Angeles.
Upon adoption of the POLA Seismic Code 2010, any variances and modifications not in
compliance with the POLA Seismic Code 2010 will require explicit approval by POLA.
ii
TABLE OF CONTENTS
FOREWORD.................................................................................................................................. i
TABLE OF CONTENTS ............................................................................................................ iii
LIST OF TABLES ....................................................................................................................... iv
LIST OF FIGURES ..................................................................................................................... iv
STANDARDS AND GUIDELINES ............................................................................................ v
DEFINITIONS ............................................................................................................................. vi
SYMBOLS AND NOTATIONS ............................................................................................... viii
1Seismic Design of New Container Wharves ............................................................................ 1
1.1 Purpose ............................................................................................................................ 1
1.2 Scope ............................................................................................................................... 1
1.3 Performance Requirements ............................................................................................. 1
1.3.1 Ground Motions....................................................................................................... 1
1.3.2 Strain Limits ............................................................................................................ 2
1.4 General Seismic Criteria ................................................................................................. 4
1.4.1 Wharf ....................................................................................................................... 4
1.4.2 Embankment and Dike ............................................................................................ 4
1.4.3 Utilities and Pipelines .............................................................................................. 4
1.5 Load Combinations ......................................................................................................... 4
1.6 Analytical and Design Requirements .............................................................................. 5
1.6.1 Seismic Mass ........................................................................................................... 5
1.6.2 Material Properties .................................................................................................. 5
1.6.3 Modeling Requirements .......................................................................................... 5
1.6.4 Displacement Demand and Capacity....................................................................... 7
1.6.5 Piles ....................................................................................................................... 11
1.6.6 Deck ....................................................................................................................... 15
1.6.7 Detailing Requirements ......................................................................................... 17
1.7 Geotechnical and Soil-structure Interaction Requirements ........................................... 17
1.7.1 Liquefaction ........................................................................................................... 17
1.7.2 Slope Stability and Seismically Induced Lateral Spreading.................................. 17
1.7.3 Lateral Spreading-free Field .................................................................................. 18
1.7.4 Seismically Induced Settlement ............................................................................ 19
1.7.5 Soil-structure Interaction ....................................................................................... 19
1.7.6 Earth Pressure ........................................................................................................ 19
2 Upgrade and Repair Criteria for Existing Wharves ............................................................ 21
2.1 Purpose and Scope ........................................................................................................ 21
2.2 Seismic Upgrades .......................................................................................................... 21
2.3 Structural Repairs .......................................................................................................... 21
2.4 Nonstructural Repairs .................................................................................................... 22
iii
LIST OF TABLES
Table 1-1: Ground Motions ............................................................................................................ 1
Table 1-2: Seismic Piles Top Plastic Hinge Strain Limits .............................................................. 2
Table 1-3: Non-seismic Piles Top Plastic Hinge Strain Limits ...................................................... 2
Table 1-4: In-ground Plastic Hinge Strain Limits for Seismic and Non-seismic Piles .................. 3
Table 1-5: Plastic Hinge Length ................................................................................................... 11
LIST OF FIGURES
Figure 1-1: Modeling of Pile-to-Deck Connection (Not-to-Scale) ................................................. 6
Figure 1-2: Multi-modal Spectral Analysis .................................................................................... 8
Figure 1-3: Force-displacement Curve ........................................................................................... 9
Figure 1-4: Curvature Ductility Factor Versus Curvature Ductility Demand .............................. 13
Figure 1-5: Pile Transverse Reinforcement Shear Strength Component ...................................... 14
Figure 1-6: Pile Axial Force Shear Strength Component ............................................................. 14
Figure 1-7: Versus Wharf Unit Length ..................................................................................... 17
iv
CBC
ASCE 7-05
ACI-318
AISC
ASTM
NEHRP
DEFINITIONS
Capacity-protected: Structural elements such as pile caps, deck beams, and deck slabs that are
designed to have a greater capacity than the adjacent ductile members such as piles. Refer to
Section 1.6.6.
Code: The Port of Los Angeles Code for Seismic Design, Upgrade and Repair of Container
Wharves (POLA Seismic Code 2010).
Contingency Level Earthquake (CLE): The seismic event that produces ground motions
associated with a 475-year return period. The 475-year return period ground motions have a 10
percent probability of being exceeded in 50 years.
Design Earthquake (DE): Design earthquake as defined in ASCE 7-05 Section 11.2.
Diameter (Pile Diameter): Diameter of circular cross-section or diameter of circle inscribed
within non-circular cross section.
Dike: Engineered assembly of rock material used to retain fill or cut slopes for container
wharves.
Ductile Design: Design of structural elements that provide significant displacement and rotation
capacity beyond yield strength through the use of detailing, such as confinement. Refer to
Section 1.6.7.
Dynamic Magnification Factor (DMF): A factor to account for effects of higher order modes.
Refer to Section 1.6.4.1f.
Embankment: Fill material or cut slopes protected or stabilized by dike.
Expansion Joint: A joint between two wharf units with a shear key that allows relative
longitudinal movement (movement parallel to shore) but restricts relative transverse movement
(movement perpendicular to shore).
Expected Strength: The strength of a structural member based on the most probable (expected)
material properties. Refer to Section 1.6.2.
Hydrodynamic Mass: Mass of the water around the pile which is accelerated with the
movement of the pile due to action of pressure under seismic load. Refer to Section 1.6.1.
Inertial Load: Loading on the piles from the response of the seismic mass due to seismic ground
acceleration. Refer to Section 1.7.5.1.
Kinematic Load: Loading on the piles from permanent ground deformation. Refer to Section
1.7.5.2.
Linked Wharves: Two or more wharf units that are joined by one or more expansion joint(s).
Lower-bound Lateral Soil Spring: The lowest lateral soil spring representing the softest soil
behavior. Refer to Section 1.7.5.1.
Marginal Container Wharves: Waterfront structures parallel to the shoreline that project from
the land into a body of water used for transfer of containers. Typically, marginal wharves have a
minimum of one row of piles located landside of or close to the dike crest.
vi
Modal Response Spectrum Analysis: Spectral analysis that captures transverse, longitudinal
and rotational modal responses. Refer to Section 1.6.4.1
Non-seismic Piles: Piles that resist no more than 10% of the total lateral seismic load. These
piles are typically located waterside of the dike crest in deeper water and primarily carry vertical
load.
Operational Level Earthquake (OLE): The seismic event that produces ground motions
associated with a 72-year return period. The 72-year return period ground motions have a 50%
probability of being exceeded in 50 years.
Performance-based Design: Design based on specific criteria and performance objectives
associated with acceptable levels of damage at specified levels of seismic hazard.
Pile-deck Joint: The moment resisting connection between the top of the pile and the deck.
Plastic Hinge: The region of the pile where concrete or steel strain exceeds the strain associated
with the yield strength. Refer to Section 1.6.4.2.
Pseudo-static Seismic Slope Stability Analysis: A slope stability evaluation where earthquake
load is represented by an equivalent horizontal static load. Refer to Section 1.7.2.2.
Post-earthquake Static Slope Stability Analysis: A static slope stability evaluation using soil
parameters following an earthquake to account for potential earthquake induced soil strength
loss. Refer to Section 1.7.2.3.
Seismic Mass: The mass of the structure dead load and a portion of the design live load that
contributes to the seismic response. Refer to Section 1.6.1.
Seismic Piles: Piles that resist most of the lateral seismic load. These piles are typically located
landside of or close to the dike crest
Single-mode Transverse Analysis: Spectral analysis that captures the transverse modal
response of the structure.
Soil-structure Interaction (SSI): The process in which the response of the soil influences the
deformation of the structure and the deformation of the structure influences the response of the
soil.
Upper-bound Lateral Soil Spring: The highest lateral soil springs representing the stiffest soil
behavior. Refer to Section 1.7.5.1.
Wharf End Unit: A wharf structure with one expansion joint at one end.
Wharf Unit: A wharf structure between two expansion joints or an independent structure
without expansion joints.
vii
Pile effective shear cross-sectional area (80% of gross cross-sectional area for solid
circular or octagonal piles)
Total cross-sectional area of dowel bars in the pile-deck joint
Cross-sectional area of transverse reinforcement
Width of a wharf unit in feet
Depth from the extreme compression fiber to the neutral axis at flexural strength
Concrete cover plus half the diameter of the transverse reinforcement
Diameter of the pile-deck joint core measured to the centerline of the confinement
steel
Dowel diameter
Dead load in moments, shear forces, or axial forces due to self-weight of the wharf
deck, 1/3 of the pile weight between the deck soffit and 5Dp below the dike surface,
crane self-weight and weight of any permanently attached equipment or fixtures
Diameter of the pile
Earth lateral pressure
Eccentricity between the wharf center of mass and center of rigidity
Earthquake lateral load due to OLE, CLE or DE
Confining steel modulus of elasticity
Wharf total lateral seismic force of the wharf strip considered at d
Specified compressive strength of unconfined concrete at 28 days
Expected concrete compressive strength
Wharf deck member, moment, shear and axial demands
Design moment, shear and axial forces for deck members
Prestress compressive force in pile taken as zero at top plastic hinge
Ultimate strength of prestressing strands
Expected prestressing strand ultimate strength
Nominal yield strength of longitudinal reinforcing steel, dowels, or structural steel
Expected yield strength of longitudinal reinforcing steel, dowels, or structural steel
Nominal yield strength of confining or transverse steel
Expected yield strength of confining or transverse steel
The distance between the top of the pile steel shell and the deck soffit
The distance between the center of the pile top plastic hinge and the center of the
pile in-ground plastic hinge
Time step of the time-history record not more than 0.05-second interval
(0.5 x PGA / gravity) where PGA is the peak ground acceleration in feet/second2
and gravity is 32.2 feet/second2
Curvature ductility factor determined as a function of
Secant wharf stiffness at seismic demand
Initial elastic stiffness of the wharf structure based on cracked section properties
Secant stiffness of the wharf structure at the considered seismic demand
ks at iteration step n
ks at iteration step n-1
Yield acceleration coefficient
L
la
LL
LL
Lp
Lsp
m
mcrane
mcrane,deck
Mn
Mp,in-ground
Mp,top
mseismic
Pa
p-y
Tcrane
Twi
Tws
U
Va
Vc
Vn
Vo
Vp
Vs
Vsk
V
W
c
d
d, j
d, j, m
p, m
t
ti
Distance from the center of the pile top plastic hinge to the pile point of contraflexure
Actual embedment length of dowels anchored in the pile-deck joint
Live load in moments, shear forces or axial forces due to the design uniform live
load
Length of the shortest exterior wharf unit in feet
Plastic hinge length
Strain penetration length
Time-history record number
Mass of crane
Part of the crane mass positioned within 10 feet above wharf deck
Nominal moment capacity
Pile plastic moment capacity at the in-ground plastic hinge including effect of axial
load on piles due to crane dead load
Pile plastic moment capacity at the top plastic hinge including the effect of axial
load on piles due to crane dead load
Seismic mass
External axial load on pile (compression is taken as positive and tension as
negative)
Inelastic lateral soil springs
Translational elastic period of the crane mode with the maximum participating mass
Initial elastic period of the wharf structure based on cracked section properties
Secant period of the wharf structure
Total design load in moments, shear forces or axial forces
Shear strength due to the smallest axial load demand
Concrete shear strength
Pile nominal shear capacity
Pile shear demand
Pile plastic shear
Transverse reinforcement shear strength
Expansion joint shear key force due to OLE, CLE or DE
Total wharf lateral seismic force at the displacement demand determined using
pushover analysis
Effective dead load of the wharf strip considered
Angle between the line joining the centers of the compression zones at top and inground plastic hinges and pile axis
Factor determined as a function of wharf unit length
Displacement capacity corresponding to the performance level considered
Displacement demand corresponding to the earthquake level considered
d at time step j
d at time step j for time-history record number m
The pile plastic displacement capacity due to rotation of the plastic hinge at OLE,
CLE or DE specified strain limit
Displacement of wharf due to transverse excitation
Spectral displacement demand for single-mode transverse response corresponding
to wharf initial elastic period, Twi using 0.05 damping ratio
ix
ts
ts, n
ts, n-1
ts, n-2
X1, X2
X, j, m
XL
XL, j, m
XT
XT, j, m
y
Y1, Y2
Y, j, m
YL
YL, j, m
ys
YT
YT, j, m
c
eff
p
s
sd
smd
p,m
y
p, m
Angle of the critical shear crack with respect to the longitudinal axis of the pile
Pile plastic rotation at OLE, CLE or DE specified strain limit
xi
xii
CHAPTER 1
SEISMIC DESIGN OF NEW CONTAINER WHARVES
1.1 PURPOSE
The purpose of this chapter is to provide seismic code provisions to safeguard life, protect
against major structural failures, limit damages, and minimize economic losses due to seismic
events for new marginal container wharves.
The intent of the provisions provided in this chapter is to achieve performance goals for the
seismic design of new marginal container wharves at three levels of ground motions:
a. Operating Level Earthquake (OLE): No significant structural damage. Damage location to
be visually observable and accessible for repairs. Minimum or no interruption to wharf
operations during repairs may occur.
b. Contingency Level Earthquake (CLE): Controlled inelastic structural behavior and limited
permanent deformations. Damage location to be visually observable and accessible for
repairs. Temporary or short term loss of operations may occur.
c. Design Earthquake Level (DE): Safeguard life and against major structural failures.
1.2 SCOPE
The scope of this chapter is to provide performance-based provisions for the seismic design of
new marginal container wharves at the specified earthquake. General seismic design criteria,
load combinations, analytical and design requirements, detailing requirements, geotechnical and
soil-structure requirements are provided.
In order to achieve seismic performance goals, seismic performance criteria provided in terms of
material strain limits for each earthquake level are specified.
1.3 PERFORMANCE REQUIREMENTS
The design of new marginal container wharf structures shall satisfy the strain limits at the three
levels of ground motions provided in this section.
1.3.1 Ground Motions
Three levels of site-specific ground motions shall be determined for the design of wharf
structures as defined in Table 1-1.
Table 1-1: Ground Motions
Earthquake
Probability of Exceedance
Return Period
50% in 50 years
72
10% in 50 years
475
Page 1 of 22
Design Level
OLE
CLE
c 0.005
sd 0.015
c 0.004
sd 0.015
c 0.006
sd 0.4smd 0.04
c 0.008
sd 0.6smd 0.06
c 0.010
sd 0.015
c 0.025
0.6smd 0.06
c (b)
0.8smd 0.08
(a)
(b)
sd
DE
sd
sd
c (b)
0.8smd 0.08
If the interior of hollow concrete piles is filled with concrete, all strain limits shall be the same as for solid concrete piles.
No limit.
Design Level
OLE and CLE
DE
c 0.005
sd 0.015
sd
c 0.004
sd 0.015
c 0.008
sd 0.6smd 0.06
c 0.010
sd 0.015
c (b)
0.8smd 0.08
(a)
(b)
sd
c (b)
0.8smd 0.08
If the interior of hollow concrete piles is filled with concrete, all strain limits shall be the same as for solid concrete piles.
No limit.
Page 2 of 22
Table 1-4: In-ground Plastic Hinge Strain Limits for Seismic and Non-seismic Piles
Pile
Solid
Concrete
Piles
Round
Hollow
Concrete
Piles(a)
Steel Pipe
Piles
Steel Pipe
Piles
Filled with
Concrete
(a)
(b)
In-ground
Plastic
Hinge
Location
Design Level
OLE
CLE
DE
Hinge form
at depth
10 Dp
c 0.005
p 0.015
Hinge form
at depth
>10 Dp
c 0.008
p 0.015
c 0.012
p 0.025
c (b)
p 0.050
Hinge form
at depth
10 Dp
c 0.004
p 0.015
c 0.006
p 0.025
c 0.008
p 0.025
Hinge form
at depth
>10 Dp
c 0.004
p 0.015
c 0.006
p 0.025
c 0.008
p 0.050
Hinge form
at depth
10 Dp
s 0.010
s 0.025
s 0.035
Hinge form
at depth
>10 Dp
s 0.010
s 0.035
s 0.050
Hinge form
at depth
10 Dp
s 0.010
s 0.035
s 0.050
Hinge form
at depth
>10 Dp
s 0.010
s 0.035
s 0.050
If the interior of hollow concrete piles is filled with concrete, all strain limits shall be the same as for solid concrete piles.
No limit.
Where:
Page 3 of 22
The design of concrete elements shall comply with the provisions of this Code and ACI318-05. The design of steel elements shall comply with the provisions of this Code and
AISC 13th edition.
(1-1)
U = (1K) DL + E + EQ
(1-2)
Where:
U=
Page 4 of 22
(0.5 x PGA / gravity) where PGA is the peak ground acceleration in feet/second2
and gravity is 32.2 feet/second2
DL = Dead load in moments, shear forces, or axial forces due to self-weight of the wharf
deck, 1/3 of the pile weight between the deck soffit and 5Dp below the dike surface,
crane self-weight and weight of any permanently attached equipment or fixtures
LL = Live load in moments, shear forces or axial forces due to the design uniform live
load
E = Earth lateral pressure
EQ = Earthquake lateral load due to OLE, CLE or DE
K=
fce
fye
fyhe
fpue
= 1.3fc
= 1.1fy
= 1.0fyh
= 1.05fpu
Where:
fc=
fy =
fyh =
fpu =
a. The analytical model shall accurately represent distribution of seismic mass, structural
member properties, joint and boundary conditions and contain sufficient nodes and
elements to capture the critical structural seismic responses.
b. The analytical model shall include soil-structure interaction using upper bound and lower
bound lateral soil springs. See Section 1.7. The contribution of soil passive pressure at
the cut-off wall shall not be used to reduce wharf displacement demand or to increase
wharf displacement capacity.
c. Pile cracked section proprieties shall be used based on the expected material properties
provided in Section 1.6.2.
d. The pile effective stiffness shall be determined using the expected material properties
provided in Section 1.6.2.
e. The wharf deck-to-concrete pile connection shall be modeled as shown in Figure 1-1,
which includes, but is not limited to, the following:
1. A node to capture the pile plastic moment capacity at the deck soffit.
2. The length of the first pile element below the soffit shall have reinforced concrete
section properties and be at least 16 inches in length.
3. For piles connected to the deck with dowels, a pile element with the strain penetration
length, Lsp shall be provided as follows:
Lsp = 0.12fyedb
(1-3)
Where:
fye = Expected yield strength of dowels in kips per square inch
db = Dowel diameter
Top of deck
Center of gravity
of deck
Rigid
Lsp
16 inches minimum
Reinforced concrete
section properties
Deck Soffit
Pile Section
Properties
Top of soil
(1-4)
X 1 = XL + 0.3 XT
Y 1 = YL + 0.3 YT
X 2 = 0.3 XL + XT
Y 2 = 0.3 YL + YT
2
2
X 2 + Y 2
(1-5)
(1-6)
(1-7)
Page 7 of 22
Where:
XL =
XT =
YL =
YT =
X1, X2 =
X
YT
YL
XT
Node
XL
Longitudinal
Excitation
Transverse
Excitation
(1-8)
Where:
t = Maximum of ti or ts
ti = Spectral displacement demand for single-mode transverse response
corresponding to wharf initial elastic period, Twi using 0.05 damping ratio
Twi = 2
mseismic
ki
(1-9)
Tws = 2
mseismic
ks
(1-10)
(1-11)
ts
ys
(1-12)
(1-13)
(1-14)
(1-15)
(1-16)
(1-17)
(1-18)
(1-19)
Force
ks,n
ks,n-1
ki
ts,n-2
ts,n-1
Displacement
[ ]
= average [
d = max d , j
d , j
d , j,m
d , j , m = X , j ,m + Y , j ,m
m = 7 records
m =1
X , j ,m = XL, j ,m + XT , j ,m
Y , j ,m = YL, j ,m + YT , j ,m
(1-20)
(1-21)
(1-22)
(1-23)
Where:
XL,j,m= X-axis displacement due to longitudinal excitation, refer to Figure 1-2,
for time step j and time-history record number m
XT,j,m= X-axis displacement due to transverse excitation, refer to Figure 1-2, for
time step j and time-history record number m
YL,j,m = Y-axis displacement due to longitudinal excitation, refer to Figure 1-2,
for time step j and time-history record number m
YT,j,m= Y-axis displacement due to transverse excitation, refer to Figure 1-2, for
time step j and time-history record number m
j=
Time step of the time-history record not more than 0.05-second interval
m=
Time-history record number
1.6.4.2 Displacement Capacity of Wharf
Displacement capacity, c of the wharf shall be determined at OLE, CLE and DE based
on the strain limits provided in Section 1.3.2 using two lateral soil spring conditions:
upper bound and lower bound. Displacement capacity shall be the lesser of displacement
capacity at pile top plastic hinge or displacement capacity at pile in-ground plastic hinge
determined as follows:
c = y + p ,m
(1-24)
p ,m = p ,m H
(1-25)
p , m = L p p , m = L p ( m y )
(1-26)
Where:
y =
Displacement when the considered pile plastic hinge develops
p,m = The pile plastic displacement capacity due to rotation of the plastic hinge
at OLE, CLE or DE specified strain limit
H=
The distance between the center of the pile top plastic hinge and the center
of the pile in-ground plastic hinge
p,m = Pile plastic rotation at OLE, CLE or DE specified strain limit
p,m = Pile plastic curvature at OLE, CLE or DE specified strain limit
Page 10 of 22
m =
y =
Lp =
In-ground Hinge
Lp = 2 Dp
Lp = 2 Dp
L p = 0.3 f ye d b + g
Not applicable
Not applicable
Lp = 2 Dp
Pile
Where:
L = Distance from the center of the pile top plastic hinge to the pile point of contraflexure
fye = Expected yield strength of dowels in kips per square inch
db = Dowel diameter
g = The distance between the top of the pile steel shell and the deck soffit
Dp = Diameter of the pile
1.6.4.3 Crane-wharf Interaction
a. Crane-wharf interaction analysis shall be required if:
Tcrane 2Twi
(1-27)
Where:
Tcrane = Translational elastic period of the crane mode with the maximum
participating mass
Initial elastic period of the wharf structure based on cracked section
Twi =
properties
b. If crane-wharf interaction analysis is required, the displacement demand, d of the
wharf shall be calculated using Nonlinear Time-history Analysis per Section 1.6.4.1g.
1.6.5 Piles
1.6.5.1 Moment Capacity
Pile plastic hinges moment capacities shall be determined using the following:
a. Expected material properties as defined in Section 1.6.2.
b. Largest axial load to obtain highest moment capacity for the design of capacity
protected elements.
Page 11 of 22
c. Smallest axial load to obtain the smallest pile displacement capacity for the design of
piles.
1.6.5.2 Shear
Pile shear demand, Vo shall not be greater than the pile shear capacity Vn :
Vo Vn
(1-28)
Where:
Vo = Pile shear demand
Vn = Pile nominal shear capacity
= Strength reduction factor, 0.85 for OLE and CLE and 1.0 for DE
1.6.5.2.1
Shear Demand
(1-29)
b. Pile plastic shear, Vp shall be determined based on load combinations per Section
1.5 using nonlinear static pushover analysis with upper bound soil springs and
including the effect of the axial load on piles due to crane dead load.
c. In lieu of Section 1.6.5.2.1a, pile shear demand, Vo may be calculated as follows:
Vo = 1.25 (M p ,top + M p ,in ground )/ H
(1-30)
Where:
Mp,top =
Mp,bottom =
H=
1.6.5.2.2
Shear Capacity
Vn = (Vc + Vs + Va )
(1-31)
Vc = k fc' Ae
(1-32)
= 1 +
Vs =
p ,dem
p ,dem
= 1+
y
L p y
Asp f yh (D p c co ) cot( )
s
V a = 0.85 ( Pa + F p ) tan( )
Page 12 of 22
(1-33)
, = 35
(1-34)
(1-35)
tan( ) =
Dp c
(1-36)
Where:
Vc =
Vs =
Va =
k=
Ae =
Asp =
c=
co =
s=
=
Pa =
Fp =
=
3.5
3
2.5
2
1.5
1
0.5
0
0
10
12
14
16
18
20
22
24
26
28
30
Page 13 of 22
Vs
Pile
Neutral
axis
co
c
Dp
Pa
c
Pile
Ground
In-ground
plastic hinge
c
Pa
Neutral axis
Page 14 of 22
1.6.5.3 P- Effects
Additional secondary forces due to the effective dead load and the lateral seismic
displacement demand (P-) shall be calculated at OLE, CLE and DE. P- effects may be
ignored if the following is satisfied:
F
4 d
W
H
(1-37)
Where:
F=
W=
d =
H=
(1-38)
b. Wharf deck member, moment, shear and axial demands, Fd shall be determined based
on load combinations per Section 1.5 using nonlinear static pushover analysis with
upper bound soil springs and including the effect of the axial load on piles due to
crane dead load.
1.6.6.2 Pile-Deck Joint
The pile-deck joint design shall comply with the following requirements:
a. Joint shear principal stresses due to maximum joint forces using load combinations
per Section 1.5 shall comply with ACI-318.
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b. The principal tension stresses shall be less than 12 and the principal compression
stresses shall be less than 0.3 , where is the concrete compressive strength of the
deck.
c. The effective volumetric ratio of confining steel,
around the pile dowels anchored
in the pile-deck joint shall comply with the following:
0.46 Asc
Dla
s = max of
f ye
or 0.016
0.0015 Esh
(1-39)
Where:
Asc = Total cross-sectional area of dowel bars in the pile-deck joint
fye = Expected yield strength of the dowels
D = Diameter of the pile-deck joint core measured to the centerline of the
confinement steel
la = Actual embedment length of dowels anchored in the pile-deck joint
Esh = Confining steel modules of elasticity
1.6.6.3 Expansion Joint
a. The wharf expansion joints shall be designed for the combined effect of seismic
deformation, seismic forces and thermal expansion.
b. The expansion joint shear key force, Vsk due to OLE, CLE or DE shall be calculated
as follows:
1. For wharf units with 400 feet LL 800 feet and 100 feet B 120 feet
V e
Vsk =
LL
(1-40)
Where:
LL = Length of the shortest exterior wharf unit
B = Width of wharf unit
= Factor determined as a function of wharf unit length, refer to
Figure 1-7
V = Total wharf lateral seismic force at the displacement demand
determined using pushover analysis
e = Eccentricity between the wharf center of mass and center of rigidity
2. For wharf units with 800 feet < LL 950 feet or 120 feet < B 140 feet, use
=1.5.
3. For LL > 950 feet or B > 140 feet, Vsk shall be determined using nonlinear timehistory linked wharf analysis.
c. For determining wharf expansion joint shear capacity according to ACI-318, a
reduction factor, of 0.85 shall be used.
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Wharf Unit
Segment
Length,
Length
feet(ft)
Figure 1-7: Versus Wharf Unit Length
1.6.7 Detailing Requirements
a. The minimum concrete cover shall be 3 inches.
Exception: For headed reinforcing bars such as pile dowels or shear stirrups, the cover
may be reduced to 2 inches at the top surface only.
b. All piles shall use ASTM A706 dowels to connect to the deck.
c. The pile-deck joint region for seismic pile shall be confined according to Section 1.6.6.2.
d. Dowels that are extended from piles into wharf deck or beam shall not be bent outwards.
e. If the principal tensile stress in the pile-deck joint region exceeds 3.5
where is the
concrete compressive strength of the deck, additional joint shear reinforcements are
required.
f. The extension of pile prestressing strands into the deck shall not be used for the pile-deck
joint.
1.7 GEOTECHNICAL AND SOIL-STRUCTURE INTERACTION REQUIREMENTS
1.7.1 Liquefaction
Liquefaction potential of the soils in the immediate vicinity of or beneath the wharf structure
and associated embankment or dike shall be evaluated. The strains in the piles induced by
liquefaction effects shall not exceed the strain limits provided in Section 1.3.2.
1.7.2 Slope Stability and Seismically Induced Lateral Spreading
1.7.2.1 Static Slope Stability
a. Static slope stability analysis shall be performed for the embankment or dike.
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b. If liquefaction and/or strength loss of the site soils is expected, residual strength of
liquefied soils strength compatible with the pore pressure generation of potentially
liquefied soil and/or potential strength reduction of clays shall be used in the analysis.
c. The presence of piles shall not be included in the free field evaluations.
1.7.4 Seismically Induced Settlement
Seismically induced settlement shall be addressed in the analysis and design for both
unsaturated and saturated soils and its effects on piles.
1.7.5 Soil-structure Interaction
Inertial and kinematic load conditions shall be analyzed for the pile design as follows:
1.7.5.1 Inertial Load
a. Level ground inelastic lateral soil springs (p-y springs) shall be developed for the site
specific soil conditions.
b. Upper bound estimates of the spring strength and stiffness shall be determined by
multiplying the level ground, p-y springs values by a factor of 2.0.
c. Lower bound estimates of the spring strength and stiffness shall be determined by
multiplying the level ground, p-y springs values by a factor of 0.3.
1.7.5.2 Kinematic Load
a. Kinematic load on seismic piles shall be calculated based on the site-specific
conditions.
Exception: For seismic piles with 24-inch diameter and having an embedment length
of at least 20 feet into the dike, kinematic load need not be considered when the
permanent free field embankment or dike deformations determined per Section 1.7.3
are less than 3 inches for OLE, less than 12 inches for CLE and less than 36 inches
for DE.
b. Deformations shall be restricted so that the pile strains comply with Section 1.3.2.
1.7.5.3 Combination of Inertial and Kinematic Loads
a. The inertial load and kinematic load on seismic piles shall be combined.
Exception: For seismic piles with 24-inch diameter and having an embedment length
of at least 20 feet into the dike, inertial and kinematic pile loads need not be
combined.
1.7.6 Earth Pressure
The earth pressure on the wharf structure resulting from static and seismic load conditions
including the effect of pore water pressure in the backfill shall be calculated.
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CHAPTER 2
UPGRADE AND REPAIR CRITERIA FOR EXISTING WHARVES
2.1 PURPOSE AND SCOPE
This chapter provides requirements for the upgrade and repair of existing container wharves
damaged by seismic or other natural disasters or events.
2.2 SEISMIC UPGRADES
a. Existing wharf seismic upgrade shall comply with the performance requirements of this
Code for the design of a new wharf or as approved by POLA.
b. The overall seismic capacity of existing wharf shall not be reduced by the seismic
upgrade.
c. Existing wharf seismic upgrade also includes embankment and dike.
2.3 STRUCTURAL REPAIRS
a. The damage to existing container wharves caused by seismic or other natural disasters or
events shall be repaired in compliance with the requirements provided in this chapter
based on the level of damage determined by the Damage Ratio. A Damage Ratio,
expressed in a fraction or percent, shall be calculated as follows:
Damage Ratio =
Where:
Estimated Repair Cost is equal to an estimated cost of the repairs required to
restore the damaged wharf members and components to comply with the
requirements of this Code for the damaged wharf unit. Wharf members and
components include decks, beams, piles, cut-off walls, embankments, dikes, all
connections, and other supporting elements.
Estimated Replacement Cost is equal to an estimated cost of replacing the entire
wharf unit.
b. When the Damage Ratio for structural damage does not exceed 0.1 (10%), the structural
damages shall be repaired such that the existing wharf is restored, at a minimum, to the
pre-event condition.
c. When the Damage Ratio for structural damage exceeds 0.1 (10%) but does not exceed 0.5
(50%), the damaged wharf members and components shall be repaired and strengthened
such that all repaired and strengthened structural members, all connections associated
with the damaged structural members, all structural members supported by the damaged
members, and all structural members supporting the damaged members comply with the
performance requirements of this Code for the design a new wharf.
d. When the Damage Ratio for structural damage exceeds 0.5 (50%), the entire existing
wharf shall be repaired and strengthened as necessary such that the entire wharf complies
with the performance requirements of this Code for the design of a new wharf.
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e. Portions of existing wharf may be replaced with a new wharf which complies with the
performance requirements of this Code for the design of a new wharf to satisfy wharf
strengthening requirements.
f. The overall seismic capacity of existing wharf shall not be reduced by the repairs or
replaced portions.
g. Wharf components also include embankments and dike.
2.4 NONSTRUCTURAL REPAIRS
a. For all Damage Ratios determined according to Section 2.3.a nonstructural repairs that do
not adversely affect any structural member or any part of the existing wharf may be
repaired with the same materials of which the wharf was constructed.
b. The overall seismic capacity of existing wharf shall not be reduced by the nonstructural
repairs.
______________________________________________________________________________
END OF THE CODE
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