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Seismic Design for Petrochemical Facilities As Per NBCC 2005 Dongxiao Wu P. Eng.

2010-05-25 Rev 1.2 Page 1 of 74

TABLE OF CONTENTS

1.0 SCOPE AND APPLICATION ........................................................................................................................................... 2

2.0 GENERAL........................................................................................................................................................................ 2

2.1 Spectral Acceleration Sa(T) and S(T) ........................................................................................................................... 2

2.2 Methods to Determine Site Class................................................................................................................................. 2

2.3 Determine If Seismic Design Is Required for Project ................................................................................................... 2

3.0 METHOD OF ANALYSIS ................................................................................................................................................. 3

4.0 DUCTILTY AND OVERSTRENGTH FACTOR................................................................................................................. 5

5.0 STRUCTURE CLASSIFICATION..................................................................................................................................... 6

Case 01 Building Structures............................................................................................................................................... 8

Case 02 Nonbuilding Structures Similar to Building........................................................................................................... 9

Case 03 Self Supported Vertical Vessel .......................................................................................................................... 10

Case 04 Braced Leg-Supported Ver Vessel..................................................................................................................... 11

Case 05 Self Supported Horizontal Vessel ..................................................................................................................... 12

Case 07 Nonbuilding Structure (Less Than 25% Comb Wt) Supported by Other Structure............................................. 14

Case 08 & 09 Nonbuilding Structure (More Than 25% Comb Wt) Supported by Other Structure.................................... 15

6.0 DESIGN EXAMPLES ..................................................................................................................................................... 17

Design Example 01: Nonbuilding Structure Similar to Building - Exchanger Structure .................................................... 17

Design Example 02: Skirt-Supported Vertical Vessel....................................................................................................... 35

Design Example 03: Braced Leg -Supported Vertical Vessel........................................................................................... 41

Design Example 04: Self-Supported Horizontal Vessel ................................................................................................... 50

Design Example 05: Building Structure............................................................................................................................ 58

Design Example 06: Nonbuilding Structure (> 25% Comb Wt) Supported by Other Structure......................................... 66


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1.0 SCOPE AND APPLICATION

This guideline is intended to be used as supplementary document to NBCC2005 for the seismic design of petrochemical

facilities in Canada, with particular focus on Northern Alberta Fort McMurray area.

This document only covers Equivalent Static Force Procedure (ESFP), which is the easiest and most applicable way to

implement seismic design in low seismic zone like Fort McMurray area.

There is no provision on seismic design of Nonbuilding Structure in NBCC2005. ASCE 7-05 Chapter 15 Seismic Design

Requirements for Nonbuilding Structures is referenced for Nonbuilding Structure seismic design in Canadian location. When

ASCE 7-05 is referenced, NBCC2005 version of ground motion parameters is used to interpret the ASCE 7-05 formula. This

is what NBCC2005 recommends in Commentary J page J-61, Para. 226.

2.0 GENERAL

2.1 Spectral Acceleration Sa(T) and S(T)

Sa(T)

• 5% Damped Spectral Response Acceleration

• Based on Site Class C as per NBCC Table 4.1.8.4.A

• For most cities in Canada, Sa(T) value can be found in NBCC Appendix C Table C-2

S(T)

• Design Spectral Acceleration

• Modified from Sa(T) by applying Fa and Fv factors relating to Site Class NBCC 4.1.8.4 (6)

• S(T) = Sa(T) when specific project site class is Class C

2.2 Methods to Determine Site Class

Two methods are available to determine Site Class if it’s not provided by Geotechnical consultant

1. Average shear wave velocity Vs NBCC Table 4.1.8.4A

• Preferable way to classify Site Class NBCC 4.1.8.4 (2)

• Shear wave velocity Vs is normally available in soil report under dynamic machine foundation section

• Use Vs = SQRT(G/ ρ) = SQRT(Gg / γ ) to get shear wave velocity if only shear modulus is provided

2. SPT N60, for sand site. Undrained shear strength, su, for clay site NBCC Table 4.1.8.4A

2.3 Determine If Seismic Design Is Required for Project

From NBCC 4.1.8.1 … requirements in this Subsection need not be considered in design if S(0.2), as defined in Sentence

4.1.8.4.(6), is less than or equal to 0.12


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Please note it’s S(0.2)


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From Example01, Moment Frame direction, estimated period = 0.91 s, STAAD computed period = 2.43 s

3. NBCC2005 4.1.8.11 (3)(d) sets the upper limit on using longer computed period, considering that the actual structure

may be stiffer than the model in STAAD. For example, mechanical equipments, pipings, cable trays etc are

conventionally not modeled in STAAD while they may actually contribute to the stiffness of SFRS system.

NBCC2005 focuses mainly on residential/commercial buildings, for industrial facilities there are mostly open structures

and less partition wall cases. In high seismic zone, should there be a demand for reducing seismic force to achieve a an

economical design for industrial structures, engineering judgment is required to identify if this upper limit is applicable,

when the engineer is confident that the computer model can reflect the actual SFRS stiffness and give an accurate

period.

4. Seismic serviceability check NBCC 4.1.8.13

• Storey drift weighs more important than lateral deflection at top of structure NBCC Commentary J Para 195

• NBCC 4.1.8.13 (3) specifies storey drift limit 0.025h for normal buildings. 0.025h is an allowable limit for inelastic

storey drift, which is applicable when seismic force is not reduced by dividing RdxRo factor.

Use RdxRo / IE to scale up the drift for comparison with 0.025h when the drift value is obtained from a model with

seismic load scaled down by IE/( RdxRo).


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4.0 DUCTILTY AND OVERSTRENGTH FACTOR

NBCC Table 4.1.8.9

Ductility-Related Seismic Force Reduction Factor Rd

Overstrength-Related Seismic Force Reduction Factor Ro

In high seismic zone, the total seismic load can be more than 20 times of total wind load.

Refer to attached example 01, exchanger structure, site location: Vancouver

Base shear by seismic =8270 kN, base shear by wind =341 kN 8270/341 = 24.3

It’s almost impractical to design a structure deforming elastically with seismic lateral load 24 times of wind load.

RdxRo factor is used to reduce the seismic forces in recognition of the fact that a ductile structure designed based on the

reduced forces is able to dissipate the earthquake energy through inelastic deformation without collapsing.

Higher Ductility of SFRS for High Seismic Zone

In high seismic zone, higher ductility of SFRS is more desirable.

Refer to attached example 01, exchanger structure, site location: Vancouver

If Ductile SFRS is used, RdxRo =5.0x1.5 for moment frame and RdxRo =4.0x1.5 for eccentrically braced frame, the seismic

force for design can be reduced to 8270 / (4.0x1.5) = 1378 kN , which is more comparable to wind load, 341 kN.

Higher Ductility Causes Rigorous Design Requirements for Connection Detailing

The tradeoff of higher ductility for SFRS, is the steel member and connection design requirements.

CSA S16-09 Clause 27 specifies the requirements for design of members and connections for all steel SFRS with Rd >1.5,

with the exception of Conventional Construction, Rd=1.5 Ro=1.3 in S16-09 27.11

Some direct impacts to structural design, if the SFRS is under Clause 27 coverage

1. Limitation on beam and column size, mainly only Class 1 & 2 section are allowed

2. For energy dissipating elements, not the min yield strength Fy , but the probable yield strength RyFy = 1.1Fy shall be

used, and RyFy shall not be less than 460MPa for HSS or 385MPa for others sections S16-09 27.1.7

3. S16-09 requires that all bracing connections in SFRS be detailed such that they are significantly stronger than the

probable tensile capacity of bracing members. S16-09 27.5.4.2

Brace connection design to meet such high capacity is very difficult, considering probable capacity using RyFy = 1.1Fy,

and for HSS RyFy shall not be less than 460MPa. S16-09 27.1.7

4. The amplification factor U2, to account the P-delta effects for structural element in SFRS, is calculated differently

compared to conventional design S16-09 27.1.8.2

5. Ductile moment resisting connections for seismic application must satisfy more rigorous design and detail requirements.

Moment Connection shall be pre-qualified connections and designed as per CISC publication Moment Connections for

Seismic Applications-2008, which contains design procedure of three types of pre-qualified moment resisting

connections.


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Conventional Construction for Low and Moderate Seismic Zone

From above we can see that, once SFRS is covered by S16-09 Clause 27, the increased complexity of SFRS frame member

sizing, frame analysis, connection design and detailing, steel facbrication and erection is tremendous.

In low and moderate seismic zone, Conventional Construction is an advantageous design option to waive all provisions in

S16-09 Clause 27, except clause 27.11.

In low seismic zone like Fort McMurray, the low ductility of Conventional Construction SFRS will not cause significant

increase to member size, as the seismic load is normally lower or comparable to wind load, even using the lower reduction

factor RdxRo value of Conventional Construction.

Refer to attached example 01, exchanger structure, location: For McMurray

The seismic base shear before applying / (RdxRo) is 823 kN, wind load base shear is 341 kN

With Conventional Construction, design seismic load reduced to 823 / (RdxRo) = 823 /(1.5x1.3) = 422 kN, which is already

close to wind load 341 kN use of higher ductility SFRS is not necessary.

In Fort McMurray, always use Conventional Construction, RdxRo = 1.5x1.3, for all SFRS systems.

5.0 STRUCTURE CLASSIFICATION

Most of petrochemical facilities can be classified as the following categories:

1. Building Structure

2. Nonbuilding Structure Similar to Building

3. Nonbuilding Structure Not Similar to Building

4. Nonbuilding Structure (Less Than 25% Comb Wt) Supported by Other Structure

5. Nonbuilding Structure (More Than 25% Comb Wt) Supported by Other Structure


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Classification of Petrochemical Facilities and Applicable Code Provisions

Classification Structure Type Case No Seismic Force Calc RdxRo Factor Structure Example

Building Structure Case 01 NBCC 4.1.8.11NBCC Table 4.1.8.9 Industrial Building, Pump House

Nonbuilding Structure Similar to Building Case 02

NBCC 4.1.8.11

NBCC Table 4.1.8.9

Piperack, Exchanger Structure, Process Module

Skirt-Supported Ver Vessel Case 03

NBCC 4.1.8.11

ASCE 7-05 Table 15.4-2

Skirt-Supported Ver Vessel on Conc Foundation

Braced Leg-Supported Ver Vessel Case 04

NBCC 4.1.8.11


Braced Leg-Supported Ver Vessel on Conc Foundation

Self-Supported Hor Vessel Case 05

NBCC 4.1.8.11


Self-Supported Hor Vessel on Conc/Steel Pier

Nonbuilding StructureRigid Structure Case 06

ASCE 7-05 15.4.2

No RdRo Value Required

Conc Mounted Pump and Compressor

Overall Structure NBCC 4.1.8.11NBCC Table 4.1.8.9

Equipment Support NBCC 4.1.8.17NBCC Table 4.1.8.17

Rigid Nonbuilding Structure Case 08

NBCC 4.1.8.11

NBCC Table 4.1.8.9

Hor Vessel Mounted on Conc/Steel Structure

Nonrigid Nonbuilding Structure Case 09

NBCC 4.1.8.11

NBCC Table 4.1.8.9

Ver Vessel Mounted on Conc/Steel Structure

Exchanger Structure, Process Module

Nonbuilding Structure (More Than 25% Comb Wt) Supported by Other Structure

Case 07

Nonbuilding Structure Not Similar to Building

Nonbuilding Structure (Less Than 25% Comb Wt) Supported by Other Structure

Seismic provision in NBCC2005 is written predominantly to address residential and commercial building structures. It covers

the seismic requirements for Building Structure (clause 4.1.8.11 and table 4.1.8.9) and Nonstructural Component (clause

4.1.8.17 and table 4.1.8.17), but there is no provision for Nonbuilding Structure.

Nonbuilding Structure includes many popular petrochemical facilities, such as all free-standing vertical vessels, flare stacks,

all horizontal vessels, piperacks, exchanger structures, process/equipment modules etc.

In this guideline, ASCE 7-05 Chapter 15 is referenced for seismic design of Nonbuilding Structure. When ASCE 7-05 is

referenced for seismic design in Canadian location, Canadian version of ground motion parameters in NBCC2005 are used

to interpret formulas in ASCE 7-05. This is exactly what NBCC2005 suggests in its Commentary J page J-61 Para. 226.

Some of the equipments, such as hor vessel, can be treated as either Nonstructural Component or Nonbuilding Structure.

When a hor vessel is supported on a steel structure and it’s weight is less than 25% of the combined weight, it’s a

Nonstructural Component and NBCC2005 4.1.8.17 is used to calculate the base shear, for equipment local support design

only. For the overall structure, NBCC2005 4.1.8.11 is used to calculate the base shear. The hor vessel weight is considered

as part of effective seismic weight in the base shear calculation and seismic force distribution.


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Case 01 Building Structures

Building structure seismic force shall be designed as per NBCC 4.1.8.11, with the weight of nonstructural components

(Process, HVAC equipment and Bridge Crane etc) considered as effective seismic weight for base shear calculation and

base shear distribution along vertical direction.

• 25% of roof snow load shall be counted as effective seismic weight for base shear calculation as per NBCC Commentary

J page J-46 note 168

• All process equipments (piping, tank, vessel, exchanger, pump, crusher etc) content weight under normal operating

condition shall be counted as effective seismic weight for base shear calculation as per NBCC Commentary J page J-46

note 168

• For building with crane, only crane empty weight (bridge+trolley/hoist), excluding lifting weight, shall be counted as

effective seismic weight for base shear calculation as per AISC Design Guide 7: Industrial Buildings--Roofs to Anchor

Rods 2nd Edition 13.6 on page 50

Case 01 Building Structure


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Case 02 Nonbuilding Structures Similar to Building

Nonbuilding Structures Similar to Building seismic force shall be designed as per NBCC 4.1.8.11, with the weight of

nonstructural components (Process, Mechanical equipments etc) considered as effective seismic weight for base shear

calculation and base shear distribution along vertical direction.

• 25% of snow load, if there is any, shall be counted as effective seismic weight for base shear calculation as per NBCC

Commentary J page J-46 note 168

• All process equipments (piping, tank, vessel, exchanger, pump, crusher etc) content weight under normal operating

condition shall be counted as effective seismic weight for base shear calculation as per NBCC Commentary J page J-46

note 168

• All Process, Mechanical equipments supported on a steel/conc structure with its weight less than 25% of the combined

weight, shall be designed as Nonstructural Component and NBCC2005 4.1.8.17, for equipment local support design only.

For the overall structure, NBCC2005 4.1.8.11 is used to calculate the base shear. The equipment weight is considered

as part of effective seismic weight in the base shear calculation and seismic force distribution.

Case 02 Nonbuilding Structures Similar to Building


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Case 03 Self Supported Vertical Vessel

Case 03 Self Supported Vertical Vessel

• Vertical vessel seismic force shall be designed as per NBCC

4.1.8.11, with the seismic force distributed as per NBCC 4.1.8.11 (6)

• The seismic overturn moment to vessel base shall be corrected by

multiplying reduction factor J obtained from NBCC Table 4.1.8.11.

This is due to the fact that the higher mode forces, Ft , make a much

smaller contribution to the storey and base overturn moment.

Period Estimation

From ASCE Seismic Design Guideline Page 4.A-4 Case E

Vessel fundamental period tWD12

DH

1078.7T

2

6a ⎟⎠⎞

⎜⎝⎛=

H – vessel height (ft)

D – vessel diameter (ft)

t – vessel thickness (in)

W – vessel linear weight (lb/ft)

HD

t

H4

= H

2 +

2/3

H

V - F t

Ft

H2


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Case 04 Braced Leg-Supported Ver Vessel

Braced Leg Supported vertical vessel seismic force shall be designed as per NBCC 4.1.8.11, with the seismic force

distributed as per NBCC 4.1.8.11 (6).

• The leg brace is normally Tension Only brace which is designed by vendor.

• The vendor will provide foundation load, including seismic case, for foundation and anchor bolt design. The engineer

shall always carry on the seismic load calculation by his own and verify the vendor provided data.

• The Braced Leg Supported vertical vessel is more flexible compared to Skirt Supported vertical vessel. Engineer can

use STAAD to get the fundamental period. Please note that the Tension Only brace makes the support system more

flexible and will generate longer period.

• Depends on the shape of the vertical vessel, it can be classified as Sphere type or Cylinder type. The PSC vessel below

is Sphere type vessel, the seismic load can be applied at mass center. The Deaerator vessel below is the Cylinder type,

the seismic force can be applied as reverse triangle.

• The seismic overturn moment to vessel base shall be corrected by multiplying reduction factor J obtained from NBCC

Table 4.1.8.11. This is due to the fact that the higher mode forces, Ft , make a much smaller contribution to the storey

and base overturn moment.

Case 04 Braced Leg-Supported Ver Vessel


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Case 05 Self Supported Horizontal Vessel

Case 05 Self-Supported Hor Vessel

Case 06 Concrete Base Mounted Pump and Compressor


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Period Estimation

From ASCE Seismic Design Guideline Page 4.A-6 Case G

Period of Vibration – Generalized One-Mass Structure

When y unit is meter, g=9.8 m/s2

T = 2 π sqrt( y/g ) = 2x3.14 x sqrt( y / 9.8m/s2 ) = 2.006 sqrt( y ) sec

y = static deflection of mass resulting from a lateral load applied at the mass equal to its own weight

g = acceleration due to gravity 9.8 m/s2

When y unit is inch

T = 2.006 x sqrt ( yx25.4/1000 ) = 0.32 sqrt( y ) sec

This formula is used to estimate horizontal vessel fundamental period, in both transverse and longitudinal direction.

Case 06 Concrete Base Mounted Pump and Compressor

Nonbuilding structure is not covered in NBCC2005, ASCE 7-05 15.4.2 Rigid Nonbuilding Structures is referenced.

For Concrete Base Mounted Pump and Compressor, the pump and compressor is more like a rigid block and their own

fundamental period is normally less than 0.06s. As defined by ASCE 7-05 15.4.2, nonbuilding structures that have a

fundamental period Ta < 0.06s is classified as Rigid Nonbuilding Structure. The base shear shall be

V = 0.3 S(0.2) W IE ASCE7-05 Eq 15.4-5

This is roughly corresponding to RdxRo =3 where

S(Ta =0.06) = S(0.2) RdxRo =3

V =S(Ta) W IE / (RdxRo) = 0.33 S(0.2) W IE


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Case 07 Nonbuilding Structure (Less Than 25% Comb Wt) Supported by Other Structure

Nonbuilding structures weight is less than 25% of combined (nonbuilding structures+supporting structure) weight

ASCE 15.3.1

• For Local Structural Support Design

Nonbuilding structures seismic force shall be designed as Nonstructural Component as per NBCC 4.1.8.17

• For Supporting Structure Design

Supporting structure seismic force shall be designed as Building Structures or Nonbuilding Structures Similar to Building

as per NBCC 4.1.8.11, with the weight of nonbuilding structure considered as effective seismic weight for base shear

calculation and base shear distribution along vertical direction.

Case 07 Nonbuilding Structure (Less Than 25% Comb Wt) Supported by Other Structure


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Case 08 & 09 Nonbuilding Structure (More Than 25% Comb Wt) Supported by Other Structure

Nonbuilding structures weight is greater than 25% of combined (nonbuilding structures+ supporting structure) weight

ASCE 15.3.2

Case 08 Nonbuilding Structure (More Than 25% Comb Wt) Supported by Other Structure Rigid Nonbuilding Sructures

Nonbuilding structures that have a foundamental period less than 0.06s are considered as Rigid Nonbuilding Structures

ASCE 15.3.2-1

• Nonbuilding structure shall be considered as a rigid element with appropriate distribution of its effective seismic weight

• RdxRo value of combined system is permitted to be taken as the supporting structure’s RdxRo value

• Supporting structure seismic force shall be designed as Building Structures or Nonbuilding Structures Similar to Building

as per NBCC 4.1.8.11

Case 08 Nonbuilding Structure (More Than 25% Comb Wt) Supported by Other Structure

Rigid Nonbuilding Structures


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Nonrigid Nonbuilding Sructures

Nonbuilding structures that have a fundamental period greater than 0.06s are considered as Nonigid Nonbuilding Structures

ASCE 15.3.2-2

• Nonbuilding structure and supporting structure shall be modeled together in a combined model with appropriate stiffness

and effective seismic weight distribution

• RdxRo value of combined system shall be taken as the lesser RdxRo value of the nonbuilding structure or the supporting

structure

• The combined structure seismic force shall be designed as Nonbuilding Structures Similar to Building as per NBCC

4.1.8.11


Nonrigid Nonbuilding Sructures


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6.0 DESIGN EXAMPLES

Design Example 01: Nonbuilding Structure Similar to Building - Exchanger Structure Structure Classification: Case 02 & Case 07

Calculate the seismic force for an exchanger structure supporting stacked heat exchangers as shown on next page.

Frames along GL1,2,3 are moment frame. Frames along GLA, C are braced frame. Frame along GLB is unbraced.

Single exchanger shell operating weight 500 kN, each floor equipment effective seismic weight = 4 x 500 = 2000 kN.

Assume each floor has 20m long 20” dia pipes to be counted for effective seismic weight.

Structure importance category = High as the exchanger contains flamable hydrocarbon content.

Calculate seismic force for the following scenarios:

1. Site in Fort McMurray, Site D, Use SFRS RdxRo of Conventional Construction (CC)

Use Equivalent Static Force Procedure

• Seismic force calc for overall structure steel design

• Seismic force calc for local structure steel support design (exchanger support)

• Compare wind and seismic force, with the RdxRo value of Conventional Construction and Moderately Ductility

2. Site in Vancouver, Site D, Use SFRS RdxRo of Ductile (D) and Moderately Ductility (MD)

Use Equivalent Static Force Procedure

From STAAD output, braced frame in N-S direction Ta=0.66s, moment frame in E-W direction Ta=2.43s


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Example 01 Exchanger Structure


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Wind Load Calc for Overall Structure

To simplify the calc and for comparison purpose only, use the wind load on enclosed structure for a quick check

Wind load pressure 1/50 yr q=0.35 kPa, Cf=1.3, Ce=1.10, Cg=2.0, Iw=1.15

Wind load base shear = Iw x Cf x q x Cg x Ce x A =1.15 x 1.3 x 0.35 x 2.0 x 1.1 x 12.6 x 23.5 = 341 kN

Seismic Base Shear for Overall Structure Design

Location: Fort McMurray Location: Fort McMurray Site Class: Site D

Base Shear Ve

before Ve / (RdxRo)

Base Shear SFRS CC

Ve / (1.5x1.3)

Base Shear SFRS MD

Ve / (3.0x1.3) SFRS

kN kN kN

Moment Frame 328 168 84

Braced Frame 823 422 211

From above seismic base shear calc, we can find that, in low seismic zone such as Fort McMurray area, using Conventiona

Construction (CC) is good enough to bring the lateral seismic force down to a magnitude comparable to wind load, 341 kN.

From CSA S16-09 clause 27.11.1 Conventional construction Rd=1.5 , Ro=1.3

… the requirement of clauses 27.1 to 27.10 and 27.12 shall not apply to these systems.

In low or moderate seismic zone, using a higher RdxRo modification factor is not necessary as it will trade the convenience of

non-seismic connection design for nothing. With the use of response reduction factor RdxRo under Conventional

Construction, the seismic load is already comparable to wind load, and in many cases, seismic load is actually lower than

wind load.

NOTES

It’s incorrect to conceive that in Fort McMurray area the wind load will govern structural design and the seismic load is

neglegible compared to wind load. In this case the seismic load for braced frame, 422 kN, is bigger than the wind load,

341 kN. One may argue that the wind load still gorvern when it goes to the load combination considering wind load factor of

1.4, and seismic load factor of 1.0, but actually in many cases the seismic load will gorven in the design of petrochemical

structures in Fort McMurray area.


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Location: Vancouver

Location: Vancouver Site Class: Site D

Base Shear Ve

before Ve / (RdxRo)

Base Shear SFRS CC

Ve / (1.5x1.3)

Base Shear SFRS MD

Ve / (3.0x1.3)

Base Shear SFRS D

Ve / (4.0x1.5) SFRS

kN kN kN kN

Moment Frame 4185 2146 1073 698

Braced Frame 8270 4241 2121 1378

From above seismic base shear calc, we can find that, in high seismic zone such as Vancouver, using higher modification

factor of RdxRo is absolutely necessary, otherwise the huge seismic lateral load, 8270 / 341 = 24 times of wind load in this

case, will create an impractical structural design.


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LOAD DEVELOPMENT

LOAD DATA INPUT

Structure importance category

Wind Load Data

Wind pressure q 1/50 q = 0.35 [kPa]

Snow Load Data Fort McMurray

Ground snow load 1/50 Ss = 1.50 [kPa] 1.40

Rain load 1/50 Sr = 0.10 [kPa] 0.10

Seismic Data

Site location Avg. soil shear wave Vs = 232 [m/s]

Load Data

Grating+secondary beams area wt. = 1.00 [kPa]

Handrail linear wt. = 0.30 [kN/m]

Ladder with cage linear wt. = 0.50 [kN/m]

Stair+handrail linear wt. = 1.50 [kN/m]

Steel Frame Period

If there is no STAAD output, key in 0 as value for periods below

STAAD output Trans. direction moment frame period TT = 2.43 [s]

STAAD output Long. direction braced frame period TL = 0.66 [s]

Structure Plan Summary

Plan Description Elevation wi (kN) ∆ h (m) Status hi (m)

U/S column base EL.100 EL0 = 100.000 [m]

Plan TOS EL.101 EL1 = 101.000 [m] 2400.7 1.000 Active 1.000

Plan TOS EL.108.5 EL2 = 108.500 [m] 2518.9 7.500 Active 8.500

Plan TOS EL.116 EL3 = 116.000 [m] 2518.9 7.500 Active 16.000

Plan TOS EL.123.5 EL4 = 123.500 [m] 2518.9 7.500 Active 23.500

Plan TOS EL.0 EL5 = 0.000 [m] 0.0 0.000 Inactive 0.000






High

Fort McMurray


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Plan at TOS EL101 Active

Steel Frame Self Weight

Floor beam size 01 W_310 W310x107 1.070 [kN/m]

Size 01 beam length = 75.600 [m] beam wt. = 80.9 [kN]



Column size W_310 W310x202 2.020 [kN/m]

Column number = 9 Column wt. = 18.2 [kN]

Ver. brace size W_310 W150x30 0.300 [kN/m]

Ver. bracing length = 20.000 [m] Ver. bracing wt. = 6.0 [kN]

Hor. brace size WT WT125x22.5 0.225 [kN/m]

Hor. bracing length = 71.200 [m] Hor. bracing wt. = 16.0 [kN]

Grating area = 159.000 [m2] Grating+beams wt. = 159.0 [kN] 1.00 [kPa]

HR total length run in Long. direction = 25.200 [m] Handrail Long. wt. = 7.6 [kN] 0.30 [kN/m]

HR total length run in Trans. direction = 25.200 [m] Handrail Trans. wt. = 7.6 [kN] 0.30 [kN/m]

Ladder ver. tributary length = 15.000 [m] Ladder wt. = 7.5 [kN] 0.50 [kN/m]

Stair/Linkway tributary length = 0.000 [m] Stair/Linkway wt. = 0.0 [kN] 1.50 [kN/m]

Piping Operating Weight

1.2 kPa pipe blanket load width = 0.000 [m]

length = 0.000 [m]

Pipe operating wt. = 0.0 [kN]

Dia Class Insul.

1) Pipe Dia. 20" 20 XS 75mm Oper Upo= 3.551 [kN/m]

Total 20" dia pipe length = 20.000 [m] Pipe operating wt. = 71.0 [kN]

Dia Class Insul.



Equipment Weight

Equipment operating weight = 2000.0 [kN]

Cable Tray Weight

Cable tray width = 0.000 [m]

Cable tray total length = 0.000 [m]

Apply uniformly blanket load 1.0 kPa for cable tray Cable tray wt. = 0.0 [kN]

Total Operating Weight TOS EL101 w1 = 2400.7 [kN]


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Plan at TOS EL108.5 Active

Steel Frame Self Weight





Column size W_310 W310x202 2.020 [kN/m]

Column number = 9 Column wt. = 136.3 [kN]

Ver. brace size W_310 W150x30 0.300 [kN/m]

Ver. bracing length = 20.000 [m] Ver. bracing wt. = 6.0 [kN]

Hor. brace size WT WT125x22.5 0.225 [kN/m]

Hor. bracing length = 71.200 [m] Hor. bracing wt. = 16.0 [kN]

Grating area = 159.000 [m2] Grating+beams wt. = 159.0 [kN] 1.00 [kPa]

HR total length run in Long. direction = 25.200 [m] Handrail Long. wt. = 7.6 [kN] 0.30 [kN/m]

HR total length run in Trans. direction = 25.200 [m] Handrail Trans. wt. = 7.6 [kN] 0.30 [kN/m]

Ladder ver. tributary length = 15.000 [m] Ladder wt. = 7.5 [kN] 0.50 [kN/m]

Stair/Linkway tributary length = 0.000 [m] Stair/Linkway wt. = 0.0 [kN] 1.50 [kN/m]

Piping Operating Weight

1.2 kPa pipe blanket load width = 0.000 [m]

length = 0.000 [m]

Pipe operating wt. = 0.0 [kN]

Dia Class Insul.



Dia Class Insul.



Equipment Weight

Equipment operating weight = 2000.0 [kN]

Cable Tray Weight

Cable tray width = 0.000 [m]

Cable tray total length = 0.000 [m]

Apply uniformly blanket load 1.0 kPa for cable tray Cable tray wt. = 0.0 [kN]

Total Operating Weight TOS EL108.5 w1 = 2518.9 [kN]


2010-05-25 Rev 1.2 Page 24 of 74

1 of 3

SEISMIC LOAD CALC - FORT MCMURRAY

Seismic load calc based on Code Abbreviation

NBCC 2005 Division B 4.1.8 NBC05

NBCC 2005 Commentary J NBC05 Comment J

CSA S16-09 Limit States Design of Steel Structures CSA S16-09

Site location Fort McMurray Code Reference

Spectral Response Acceleration

Sa(0.2) = 0.120 Sa(0.5) = 0.056

Sa(1.0) = 0.023 Sa(2.0) = 0.006

Sa(0.2) / Sa(2.0) = 20.0

Site Classification NBC05

Avg soil shear wave velocity Vs = 232 [m/s] Site D Table 4.1.8.4.A

Site Properties

Fa = 1.300 Table 4.1.8.4.B

Fv = 1.400 Table 4.1.8.4.C

Design Spectral Acceleration

S(T=0.2s) = 0.156 4.1.8.1 (1)

S(T=0.5s) = 0.078 4.1.8.4 (6)

S(T=1.0s) = 0.032

S(T=2.0s) = 0.008

S(T=4.0s) = 0.004

Structure Importance Category High

Importance factor IE = 1.30 For importance category High structure Table 4.1.8.5

Ductility and Overstrength Factor

Conventional construction Rd = 1.5 Ro = 1.3 Table 4.1.8.9

Use conventional construction for both Trans. moment frame and Long. braced frame, so that

connection can be designed with non-seismic provision of CSA S16-09 CSA S16-09

Other provisions of Clause 27 in CSA S16-01 do not apply to conventional construction 27.11.1

>0.12 seismic shall be considered


2010-05-25 Rev 1.2 Page 25 of 74

2 of 3


Plan Description Elevation wi hi (kNm) hi (m) Status


Plan TOS EL.101 EL1 = 101.000 [m] 2400.7 1.000 Active

Plan TOS EL.108.5 EL2 = 108.500 [m] 21410.3 8.500 Active



Plan TOS EL.0 EL5 = 0.000 [m] 0.0 0.000 Inactive






Sum 123306.0

Code Reference

TRANSVERSE FRAMES SEISMIC LOAD NBC 05

Seismic resistance system Steel Moment Frame

Structure height hn = 23.5 [m]

Period estimated TE = 0.085 (hn) ^0.75 = 0.91 [s] 4.1.8.11 3) a)


Period used for design Ta = min (1.5TE , TT ) when TT > TE = 1.36 [s] 4.1.8.11 3) d)

Higher mode factor Mv Moment Frame Mv = 1.07 Table 4.1.8.11

S(Ta=1.36s) = 0.024 4.1.8.4 (6)

Seismic Base Shear VTa = S(Ta) Mv IE ΣWi / (Rd Ro) = 168.1 [kN] 4.1.8.11(2)Vmin = S(2.0) Mv IE ΣWi / (Rd Ro) = 59.8 [kN]Vmax = 2/3 S(0.2) IE ΣWi / (Rd Ro) = 690.4 [kN]

V = V ≥ Vmin and V ≤ Vmax = 168.1 [kN]

Seismic force acting at top Ft = = 16.0 [kN] 4.1.8.11(6)

Seismic force for distribution V-Ft = 152.0 [kN]

Seismic Load Distribution

The load below are seimic load at each level, applys to to all frames in transverse direction.

F1 = 3.0 [kN] F6 = 0.0 [kN] 4.1.8.11(6)

F2 = 26.4 [kN] F7 = 0.0 [kN]

F3 = 49.7 [kN] F8 = 0.0 [kN]

F4 = 89.0 [kN] F9 = 0.0 [kN]

F5 = 0.0 [kN] F10 = 0.0 [kN]

2518.9

0.0

wi (kN)

2400.7

2518.9

0.0

9957.3

If Ta0.7 then Ft = 0.07TaV


2010-05-25 Rev 1.2 Page 26 of 74

3 of 3

LONGITUDINAL FRAMES SEISMIC LOAD Code Reference

Seismic resistance system Steel Braced Frame NBC 05


Period estimated TE = 0.025 hn = 0.59 [s] 4.1.8.11 3) b)

STAAD output Trans. direction moment frame period TL = 0.66 [s]

Period used for design Ta = min (2TE , TL ) when TL > TE = 0.66 [s] 4.1.8.11 3) d)

Higher mode factor Mv Braced Frame Mv = 1.00 Table 4.1.8.11

S(Ta=0.66s) = 0.064 4.1.8.4 (6)






The load below are seimic load at each level, applys to to all frames in longitudinal direction.

F1 = 8.2 [kN] F6 = 0.0 [kN] 4.1.8.11(6)

F2 = 73.3 [kN] F7 = 0.0 [kN]

F3 = 138.0 [kN] F8 = 0.0 [kN]

F4 = 202.7 [kN] F9 = 0.0 [kN]

F5 = 0.0 [kN] F10 = 0.0 [kN]



2010-05-25 Rev 1.2 Page 27 of 74

1 of 3

SEISMIC LOAD CALC - VANCOUVER




CSA S16-09 Limit States Design of Steel Structures CSA S16-09

Site location Vancouver Code Reference


Sa(0.2) = 0.950 Sa(0.5) = 0.650

Sa(1.0) = 0.340 Sa(2.0) = 0.170

Sa(0.2) / Sa(2.0) = 5.6

Site Classification NBC05


Site Properties

Fa = 1.100 Table 4.1.8.4.B

Fv = 1.160 Table 4.1.8.4.C


S(T=0.2s) = 1.045 4.1.8.1 (1)

S(T=0.5s) = 0.754 4.1.8.4 (6)

S(T=1.0s) = 0.394

S(T=2.0s) = 0.197

S(T=4.0s) = 0.099

Structure Importance Category High

Importance factor IE = 1.30 For importance category High structure Table 4.1.8.5

Ductility and Overstrength Factor

Conventional construction Rd = 1.5 Ro = 1.3 Table 4.1.8.9

Use conventional construction for both Trans. moment frame and Long. braced frame, so that

connection can be designed with non-seismic provision of CSA S16-09 CSA S16-09

Other provisions of Clause 27 in CSA S16-01 do not apply to conventional construction 27.11.1



2010-05-25 Rev 1.2 Page 28 of 74

2 of 3


Plan Description Elevation wi hi (kNm) hi (m) Status












Sum 123306.0

Code Reference

TRANSVERSE FRAMES SEISMIC LOAD NBC 05

Seismic resistance system Steel Moment Frame


Period estimated TE = 0.085 (hn) ^0.75 = 0.91 [s] 4.1.8.11 3) a)


Period used for design Ta = min (1.5TE , TT ) when TT > TE = 1.36 [s] 4.1.8.11 3) d)

Higher mode factor Mv Moment Frame Mv = 1.00 Table 4.1.8.11

S(Ta=1.36s) = 0.323 4.1.8.4 (6)






The load below are seimic load at each level, applys to to all frames in transverse direction.

F1 = 37.8 [kN] F6 = 0.0 [kN] 4.1.8.11(6)

F2 = 337.1 [kN] F7 = 0.0 [kN]

F3 = 634.5 [kN] F8 = 0.0 [kN]

F4 = 1136.3 [kN] F9 = 0.0 [kN]

F5 = 0.0 [kN] F10 = 0.0 [kN]

2518.9

0.0

wi (kN)

2400.7

2518.9

0.0

9957.3



2010-05-25 Rev 1.2 Page 29 of 74

3 of 3

LONGITUDINAL FRAMES SEISMIC LOAD Code Reference

Seismic resistance system Steel Braced Frame NBC 05


Period estimated TE = 0.025 hn = 0.59 [s] 4.1.8.11 3) b)

STAAD output Trans. direction moment frame period TL = 0.66 [s]

Period used for design Ta = min (2TE , TL ) when TL > TE = 0.66 [s] 4.1.8.11 3) d)

Higher mode factor Mv Braced Frame Mv = 1.00 Table 4.1.8.11

S(Ta=0.66s) = 0.639 4.1.8.4 (6)






The load below are seimic load at each level, applys to to all frames in longitudinal direction.

F1 = 82.6 [kN] F6 = 0.0 [kN] 4.1.8.11(6)

F2 = 736.4 [kN] F7 = 0.0 [kN]

F3 = 1386.2 [kN] F8 = 0.0 [kN]

F4 = 2036.1 [kN] F9 = 0.0 [kN]

F5 = 0.0 [kN] F10 = 0.0 [kN]



2010-05-25 Rev 1.2 Page 30 of 74

Seismic Base Shear for Exchanger Support Design

In this part the equipment is taken as a Nonstructural Component and its seismic force is calculated as per NBCC 4.1.8.17.

This seismic force is used for the design of local equipment support only (steel support for exchangers).

The exchangers sitting on top of structure (EL23.500) get the biggest seismic response as the acceleration increases with

the height of structure. This effect is caputured by the height factor, newly introduced in NBCC2005, Ax = 1 + 2hx / hn

For equipments at foundation level Ax = 1.0, and Ax = 3.0 for equipments sitting at roof level.

Location: Fort McMurray Site Class: Site D

Transverse Direction Longitudinal Direction Lateral Load Type

kN kN

Wind 18 4

Seismic 122 243

From above we find that, for local equipment support design, the seismic load is much bigger than the wind load if the

equipment is located on a higher elevation above grade. This is mainly due to the dynamic amplifying effect (Ar =2.5) for big

mass sitting on a flexible supporting structure.

NOTES


negligible compared to wind load. In this case the seismic load can be 243/4 = 61 times bigger than the wind load.


2010-05-25 Rev 1.2 Page 31 of 74

1 of 4

SEISMIC LOAD CALC - EXCHANGER SUPPORT

Exchanger support design based on Code Abbreviation


ASCE Wind Loads and Anchor Bolt Design for Petrochemical Facilities ASCE Wind Loads

PIP STE03360 Heat Exchanger and Horizontal Vessel Foundation Design Guide-2007 PIP STE03360

INPUT

Exchanger Data

Shell OD D = 1470 [mm] Insul. Thickness = 38 [mm]

Overall OD OD = 1546 [mm] H1 = 1200 [mm]

Exchanger length L = 11092 [mm] H2 = 975 [mm]

Saddle distance S = 4900 [mm] H3 = 2246 [mm]

Steel support width W = 1400 [mm] H4 = 0 [mm]

L1 = 1200 [mm]

Single Shell Weight Estimated Wei

Empty weight We = 350 [kN] 300

Operating weight Wo = 500 [kN] 489

Hydro test weight Wt = 500 [kN] 489

Bundle weight Wbp = 144 [kN] 226

Number of stacked shells n = 2

Wind Data



2010-05-25 Rev 1.2 Page 32 of 74

2 of 4

Seismic Data Code Reference

Site location NBC 05

Site Classification



Importance factor seismic load IE = 1.30 For importance category High structure Table 4.1.8.5

Importance factor wind load Iw = 1.15 For importance category High structure Table 4.1.7.1

Exchanger contains toxic or flamable liquid Yes Cp = 1.5 Table 4.1.8.17

Support floor base height hx = 23.500 [m]

Total structure height hn = 23.500 [m]

Steel Support Data

Steel support beam size W250x73

Steel support column size W250x73

Steel support bracing size DAngle_LLV 2L102x76x7.9LLBB

Fort McMurray

High


2010-05-25 Rev 1.2 Page 33 of 74

3 of 4

GRAVITY LOAD Code Reference

Stacked Shells Total Weight Add 20% of single shell wei to account for attached misc. piping & insulation wei

(n+0.2)xWe = 770 [kN]

(n+0.2)xWo = 1100 [kN]

(n+0.2)xWt = 1100 [kN] PIP STE03360

Gravity load distributed 60% at channel end, 40% at shell end. Use 60% for design of both ends. 4.2.1.3

Empty case De = 462 [kN]

Operating case Do = 660 [kN]

Hydro test case Dt = 660 [kN]

Trans. Moment from Piping Eccentricity PIP STE03360

Ecc = 0.5OD + 1.5ft e = 1230 [mm] 4.2.1.2 d.

Apply 0.6 x 10% of single shell weight with eccentricity e as trans. moment for both ends

Empty case MTe = 26 [kNm]

Operating case MTo = 37 [kNm]

Hydro test case MTt = 37 [kNm]

WIND LOAD

Transverse Wind NBC05 Comment I

Cg = 2.00 L/D = 7.2

Cf = 0.80 Rough surface Fig. I-24

Exchanger height above grade H = EL + (H1 + H2 + H3) = 27.9 [m]

Ce = 1.23 NBC05 4.1.7.1 (5)

Add 1.5ft (0.46m) to OD to account for piping attached to exchanger ASCE Wind Loads

A = L x (D + 0.46) = 22.2 [m2] Section 4.3.2.2

NBC05 Comment I

Wind force on single shell FT1 = Iw x Cf x q x Cg x Ce x A = 17.6 [kN] Fig. I-24

Trans. Wind on Steel Support

Trans. base shear FT = FT1 x n (shell) / 2 (end) = 17.6 [kN]

Trans. OTM to support base MTW = [ FT1x(H2+H3+H4)+FT1x(H2+H3) + = 36.9 [kNm]

FT1xH2 ] /2 (end)

Longitudinal Wind ASCE Wind Loads

Cf = 1.20 Assume flat head to be conservative Section 4.3.2.4

Add 1.5ft (0.46m) to OD to account for piping attached to exchanger ASCE Wind Loads

A = π (D + 0.46)2 / 4 = 3.2 [m2] Section 4.3.2.2

Wind force on single shell FL1 = Iw x Cf x q x Cg x Ce x A = 3.7 [kN]

Long. Wind on Steel Support

Long. base shear FL = FL1 x n (shell) / 2 (end) = 3.7 [kN]

Couple on supp caused by wind Nw = [ FL1(H2+H3+H4) + FL1(H2+H3) + = 3.2 [kN]

FL1H2 ] / S


2010-05-25 Rev 1.2 Page 34 of 74

4 of 4

Code Reference

BUNDLE PULL LOAD PIP STC01015-2007

Min. bundle pull force Vminbp = min( 2kips, We ) = 9 [kN] 4.1.8.1

Bundle pull force Vbp = max( 1.5xWbp, Vminbp ) = 216 [kN]

Vbp applied at top bundle center Hbp = H2 + H3 = 3221 [mm]

Apply 100% of bundle pull load to fixed end

Long. Fixed end base shear Vbp = = 216.0 [kN]

Couple on supp caused by BP Nbp = Vbp x Hbp / S = 142.0 [kN]

THERMAL LOAD

Long. Thermal Force on Steel Support

Long. base shear Ff = max(Do, Dt) x 0.1 = 66.0 [kN]

SEISMIC LOAD

Design exchangers seismic load as Nonstructural Component as per NBC05 4.1.8.17 NBC05

Exchanger contains toxic or flamable liquid Yes

Component risk factor Cp = 1.5 Table 4.1.8.17

Exchanger supported flexibly by steel frame with T > 0.06s Category 12

Force amplification factor Ar = 2.5 Table 4.1.8.17

Response modification factor Rp = 2.5

Importance Factor IE = 1.3


Sa(0.2) = 0.120 Sa(0.5) = 0.056

Sa(1.0) = 0.023 Sa(2.0) = 0.006

NBC 05

Site Properties Fa = 1.300 Table 4.1.8.4.B

Height factor Ax = (1 + 2hx / hn) = 3.0 4.1.8.17

Sp = CpArAx / Rp = 4.5

Sp = 0.7


2010-05-25 Rev 1.2 Page 35 of 74

Design Example 02: Skirt-Supported Vertical Vessel

Structure Classification: Case 03

Calculate the seismic force for a skirt-supported vertical vessel

Vessel diameter = 7.189 m

Vessel height = 12.400 m

Vessel shell thickness = 0.25 in

Vessel empty weight = 221 kN

Vessel operating weight = 3793 kN

Vessel hydrotest weight = 5055 kN

Site location : Fort McMurray

Site class : Class D

Structure importance category : Normal

NOTES


negligible compared to wind load. In this case

seismic base shear is 131.5 kN vs wind base shear 71.9 kN

seismic overturn moment is 1087.0 kNm vs wind overturn moment 499.9 kNm

In this case, the overturn moment caused by seismic is 2 times of the overturn moment caused by wind. This is mainly due

to the reverse triangle distribution of seismic load.


2010-05-25 Rev 1.2 Page 36 of 74

DESCRIPTION 1 of 5

Vertical vessel foundation design based on Code Abbreviation



PIP STE03350 Vertical Vessel Foundation Design Guide-2007 PIP STE03350

PIP STE05121 Anchor Bolt Design Guide-2006 PIP STE05121

INPUT

Vessel Data


Vessel diameter D = 7.189 [m]

Vessel height H = 12.400 [m]

Vessel content height H1 = 12.400 [m]

Mat thickness H2 = 0.650 [m]

Vessel shell thickness t = 0.250 [in]

Vessel Weight Estimated

Vessel surface area = 361.2 [m2]

Vessel volume = 503.3 [m3]

Vessel content weight = 5033 [kN] water 10kN/m2

Vessel empty weight = 867 [kN] shell 50lb/ft2

Vessel operating weight = 5900 [kN]

Vessel Weight from Vendor Estimated Wei

Vessel empty weight = 221 [kN] 867

Vessel operating weight = 3793 [kN] 5900

Vessel hydro test weight = 5055 [kN] 5900

Vessel Weight for Design

Vessel empty weight We = 265 [kN] Increase empty wei 20% to account for insulation/piping wei

Vessel operating weight Wo = 4016 [kN] Increase content wei 5% to account for pipe content wei

Vessel hydro test weight Wh = 5341 [kN] These increase doesn't apply to uplift load comb cases

Overturn Moment Due to Piping Eccentricity

Take 10% of vessel empty weight as eccentric piping/nozzle weight

Pipe eccentricity= D/2 + 0.5m = 4.095 [m]

Piping/nozzle eccentric weight = 22.1 [kN]

Overturn Moment by Pipe Ecc Mpip = 90.5 [kNm]

Vessel top platform width Wp = 1.200 [m]

Vessel top platform length Lp = 8.000 [m]


Top platform live load LL = 4.80 [kPa]

Top platform dead load DL = 2.00 [kPa] including framing and grating

Snow load SL = 1.50 [kPa]

Normal

H

3H

= H

2+

1H

pL

0.5

H

1F

2F

2


2010-05-25 Rev 1.2 Page 37 of 74

2 of 5

WIND LOAD

Wind load calc based on Code Abbreviation


NBCC 2005 Commentary I NBC05 Comment I


ASME STS-1-2006 Steel Stacks ASME Steel Stacks

Code Reference

Structure importance category Normal

Importance factor Iw = 1.00 For importance category Normal structure NBC05 Table 4.1.7.1





Ce = 1.04 NBC05 4.1.7.1 (5)

Cg = 2.00 NBC05 4.1.7.1 (6)

Dxsqrt (qCe) = 4.346 >0.167 H/D = 1.7 NBC05 Comment I


Vortex Shedding Check NBC05 Comment I

Strouhal Number S = 0.20 For large-diameter structures page I-33

Vessel 1st mode frequency fn=1/Ta = 8.87 [Hz] Get period Ta from seismic analysis

Critical mean wind speed at top VHC = fn D / S = 318.8 [m/s] page I-33 (16)

when resonance occurs

Dynamic Exposure Factor CeH = 1.06 Exposure A page I-24 (7)

Wind speed at 10m height V = 39.2 sqrt(q) = 23.2 [m/s] page I-29 (14)

Mean wind speed at top VH = V sqrt (CeH) = 23.9 [m/s] page I-29 (13)

ASME Steel Stacks

Vortex shedding can be ignored if VHC > 1.2 VH VHC > 1.2VH clause 5.2.2 (3)

Wind on Attached Piping and Ladder

Use simplified method in ASCE Wind Loads and Anchor Bolt Design for Petrochemical Facilities

ASCE Wind Loads

Add 5ft (1.52m) to vessel diameter to account for ladder & piping attached below top tangent line clause C.4.3.1.2

Wid = D + 1.52 = 8.71 [m]

Add 5ft (1.52m) to vessel height to account for piping attached above top tangent line

Hei = H + 1.52 = 13.92 [m]

A = Wid x Hei = 121.23 [m2]

NBC05 Comment I

Wind on Vessel

Wind force on vessel F1 = Iw x Cf x q x Cg x Ce x A = 63.1 [kN] Fig. I-24

Response of vortex shedding can be ignored


2010-05-25 Rev 1.2 Page 38 of 74

3 of 5

Wind on Top Platform ASCE Wind Loads

Assume platform framing is 10" (254mm) in depth -> framing projected area Ae = 0.25m2/m

Handrail projected area Ae = 0.25m2/m Table 4.1

Cf = 2.0 Section 4.3.2.6

Ce = 1.04 NBC05 4.1.7.1 (5)


Platform framing Ae1 = 0.25 x Lp = 2.0 [m2]

Front and back handrail Ae2 = 0.25 x 2Lp = 4.0 [m2]

Total projected area Ae = Ae1 + Ae2 = 6.0 [m2]

Wind force on platform F2 = Iw x Cf x q x Cg x Ce x A = 8.8 [kN]

Base shear by wind F = F1 + F2 = 71.9 [kN]

Wind OTM to vessel bottom Mw1 = F1 x 0.5H + F2 x H = 499.9 [kNm]

Wind OTM to mat bott surface Mw2 = F1 x (0.5H+H2) + F2 x( H+H2) = 546.6 [kNm]

VESSEL TOP PLATFORM LIVE & SNOW LOAD




Top platform dead load DL = 2.0 [kPa] including framing

Snow load SL = 1.5 [kPa] and grating

Platform dead load = DL x Wp x Lp = 19.2 [kN]

Platform live load = LL x Wp x Lp = 46.1 [kN]

Vessel top snow load = SL x (π D2) / 4 = 60.9 [kN]

Since live load 4.8 kPa always override snow load, take max of live & snow load as live load

Max of platform live load and vessel top accumulated snow load = 60.9 [kN]

H

3H

= H

2+

1H

pL

0.5

H

1F

2F

2


2010-05-25 Rev 1.2 Page 39 of 74

4 of 5

SEISMIC LOAD




ASCE Guidelines for Seismic Evaluation and Design of Petrochemical Facilities 1997 ASCE Seismic Guide

ASCE7-05 Minimum Design Loads for Buildings and Other Structures ASCE7-05

Vessel Data

Vessel Operating Weight Wop = 853 [kips]

Vessel Height H = 40.682 [ft]

Vessel Diameter OD D = 23.586 [ft]

Vessel Shell Thickness t = 0.250 [in]

Vessel Linear Wei W = Wop/H W = 20960 [lb/ft] Code Reference

Vessel Period = 0.113 [sec] ASCE Seismic Guide

Appendix 4.A

Seismic data from NBC05 Div B Appendix C Table C-2

Site location


Sa(0.2) = 0.120 Sa(0.5) = 0.056

Sa(1.0) = 0.023 Sa(2.0) = 0.006

Higher Mode Factor Mv and Overturning Reduction Factor J

Sa(0.2) / Sa(2.0) = 20.0 NBC 05

Mv = 1.00 J = 1.00 Table 4.1.8.11

Site Classification


Structure Importance Category Normal

Fort McMurray

HD

t

H4

= H

2 +

2/3

H

V - F t

Ft

H2

tWD12

DH

1078.7T

2

6a ⎟⎠⎞

⎜⎝⎛=


2010-05-25 Rev 1.2 Page 40 of 74

5 of 5

Code Reference

Site Properties NBC 05

Fa = 1.300 Table 4.1.8.4.B

Fv = 1.400 Table 4.1.8.4.C


S(T=0.2s) = 0.156 4.1.8.1 (1)

S(T=0.5s) = 0.078 4.1.8.4 (6)

S(T=1.0s) = 0.032

S(T=2.0s) = 0.008

S(T=4.0s) = 0.004

S(Ta=0.11s) = 0.156 4.1.8.4 (6)

Importance factor IE = 1.00 For importance category Normal structure Table 4.1.8.5

ASCE7-05

Ductility & Overstrength Factor RdxRo = 3.0 Table 15.4-2

NBC 05

Vessel Operating Weight Wop = 853 [kips] = 3793 [kN]

Seismic Base Shear VTa = S(Ta) Mv IE Wop / (Rd Ro) = 197.2 [kN] 4.1.8.11(2)

Vmin = S(2.0) Mv IE Wop / (Rd Ro) = 10.6 [kN]

Vmax = 2/3 S(0.2) IE Wop / (Rd Ro) = 131.5 [kN]



Seismic force acting at 2/3H V-Ft = 131.5 [kN]

H = 12.400 [m]

H2 = 0.650 [m]

H4 = H2 + 2/3 H = 8.917 [m]

H5 = H2 + H = 13.050 [m]

Base shear by seismic V = 131.5 [kN]

Seismic OTM to vessel bottom Ms1 = [ Ft x H + (V-Ft) x 2/3H ] x J = 1087.0 [kNm]

Seismic OTM to mat bott surface Ms2 = [ Ft x H5 + (V-Ft) x H4 ] x J = 1172.5 [kNm]

If Ta0.7 then Ft = 0.07TaV 0.12 seismic shall be considered

No provision for nonbuilding struc in NBC05 Table 4.1.8.9. Use R=RdxRo=3.0 in ASCE7-05 for nonbuilding struc skirt-supported vertical vessel


2010-05-25 Rev 1.2 Page 41 of 74

Design Example 03: Braced Leg -Supported Vertical Vessel


Calculate the seismic force for a braced-leg supported PSC vessel. The PSC vessel is supported by 10 x OD=1450mm wall

thk =27mm steel column equally spaced at 22.5m diameter circle. The 3D support frame is braced by 25 dia steel tension

only rod. Vessel empty weight = 13810 kN , operating weight = 183710 kN

Site location : Fort McMurray Site class : Class D Structure importance category : Normal

The PSC vessel is a cone shape, diameter varies from 0m to 32m along the 30m vessel height. To simplify the wind load

calculation, assume it’s a dia=16m H=30m cylinder vessel, which gives the same projection area for wind load calc.

Braced-Leg Supported PSC Vessel


2010-05-25 Rev 1.2 Page 42 of 74

Use Master/Slave to define the top support plane as a rigid diaphragm. Use the central node as a master node, the central

node needs not to be physically connecting to the surrounding nodes.

STAAD Model : Rigid Diaphragm and Tension Only Brace


2010-05-25 Rev 1.2 Page 43 of 74

STAAD Model : PSC Vertical Vessel Support

Two approaches are used to get the fundamental period of vessel support

1. Use STAAD CALCULATE RAYLEIGH FREQUENCY command to get Rayleigh frequency

STAAD returns Rayleigh frequency 0.26558 CPS Ta = 1/0.26558 = 3.765 s

2. Apply vessel operating weight as lateral load at mass center, get the hor deflection Δ in inch, Ta = 0.32 sqrt( Δ )

STAAD returns hor deflection Δ = 3522mm = 138.66 in Ta = 0.32 sqrt( Δ ) = 0.32 sqrt( 138.66 ) = 3.768 s

These two approaches are actually the same way of estimating structure period. Here is just a proof that the estimating

formula Ta = 0.32 sqrt( Δ ), which is used in hor vessel case, is good for practical use.

Use Ta = 3.765s to calculate seismic force for PSC vessel.


2010-05-25 Rev 1.2 Page 44 of 74

NOTES





In this case, the overturn moment caused by seismic is 2.0 times of the overturn moment caused by wind. This is mainly due

to

• Ta >0.7s causing Ft >0

• Vessel mass center is located at a higher elevation


2010-05-25 Rev 1.2 Page 45 of 74

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DESCRIPTION

Vertical vessel foundation design based on Code Abbreviation



PIP STE03350 Vertical Vessel Foundation Design Guide-2007 PIP STE03350


INPUT

Vessel Data


Vessel height above pedestal H = 30.000 [m]


Mat Thickness H2 = 1.200 [m]

Pedestal height H3 = 0.650 [m]

Support leg height H4 = 16.500 [m]

Vessel CG height H5 = 26.000 [m]

Vessel leg number Np = 10

Vessel leg circle dia. Dlegc = 22.500 [m]

Leg support brace section area Abr = 491 [mm2]

Vessel type


Support struc period from STAAD Ta = 3.765 [s]

Vessel Weight Estimated

Vessel Surface Area = 1407.4 [m2]

Vessel Volume = 4021.2 [m3]

Vessel Content Weight = 40212 [kN] water 10kN/m2

Vessel Empty Weight = 3378 [kN] shell 50lb/ft2

Vessel Operating Weight = 43590 [kN]

Vessel Weight from Vendor Estimated Wei

Vessel Empty Weight = 13810 [kN] 3378

Vessel Operating Weight = 183710 [kN] 43590

Vessel Hydro Test Weight = 183710 [kN] 43590

Vessel Weight for Design

Vessel Empty Weight We = 16572 [kN] Increase empty wei 20% to account for insulation/piping wei

Vessel Operating Weight Wo = 194967 [kN] Increase content wei 5% to account for pipe content wei

Vessel Hydro Test Weight Wh = 194967 [kN] These increase doesn't apply to uplift load comb cases





Top platform dead load DL = 2.00 [kPa] including framing and grating

Snow load SL = 1.50 [kPa]

Sphere

Normal

2H

3H

1L

4H

5H

CG

D

1H

H

pL


2010-05-25 Rev 1.2 Page 46 of 74

WIND LOAD 2 of 5





ASME STS-1-2006 Steel Stacks ASME Steel Stacks

Vessel diameter D = 16.000 [m] Code Reference





H < 10m Ce0 = 1.00 H=30m ~ 40m Ce3 = 1.32 NBC05 4.1.7.1 (5)

H=10m ~ 20m Ce1 = 1.15 H=40m ~ 50m Ce4 = 1.38

H=20m ~ 30m Ce2 = 1.25 H=50m ~ 60m Ce5 = 1.43

Ce at vessel top Cet = 1.25

Cg = 2.00 NBC05 4.1.7.1 (6)

Dxsqrt (qCet) = 10.565 >0.167 H/D = 1.9 NBC05 Comment I


Structure importance category = Normal


Vortex Shedding Check NBC05 Comment I

Strouhal Number S = 0.20 For large-diameter structures page I-33

Vessel 1st mode frequency fn=1/Ta = 0.27 [Hz] Get period Ta from seismic analysis

Critical mean wind speed at top VHC = fn D / S = 21 [m/s] page I-33 (16)

when resonance occurs

Dynamic Exposure Factor CeH = 1.36 Exposure A page I-24 (7)

Wind speed at 10m height V = 39.2 sqrt(q) = 23.2 [m/s] page I-29 (14)

Mean wind speed at top VH = V sqrt (CeH) = 27.0 [m/s] page I-29 (13)

ASME Steel Stacks

Vortex shedding can be ignored if VHC > 1.2 VH VHC < 1.2VH clause 5.2.2 (3)

Wind on Attached Piping and Ladder

Use simplified method in ASCE Wind Loads and Anchor Bolt Design for Petrochemical Facilities ASCE Wind Loads

Add 5ft (1.52m) to vessel diameter to account for ladder & piping attached below top tangent line clause C.4.3.1.2

Wid = D + 1.52 = 17.52 [m]

Add 5ft (1.52m) to vessel height to account for piping attached above top tangent line.

Hei = H + 1.52 = 31.52 [m]

A = Wid x Hei = 552.23 [m2] NBC05 Comment I

Wind on Vessel F1 = Iw x Cf x q x Cg x Ce x A = 315.1 [kN] Fig. I-24

H < 10m F10 = 87.6 [kN] H=30m ~ 40m F13 = 17.6 [kN]

H=10m ~ 20m F11 = 100.7 [kN] H=40m ~ 50m F14 = 0.0 [kN]

H=20m ~ 30m F12 = 109.2 [kN] H=50m ~ 60m F15 = 0.0 [kN]

Response of vortex shedding shall be considered


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Wind on Top Platform ASCE Wind Loads



Cf = 2.0 Section 4.3.2.6

Ce = 1.25 NBC05 4.1.7.1 (5)


Platform framing Ae1 = 0.25 x Lp = 0.8 [m2]

Front and back handrail Ae2 = 0.25 x 2Lp = 1.5 [m2]


Wind force on platform F2 = Iw x Cf x q x Cg x Ce x A = 3.9 [kN]

Base shear by wind F = F1 + F2 = 319.0 [kN]

Wind OTM to vessel bottom Mw1 = F1 x H5 + F2 x H = 5335.9 [kNm]

Wind OTM to mat bott surface Mw2 = F1 x (H5+H2+H3) + F2 x( H+H2+H3) = 5926.0 [kNm]

VESSEL TOP PLATFORM LIVE & SNOW LOAD




Top platform dead load DL = 2.000 [kPa] including framing

Snow load SL = 1.500 [kPa] and grating

Platform dead load = DL x Wp x Lp = 18.0 [kN]

Platform live load = LL x Wp x Lp = 43.2 [kN]

Vessel top snow load = SL x (π D2) / 4 = 301.6 [kN]

Since live load 4.8 kPa always override snow load, take max of live & snow load as live load

Max of platform live load and vessel top accumulated snow load = 301.6 [kN]

2H

3H

1L

4H

5H

CG

D

1H

H

pL

1F

2F


2010-05-25 Rev 1.2 Page 48 of 74

4 of 5

SEISMIC LOAD




ASCE Guidelines for Seismic Evaluation and Design of Petrochemical Facilities 1997 ASCE Seismic Guide


Vessel Data


Vessel operating weight Wop = 183710 [kN]

Vessel leg circle dia Dlegc = 22.500 [m]

Vessel leg number Np = 10


Vessel leg one side width L1 = 6.953 [m]

Leg support brace angle θ = 22.8Leg support brace length L = 17.905 [m]

Leg support brace section area Abr = 491 [mm2]

Vessel period is estimated based on tension/compression X brace

For tension only brace, the Ta is larger and the resulting seismic

force is smaller, thus it's conservative for design

Max froce in brace P = 47309.1 [kN]

Change in brace length Δ = 8415.6 [mm]

Hor. deflection when applying y = 21671.9 [mm]

Wop as lateral load Code Reference

Support struc period estimated Ta = = 9.344 [sec] ASCE Seismic Guide

Support struc period from STAAD Ta = = 3.765 [s] Page 4.A-10 Example 4

Support struc period used for desig Ta = = 3.765 [s]


Site location


Sa(0.2) = 0.120 Sa(0.5) = 0.056

Sa(1.0) = 0.023 Sa(2.0) = 0.006

Higher Mode Factor Mv and Overturning Reduction Factor J

Sa(0.2) / Sa(2.0) = 20.0 NBC 05

Mv = 1.50 J = 0.50 Table 4.1.8.11

Site Classification


Fort McMurray

Normal

y/g2π2

H3

H

1L

4H

5H

CG

tF

D

1H

H

tV - F

6H


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5 of 5

Code Reference


Fa = 1.300 Table 4.1.8.4.B

Fv = 1.400 Table 4.1.8.4.C


S(T=0.2s) = 0.156 4.1.8.1 (1)

S(T=0.5s) = 0.078 4.1.8.4 (6)

S(T=1.0s) = 0.032

S(T=2.0s) = 0.008

S(T=4.0s) = 0.004

S(Ta=3.76s) = 0.005 4.1.8.4 (6)


ASCE7-05


NBC 05

Vessel Operating Weight Wop = = 183710 [kN]

Seismic Base Shear VTa = S(Ta) Mv IE Wop / (Rd Ro) = 431.1 [kN] 4.1.8.11(2)

Vmin = S(2.0) Mv IE Wop / (Rd Ro) = 771.6 [kN]

Vmax = 2/3 S(0.2) IE Wop / (Rd Ro) = 6368.6 [kN]



Seismic force acting at 2/3H V-Ft = 578.7 [kN]

Vessel type

Vessel height above pedestal H = 30.000 [m]


Mat Thickness H2 = 1.200 [m]



Vessel CG height H5 = 26.000 [m]

If it's a sphere H6 = H5 = 26.000 [m]

If it's a ver. vessel H6 = 2/3 (H-H4) + H4 = 25.500 [m]

It's a Sphere H6 = = 26.000 [m]

Base Shear by Seismic V = 771.6 [kN]

Seismic OTM to pedestal Ms1 = [ Ft x H + (V-Ft) x H6 ] x J = 10416.4 [kNm]

Seismic OTM to mat bott surface Ms2 = [ Ftx(H+H2+H3)+(V-Ft)x(H6+H2+H3) ]xJ = 11130.1 [kNm]

No provision for nonbuilding struc in NBC05 Table 4.1.8.9. Use R=RdxRo=3.0 in ASCE7-05 for elevated vessel supported on symmetrically braced legs

Sphere

If Ta0.7 then Ft = 0.07TaV 0.12 seismic shall be considered


2010-05-25 Rev 1.2 Page 50 of 74

Design Example 04: Self-Supported Horizontal Vessel


Calculate the seismic force for a self-supported horizontal vessel

Vessel diameter OD= 3.683 m Insulation thk = 50mm

Vessel length = 20.700 m Vessel saddle distance = 16.535 m

Vessel empty weight = 533 kN

Vessel operating weight = 2317 kN

Site location : Fort McMurray

Site class : Class D

Structure importance category : Normal

NOTES



For lateral load on vessel longitudinal direction




2010-05-25 Rev 1.2 Page 51 of 74

1 of 7

DESCRIPTION

Horizontal vessel foundation design based on Code Abbreviation





INPUT


Vessel diameter OD = 3.683 [m]

Insulation thickness Tins = 50 [mm]

Vessel diameter for design D = 3.783 [m]

Vessel length L = 20.700 [m]

Saddle distance S = 16.535 [m]

Vessel center hei above footing H = 4.159 [m]

Back fill soil height H5 = 0.500 [m]

Platform width W1 = 2.000 [m]

Platform length L1 = 17.000 [m]

Saddle base plate width W3 = 0.660 [m]

Saddle base plate length L3 = 3.277 [m]

Saddle height H3 = 2.150 [m]

Anchor bolt spacing in width Wb = 0.305 [m]

Anchor bolt spacing in length Lb = 2.895 [m] PIP STE03360

min required Section 4.7.1

Pier height H2 = 1.960 [m]

Pier width W2 = 1.000 [m] 0.762 OK

Pier length L2 = 3.600 [m] 3.379 OK

Normal


2010-05-25 Rev 1.2 Page 52 of 74

2 of 7

WIND LOAD





Vessel Data Code Reference

Structure importance category Normal



Vessel length L = 20.700 [m]



Platform width W1 = 2.000 [m]

Platform length L1 = 17.000 [m]

Pier width W2 = 1.000 [m]

Pier length L2 = 3.600 [m]


Saddle width W3 = 0.660 [m]

Saddle length L3 = 3.277 [m]

Saddle height H3 = 2.150 [m]

Pilecap depth H4 = 0.900 [m]


Cg = 2.00 NBC05 4.1.7.1 (6)


2010-05-25 Rev 1.2 Page 53 of 74

3 of 7

Code Reference

TRANSVERSE WIND

Wind on Vessel and Misc

Dxsqrt (qCe) = 2.123 >0.167 L/D = 5.5 NBC05 Comment I


Ce = 0.90 NBC05 4.1.7.1 (5)

Add 1.5ft (0.46m) to OD to account for ladders, nozzles & piping attached to hor vessel ASCE Wind Loads

A = L x (D + 0.46) = 87.83 [m2] Section 4.3.2.2

NBC05 Comment I

Wind force on vessel FT1 = Iw x Cf x q x Cg x Ce x A = 42.9 [kN] Fig. I-24

Wind on Platform ASCE Wind Loads



Cf = 2.0 Section 4.3.2.6

Ce = 0.90 NBC05 4.1.7.1 (5)

Platform framing Ae1 = 0.25 x L1 = 4.3 [m2]

Front and back handrail Ae2 = 0.25 x 2L1 = 8.5 [m2]


Wind force on platform FT2 = Iw x Cf x q x Cg x Ce x A = 16.1 [kN]

Wind on Saddle Support ASCE Wind Loads

Cf = 2.0 Section 4.3.2.7

Ce = 0.90 NBC05 4.1.7.1 (5)

Two saddles projected area Ae = W3 x (H3 - D/2) x 2 = 0.3 [m2]

Wind force on saddle FT3 = Iw x Cf x q x Cg x Ce x A = 0.4 [kN]

Wind on Pier Support ASCE Wind Loads

Cf = 1.3 Section 4.3.2.7

Ce = 0.90 NBC05 4.1.7.1 (5)

Two piers projected area Ae = W2 x H2 x 2 = 3.9 [m2]

Wind force on pier FT4 = Iw x Cf x q x Cg x Ce x A = 3.2 [kN]

Trans. Wind Load Per Pier

Trans. base shear per pier FT = (FT1 + FT2 + FT3 + FT4)/2 = 31.3 [kN]

Trans. OTM to pier base per pier MTWP = [FT1H+FT2(H+0.5D)+FT3H2+FT4H2/2]/2 = 140.0 [kNm]

Trans. OTM to foot base per pier MTWF = add H4 to all lever arms above = 168.1 [kNm]


2010-05-25 Rev 1.2 Page 54 of 74

4 of 7

LONGITUDINAL WIND

Wind on Vessel and Misc ASCE Wind Loads

Cf = 1.20 Assume flat head to be conservative Section 4.3.2.4

Ce = 0.90 NBC05 4.1.7.1 (5)

Add 1.5ft (0.46m) to OD to account for ladders, nozzles & piping attached to hor vessel ASCE Wind Loads

A = π (D + 0.46)2 / 4 = 14.1 [m2] Section 4.3.2.2

Wind force on vessel FL1 = Iw x Cf x q x Cg x Ce x A = 10.7 [kN]

Wind on Platform ASCE Wind Loads



Cf = 2.0 Section 4.3.2.6

Ce = 0.90 NBC05 4.1.7.1 (5)

Platform framing Ae1 = 0.25 x W1 = 0.5 [m2]

Front and back handrail Ae2 = 0.25 x 2W1 = 1.0 [m2]


Wind force on platform FL2 = Iw x Cf x q x Cg x Ce x A = 1.9 [kN]

Wind on Saddle Support ASCE Wind Loads

Cf = 2.0 Section 4.3.2.7

Ce = 0.90 NBC05 4.1.7.1 (5)

Two saddle projected area Ae = L3 x (H3 - D/2) x 2 = 1.7 [m2]

Wind force on saddle FL3 = Iw x Cf x q x Cg x Ce x A = 2.1 [kN]

Wind on Pier Support ASCE Wind Loads

Cf = 1.3 Section 4.3.2.7

Ce = 0.90 NBC05 4.1.7.1 (5)

Two pier projected area Ae = L2 x H2 x 2 = 14.1 [m2]

Wind force on pier FL4 = Iw x Cf x q x Cg x Ce x A = 11.6 [kN]

Long. Wind Load Per Pier

Long. base shear per pier FL = (FL1 + FL2 + FL3 + FL4)/2 = 13.1 [kN]

Couple on pier caused by wind NL = [ FL1H3+ FL2 (H3+D/2) ] / S = 1.9 [kN]

Long. OTM to pier base per pier MLWP = 0.5(FL1+FL2+FL3) x H2 + 0.5FL4 x 0.5H2 = 20.1 [kNm]

Long. OTM to foot base per pier MLWF = add H4 to all lever arms above = 31.9 [kNm]


2010-05-25 Rev 1.2 Page 55 of 74

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SEISMIC LOAD






Vessel Data

Vessel operating weight Wo = 2317 [kN]

Pier width W2 = 1.000 [m]

Pier length L2 = 3.600 [m]




Footing height H4 = 0.900 [m]

Conc elastic modulus E = 2.5E+04 [MPa]

TRANSVERSE SEISMIC

L = H = 4.159 [m]

Ipier = W2 x L23 / 12 = 3.888 [m4]

Δ = Wo L3 / 3E Ipier = 0.572 [mm]

= 0.023 [in]

T = 0.32 sqrt( Δ ) = 0.048 [sec]

Rigid structure < 0.06 [sec]


Site location


Sa(0.2) = 0.120 Sa(0.5) = 0.056

Sa(1.0) = 0.023 Sa(2.0) = 0.006

Higher Mode Factor Mv

Sa(0.2) / Sa(2.0) = 20.0 NBC 05

Mv = 1.0 Table 4.1.8.11

Site Classification


Fort McMurray


2010-05-25 Rev 1.2 Page 56 of 74

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Code Reference


Fa = 1.300 Table 4.1.8.4.B

Fv = 1.400 Table 4.1.8.4.C


S(T=0.2s) = 0.156 4.1.8.1 (1)

S(T=0.5s) = 0.078 4.1.8.4 (6)

S(T=1.0s) = 0.032

S(T=2.0s) = 0.008

S(T=4.0s) = 0.004

S(T=0.04s) = 0.156 4.1.8.4 (6)

Structure Importance Category Normal NBC 05



Rigid structure (when T < 0.06) NBC 05

V = 2/3 S(0.2) IE Wo / (Rd Ro) = 80.3 [kN] 4.1.8.11(2)

Flexible structure (when T >= 0.06)

Seismic base shear VTa = S(T) Mv IE Wo / (Rd Ro) = 120.5 [kN] 4.1.8.11(2)

Vmin = S(2.0) Mv IE Wo / (Rd Ro) = 6.5 [kN]

Vmax = 2/3 S(0.2) IE Wo / (Rd Ro) = 80.3 [kN]


Rigid structure case applied

Seismic base shear V = 80.3 [kN]

Trans. Seismic Load Per Pier

Trans. base shear per pier VT = V / 2 = 40.2 [kN]

Trans. OTM to pier base per pier MTSP = VT x H = 167.0 [kNm]

Trans. OTM to foot base per pier MTSF = VT x (H + H4) = 203.2 [kNm]


No provision for nonbuilding struc in NBC05 Table 4.1.8.9. Use R=RdxRo=3.0 in ASCE7-05 for hor saddle supported steel vessel


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Code Reference

LONGITUDINAL SEISMIC NBC 05

L = H2 = 1.960 [m]

Ipier = L2 x W23 / 12 = 0.300 [m4]

Δ = Wo L3 / 3E Ipier = 0.775 [mm]

= 0.031 [in]

T = 0.32 sqrt( Δ ) = 0.056 [sec]

Rigid structure < 0.06 [sec]

S(T=0.05s) = 0.156 4.1.8.4 (6)

Seismic base shear VTa = S(T) Mv IE Wo / (Rd Ro) = 120.5 [kN] 4.1.8.11(2)

Vmin = S(2.0) Mv IE Wo / (Rd Ro) = 6.5 [kN]

Vmax = 2/3 S(0.2) IE Wo / (Rd Ro) = 80.3 [kN]


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