11

WELCOME TO INHOUSE TRAINING SESSION

DESIGN OF PIPERACK

www.pipingfunda.com

2

CONTENTS

Introduction & Layout (DAY-1) Pipe Loading calculations for Pipe rack as per

Specifications Wind loading calculations as per IS:875-III Introduction to UBC-94 & its use for Calculation of

Loads for Pipe rack structure. Load Combinations for Design of Pipe rack Provisions of Project Specifications Concrete Design of Pipe rack Members (DAY-2) Introduction about IS:456 & SP:16 Provisions(DAY-3)

3

Introduction

What is called PIPERACK ? PIPERACK is a structure whose basic geometry is like a Portal Frame

having Multi-tiers which are provided to support piping , cable trays and (with) Fin fan coolers or (Without) coolers.

CLASSIFICATION OF PIPERACK Based on plant layout

ISBL (Inside Bat. Limit) & OSBL(Outside Bat. Limit)

Based on Utilities Supported Non Fin fan & Fin fan pipe rack

Based on Materials used for Members

Concrete (Pre cast or Cast-insitu) , Steel & Composite(Steel+Concrete)

4

Introduction & Layout

Following Preliminary Informations required from Piping

Screen dumps or P65 drawings showing C/s OF Piperack with different tiers & elevations.

Line size , Max. unsupported spacing/span ,Piping class & state(Hot or Cold), Flow direction i.e supply or Return , Insulation details

Space required for Electrical cable trays. Fireproofing requirement based on line contents for Steel Pipe rack

5

Introduction & Layout

Braced bay location:

Brace bay is nothing but it is bay supporting Piping anchor points.

Location shall be generally provided by Piping Specialist.

For Economy the anchor points for the same line shall be provided at staggering positions.

Expansion Bay :

Normally to be decided by Civil/Structural specialist. Normally the same shall be provided at every 40 to 50 Mt.

Longitudinal RC beam Elevations :

Normally to be provided in the center of Two tiers. Always Larger diameter of Pipes shall be routed near to Columns.

6

PIPERACK LOADING (REFERENCE : 3PS-CA-001)

For on-plot pipe racks minimum vertical load of 1.7 kN/m2 on plan area shall be applied at each pipe rack level, unless definitive loads are available from Piping Group. A concentrated load shall be added for pipes 12 in. dia. or larger.)

For off-plot pipe racks a vertical load of 2.5 kN/m² on plan area shall be applied at each pipe rack level, unless definitive loads are available from piping group. Concentrated loads for 14 in. dia. or 16 in. dia. pipes shall also be considered.

7

The horizontal friction load applied at each level shall be the greater of 7.5% of the total pipe weight or 30% of the operating pipe weight of any number of lines known to be

moving simultaneously in the same direction. For on-plot pipe racks the longitudinal beam struts shall be

designed for a vertical load of 50% of the load carried by the most heavily loaded transverse beam. This load should not be added to the design load for column or footings. For off-plot pipe racks, longitudinal beam struts shall be designed for vertical and horizontal loads imposed by expansion loops, located by piping group.

Introduction contd.

PIPERACK LOADINGS

8

PIPERACK LOADINGS

All pipe rack longitudinal beam struts shall be designed for a compression load of 15% of the maximum adjacent column load at beam level.

The horizontal load on pipe rack anchor bays shall be the greatest of:-

Anchor force from pipe stress (These shall include start-up and shutdown conditions). or

7.5% of piping vertical load between expansion joints or

40 kN applied uniformly at each level.

9

PIPERACK LOADINGS

Pipe rack designs shall be checked, when actual pipe loads, friction and anchor forces are known.

10

WIND LOADING CALCULATIONS

Wind loads acting on Pipe racks shall be in accordance with IS:875-III-1987

Basic Wind speed : Vb = 50 m/sec Risk coefficient -K1 = 1.08 Height & Terrain Factor K2 = Cat.2,Class-A,Table-2,IS875 Topographic factor k3 = 1.0 Design Wind speed Vz = Vb x K1 x k2 x k3 Design Wind Pressure Pz = 0.6 x Vz²

11

WIND LOADING CALCULATIONS

Wind force for Pipe rack Individual members Frame wise Individual Members

* Column & Beam Members(cl.6.3.3.2(b))

Normal force=Cfn x Pz x K x b ……..Kn/m

Transverse force=Cft x Pz x K x b ……..Kn/m

Cfn , Cft = force coefficients

K= Reduction factor for individual members(Table-25,pg.44)

b=width of member across wind direction

12

WIND LOADING CALCULATIONS

Wind force for Pipe rack Frame wise (CL.6.3.3.3 & 6.3.3.4)

Solidity ratio= area of members in direct exposure/Overall area

Force coefficients(for 1 Frame) = Reference table:28(pg.46)

for more than one frame

Frame spacing ratio =c/c dist of frames/least overall dim of frame measured at right angle to direction of wind

Refer Shielding factor based on solidity ratio & Frame spacing ratio(Refer Table:29 of Pg. No. 46 of IS:875-III)

13

WIND LOADING CALCULATIONS

Wind Force on Fin Fans

F (Total Wind Force) = Cf x Ae x Pz ……..Kn

Cf(Max) = Force coefficients =0.95 (Table:4)

Ae = Effective Frontal Area

14

WIND LOADING CALCULATIONS

WIND LOADINGS FOR PIPES

The transverse wind load on piping shall be applied on a projected area equal to the diameter of the largest pipe including insulation where applicable plus 10% of the usable width of the piperack, where the usable width of the piperack is defined as the distance between inside faces of piperack columns less clearance between columns and piping.

Where pipe sizes are unknown projected area shall be based on a 12 in. dia. pipe plus 50mm insulation.

15

Cable Tray Loads

A minimum cable tray load of 1.0 kN/m2 per tray layer shall be used for electrical/instrument trays.

The transverse wind load on cable trays shall be applied on a projected area equal to the height of the tray plus 10% of the net width of cable way dedicated to trays.

16

Introduction to UBC-94

International Conference of Building Officials(ICBO) Publishes the family of Uniform Building Codes

There are diff. Types of Uniform codes are available

Uniform Building Code : Volumes- 1,2,3 : The most Widely adopted model Building Code in the United States.

Volume-1 : Administrative , Fire and Life safety , Field Inspection provisions

Volume-2 : Structural Engineering Design provisions

Volume-3 : Material , Testing & Installation Standards

17

Seismic loads(As per UBC-1994)

V = Z x I x C / Rw (For Pipe rack structure) V= Design Base shear Z = Seismic Zone factor = for Zone-3 it is 0.3 (Table:16 I) (pg no.34) I = Importance factor = 1.25 (Table :16 K) (pg. No:35) C= Numerical Coefficient =1.25 x S / T 2/3 (Need not exceed 2.75) S=Soil Site Coefficient = 1.0 (Table :16 J) T= Fundamental period = Ct x hn 3/4 Ct = 0.0731 (For RC Mom. Frames),0.0853(Steel Moment

Frames),0.0488 for all other buildings hn = Height in meter above the base W = Dead & Normal operating gravity loads Rw = Response Modification Factor depending on OMRF,SMRF &

Braced bay types (Table :16 N)(Pg:37) Vertical distribution of base shear force shall be in accordance with

formulas (28-6) ,(28-7) & (28-8) of the UBC,Section-1628

18

Seismic loads(As per UBC-1994)

If T < 0.7 seconds Ft =0

If T > 0.7 seconds Ft =concentrated force @ top=0.07xTxV OR Need not exceed 0.25 V

Remaining Base shear Force shall be distributed as given below Fx = (V-Ft) x Wx x Hx / Sum( Wi Hi)

19

Seismic loads(As per UBC-1994)

V = Z x Ip x Cp x Wp (For Fin Fan ) Fp= Lateral Force Z = Seismic Zone factor = for Zone-3 it is 0.3 (Table :16 I , Pg. No. 34) Ip = Importance factor = 1.5 (Table :16K , Pg. No. 35) Cp= Horizontal Force Factor =0.75 (see note below) (Table :16O,Pg.38) Wp= Weight of Fin fan or component

NOTE : For flexibly supported fin fans with fundamental period greater than 0.06 seconds , use Cp equal to twice the value as shown.

20

LOAD COMBINATIONS (FOR RC DESIGN & FOUNDATION)

Erection Condition: (Don’t include wt. Of contenets)1. U = 0.9 x D + 1.3 x W (ACI) OR 1.5 x W (IS:456)2. U = 0.9 x D + 1.43 x W (ACI) OR 1.5 x W (IS:456) D= Empty load of piping shall be 60% of piping Test Condition: U = 1.4 x D + 1.4 x TL + 1.7 x L (ACI) OR 1.5 (D+TL+L) (IS:456)• U = 0.75(1.4D + 1.4 TL+ 1.7 L+0.5x1.7W) (ACI) OR 1.2(D+TL+0.5W)(IS456)Operating Condition: U = 1.4D + 1.7 L (ACI) OR 1.5(D+L) (IS:456)• U = 0.75(1.4D +1.7 L+1.7W) (ACI) OR 1.2(D+L+W) (IS:456)• U=1.4(D+L+E)(ACI) OR 1.2 (D+L+E)(IS:456)• U=1.4(D+T) (ACI) OR 1.5(D+T) (IS:456)• U=0.75(1.4D+1.4T+1.7L) OR 1.2(D+T+L)• U=0.75(1.4D+1.4T+1.7L+1.7W) (ACI) OR 1.2(D+T+L+W) (IS:456)• U=0.75(1.4D+1.4T+1.7L+1.87E)(ACI) OR 1.2(D+T+L+E) (IS:456)• Where U=Reqd. strength to resist factored loads in accoordance with

the ACI-318M & UBC OR IS:456

21

LOAD COMBINATIONS FOR CONNECTIONS

Connection Design as per UBC 1994 clause 2211.5.1 & 2211.8.3.1

37 or 38) DL + Oper. Load (+/-)3(Rw/8)xSeismic in N/S dir.(+/-)(Rw/8)xSL in E/W dir

39 or 40) DL + Oper. Load (+/-)3(Rw/8)xSeismic in E/W dir(+/-)(Rw/8)xSL in N/S dir

41 or 42) DL+Oper. Load+ 50%Live Load (+/-)3(Rw/8)xSL in N/S(+/-)(Rw/8)xSL in E/W

43 or 44) DL+Oper. Load+ 50%Live Load (+/-)3(Rw/8)xSL in E/W(+/-)(Rw/8)xSL in N/S

Column&Bracing Strength in Compression as per UBC 1994 clause 2211.5.1&2211.8.2.3

45 or 46) DL+Oper. Load+ 0.7xLive Load (+/-)3(Rw/8)xSL in N/S(+/-)(Rw/8)xSL in E/W

47 or 48) DL+Oper. Load+ 0.7xLive Load(+/-)3(Rw/8)xSL in E/W(+/-)(Rw/8)xSL in N/S

22

LOAD COMBINATIONS FOR CONNECTIONS

Column&Bracing Strength in Tension as per UBC 1994 clause 2211.5.1 & 2211.8.2.3

49 or 50) 0.85xDead Load (+/-)3(Rw/8)xSL in N/S(+/-)(Rw/8)SL in E/W dir 51 or 52) 0.85xDead Load (+/-)3(Rw/8)xSL in E/W(+/-)(Rw/8)SL in N/S

Column&Bracing Strength in Tension as per UBC 1994 clause 2211.5.1&2211.8.2.3

49 or 50) 0.85xDead Load (+/-)3(Rw/8)xSL in N/S(+/-)(Rw/8)SL in E/W dir

51 or 52) 0.85xDead Load (+/-)3(Rw/8)xSL in E/W(+/-)(Rw/8)SL in N/S

Manual Check Requirements as per UBC 1994

1. Slenderness Ratio Check as per clause 2211.8.2.1

2. Bracing Check for reduced permissible stress as per clause 2211.8.4.1.1

Note:Application of seismic force in both direction shall be checked by designer.

23

Example for strength check as per connection design forces

Column subjected to compression and Bending Moment (Example)

Section Used,Plate Girder 1200x25 + 400x45 (T&B)Column member subjected to Compressive force and bending MomentMaximum Axial compression = 4108.6 kNAllowable Axial compressive stress = 81.42 N/mm2Area of the Section Used = 63750 mm2Taken from STAADPro resultsAxial Compressive Strength = 1.7 x Fa x A as per UBC Clause 2211.4.2 = 8823.89kN

Hence, Safe Maximum Bending Moment =4368 kN.mFlexture Strength = Zp x Fy

Plastic Section Modulus of the section = Zp =2.85E+07mm3Yield stress of the material = Fy =250 N/mm2

Flexture Strength =7122.50 kN.m Hence, Safe