Restricción sísmica para equipamiento mecánico, James Tauby.

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Corporación de Desarrollo Tecnológico

Corporación de Desarrollo

Tecnológico

Asegurando continuidad de

operaciones: diseño sismo-resistente

para equipamiento mecánico de

edificios e industrias

James Tauby

www.cdt.cl 25 mayo 2010

“Restricción sísmica para

equipamiento mecánico”

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Control de Ruido

Control de Vibraciones Restricción Sísmica para Restricción Sísmica para equipamiento Mecánico

charla: Restricción Sísmica para Equipamiento Mecánico _charla: Restricción Sísmica para Equipamiento Mecánico

James Tauby, BSc. Ingeniero Mecánico 24 de mayo 2010 24 de mayo, 2010

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ll

“SEISMIC RESTRAINT OF

MECHANICAL SYSTEMS”

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ASHRAE SEISMIC RESTRAINT MANUAL

RP 812

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COMPARISON OF “G” FORCES

NEW YORK CITY HOSPITAL SANTIAGO, CHILE HOSPITAL SAN FRANCISCO HOSPITAL Rigidly Mounted

Boiler on Grade 0.18 G 0.5 G 0.45 G Rigidly Mounted

Rigidly Mounted

Boiler on Roof 0.29 G 0.79 G 0.72 G Spring Vibration

Isolated P mp 0 29 G 0 83 G 0 75 G Isolated Pump

on Grade 0.29 G 0.83 G 0.75 G Spring Vibration

Isolated

Pump on Roof 0.87 G 2.48 G 2.25 G S_s_s Value 0.425 1.65 1.50

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SPECIFICATIONS

“The Engineers Most Important Tool”

y The most important way to insure that a project in a y The most important way to insure that a project in a

seismic area is constructed as planned.

y Requires a properly prepared set of construction

documents (drawings and spec’s), detailed review, approval of shop drawings and field enforcement.

y Seismic restraint systems should be looked at as anSeismic restraint systems should be looked at as an

engineered system, not as a selection of hardware.

y The complete load path from the equipment to the

t t t b t k i t t b th i i

structure must be taken into account by the seismic restraint system.

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CONNECTION TYPES

Steel to Steel connections with bolts

Bolts should be designed to handle the

y

Bolts should be designed to handle the

appropriate shear and vertical forces

y

Bolts should be a minimum of Class 4 8 or

y

Bolts should be a minimum of Class 4.8 or

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CONNECTION TYPES

Steel to Concrete with Post Installed Anchors

Post Installed Anchors include Wedge Undercut

y

Post Installed Anchors include Wedge, Undercut

and Adhesive Anchors

y

Anchors must have been tested to the Guideline

y

Anchors must have been tested to the Guideline

for European Technical Approval of Metal

Anchors for Use in Concrete ETAG-001 or

American Concrete Institute’s ACI -355.2 to

insure seismic capability

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CONNECTION TYPES

Welding

y

Welding

y

Steel to Wood using lag bolts

L

b lt

t b d i

d i

d

ith

y

Lag bolts must be designed in accordance with

the “National Design Specification for Wood

Construction”

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HouseKeeping Pads

Called Plynth’s or Plinth’s in parts of the world

y

Called Plynth’s or Plinth’s in parts of the world

y

The most overlooked portion of equipment

installation is the housekeeping pads

y

They provide load transfer between the

equipment anchorage and the structure of the

building

y

Housekeeping pads need to be reinforced and

p g p

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HouseKeeping Pads

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HouseKeeping Pads

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HouseKeeping Pads

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HouseKeeping Pads

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HouseKeeping Pads

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HouseKeeping Pads

Fp up to 0 5 “G” Fp up to 0.5 G Housekeeping Pad

Area M2 _(FT2₎

Reinforcing Steel 300 mm (12”)

Perimeter Dowel Size 600mm Interior Dowel Size 900mm (36”) Maximum Combined Weight ( ) ( )

O.C.E.W. (24”) O.C. O.C.( ) kg (lbs)g Up to 3.7 (40) T8 (#3) M16 (5/8”) M16 (5/8”) 3,630 (8,000) 3.8 (41) to 9.3 (100)( ) ( ) T8 (#3)( ) M16 (5/8”)( ) M16 (5/8”)( ) 6,800 (15,000), ( , ) 9.4 (101) to 18.6 (250) T12 (#4) M20 (3/4”) M16 (5/8”) 11,340 (25,000) 18.7 (251) to 37 (400) T12 (#4) M24 (1”) M16 (5/8”) 22,675 (50,000)

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SUSPENDED PIPING

y All piping types require seismic bracing y All piping types require seismic bracing

y Pipe ductility helps decided the seismic performance of

the pipe system

y Weak links are at equipment and valve connections

y Steel and copper piping with welded or brazed joints are

extremely ductile and perform well Rp = 9 0 extremely ductile and perform well. Rp = 9.0

y Steel and copper piping with threaded, bonded,

compression or grooved joints do not perform as well as welded or brazed joints. Rp = 4.5

y Cast iron, plastic or glass piping joints do not perform

well. Rp = 3.0 well. Rp 3.0

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RIGID PIPE BRACING

y USES STEEL SECTIONS

OR STRUT CHANNELS

y CANNOT BE USED WITH

VIBRATION ISOLATED VIBRATION ISOLATED SYSTEMS

y CAUTION MUST BE

TAKEN WHEN USED ON TAKEN WHEN USED ON HOT WATER OR STEAM PIPING AS THEY MAY ACT AS ANCHORS

y LENGTH OF BRACE IS

DEPENDENT ON LOAD DEPENDENT ON LOAD

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RIGID PIPE BRACING

y Rigid bracing adds a

downward vertical force that adds to the gravity load and tries to pull the oad a d t es to pu t e hanger rod out of the

above structure.

y This does not happen on y This does not happen on

tension only cable bracing.

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CABLE PIPE BRACING

y Cable brace systems use

galvanized aircraft cable

y Can be used for both

vibration isolated and vibration isolated and non-vibration isolated systems

C ti h t b t k

y Caution has to be taken

with hot water or steam systems, cables can be installed slack for the anticipated thermal movements

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DUCT BRACING

All ductwork types (rectangular round and oval)

y

All ductwork types (rectangular, round and oval)

require seismic bracing depending on the size

y

Ductwork may be braced with either rigid or

y

Ductwork may be braced with either rigid or

cable bracing

y

Ductwork that is vibration isolated must use

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SUSPENDED EQUIPMENT

Q

All d d

i

t

i

y

All suspended equipment requires

seismic bracing depending on the size

y

Equipment may be braced with either

rigid or cable bracing

y

Equipment that is vibration isolated must

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RIGIDLY BRACED SUSPENDED

EQUIPMENT

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CABLE BRACED SUSPENDED EQUIPMENT

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SUSPENDED EQUIPMENT

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FLOOR MOUNTED EQUIPMENT

Q

y

Equipment must be attached to the structure

E i

t

b b lt d d

t th t

t

y

Equipment can be bolted down to the structure

y

Equipment can be held in position with seismic

snubbers

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FLOOR MOUNTED EQUIPMENT

Springs & seismic snubbers with Springs & seismic snubbers with

Q

anchorage designed for the seismic forces

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REFERENCES

y A Practical Guide to Seismic Restraint, ASHRAE, 1999

y 2007 ASHRAE Handbook, HVAC Applications, ASHRAE,

2007

y ASCE 7-05, Minimum Design Loads for Buildings and

Other Structures, American Society of Civil Engineers, Other Structures, American Society of Civil Engineers, 2005

y 2006 International Building Code, International Code

C il 2006 Council, 2006

y National Design Specification for Wood Construction,