Seismic Analysis of Fire Sprinkler Systems

ABSTRACT: Post-earthquake functionality of fire sprinkler systems is critical for uninterrupted operation of the building;

however, fire sprinklers have experienced extensive damage during past earthquakes. Comprehensive research is required to

increase the understanding of the system level seismic performance of fire sprinkler systems subjected to realistic floor motions.

In this study, a complete fire sprinkler system including risers, main distribution lines, and pipe branches, and sprinkler heads

was analytically modeled using OpenSees. The model was subjected to the tri-axial floor responses of a three-story moment

resisting frame obtained from a nonlinear incremental dynamic analysis. The seismic performance of the fire sprinkler system

was assessed by statistically evaluating the relative displacement of sprinkler heads and peak forces in the seismic braces as a

function of peak ground acceleration. The response of the fire sprinkler system was shown to be effected by the direction of

excitation and seismic bracing. In addition, inelastic response of the supporting structure was shown to reduce both sprinkler

head displacements as well as seismic brace and wire restraint forces.

KEY WORDS: Fire Sprinkler; Seismic Response; Nonstructural Component, Piping, Fragility Functions.

1 INTRODUCTION

A buildings ability to remain operational after a significant seismic event is dependent not only on the performance of the

structural system but the functionality of several nonstructural

systems as well. One of these critical nonstructural systems is

the fire protection sprinkler piping system. Extensive damage

to fire sprinkler systems in several past earthquakes has

resulted in loss of functionality of many structures.

Fire sprinkler systems are susceptible to several forms of

earthquake damage. Inside the building, vertical pipes (risers)

can break under large inter-story drifts in the building.

Hangers supporting the weight of the pipe can unseat from

their attachment points. Fasteners connecting the hangers to

the building structure can pull out under seismic loading.

Sprinkler heads can break upon impact with adjacent

structural or nonstructural components, such as ceiling panels.

Couplings and pipe fittings can break or leak. Piping run

crossing separation joints that is not detailed for differential

movement can be ruptured, as can pipes that are

unintentionally restrained at locations where they pass through

walls [1]. Nearly all of these failure modes have been

observed in past earthquakes such as the 1964 Alaska

Earthquake; the 1971 San Fernando Earthquake; the 1989

Loma Prieta Earthquake; and the 1994 Northridge Earthquake

(Fig. 1). Damage to these systems may result in flooding,

leaking, loss of functionality, damage to neighboring

elements, and most importantly, loss of fire resistance.

Criteria for the protection of the sprinkler system first

appeared in NFPA 13 [2], Standard for the Installation of

Sprinkler Systems, in the 1940s. This guideline has gone

through several changes after the evaluation of facilities

following major earthquakes. The stringent expected seismic

performance of fire sprinklers necessitates special attention to

designing and detailing these systems. Comprehensive

research is yet required to increase the understanding of the

system level performance of fire sprinkler systems subjected

to realistic floor motions expected to occur in multistory

buildings during earthquakes.

Figure 1: Rupture of Sprinkler Pipe at the Elbow that in

Sylmar Hospital in 1994 Northridge Earthquake (Photo

courtesy of Robert Reitherman).

In this study, a complete hospital fire sprinkler system

including risers, main distribution lines, branches, sprinkler

heads, hangers, and braces was analytically modeled in

OpenSees [3] to investigate the influence of the type, quantity,

and distribution of seismic braces on the dynamic response of

fire sprinkler systems. The effect of nonlinear structural

response was included in the investigation as well through the

implementation of floor response excitations obtained from an

incremental dynamic analysis of a three-story hospital

building.

Fire sprinkler piping systems are sensitive to both

acceleration and deformation [4]. Thus, for a system installed

in a multistory building, horizontal pipe runs are necessary to

Seismic Analysis of Fire Sprinkler Systems

Siavash Soroushian1, Arash E. Zaghi

1, Joe Wieser

1, E. Manos Maragakis

1, Gokhan Pekcan

1, Ahmad Itani

1

1Department of Civil and Environnemental Engineering, University of Nevada, Reno MS258, 89557 Reno, USA

email: [email protected],[email protected], [email protected], [email protected], [email protected], [email protected]

Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011Leuven, Belgium, 4-6 July 2011G. De Roeck, G. Degrande, G. Lombaert, G. Muller (eds.)ISBN 978-90-760-1931-4

411

be modeled along with riser pipes that connect the horizontal

runs and span between floors. Such a model accounts for the

effects of differential floor motions of the building. For this

study, a full 3D model comprising all three floors of the fire

sprinkler system was investigated.

The analytical model was subjected to the tri-axial floor

responses of a three story moment resisting frame hospital

building that was obtained from a series of nonlinear

incremental dynamic analyses (IDA) [5]. The response of the

sprinkler system was obtained in terms of the maximum

relative displacement of sprinkler heads and forces in the

seismic braces and wire restraints. Accordingly, probability of

exceedance from certain demand levels were found at

different peak ground acceleration (PGA) levels.

2 METHOD OF ANALYSIS

To capture the influence of the dynamic response of the parent

building on the response of the installed fire sprinkler system,

a three story hospital building was analyzed. The IDA method

[5] was used to capture the seismic response of the hospital

building from elastic ranges up to imminence of failure (inter-

story drifts as large as 7%).

Afterwards, the floor motions obtained from the analysis

were introduced to the full model of fire sprinkler system as

multiple support excitations. The analytical model of the

sprinkler system comprised all the elements of the system

such as braces, hangers, main runs and branches, risers, and

sprinkler heads. Linear analyses were performed on the

sprinkler system under the same sequence of floor motions

that were obtained from the IDA analysis of the hospital

building.

By this means, the effects of linear and nonlinear response

of the parent building were realistically accounted for. In this

method, the dynamic interaction the building and sprinkler

systems is neglected that is not far from reality, since the mass

and stiffness of the subsystems is negligible compared to

those of a building.

3 COMPUTATIONAL MODEL OF THREE-STORY HOSPITAL BUILDING

3.1 Specifications of the Building

A special moment resisting frame (SMRF) hospital building

was analyzed. Hospital structures are unique because after a

seismic event, they are required to stay operational with

minimal interruption. Hospital buildings contain a large

number of nonstructural components most of which are

crucial for the functionality of the hospital.

The plan view and elevation of this three-story hospital is

presented in Fig. 2. This hospital building was designed as a

part of this research after SAC three-story office building.

SAC building had been designed as part of project performed

by SAC Steel Joint Venture [6]. SAC office building was

redesigned according to the 2006 International Building Code

[7] to satisfy the design requirements of the seismic design

category D. The plan dimensions mimic that of SAC building

while the elevation was adjusted to be more representative of

current hospital buildings. It has plan dimensions of 180 ft

[54.8 m] by 120 ft [36.6 m]. The story heights were adjusted

to 20 ft [6 m], 16 ft [4.9 m] and 16 ft [4.9 m] making the

building 52 ft [15.8 m] tall. The lateral load-resisting system

is comprised of four 3-bay perimeter SMRFs, as shown with

bold lines in Fig. 2, with simple framing between them.

Figure 2: Geometry of the Hospital Building

3.2 OpenSees Model

The main goal for the analysis of the building was to assess

the bi-directional floor responses of yielding building

structures under all three components of seismic excitation by

accounting for the out-of-plane flexibility of floor decks. With

these objectives in mind, utilization of three-dimensional

models with explicitly modeled gravity framing system and

floor slabs was necessary. The floor decks were modeled

using two-dimensional area elements. The gravity framing

system was included for the same reason.

OpenSees nonlinear analysis software [3] was used for

including material and geometric nonlinearities (P-Delta

effects). The beams and columns were modeled using Force-Based Beam-Column frame elements and a Fiber Section object was assigned to these elements. Each Fiber Section object was composed of nine fibers (three on each flange and

three on the web). Steel02 uniaxial material was used with yield stress of 50 ksi [345 MPa] and strain hardening of 2% of

the elastic stiffness. Centerline dimensions were used to

define the model. The fundamental period of the hospital

building was 1.0 sec. For time history analysis, Rayleigh

damping was applied and a 5% damping ratio was assigned to

0.8 and 2.0 times the fundamental period.

3.3 Input Motions

The ATC-63 project developed a set of 22 far-field ground motions from recorded seismic events taking place around the

world [8]. These motions were collected for the purpose of

performing incremental dynamic analysis to develop the

collapse margin ratio of a structure [8]. Though this

investigation is not interested in studying seismic capacity of

buildings, the set of motions has been deemed appropriate for

use with incremental dynamic analysis, and as such was

adopted for this investigation. Table 1 shows the names,years,

magnitudes, PGAs, and the name of the recording station.

Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011 412

Table 1: Ground Motions

Earthquake Recording Station PGA

(g) Name Year Mag. Name

Northridge 1994 6.7 Beverly Hills-Mul. 0.517

Northridge 1994 6.7 Canyon Country-WLC 0.482

Duzce, Turkey 1999 7.1 Bolu 0.822

Hector Mine 1999 7.1 Hector 0.337

Imperial Valley 1979 6.5 Delta 0.351

Imperial Valley 1979 6.5 El Centro Array #11 0.380

Kobe, Japan 1995 6.9 Nishi-Akashi 0.509

Kobe, Japan 1995 6.9 Shin-Osaka 0.243

Kocaeli, Turkey 1999 7.5 Duzce 0.358

Kocaeli, Turkey 1999 7.5 Arcelik 0.219

Landers 1992 7.3 Yermo Fire Station 0.245

Landers 1992 7.3 Coolwater 0.417

Loma Prieta 1989 6.9 Capitola 0.529

Loma Prieta 1989 6.9 Gilroy Array #3 0.555

Manjil 1990 7.4 Abbar 0.515

Superstition Hills 1987 6.5 El Centro Imp. Co. 0.358

Cape Mendocino 1992 7 Rio Dell Overpass 0.549

Chi-Chi, Taiwan 1999 7.6 CHY101 0.440

Chi-Chi, Taiwan 1999 7.6 TCU045 0.512

San Fernando 1971 6.6 LA-Hollywood 0.210

Friuli 1976 6.5 Tolmezzo 0.351

Minimum 1971 6.5 - 0.210

Maximum 1999 7.6 - 0.822

Average - 7.0 - 0.424

Figure 3: Acceleration Spectra the Input Motions

The 5% damped elastic acceleration spectra of the major,

minor, and vertical components are presented in Fig. 3,

respectively. All three components of the ground motion were

used to excite the structure with the major component of the

applied ground motion oriented in the long-direction, the

minor component in the short-direction, and the vertical

component in the z-direction. This orientation was consistent

for all 21 events.

3.4 IDA Analysis Results

The scaling method developed by Vamvatsikos and Cornell

[5] was used after minor modification to find a data point

within the predetermined drift range. The drift window for

this study was set between 5% drift and 7% drift. Figure 4

shows the IDA curves that were obtained by fitting SP-Lines

on data points. Figure 4 shows the IDA curves for the

maximum inter-story drift and peak roof acceleration. The

smaller rate of increase in roof acceleration in larger motions

is a result of yielding of the structure.

Figure 4: IDA Results

4 COMPUTATIONAL MODEL OF FIRE SPRINKLER PIPING SYSTEM

4.1 Specifications of Fire Sprinkler Piping System

The dimensions and layout of fire protection piping systems

are individualized for each building and vary based on the

architecture and occupancy of the parent building.

Consequently, selecting a generic fire piping system was

somewhat arbitrary. The fire piping system modeled in this

study is a portion of the fire sprinkler system in the UCSF

Medical Center Hospital Building. As part of the fire

protection sprinkler system of a 15-story hospital structure,

the selected piping layout is quite robust. It incorporates a

variety of commonly used components such as distribution

mains of various diameters, branch lines of various diameters,

hangers, seismic braces, wire restraints, tee joints, elbow

joints, pipe reduction joints, and sprinkler heads. It also

0.0

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Sa (g

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Sa (g

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Events

Minimum

16th %

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84th %

Maximum


contains a sufficient quantity of each of these commonly used

components to statistically evaluate the seismic performance

of each type of component in the system.

Figure 5: Plan View of Fire Piping System

A plan view of the modeled portion of the sprinkler system

is shown in Fig. 5. The plan layouts are consistent between

floors and are connected to a 6 in. [150 mm] riser located at

the top end in Fig. 5. A penolum height (the height between

the supporting floor and the ceiling system) of 4 ft [1.2 m]

was assumed for each floor. The pipe system was suspended

2.5 ft [762 mm] below the supporting floor and the sprinkler

drops 1.5 ft [458 mm] to the ceiling height. The 82 ft [25 m]

main distribution line varies in diameter from 4 in [100 mm]

at the connection to the riser to 2 in [50 mm]. at the end of the

main. The main distribution line feeds 16 branch lines ranging

in diameter from 1-1/2 in. [38 mm] to 1 in. [25 mm]. The

main and branch lines supply 47 sprinkler heads. The

sprinkler pipe system is connected to the supporting floor with

a combination of 12 seismic strut braces, 54 vertical hangers,

and 80 wire restraints. The seismic braces consist of a 1 in.

[25 mm] diameter strut oriented in a 45 degree angle from the

supporting floor such to provide lateral bracing in one

direction to the pipe Fig. 6. The vertical hangers are 3/8 in.

[10 mm] threaded rods as required for pipes of 4 in. [100 mm]

in diameter or less per the NFPA 13 [2]. Lateral restraint at

the ends of branch lines was provided by a set of 1/8 in [3

mm] wire restraints Fig. 6. Each of the four wires used in the

restraint are made of aircraft grade steel with minimum break

strength of 1700 lb [7.5 kN].

4.2 OpenSees Model

The objective of the fire piping system model was to identify

the relative displacement demands on sprinkler heads and

force demands in seismic braces and wire restraints of an

elastic fire sprinkler system under realistic tri-axial differential

floor motions. This required an elastic model of the three floor

fire piping system shown in Fig. 7.

(1)

(2)

Figure 6: Pipe Bracing: 1) Seismic Brace, 2) Wire Restraint

Developed in OpenSees [3], the model consists of two types

of elements. All of the pipes (riser, mains, and branches) are

modeled using Force-Based Beam-Column elements with elastic sections. The seismic braces, hangers, and wire

restraints were modeled with elastic truss elements. All of the

elements are made of steel with a modulus of elasticity of

29,000 ksi [200 GPa]. The mass of the piping system was

determined using the wet weight of the pipes, assuming a

sprinkler head weight of lb. [0.25 kg]. Both the mass and

weight were evenly distributed along the length of each pipe

element and the mass of the sprinkler heads was concentrated

at the nodal locations of the sprinkler heads. Centerline

dimensions of the piping system were used to define the

elements. All pipe to pipe connections were assumed to be

continuous while the braces, hangers, and wires were assumed

to be pin-ended truss members. The connection of the riser to

the ground level was such that no moment demand was

imposed on the base of the riser pipe. No special connection

details were used in this basic elastic model of the sprinkler

piping system. The stiffness of the pipe elements was


determined from their respective cross section and does not

account for the influence of the internal pressurized water.

The stiffness of the seismic braces and vertical hangers were

also based on the cross sectional properties, but the stiffness

of the wire restraints was modified to 10% of their full

stiffness to compensate for initial slack. This reduction in

stiffness was based on the recommendation of Zaghi et al. [9].

A Rayleigh damping matrix was used in the piping model and

3% damping was assigned to the first and third modes. The

fundamental period of the piping system was 0.8 seconds and

the shape of its fundamental mode had a peak amplitude in the

middle of the second branch from the top on the left side of

Fig.5.

4.3 Input Motions

Once the fire sprinkler model was defined, multiple support

excitation was used to induce the inertial forces. The input

motions for each floor level of the piping model coincided with

the response motion of the previously modeled inelastic three-

story hospital building. All three orthogonal axes of building

response were used to excite the piping model. The major

component of the ground motion and long direction of the

building were aligned with the axis perpendicular to the main

distribution lines of the piping system. The vertical floor

excitation corresponds to the vertical response of a point along

a gravity load carrying beam in each floor of the three-story

hospital building.

In total, 320 time history analyses of the piping system were

performed, 21 events each scaled to at least 11 different

intensities. In this manner, a variety of structural responses of

the hospital building, ranging from elastic to near collapse, were

introduced to the piping system.

Figure 7: Three Dimensional View of Fire Piping Model

5 ANALYTICAL RESULTS

5.1 Data Analysis Methodology

Post-processing the data from 141 sprinkler heads, 36 seismic

braces, and 240 wire restraints required a well defined statistical

approach. First, all of the peak sprinkler head displacements,

peak seismic braces, and peak wire restraint forces from each

analysis were plotted in scatter form and determined to have a

log-normal distribution. A sample scatter plot is presented in

Fig.8. Then, using a log-normal distribution cumulative

probability function the probability of exceeding predetermined

levels of response were calculated and plotted against the peak

ground acceleration.

The results presented explore the influences of excitation

directivity and inelastic response of the supporting structure on

the fragility of components of the fire sprinkler system. In order

to highlight the effect of nonlinear response of the supporting

structure analysis results from low intensity motions (elastic

response) were scaled up to higher intensities and compared

with the results which include inelastic response of the

structure.

Figure 8: Dispersion of Sprinkler Head Displacement along

Short Axis

5.2 Relative Displacement of Sprinkler Heads

The geometry of typical fire sprinkler heads is such that the

center of the sprinkler head is located in the center of a 2 in.

diameter ring in the ceiling [10]. If the ceiling is assumed to

move rigidly with the supporting floor slab, the relative

displacement of the sprinkler head is limited to 1 in. before it

makes contact with the ceiling and has the potential of

breaking. This study investigates the characteristics of the

relative displacement of sprinkler heads during both elastic and

inelastic building response and quantifies the potential of

sprinkler head failure due to contact with the ceiling system.

The time history relative displacement response of similar

sprinkler heads located on each of the three floors is compared

in Fig. 9. The response of the sprinkler heads under low

intensity ground excitation (PGA = 0.055 g) was considerably

different compared to the same event at a higher intensity (PGA

= 1.805 g).

Under the low intensity motion the building responds

elastically therefore there is a linear correlation between the

responses of each floor which carries through to the response of

the elastic piping system. This observation is clear in Fig. 9a, in

which the responses of similar sprinkler heads at each level

were in phase with one another and increase in amplitude with

increasing floor level. The elastic response of the hospital

building was dominated by the first mode of vibration, thus

explaining the increasing amplitude in sprinkler head

displacement due to increased acceleration response of the

parent building throughout the height.

When the intensity of the ground excitation exceeded the

elastic capacity of the hospital building, the linear correlation

between floor responses was lost. As a result, the floor

0.00254

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excitations imposed on the piping system no longer were in

phase with one another due to changing modal response

characteristics as the building yields. This is observed clearly in

the sprinkler head response shown in Fig. 9b. Contrary to the

elastic response, the peak relative displacement of the

sprinkler head located on the first floor is greater than that on

the third floor. This is due to the deamplification of the

ground motion throughout the height of the building as a

result of yielding.

Figure 9: Sprinkler Head Displacement History along Short

Axis (a) Elastic Building Response (b) Inelastic Building

Response

In order to quantify the potential of sprinkler head failure

due to contact with the ceiling, the probability of exceeding

in. and 1 in. of relative displacement in each horizontal

direction was plotted against the peak ground acceleration of

each direction, as shown in Fig. 10.

There is clearly a directivity influence on the potential of

making contact with the ceiling. This particular fire sprinkler

system was more vulnerable to acceleration along its short

axis then along its long axis. Due to the well braced nature of

the piping system along its short axis and limited bracing

perpendicular to several branches, the probability of

experiencing large sprinkler head displacements along the

long axis was greater than along the short axis. Several

sprinkler heads were observed to experience relative

displacements in the long direction of up to 5 times that of the

short direction. The location of these peak displacements was

at sprinkler heads of unbraced branches, the same branches

that had large amplitudes in the fundamental mode shape.

These branches that were thought to be susceptible to large

displacements have been proven to in fact experience

extremely high displacement demands which may lead to

failure of sprinkler heads attached to these unbraced branches

as they contact the ceiling or other surrounding systems.

Figure 10: Influence of Directivity on Probability of Sprinkler

Head Displacements Exceeding 1/2 in [12.5 mm] (EL 1) and 1

in [25 mm] (EL 2)

Similar plots were developed to assess the influence of

inelastic response of the supporting structure. Figure 11 plots

the potential of exceeding 1 in. of relative displacement in the

major direction for both an elastic and inelastic supporting

structure. The potential of exceeding a predetermined

displacement limit was reduced when the supporting structure

is allowed to yield. The increased level of yielding in the

supporting structure damps the acceleration response of its

floors thus reducing the input to the sprinkler piping system.

Figure 11: Influence of Structural Inelasticity on Probability

of Short Axis Sprinkler Head Displacements Exceeding 1 in

[25 mm]

5.3 Wire Restraint Forces

Performing a similar analysis of the wire restraints required

the determination of sample limit states of the wire restraints.

The breaking force of the wire restraints was specified as

1700 lb. thus 60% of the breaking force was used to define the

design force for the wire restraints. Limit states of 15%, 50%,

and 100% of the design force were set.

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of Wire Restraint Forces Exceeding 15% (EL 1), 50% (EL 2),

and 100% (EL 3) of Their Design Force

The likelihood of exceeding each of these limit states is

plotted against the peak ground acceleration for each direction

in Fig. 12. The wire restraint forces, similar to the sprinkler

head displacement, show a profound influence of directivity.

The difference, however, is that while the sprinkler head

displacements in the major direction were significantly less

than those in the minor direction the opposite is true for the

wire restraint forces, and vice versa in the alternate direction.

This shows that while providing seismic restraint limits the

displacements it increases the force demands on the restraints.


of Wire Restraint Forces along the Short Axis Exceeding

100% of Their Design Force

Similar to the sprinkler head displacements the influence of

inelastic response of the supporting structure reduce the

demands of fire sprinkler system. Figure 13 presents the

comparison of the probability of exceeding the design force of

the wire restraints in the minor direction under elastic and

inelastic response of the supporting structure. Interestingly,

the data seems to follow a linear trend for the elastic building

response, as expected, but for the inelastic building response

the data shows a decreasing trend for very strong ground

excitations. This means that there comes a point where the

structure has become so ductile that the acceleration demand

on the fire sprinkler piping system is less than the ground

acceleration.

5.4 Seismic Brace Forces

The last components examined in this investigation were the

forces in the seismic braces. For these components the design

force was determined from the critical buckling capacity of

the 1 in pipe section used as the seismic braces. The design

force of 6.3 kips was calculated and similar to the wire

restraint limit states 15%, 50%, and 100% of the design force

were defined as the force demands of interest.


of Seismic Brace Forces Exceeding 15% (EL 1), 50% (EL 2),

and 100% (EL 3) of Their Design Force

Figure 14 illustrates the influence of directivity on the

potential of exceeding each of the force limits. Similar trends

to the wire restraint forces were identified. However, the data

for the seismic brace forces show slightly more scatter due to

the relatively small number of seismic braces in the fire

sprinkler plan.


of Seismic Brace Forces along the Long Axis Exceeding

100% of Their Design Force

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The reduction of force demands due to inelasticity in the

supporting structure was shown again for the seismic brace

forces in Fig. 15. A more significant influence of the building

inelasticity was observed in the likelihood of exceeding the

seismic brace design force than that shown in the wire

restraints.

6 CONCLUSIONS

This investigation examined the performance of an elastic

hospital fire sprinkler system under realist tri-axial multi-

support excitation. Using an uncoupled analysis approach in

which a three-story hospital building was analyzed using

nonlinear IDA for a set of 21 far-field ground motions and the

ensuing floor responses were used to excite three levels of a

fire sprinkler system, the displacement demands on the

sprinkler heads along with the force demands in the seismic

braces and wire restraints were assessed. Significant influence

of geometry were identified, most critically the effect of

limited bracing on pipe branches may decrease force demands

while greatly increasing sprinkler head displacement

demands. The effect of yielding in the supporting structure

was assessed. It was concluded that increased levels of

yielding in the supporting structure reduces both sprinkler

head displacement demands as well as seismic brace and wire

restraint forces. Also, the effect of unbraced branches was

shown to significantly increase the peak sprinkler head

displacements. In total this investigation has laid the ground

work for more comprehensive investigations of the seismic

performance of fire sprinkler systems.

ACKNOWLEDGMENTS

This material is based upon work supported by the National

Science Foundation under Grant No. 0721399. Any opinions,

findings, conclusions or recommendations expressed in this

document are those of the investigators and do not necessarily

reflect the views of the NSF. The input provided by the

Practice Committee of the NEES Nonstructural Project,

composed of W. Holmes (Chair), D. Allen, D. Alvarez, and R.

Fleming; by the Advisory Board, composed of R. Bachman

(Chair), S. Eder, R. Kirchner, E. Miranda, W. Petak, S. Rose

and C. Tokas; and by the other members of the Experimental

Group, A, Filiatrault, G. Mosqueda, A. Reinhorn, and J. T.

Hutchinson, has been crucial for the completion of this

research. The authors are especially grateful to Abhinav Gupta

for providing the piping plan.

REFERENCES

[1] SEAOC Seismology Committee. SEAOC Blue Book: Seismic Design Recommendations. Sacramento, CA, 2006.

[2] NFPA 13 Standard for the Installation of Sprinkler Systems, National Fire Protection Association, 2010 edition, Quincy, MA, 2011.

[3] OpenSees Ver. 2.2.2f Open System for Earthquake Engineering Simulation, http://opensees.berkeley.edu/, Berkeley, CA, 2010.

[4] Federal Emergency Management Agency Reducing the Risks of Nonstructural Earthquake Damage, FEMA E-74, U.S. Department of Homeland Security, Washington, DC, 2010.

[5] Vamvatsikos, D., & Cornell, C. Applied Incremental Dynamic Analysis. Earthquake Spectra , 20 (2), 2004.

[6] Gupta, A., Krawinkler, H., Seismic Demands for Performance Evaluation of Steel Moment Resisting Frame Structures, John A. Blume Earthquake Engineering Research Center Report No. 132, Department of Civil Engineering, Stanford University, 1999.

[7] ICC. International Building Code. International Code Council, Falls Church, VA, 2006.

[8] FEMA P695 Quantification of Building Seismic Performance Factors, Federal Emergency Management Agency, Washington, D.C., 2009.

[9] Zaghi, A., Maragakis, E., Itani, A., & Goodwin, E. Experimental and Analytical Studies of Hospital Piping Assemblies Subjected to Seismic

Loading. Earthquake Spectra, In Press, 2011. [10] E 580/E 580M-09a Standard Practice for Installation of Ceiling

Suspension Systems for Acoustical Tile and Lay-in Panels in Areas

Subject to Earthquake Ground Motions. West Conshohocken, PA, 2009.


Seismic Analysis of Fire Sprinkler Systems

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