Seismic Capacity of Threaded, Brazed and Grooved Fire Protection Pipe Joints

2012 ◽  
Author(s):  
Brent Gutierrez ◽  
George Antaki
Keyword(s):  
Fire Protection ◽  
Failure Modes ◽  
Shake Table ◽  
Dynamic Failure ◽  
Lateral Loads ◽  
Seismic Capacity ◽  
Shake Table Tests ◽  
Protection Systems ◽  
Pipe Joints ◽  
In Fire

A series of static and shake table tests were conducted on pressurized threaded, brazed and mechanical, i.e., grooved pipe joints, commonly used in fire protection systems. The objective of the tests was to understand the behavior and failure modes of these common types of joints under seismic and static lateral loads. The paper presents the measured loads and deflections of the joints up to the point of failure. It also describes the joints’ static and dynamic failure modes. While this information may be limited it can be used to model the joint flexibility under large lateral loads, determine their capacity, and help understand the leak and rupture characteristics of threaded, brazed and clamped joints.

Seismic Capacity of Threaded, Brazed and Grooved Clamped Joints

2004 ◽  
Author(s):  
George Antaki
Keyword(s):  
Shake Table ◽  
Ultimate Capacity ◽  
Lateral Loads ◽  
Seismic Capacity ◽  
Shake Table Tests ◽  
Protection Systems ◽  
Pipe Joints ◽  
Lateral Displacements ◽  
In Fire ◽  
Large Earthquakes

A series of static and shake table tests were conducted on threaded, brazed and mechanical pipe joints, commonly used in fire protection systems, to understand their integrity under extreme lateral loads, of the type that would be expected in large earthquakes. This paper presents the measured loads and deflections of the joints up to the point of failure. It also describes the joints’ static and dynamic failure mode. This information can be used to model the joints’ flexibility under large lateral displacements, determine their ultimate capacity, and help understand their leak and rupture characteristics.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane, and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2007 ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending ◽  
The Difference

In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3-D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned wall elbow, because the life of piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

Experimental Study on Strength of Connections to Concrete Filled Tubular in Fire

2011 ◽  
Vol 299-300 ◽  
pp. 743-746
Author(s):  
Hong Jun Sun ◽  
Li Hong Zhao
Keyword(s):  
Experimental Study ◽  
Fire Protection ◽  
Failure Modes ◽  
Steel Beams ◽  
Steel Beam ◽  
Catenary Action ◽  
Tubular Columns ◽  
In Fire ◽  
Sufficient Strength ◽  
Very High

Concrete filled tubular columns are widely used all over the world, due to their significant advantages, including attractive appearance, structural efficiency, reduced column footing, fast construction and high fire resistance without external fire protection. An experimental study has been carried out on the performance of joints between steel beams and concrete filled tubular columns in simple construction under fire conditions. The failure modes of the test specimens were always in the joint regions. Therefore, if the joints are appropriately designed and protected so that they possess sufficient strength, it is possible for the steel beam to develop catenary action and survive very high temperatures even without fire protection.

In-Plane Shake-Table Testing of GFRP-Strengthened Concrete Masonry Walls

2007 ◽  
Vol 23 (1) ◽  
pp. 223-237 ◽  
Author(s):  
Martin Turek ◽  
Carlos E. Ventura ◽  
Steven Kuan
Keyword(s):  
Failure Modes ◽  
Concrete Block ◽  
Masonry Walls ◽  
Shake Table ◽  
Shake Table Tests ◽  
Glass Fiber Reinforced Plastic ◽  
Earthquake Records ◽  
Glass Fiber Reinforced ◽  
Reinforced Plastic ◽  
Ultimate Failure

In-plane shake-table tests were performed on eight full-scale unreinforced concrete block walls. Three of the walls were left as plain unreinforced masonry and five were strengthened using glass-fiber-reinforced plastic (GFRP) strips in four different configurations. All walls were first subjected to design-level earthquake records to determine the improvement obtained from the addition of the GFRP. The walls were then subjected to extreme-level earthquake records to examine the ultimate failure modes and the effects of the various GFRP configurations on the response of the walls. It was observed that all strengthened specimens performed well during the design-level shaking, and three of the four GFRP configurations also performed well during the extreme-level shaking. The tests showed that the use of vertical GFRP strips alone is able to improve the in-plane performance of URM walls. The strips were also able to control the failure modes, and prevent collapse after severe damage, improving significantly the life safety performance of URM walls.

Water Hammer Analysis/Prevention/Mitigation in Fire Protection Systems at Power Plants

2003 ◽  
Author(s):  
Asif H. Arastu ◽  
Eugene Tom
Keyword(s):  
Fire Protection ◽  
Nuclear Power ◽  
Power Plants ◽  
Void Formation ◽  
Water Hammer ◽  
Mitigation Strategies ◽  
Physical Damage ◽  
Protection Systems ◽  
Piping Networks ◽  
In Fire

Fire Protection water systems are typically piping networks where water is pumped from a low elevation reservoir at atmospheric pressure to higher elevations in the buildings served by the system. Because of this nature of their design, they are prone to water hammers due to water column separation & rejoining. A loss of pressure can lead to void formation at high elevations whose collapse can result in severe water hammer. A damaging water hammer event that occurred at a nuclear power plant (Arastu, et al, 1999) causing a catastrophic valve failure pointed to the need to prevent and mitigate such potential events at other plants. One important aspect of that event is that prior to it, several events of similar magnitude had occurred that did not apparently cause physical damage but degraded the system sufficiently to make it susceptible to damage. This paper discusses the causes of water hammer in Fire Protection Systems at power plants and identifies analysis, prevention, and mitigation strategies. Using a Method Of Characteristics based program, computer simulation results of the application of the mitigative measures are given for three large plant systems to demonstrate the effectiveness of the measures proposed at these plants.

scholarly journals Differences between standards related to fire protection systems design

Tehnika ◽  
2021 ◽  
Vol 76 (3) ◽  
pp. 386-392
Author(s):  
Radoje Jevtić
Keyword(s):  
Fire Protection ◽  
Material Properties ◽  
Systems Design ◽  
Protection Systems ◽  
The World ◽  
In Fire

Fire protection and design of fire protection systems present very important engineering tasks in protection of human lives, animals and material properties. Because of its great significance, everything in fire protection and fire protection systems design must be defined by appropriate standards. There are several different standards in use in different countries around the world. Very often, in solvation of different fire protection tasks, there are many questions asked which standard should be used. There are many similarities between standards, but there are also many differences between standards. Also, some standards don't define at all some cases that can be found in fire protection. This paper was written to present solutions for some particular tasks by some valid standards (EN 54, BS, NPB 88-2001, VDE 088-2 and NFPA 72) in fire protection and differences between them in the same cases.

Shake Table Testing of Seismically Restrained Clay-Brick Masonry Parapets

2018 ◽  
Vol 34 (1) ◽  
pp. 99-119 ◽  
Author(s):  
Marta Giaretton ◽  
Dmytro Dizhur ◽  
Jason Ingham
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Unreinforced Masonry ◽  
Brick Masonry ◽  
Seismic Events ◽  
Shake Table ◽  
Northridge Earthquake ◽  
Clay Brick ◽  
Seismic Capacity ◽  
Shake Table Testing

Past seismic events, such as the 1994 Northridge earthquake, the 2001 Nis-qually earthquake, and the 2010/2011 Canterbury earthquakes, have repeatedly served as reminders of the hazards posed by unreinforced masonry parapets. Observed failure modes have included several cases where adopted retrofit techniques were inadequate to effectively secure parapets during earthquake-induced shaking. In response, this paper investigates, by means of shake table testing, the dynamic behavior of nine clay-brick masonry parapets with commonly used bracing systems and alternative securing techniques, such as post-tensioning and combined braces and vertical strong-backs. Seismic capacity was improved 6 to 8 times compared to the as-built postcracked condition. The addition of vertical strong-backs further improved the performance of braced parapets, with capacity increased 12 times compared to as-built parapets. Parapet construction and retrofit procedures are presented, followed by a discussion of the developed failure modes as well as the response of the retrofitted parapets.

Seismic Performance of Chlorinated Polyvinyl Chloride Sprinkler Pipes

2018 ◽  
Vol 34 (3) ◽  
pp. 1497-1513 ◽  
Author(s):  
Jochen Carl ◽  
Zheng Peng ◽  
Harold Magistrale
Keyword(s):  
Numerical Simulations ◽  
Polyvinyl Chloride ◽  
Seismic Performance ◽  
Fire Protection ◽  
Bending Strength ◽  
National Fire Protection Association ◽  
Acceptable Level ◽  
Shake Table ◽  
Shake Table Tests ◽  
Pipe Bending

A major concern about chlorinated polyvinyl chloride (CPVC) pipes is the large swing of branch lines during earthquake-induced motions. National Fire Protection Association (NFPA) 13 defines spacing requirements for braces and restraints, based on pipe-bending strength, but does not limit the swing. Shake table tests and numerical simulations show that the swing of CPVC branch lines can be limited to an acceptable level if the ends are braced and the spacing of restraints follows the NFPA 13 requirements for CPVC, or if restraint spacing is reduced to about half of that currently allowed in NFPA 13.

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