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Re: Side Plate Systems - Eureka Moment[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: seaint(--nospam--at)seaint.org
- Subject: Re: Side Plate Systems - Eureka Moment
- From: Henry Gallart <hgallart(--nospam--at)sideplate.com>
- Date: Tue, 11 Dec 2001 12:50:18 -0800
>There are many good
choices for moment connections in special moment frames (and blast-resistant
construction) in steel.|
No engineer would dispute the fact that ductility in the design of a structure is an attribute when considering dynamic loading such as occurs during a seismic or terrorist event. Engineering logic does not, however, support the parallel presumption that if a connection system in a steel structure is beneficial in controlling seismic damage, it automatically is beneficial in controlling damage and preventing collapse during a terrorist
In fact, the majority of the connection systems for steel structures developed after the Northridge Earthquake are dependant upon building column integrity for collapse prevention. Several of the concepts developed and industry promoted, such as the reduced beam section connection ("dogbone" connection), are weakened by design in the critical column vicinity.
Before the surgically softened connection systems exhibiting "traditional" geometries are promoted for use in preventing progressive floor and building collapse mechanisms in steel frame buildings from developing, extensive testing must prudently be conducted to evaluate the extent to which the intentionally designed "fuses" used to limit connection stresses actually contribute to building collapse. Engineers interested in reading more about the behavior of steel frame connections subjected to blast loading are encouraged to access the following research presented at the recent National Symposium on Comprehensive Force Protection sponsored by the
Society of American Military Engineers (SAME) at The Citadel, Charleston, South Carolina, November 1-2, 2001
http://www.sideplate.com/reducedpresention_files/frame.htm(SAME Slide Presentation).
Another recently published paper by Weidlinger Associates, an internationally recognized blast engineering firm, presented at the 2001 Structures Congress in Washington D.C. last May, entitled "Behavior of Steel Structures Subjected to Blast Loading" also addresses the effect of connection geometry on steel frame behavior and concludes: "A ...philosophy in earthquake engineering is to place a fuse (weak component) in beams in order to ensure that these fuses would yield in a seismic event." ..."While this strategy may work for earthquake loading, it might induce failure in one of two possible manners during a blast event. First, when a direct blast load hits the beam, this weak link may lead to premature plastic hinging and member failure. Or, secondly, if the neighboring column is weakened, or destroyed, this beam may be required to carry even larger loading than it
was designed for initially. As before, this fuse would be detrimental in this situation. This latter situation is the more serious of the two, as it could cause the onset of a progressive collapse, resulting in widespread destruction of a building."
The SidePlate connection technology was conceived to develop the full structural strength of the adjoining floor and roof systems with or without the contribution of the supporting building columns. As such, the technology is the leading technical candidate to allow the safe use of steel framed building systems and to prevent progressive floor collapse in the present terrorist and blast prone environments.
Henry Gallart, S.E.
SidePlate Systems, Inc.
5300 Orange Ave, Suite 214
Cypress, CA 90630
- RE: Side Plate Systems - Eureka Moment
- From: Carter, Charlie
- RE: Side Plate Systems - Eureka Moment
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