Mon, 08 Feb 2010 22:06:06 +0000

< Yes you could do the job with a 200amp set but it probably wouldn't last very long as you would be running at or around its limit. As you have 3phase think about second hand, for less than a grand I would think you could get a much more powerful set. Lincoln, Hobart, Miller, L-Tec all American and fairly bullet proof, Migatronic, Butters,Oxford, Murex, Cebora, European. Mta, Portamig made in U.K to name a few. Go for a bigger set than you think you need, its better to have a big set cruising than a small set being flogged.

2010 EEA State Gold Award Winner – Reid Middleton’s Alaska Air Seismic Upgrade

Gold Award – Exceeding Client/Owner Needs

Reid Middleton, Inc. – Alaska Airlines Maintenance & Engineering Building Seismic Upgrade

Client: Alaska Airlines

Alaska Airlines’ SeaTac-based maintenance facility is critical to the airline’s regional and national 24/7 operations.  Crews use the facility to maintain and repair the airline’s aircraft fleet so departures around the nation are not delayed.  After the February 28, 2001 Nisqually Earthquake, the airline commissioned a seismic screening and evaluation study of the facility to ensure that the building would remain functional after the next major earthquake.  A seismic upgrade was the ultimate solution, and Reid Middleton was brought on board to provide structural engineering expertise.  In addition, the design and construction team was to be constrained by the requirement that the facility remain open and functional throughout the upgrade.

Typically, during an earthquake, the energy generated in a building is dissipated through the yielding of braced or moment frames, or the yielding of reinforced steel in shear walls.  But these methods of dissipating energy can cause significant damage to structures.  So Reid Middleton designed a system using state-of-the-art energy-dissipating seismic friction dampers – a series of plates tightly clamped together that absorb earthquake energy by rubbing together and generating heat, much like the brakes on a car dissipate energy in the form of heat.  The dampers allow a building to move only in specific locations, dissipating energy through friction in the damper rather than damaging the rest of the building.   This approach extends the useful life and reduces the overall life-cycle costs of the building, and reduces the demand for natural resources that would be required to build new structures.

Reid Middleton installed 56 friction dampers at 28 strategic locations throughout the building.  Where dampers were installed at existing braced frame locations, they could quickly and easily be installed without modifications to the existing gusset plate connections or foundations, allowing the contractor to move quickly in and out of spaces and minimizing the interruption to the building occupants.

Few structures today contain friction dampers, so the Alaska Airlines maintenance facility’s seismic upgrade will provide important information in future earthquakes since building displacements can easily be measured from paint scratches that result when friction dampers rub together.