VERTEX was selected as the Structural Engineering design consultant for the new TSA area of the Jackson Hole Airport in Jackson, Montana with Jvation Inc. The 10,000 sqft area of the existing terminal is to be demolished and replaced with new structure. The lateral system will reuse existing CMU, existing concrete shear walls, and a new concrete shear wall. The roof framing consists of exposed glulam beams and steel trusses spanning 100′ over the space. The area to the west will be cladded with glass curtain walls to accentuate the view of the mountains to the west.
Scope of Work
VERTEX had the opportunity to work with the architecture firm Jviation Inc. on the demolition and construction of the new TSA and “hold room” areas of the Jackson Hole Airport. The existing building was built in the late seventies and the airport would like to introduce a more open concept to highlight the views to the west of the Teton Mountains.
The new TSA/Hold room will be 100’ x 125’. The airport wanted to clear span the 100’ dimension. The most viable structure to do this in our minds was a steel truss. We needed to limit the amount of web members in the trusses to increase the viewing area. The roof support between the trusses was made to match the other existing construction within the airport. The airport utilized glulam beams (GLB) with a steel tension rod to increase the spans the GLB could span without having large deflections.
The steel truss we designed had a depth of 6’-6” to increase the perceived head height of the area with four web bays for the open feel the airport was looking for. The design for the truss was completed utilizing RISA 3-D. To limit the number of miscellaneous members the bottom chord of the truss was designed to span the full 100’ span without braces. The most economical design for the bottom chord was to rotate the bottom chord so the major axis was horizontal. This allowed the bottom chord to span the 100’ in tension while implementing a 5 psf interior wind load on the faces of the truss. The bottom chord is a W12x87 and the top chord of the truss is a W21x132. These sizes reduced the deflection of the truss to 1 ¾” so a sag would not be observable over such a large span.
The joists of the roof structure matched the GLB seen in the other parts of the building. The GLB were 21” deep and 5 1/8” wide. Custom joist hanger buckets were designed to hang off the top chord of the trusses. This gave the Architect the ability to paint the buckets the same color as the trusses. The ceiling of the area will be a tongue and groove wood plank. The ceiling plenum area was only 1’-2” deep. Most of the mechanical HVAC work was done below the slab on grade. The fire sprinklers had to be run just below the ceiling. Web openings were provided through the top chords of the trusses. Areas of the GLB joists were laid out for the Contractor where a 2” hole could be cut into the member without needing to reinforce the joists.
The existing lateral resistance system of the building is going to be reused. Concrete walls in the west and east side of the site and a CMU wall on the south side of the site will be reused. A new concrete wall was placed on the north side of the site to replace a wood sheathed shear wall. The building is located in a high seismic area which implements provisions that post installed anchors need to have the controlling failure be in the steel of the anchor. This caused the drag struts from our new structure into the existing concrete wall to consist of eleven 5/8”Ø through bolts with a spacing of 10”.
When the project is finished the TSA area will have 3 lanes of screening and will have the ability to expand to 5 lanes of screening. The west wall of the hold area will be glass storefront and will give the visitors to the airport a 180-degree view of the Teton Mountains. The project is scheduled to be completed in the summer of 2022. The airport will close for a month during the construction for the tarmac to be repaved. The invasive work of this project will be done during that time.