Typical precast concrete sandwich panel (PCSP) systems are composed oftwo concrete wythes with insulation placed in the center. The concrete wythes are generally connected through the insulation using metal, concrete, thermoplastic or glass fiber reinforced polymer (GFRP) connectors. PCSP systems canbe designed to be composite or non-composite structural members. In non-composite walls, one wythe is counted onto resist the entire applied loading, and the second wythe is considered to be non-structural. In composite construction, the two concrete wythes share the load resistance through the connector that is capable of resisting the interface shear force resulting from composite action. Precast concrete sandwich wall panels can be classified as:

Aslan 700 Nu-Tie Sandwich Wall Connector Features:

• Aslan 100 GFRP rebar connector Truss Elements
• Plane truss which is easy to place in Expanded Poly-Styrene Foam Slots
• Tested and Proven System
• Patented system available to users of the Aslan 700 Nu-Tie system
• No reason to join a "club" or pay a royalty to use the patented system as the licensure is built directly into the cost of the Aslan 700 Nu-Tie

Available for Wall Panels with 2", 3" & 4" (50, 75, 100 mm) EPS Insulation

Tests were conducted to evaluate the performance of the panels with differing amounts of transverse reinforcing. It was found that transverse reinforcement had practically no effect on the capacity of behavior of the panels, as long as a minimal amount of #3 (10 mm) reinforcing at 32? (812 mm) centers is provided.

The ultimate structural capacity of tested wall specimens using the Aslan 700 Nu-Tie is approximately 150 psf (7.2 kPa) loading on a 32ft (9.75 m) tall wall, compared to 25psf (1.2 kPa) typically assumed for design.

A key part of this system is a fixture that hot melts slots into the foam blanks. Hughes Brothers will work with the precast company to supply a copy of this machine or provide drawings and detailed parts lists that would enable the precaster to fabricate their own machine. On site, the precaster will likely need to add exhaust containment hoods and adequate ventilation to deal with smoke and fumes associated with the melting of slots in the foam. Material Safety Data Sheets and EPS foam supplier information assure this smoke is non-hazardous and non-toxic, but certainly not a pleasant odor and as such should be adequately vented.

 

After hot melting slots in foam blanks, the appropriate Nu-Tie for the foam thickness is easily inserted into the blanks.

 

Remaining gaps are simply filled with canned expanding foam insulation available from several local sources. Excess foam is easily removed with a long, flat fine tooth blade. The Aslan 700 Nu-Tie ends should rest against the face of the EPS foam ensuring proper exposure and penetration into the concrete wythe on either face of the foam.

Aslan 700 Nu-Tie Precast Production

Once the casting bed is prepared, the bottom wythe strands stressed and any transverse reinforcing in place, concrete is placed in the bottom wythe. Typically, SCC (self consolidating concrete) is used. Prepared EPS foam blanks with Nu-Ties now integrated into the foam blanks are simply placed on the first concrete wythe.

At this point, any block-outs, window or door openings can be accommodated in the prepared EPS foam blanks by simply cutting them to fit.

The second wythe of concrete is ready to be placed over the EPS foam once strands are stressed and transverse reinforcing put in place.

Ordering Information
The Aslan 700 Nu-Tie is configured for 2", 3" & 4" (50, 75 & 100 mm) foam insulating panels. As such, there are only three items to order and stock: