1.The use of adhesive anchors for overhead applications has historically been limited. This has been based on the following considerations: a.fire b.creep c.difficulty of installation 2.All three of these subjects have been the subject of intensive investigation. Issues regarding use of adhesive anchors for overhead applications

Fire test facilities at the University of Braunschweig MPA/iBMB Fire

Anchor loading systems in burn chamber

Partial Comparison of ASTM E119, ISO 834 and DIN 4102 Time Temperature Requirements

Time-temperature curves for tunnels (Germany, Netherlands, ISO, EU) Time since start of fire [minutes] Temperature [°C]

TU Braunschweig Materialprüfanstalt für das Bauwesen (MPA)

Rupture of anchor steel

Failure of anchor threads

Results of testing to ISO 834 time-temperature curve Design resistances at 23°C: HDA M kN HDA M kN HDA M kN

1) Anchor was pulled out of the concrete 2) Anchor did not fail under full load after 140 minutes. Failure loads for adhesive anchor system used in conjunction with stainless steel thread rod Date of LoadsFailure testing anchor rod N rec. F actual F / N rec. Time (min) Failure mode (kN) M16 (stainless steel) bond 1) M20 (stainless steel)  140 none 2) bond 1)

thermal sensors to measure in-situ temperatures HY mm reinforcing bar C20/C30 concrete (min. 28-day strength, may be cored from existing specimens) Test Specimen 15 cm 25 cm heat source protect ends of specimen from heat source steel pipe

temperature (30 minute duration) [°C ] mean ultimate load [kN] Measured Residual Tension Capacity 250ºC (482ºF) mean cap'y at room temp. = 69.1 kN carbonization

Creep and installation

Sustained Load vs. Time to Failure tests at 43°C (110°F) with M12, h ef = 80 mm, mortar based on epoxy resin N u,Sust (10 years) ≈ 44 kN = 0,52 N u,m N u,m = 85 kN n = 2 n = 1 tests at N sust = 20 kN time to failure extrapolated according to ACI 355 n = 3 University of Stuttgart

Excerpted from Jack Breen’s presentation “For Want of a Fastener” at the 2007 Stuttgart Symposium on Connections between Steel and Concrete

NTSB Report HAR 07/02

NTSB Report HAR 07/02 p. 88

Improper injection can result in air voids within the borehole Air voids : Reduce bond surface Result in uneven stress distribution May increase susceptibility of bar to corrosion The pressure of injection pushes the piston plug out of the hole Reduces risk of air voids Prevents adhesive runout It is possible to achieve a void-free installation: piston plug extension tube hole adhesive

D.2 — Scope D.2.2 — This appendix applies to both cast-in anchors and post- installed anchors. Specialty inserts, through bolts, multiple anchors connected to a single steel plate at the embedded end of the anchors, adhesive and grouted anchors, and direct anchors such as powder or pneumatic actuated nails or bolts, are not included. Reinforcement used as part of the embedment shall be designed in accordance with other parts of this code. Adhesive anchors installed overhead to support sustained tension loads are not within the scope of Appendix D. RD.2.2 — The wide variety of shapes and configurations of specialty inserts makes it difficult to prescribe generalized tests and design equations for many insert types. Hence, they have been excluded from the scope of Appendix D. Adhesive anchors are widely used and can perform ade­ quately. At this time, however, such anchors are outside the scope of this appendix. The use of adhesive anchors installed overhead to support permanent loads is associated with several factors that may significantly impact the tension resistance. These include fire safety, installation quality and creep behavior. Pending the conclusion of studies into these areas, the use of adhesive anchors in this condition is excluded from the scope of this appendix.