Can you site bend Grade 8.8 M16 HDG threaded rod? If so what is the maximum limit of bend? Percentage of rods for a base plate have been installed on an angle and base plate won't fit. Holes were drilled to avoid existing Reinforcement.
I am aware this question is quite old, and has been responded to, but the answer provided by hilti is absolutely wrong. Grade 8.8 bolts are quenched and tempered steel, not mild steel, and will not bend any significant amount without causing fracture.
Hello Craig,
Thank you for reaching out to Hilti.
On-Site Bending
- AISC states you can cold bend mild steel up to 45 degrees for bolts less than 1 inch diameter.
- ASTM F1554 permits both cold and hot bending of anchor rods to form hooks
However, bending in the threaded area can be a problem. It is recommended that only Grade 36 rods be bent in the field and the bend limited to 45° or less. Also, rods up to about 1” in diameter can be cold bent and after bending, the rods should be visually inspected for cracks. Hence, field bending of Grade 8.8 HDG is acceptable as long as it is not more than 45°. If the bend is more than 45°, the project/design engineer should be consulted in order to make the proper engineering judgment.
After straightening, if there is concern about the tensile strength of the anchor rod, the rod can be load tested. In all bending/re-bending operations, surface damage must be avoided. Impact blows, such as by a sledge hammer, or power tools, to assist bending, should also be avoided as this may result in an uncontrolled bend diameter being produced, or the surface may be notched and damaged during clean out of the concrete, and cause the steel to display reduced bend ductility. Where possible, a purpose-made power tool should be used for straightening and re-bending.
Inclined Anchor Install
In general, if an anchor is installed at an angle greater than 6 degrees from perpendicular to the concrete surface, there are some important items that need to be evaluated from an installation, capacity, and load application perspective:
- A tension-only load applied on an anchor that is installed at an angle will have a tension and shear load applied to the anchorage due to the angle. The designer should take the tension load and translate this to the tension and shear load based on the actual angle of the anchorage.
- An anchor installed at an angle will tend to have a reduced embedment depth than designed. The effective embedment depth (hef) should be reduced to reflect the distance from the end of the anchor (or to the effective embedment mechanism for expansion anchors) normal to the concrete surface. This will reduce the design concrete strength and bond strength capacity
Hope this helps.
Kind Regards,
Ask Hilti Team
Australia