Simpson THD concrete screw

A relatively new product in the market, the large diameter concrete screw goes by many different names: LDT (Large Diameter Tapcon), wedge bolt (not to be confused with the wedge anchor), Screw Bolt, Titen HD or THD Anchor, Power Skru, and screw anchor, are just a few of the generic and brand names used for this product.

The variety of names are mostly a result of the many manufacturers that make them, but all of these names refer to a large (3/8” to ¾” diameter) concrete screw with a hex head (some sizes are also offered in a flat head), available in galvanized, stainless, or most commonly, zinc.

uses for concrete screw
Suitable for use in place of code anchor bolts.

Atlantic Bolt carries Simpson Strong-Tie brand Titen HD anchors in stock but we can get other brands. We can also provide information for various manufacturers’ specifications and sizes. Contact us at 704-597-5082 or [email protected] if you have any questions about this anchor or any other products.  

The large diameter concrete screw’s is becoming more and more popular because, depending on project and engineer specifications, it is an alternative for cast in place anchor bolts, expansion anchors, and epoxy/adhesive anchors. In addition, the hex washer head makes for easy installation and provides a more finished appearance after installation. Also, many brands are qualified for static and seismic loading conditions as well as cracked or un-cracked concrete. 

Another advantage is that the anchor is removable, making it ideal for temporary anchoring (e.g., formwork, bracing) or applications where fixtures may need to be moved. (Note: in a removal and replacement situation reuse of the same anchor to achieve listed load values is not recommended.)

Here are some applications that these anchors can be used in:

General Construction

  • -Light Frame Construction
  • -Ledgers
  • -Postbases
  • -Hold-downs
  • -Decks
  • -Railings

Retrofit and Repair

  • -Seismic retrofit
  • -Architectural attachments
  • -Concrete Formwork
  • -Concrete removal

WWTP/Water Treatment

  1. Pipe support
  2. Gates
  3. Pump attachment
  4. Handrails


  • -Conveyors
  • -Rollers
  • -Stadium Seating
  • -Awnings
  • -Steel beams/Columns
  • -Dock Doors
  • -Bumpers
  • -Exterior Stairs/Ladders
  • -Ornamental Iron
  • -Protective Railing
  • -Fencing
  • -Security Cage
  • -Shelving
  • -Racking
  • -Tilt bracing

Cold Form Steel

  • -Wall braces
  • -Masonry ledgers
  • -Interior bases/ceiling track
  • -Hold-downs

See the video below from Simpson Strong-Tie for more information on this versatile anchor.