Direct Answer
An anchor bolt template is a steel plate or wood jig drilled with holes matching the anchor bolt pattern for a column base plate. It is used during concrete pour to hold anchor bolts in their precise design locations while the concrete sets. Without a template, bolts shift under the weight of wet concrete and vibration, resulting in mislocated bolts that make base plate installation difficult or impossible.
Full Explanation
Template types: (1) Steel plate template — a piece of plate cut and drilled to the exact bolt pattern, temporarily bolted to the forming system above the foundation. Bolts are threaded through the template holes and secured with nuts; the template holds position during pour. (2) Wood jig — simpler and cheaper, often used for smaller projects. Less rigid than steel but adequate for small bolt patterns. Template precision: the bolt pattern hole tolerance is typically ±1/16" — this is the total error allowed between any two bolts in the group, not relative to the grid. Template fabrication should be done in the shop from the anchor bolt plan drawing, not laid out in the field.
What This Means for Your Shop
As a fabricator, you sometimes supply anchor bolt templates along with the bolts as part of the anchor bolt supply. If template fabrication is in your scope, treat the template's hole pattern with the same precision as a connection plate — use CNC drilling, not hand layout.
Common Mistakes
Reusing an anchor bolt template from a previous project without verifying it matches the current project's bolt pattern. Even one bolt in a different position creates a mislocated bolt condition that requires post-installed supplemental anchors.
Recommended Process
Drill anchor bolt templates from CNC files generated from the Tekla model anchor bolt plan. Verify the template hole pattern against the drawing before delivering it to the concrete contractor. Include a copy of the bolt pattern drawing with the template delivery.