Direct Tension Indicators (DTI)

ELC Technologies has reinvented the Direct Tension Indicator. We use a uniquely patented protrusion design to improve upon the original DTI that has been around for over 50 years. The DTI is a “mechanical load cell” with bumps or protrusions stamped out on one side. As the bolt is tensioned, NOT torqued, the protrusions will push back and are inspected by the use of a feeler gauge to determine that the bolt or stud has been properly tensioned.

DTIs are being used by many departments of transportation to indicate the proper tensioning of structural fastener assemblies in steel bridgework and other steel structures. Engineers can visually inspect bolts for proper tension in slip-critical or fully pre-tensioned bolted connections. DTIs used by state highway departments in steel bridgework are manufactured to ASTM F959 Standards, and are available in an assortment of finishes.

DTI/Nut Assembly (DNA)

ELC Technologies has incorporated the standard DTI with a nut to create the DNA (DTI/Nut Assembly). This product has been approved by AASHTO for use on bridges.

DTI/Bolt Assembly (DBA)

ELC Technologies has also incorporated the standard DTI with a bolt for a product called the DBA (DTI/Bolt Assembly)

These unique products along with the standard DTIs are revolutionizing the fastener industry and the way things are bolted together. Not only are these new to the market, but most of all are user friendly. These assemblies ensure that the DTI is orientated in the correct direction and reduces the number of parts that needs to be handled. This increases productivity while eliminating errors. When using a DNA or DBA by ELC Technologies you will have complete satisfaction that your bolted connections are properly tensioned.

Patent Pending


Look for our ELC logo as your assurance of quality for our products and engineering services for customized direct tension indicating components, assemblies, and applications: