Cost Analysis
To the owner of a project, DTI's will cost either nothing, very little extra, or possibly will result in a small saving. This is why we (and others) say that the "total installed cost", or TIC, of DTI's, is negligible. In fact, in a total cost comparison with turn-of-nut, Florida DOT measured a savings of about one dollar per bolt when their contractor used SQUIRTER® DTIs! view the Florida DOT study
The true cost effect of DTI's is influenced by a number of factors: the efficiency of workers, type of connections, degree of inspection, type of work either light or heavy, whether the steel members are ground set or set from the air, the source of the DTI's, size of project, and whether the project is a bridge, a simple building, a more complex building, a large or small power plant, or a very slender and light special purpose steel frame. Bolting installation labor cost is affected by the type of bolt, either hex head or twist-off, and of course the associated inspection labor cost is also interrelated to the selection of bolt type.
The tables of cost data look at several scenarios which are representative of light, medium, and heavy types of steel construction, and assumes there are DTI's on EVERY bolt. Readers of this data will be able to adjust the individual entries to reflect their own situation of course. For instance, loaded labor rates around the USA will vary from half the $50.00/man-hour used below to more than $100.00/man-hour in some situations.
During an independent study, in conjuction with Keith and Schnars and Wood Hopkins Erectors, the FLDOT have used SQUIRTER® DTIs on the Beaver Street Bridge Project, and compared them to Turn-of-Nut. SQUIRTER® DTIs came out FAR ahead, according to the study trial.
The trial highlights include;
- a dollar a bolt savings on installation (!!)
- 75% time savings for aerial bolting (!!)
- less installer fatigue
- immediate verification of bolt tension
- and less than 1% retighten work required
Check out the trial results for yourself in pdf format, as written by Keith and Schnars for the Florida DOT. Go to the trial results here