After a thorough examination, based upon the ICC-ES report ESR-3330, the Hollo-Bolt® has gained the LARR approval from the City of Los Angeles Department of Building and Safety. The Los Angeles City Research Report provides a detailed evaluation of the Hollo-Bolt including its uses and performance. Although this is a state based review, it is of national importance to architects, builders and specifying engineers.
Following the LARR approval, contractors used over 3,000 Hollo-Bolts to
connect steel tubes which form the curved atrium on the Wilshire Grand Center building in LA.
Hollo-Bolts were installed from just one side, rapidly securing the
structure without the need for any onsite drilling or welding. The cost
effective installation did not require specialist equipment or
specialist labor. It also reduced the amount of work at height in
comparison to traditional welding or through-bolting methods.
Moreover,
the Hollo-Bolts allowed an aesthetically pleasing and discrete
connection method which complemented the design of the exposed steel.
The design eradicated the possibility of tube deformation that can be
associated with through-bolting if the bolts are over-tightened.

In addition to the LARR approval, the Hollo-Bolt is the only expansion bolt for structural steel which has a full seismic approval from ICC-ES for all seismic design categories (A through F).
Click here to download the Hollo-Bolt brochure.