IN THE FIELD
By Jeremy Ratledge
New Solutions to Old Problems Testing new rigging method for placing joists
A new type of remote-release hook provides an alternative to the use of open hooks for placing panelized joists.
P
anelizing joists for placement is one of three common methods for landing joists on a structure. The benefit is that fewer lifts are required by the crane, increasing its productivity for other tasks. In addition, panelized joists only need to be secured at the four corners before releasing from the crane, making it an efficient construction method. Piedmont Structural uses an engineered rigging frame to pick up panelized joists, which provides stability for lifting. The joists attach to the frame using specially designed open hooks that are inserted into the open webs of the joist. Slings connect the frame to the crane hook. Once ironworkers have positioned and secured the joist bay, the crane operator can then lower the rigging frame and guide the hooks out of the open web joist members and return the frame to the ground for the next lift. To release the hooks, traditionally, the ironworkers either have to walk out to the rigging or position themselves under the joists
working from an aerial work platform. However, we are increasingly encountering General Contractors that are not comfortable with the use of open hooks, despite the other benefits. After learning about a new type of remote-release hook at the recent SEAA Convention & Trade Show, we asked the supplier to demonstrate how these hooks might enable us to continue to use the panelized method with our custom lifting frame. We invited two other SEAA member companies— Mabe Steel Inc., Kernersville, N.C., and CAS Steel Erectors, Inc., Hendersonville, N.C., to watch the demonstration.
Remote release hooks
OTH Pioneer Rigging, Montreal, Quebec, offers two models. LudwigHook has a 4,400 lb working load limit. It is mostly used for setting joists, purlins, and girders. The LudwigHook XL has a 11,600 lb working load limit, enabling it to lift heavier components such as beams and columns. The smaller hook weighs just 6.2 lbs, while the XL weighs 15 lbs. The hooks are controlled by a radio remote control up to 200 ft away, and can be Jeremy Ratledge is a Project Manager for used in combination to achieve scalable Piedmont Structural Co., Salisbury, N.C. lifting capacity. Hooks can be released 26 | THE STEEL ERECTORS ASSOCIATION OF AMERICA
Below the rigging frame, the Ludgwig hooks connect directly to the lifting beam. The joist is connected using a basket hitch from the Ludwig hook.
