IN THE FIELD - New Solutions to Old Problems

By Jeremy Ratledge

Testing new rigging method for placing joists

Panelizing 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

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.

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 used in combination to achieve scalable lifting capacity. Hooks can be released one by one or all at once. In addition, they can be used with any type of sling in choker, vertical, or basket hitch configurations.

To test this new tool, OTH Pioneer Rigging sent us 10 of the 4,400 lb WLL hooks. We prepped a panelized bay of five joists at our office in a configuration similar to what we use in the field. Ten slings in vertical hitches attach to the top of the rigging frame. These slings connect to a single lifting point at the crane hook. 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.

The response? This was awesome! Workers on the ground can prep the joists for hoisting in a few seconds. Once the panel is in place and secured by bolted connections or welds, a simple push of two buttons released all 10 Ludwig hooks at once.

It has always been our belief that any task that can be performed on the ground prior to the lift reduces risk for the ironworkers in the air. Using these hooks permits the bay of panelized joists to be erected without an ironworker walking out to release them, and reduces the possibility of “pinch points and crushed by” resulting from ironworkers positioning themselves in a boom lift platform between each joist to release rigging—an activity that can take place as much as 100 times per day. It also speeds up production by eliminating open hooks from becoming entangled in bridging and joist members, and it satisfies the general contractors who are looking to eliminate open hooks on job sites. •

THE CONTRADICTIONS OF OPEN HOOKS

By Tracy Bennett

Joe Kuzar, Technical Director for Industrial Training International, Woodland, Wash., offers these reminders when it comes to rigging with open hooks and using custom below-the-hook lifting devices. “There are a lot of contradictions in the standards regarding the use of open hooks,” he said.

“For steel erection, Subpart R is silent on this, but ASME B30.5-1.7.6 states “hooks shall be equipped with latches unless the application makes the use of a latch impractical, and ASME B30.10-1.11.1(m) states “the need for a latch or mousing on any hook is a function of the application of the hook and shall be determined by a qualified person.” Meanwhile, according 29 CFR 1926.1425(c) (2): “Hooks with self-closing latches or their equivalent must be used. Exception: “J” hooks are permitted to be used for setting wooden trusses.”

If using open hooks, he recommends writing procedures that specifically identify the hazards that are created by using closed hooks, and how the use of open hooks mitigates that.

“As a former crane operator, I like the idea of lifting panelized joists,” he added, as it means making fewer lifts. When using any below-the-hook lifting devices, the standards call for the device to be properly labeled with the manufacturer name, serial number, rated load, ASME design criteria and design class. Custom made devices must be designed according to ASME BTH-1 by a qualified person.

When using a new tool with which safety personnel may not be familiar, Kuzar suggests providing documentation on site that guides operational procedures, recovery plans for worst-case scenarios, removal from service criteria, and even the standard- to which the below-the-hook lifting device was designed. “I always recommend putting your people in a position to be able to defend their rigging decisions,” he said. And with new technology, such as a remote-release hook, or a custom engineered lifting device such as a joist frame, “It’s all about educating people so that they understand the proper procedures,” he said.

Jeremy Ratledge is a Project Manager forPiedmont Structural Co., Salisbury, N.C.