Safety Important to the Growing Tilt-Up Industry
By: Jim Baty, Tilt-Up Concrete Association. He can be reached at jbaty@tilt-up.org.
Tilt-Up construction continues to lead in growth as a wide-spread building solution due to its advantages of efficiency, economy and effectiveness. In fact, Tilt-Up construction has grown at an annual volume of more than a quarter billion square feet of wall, outperforming the general building industry during the past decade. Market growth, however, means that people are entering this field at a rapid rate, requiring increased attention to safety — another long recognized benefit of Tilt-Up.
Yet while gaining an understanding of safe Tilt-Up practices may be especially important for a newcomer to the industry, veterans should habitually review safety guidelines. After all, lifting 8-inch-thick load-bearing concrete wall panels weighing 60,000 pounds or more and measuring 30 feet wide and 50 feet tall requires no margin for errors, especially when it comes to safety.
Despite the obvious safety considerations of erecting massive concrete wall panels with large mobile cranes, Tilt-Up construction offers great safety for crews. Since the floor slab is cast first as it is the primary casting surface for the wall panels, a solid dry work area is created for the building trades. In addition, constructing the framework on the ground eliminates the need for scaffolding, further increasing worker safety. Overall, site-cast Tilt-Up construction is recognized as a reliable and safe building method, if utilized in conjunction with good planning and a solid safety program.
BEFORE A PROJECT BEGINS
For Tilt-Up crews to take advantage of the benefits of speed and economy inherent in the site-cast Tilt-Up process, safety programs and guidelines must be enforced. Since a comprehensive safety program goes well beyond what to do and not do in the field, it must begin in the office before any workers even go to the field. For example, your safety program should include a review of all subcontractors, contracts and purchase orders – allowing you to address safety concerns and attribute responsibilities. Further, ongoing training is essential, which necessitates actually bringing the training to the crews in the field.
DESIGN AND TESTING CONSIDERATIONS
In addition to the management planning, analysis and awareness training, safety should be addressed in the design and testing process. Key considerations for review between the design and construction team include the following:
- Alleviating tripping concerns: Since panels contain much reinforcing, ensure no protrusions exist that may impale a worker who stumbles.
- Proper installation of lifting hardware and inserts: Ensure these products are tested and verified for performance.
- Concrete strength key: Ensure the concrete strength is tested for field, not merely lab, strength. Also make sure the floor slab has been properly designed for the brace load.
During the design phase, another important safety consideration is the floor slab and its load capacity. If the lot size or other factors require that the panel erection be completed on the floor slab, careful consideration and planning should be undertaken to ensure that the floor slab thickness and reinforcement can withstand the weight of the panel and crane. Furthermore, it is imperative to consider the concentrated weight on a crane’s outrigger or track during panel raises. If erection stress — the weight concentration effect on a floor slab — it is not taken into consideration, the result is usually a cracked or broken floor slab.
The crucial decision as to whether or not the crane will erect the panels from the floor slab or the perimeter also affects the project plan.
Although perimeter erections can cost more than an on-slab erection, they often present a great advantage in terms of reducing risks to the floor slab during the panel lift process. As such, it is important to advise the owner of the pros and cons of on- slab versus off-slab panel lifts.
COORDINATION OF PERSONNEL
A significant contribution to a safe Tilt-Up construction site is the coordination of personnel. When a site is cluttered with people who are not actively and intelligently working, accidents are more likely to happen. For this reason, it is appropriate for construction crews to have a pre-tilt walk-through and safety meeting. This serves to identify potential job site hazards, to assign each individual a specified task(s) and to review pertinent on-site safety issues.
Prior to the erection day, many also recommend a safety meeting that everyone who will be at the jobsite attends. At the meeting, all crew-members should sign a safety checklist for documentation of the meeting. Review the lifting safety checklist provided by the Tilt-Up Concrete Association (TCA) and address all concerns such as proper attire, how to look out for other crew-members and where to stand during the lift.
ON THE JOBSITE
Once it’s time for the erection process to begin, another important safety consideration is the crane. According to the TCA, the crane should be able to lift the heaviest panel plus the weight of the rigging gear. Therefore, when selecting the crane, it is important to consider how far it must reach and if it will have to travel with the panel.
Other considerations include location of equipment, overhead wires, underground lines and soil conditions – all factors for the crane operator. Crane operators should do a dry run of the lift under the supervision of the superintendent to check for any obstructions that might hinder the lift process. Furthermore, only one person should be identified as the ‘rigger’ — the designated person who provides the directional signals to the crane operator. All hand signals between the ‘rigger’ and the crane operator must be identified before the lift.
Safety at the Tilt-Up site does not end after panel erection. In fact, proper bracing is an important safety element. Prior to construction, a bracing manual with braces designed for the proper wind conditions should be obtained. The braces should be examined for any damages and should meet all manufacture requirements. After the lift, all brace inserts should be checked at the beginning and end of each workday to ensure that they are tight. Further, braces should not be removed until the engineer of record has given written consent. A competent team of two people should perform a daily inspection (including holidays). If possible, grout under all erected panels at the end of the day.
Once the project is completed, the safety process should continue. According to Ed Sauter, executive director of TCA, accidents tend to happen when workers become complacent or comfortable with a process and therefore skip steps. He recommends that even the most experienced Tilt-Up crews continue their education and refine their techniques through seminars and networking opportunities. The TCA offers several resources in this category, including seminars and published resource materials. For more information, visit www.tilt-up.org or call 319-895-6911.
