Detailing the process of engineered rigging

When it comes to a heavy lifting project, be it at a construction site, industrial plant or bridge build, there is much at stake. The safety of the crew, the value of the load, the project schedule and budget are just a few of the considerations that must be safeguarded.

The expertise of an engineering team and a proper lift plan are essential to mitigating the risks that are inherent in every project. Well in advance of moving any massive item, engineers must account for numerous factors when creating a lift plan including the equipment, technology, labor, site constraints, safety, local regulations and more. Using careful analysis and computer simulations, an engineering plan identifies every minute detail of the lifting project.

A copious engineering process provided a clear plan, from concept to completion, on a project that involved removing and replacing two 65-ton feedwater heaters at a nuclear station. See the boxed story at the end of the page for the full job description.

Investing the time to systematically consider and plan for every element of a project helps prevent costly errors and downtime. In addition, the engineering plan ensures that all personnel involved understand their role, project budget and schedule – while simultaneously optimizing site safety. The planning process also enhances communication among the numerous stakeholders which often results in synergies and efficiencies.

“By bringing everyone together in the infancy of a project, you dedicate time to explore and analyze every facet of the lift,” said Christopher Cox, PE, co-founder and president of Engineered Rigging. “It’s during this collaborative period that creative problem-solving occurs and cost savings and synergies are discovered.”

Engineering is the lens by which we look at the details to determine if a project can be done safely and in a cost-effective way. While most consider an engineering team to be the school-trained engineers, it is becoming more popular to think of project engineering as the larger team of project manager, field personnel and engineering, which allows for many perspectives to shape the engineering solution. Although project scopes have become larger and technology enables one to say yes to almost any size of lift, it is up to the engineering team to create a solution that falls within the realm of possible and also within budget.

Equipment decisions

When considering a project, most companies approach it with a goal of utilizing existing equipment. The benefit of using existing equipment is that the physical parameters are well-established. In general, when existing equipment can be used, the job is more economically feasible. Models of equipment in 3D CAD format, load charts and other engineering data are compiled to make it easier and more efficient to put these tools to work. The less hours that are spent on recreating a solution, the more can be spent on details, project parameters and thinking through load cases.

In many cases, the existing equipment will not be enough to fit all aspects of a job. Innovative engineering teams will provide a healthy mix of standard tools with a blend of custom action accessories to solve an application challenge. In many cases placing an engineering team near either an “in-house” fabrication capability or a close external source allows for quick decisions on what type of custom product is feasible to add without potential for outrageous cost adders.

Of course, just because it can be done doesn’t mean it should. Most engineers, given enough time, can design tools to work for the job. The goal of the engineering team, which may include engineers and non-engineers alike, is to come up with a safe, efficient and cost-effective way to solve a problem. The challenge to the engineering team during all phases is to simplify the problem into smaller blocks and utilize tools and experience to effectively predict the details needed to overcome variables present on lift day. Utilizing tools such as SOLIDWORKS and Autodesk Inventor allows the engineers to replicate the workspace and use that as a solid visual handout to define, and later refine, a solution.

Leveraging technology

Computer drafting in 2D and modeling in 3D allows the expansion of the engineering team to project managers, site superintendents and technicians who add valuable input to the process. Additionally, on occasion these models will be further refined in 3Ds Max and other applications to create a fully modeled video of the lift over time.

These models can create confidence in a project team when new technologies are developed or existing technology is used in a non-standard way.

To draft a concept for a particular application, engineers use modeling software to create a form/fit/function solution all the while checking basic calculations on the gear in the background, using programs such as Mathcad, RISA and even Excel. Likely, a well-worn copy of the Machinist’s Handbook is nearby.

FEA software built into the 3D modeling software is often used as a quick check on stresses, verifying that a component being used for a lift such as a beam, lifting eye or perhaps something more custom is up to the other demands of the application. This FEA work, while strongly indicative of the go/no go of project stresses using highly visual color coding, is subject to the experience of the engineer involved and, in most cases, followed by engineering calculations documented in Mathcad or another calculation program. The engineer, using the tools available in his toolbox, evaluates suitable load conditions removing doubt as to the validity of the engineered project solutions.

Once a solution is developed, it is again reviewed by the cross-functional engineering team for feasibility. The last thing the project team wants at this point is a solution that requires the last bit of “unobtanium” left on the planet or a large order of metric T1 plate. A practical hat is put on for these occasions during which a trained eye changes sizes in drawing for those more readily available or perhaps in line with existing equipment in the yard. The more equipment that can be repurposed, the more economical the outcome.

Before a plan can be implemented, the structural plans and processes need to be carefully reviewed. Load tests need to be conducted to ensure the selected equipment will operate as intended. In addition, feasibility and video simulations are often run to ensure that the plan can be safely executed and unexpected surprises can be avoided.

On site, several steps must occur before the lift begins. All involved need to carefully review the detailed plan, verify equipment functionality and component integrity and vet procedures.

By investing the time to develop, test and implement a detailed engineering plan, risks can be mitigated, deadlines can be met, safety can be optimized and cost savings can be realized. The return on investment is immense.