McGraw Hill Construction, the Lean Construction Institute and Dassault Systèmes teamed up recently to produce an in-depth report on Lean Construction. Below is a case study from the report:

Planning and Coordinating Prefabrication to Increase Project Profitability

St. Elizabeth Hospital 5-Story Patient Tower and Connector Building in Appleton, Wisconsin

The Boldt Company has been using Lean project delivery for over a decade, and they have been able to bring many of the lessons they learned from the industrial side of their business to bear on their general building projects, according to Will Lichtig, vice president of business and process development at Boldt.

As general contractors who self-perform many trades and work collaboratively with trade partners on others, prefabrication is one area where they have been able to find opportunities to improve cost, schedule and safety on their projects while sustaining or improving quality.

Planning Approach Critical for Effective Prefabrication Use

Lichtig reveals that there are two factors that contribute to their success with intensive coordination of prefabrication on their projects: a disciplined planning process and an integrated approach to project delivery.

He clarified that for each project, they first need to determine what level and kind of prefabrication makes sense.

Being part of an integrated design process allows them to influence decisions during design.

Lichtig reports that they use an A3 process to make sure that “when you are evaluating prefabrication as an option, you are doing all the necessary research…rather than looking at assumptions or what may have happened on the last project, to try to make sound decisions.”

Part of that decision-making process is looking at the supply chain.

The transportation of prefabricated items can impact schedule and quality, and they look at each individual element across the critical factors of schedule, safety, cost and quality in order to make their decision to use prefabrication and the degree to which it was useful.

For example, in a project they conducted in Moose Jaw, Canada, schedule became an important factor in the decision to prefabricate elements of the exterior enclosure of the building, because if the building was not enclosed before winter started, that would have significant implications for the remainder of that schedule.  Instead, that final element was installed onsite.

They use a similarly rigorous process on all their prefabrication decisions.

Impact of Logistics on the Selection of Trade Partners

For the fourth and final phase of the expansion of St. Elizabeth’s hospital in Appleton, WI, they knew from the start that they would be looking at the gains they could obtain from prefabrication because the owner of the project challenged them specifically to see what they could accomplish by taking this approach.

However, through prototypes and first-run studies, they also determined that the insulated metal panels that make up the skin of the building should not be included in the prefabricated components because they could not get the right seal in the shop during that process, increasing the risk to the quality of the project.

As Chris Waldron, field engineer and project engineer for Boldt on this project explains, this allowed them to explore options that they had not done on other projects, and it had an impact on their selection of the project team.

Waldron states: “[Their prefabrication capacity] was part of what we evaluated [the trade contractors] on. Who’s pushing the envelope, in addition to things like price. We took tours of their shop to see how Lean their operations are, and their production facilities for doing this work also went into the evaluation.”

Trade firms were also asked whether any had space that they could dedicate to additional prefabrication work should opportunities arise “to take it to the next level,” and the plumber they selected offered that opportunity, one which they are already taking advantage of.

Tackling Logistical Challenges

As with their other projects, intensive planning was critical.

Waldron describes how they conducted first-run time studies for each of the prefabricated elements, but they also made sure to include all the logistics of transportation as well, from how they get components on the truck to the bridges they need to clear.

“We tested the build, we tested the delivery, and then we were able to either confirm or adjust our anticipated production.”

Included in those calculations is an anticipated performance factor that comes from doing this work repetitively, which shortens the schedule.

Waldron also describes taking into account challenges that occur onsite and using the planning process as an opportunity to develop creative solutions:

“We are making these headwalls ahead of time, and we had to figure out a way to get them on to the site [without damaging them.] So we thought about a way that accounted for corridor width and above-ceiling clearances. As a group, we came up with a sketch. We got buy-ins from everybody. Now we have this cart that we can put our headwalls on and can pick up with a forklift or a crane. We built one to see if it would work, and sure enough, it did.”

Lichtig mentions that they are seeking opportunities to utilize this cart on other projects in Wisconsin. Gaining buy-in from the foremen was a key part of this process, and it was a critical part of their overall process as well.

They used the feedback from these workers to conduct a complete value stream analysis of both the traditional stick built conditions and the use of prefabrication.

The process is intensive and attempts to capture all elements, such as the time needed to pick up scrap cutoffs and to go up and down stairs.

The results of that process for two prefabricated components are featured in the table on the right.

Getting worker feedback is a critical part of gaining their buy-in for the process. As Waldron states, “We have these foreman in the room, and we need their buy-in because if we don’t have it, then they are not going to do it anyway.”

If the numbers from this initial process seemed favorable, they then conducted time studies by videotaping workers to confirm the findings of their initial interviews.

Finally, they consider the total cost of each solution, from the transportation logistics to the reduction of days onsite.

Waldron points out that you need to consider what it costs “to have a crane on site, what it costs for all the overhead to be on the job-site. If you are saving that time, you are saving money because every day you are on the job-site, you are charging money.”

Without those extensive efforts, that take into account the specific logistical challenges and opportunities associated with that site, they would be making decisions on the use of prefabrication based on other projects, and that may not truly guarantee that they can save money and eliminate waste.

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ADDITIONAL RESOURCES:

Dassault Systèms’ Lean Construction 3DEXPERIENCE® Solution
Lean Construction Institute
McGraw Hill Construction