Mehdi Rastakhiz
During the design and buildability review, the plans and specifications are reviewed primarily for what is there. But during construction the impact of everything that isn’t there, or is present when it shouldn’t be, is magnified. I was trained to find what was absent and what had been incorrectly included early in my career. I remember when I started revising the plan, my mentor told me to take off my designer hat and look for things that
they are not there instead of verifying the correctness of what the plans indicate. No matter how good you are, when you finally see what’s missing, you become more humble, especially since the problems raised by what is omitted or incorrectly included can be very costly.
I once reviewed construction drawings for a 70-foot deep sewer union structure. As shown on the plans, the structure met all city standards and sewer design guidelines. What was missing was how to give access to the joining structure once an adjacent project was built.
The joint structure included steps for the operations crew to access the bottom of the pipe, an example of something that looks right but shouldn’t have been there. Deep sewers require confined space entry safety measures and personal protective equipment, and anyone entering must use a tripod and harness, not steps. Providing steps can suggest that someone should use them to gain access when they shouldn’t, and it also increases costs. Also, the steps themselves can corrode over the years due to exposure to hydrogen sulfide gas.
There is more to consider. In the design of some water and wastewater facilities, I have found that design and construction teams must consider having elbow clearance for the operating crew to work on or remove equipment. Although the crew is involved in reviewing the plans, the operators are much more hands-on, and may not be able to spot these problems by looking at the plans. Even experienced engineers and reviewers can easily miss what’s not there when looking at plans.
There are other examples of information that can disappear in action. Once our specifications provided information about the fiber optic cables we were installing around town, so our consulting engineer prepared a layout with the number of strands, color codes, type, storage and staging . It also had detailed instructions for the inspector and installer. But since what we specified could not be bought off the shelf and there was no item on offer, there was no indication as to who would supply the cable and pay for it. A change order had to be written to correct this omission.
Realistically, many agencies face scheduling and budgeting issues. Although plans and specifications go through several stages of review at most agencies, and often through an independent constructability review, there is never enough time or budget to get it right. Having perfect plans and specifications becomes almost impossible, especially in complex projects. Therefore, the last step, the constructability review, which sometimes overlaps with value engineering, is the most critical.
Once problems arise during construction or operation, many experts express their opinions about what went wrong. The best expert is the one who anticipates them before they become problems in a constructability review.
For more complex projects involving hydrogeology, structural issues, corrosion, instrumentation, or other specialties, it’s best to have an expert who knows their trade give at least a quick look to avoid fundamental mistakes. This ensures that there are no discrepancies between different disciplines and specifications and that the project can be built safely and efficiently.
The rapid pace of technological advancement also affects constructability reviews. Better products may be available for a project that was specified seven or ten years ago. There is also a generational gap between younger engineers and contractors and the more experienced and close to retirement. The older generation has an experience that the younger generation lacks.
In any project, doing vital detective work and noticing what isn’t showing and what shouldn’t be there can save you a lot of trouble and expense. This is what I have learned over many years and many projects.
