When inspectors noticed cracks in the bottom flanges of steel plates at the Salesforce Transit Center in San Francisco, the newly opened facility was shut down. The steel spans passed all design reviews and inspections. Nevertheless, they ultimately failed from a trifecta of conditions which contractors couldn’t have foreseen, according to reporting in the Engineering News Record. Now, some are calling for changes to codes and standards for these long-span, heavy steel structures.
For contractors, examples like this suggest adopting a healthy skepticism when building structures that push the materials to their performance limits or use new and unproven methods. It also suggests builders should take into account multiple factors that might impact material integrity.
Construction projects need a lot of materials, and not all materials work out as planned. Here’s a look at other examples of troubled projects with material problems, along with some ideas for avoiding the material blues.
Administer the Contract
While the previous material gremlins came out of the blue, there are many less dramatic ones that trouble contractors every day. A portion of the Denver Airport renovation is under review because the original concrete isn’t testing strong enough to support the cranes needed for the job. And, at Oregon State University some cross-laminated timber failed, dropping two-floor panels a full story. However, upon inspection of uninstalled panels, investigators found the CLT manufacturer changed processes which compromised the bond between adhesives and material layers on between 45 and 100 panels.
Short of having someone oversee the fabricators as they build components, you’ve only got contractual and legal protections to fall back on when these material problems visit your jobsite.
Verify the specifications for shop builds. Then, get aggressive about administering the contracts to stave off material problems as well as disputes.
Your best chance to avoid these types of material problems is to start with the contract. Iron out contract errors early. Verify the specifications for shop builds. Then, get aggressive about administering the contracts to stave off material problems as well as disputes. A 2017 report on construction conflicts in North America pointed to errors in contract documents and failure to administer contracts as two of the top three reasons for disputes.
Invest in Quality Control and Use It
The primary contractors on the $2.7 billion Silver Line Metro extension in Virginia will have to protect or replace over 1,500 precast concrete panels. The defects were built into the panels at the concrete plant—the water to cement ratio was too high while rebar was cast too close to the surface. Thankfully, the contractors caught the problem through their quality control processes. While the concrete panel maker will no doubt be on the hook for the costs, the prime contractors could have faced increasing liabilities had they not discovered the problem timely.
These kinds of materials problems often go unnoticed until it’s too late as they similarly impact many off-the-shelf materials that contractors use every day. When was the last time you checked the moisture content on a shipment of lumber? If lumber you’re using has a moisture content greater than 18 percent you’re setting up the conditions for mold and mildew once you enclose the space.
When was the last time you checked the moisture content on a shipment of lumber?
Having a quality control process for materials means more than just checking sources and quality as materials arrive. It also includes maintaining optimum storage conditions.
Many materials arrive in bulk. However, they are destined for installation at a later time. Medium-density fiberboard trim, for instance, can’t take much weather. Pressure treated lumber—if not fastened down right away—often looks like roller coaster rails. Make storage an integral part of your plans and include a budget for it.
Make storage an integral part of your plans and include a budget for it.
Practice Material Due Diligence
Another important consideration is mass-produced products that don’t meet minimum required standards. Counterfeits in construction have risen sharply since 2015. In 2017, construction’s share of counterfeits was equal to all counterfeits across all industries. Sales of counterfeit materials are a $1 trillion worldwide business that threatens the finished product and safety during and after construction.
Counterfeit products often have falsified specification stamps. This leads the user to assume the product adheres to the standard expected. High-risk counterfeit products include millwork, HVAC equipment, fire control items, pipe, tubing, valves, wire, and electrical components. Counterfeits also include materials that rely on documentation that falsifies attributes. For instance, concrete is one of the top 10 construction counterfeit goods. It is often compromised by materials being substituted for Portland cement in the mix.
It might seem like a daunting task to deal with counterfeits. However, they all have one aspect in common—they seem too cheap to be true. Builders can start at the supply chain level to reduce their risks from counterfeits. Buying from suppliers that use RFID tracking is one option. It is also a good idea to train your people to be on the lookout for potential counterfeits. A little awareness can go a long way in stemming the short and long-term threats these products pose.
Use Tech To Tame Materials
Use some technology to improve your material handling and accounting. Construction material tracking software puts material knowledge in your corner by giving you total visibility into materials management. You can know the material traffic on site, fulfill material requests, and track material locations in real time.