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The WPC LetterWhat's So Special About Special Inspections?
Governed by the International Code Council who in turn produces the International Building Code (IBC), special inspections are required for any project considered critical to life safety and property protection which includes most commercial and industrial projects. A qualified inspector essentially serves as the owner’s agent to verify that the structural elements of a construction project have been constructed in accordance to plans and specifications. Beyond the technical aspects of the job, special inspections can be as much about relationship building as it is engineering solutions. Design and construction projects are about people working together on a temporary basis — and a special inspector needs to recognize how important it is for these temporary teams to function as cohesive units. Therefore, when there is a discrepancy on a site, resolution often involves significantly more finesse than simply issuing a report to the structural engineer and requesting a solution. A special inspector has to have the right mix of toughness and diplomacy to keep contractors and project owners on the same page without compromising the integrity of the project. When a contractor has built something the same way for 30 years but now must strictly conform to IBC requirements and project specifications, the potential for fireworks can be high — especially when the owner is tied to a particularly tight time frame and budget. If the special inspector cannot balance a willingness to confront issues with an ability to communicate and build trust, the result will more often than not be an adversarial relationship that can put the project on the wrong track. Overall, special inspections necessitates that the owners of projects get what they are paying for whether that means the right amount of fireproofing is applied, the structural steel welding is done properly, the masonry and grouting is solid, the footings are deep enough, or the right amount of rebar has been put in place. Poorly built structures have a nasty habit of coming back to haunt their owners and those involved in their construction. When you are in the market for a special inspector, find one that can balance the technical aspects of their role, with the art of people management. Your project will be better for it. — ROBERT BELISLE, PE Rob Belisle is a licensed Professional Geotechnical Engineer with WPC. He can be reached at: rbelisle@wpceng.com or (704) 927-4000. Heavy Transportation Projects: What Lurks Beneath The Surface
When heavy transportation projects begin on shaky ground, the results can range from nuisance to catastrophe. What could go wrong at the start of a project? Not correctly predicting the settlements for an embankment. Excessive settlement in an approach embankment, for example, can mean the difference between a calm, smooth incline to the bridge and the feeling of being launched onto the bridge. Even more problematic are fundamental flaws that can occur in deep foundation design. For example, if the underlying soil conditions are not modeled correctly, the foundations may plunge or fail under seismic conditions. Understanding what the soil conditions are or what drag down forces might be affecting the foundations are critical to a safe and efficient design. Three techniques that are particularly effective in creating the right kind of foundation to support high embankments encountered in many transportation projects include mucking & replacing, surcharging, and ground improvement. Muck & Replace: One method to overcome unsuitable soils near the surface is to simply muck and replace. Bridges often cross water, and along these waterways, the soils are typically quite soft leading to excessive consolidation or difficult site conditions. Once you determine what the long-term settlement is going to be, you can muck and replace — or remove the poor soil and replace with better soil. But be cautious. Mucking and replacing is only effective if the problem is a fairly shallow one. You don’t want to replace 20 feet of muck near water — but if you are dealing with a depth of only four or five feet, mucking and replacing is a viable option. Soil Surcharge: Surcharging the soils in place is an effective method if the soft clays are significant and/or deep. Surcharging is essentially piling up fill forcing a rapid consolidation of the underlying poor soils. When the surcharge is removed, the soils should be pre-settled. The caveat is that a surcharge can take a good deal of time to work, and that extra time may not be an option depending on the project schedule. Ground Improvement: There are many different techniques that allow you to increase the strength of the soil that is already in place, such as soil mixing, stone columns, and grouting. If there is no time to do a surcharge and mucking & replacing is not an option, ground improvement may be your best bet. The quality of a heavy transportation project is directly tied to the quality of the base it is built upon — make sure you know what lurks beneath the surface early in the process to avoid trouble down the road. — TOM CASEY, PE, Jacksonville Branch Manager Tom Casey is a licensed Professional Geotechnical Engineer with WPC. He can be reached at: tcasey@wpceng.com or (904) 997-1400. |
Archived NewslettersMaterials Requiring Special Inspections
House Approves Bridge Safety Bill – Provides $1 billion for states' bridge repairs, replacements States will have additional help fixing or replacing deficient bridges under legislation overwhelmingly approved July 24, 2008 by the House of Representatives. The legislation was sponsored by Rep. James L. Oberstar (Minn.), Chairman of the House Committee on Transportation and Infrastructure. The final vote was 367-55. Source: Transportation and Infrastructure Committee For more information on the Bridge Safety bill, visit the Transportation and Infrastructure Committee website at: transportation.
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