“Delegated Design” is the means by which the Design Professional of Record (DPOR) passes design responsibility for certain details or elements of a project to the Contractor. It provides flexibility so that proprietary materials and components can be incorporated into the project without the need to complete multiple, detailed design options in the construction contract …
Tag Archives: Risk
What Everyone Should Know About Earthquakes and Structures
Most people understand that earthquakes can produce catastrophic damage to the built environment. However, given that large earthquakes are relatively rare, and that the television news cameras typically move on a few days after any disaster, a lot of people’s understanding of the effects of earthquakes may be shaped more by bad disaster movies than …
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What’s Wrong with Your Monitoring Plan
Construction, particularly in the urban environment, often exposes nearby structures and facilities to hazards. These hazards are difficult to predict precisely and manifest as the work progresses. Impacts of this nature are associated with excavations, tunneling and foundation construction methods. Monitoring of potentially impacted structures and facilities can be necessary to control the risks associated …
Nonlinearity and the Foundation Engineer
One of the challenges of real-world engineering problems is the need to predict the behavior of a system which may be complex, dynamic, nonlinear and subject to uncertainty as to loading and response. Foundation problems are a good example of this. The behavior of a foundation is complex; it is a soil structure interaction problem …
When to Use Soil-Structure Interaction for Excavation Support Design
When structural systems are used to retain in-situ soil during excavation, the resulting soil pressures are difficult to accurately predict. In addition to the uncertainty inherent to soil materials, and the inability to fully measure those properties, the pressures on an excavation support system or permanent foundation elements that similarly retain in-situ soil and any …
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The Perils of Seal Renting and Permission Slips
I was once contacted by a marketing official of renewable energy firm looking for help with a small solar array project. His company had a solar installation designed offshore but needed an engineer licensed in the proper jurisdiction to seal the drawings…that afternoon. I balked at the request. I could not possibly perform a sufficient …
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Sometimes Lightning Strikes Twice
On 27 May 2018, a string of thunderstorms dropped several inches of rain in Howard County Maryland, causing a torrential flash flood to rise several feet above lower Main Street in Ellicott City – the second time in two years that historic central business district suffered such a severe flood. Flood waters carried away automobiles …
What’s Wrong with Commodity Geotechnical Reports
A couple of weeks ago, I was using a geotechnical report to develop a critical parameter for design of a particular foundation system. Like so many geotechnical reports I see, this report had many of the signs of being the product of commodity geotechnical services, as is often practiced when materials testing agencies offer geotechnical …
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Delaware Earthquake or Earthquakes Can Happen Anywhere
As reported by the United States Geological Survey and various news organizations, a magnitude 4.1 earthquake occurred outside Dover Delaware on November 30, subjecting much of the mid-Atlantic region to weak to light shaking. Assuming the magnitude is not revised down, it would be tied for the largest magnitude earthquake in Delaware history. No damage …
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Should Temporary Structures be Designed with Higher Allowable Stresses?
Traditionally, designers of temporary structures for use in construction had little guidance binding on their designs. Some owners, particularly infrastructure operators, provided standards and guidelines that permitted increased allowable stresses for certain temporary conditions. Sometimes the increased allowable stresses were limited to new materials or were subject to other stipulations. However, this practice came from …
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