From the Files: Lebanon City Hall Underpinning

Last week, Lebanon Opera House, the nonprofit arts and culture organization that operates the performing arts venue of the same name, kicked off its celebration of the theater’s centennial with a grand reopening following a multi-million dollar renovation project. The project featured modernized searing, an expanded lobby and improved artist-support spaces, along with an interior …

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 …

Site-Structural Engineering for the Urban Environment

Having projects in the urban environment representing a large proportion of my career experience, I am always a little surprised when I encounter design professionals and contractors who do not fully appreciate the challenges and constraints associated with building on urban sites. While a lot of design professionals, contractors and other stakeholders have urban project …

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 …

What Nate Silver Can Teach Engineers

Nate’s Silver’s book, The Signal and the Noise (The Penguin Press, New York, 2012) was released in the run-up to the 2012 election. Silver and the FiveThirtyEight.com project were well on their way to accurately predicting most of the electoral college and Senate results and there was a good deal of interest and controversy in the political media regarding …

How to Double Your Foundation’s Bearing Capacity

I saw a brief case study from a foundation contractor who had installed a proprietary pile system for a building in Northwest Washington, DC. Being somewhat familiar with the subsurface conditions and typical building heights in the area, I immediately doubted whether a deep foundation system was necessary. You will have to forgive my skepticism …

Who is Scoping Your Geotechnical Services?

Most significant new constructions projects begin with a subsurface exploration. Part of the purpose of the subsurface exploration is to provide a basis for geotechnical engineering necessary to design the foundations, earthwork, pavement and utilities for the project. In addition, the subsurface exploration and geotechnical engineer’s interpretation of the conditions observed inform the construction contractor’s pricing and …

Your Building is Probably Weightless

Well, not really…some explanation is in order. The bearing capacity is the primary design parameter for proportioning shallow foundations (i.e. footings and mats). If the average pressure applied by a footing is less than the allowable bearing capacity, then the footing area is adequate. This method has been used for over a century and actually …

Should You Have Your Geotechnical Report Peer Reviewed?

The foundation is one of the most critical components of any structure.  Poor foundation design and construction can impair the serviceability of the entire structure and put adjacent structures at risk for movement and damage. The concepts, design parameters and construction considerations for a structure’s foundation system are based on a geotechnical subsurface investigation and memorialized …

What a Building Owner Should Know About Underpinning

An environmental consultant I know once showed me a photograph of a deep excavation he had visited on a site tour. The excavation had required underpinning of a couple of brick, bearing wall buildings on the lot lines. Underpinning is the term applied to a variety of methods used to resupport a structure’s foundation, usually to …