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 predates soil mechanics. Empirical “safe” bearing capacities were provided in many codes and reference handbooks in the late nineteenth century.

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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 in the geotechnical report.

On a lot of projects, geotechnical services are treated like a commodity. To be cost-competitive, some firms budget very little project-specific engineering and instead provide minimal interpretation of the subsurface conditions, excessively conservative design parameters and generic recommendations.

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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 a deeper bearing depth. Generally, underpinning is performed if the foundation system for an existing structure is compromised or if foundation support needs to be transferred to a deeper level to allow work that would otherwise cause foundation movement and damage to the structure. The latter scenario is common when a new building is built adjacent to an existing one.  Owners of buildings that are to be underpinned as part of adjacent construction need to know what is involved. Underpinning by a third party constructor carries with it technical and legal implications and exposes the owner to risk that may not be managed by the adjacent construction project owner and their contractors and professionals in a manner optimal to the building owner.

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What Project Owners and Developers Should Know About Temporary Structures

Construction projects often require the design, construction and use of temporary structures to provide access or protection to workers or the public, to protect adjacent structures or to support temporary loads during construction. Examples of temporary structures include excavation support systems, underpinning, scaffolds, shoring, formwork, falsework, roadway decking, roof protection and on-site contractor facilities. Ordinarily, project owners, developers and their design teams, do not need to be particularly concerned with temporary structures. They are viewed as merely the contractor’s “means and methods” and are the sole responsibility of the contractor. However, the owner and developer are stakeholders in the implementation of temporary systems on their project and should be concerned about the risks and rewards associated with temporary structures.

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Does Your Project Need a Foundation Specialist?

When I talk with people in the Architecture/Engineering/Construction industry, I often find that a lot of people working on building projects have complaints about the foundation engineering on those projects. These complaints have a few common themes:

  • Inadequate scope or data collection for subsurface explorations and geotechnical reports;
  • Excessively conservative foundation design recommendations;
  • Inappropriate, incomplete or poorly applied foundation construction recommendations;
  • Inability or unavailability of the geotechnical engineer to contribute to the design development process and refine their foundation design recommendations and parameters as the project evolves.

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