FEMA P55 Coastal Construction Manual, Fourth Edition - Mad Cad

1 CHAPTER TITLE
COASTAL CONSTRUCTION MANUAL
10 Designing the Foundation
This chapter provides guidance on designing foundations,
including selecting appropriate materials, in coastal areas. It
CROSS REFERENCE
provides general guidance on designing foundations in a coastal
environment and is not intended to provide complete guidance For resources that augment the
guidance and other information in
on designing foundations in every coastal area. Design
this Manual, see the Residential
professionals should consult other guidance documents, codes, Coastal Construction Web site
and standards as needed.
(http://www.fema.gov/rebuild/
mat/fema55.shtm).
Design considerations for foundations in coastal environments
are in many ways similar to those in inland areas. Like all
foundations, coastal foundations must support gravity loads, resist uplift and lateral loads, and maintain
lateral and vertical load path continuity from the elevated building to the soils below. Foundations in coastal
areas are different in that they must generally resist higher winds, function in a corrosive environment,
and withstand the environmental aspects that are unique to coastal areas: storm surges, rapidly moving
floodwaters, wave action, and scour and erosion. These aspects can make coastal flooding more damaging
than inland flooding.
Like many design processes, foundation design is an iterative process. First, the loads on the elevated structure
are determined (see Chapter 9). Then a preliminary foundation design is considered, flood loads on the
preliminary design are determined, and foundation style is chosen and the respective elements are sized to
resist those loads. With information on foundation size, the design professional can accurately determine
flood loads on the foundation and can, through iteration, develop an efficient final design.
Because flood loads depend greatly on the foundation design criteria, the discussion of foundation design
begins there. The appropriate styles of foundation are then discussed and how the styles can be selected to
reduce vulnerability to natural hazards.
COASTAL CONSTRUCTION MANUAL
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