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Purpose: To provide an alternative to piles inV Zones and A Zones in coastal areas where soil

properties and other site conditions indicate that

piers are an acceptable alternative to the usually

recommended pile foundation. Examples of ap-

propriate conditions for the use of piers are where

rock is at or near the surface or where the potential

for erosion and scour is low.

Key Issues

n The ooting must be designed or the soil condi-tions present. Pier oundations are generally notrecommended in V Zones or in A Zones in coast-al areas.

n The connection between the pier and its ootingmust be properly designed and constructed toresist separation o the pier rom the ooting andoverturning due to lateral (ood, wind, debris)orces.

n The top o the ooting must be below the antici-pated erosion and scour depth.

n The piers must be reinorced with steel and ully

grouted.

n The connection to the oor beam at the top othe pier must be through use o properly sizedand detailed metal connectors.

n Special attention must be given to the applica-tion o mortar and the tooling o all the joints inorder to help resist water intrusion into the piercore, where the steel can be corroded.

n Special attention must be given to corrosion pro-tection o joint reinorcement, accessories, an-chors, and reinorcement bars. Joint reinorce-ment that is exposed to weather or the earth

shall be stainless steel, hot dipped galvanized,or epoxy coated. Wall ties, plates, bars, anchors,and inserts exposed to earth or weather shallalso be stainless steel, hot dipped galvanized, orepoxy coated. Reinorcement bars shall be pro-tected by proper use o masonry cover.

Bedrock

Maximumdepth of erosion

and scour

Maximumdepth oferosion

and scour

Used where the potentialfor erosion and scour is high

PierPier Pile

Used only where the potentialfor erosion and scour is low orwhere the pier can beanchored to under lyingbedrock or other stratum thatterminates erosion and scour

Loss of

embedment

Overturning Uplift Erosion

Piers are subject to upward, downward, and horizontal loads.

Pier reinforcement and footing size are critical to resisting

these loads; therefore, pier and footing design must be

verified by an engineer.

HOME BUILDERS GUIDE TO COASTAL CONSTRUCTION

3.4: REINFORCED MASONRY PIER CONSTRUCTION

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HOME BUILDERS GUIDE TO COASTAL CONSTRUCTION Technical Fact Sheet No. 3.4

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Reinforced Masonry PierConstruction

Figure 1. In coastal areas, masonry pier oundationsare not recommended in V Zones with erodible soils,or in A Zones subject to waves and erosion use pileoundations in these areas.

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Piers vs. PilesPier oundations are most appropriate inareas where:

n Erosion and scour potential are low.

n Flood depths and lateral orces arelow.

n Soil can help resist overturning o

pier.The combination o high winds and moist(sometimes salt-laden) air can have adamaging eect on masonry construc-tion by orcing moisture into even thesmallest o cracks or openings in themasonry joints. The entry o moistureinto reinorced masonry construction canlead to corrosion o the steel reinorce-ment bars and subsequent cracking andspalling o the masonry. Moisture resis-tance is highly inuenced by the qualityo the materials and the quality o themasonry construction at the site.

Good Masonry PracticeI a masonry pier is determined to be an appropriateoundation or a building, there are some practicesthat should be ollowed during construction o thepiers.

n Masonry units and packaged mortar and groutmaterials should be stored o the ground andcovered.

n Masonry work in progress must be well protect-ed rom exposure to weather.

nMortar and grouts must be careully batched andmixed. The 2009 International Building Code(IBC 2009) and 2009 International ResidentialCode (IRC) speciy grout proportions by volumeor masonry construction.

n Connectors should be selected that are appro-priate or masonry to wood connection. It is im-portant to maintain a sufcient load path romthe building into the ground. The connectors andasteners should be a corrosion-resistant mate-rial or have corrosion protection at least equiva-lent to that provided by coatings in accordancewith the 2009 IRC. Connectors should be prop-erly embedded or attached to the pier. Wood incontact with masonry pier should be natural-ly durable or preservative-treated. Figure 3 il-lustrates the importance o maintaining a prop-er load path between the pier and the buildingsbeams.

n Properly sized steel reinorcing bars should beinstalled throughout the masonry piers. Piersshould be ully grouted and steel reinorcing bars

should not be let exposed to weather or exces-

sive amounts o time prior to installation. Lapsplices should be properly located and o su-fcient length to meet the standard masonry in-dustry details and requirements to sufcientlycarry the loads imposed on the structure.

n Consider incorporating grade beams into theoundation in order to achieve greater structuralstability in the pier system.

n I the design o the pier system or any details areunclear, contact a structural engineer or appro-priate design proessional to clariy the ounda-tion details.

Pros and Cons of Grade BeamsGrade beams are horizontal structural members castagainst the ground or grade. Grade beams can be auseul oundation method in areas with limited poten-tial or erosion and scour. The type o orce resistedby grade beams varies by application, but can rangerom continuous vertical and horizontal loads to axialloads. The grade beams used in this example areused primarily or axial loads generated by stabil-ity demands o the piers. The grade beams shouldbe placed below the elevation o anticipated erodedgrade so that there is no eect on scour and erosiono the supporting soils.

The pros o using grade beams with pier oundationsare that they:

n Provide vertical and lateral support.

n Are less prone to rotation and overturning.

n Transer loads imposed on the elevated homeand oundation to the ground below.

Figure 2. Pier breakage (Long Beach, Mississippi)



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FOUNDATIONS

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Some cons o using grade beams with pier ounda-tions are that they:

n Are susceptible to erosion and scour i tooshallow

n Can become obstructions during ood eventsand can increase scour

Are grade beams allowed in the V Zone?

Yes, although the NFIP states that the lowest hor-izontal structural member is to be constructedabove the BFE, it is reerring to the lowest hori-

zontal structural memberabove erodible grade.Based on this, both grade beams, cross bracingand knee bracing are allowed by the NFIP. Gradebeams can provide signifcant structural support

to an open oundation system provided they areplaced below the expected eroded surface.

Figure 3. Failure o pier-to-beam connections due towave and food orces acting on the elevated building(Long Beach, Mississippi)

Additional ResourcesAmerican Concrete Institute, 2004, SP-66(04):ACI Detailing Manual. (http://www.concrete.org)

Concrete Reinorcing Steel Institute. Placing Reinorcing Bars Recommended Practices, PRB-2-99.(http://www.crsi.org)

International Code Council. International Building Code. 2009. (http://www.iccsae.org)

International Code Council. International Residential Code. 2009. (http://www.iccsae.org)

The Masonry Society. 2008. Building Code Requirements or Masonry Structures.TMS 402-08/ACI 530-08/ASCE 5-08. (http://www.masonrysociety.org )

The Masonry Society. 2008. Specifcations or Masonry Structures.

TMS 402-08/ACI 530.1 08/ASCE 6-08. (http://www.masonrysociety.org )



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Developed in association with the National Association of Home Builders Research Center
http://www.concrete.org/http://www.crsi.org/http://www.iccsafe.org/http://www.iccsafe.org/http://www.masonrysociety.org/http://www.masonrysociety.org/http://www.masonrysociety.org/http://www.masonrysociety.org/http://www.iccsafe.org/http://www.iccsafe.org/http://www.crsi.org/http://www.concrete.org/

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