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8.B. - Page 132 . 5-Lot Residen.tial Development December 9, 2010 <br /> � <br /> �� <br /> Tkornthwaite Moisture Indices ranging from -20 for dry condii�ons to �10 for iz�igated <br /> conditions; <br /> Edge Moisture Variation Distance(eID) <br /> Cen�er Lift Condition 5.3 feet <br /> Edge Lift Condition 4.8 feet <br /> Estimated Differential Swell(y,�) <br /> Center Lift Condition 423 inches <br /> Edge Lift Condition l.06 inches <br /> 3. The following criteria should apply to both post-tensioned slabs and stnictural mat <br /> four�datiozzs; <br /> A1.lowable Bearing Capacity(dead loads) 1,OOD psf <br /> Allowable Bearing Capacity (cEead + live lo�.ds) 1,200 psf <br /> Allowab]E Bearing Capacity(DL+LLf wind or seismic) 1,500 psf <br /> Subgrade�'rictiort Factor(slab against subgrade) 0.2 <br /> Total settlement(static) 1 inches <br /> Differential settlemen,t{s�atic) 0.5 inch <br /> 4. The building pads should be periodicaliy moisture conditioned as z�ecessary to maintain <br /> the soil moisture cantent at a minimum of 2 percent above optimum a� the tirr�e af <br /> p�acement of cancrete or vapor retarding membranes. The moisturc content of the soil <br /> shou�d be tested by a representative of this firm prior to placement of thE concrete or <br /> vapor retarding membranes. <br /> 5. Tn areas where moisture transmitted from the subgrade would be �indesirab�e, a vapar <br /> reta.rder should be uti_lized beneath the floor slab. Tl�e vapor retarder should compiy with <br /> ASTM S�dard Speci�ication E 1745-97 (Reappz-oved 200�) and the latest <br /> zecommendations of ACI Cammittee 302. The �apor re�ardez should be installed in <br /> accordance with ASTM �tandard Practice E 1643-98 (2Q05}. Care shauld be takeza ta <br /> properly lap and se�l the vapor zetazder, particularly a�round utilities, and to protect it fram <br /> damage during constructian. <br /> 6. Lf sand, gravsl or othex per�a.eable ma�erial is to be placed over the vapor retarder, the <br /> material over the vapor retazder should be oz�]y lig}atly nnoistened and not satura�ed prior <br /> to casting the slab concrete. Excess water above the vapor retarder wouid increase the <br /> potential for moisture dama.ge to floor co�erings. Recent studies, including those by ACI <br /> Commit�ee 302, have concludec� that excess water above the vapor retarder would <br /> increase the potential for rnoisture damage to floor coverings and could inerease the <br /> 12 <br />