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<br />seemingly illogical response. As the water increased to depths greater than <br /> <br />1 ft, the entire wall began to move backward. The gages show forward wall <br /> <br />movement during low water loads because: <br /> <br />. The wall at the locations of water pressure deflected away from the <br />loading. This caused differential lenghts in those areas to be <br />lengthened. The lengthening tended to pull the higher portions of the <br />wall, causing the wall to cup forward toward the water loading. <br /> <br />. The wall began pivoting about the lower line of horizontal wall tie <br />restraints. The lower wall ties had greater restraint than the higher <br />ties because they were closest to the base of the studs. This caused <br />the top part of the wall to pivot forward. <br /> <br />Gages below the first line of wall ties generally showed wall deflections <br /> <br />away from the water loading, while gages located higher on the wall showed <br /> <br />deflections toward the loading until the water depth was about 1 ft. After a <br /> <br />water depth of 1 ft, the higher portions of the wall began to deflect back as <br /> <br />did the entire wall. This is as one would expect because finally the water <br /> <br />loading will dominate and the wall will be pushed in the direction of the load <br /> <br />and even the oscillation in the wall will be superimposed only on the backward <br /> <br />movement of the wall. While considering the wall tie restraints, an important <br /> <br />response of the wall is illustrated; the wall oscillates between the wall <br /> <br />ties. <br /> <br />These oscillations depend upon the amount of mortar caught on the ties <br />and upon the tie locations. The deflections are similar to the deflections of <br />a continuous beam which is loaded only in certain spans. Deflection of the <br />beam shown in sketch below is loaded with a one-point load. There is a <br />tendency for the beam to deflect as shown in sketch. <br /> <br />p <br /> <br />t -- - -- <br /> <br />U-~___",,""6 li. <br /> <br />-- t.5:-----u-- <br /> <br />---u <br /> <br />- -- --- <br /> <br />The wall deflections were minimal prior to a loading of approximately <br /> <br /> <br />2 ft of water, after which relatively large deflection increases occurred for <br /> <br /> <br />very small load increases. <br /> <br /> <br />It is important to realize that the deflections of the wall, even for the <br /> <br /> <br />maximum deflection presented, are very small. The wall deflections at 4 ft of <br /> <br /> <br />water loading were in the range where careful observance was necessary to note <br /> <br />9 <br />