Alberti, Leone Battista, Architecture, 1755

List of thumbnails

< >
311
311 		312
312
313
313 		314
314
315
315 		316
316
317
317 		318
318
319
319 		320
320
< >
page |< < of 320 > >|
    <archimedes>
      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb xlink:href="003/01/319.jpg" pagenum="239"/>
              diſcover whether they are from thence, or from
                <lb/>
              ſome other Cauſe by certain Symptoms. </s>
              <s>Thus
                <lb/>
              to begin with Cracks in the Wall; to which ſo­
                <lb/>
              ever Side the Crack runs in its Aſcent, on that
                <lb/>
              Side you may be ſure the Cauſe of the Defect
                <lb/>
              lies ſomewhere in the Foundation. </s>
              <s>If it does
                <lb/>
              not verge to either Side, but runs up in a direct
                <lb/>
              Line, and grows wider at the Top, then let us
                <lb/>
              take a careful View of the Courſes of Stone­
                <lb/>
              work on each Side; for on which ever Side
                <lb/>
              they ſink from their Level, on that Side we
                <lb/>
              may be ſure the Foundation has failed. </s>
              <s>But
                <lb/>
              if the upper Part of the Wall is entire, and
                <lb/>
              there are Cracks in ſeveral Places towards the
                <lb/>
              Bottom, which in their Aſcent run together
                <lb/>
              cloſe at Top; then we may be ſatisfied that
                <lb/>
              the Corners of the Building ſtand firm, and
                <lb/>
              that the Defect is ſomewhere about the Mid­
                <lb/>
              dle in the Foundation. </s>
              <s>If there is but one
                <lb/>
              Crack of this Sort, the higher up it goes, the
                <lb/>
              the more it ſhews the Corners to have given
                <lb/>
              Way. </s>
              <s>In order to ſtrengthen the Foundations
                <lb/>
              in any of theſe Caſes, according to the Magni­
                <lb/>
              tude of the Structure and the Solidity of the
                <lb/>
              Ground, dig a narrow Pit near the Wall, but
                <lb/>
              ſo deep as to come to a firm Soil, and there
                <lb/>
              breaking through the Bottom of the Wall,
                <lb/>
              immediately work up to it with ſquare Stone,
                <lb/>
              and then leave it to ſettle. </s>
              <s>When that is ſet­
                <lb/>
              tled, dig another Pit in another Part, and un­
                <lb/>
              derprop it in the ſame Manner, and in the ſame
                <lb/>
              Manner give it Time to ſettle. </s>
              <s>By this Means
                <lb/>
              you will make a Kind of new Foundation to
                <lb/>
              the whole Wall. </s>
              <s>But if even by digging you
                <lb/>
              cannot come at any firm Ground, then make
                <lb/>
              Holes in certain Places not too near the Cor­
                <lb/>
              ners, but pretty cloſe to the Foundation of the
                <lb/>
              Wall, on both Sides, that is to ſay, as well un­
                <lb/>
              der the Roof as under the open Air, and into
                <lb/>
              thoſe Holes drive Piles as cloſe as they will ſtick,
                <lb/>
              and over them lay the ſtouteſt Summers you
                <lb/>
              can get lengthways, with the Sides of the Wall.
                <lb/>
              </s>
              <s>Then acroſs theſe Summers lay the ſtrongeſt
                <lb/>
              Girders running under the Bottom of the
                <lb/>
              Foundation, which muſt reſt with their whole
                <lb/>
              Weight upon theſe Girders, as it were upon a
                <lb/>
              Bridge. </s>
              <s>In all theſe Reparations great Care
                <lb/>
              muſt be taken that no Part of the new Work
                <lb/>
              be too weak to ſupport the Weight which is to
                <lb/>
              bear upon it, and that for ever ſo long
                <lb/>
              Time: becauſe the whole Pile bearing towards
                <lb/>
              that weaker Part, would immediately fall to
                <lb/>
              Ruins. </s>
              <s>But where the Foundation has given
                <lb/>
              Way ſomewhere about the Middle of the Wall,
                <lb/>
              and the upper Part does not appear to be af­
                <lb/>
              fected by the Crack, then upon the Face of
                <lb/>
              the Wall mark out with your Oker an Arch
                <lb/>
              as large as the Caſe requires, or, in other Words,
                <lb/>
              ſo big as to take in all that Part of the Wall
                <lb/>
              which is ſunk. </s>
              <s>Then beginning at one End
                <lb/>
              of this Arch, break into the Wall with an
                <lb/>
              Opening not bigger than one Stone of your in­
                <lb/>
              tended Arch will fill up; which Stones in an
                <lb/>
              Arch we formerly called Wedges, and im­
                <lb/>
              mediately inſert one of theſe Wedges in ſuch a
                <lb/>
              Manner that its Lines may exactly anſwer to
                <lb/>
              the Center to which you have deſcribed your
                <lb/>
              Arch. </s>
              <s>Then make another Break cloſe above
                <lb/>
              it, and fill it up with another ſuch Wedge;
                <lb/>
              and ſo continuing the Work ſucceſſively,
                <lb/>
              compleat your whole Arch: and thus you
                <lb/>
              may fortify you Wall without Danger. </s>
              <s>If a
                <lb/>
              Column or any other of the Ribs of the Building
                <lb/>
              is weakened, you may reſtore it in the following
                <lb/>
              Manner. </s>
              <s>Underprop the Architrave with a
                <lb/>
              ſtrong Arch of Tile and Plaiſter beat together,
                <lb/>
              as alſo with Piers of Plaiſter rais'd for this
                <lb/>
              Purpoſe, in ſuch a Manner that this new Arch
                <lb/>
              may quite fill up the old Intercolumnation, or
                <lb/>
              Aperture between the Ribs: and let this un­
                <lb/>
              derproping be run up as faſt as poſſible, and
                <lb/>
              without the leaſt Intermiſſion. </s>
              <s>It is the Nature
                <lb/>
              of Plaiſter to ſwell as it dries: ſo that this new
                <lb/>
              Work, though quite freſh, will be able to take
                <lb/>
              upon itſelf and ſuſtain the Weight of the old
                <lb/>
              Wall Vault. </s>
              <s>Then, having before got ready
                <lb/>
              all your Materials, take out the defective
                <lb/>
              Column, and ſupply its Place with a ſound
                <lb/>
              one. </s>
              <s>If you chuſe rather to reſt the old Wall
                <lb/>
              upon Timbers, then underſhore it with Levers
                <lb/>
              made of ſtrong Beams, and load the longer
                <lb/>
              Ends of thoſe Levers with Baskets filled with
                <lb/>
              Sand, which will raiſe up the Weight by de­
                <lb/>
              grees equally and without any Shocks. </s>
              <s>If the
                <lb/>
              Wall is ſwerved from its Perpendicular, fix
                <lb/>
              Planks or Timbers upright againſt it, and
                <lb/>
              againſt each of theſe ſet a ſtrong Timber by
                <lb/>
              Way of Shore, with its Foot ſtretching at ſome
                <lb/>
              Diſtance from the Wall. </s>
              <s>Then either with
                <lb/>
              Levers or with Wedges, drive forwards the Feet
                <lb/>
              of the Shores by degrees, ſo as they may preſs
                <lb/>
              againſt the Wall, and ſo by diſtributing this
                <lb/>
              Force equally in all Parts, you will raiſe the
                <lb/>
              Wall again to its perpendicular. </s>
              <s>If this
                <lb/>
              cannot be done, prop it up with Shores of
                <lb/>
              Timber fixed well in the Ground, with their
                <lb/>
              Ends well daubed over with Pitch and Oil to
                <lb/>
              prevent their being corroded by the Touch of
                <lb/>
              Mortar; then erect Buttreſſes of ſquare Stone,
                <lb/>
              built ſo as to encloſe thoſe Shores of Timber. </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
Impressum