Bélidor, Bernard Forest de, La science des ingenieurs dans la conduite des travaux de fortification et d' architecture civile

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        <div xml:id="echoid-div137" type="section" level="1" n="85">
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            <pb o="48" file="0156" n="159" rhead="LA SCIENCE DES INGENIEURS,"/>
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          <div xml:id="echoid-div222" type="section" level="2" n="50">
            <head xml:id="echoid-head170" style="it" xml:space="preserve">Remarque premiere.</head>
            <p>
              <s xml:id="echoid-s3093" xml:space="preserve">42. </s>
              <s xml:id="echoid-s3094" xml:space="preserve">On pourra ſe diſpenſer dans la pratique d’avoir égard à la
                <lb/>
              partie BQF, qui rend ce Probléme aſſés compoſé, & </s>
              <s xml:id="echoid-s3095" xml:space="preserve">n’avoir atten-
                <lb/>
              tion qu’au vouſſoir CFGD & </s>
              <s xml:id="echoid-s3096" xml:space="preserve">à la Culée MS, alors l’équation ſera
                <lb/>
              beaucoup plus ſimple, puiſque, dans l’état d’équilibre, on aura fnn
                <lb/>
              - nny = {dyy/2}, qui étant réduit donne après avoir dégagé l’inconnu
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              √{2fnn/d} + {n+/dd}\x{0020} - {nn/d} = y, dont le calcul numerique n’eſt pas long,
                <lb/>
              puiſque, pour avoir la valeur de toutes les lettres, on n’aura ſeule-
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              ment qu’à chercher celle des lignes LV, VB, & </s>
              <s xml:id="echoid-s3097" xml:space="preserve">la ſuperficie de la
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              partie CFGD; </s>
              <s xml:id="echoid-s3098" xml:space="preserve">il eſt vrai que l’épaiſſeur de la Culée ſera un peu plus
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              forte qu’elle ne devroit être pour un parfait équilibre, puiſqu’ayant
                <lb/>
              calculé cette derniere équation, j’ai trouvé qu’elle donnoit 13 pieds
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              2 pouces 8 lignes, au lieu de 11 pieds, pour la valeur de y; </s>
              <s xml:id="echoid-s3099" xml:space="preserve">mais
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              comme ce n’eſt pas l’équilibre que l’on cherche, puiſqu’il faut toû-
                <lb/>
              jours mettre la puiſſance réſiſtante au-deſſus de l’agiſſante, il vaut
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              beaucoup mieux, comme je l’ai déja dit, faire abſtraction de la
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              partie BQFC, pour trouver plus facilement l’épaiſſeur quel’on de-
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              mande & </s>
              <s xml:id="echoid-s3100" xml:space="preserve">être plus aſſuré de la ſolidité de l’ouvrage.</s>
              <s xml:id="echoid-s3101" xml:space="preserve"/>
            </p>
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          <div xml:id="echoid-div223" type="section" level="2" n="51">
            <head xml:id="echoid-head171" style="it" xml:space="preserve">Remarque ſeconde.</head>
            <p>
              <s xml:id="echoid-s3102" xml:space="preserve">43. </s>
              <s xml:id="echoid-s3103" xml:space="preserve">En cherchant l’épaiſſeur qu’il falloit donner aux Culées,
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              nous n’avons point eu égard au poids dont l’Arche pouvoit être
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              chargée au-delà du ſien propre, de la part des materiaux qui doi-
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              vent compoſer la Chauſſée & </s>
              <s xml:id="echoid-s3104" xml:space="preserve">des Voitures qui paſſeront deſſus,
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              parce que je laiſſe à la diſcretion de ceux qui ſont chargés de l’exe-
                <lb/>
              cution de ces ſortes d’ouvrages, d’en augmenter l’épaiſſeur autant
                <lb/>
              qu’ils le jugeront à propos: </s>
              <s xml:id="echoid-s3105" xml:space="preserve">je crois que ſi on l’augmentoit d’un
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              ſixiéme de ce que donne le calcul, que c’eſt la plus grande aug-
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              mentation qu’on puiſſe faire; </s>
              <s xml:id="echoid-s3106" xml:space="preserve">c’eſt-à-dire, qu’au lieu de 13 pieds 2
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              pouces 8 lignes, il faudroit lui donner environ 15 pieds & </s>
              <s xml:id="echoid-s3107" xml:space="preserve">demi.</s>
              <s xml:id="echoid-s3108" xml:space="preserve"/>
            </p>
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          <div xml:id="echoid-div224" type="section" level="2" n="52">
            <head xml:id="echoid-head172" style="it" xml:space="preserve">Remarque troiſiéme.</head>
            <p>
              <s xml:id="echoid-s3109" xml:space="preserve">44. </s>
              <s xml:id="echoid-s3110" xml:space="preserve">Nous avons ſupoſé un Pont d’une ſeule Arche, parce que
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              quand il y en auroit davantage, ce ne ſeroit jamais que la pouſſée
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              de la premiere & </s>
              <s xml:id="echoid-s3111" xml:space="preserve">de la derniere que l’on conſidéreroit pour leur </s>
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