{"id":6390,"date":"2021-10-12T16:36:26","date_gmt":"2021-10-12T14:36:26","guid":{"rendered":"http:\/\/burchiello.noooserver.com\/?p=6390"},"modified":"2023-01-12T15:50:58","modified_gmt":"2023-01-12T14:50:58","slug":"mobile-bridges","status":"publish","type":"post","link":"https:\/\/www.ilburchiello.it\/en\/mobile-bridges\/","title":{"rendered":"Mobile bridges"},"content":{"rendered":"\n
\"\"<\/figure><\/div>\n\n\n\n

Nothing\nis certainly more suited to favouring social development both in terms of\nintelligence and civilization and in material economic interests, than the\nrapprochement and easy communication of the inhabitants of neighbouring\nterritories. Every impediment to this intimate relationship and every\ndifficulty opposed to social relations, produces an isolation that sadly\naffects the customs, alertness, morality and activity of a people so that in\nthe Neapolitan and Sicilian Provinces vast territories are still maintained in\na state almost wild from the lack of roads, bridges and other means\nfacilitating communications and with these the association in the idea of\nspreading the works and the prosperous merit of the trade in arts and industry.<\/em><\/p>\n\n\n\n

Part of the petition of 1867, signed by 98 inhabitants “of both banks of the Brenta”, sent to the mayor of the municipality of Oriago in order to obtain the construction of the pedestrian walkway in front of the church (ACM b.141, f. 67).<\/p>\n\n\n\n

In 2000, a study on the movable bridges\nalong the Naviglio Brenta was published by the journal “Galileo” of\nthe Order of Engineers of Padua by Michele Questioni. This study identified the\nstate in which the structures were, briefly highlighting their main\nconstruction features. It was decided to publish in this notebook the notes\npublished by “Galileo”, limited to the bridges present in the\nmunicipal territory of Mira, trying as much as possible to update them and\nenrich them in some points with the support of a documentary research in the\nhistorical archive of the Municipality of Mira; the characteristics of the\ncycle\/pedestrian walkway built in 2006 in the Valmarana area have also been\npublished.
<\/p>\n\n\n\n

<\/div>\n\n\n\n

Pedestrian\nwalkway in Mira (1863)<\/strong><\/h2>\n\n\n\n
  • \"\"<\/figure><\/li>
  • \"\"<\/figure><\/li>
  • \"\"<\/figure><\/li><\/ul>\n\n\n\n

    The work consists of a horizontal bearing\nstructure formed by two iron columns, for balancing the bridge during the\nopening phase by means of tie rods. The project is by Ing. Carlo Bragato from\nDolo, the construction of the structures by Fonderia Veneta Neville.<\/p>\n\n\n\n

    The elements of the main frame consist mainly\nof iron, steel and cast iron.<\/p>\n\n\n\n

    The bridge is 3.50 m wide, 16.76 m long,\nwith swivelling spans of 5.36+11.44 m. The structure of the deck is made up of\ntwo triangular lattice beams that act as parapets.<\/p>\n\n\n\n

    It is stiffened by 19 iron crosspieces with\na T section on which 7 secondary beams rest.<\/p>\n\n\n\n

    The 4 tie rods connecting the bridge heads\nand the pylons are integral with the rotation mechanism, to counteract the\nheeling effect when the bridge is in motion.<\/p>\n\n\n\n

    The static layout of the bridge, when\nclosed, is a continuous beam on three supports, where the external supports are\nthe shoulders; in the open position it is still a continuous beam on three\nsupports, where the external supports are the tie rods.<\/p>\n\n\n\n

    The bridge was opened on 23 August 1863;\nthis date is revealed by an exchange of letters of 21 August 1863 between\nGambarare and Dolo municipal deputations: cf. A.C.M. b. 104, f. 641 (Editor’s\nNote).
    <\/p>\n\n\n\n

    <\/div>\n\n\n\n

    Mobile\nbridge in Mira (1965)<\/strong><\/h2>\n\n\n\n
    • \"\"<\/figure><\/li>
    • \"\"<\/figure><\/li>
    • \"\"<\/figure><\/li><\/ul>\n\n\n\n

      Located in front of the Mira municipality\nbuilding, the bridge is used exclusively by vehicles, as pedestrians are\nprohibited from crossing and must use the nearby revolving pedestrian walkway.<\/p>\n\n\n\n

      In the closed position it is a structure\nwith three supports, where the central one, the pier, is fixed, while those at\nthe ends are sliding. When the bridge is open, the pivoting span behaves like a\nshelf subject to its own weight. The main supporting structure is made up of 16\nIPE 330 UNI 5398-64 beams, placed at a distance of 0.50 m, which allow to\ncontain the height of the deck. Furthermore, it can be thought that the set of\n16 longitudinal beams, the crosspieces and the upper sheet form an orthotropic\nslab. The clear navigation aperture is 7.20 m. The length of the revolving span\nis 17.85 m (5.95+11.90), 7.50 m wide; the clear height with the bridge closed\nis about 1 m, the one required by the tender specifications was less than 16\ncm.<\/p>\n\n\n\n

      To obtain the right balance of the\nstructure, due to the different dimensions between the front and the rear, a\ncounterweight was placed in the shorter part, made up of concrete blocks with\nincorporated turning shavings. The opening and closing manoeuvre is obtained in\nabout 80 seconds, by means of an electric motor or in emergency cases,\nmanually.<\/p>\n\n\n\n

      In the analysed project, the horizontal\nlock of the bridge in the closed position takes place with wedge devices\ncontrolled by a hydraulic jack. The vertical and longitudinal lock is formed by\ntwo wedge supports, at one end, controlled by hydraulic jacks; by a vertical\npin at the pier, and by three rolls at the other end.<\/p>\n\n\n\n

      The designer was Ing. Oscar Kelemina\n(Editor\u2019s Note).
      <\/p>\n\n\n\n

      <\/p>\n\n\n\n

      Mobile bridge over the Novissimo in Mira Taglio (1966)<\/strong><\/h2>\n\n\n\n
      \"\"<\/figure><\/div>\n\n\n\n

      The current bridge consists of a truss\nwhich in operation responds to the static layout of a continuous beam on four\nsupports. The two farthest supports weigh on the shoulders, the two central\nones on the pier. During opening, the weight is completely discharged on the\npier, since two strong crossbars have been placed on the bridge that distribute\nthe load on the wheel crown. Outside the pier, the two parts of the deck have\nvery different spans, so it was necessary to place a counterweight at the end\nof the shorter side. The width that can be crossed by boats is 9.54 m when the\nbridge is closed, which becomes 8.50 m when the bridge is open. The useful\nwidth of the carriageway is 6 m, in addition to two sidewalks located at the\nends, each one 1.25 m wide, raised above the road level. The revolving span is\n24 m (8.50+15.50 m). The deck consists of 13 IPE 400 longitudinal beams\nconnected by a series of crosspieces, two of which are located in\ncorrespondence with the pier and lean on the rolling rail; the space between\nthem is octagonal to allow the distribution of the load on the rail. The deck\nsheet was laid over the longitudinal beams and crosspieces, forming the\northotropic slab.<\/p>\n\n\n\n

      Rotation takes place on 16 steel idlers\nthat run on two rails, kept at the exact distance from the centre of rotation\nradially. In the longest part of the bridge, at the end, the supports are made\nwith two mobile wedges, whose height is adjustable. At the opposite end, the\nsupports consist of 3 wheels integral with the bridge. On the basis of the\ndocumentation analysed, it appears that in 1988 the bridge underwent\nextraordinary maintenance works as regards the opening system and the\nrestoration of degraded materials. It seems that there was a malfunction during\nhandling, caused by the imbalance of the permanent weights, which had the\nresulting force outside the rotation circumference.
      <\/p>\n\n\n\n

      <\/div>\n\n\n\n

      Mobile bridge in Mira Chiesa (1959)<\/strong><\/h2>\n\n\n\n

      The bridge is located in front of the Mira\nLanza factory and was the main transit route for articulated vehicles.\nOriginally the building consisted of: 2 main longitudinal beams at variable\nheights, from a minimum of 650 mm at the end, up to 1 m in correspondence of\nthe rotation axis, placed at the edge of the carriageway; 7 INP 450 crossbeams\nthat distribute the loads on the main beams; 4 INP 280 beams which unload on\nthe crossbeams; the deck is completed by a stiffened metal sheet, covered with\na bituminous wear layer.<\/p>\n\n\n\n

      In correspondence with the rotation axis,\nthe crosspieces are arranged to form an octagon which guarantees greater\nstability to the structure during the opening phase. In order to improve the\nload-bearing capacity of the structure, interventions were necessary which\nmainly concerned: the reinforcement of the INP 450 crosspieces by adding a\nlower plate; the replacement of all secondary frame elements of the deck, with\ntrapezoid-shaped box elements alongside the INP 280 beams; the replacement of\nthe old sheet with a new Fe 430 sheet, 14 mm in thickness. The static layout of\nthe bridge in the closed position is a continuous beam on three supports.<\/p>\n\n\n\n

      The bridge built in 1959 replaces the\nprevious one erected by the municipality of Gambarare in 1833 under the\npatronage of the Archduke of Austria Giuseppe Ranieri of Habsburg. “At\nMira there are two rotating iron and wooden bridges, which connect it one with\nthe Brentella, the other with Gambarare; and after crossing the second one, we\nwill enter the ancient Podest\u00e0 office of Gambarare or Fossa Gambaria.”<\/p>\n\n\n\n

      (C. Cant\u00f9, History of Venice and its\nProvince, 1859) (Editor’s Note).
      <\/p>\n\n\n\n

      Continuing along the Naviglio Brenta\ntowards Venice, near the Villa of the same name, we find the revolving bridge\nof Valmarana. This construction dates back to the late nineteenth century but\nwas dismantled only in 1966 (from Piazza Mercato, see below) and reassembled in\nits current position.<\/p>\n\n\n\n

      <\/div>\n\n\n\n

      Mobile bridge in Mira Valmarana (1880)<\/strong><\/h2>\n\n\n\n
      • \"\"<\/figure><\/li>
      • \"\"<\/figure><\/li>
      • \"\"<\/figure><\/li><\/ul>\n\n\n\n

        It is 21.97 m long, 3.60 m wide, has a\nnarrowing to limit the maximum width of vehicles in transit, which occurs in\nalternating directions. The revolving deck is made up of two longitudinal\nlattice beams on which 25 iron crossbars rest that support the wooden beams, on\nwhich the upper planking rests. The span is divided into two equal parts by the\ncentral pier; its position is such that although it is a bridge with two equal\nspans, therefore perfectly balanced, it leaves, in the open position, two\nnavigation gaps of different sizes. The central pier is circular in reinforced\nconcrete. The rotation takes place on eight wheels that run on a rail with a\ndiameter of 3.30 m, integral with the pier.<\/p>\n\n\n\n

        The bridge was designed by Dr. Pietro Gilli\nand built by the Paolo Rocchetti company from Padua.<\/p>\n\n\n\n

        Handling is manual; the operator unlocks\nthe vertical locking wedges by operating a lever on the parapet, then inserts a\ncrank in the pinion axis which is located within a small trap door in the\ncentre of the bridge and pushing it while walking round, sets in motion the\ngears that transmit the rotation to the structure until it is parallel to the\nwatercourse thus freeing the two spans for the passage of boats. (Editor\u2019s\nNote)
        <\/p>\n\n\n\n

        <\/div>\n\n\n\n

        Mobile\nbridge of Piazza Mercato in Oriago (1977)<\/strong><\/h2>\n\n\n\n
        • \"\"<\/figure><\/li>
        • \"\"<\/figure><\/li>
        • \"\"<\/figure><\/li><\/ul>\n\n\n\n

          The swing bridge, designed by Ing. Guido Ravenna,\nconsists of two steel structures, one of which is revolving, with a centre of\nrotation on a circular pier in reinforced concrete, and one is fixed.<\/p>\n\n\n\n

          These structures rest on shoulders\nsupported by poles planted in reinforced concrete. It has a total length of\n29.42 m, a width of 9.30 m, and a navigation gap of 7.50 m.<\/p>\n\n\n\n

          The framework of the bridge consists of two\nlongitudinal beams with a distance of 6 m, made of a welded structure, with a\nconstant omega section in the section near the pier that tapers towards the\nends.<\/p>\n\n\n\n

          The tapered section has been designed to\nwithstand the greatest stresses when the bridge is open, when the static layout\nis a double bracket. The beams were made with two vertical cores, an upper jack\narch and two lower plates, in order to create an easily accessible open section\nfor welding.
          <\/p>\n\n\n\n

          <\/div>\n\n\n\n

          Pedestrian\nwalkway in Oriago (1872)<\/strong><\/h2>\n\n\n\n
          \"\"<\/figure>\n\n\n\n

          Located in the town of Oriago, in front of\nthe church, it serves as a pedestrian crossing of the Naviglio Brenta.<\/p>\n\n\n\n

          In past centuries, before this work was\nbuilt, there was a “passing station” at the same point, operated with\na ferry service, to connect the opposite banks of the river. It is a sliding\nstructure on rails that partially fit into the side street.<\/p>\n\n\n\n

          It is built in iron, consisting of two\nlattice beams, on which the pedestrian level formed by wooden crossbeams, and\nthe upper planking rest. It is 17.50 m long and 1.50 m wide, is supported by a\npylon in the centre, formed by four columns with a tubular section, in cast\niron, fitted at the foot with screws for sinking. The columns are connected to\neach other with St. Andrew’s crosses that stiffen and distribute any shocks\nduring manoeuvres.<\/p>\n\n\n\n

          For sliding, four cast iron wheels are\nconnected, with cast elements, to the capitals of the columns and have a hollow\nin the extreme part that prevents any disruptions. In addition to the four\nwheels of the pier, two others, connected at the end of the deck beams, run\nalong the side street.<\/p>\n\n\n\n

          The opening takes place by activating the\nmechanism located on the right bank of the Naviglio, obtaining the sliding of\nthe structure on special rails.<\/p>\n\n\n\n

          The walkway was designed by Ing. Carlo\nBragato and built with the authorization of the Minister Secretary of State\ngranted on 13 October 1870 (A.C.M. b. 141, f. 67).<\/p>\n\n\n\n

          From a shipping note from the Neville\nfoundry, dated June 13, 1872, for the supply of \u201cNo. 2 cast iron wheels turned\nto his sample, with a turned iron pin, one of which belongs to him\n“(A.C.M. b.137, f. 43), it can be deduced that the inauguration of the\nbridge did not take place before that date. From the Bragato drawings, it can\nbe seen that the actuation for the manual opening of the bridge was not\nprovided with a wheel, but with a double crank.<\/p>\n\n\n\n

          In 2006, a modification was made to the\nopening mechanism, equipping it with electric action, the rails in the road\nwere removed and the two relative wheels were raised, a roll was inserted at\nthe end of the deck beams, in the centre of the pedestrian floor under the\nwalkway slide, obtaining the sliding of the structure directly on the road\nasphalt without however providing a special level beam designed to stiffen the\nsliding surface during the opening and closing phases (Editor\u2019s Note).
          <\/p>\n\n\n\n

          • \"\"<\/figure><\/li>
          • \"\"<\/figure><\/li>
          • \"\"<\/figure><\/li><\/ul>\n\n\n\n
            <\/div>\n\n\n\n

            Mobile\nbridge in Oriago (1990)<\/strong><\/h2>\n\n\n\n

            Built along the Naviglio Brenta, on a\nproject by Ing. Gianni Munari, it replaces a previous one (Editor’s Note: built\nbetween 1961 and 1962) no longer sufficient to meet the needs of traffic. It\nhas a length of 23.00 m and a width of 11.00 m, with two carriageways of 4.5 m\neach and two sidewalks of 1.50 m each. The pier is located on the right side of\nthe Brenta, so as to obtain a navigation passage of 7.50 m.<\/p>\n\n\n\n

            \"\"<\/figure>\n\n\n\n

            The main structure is in steel, consisting\nof: two main longitudinal beams in welded plates, which support the sidewalks;\neight crosspieces, two placed in correspondence with the rotation pier, with a\ngreater height, to make the structure more stable during the opening phase; two\nlongitudinal crosspieces. The upper sheet is stiffened by tiles. A waterproof\ncovering and the wear surface are laid over the deck sheet.<\/p>\n\n\n\n

            At the rear of the revolving deck there is\na counterweight for balance, due to the different dimensions between the cut\nand the breech.<\/p>\n\n\n\n

            Movement takes place by activating the\ncontrols placed on a special panel in the parapet, above the pier. It is\npossible to move the bridge both automatically and manually, on the basis of a\nsafety device with a programmed path that allows the execution of the next\noperation only if the previous one has been completed.<\/p>\n\n\n\n

            The bridge was inaugurated on August 18,\n1990 (Editor’s Note).
            <\/p>\n\n\n\n

            \"\"<\/figure>\n\n\n\n
            <\/div>\n\n\n\n

            Mobile\nbridge in Malcontenta (1967)<\/strong><\/h2>\n\n\n\n

            It consists of a metal structure, with a\nreinforced concrete pier positioned near the right bank of the Naviglio, and\nshoulders. The carriageway is 22.00 m long and 6.00 m wide and the sidewalks\n1.25 m.<\/p>\n\n\n\n

            It is one of the swing bridges in which the\nfree height, in the closed position, is very limited, however reflecting the\nconditions foreseen by the tender specifications that imposed, between the\nupper water level of the Naviglio and the intrados of the bridge, in\ncorrespondence of the entire navigable area, 0.90 m of space.<\/p>\n\n\n\n

            • \"\"<\/figure><\/li><\/ul>\n\n\n\n

              The main structure, according to the\noriginal project, is made up of thirteen IPE 400 beams placed at a distance of\n0.50 m, and eight crosspieces. In correspondence with the pier, where the\nrotation takes place, 5 IPE 400 beams are arranged to stiffen the structure.\nThis arrangement allows to reduce the height of the deck, forming, together\nwith the upper sheet, an orthotropic slab. In the closed position, the static\nlayout is a structure with three supports, the central one of which, the pier,\nis fixed and those at the ends are sliding. In the open position it behaves\nlike a shelf subject to its own weight. Due to the different dimensions between\nthe front and the rear, a counterweight was placed in the shorter part,\nconsisting of concrete blocks with turning chips.<\/p>\n\n\n\n

              Built to replace the one designed around\n1865 by Ing. Carlo Bragato.<\/p>\n\n\n\n

              It underwent changes around 1990. (Editor\u2019s\nNote).
              <\/p>\n\n\n\n

              <\/div>\n\n\n\n

              Cycle and\npedestrian drawbridge in Mira Valmarana (2006)<\/strong><\/h2>\n\n\n\n
              \"\"<\/figure>\n\n\n\n

              The bridge, inaugurated in December 2006,\nis the latest building in terms of time; it is 23 m long, 2.5 m wide, weighs\n180 q and the maximum lifting angle is 30 degrees.<\/p>\n\n\n\n

              Designer: Eng. Flavio Zanchettin. Builder: Costruzioni Metalmeccaniche Zara in Dolo.<\/p>\n\n\n\n

              For this work, not registered by the\nmagazine “Galileo”, we copy part of the structural report\nextrapolated from the specifications.<\/p>\n\n\n\n

              \u201cThe structure in question consists of two\ndouble-T welded beams with variable height.<\/p>\n\n\n\n

              The lower and upper flanges of each beam,\nmade up of specially calendered plates, have a thickness of 30 mm while the\ncore has a thickness of 15 mm. These beams are connected at the top to each\nother at a constant pitch of 1.5 m by 2 UNP 100 coupled profiles; at the same\ntime, the cores are stiffened both externally and internally by 10 mm thick\nplates. Every 3 m there is also a lower connection made with a double pair of\nprofiles L 80x80x8; a K-type bracing is also created, by means of 2 coupled\nprofiles 75x50x6 which converge in the middle of the lower rod.<\/p>\n\n\n\n

              Parallel to the walking surface there is a\nsystem of zig-zag bracings made with single profiles<\/p>\n\n\n\n

              L 110x110x10 that block any lateral\nsliding.<\/p>\n\n\n\n

              The deck is bound at one end by a pair of\nspindles on bushings that block the movements along each direction and only\nallow the rotation that enables the opening and closing of the bridge. This\nlatter task is carried out by a hydraulic mechanism consisting of a pair of\npistons whose liners, hinged on the right side shoulder, have an external\ndiameter of 245 mm and a bore of 200 mm; the rod has a diameter of 140 mm and a\nstroke of 1440 mm\u201d.<\/p>\n\n\n\n

              <\/div>\n\n\n\n
              \"\"<\/figure><\/div>\n","protected":false},"excerpt":{"rendered":"

              Nothing is certainly more suited to favouring social development both in terms of intelligence and civilization and in material economic…<\/p>\n","protected":false},"author":1,"featured_media":528,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"wps_subtitle":"","_links":{"self":[{"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/posts\/6390"}],"collection":[{"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/comments?post=6390"}],"version-history":[{"count":30,"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/posts\/6390\/revisions"}],"predecessor-version":[{"id":8448,"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/posts\/6390\/revisions\/8448"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/media\/528"}],"wp:attachment":[{"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/media?parent=6390"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/categories?post=6390"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ilburchiello.it\/wp-json\/wp\/v2\/tags?post=6390"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}