{"id":2213,"date":"2021-05-06T10:20:13","date_gmt":"2021-05-06T02:20:13","guid":{"rendered":"http:\/\/www.bjwlx.com\/?p=2213"},"modified":"2021-10-12T17:29:22","modified_gmt":"2021-10-12T09:29:22","slug":"%e8%a3%85%e9%85%8d%e5%bc%8f%e6%a1%a5%e6%a2%81%e6%96%bd%e5%b7%a5%e4%b8%80%e7%af%87%e5%85%a8%e6%90%9e%e5%ae%9a%ef%bc%81","status":"publish","type":"post","link":"https:\/\/www.bjwlx.com\/en\/?p=2213","title":{"rendered":"Construction scheme of fabricated Bridge"},"content":{"rendered":"
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<\/p>\n <\/p>\n <\/p>\n <\/p>\n Formwork removal after concrete pouring of bearing platform and bottom section pier body<\/p>\n <\/p>\n <\/p>\n <\/p>\n<\/section>\n \u94a2\u7d22\u5854<\/p>\n<\/h3>\n
Common assembly joints are as follows:<\/h2>\n<\/section>\n
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Seismic performance of precast assembled columns<\/h3>\n
\nThe test results show that compared with the traditional cast-in-situ concrete pier, the pier with sleeve and bellows prefabricated connection structure has similar seismic performance and can meet the requirements of expected seismic performance. The precast assembled pier connected with bonded prestressed tendons has the similar deformation capacity as the cast-in-situ concrete pier, but the energy dissipation capacity is weak. In addition, through calculation and analysis, connection device test and Research on the manufacturing and transportation process of the whole batch of specimens, it is shown that the two prefabricated assembly connection modes of sleeve and bellows, the overall stress, structural connection, seismic performance and the whole construction process details of the column can meet the current design and construction requirements and can be used in engineering practice.<\/div>\n<\/div>\n
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The following points shall be paid attention to in the construction of fabricated column pier and abutment:<\/h2>\n
\nThe prestressed steel used for post tensioned prestressed reinforced concrete fabricated pier and abutment mainly includes high-strength low relaxation steel wire and cold drawn grade IV thick steel bar. The post tensioned prestressed reinforced concrete prefabricated pier and abutment can be tensioned in the following two ways: the tensioning position can be tensioned on the top of the pier cap; It can also be tensioned at the solid part of the pier and abutment bottom. Generally, the pier cap top is tensioned.<\/div>\n
\n\u2461 The anchorage end of prestressed steel tendon can be directly buried in the bearing platform without setting transition section;
\n\u2462 At the position where the stress on the section at the pier bottom is the largest, the characteristics of strong bending resistance of prestressed steel tendon can be brought into play.<\/div>\n
\n\u2461 The transition section shall be set at the pier bottom, which shall not only meet the requirements for the placement of prestressed tendon tensioning jack, but also arrange more stress-bearing reinforcement to meet the stress requirements of the section in the operation stage;
\n\u2462 The relationship between the tensioning position of prestressed tendon and vertical stressed reinforcement in transition members is complex. The tensioning requirements of prestressed tendon and grouting requirements in prestressed pipeline are consistent with the requirements of prestressed concrete beam.<\/div>\n<\/div>\n
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\nTruss system:<\/strong> bearing platform truss and pier body truss are supported on the sliding system.
\nSliding system:<\/strong> slideway and sliding device.
\nAdjustment system<\/strong>: fine adjustment measures after the formwork is in place, including horizontal adjustment of Jack and wedge.<\/div>\n<\/p>\n
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Cable tower construction<\/h2>\n<\/section>\n
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\nSteel anchor box installation control technology.<\/div>\n<\/section>\n<\/section>\n<\/section>\n<\/div>\n<\/section>\n
Steel beam cantilever construction<\/h2>\n<\/section>\n
\nAccording to different lifting methods, suspension assembly can be divided into: floating crane suspension assembly, traction pulley block suspension assembly, continuous Jack suspension assembly, cable crane (cable crane) suspension assembly and cantilever crane. The core of cantilever assembly is the transportation and assembly of beams, and the prefabrication of beam segments is the basis of cantilever assembly. The suspension assembly construction process mainly includes prefabrication, displacement, storage and transportation of beam segments; Lifting and assembly of beam section; Transformation of cantilever beam system; Construction of closure section.<\/section>\n<\/section>\nConcrete segmental beam construction<\/h2>\n<\/section>\n
\nHowever, this method also has the following shortcomings: \u2460 large floor area; \u2461 The pedestal must be built on a solid foundation. \u2462 Curved bridges also need to form the required curvature. \u2463 Pouring, curing and other equipment are mobile.<\/div>\n
\nStacking of segmental beams:<\/strong> the segments must be stacked in a way that can avoid warpage and secondary stress, and the floor can provide good support for the segments; The lower part of the web plate of the segment and the position close to the web plate shall be supported. During stacking, the weight of the upper segment shall be directly transmitted from the web plate to avoid bending and force transmission of the top and bottom plate.
\nTransportation of segmental beams:<\/strong> due to the large self weight of concrete beam segments, the precast yard of concrete beam segments is generally selected close to the bridge site and transported to the bridge site for assembly by tire transporter, beam carrier or beam rail car.<\/div>\n<\/section>\n<\/section>\n<\/section>\n<\/div>\n<\/section>\n<\/section>\n<\/div>\n<\/div>\n
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\nIt is suitable for prestressed concrete simply supported beam bridge with small and medium span, all external and internal mixing, and continuous beam bridge with simply supported and continuous span by span. The construction method is mainly composed of a steel truss guide beam with a length less than (or greater than) twice the standard span length, lifting flat car, guide beam travel and adjustment, etc.
\nIf the segments are assembled by hanging under the guide beam, the bridge erecting machine is called upper guide beam bridge erecting machine; If the segment is on the guide beam and assembled with support, the bridge erecting machine is called lower guide beam bridge erecting machine; The guide beam will bear the weight of one span precast segment.<\/div>\n<\/section>\n<\/section>\n<\/section>\n
\nSuitable for cantilever construction, medium and long-span prestressed concrete bridge with internal and external mixing.<\/div>\n<\/section>\n<\/section>\n<\/section>\n
\nMedium and long span bridges suitable for cantilever construction.<\/div>\n