Summary of the invention
The technical problem to be solved in the present invention is the prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam and construction method thereof that a kind of structure of proposition is simple, prefabrication and lifting operation is easy, economic performance is good.
For solving the problems of the technologies described above, the present invention is by the following technical solutions: prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam, the span centre position of case beam adopts fish belly ellbeam section, fish belly sill section bottom flange is the concrete edge of a wing, the web of span centre fish belly sill section adopts Wavelike steel webplate, pedestal beam section adopts contour concrete box girder, the prestressing with bond bundle that stretch-draw is elongated in span centre fish belly sill section concrete bottom flange-pedestal beam section concrete box girder web.
The bottom flange curve of span centre fish belly sill section adopts circular curve, parabola or catenary.
The ratio of span centre deck-molding and girder span footpath L controls between 1/13-1/25.
Combined box beam pedestal beam section cross section adopts contour box section, and the intersection cross section that contour box section and fish belly sill section uprise cross section is greater than 1/20 of girder span footpath with the cross-sectional distance starting to arrange Wavelike steel webplate.
Span centre Wavelike steel webplate controls between the 1/2-3/4 in girder span footpath along the arrangement length of beam longitudinal direction.
The contour case depth of beam of pedestal beam section and the ratio of span centre fish belly sill maximum height control between 1/2-2/3.
The construction method of above-mentioned prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam, comprises the following steps:
The prefabricated Wavelike steel webplate of <1>, by fish belly web required form prefabricated processing Wavelike steel webplate and the upper and lower steel edge of a wing thereof and shear connector;
<2> sets up box beam concrete template, assembling reinforcement, and by prefabricated Wavelike steel webplate location and installation on concrete blinding, in span centre fish belly sill section concrete bottom flange-pedestal beam section concrete web, arrange bellows, corrugated tube end is arranged on web plate and top board juncture area;
<3> concreting, the elongated presstressed reinforcing steel in curing concrete post tensioning span centre fish belly sill section concrete bottom flange-pedestal beam section concrete web, forms fish belly Wavelike steel webplate prestressing with bond combined box beam.
Have smooth-going changeover portion starting the web arranged near Wavelike steel webplate cross section, transition section length is between L/20-L/30.
The intersection cross section uprising cross section in the contour cross section of standoff region and fish belly sill arranges concrete diaphragm.
Concrete diaphragm is set in span centre fish belly sill section, Wavelike steel webplate welds WELDING STUDS in order to connect; Diaphragm adopts concrete porosity diaphragm, and WELDING STUDS arranges in row vertical distribution 2-3 on Wavelike steel webplate.
For the technical barrier that Wavelike steel webplate beam external pre-stress bundle durability is low, inventor designs a kind of prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam, the span centre position of case beam adopts fish belly ellbeam section, fish belly sill section bottom flange is the concrete edge of a wing, the web of span centre fish belly sill section adopts Wavelike steel webplate, pedestal beam section adopts contour concrete box girder, the prestressing with bond bundle that stretch-draw is elongated in span centre fish belly sill section concrete bottom flange-pedestal beam section concrete box girder web.Presstressed reinforcing steel is in the web of beam end and the position anchoring of top board boundary, and Wavelike steel webplate adopted by span centre fish belly sill section web significantly can reduce bridge deadweight, is beneficial to prefabricated, lifting, reduces the cost of beam body; Meanwhile, the prestressing with bond bundle that in span centre fish belly sill section concrete bottom flange-pedestal beam section concrete box girder web, stretch-draw is elongated, solves the problem that Wavelike steel webplate composite beam bridge external prestressing durability is low.Accordingly, inventor also establishes corresponding construction method, adopts this method construction safety, convenient, fast.In a word, the present invention significantly improves the rigidity of beam body, avoids the air exposure of the prestressed cable of Wavelike steel webplate compound beam, significantly improves durability and the reliability of combined beam structure, removes the large obstacle that Wavelike steel webplate compound beam is promoted on a large scale.
Accompanying drawing explanation
Fig. 1 is that the facade of prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam of the present invention arranges schematic diagram.
Fig. 2 is the schematic perspective view of prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam of the present invention.
Fig. 3 is the highway engineering compound beam facade arrangement diagram in application 1.
Fig. 4 is the span centre cross sectional arrangement figure in Fig. 3.
Fig. 5 is the bearing uniform section cross sectional arrangement figure in Fig. 3.
Fig. 6 is the railway engineering compound beam facade arrangement diagram in application 2.
Fig. 7 is the span centre cross sectional arrangement figure in Fig. 6.
Fig. 8 is the bearing uniform section cross sectional arrangement figure in Fig. 6.
In figure: 1 case beam top flange plate, 2 bearing uniform beam section webs, the bottom wing listrium of 3 Wavelike steel webplate compound beam sections, the changeover portion of 4 bearing uniform beam sections and compound beam section is near top flange concrete web, the changeover portion of 5 bearing uniform beam sections and compound beam section is near bottom flange concrete web, 6 bottom wing listriums near the contour cross section of bearing, elongated prestressing tendon in 7 span centre fish belly sill section bottom flange-pedestal beam section webs, 8 span centre Wavelike steel webplates, 9 Wavelike steel webplate top flange steel plates, 10 Wavelike steel webplate bottom wing listriums, 11 diaphragms, 12 top flange plates wet seam, 13 diaphragms wet seam, 14 without tiny fragments of stone, coal, etc. guidance tape, 15 high ferro rails, 16 pedestal beam sections, 17 span centre fish belly sill sections, 18 WELDING STUDS.
Detailed description of the invention
One, the basic structure (Fig. 1 to 2) of prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam
The span centre position of case beam adopts fish belly ellbeam section, fish belly sill section bottom flange is the concrete edge of a wing, the web of span centre fish belly sill section adopts Wavelike steel webplate, pedestal beam section adopts contour concrete box girder, the prestressing with bond bundle that stretch-draw is elongated in span centre fish belly sill section concrete bottom flange-pedestal beam section concrete box girder web.
By the mechanical calculation to multiple curve, the bottom flange curve of span centre fish belly sill section adopts these 3 kinds of linear forces of circular curve, parabola or catenary the most rationally and configuration is graceful.
Based on mechanical calculation and statistical analysis, this span centre deck-molding can select higher value with the ratio in girder span footpath when larger across footpath, because span centre fish belly section adopts steel web, adopt larger span centre deck-molding significantly can't increase the deadweight of girder with the ratio in girder span footpath, and the increase of span centre position deck-molding significantly can promote the rigidity of girder, load promotes Be very effective; In addition, railway bridge should adopt larger span centre deck-molding and the ratio in girder span footpath, and to bear larger train load, the span centre deck-molding of 1/13 can meet the use of 10,000 tons of heavy trains with the ratio in girder span footpath.Another according to mechanical calculation, if span-depth radio is less than 1/25, then the height needed for pedestal beam section cross section can be greater than spaning middle section height, the non-fish belly sill form of beam body.Therefore the ratio of span centre deck-molding and girder span footpath L controls between 1/13-1/25.
Combined box beam pedestal beam section cross section adopts contour box section, and the intersection cross section that contour box section and fish belly sill section uprise cross section should be greater than 1/20 of girder span footpath with the cross-sectional distance starting to arrange Wavelike steel webplate.Because there is larger rigidity when suddenling change in the intersection cross section uprising beam section in the contour cross section of pedestal beam section and span centre fish belly sill, also larger rigidity sudden change can be there is in the cross section starting to arrange Wavelike steel webplate, so the distance between these two abrupt-change cross sections should be controlled, suddenly change to prevent the rigidity in two cross sections and occur superposition and cause structural mutation place tensile stress excessive.By FEM (finite element) calculation, these two rigidity abrupt-change cross section spacing are greater than 1/20 of girder span footpath, and the concrete pulling stress of Wavelike steel webplate and concrete web connecting portion can be made to meet the requirement of concrete tension design load.
Known according to quantities calculation statistics, span centre Wavelike steel webplate controls between the 1/2-3/4 in girder span footpath along the arrangement length of beam longitudinal direction, about can alleviate the deadweight of girder 20%-30%, the uniform beam segment length (L/8-L/4) of the close bearing stayed just can meet the demand of the arrangement space of prestressing with bond in pedestal beam section web.
The contour case depth of beam of pedestal beam section and the ratio of span centre fish belly sill maximum height control between 1/2-2/3.Determine according to the design shear of girder along the cut to lengthen of girder near standoff region web, the design shear near bearing should meet:
V≤t
fh
ff
v+0.75A
gf
gtanθ+A
sf
stanθ
In formula, V is design shear, tf is web thickness, hf_ is web height, and fv is web shear strength design load, and Ag is the steel strand gross area, fg is steel strand tensile strength design load, θ is steel strand or the ladle concrete edge of a wing and horizontal direction angle, and As is ladle edge of a wing steel area, and fs is ladle edge of a wing steel tensile strength design load.
Two, the construction method of prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam
The prefabricated Wavelike steel webplate of <1>, by fish belly web required form prefabricated processing Wavelike steel webplate and the upper and lower steel edge of a wing thereof and shear connector;
<2> sets up box beam concrete template, assembling reinforcement, and by prefabricated Wavelike steel webplate location and installation on concrete blinding, in span centre fish belly sill section concrete bottom flange-pedestal beam section concrete web, arrange bellows, corrugated tube end is arranged on web plate and top board juncture area;
<3> concreting, the elongated presstressed reinforcing steel in curing concrete post tensioning span centre fish belly sill section concrete bottom flange-pedestal beam section concrete web, forms fish belly Wavelike steel webplate prestressing with bond combined box beam.
Wherein, should have smooth-going changeover portion starting the web arranged near Wavelike steel webplate cross section, transition section length is between L/20-L/30.By FEM (finite element) calculation, arrangement length is that concentrated tensile stress can be reduced to and do not establish less than 1/3 of changeover portion by the web changeover portion of L/30-L/20, can meet concrete tensile strength designing requirement.
The intersection cross section uprising cross section in the contour cross section of standoff region and fish belly sill should arrange concrete diaphragm, to increase the torsional rigidity of this section, reduces the impact of torsional rigidity sudden change.
Concrete diaphragm is set at span centre fish belly sill Duan Ruoxu, WELDING STUDS can be welded in order to connect on Wavelike steel webplate.Diaphragm generally adopts concrete porosity diaphragm to alleviate deadweight, and WELDING STUDS arranges in row vertical distribution 2-3 on Wavelike steel webplate.
Three, the application of prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam
Application examples 1 (Fig. 3 to 5)
Certain speedway Viaduct Design is 40m across footpath, the ooze section low bearing capacity of project site, therefore require that the weight of superstructure girder reduces 20%-30%, require to reduce cost and girder can prefabrication and lifting simultaneously, therefore the prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam adopting the present invention to propose is as the scheme of superstructure.
Main span is 40m, and span centre deck-molding elects 1/14 as with the ratio across footpath, and span centre deck-molding is 2.8m, and bearing deck-molding is 1.8m, two-way 6 tracks, and bridge design width is 21.5m.Adopt 4 case beams.The wide 5m of end face of every sheet case beam, top plate thickness is 20cm, and web thickness is 18cm, and base plate thickness is 25cm.In concrete web, elongated prestressing with bond steel strand are set along beam near the concrete slab-bearing of span centre fish belly type bottom flange.The facade arrangement diagram of beam is shown in Fig. 3, and span centre cross sectional arrangement figure is shown in Fig. 4, and bearing uniform section section cross sectional arrangement figure is shown in Fig. 5.Fish belly Wavelike steel webplate prestressing with bond combined box beam is prefabricated complete after, adopt loop wheel machine by beam body lift, and build bridge floor, diaphragm wets seam, formed bridge superstructure.
Application examples 2 (Fig. 6 to 8)
The design of certain high speed railway box girder is 30m across footpath, owner unit requires to adopt case beam (without tiny fragments of stone, coal, etc. guidance tape), the weight of case beam needs to alleviate 30%, prohibit the use external pre-stress bundle, girder need adopt prefabrication and lifting mode to construct, therefore the prefabrication and lifting fish belly Wavelike steel webplate prestressing with bond combined box beam adopting the present invention to propose is as the scheme of superstructure.
Main span is 30m, and span centre deck-molding elects 1/13.5 as with the ratio across footpath, and span centre deck-molding is 2.2m, and bearing deck-molding is 1.5m, and arrange two rail, bridge floor is wide is 9m.Adopt 2 case beams, every sheet back face width 4.35m, top plate thickness is 20cm, and web thickness is 20cm, and base plate thickness is 25cm.The facade arrangement diagram of beam is shown in Fig. 6, and span centre cross sectional arrangement figure is shown in Fig. 7, and bearing uniform section section cross sectional arrangement figure is shown in Fig. 8.Fish belly Wavelike steel webplate prestressing with bond combined box beam is prefabricated complete after, adopt loop wheel machine by beam body lift, and build bridge floor, diaphragm wets seam, formed bridge superstructure.
Practice shows, the present invention and conventional concrete case beam contrast, and deadweight reduces 20%-30%, comprehensive cost reduces about 10%, Wavelike steel webplate compound beam uses elongated prestressing with bond bundle, avoids the atmospheric exposure of Wavelike steel webplate externally cable, improve the durability of bridge, and can easily prefabricated with lifting girder, situ wet workload is little, and lifting is quick, safety, without airborne dust operation, economic and social profit is good, has very strong competitive advantage.Table 1 list Wavelike steel webplate pre-stressed box of the present invention and ordinary concrete case beam, common Wavelike steel webplate beam, steel box-girder important technological parameters contrast.
The important technological parameters of table 1 Wavelike steel webplate of the present invention pre-stressed box and ordinary concrete case beam, common Wavelike steel webplate beam, steel box-girder