30results about How to "Reduce mid-span deflection" patented technology

The invention discloses a totally-prefabricated assembling type reinforced concrete floor system which consists of girders, prefabricated slabs, girder-slab connecting pieces, and slab-slab connecting pieces. The invention is characterized in that: the prefabricated girders are cornice girders, and the prefabricated slabs are matchboards; the prefabricated slabs are fixedly connected by the girder-slab connecting pieces after being arranged on the prefabricated girders; and the prefabricated slabs are fixedly connected by the slab-slab connecting pieces after being lap-jointed with each other. The prefabricated slabs can be prefabricated prestressed concrete cored slabs, superimposed slabs or other flat slabs. The invention realizes the bidirectional force bearing performance of the unidirectional prefabricated slabs and the four-edge fixed-end limiting form of the floor system, and can effectively meet the requirement for large span and heavy load; moreover, belonging to a totally-assembled system, the invention has the characteristics of less field operation, high construction speed, good earthquake resisting performance, and obvious effects of energy saving and environmental protection.

The invention discloses a welding type slab crack joint for a precast concrete floor system used in a building. The welding type slab crack joint comprises an X-shaped connection piece, a cover slab type connection piece, a support plate side overhanging platform and a supported plate side overhanging platform, wherein the X-shaped connection piece consists of anchor bars, panels and panel strips; the cover slab type connection piece consists of reinforcing steels arranged at the bottom of a slab, an embedded steel plate and a cover plate; the upper ends of the support plate and supported plate sides are provided with metal embedded pieces which consist of the anchor bars and the panels; the panels of the support plate is fixedly connected with the panels of the supported plate by the panel strips to form the X-shaped connection piece; the lower ends of the support plate and the supported plate sides are embedded with metal plates which are welded with the reinforcing steels at the bottom of a precast slab; the embedded metal plates of the support plate and the supported plate are fixedly connected by a metal cover plate to form a cover plate type connection piece; and after beingoverlapped with each other, the support plate side overhanging platform and the supported plate side overhanging platform are fixedly connected by the X-shaped connection piece at the top of the slaband the cover plate type connection piece at the bottom of the slab.

The invention relates to an anti-shearing reinforcement device and method for a concrete box girder web. In order to solve the problem that in existing engineering technologies, the concrete box girder web has cracking inclined cracks and insufficient anti-shearing bearing capacity, an external vertical prestressing tendon reinforcement device and method are provided. The device comprises groove-shaped steel, L-shaped steel, vertical prestressing tendons, wedge-shaped steel cushion blocks and an anti-corrosion coating at the outer side of the web. The groove-shaped steel is horizontally fixedto the junction of the upper end of the web and a top plate in the girder length direction. The L-shaped steel (6) is horizontally fixed to the lower end of the web in the girder length direction andis parallel to the groove-shaped steel (5). The vertical prestressing tendons are vertically mounted on the groove-shaped steel and the L-shaped steel, and it is ensured that the vertical prestressingtendons are parallel to the plane of the web. According to the anti-shearing reinforcement device and method, the web is connected with the top plate and a bottom plate through finish rolling twistedsteel, the force transmission path is definite, the risk that web concrete is pulled broken is reduced, and meanwhile, midspan deformation is reduced; the problem of insufficient main tensile stressof the web concrete is effectively solved, and the situations of continuous extension of the inclined cracks of the web or new inclined cracks are prevented.

The invention provides an external prestressing overall reinforcement power station boiler large plate beam structure and a reinforcement method thereof. The large plate beam structure comprises a power station boiler large plate beam, anchor boxes, supporting beams, prestressed pull cables, hanging rods, connecting beams and the like. The supporting beams comprise vertical supporting beam bodies and horizontal supporting beam bodies, and the vertical supporting beam bodies and horizontal supporting beam bodies are connected through cover plates by adopting high-strength bolts; the horizontal supporting beam bodies make contact with the lower edges of lower flanges through cushion plates; the supporting beams are connected through the connecting beams to form a combined member; and the pull cables are symmetrically arranged on the two sides of a web of the large plate beam and directly or indirectly connected with the supporting beams through the hanging rods by adopting cable clamps. In order to reduce the prestress loss in the pull cables, arc-shaped rotation devices can be arranged between the hanging rods and vertical supporting beam top plates to enable the hanging rods to rotate by small angles; and through external prestressing overall reinforcement of the boiler large plate beam, the large plate beam lower flange tensile stress is reduced, the internal force state of the large plate beam structure is optimized, and surface crack propagation at a lower flange splicing weld seam is effectively inhibited.

The invention discloses a method for longitudinal arrangement of temporary bracings in transverse-partitioning construction of a steel box girder. The method particularly comprises the following steps: as a top plate and a bottom plate at an end part have the maximum slippage after the steel box girder is partitioned transversely, arranging two temporary cross bracings at two end parts on an opening side respectively, and then making a modeling analysis to compare the slippage of the top plate and the bottom plate; arranging another two cross bracings at parts with the maximum slippage, and making a modeling analysis to compare the slippage of the top plate and the bottom plate; and repeating the process until deformation meets engineering requirements. The temporary bracings are arranged on the web-absent opening side of a bridge block in the transverse direction of a bridge, with one longitudinal stiffening rib behind, and the supporting points of the temporary bracings are set at the junctions of diaphragm plates and the top and bottom plates. Through the method, the mid-span deflection can be reduced to the greatest extent with fewest temporary bracings. The method is simple and easy and maximizes the supporting efficiency.

The invention discloses a stagger anchoring arrangement mode for overlong prestress steel cables and a construction method. A plurality of prestress short cables are included, the multiple prestress short cables are alternately distributed at the two sides of the position of the center cross section of a pier top, and one end of each cable is fixedly anchored on the cross section of an original cantilever end, and the other end of each cable is fixedly anchored on the cross section of the pier top at the opposite side of the cantilever end; and the ends, on the center cross section of the pier top, of the multiple prestress short cables are partially overlapped to form a stagger anchoring area of overlapped anchoring on the pier top. According to the stagger anchoring arrangement mode for the overlong prestress steel cables, the prestress steel cables are reasonably arranged and anchored, the long cables are properly changed to the short cables, and since prestress loss is closely linked to the length of the prestress steel cables, the prestress loss, caused by friction between steel strands and pipeline walls, looseness of steel bars and the like, of overlong prestress steel cables is decreased greatly, and therefore the mid-span deflection caused by the excessively large prestress loss is decreased.

The invention relates to a heavy-duty large-span composite beam-column structure and a construction method. The structure includes: a column, which is a steel column or a steel-reinforced concrete column; Incision; end plate, vertically arranged in the incision, and welded with the web and upper flange of H-shaped steel; long-span composite beam, connected with cantilever beam by bolt welding, composed of round steel pipe and T-shaped steel, round steel pipe Arranged above the web of the T-shaped steel and welded with the web, the end face of the round steel pipe is welded to the outer surface of the end plate, the web and lower flange of the T-shaped steel are connected with the web and lower flange of the H-shaped steel by connecting plates and high-strength bolts connect. The long-span composite beam-column structure provided by the present invention is especially suitable for bearing heavy loads on the roof, and has high rigidity, clear load transmission, low mid-span deflection, high bearing capacity and good integrity. The structure is simple, the height and width of the section are small, and the material is saved.

Disclosed is a pretensioning method for converting an old simply supported girder bridge into a continuous girder bridge, including the following steps: pre-burying a first steel plate and a second steel plate respectively on both to-be-connected sides of the old simply supported T girder, and drilling holes on the steel plates in advance corresponding to the position paved with connecting prestressing tendons; wherein, the size of holes is big enough for the prestressing tendons to run through; threading the prestressing tendons in the holes of the steel plates, anchoring one end of each prestressing tendon, and connecting the other ends of the prestressing tendons which thread through the first steel plate and the second steel plate through a connector; wherein, the holes of the two prestressing tendons on the first steel plate and the second steel plate are opposite and the prestressing tendons are placed inside the holes; screwing down the connector and tensioning the prestressingtendons; propping and pushing the girder outwards through a jack; widening the to-be-connected ends of the T girders, arranging a lateral clapboard between the connected ends of the to-be-connected Tgirders, and casting concrete on the connected ends and the bridge deck; and removing the jack after the newly cast concrete reaches the designed tension. In this way, prestress can be transferred tothe negative moment area of the reinforced concrete T girder through the old and the new concrete interfaces.

The invention relates to a three-span antinode I-shaped beam-transverse wave-three-steel and concrete combined T-shaped continuous beam which comprises an antinode I-shaped beam (1) and a steel concrete combined top plate (2). A bridge span has a three-span continuous beam structure, and the setting of camber is not required. The invention firstly discloses an upper flange plate and a lower flange plate of the antinode I-shaped beam and are respectively parallel and level to a top plate and a bottom plate of the beam; the function of an antinode I-shaped beam reinforcing framework is fully utilized; temporary facilities used for pouring concrete on the top plate and the bottom plate are simplified; and concrete reinforcing bars are wrapped on the corrugated steel webs on the position of a supporting base along the length direction of a bridge and the thickness directions on the two sides, so that the maximum crushing stress of the lower edge of the section of the continuous beam supporting base is reduced, the buckling of the corrugated steel lower flange plate under the crushing stress is improved, and the diffusion of the concentrated force on the supporting base is benefited. The T-shaped continuous beam provided by the invention is high in construction speed and high in bearing capacity, requires no tensioning pre-stress, and is especially suitable for urban flyovers and engineering under strictly controlled under-bridge interference and tense working periods.