Prestressed bailey beam for reinforcement and construction method therefor

Abstract

A Bailey beam for reinforcement is composed of Bailey panels, stiffening rods, bolts, anchor bolts, a prestressing tendon and anchorages. The components of the Bailey beam are all prefabricated in a factory, and are assembled and hoisted on site. The prestressing tendon is arranged in a lower chord of the Bailey beam, and is anchored to the stiffening rods at both ends. The Bailey beam slides towards both ends during prestress tensioning. In this case, the Bailey beam is lifted as a whole, and the prestressing force is applied to a lower edge of the Bailey beam, resulting in an inverted arch of structure, closing up of cracks and a decrease in downward deflection. After the completion of the prestress tensioning, sealing is performed by fixing fillers, a sealing steel plate and injecting solidifiable materials.

Claims

1. A prestressed Bailey beam for reinforcement, comprising Bailey panels, anchor bolts, two stiffening rods, bolts, nuts and a prestressing tendon, wherein the Bailey panels comprise a front Bailey panel, an end Bailey panel, and a middle Bailey panel set, all Bailey panels are linked end-to-end in sequence, the front Bailey panel and the end Bailey panel are installed on both ends of the prestressed Bailey beam respectively, the middle Bailey panel set is installed between the front Bailey panel and the end Bailey panel and a number of the middle Bailey panel is n pairs, wherein n is a natural number, a plurality of elongated sliding grooves are formed at both an upper chord and a lower chord of each of the Bailey panels, the anchor bolts pass through the elongated sliding grooves and are fixed on a structure to be strengthened, the two stiffening rods are disposed on the front Bailey panel and the end Bailey panel respectively, one end of each of the stiffening rods is connected to the upper chord of the front Bailey panel and end Bailey panel respectively through a corresponding one of the bolts, each of the anchor bolts passes through a central position of a respective stiffening rod and is fixed on the structure to be strengthened so as to function as a fulcrum for each respective stiffening rod to rotate, an anchorage is disposed at the other end of each of the stiffening rods, the prestressing tendon passes through the two anchorages on the two stiffening rods, and the nuts are screwed into the anchor bolts and are tightened to fix positions of the Bailey panels after completion of tensioning of the prestressing tendon.

2. The prestressed Bailey beam for reinforcement according to claim 1, wherein a cylinder is disposed on each of the stiffening rods at the other end where each anchorage is disposed, an elongated prestressing tendon groove passing entirely through each cylinder is formed in a diameter direction of a cross section of each cylinder, each anchorage is attached on a side wall of a respective cylinder by an acting force of the prestressing tendon, and the prestressing tendon passes through the prestressing tendon groove on the cylinder of each of the stiffening rods.

3. The prestressed Bailey beam for reinforcement according to claim 1, wherein a prestressing groove, which has an opening at a side and is used to accommodate the prestressing tendon, is formed at a bottom of the lower chord of each of the Bailey panels.

4. The prestressed Bailey beam for reinforcement according to claim 3, further comprising a sealing steel plate and a solidifiable material, a size of the sealing steel plate matches a size of the opening of the prestressing groove, and after the tensioning of the prestressing tendon is completed, the sealing steel plate is fixed on the opening of the prestressing groove, so that the prestressing groove is turned into a tubular structure and the solidifiable material is injected into the tubular structure and is solidified thereinside.

5. The prestressed Bailey beam for reinforcement according to claim 4, wherein the solidifiable material is cement paste or a structural adhesive.

6. The prestressed Bailey beam for reinforcement according to claim 1, wherein the Bailey beam is installed on two sides of the structure to be strengthened, the Bailey beams on the two sides are symmetrically installed, and the anchor bolts pass through the structure to be strengthened and are used to fix the Bailey beams on the two sides.

7. The prestressed Bailey beam for reinforcement according to claim 1, wherein two of the Bailey panels located at a central position of the middle Bailey panel set are respectively provided with female ends and male ends in a prestress stretching direction on a connecting side of the two Bailey panels for mutual connection, the female ends are formed on the upper chord and the lower chord of one of the two Bailey panels, the male ends are formed on the upper chord and the lower chord of the other one of the two Bailey panels, and the female end and a corresponding male end are overlapped and are provided with overlapping elongated sliding grooves for the anchor bolt to pass therethrough.

8. The prestressed Bailey beam for reinforcement according to claim 7, further comprising a plurality of fillers in a same shape as the upper chord and the lower chord, wherein a gap is reserved between one of the stiffening rods and the lower chord of the front Bailey panel, a gap is reserved between the other one of the stiffening rods and the lower chord of the end Bailey panel, and after completion of the tensioning of the prestressing tendon, a corresponding one of the fillers is fixed between the one of the stiffening rods and the lower chord of the front Bailey panel, a corresponding one of the fillers is fixed between the other one of the stiffening rods and the lower chord of the end Bailey panel, and a corresponding one of the fillers is fixed in a gap stretching between the female end and the male end of the two Bailey panels located at the central position of the middle Bailey panel set.

9. The prestressed Bailey beam for reinforcement according to claim 1, wherein aside from a connection part of two of the Bailey panels located at a central position, any two neighboring Bailey panels are respectively provided with female ends and male ends in a prestress stretching direction on a connecting side of the two neighboring Bailey panels for mutual connection, the female ends are formed on the upper chord and the lower chord of one of the two neighboring Bailey panels, the male ends are formed on the upper chord and the lower chord of the other one of the two neighboring Bailey panels, and the female end and a corresponding male end are overlapped and are provided with overlapping fixing holes for a bolt to pass therethrough to fixedly connect the two neighboring Bailey panels.

10. The prestressed Bailey beam for reinforcement according to claim 1, wherein the anchorage includes a tensioning end anchorage and a fixing end anchorage respectively disposed at the two stiffening rods.

11. A construction method adapted for a prestressed Bailey beam for reinforcement, the method comprising the following steps: step 1: providing Bailey panels, anchor bolts and two stiffening rods, wherein the Bailey panels comprise a front Bailey panel, an end Bailey panel, and a middle Bailey panel set; step 2: determining positions of the anchor bolts on a surface of a to-be-reinforced region of a concrete structure, drilling holes and inserting the anchor bolts; step 3: hoisting and mounting the Bailey panels and the stiffening rods to the positions of the anchor bolts, wherein all Bailey panels are linked end-to-end in sequence, the front Bailey panel and the end Bailey panel are installed on both ends of the prestressed Bailey beam respectively, the middle Bailey panel set is installed between the front Bailey panel and the end Bailey panel, the two stiffening rods are disposed on the front Bailey panel and the end Bailey panel respectively, one end of each of the stiffening rods is connected to an upper chord of the front Bailey panel and end Bailey panel respectively through corresponding bolts, each of the anchor bolts passes through a central position of a respective stiffening rod and is fixed on the concrete structure so as to function as a fulcrum for each respective stiffening rod to rotate; and screwing nuts into the anchor bolts while ensuring that the stiffening rods are rotatable and the Bailey panels can slide towards both ends during prestress tensioning; step 4: passing a prestressing tendon through a cylinder of one of the stiffening rods, a lower chord of each of the Bailey panels, and a cylinder on the other one of the stiffening rods, in sequence; performing tensioning on the prestressing tendon by using tension equipment; and after the tensioning is completed, tightening the nuts to fix the stiffening rods and the Bailey panels; and anchoring the prestressing tendon onto the cylinders of the stiffening rods by using a tensioning end anchorage and a fixing end anchorage; step 5: after the prestress tensioning is completed, fixing a filler between one of the stiffening rods and the lower chord of the front Bailey panel, fixing a filler between the other one of the stiffening rods and the lower chord of the end Bailey panel, and fixing a filler between female ends and male ends of two Bailey panels located at a central position, so as to make the Bailey panels and the stiffening rods a fixed whole; and fixing a sealing steel plate on an opening of a prestressing groove so as to form a sealed rectangular steel tube; and step 6: injecting a solidifiable material into the steel tube.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of a Bailey beam installed before prestress tensioning is performed according to the invention;

(2) FIG. 2 is a sectional view taken along line A-A in FIG. 1 according to the invention;

(3) FIG. 3 is a schematic diagram of prestress tensioning and anchoring being completed according to the invention;

(4) FIG. 4 is an overall schematic diagram of a prestressed Bailey beam reinforcing a T beam according to the invention;

(5) FIG. 5 is a sectional view taken along line B-B in FIG. 4 according to the invention;

(6) FIG. 6 is a schematic diagram of all Bailey panels of a prestressed Bailey beam according to the invention, where (a) is a structural diagram of a Bailey panel I, (b) is a structural diagram of a Bailey panel II, (c) is a structural diagram of a Bailey panel III, and (d) is a structural diagram of a Bailey panel IV;

(7) FIG. 7 is a sectional view taken along line C-C in FIG. 6 according to the invention;

(8) FIG. 8 is a sectional view taken along line D-D in FIG. 6 according to the invention; and

(9) FIG. 9 is a structural diagram of a stiffening rod according to the invention.

(10) In the drawings: 1: T beam; 2: Bailey panel I; 3: Bailey panel II; 4: Bailey panel III; 5: Bailey panel IV; 6: Stiffening rod; 601: Cylinder; 7: Bolt; 8: First anchor bolt; 9: Second anchor bolt; 10: Third anchor bolt; 11: Prestressing tendon; 12: Fixing end anchorage; 13: Tensioning end anchorage; 14: Nut; 15: Sealing steel plate; 16: Cement paste; 17: Upper chord; 18: Lower chord; 19: Web member; 20: Male end; 21: Female end.

DESCRIPTION OF THE EMBODIMENTS

(11) Referring to FIG. 1 to FIG. 9, a middle Bailey panel set in this embodiment includes a pair of Bailey panels. In actual use, the middle Bailey panel set may include a plurality of pairs of Bailey panels as needed. For ease of description, a front Bailey panel is referred to as a Bailey panel I 2, an end Bailey panel is referred to as a Bailey panel IV 5, a Bailey panel that is in the middle Bailey panel set and close to the front Bailey panel is referred to as a Bailey panel II 3, and the other Bailey panel is referred to as a Bailey panel III 4. In addition, to be distinguished by name, anchor bolts used to fix stiffening rods, anchor bolts used to fix all Bailey panels, and anchor bolts used to connect two Bailey panels in the middle are respectively referred to as the first anchor bolts 8, the second anchor bolts 9, and the third anchor bolts 10.

(12) The components of the Bailey beam are all prefabricated in a factory, and are assembled and hoisted on site. In FIG. 1 and FIG. 2, the Bailey beam is assembled on site by using bolts and are symmetrically installed on both sides of a structure to be strengthened. In this embodiment, the structure to be strengthened is a T beam. In actual use, the structure to be strengthened may also be a box beam, a rectangular beam, a plate, a wall, or the like. The Bailey panel I 2, the Bailey panel II 3, the Bailey panel III 4, and the Bailey panel IV 5 are connected by using bolts 7 and tightened by using nuts 14. A male end of the Bailey panel II and a female end of the Bailey panel III are both provided with an elongated sliding groove for the third anchor bolt to pass therethrough. The Bailey panel II 3 and the Bailey panel III 4 are connected by using the third anchor bolt 10. The second anchor bolt 9 passes through the elongated sliding grooves on all Bailey panels and anchors the Bailey panels onto the T beam 1. The stiffening rod 6 functions as a lever to transmit the prestress, is provided with a screw hole for the bolt 7 to pass therethrough, and is connected to female ends 21 of the Bailey panel I 2 and the Bailey panel IV 5 by using the bolts 7. The first anchor bolt 8 passes through the screw hole in the middle of the stiffening rod 6 and anchors the stiffening rod 6 onto the T beam 1. During prestress tensioning, the first anchor bolt 8 functions as a fulcrum of a lever, and a lower end of the stiffening rod 6 is a cylinder 601 provided with an elongated sliding groove. The prestressing tendon 11 passes through a cylinder 601 on one end of the stiffening rod 6, a lower chord 18 of the Bailey panel, and a cylinder 601 on the other end of the stiffening rod 6. In FIG. 3 to FIG. 5, the prestressing tendon 11 is tensioned by a jack, and is anchored onto the cylinder 601 on the lower end of the stiffening rod 6 by using a fixing end anchorage 12 and a tensioning end anchorage 13. During prestress tensioning, the tensioning end anchorage and the fixing end anchorage can slide along an outer wall of the cylinder 601, enabling the prestressing tendon 11 to keep a shape of a straight line. After the prestress tensioning is completed, the Bailey beam is fixed by tightening nuts 14 and is anchored onto the T beam 1. H-shaped steels serving as fillers are fixed respectively between the cylinder 601 of the stiffening rod 6 and the lower chord 18 of the Bailey panel I, between the cylinder 601 of the stiffening rod 6 and the lower chord 18 of the Bailey panel IV, and between the female end 21 of the Bailey panel III 4 and a chord of the Bailey panel II 3 by means of welding. A sealing steel plate 15 is welded onto an opening of the prestressing groove on the lower chord 18 of the Bailey panel so as to form a sealed rectangular steel tube. Finally, the cement paste 16 is used as a solidifiable material, which is injected into the steel tube so as to form a composite structure of the prestressed concrete filled steel-tubular.

(13) The Bailey beam slides towards both ends during prestress tensioning. After the tensioning is completed, the anchor bolts are tightened so as to anchor the Bailey beam onto the structure to be strengthened. Then the H-shaped steels serving as fillers are welded respectively between the cylinder of the stiffening rod and the lower chord of the Bailey panel I, between the cylinder of the stiffening rod and the lower chords of the Bailey panel IV, and onto the female end of the Bailey panel III. During the prestress tensioning, the stiffening rod is driven to rotate around the first anchor bolt, transmit the prestress to the Bailey beam and drive the Bailey beam to slide towards both ends. Then the Bailey beam turns the prestress into a vertical force and transmits the vertical force to the structure through the anchor bolts.

(14) The Bailey beam includes an even number of Bailey panels, and the number is no less than 4. The Bailey panels are symmetrically arranged along a center of the reinforced region. The specific number and size of the Bailey panels should be based on the size of the reinforced structure and the range of the reinforced region. In this embodiment, the Bailey panel uses an H-shaped steel rather than a channel steel as an upper chord and a lower chord, so as to form a prestressing tendon groove.

(15) The prestressing tendon is arranged in the lower chord. After the prestress tensioning is completed, a sealing steel plate is welded at a lower side of the H-shaped steel and a grouting port is reserved. Then cement paste or a structural adhesive is injected so as to form a composite structure of the prestressed concrete filled steel-tubular. In this case, the Bailey beam and the prestressing tendon bear weight jointly, stiffness of the components is enhanced, a prestress loss is reduced, and the prestressing tendon is protected.

(16) After tensioning is completed, the prestressing tendon implements self-anchorage on the cylinder of the stiffening rod and does not cause local cracking of the concrete member.

(17) The specific working process is shown as follows. Step 1: Prefabricate the Bailey panel I 2, the Bailey panel II 3, the Bailey panel III 4, the Bailey panel IV 5, and the stiffening rods 6 in a factory. Step 2: Determine positions of the anchor bolts on a surface of the reinforced region of the T beam 1, drill holes and insert the anchor bolts. Step 3: The prefabricated Bailey panels and the stiffening rods 6 are assembled at the construction site by using the bolts 7, and hoisted in place by using hoisting equipment, where the first anchor bolt 8 passes through the screw hole in the middle of the stiffening rod 6 and functions as a fulcrum of a lever, the second anchor bolt 9 passes through the elongated sliding groove on the upper chord 17 and the lower chord 18 of the Bailey panel, the third anchor bolt 10 passes through the male end 20 of the Bailey panel II 3 and the female end 21 of the Bailey panel III 4, and the nuts 14 are not excessively tightened, so as to ensure that the stiffening rod 6 can rotate and the Bailey frame can slide towards both ends during the prestress tensioning. Step 4: Pass the prestressing tendon 11, and perform tensioning and anchoring by using the jack and the anchorages, so that during the prestress tensioning, the stiffening rod 6 rotates around the first anchor bolt 8, transmits the prestress to the Bailey beam and drives the Bailey beam to slide towards both ends, and then turns the prestress into a vertical force and transmits the vertical force to the structure by using the anchor bolts. The force transmission path is: the anchorages.fwdarw.the stiffening rods.fwdarw.the first anchor bolt and the Bailey beam.fwdarw.the second anchor bolt and the third anchor bolt.fwdarw.the T beam. Step 5: After the prestress tensioning is completed, fix the Bailey beam by tightening the nuts 14, anchor the Bailey beams onto the T beam 1, and then weld the H-shaped steel and the sealing steel plate 15, so that a sealed rectangular steel tube is formed at the lower side of the H-shaped steel of the lower chord 18 of the Bailey beam. Step 6: Inject the cement paste 16 or the structural adhesive into the steel tube.

(18) The foregoing descriptions are merely for illustration of the invention, but are not intended to limit the technical solution in the invention. Any improvement, replacement, or the like made within the principle of the invention shall fall within the protection scope of the invention.