JPH03151403A - Reinforcing method for existing bridge girder - Google Patents

Abstract

PURPOSE:To facilitate reinforcement by inserting tension materials in brackets projected on both sides of a middle portion of an existing bridge girder to be laid between both ends of the bridge girder, and tensing the tension materials to fix at least one end to bridge piers or abutments on both outsides of the bridge girder. CONSTITUTION:Brackets 3 are projected on both sides below the middle portion of a girder G, and tension materials 1 inserted in the brackets 3 are fixed to bridge piers P or abutments A positioned on both sides of the bridge girder higher than the brackets 3. Tension is given to the tension materials 1 to introduce the vertical upward components of tension as push-up force into the bridge girder G. Accordingly, tension materials can be fixed surely and easily without damaging the existing bridge girder.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for reinforcing an existing bridge girder by introducing prestress into the existing bridge girder.

(Problem to be solved by the invention) Repairing existing bridge girders by adding prestress,
Alternatively, in the case of reinforcement, tendons are placed on both outside sides of the bridge girder, but the ends thereof are conventionally generally anchored to the bridge girder itself to be reinforced.

However, the ends of the bridge girder were already crowded with reinforcing bars, PC cables, and fixing devices for fixing them, which were placed during the construction of the bridge girder, so it was necessary to avoid these parts and re-fix the tension material here. It is extremely difficult to do so, and even if it were possible to fix it, there is a risk of damaging the bridge girder.

This invention was made based on this problem with the conventional method, and aims to propose a new method for reinforcing bridge girders without damaging them.

(Means for Solving the Problems) The present invention solves the problems of the conventional methods by fixing the ends of tendons to bridge piers or abutments from which bridge girders have been removed.

The tension material is inserted into brackets protruding from both sides of the intermediate portion of the bridge girder, stretched between both ends of the bridge girder, and at least one end is fixed to the piers and abutments on both sides of the bridge girder.

(Example) The present invention will be explained below based on the drawings showing one embodiment.

This invention is a method of reinforcing an existing bridge girder G, which is constructed between piers P or abutments A, with tension members 1 placed on both outer sides thereof, as shown in FIG.

In the figure, reference numeral 2 denotes a tension member that prestresses the bridge girder G in advance, and is fixed to the end of the bridge girder G as shown in FIG.

In the case of the simple girder shown in the example, the tendons 1 are as shown in Fig. 1-■
, as shown in FIG. 4, is inserted into a bracket 3 protruding from both sides of the bridge girder G, and is disposed below the middle part of the bridge girder G.
It is fixed to the piers P and abutments A located on both sides of the bridge girder G at a higher position than the bracket 3, as shown in FIG. 1-H.

In the embodiment shown in FIG. 1, both ends of the tendon 1 are connected to piers P.

Or it is fixed on abutment A.

In this embodiment, as shown in FIG. 1-2, the vertically upward component of the tension applied to the tendon 1 is introduced into the bridge girder G as a pushing force.

When the tension members 1 are arranged in a polygonal manner as in the example shown here, the vertically upward stress introduced into the bridge girder G by the tension members 1 is due to the difference in height between the bracket 3 at the middle of the bridge girder G and the anchoring point. Therefore, as shown in FIG. 5, by installing a saddle 4 below the middle part of the bridge girder G and protruding the bracket 3 from this, the pushing force against the bridge girder G can be increased.

In the embodiment shown in FIG. 2, one end of the tendon l is fixed to the end of the bridge girder G at approximately the same position as the existing tendon 2, and the other end is fixed to the pier P or the abutment A.

In this embodiment, one end of the tension member 1 is fixed to the movable shoe side of the bridge girder G, so that a compressive force is applied to the bridge girder G in addition to the above-mentioned upward force.

In the above embodiment, the case where the bridge girder G is a statically fixed structure, that is, a simple girder, has been shown, but the above procedure can also be applied to the case of a continuous girder, etc., which is a statically fixed structure.

(Effects of the Invention) This invention is as described above, and since at least one end of the tendon is fixed to the piers or abutments on both sides of the bridge girder, the ends of the tendon can be easily and reliably fixed. , it is also possible to reinforce existing bridge girders without damaging them.

[Brief explanation of the drawing]

Figures 1 and 2 are elevational views showing embodiments of the present invention;
0 is a cross-sectional view showing the fixing portion of the tendon material, and FIGS. 4 and 5 are cross-sectional views showing the protruding position of the bracket. P... Pier, A... Abutment, G...
...Bridge girder, 1...Tension material, 2...Tension material, 3...Bracket, 4...Saddle.

Claims (1)

[Claims] (1) Bridge piers or existing bridge girders installed between bridge abutments,
Brackets are provided protruding from both sides of the intermediate part, tension members are inserted through these brackets and stretched between both ends of the bridge girder, and the tension members are tensioned so that at least one end of the tension members is connected to the piers on both outside sides of the bridge girder.
Or a reinforcement method for existing bridge girders anchored to the abutment.