Method for reinforcing box girder by pre-stress shear-resistance

Abstract

The invention provides a method for reinforcing a box girder by pre-stress shear-resistance. Anchorage blocks are correspondingly installed on both sides of a web plate of a box chamber of the box girder up and down, a shear-resistance bar is temporarily fixed between the two anchorage blocks; a precast open type electromagnetic heating coil is used for wrapping the periphery of the shear-resistance bar, and the electromagnetic heating coil is connected with a heating main machine; and a high-frequency magnetic field generated by variable-frequency power supply enables the shear-resistance barto carry out self-heating rapidly, a temperature control device controls the electromagnetic heating temperature, a displacement meter controls the elongation of the shear-resistance bar, and at thesame time, two ends of the shear-resistance bar are anchored by an anchorage, so that the disposal of the pre-stress shear-resistance reinforcement box girder is achieved. According to the method forreinforcing box girder by pre-stress shear-resistance, the initiative is strong, the cracking load of the web plate of the box girder is effectively improved, and the shear-resistance bearing capacityof the web plate is improved; and through the novel construction process, large tensile equipment is not required, the operation is simple, easy control is achieved, the accuracy is high, the safetyis high, and the construction efficiency is greatly improved.

Description

technical field [0001] The invention belongs to the field of civil engineering, and in particular relates to a bridge reinforcement technology, in particular to a prestressed shear reinforcement method for a box girder. Background technique [0002] The oblique cracks of the box girder web are one of the main cracks produced by the prestressed box girder, especially 45° oblique cracks will appear on the webs on both sides near the end of the side-span cast-in-place box girder, making the box girder The shear resistance, torsion resistance, spanning capacity and even structural bearing capacity of the overall structure decrease. Therefore, the problem of bridge reinforcement is becoming more and more prominent. The existing box girder shear reinforcement technologies include the method of pasting steel plates, increasing the inner section of the web, and strengthening with external prestressed tendons. [0003] Chinese patent authorization publication number: CN 101230562A d...

AI Technical Summary

Problems solved by technology

The disadvantage of this invention is that the steps are complicated, the construction difficulty is high, and the construction efficiency is low, especially when the prestressed bundle is stretched in the box chamber, the tension space problem is not considered, and the tension efficiency is low. Reinforcement, although effective reinforcement can be achieved, but it affects the appearance. If the inner section of the web is increased, the self-weight of the box girder will be increased, which will affect the use

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