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A control method for pre-camber value of pre-tensioned reinforced concrete prestressed bridge slab
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A reinforced concrete and control method technology, applied in bridges, bridge materials, bridge construction, etc., can solve problems affecting the stiffness of the bridge deck, increase the impact of vehicles, and large deflection at the bottom of the bridge deck, so as to ensure the quality of use, The effect of prolonging the service life and being easy to popularize and apply
Active Publication Date: 2018-03-20
薛秋香
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Problems solved by technology
Excessively large pre-camber values will affect the stiffness of the bridge deck, increase the impact of vehicles, cause severe vibration of the bridge, and reduce the service quality and life of the bridge; at the same time, due to excessive pre-camber values, the bridge deck may Insufficient pavement thickness leading to premature failure of the bridge deck pavement
When the pre-camber value is less than the design pre-camber value, it is easy to cause excessive deflection at the middle bottom of the bridge slab, which will lead to concrete cracks due to tension, which will cause corrosion of prestressed tendons and steel bars, resulting in damage to the entire component and even the entire bridge superstructure
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Embodiment 1
[0032] The prefabrication plant makes 20m90° reinforced concrete prestressed hollow bridge slabs. The prefabrication plant has 4 prefabricated slots, the length of which is 64m.
[0033] Design indicators: the concrete grade is C50, and the standard strength is 1860MPa φ j 15.24mm steel strand, all 14 steel strands are in one layer, the tensile stress is 1395MPa, and the design pre-camber value is 40mm.
[0034] After testing, the compressive strength of epoxy resin mortar and epoxy resin concrete 1d is not less than 45MPa.
[0035] Such as figure 1 As shown, a method for controlling the pre-camber value of a pre-tensioned reinforced concrete prestressed bridge slab includes the following steps:
[0036] Step 1: Select the prestressed steel strand from the pre-tensioning method to the post-tensioning method:
[0037] According to the following selection principles, it is determined to change the originally designed pre-tensioned prestressed steel strands to post-tensioned p...
Embodiment 2
[0072] The prefabrication plant makes 30m 90° reinforced concrete prestressed hollow bridge slabs. There are 4 prefabricated troughs in the prefabrication plant, and the length of the prefabricated troughs is 64m. 102d Transportation and installation after prefabrication of planned bridge slab.
[0073] Design indicators: the concrete grade is C50, and the standard strength is 1860MPa φ j 15.24mm steel strand, all 18 steel strands are in one layer, the tensile stress is 1395Mpa, and the design pre-camber value is 40mm.
[0074] After testing, the compressive strength of epoxy resin mortar and epoxy resin concrete 1d is not less than 45MPa.
[0075] Such as figure 2 As shown, a method for controlling the pre-camber value of a pre-tensioned reinforced concrete prestressed bridge slab includes the following steps:
[0076] Step 1: Select the prestressed steel strand from the pre-tensioning method to the post-tensioning method:
[0077] According to the following selection p...
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Abstract
The invention relates to the technical field of roads and bridges, in particular to a method for controlling the precamber value of a pre-tensioning method reinforced concrete prestressed bridge plate. The method comprises the following steps: selecting three or four pre-tensioning method prestressed steel strands, modifying the three or four pre-tensioning method prestressed steel strands into post-tensioning method prestressed steel strands, and ensuring transverse symmetric distribution; reserving post-tensioning method prestressed steel strands for standby application, if the span of the bridge plate is equal to or smaller than 20 m, reserving two post-tensioning method prestressed steel strands; if the span of the bridge plate is larger than 20 m, reserving four post-tensioning method prestressed steel strands; arranging metal bellows and anchorage device base plates; during construction of the post-tensioning method prestressed steel strands, when the post-tensioning method prestressed steel strands are stretched and drawn, increasing the load step by step in a grading manner, sustaining the load for 2-5 minutes if one grade of load is increased, and then measuring the precamber value of the bridge plate until the precamber value of the bridge plate meets the requirements; carrying out mud jacking and anchorage sealing. According to the invention, the purpose of accurately controlling the precamber value of the pre-tensioning method reinforced concrete prestressed bridge plate is realized through the post-tensioning method so as to improve the quality and prolong the service life of the bridge.
Description
technical field [0001] The invention relates to the technical field of roads and bridges, in particular to a method for controlling the pre-camber value of pretensioned reinforced concrete prestressed bridge slabs. Background technique [0002] Pretensioned reinforced concrete prestressed bridge slabs are widely used because of their large spanning capacity, simple structure and stress, convenient construction, mass prefabrication, and low cost. [0003] Pre-tensioned reinforced concrete prestressed bridge slab prefabrication factories generally have multiple prefabricated grooves, and each prefabricated groove can produce multiple bridge slabs. The so-called pre-tensioning method is to stretch all the steel strands to the design tensile stress before pouring concrete. The tensile stress of each steel strand is the same, and then pour concrete, and then the concrete is cured and released when the strength meets the requirements. Due to the bending moment generated by the ec...
Claims
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Application Information
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