| Slab bridge is one of the most common forms of bridge structure in highway. With the increase of traffic and the role of a large number of overweight vehicles, combined with the design and construction of some unreasonable places, the slab after long time operation, appeared a variety of different degree of disease.This paper systematically summarizes the research status quo of bridge reinforcement technology, reinforced concrete and prestressed concrete slab bridge disease cause, all kinds of reinforcement technology and the corresponding calculation theory, expounds the characteristics of the bridge reinforcement stress in stages.Is proposed in this paper to separate reinforcing properties, clear reinforcement purpose, pay attention to a variety of strengthening technical renovation and comprehensive utilization of bridge design principle, made a detailed introduction of prestressed reinforcement system, finally to span of 12 m reinforced concrete hollow slab bridge as an example, for the process with prestressed reinforcement method and made some analysis to common problems.By summing up analysis, for the hollow slab bridge reinforcement scheme selection is given the following advice:(1) for the original bridge hollow slab bottom Revere transverse cracks, the bending bearing capacity is insufficient, and the serious situation of concrete carbonation, unbond prestressed reinforcement scheme should be preferred.Use is anchored in reinforced beam body on small diameter prestressed concrete, prestress of beam body, and then injection of high performance composite mortar bonded prestressed reinforcement scheme, normal section of the hollow slab bridge reinforcement, can significantly improve the bearing capacity of normal section flexural plate. After injection of the composite mortar layer can protect the steel from corrosion and improve the durability of the structure, bearing capacity and durability of reinforcement is obtained a double purpose. In addition, because after the injection of the composite mortar layer increased the original beam section size, increased the cross-section stiffness, also help to solve the problems of large deformation.(2) of the original bridge damaged serious condition, should be combined with bridge deck pavement maintenance, first consider the enlarging section method is adopted for compressive zone of the hollow slab (thickening bridge panel). Combination of bridge deck pavement maintenance, appropriately increase the surfacing layer thickness, and consider new thickening of bridge deck pavement in hollow slab work together, increase the effective height of beam, can improve the flexural bearing capacity of the beam.(3) the structure of the slabs was high beam is small, the original beam reinforcement ratio is opposite bigger, due to the limitation of the original beam deformation, under the limit state after the reinforcing material is more difficult to play a role, after the reinforcing material to the strain (stress) lag caused by a variety of adverse effects will become more prominent. Therefore, direct pasting steel plate or high-strength fiber composite materials for strengthening of slabs is inappropriate. |
