基于全寿命周期的混凝土梁式桥设计探讨

Design of Concrete Beam Bridge Based on Full Life Cycle

针对桥梁结构典型的碳化腐蚀病症,提出了一种基于桥梁典型失效模式下的结构全寿命周期控制方法,从桥梁腐蚀失效角度对碳化病症全周期的失效概率进行分析,并给出了桥墩全寿命周期的成本控制策略。研究结果表明:钢筋开始锈蚀概率随保护层厚度的增加而降低,随水灰比的下降而下降,当保护层厚度大于45mm,满足全寿命周期内桥墩钢筋设计使用需求;保护层厚度越大,钢筋开裂允许概率越大。随裂缝宽度的减小,保护层严重开裂概率明显上升;在忽略桥梁大型维修和更换成本和社会成本条件下,贴现率0%～1%时,通过在桥墩内钢筋位置涂装环氧树脂能有效降低桥梁全寿命设计成本;贴现率2%～7%时,通过在混凝土表面采用阻隔剂涂层施工工艺能有效降低成本。

In view of the bridge structure of typical carbonization corrosion condition,put forward a kind of typical failure mode based on bridge structure of the full life cycle control method,carbonization conditions from the Angle of bridge corrosion failure of the whole cycle of failure probability analysis,and gives the bridge whole life cycle cost control strategy.The results show that the reinforced began corrosion probability decreased with increasing the thickness of protective layer,along with the water cement ratio falls,when the cover thickness is more than 45 mm,meet the demand of pier reinforcement design using the whole life cycle;The greater the thickness of the protective layer,the greater the probability of the reinforcement cracking.With the decrease of crack width,the probability of serious cracking of protective layer increases obviously.Under the condition of ignoring the large repair and replacement cost and social cost of the bridge,the discount rate is 0%to 1%,which can effectively reduce the cost by adopting the barrier coating construction technology on the concrete surface.When the interest rate is 0%to 1%,the design cost of the bridge can be effectively reduced by applying epoxy resin to the steel position in the bridge pier.