基于時(shí)變可靠度的銹蝕混凝土結(jié)構(gòu)全壽命成本模型

陸春華+袁思奇

摘要：為了分析混凝土結(jié)構(gòu)在氯鹽環(huán)境下的全壽命周期成本，基于現(xiàn)有氯離子擴(kuò)散模型和裂縫寬度預(yù)測(cè)模型，采用MATLAB軟件進(jìn)行Monte-Carlo抽樣模擬，建立結(jié)構(gòu)失效概率與可靠度指標(biāo)的擬合公式。通過研究維護(hù)-加固措施對(duì)可靠度指標(biāo)的影響，建立全壽命周期內(nèi)維護(hù)-加固費(fèi)用計(jì)算評(píng)估方法，并以混凝土橋梁結(jié)構(gòu)為例計(jì)算了全壽命周期維護(hù)-加固成本。結(jié)果表明：失效概率與可靠度指標(biāo)可用以失效概率等于0.1為界的分段函數(shù)進(jìn)行描述；維護(hù)-加固效果持續(xù)時(shí)間對(duì)結(jié)構(gòu)構(gòu)件服役年限延長(zhǎng)的影響最顯著；當(dāng)保護(hù)層厚度取60 mm時(shí)，維護(hù)-加固階段費(fèi)用有明顯下降，較保護(hù)層厚度取40 mm時(shí)減少25%～50%。

關(guān)鍵詞：混凝土結(jié)構(gòu)；氯鹽侵蝕；銹脹裂縫寬度；時(shí)變可靠度；全壽命成本

中圖分類號(hào)：TU375 文獻(xiàn)標(biāo)志碼：A

文章編號(hào)：1673-2049（2017）02-0071-08

Abstract：In order to analyze the life-cycle cost of concrete structures in chloride environment， the existing chloride diffusion model and crack width prediction model were used， Monte-Carlo sampling simulation was carried out using MATLAB software， and the fitting formula of structural failure probability and reliability index was established. The calculation method of maintenance-reinforcement cost in the whole life cycle was established combining the influence of maintenance-reinforcement measures on reliability index， and the life-cycle maintenance-reinforcement cost was calculated by taking concrete bridge structure as an example. The results show that the failure probability and reliability index can be described by piecewise function with failure probabilities being 0.1 as boundary. The duration of maintenance-reinforcement effect has the most obvious effect on service life extension of structural members. When the thickness of protective layer is 60 mm， the maintenance-reinforcement cost decreases obviously， and is reduced by 25%-50% compared with the thickness of protective layer 40 mm.

Key words：concrete structure； chloride erosion； corrosion crack width； time-varying reliability； life-cycle cost