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建立了采用传统竖向预应力技术的箱梁桥腹板主拉应力随时间变化模型,考虑混凝土强度、螺纹钢强度等参数的时变性和随机性,以腹板内主拉应力达到容许应力限值为极限状态,发展了采用传统预应力张拉工艺的箱梁桥腹板开裂概率模型。基于Monte-Carlo模拟方法,计算了服役期内腹板开裂风险,并对相关参数进行敏感性分析。研究表明在本文设计参数条件下,设计使用年限内的腹板最大开裂风险概率为1.49%;敏感性分析表明精轧螺纹钢筋纵向间距和锚具变形与钢筋回缩对腹板开裂影响最大;安装偏差角度次之;箍筋数量对腹板开裂风险影响最小。
The model of the main tensile stress with time of the webs of the box girder bridge adopting the traditional vertical prestressing technology is established. Considering the time-varying and randomness of parameters such as concrete strength and rebar strength, the allowable stress limit The value of the limit state, the development of traditional prestressed tensioning process of web girder bridge cracking probability model. Based on the Monte-Carlo simulation method, the risk of web cracking during service is calculated, and the sensitivity of the relevant parameters is analyzed. The results show that under the condition of design parameters, the probability of maximum cracking of the web is 1.49% within the design service life. Sensitivity analysis shows that the longitudinal spacing of the rebar and the deformation of the anchorage have the greatest effect on the web cracking. The deviation angle is second; the quantity of stirrups has the least influence on the risk of web cracking.