起波配筋RC梁抗爆作用机理及抗力动力系数的理论计算方法

针对钢筋混凝土(RC)梁,提出了一种通过对抗拉纵筋进行局部弯折,形成钢筋起波,从而提高RC梁抗爆能力的高效新方法。结合已有的实验结果和有限元模型计算,分析了起波配筋RC梁的受荷破坏全过程,揭示了其抗爆作用机理。分析结果表明,在RC梁底部适当位置设置纵筋起波,能增大RC梁在爆炸荷载作用下的允许变形,有效吸收爆炸能量,大幅度提高RC梁的抗爆性能。基于能量法,建立了起波配筋RC梁在爆炸荷载作用下的理论计算模型,给出了抗力动力系数的显示计算公式;讨论了平屈抗力比、平弹变形比以及屈弹变形比3个关键设计参数对起波配筋RC梁抗爆性能的影响规律,以便为进一步工程应用提供理论依据。

Blast-resistant mechanism of RC beam with kinked rebar and calculation method of dynamic resistance coefficient

To improve the blast resistance of reinforced concrete (RC) beam, an efficient design method was proposed that bending the longitudinal bar as a wave at an appropriate location in the beam. Combing the experimental results and calculation of finite element model, the damage process of the RC beam with local kinked rebar was found, and the mechanism of blast resistance was revealed. Analytical results indicated that the kinked rebar can increase the allowable deformation of the RC beam under blast loads, effectively absorbing the explosive energy and greatly improving the blast-resistant performance. A theoretical method was developed to calculate the blast resistance of the RC beam with local kinked rebar under blast loads, on base of the energy method. Explicit formulae of the dynamic resistance coefficient were derived. The influences of three key design parameters, e.g. the bearing capacity ratio of platform period to yielding period, the deformation ratio of platform period to elastic period and the deformation ratio of yielding period to elastic period, on the blast resistance of RC beam with local kinked rebar were discussed. It provides a theoretical basis for further engineering application.