钢筋混凝土深梁在冲击荷载作用下的动力响应分析

Analysis on Dynamic Response of RC Deep Beam under Impact Load

为了研究钢筋混凝土深梁的抗冲击性能,在已有试验的基础上,建立了与试验结果吻合良好的数值模型,验证了钢筋混凝土模型的合理性。研究了不同冲击速度、混凝土强度和冲击位置等因素的影响,分析了冲击力时程曲线、跨中位移、剪力响应和破坏模式。结果表明:钢筋混凝土深梁在冲击荷载下的破坏形态、冲击力和位移响应等与试验结果相近,较好地再现了破坏过程,在冲击荷载作用下,由于冲击的能量不同、结构自身属性的区别和接触刚度的差异,钢筋混凝土在冲击荷载下的冲击力时程曲线具有明显的区别;冲击速度的不同明显影响梁的塑性分布趋势,随着冲击速度的增大,梁的损失程度逐渐增大,且裂缝分布也逐渐密集;随着混凝土强度的增大,沿着长度方向分布的剪力逐渐增大;深梁的破坏模式都为弯剪破坏,但是随着冲击速度的增大,梁的破化模式受剪力影响更加明显;跨中峰值位移和残余位移受到冲击能量影响较大,并且峰值位移与冲击能量呈现线性关系;混凝土强度提高有助于减小跨中的峰值位移和残余位移,且梁的损伤程度逐渐下降;在跨中冲击荷载下,梁的剪力响应呈现对称分布规律,形成了跨中高剪力作用;冲击位置靠近支座,深梁的损伤程度逐渐下降。

In order to study the impact resistance of reinforced concrete deep beam,on the basis of the existing test,a numerical model which is in good agreement with the experimental result is established,the rationality of the reinforced concrete model is verified.The influences of different impact velocity,concrete strength and impact location are studied,and the impact force time-history curve,mid-span displacement,shear response and failure mode are analyzed.The result shows that(1) The failure form,impact force and displacement response of the reinforced concrete deep beam under impact load are similar to the test result,and the failure process is well reproduced.Under the impact load,due to the difference of the impact energy,the difference of the structure’s own properties and the difference of the contact stiffness,the time-history curves of the impact force of the reinforced concrete under the impact load are obviously different.(2) The different impact velocities obviously affect the plastic distribution trend of the beam.With the increase of impact velocity,the loss degree of the beam increases gradually,and the crack distribution becomes denser.(3) With the increase of concrete strength,the shear forces along the length direction increase gradually.(4) The failure modes of deep beam are flexural shear failure,but with the increase of impact velocity,the failure mode of beam is more obviously affected by shear force.(5) The peak displacement and residual displacement at mid-span are greatly affected by impact energy,and the relationship between peak displacement and impact energy is linear.(6) The increase of concrete strength helps to reduce the peak displacement and residual displacement at mid-span,and the damage degree of beam decreases gradually.(7) Under the mid-span impact load,the shear response of the beam presents symmetrical distribution,and it forms the mid-span high shear force.(8) When the impact location close to the support,the damage degree of the deep beam gradually decreases.