The paper presents a series of impact experiments performed on reinforced concrete (RC) beams with and without stirrups and additionally without and with lateral strengthening layers made of two types of strain-hardening cement-based composites (SHCC). The impact tests were performed in an advanced drop tower facility with accelerated steel projectiles. Four impact velocities were applied, ranging from 17 m/s to 30 m/s, corresponding to kinetic energies from 2.1 kJ to 6.4 kJ. The difference among the 20 mm-thick, normal-strength SHCC layers with 2 % fiber volume content consisted in the type of reinforcing fiber: polyvinyl alcohol (PVA) or ultra-high molecular weight polyethylene (UHMWPE). The RC beams with no shear reinforcement yielded shear failure with displaced punching cones under all impact velocities. The stirrups notably increased their impact resistance and damage extent, allowing multiple impact loads without structural collapse. The lateral strengthening layers of SHCC substantially increased the load-bearing capacity, diminished the damage extent, and increased the damage tolerance under repeated impact events of the RC beams both with and without stirrups, proving to be a promising strengthening solution for existing structures prone to severe mechanical loading.

本文介绍了对带箍筋和不带箍筋的钢筋混凝土 (RC) 梁以及由两种应变硬化水泥基复合材料 (SHCC) 制成的不带和带横向加强层的钢筋混凝土 (RC) 梁进行的一系列冲击实验。冲击测试是在配备加速钢弹的先进落塔设施中进行的。应用四种冲击速度，范围从 17 m/s 到 30 m/s，对应的动能从 2.1 kJ 到 6.4 kJ。20毫米厚、纤维体积含量为2%的正常强度SHCC层之间的差异在于增强纤维的类型：聚乙烯醇（PVA）或超高分子量聚乙烯（UHMWPE）。没有抗剪钢筋的 RC 梁在所有冲击速度下都会因冲孔锥体移位而产生剪切破坏。马镫显着提高了其抗冲击性和损坏程度，允许多重冲击载荷而不会导致结构倒塌。SHCC的横向加强层显着提高了承载能力，减少了损坏程度，并提高了带箍筋和不带箍筋的RC梁在重复冲击事件下的损坏容限，事实证明，对于容易发生应力腐蚀的现有结构来说，这是一种有前景的加固解决方案。严重的机械负载。