Abstract This paper examines the influence of reinforcement detailing and fibers on the static and blast performance of beams built with high-strength concrete (HSC) and high-strength (HS) steel reinforcement. The beams in this study had dimensions of 125 mm × 250 mm × 2440 mm (b × d × L), and were built with HSC and Grade 690 MPa ASTM A1035 reinforcement. Longitudinal reinforcement in tension consisted of either 2-No.4 or 2-No.5 high-strength bars (ρ = 1% or 1.5%), while transverse reinforcement consisted of closed ties or open-stirrups made from 6 mm wire arranged at various spacing (s). Group A beams (6 specimens) were designed according to modern blast standards, with top continuity bars and closely spaced ties at s = 50 mm (d/4) throughout the beam span, while Group B beams (2 specimens) were designed with high-strength fiber-reinforced concrete (HSFRC) and a larger tie spacing of s = 100 mm (d/2). The performance of the beams is compared to that of a control set of singly-reinforced beams with “nominal detailing” consisting of open-stirrups spaced at s = 100 mm (d/2) in the shear spans only - Group C. Blast tests were conducted using a shock-tube with companion beams tested under quasi-static four-point bending. The use of blast detailing in Group A is found to significantly enhance the ductility of the high-strength steel reinforced concrete beams under static loading, allowing for full utilization of the high-strength bars in tension. Improved detailing also leads to important enhancements in blast behavior, including better control of displacements, increased blast capacity and high damage tolerance when compared to the Group C control specimens. Moreover, the results from Group B demonstrate that fibers can be used to relax transverse steel detailing without compromising ductility or performance under both static and blasts loads. The ability of high-strength steel to reduce steel requirements is also demonstrated. Moreover, the post-blast performance of the beams is assessed through residual static testing of the blast-damaged beams. The results show that blast detailing and fibers allow for significant residual post-blast resistance and energy-absorption capacity. As part of the analytical study the blast response of the test beams is predicted using 2D finite element (FE) modelling. The results show that the FE procedure which employed the Disturbed Stress Field Model was able to accurately capture the peak load and failure mode of the beams under static conditions. Under blast loading, the model also captured the displacement response of the beams up to first peak, however the accuracy reduced at subsequent cycles, with the results found to be sensitive to the choice of damping coefficients.

中文翻译：

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细部对高强度钢筋混凝土 (HSS-RC) 梁爆炸和爆炸后回弹的影响

摘要 本文研究了钢筋细节和纤维对用高强度混凝土 (HSC) 和高强度 (HS) 钢筋建造的梁的静力和爆破性能的影响。本研究中的梁尺寸为 125 mm × 250 mm × 2440 mm (b × d × L)，采用 HSC 和 690 MPa ASTM A1035 增强材料建造。受拉纵向钢筋由 2-No.4 或 2-No.5 高强度钢筋（ρ = 1% 或 1.5%）组成，而横向钢筋由由 6 mm 钢丝制成的闭合拉杆或开口箍筋组成，布置在各种间距（s）。A 组梁（6 个试样）是根据现代爆破标准设计的，在整个梁跨度上具有 s = 50 mm (d/4) 的顶部连续杆和紧密间隔的拉杆，而 B 组梁（2 个试件）采用高强度纤维增强混凝土 (HSFRC) 和更大的拉杆间距 s = 100 mm (d/2) 设计。梁的性能与“标称细部”由仅在剪切跨距中间隔 s = 100 mm (d/2) 的开箍筋组成的“标称细部”控制组的性能进行比较 - C 组。 爆破试验使用带有在准静态四点弯曲下测试的伴随梁的冲击管进行。发现在 A 组中使用爆破细节可以显着提高高强度钢筋混凝土梁在静载荷下的延展性，从而充分利用受拉的高强度钢筋。改进细节还导致爆炸行为的重要增强，包括更好地控制位移，与 C 组对照样品相比，增加了爆炸能力和高损伤容限。此外，B 组的结果表明，纤维可用于松弛横向钢细部，而不会影响静态和爆炸载荷下的延展性或性能。还展示了高强度钢降低钢材需求的能力。此外，梁的爆炸后性能是通过对爆炸损坏梁的残余静力测试来评估的。结果表明，爆炸细节和纤维允许显着的残余爆炸后阻力和能量吸收能力。作为分析研究的一部分，使用二维有限元 (FE) 建模来预测测试梁的爆炸响应。结果表明，采用扰动应力场模型的有限元程序能够准确地捕捉到梁在静态条件下的峰值载荷和破坏模式。在爆炸载荷下，该模型还捕获了梁的位移响应直到第一个峰值，但是在随后的循环中精度降低，结果发现对阻尼系数的选择很敏感。