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摘要: 采用數值仿真技術建立了足尺鋼筋混凝土墩柱精細有限元模型, 分析了側向沖擊荷載下墩柱的動態響應和抗沖擊性能, 提出了一種基于截面損傷因子的損傷評估方法, 討論了不同碰撞參數對鋼筋混凝土墩柱破壞模式和損傷機理的影響.結果表明: 沖擊荷載下鋼筋混凝土墩柱的耗能主要分為接觸區域局部耗能和構件整體耗能; 當沖擊體的初始動能恒定時, 沖擊質量和沖擊速度的不同組合會導致鋼筋混凝土墩柱損傷破壞機理的顯著差異; 基于截面損傷因子的損傷評估方法可以比較準確地描述墩柱的破壞狀態.軸壓力對墩柱抗撞能力的有利貢獻比較有限, 且墩柱隨著軸力的增大更易發生剪切破壞; 沖頭剛度對碰撞力和墩柱動態響應的影響十分顯著.Abstract: Anti-impact design is a very important aspect to ensure the safety of reinforced concrete (RC) bridges against extreme loads, such as explosions from terrorists attacks and accidental collisions of rockfalls and vehicles. The impact behavior of the pier columns, which is the most important vertical components in the bridge structures, have attracted much attention in recent years, and experimental studies on the impact behavior of scaled pier columns have been conducted by many researchers. It has been acknowledged that the size effect has a significant influence on the dynamic response of structural elements. Therefore, in this study, the performance of the prototype reinforced concrete pier columns under lateral impact loads was investigated. Using a numerical simulation technique, three-dimensional finite element models of a prototype pier column under impact loading were established and validated through comparisons with impact tests in the literature. A new damage assessment method based on the sectional damage factor was presented to determine the damage level of reinforced concrete pier columns. The effects of impact parameters such as impact mass, impact velocity, and impact stiffness on the failure mode and damage mechanism of reinforced concrete pier columns were also identified in detail. The simulation results show that the energy dissipation of reinforced concrete pier columns under impact loading can be divided into local energy dissipation in the contact area and overall energy dissipation in the whole component. When the initial kinetic energy of the impact body remains constant, different combinations of the impact mass and velocity can lead to a significant discrepancy in the damage mechanism of reinforced concrete pier columns. The proposed damage assessment method based on sectional damage factors can be utilized to accurately describe the failure state of the reinforced concrete pier columns. In addition, the contribution of the axial load to the impact capacity of reinforced concrete pier columns is limited, and the columns are more likely to suffer shear failure with the increasing axial force. The impact stiffness has a significant effect on the impact force and the dynamic response of reinforced concrete pier columns.
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圖 1 鋼筋混凝土梁的尺寸及配筋(單位: mm)
Figure 1. Dimension and reinforcement layout of reinforced concrete beams (unit: mm)
圖 3 沖擊后鋼筋混凝土梁的損傷分布對比
Figure 3. Comparison of damage patterns of the impacted reinforced concrete beam
圖 4 碰撞力(a) 和跨中撓度(b) 試驗和模擬結果對比
Figure 4. Experimental and simulated results comparison of impact force (a) and mid-span displacement (b)
圖 5 鋼筋混凝土墩柱有限元模型(單位: mm)
Figure 5. Finite element model of reinforced concrete pier column (unit: mm)
圖 6 沖擊作用下墩柱損傷演變過程. (a) 3 ms; (b) 9 ms; (c) 30 ms; (d) 80 ms
Figure 6. Damage development of reinforced concrete pier under impact loading: (a) 3 ms; (b) 9 ms; (c) 30 ms; (d) 80 ms
圖 11 各個工況下鋼筋混凝土墩柱的損傷狀態
Figure 11. Damage states of the reinforced concrete pier columns
圖 13 沖量、耗能分別與初始動量、動能的比值
Figure 13. Ratios of the impulse to the initial momentum and the inter-nal energy to the initial kinetic energy
圖 14 碰撞力峰值與初始動能的關系
Figure 14. Relationships of peak impact force and initial kinetic energy
圖 15 墩柱各部分材料耗能與初始動能的比值
Figure 15. Ratios of the energy dissipation of material composition to the initial kinetic energy
中文字幕在线观看表 1 墩柱設計參數及動態響應
Table 1. Design parameters and dynamic response of the reinforced concrete pier columns
設計工況 沖擊質量/
t沖擊速度/
(m·s-1)初始動能/
kJ軸壓比/
%沖擊體彈簧剛度/
(MN·m-1)碰撞力峰值/
MN碰撞點最大位移/
mm體系沖量/
(kN·s)墩柱耗能/
kJ損傷因子，
ds墩柱破壞狀態 C1 10 15 1125 0 — 16.97 190 168 1068 0.903 構件失效 C2 10 15 1125 7 — 17.60 179 167 1066 0.895 重度損傷 C3 10 15 1125 14 — 18.37 189 160 1084 0.912 構件失效 C4 10 15 1125 28 — 19.27 — 127 — — 構件失效 C5 10 15 1125 7 20 6.14 54 280 241 0.814 重度損傷 C6 10 15 1125 7 200 12.21 191 163 1025 0.917 構件失效 C7 10 15 1125 7 2000 16.26 182 168 1060 0.903 構件失效 C8 5 10 250 7 — 12.49 26 61 218 0.795 重度損傷 C9 5 15 562.5 7 — 16.61 59 87 512 0.854 重度損傷 C10 5 20 1000 7 — 20.55 132 110 949 0.902 構件失效 C11 5 25 1562.5 7 — 24.73 211 135 1493 0.917 構件失效 C12 10 10 500 7 — 13.54 60 120 440 0.875 重度損傷 C13 10 20 2000 7 — 21.48 — 212 — — 構件失效 C14 20 5 250 7 — 9.35 37 130 198 0.794 重度損傷 C15 20 10 1000 7 — 14.12 173 228 929 0.885 重度損傷 C16 20 15 2250 7 — 18.21 — 272 — — 構件失效 C17 30 5 375 7 — 9.54 56 188 307 0.850 重度損傷 C18 30 10 1500 7 — 14.33 — 281 — — 構件失效 
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