近场爆炸时预应力混凝土梁体抗爆分析
|
摘要
为了研究预应力混凝土梁在爆炸荷载下的动力响应、破坏模式以及不同预应力条件对结构抗爆性能的影响,结合流固耦合理论,采用LS-DYNA有限元软件建立预应力混凝土梁实体模型,开展不同炸药条件,不同预应力度和不同爆心位置条件下的预应力混凝土梁体结构抗爆分析。结果表明:①混凝土梁体的破坏模式随炸药当量的增加而变化,小当量炸药条件下,混凝土梁体表现为传统的受弯构件,随着炸药当量增加,梁体迎爆面出现压溃破坏,继续增大炸药当量,梁体迎爆面压溃引起的混凝土剥离面积和深度增大,导致截面抗压能力减弱,梁体由适筋设计的塑性破坏转为脆断;②当中等炸药当量在梁上方爆炸时,按抗弯要求设置的预应力效应能提高抗爆能力10%左右,反之,当其在梁体下方爆炸时,由于预应力效应的不利叠加会导致梁体抗爆能力明显下降;③对于同等炸药当量条件下沿梁跨径方向不同位置的爆炸,跨中爆炸时梁体受力最为不利,爆点位于支座处梁体上方时,由于支座的边界约束作用,梁体动力响应和损伤较小;④同等炸药当量条件下,爆心相对梁体上下位置的改变将引起预应力混凝土梁体破坏模式的改变;⑤灌浆对预应力混凝土梁体的抗爆性能影响不明显,有黏结预应力和无黏结预应力混凝土梁体在不同爆炸荷载作用下表现出相似的动力特性和力筋应力增量变化规律。
To study the dynamic responses and failure modes of prestressed concrete beams under blast loads, finite element models for the concrete beams based on LS-DYNA were established using the fluid-solid coupling method to perform dynamic analyses of constructions under different TNT weights, detonation locations, and stress conditions. The results show that: ① The damage mode changes with increase in TNT equivalent weights. Under the condition of low TNT weight, the concrete beam behaves as a traditional bent member. As the TNT weights increases, the beam begins to crack. When the TNT equivalent weight is large enough, owing to the continuous peeling of the concrete compression area, the damage mode changes from plastic failure to brittle fracture. ② When medium-blast loading occurs above the beam, prestressed concrete beams can improve anti-blast resistance by approximately 10%; on the contrary, when exploding beneath the prestressed concrete beams, the prestressing has a great negative influence on the anti-blast resistances. ③ Under the same TNT weights, the most serious damages occur when the explosions are in the mid-span region compared to explosions in other positions along the beam. When the explosions are located above the support, the dynamic response and damage of beams are small due to the boundary constraint of the support. ④ Under the same TNT weights, different detonation locations may change the damage modes of the prestressed concrete beams. ⑤ Grout has no obvious influence on the anti-blast resistances of the prestressed concrete beams, and they exhibited similar dynamic characteristics and change rules of stress force under different blast loads.
To study the dynamic responses and failure modes of prestressed concrete beams under blast loads, finite element models for the concrete beams based on LS-DYNA were established using the fluid-solid coupling method to perform dynamic analyses of constructions under different TNT weights, detonation locations, and stress conditions. The results show that: ① The damage mode changes with increase in TNT equivalent weights. Under the condition of low TNT weight, the concrete beam behaves as a traditional bent member. As the TNT weights increases, the beam begins to crack. When the TNT equivalent weight is large enough, owing to the continuous peeling of the concrete compression area, the damage mode changes from plastic failure to brittle fracture. ② When medium-blast loading occurs above the beam, prestressed concrete beams can improve anti-blast resistance by approximately 10%; on the contrary, when exploding beneath the prestressed concrete beams, the prestressing has a great negative influence on the anti-blast resistances. ③ Under the same TNT weights, the most serious damages occur when the explosions are in the mid-span region compared to explosions in other positions along the beam. When the explosions are located above the support, the dynamic response and damage of beams are small due to the boundary constraint of the support. ④ Under the same TNT weights, different detonation locations may change the damage modes of the prestressed concrete beams. ⑤ Grout has no obvious influence on the anti-blast resistances of the prestressed concrete beams, and they exhibited similar dynamic characteristics and change rules of stress force under different blast loads.
引文
[1] 胡志坚,胡钊芳.桥梁结构爆炸荷载特性研究[C]//中国土木工程学会桥梁结构分会.第十九届全国桥梁学术会议论文集.北京:人民交通出版社,2010:771-776. HU Zhi-jian, HU Zhao-fang. Study of Blast Loading Characteristics for Bridge Structures [C]// Branch of Bridge and Structural Engineering of Civil Engineering Society of China. Proceedings of the 19th National Bridge Symposium. Beijing: China Communications Press, 2010: 771-776.
[2] 胡志坚,唐杏红,方建桥.近场爆炸时混凝土桥梁压力场与响应分析[J].中国公路学报,2014,29(5):141-147,157. HU Zhi-jian, TANG Xing-hong, FANG Jian-qiao. Analysis of Pressure Field and Response for Concrete Bridges Under Close Blast Loading [J]. China Journal of Highway and Transport, 2014, 29 (5): 141-147, 157.
[3] 崔满.爆炸荷载作用下钢筋混凝土梁的试验研究[D].上海:同济大学,2007. CUI Man.Experimental Research of Reinforced Concrete Beam Under the Explosive Load [D]. Shanghai: Tongji University, 2007.
[4] ZHANG D,YAO S J,LU F, et al. Experimental Study on Scaling of RC Beams Under Close-in Blast Loading [J]. Engineering Failure Analysis, 2013, 33 (5): 497-504.
[5] 高超,宗周红,伍俊.爆炸荷载下钢筋混凝土框架结构倒塌破坏试验研究[J].土木工程学报,2013,46(7):9-20. GAO Chao, ZONG Zhou-hong, WU Jun. Experimental Study on Progressive Collapse Failure of RC Frame Structures Under Blast Loading [J]. China Civil Engineering Journal, 2013, 46 (7): 9-20.
[6] 宗周红,唐彪,高超,等.钢筋混凝土墩柱抗爆性能试验[J].中国公路学报,2017,30(9):51-60. ZONG Zhou-hong, TANG Biao, GAO Chao, et al.Experiment on Blast-resistance Performance of Reinforced Concrete Piers [J]. China Journal of Highway and Transport, 2017, 30 (9): 51-60.
[7] COFER W F,MATTHEWS D S,MCLEAN D I. Effects of Blast Loading on Prestressed Girder Bridges [J]. Shock & Vibration, 2015, 19 (1): 1-18.
[8] YUAN S,HAO H,ZONG Z, et al. A Study of RC Bridge Columns Under Contact Explosion [J]. International Journal of Impact Engineering, 2017, 109: 378-390.
[9] HASHEMI S K, BRADFORD M A, VALIPOUR H R. Dynamic Response and Performance of Cable-stayed Bridges Under Blast Load: Effects of Pylon Geometry [J]. Engineering Structures, 2017, 137: 50-66.
[10] ISHIKAWA N, ENRIN H, KATSUKI S, et al. Dynamic Behavior of Prestressed Concrete Beams Under Rapid Speed Loading [J]. WIT Transactions on the Built Environment, 1998, 10: 717-726.
[11] ISHIKAWA N, KATSUKI S, TAKEMOTO K. Dynamic Analysis of Prestressed Concrete Beams Under Impact and High Speed Loadings [J]. WIT Transactions on the Built Environment, 2000, 35: 247-256.
[12] ISHIKAWA N, KATSUKI S, TAKEMOTO K. Incremental Impact Test and Simulation of Prestressed Concrete Beam [J]. WIT Transactions on the Built Environment, 2002, 63: 489-498.
[13] STOCHINO F. RC Beams Under Blast Load: Reliability and Sensitivity Analysis [J]. Engineering Failure Analysis, 2016, 66: 544-565.
[14] SHIRAVAND M R,PARVANEHRO P,SHIRAVAND M R, et al. Numerical Study on Damage Mechanism of Post-tensioned Concrete Box Bridges Under Close-in Deck Explosion [J]. Engineering Failure Analysis, 2017, 81: 103-116.
[15] CHEN W, HAO H, CHEN S. Numerical Analysis of Prestressed Reinforced Concrete Beam Subjected to Blast Loading [J]. Materials & Design, 2015, 65: 662-674.
[16] 李砚召,王肖钧,张新乐,等.预应力混凝土结构抗爆性能试验研究[J].实验力学,2005,20(2):179-185. LI Yan-zhao,WANG Xiao-jun, ZHANG Xin-le, et al. Test Study on Anti-detonation Quality of Presterssed Concrete Structure [J]. Journal of Experimental Mechanics, 2005, 20 (2): 179-185.
[17] 夏小虎.预应力钢筋混凝土梁在爆轰条件下的动力行为研究[D].武汉:武汉理工大学,2012. XIA Xiao-Hu. The Dynamic Behavior Research of Prestressed Concrete Beam Under the Conditions of Detonation [D]. Wuhan: Wuhan University of Technology, 2012.
[18] 胡志坚,王云阳,胡钊芳,等.预应力混凝土梁开裂后抗弯刚度试验研究[J].桥梁建设,2012,42(5):37-43. HU Zhi-jian, WANG Yun-yang, HU Zhao-fang, et al. Test Study of Flexural Stiffness of Prestressed Concrete Beams with Cracks [J]. Bridge Construction, 2012, 42 (5): 37-43.
[19] JOHNSON G R,HOLMQUIST T J. An Improved Computational Constitutive Model for Brittle Materials [J]. 1994, 309 (1): 981-984.
[20] 亨利奇.爆炸动力学及其应用[M].北京:科学出版社,1987. HENRYCH J. The Dynamics of Explosion and Its Use [M]. Beijing: Science Press, 1987.
[21] 王飞,朱立新,顾文彬,等.基于ALE算法的空气冲击波绕流数值模拟研究[J].工程爆破,2002,8(2):13-16. WANG Fei , ZHU Li-xin , GU Wen-bin, et al.Numerical Simulation of Shock Wave Around-flow on Basis of ALE Algorithms [J]. Engineering Blasting, 2002, 8 (2): 13-16.
[22] 方秦,吴平安.爆炸荷载作用下影响RC梁破坏形态的主要因素分析[J].计算力学学报,2003,20(1):39-42. FANG Qin, WU Ping-an. Main Factors Affecting Failure Modes of Blast Loaded RC Beams [J]. Chinese Journal of Computational Mechanics, 2003, 20 (1): 39-42.
[23] 方秦,柳锦春.爆炸荷载作用下钢筋混凝土梁破坏形态有限元分析[J].工程力学,2001,18(2):1-8. FANG Qin, LIU Jin-chun. Finite Element Analysis of Failure Modes of Blast-loaded R/C Beams [J]. Engineering Mechanics, 2001, 18 (2): 1-8.
[24] 柳锦春,方秦,龚自明,等.爆炸荷载作用下钢筋混凝土梁的动力响应及破坏形态分析[J].爆炸与冲击,2003,23(1):25-30. LIU Jin-chun, FANG Qin, GONG Zi-ming, et al. Analysis of Dynamic Responses and Failure Modes of R/C Beams Under Blast Loading [J]. Explosion and Shock Waves, 2003, 23 (1): 25-30.
[2] 胡志坚,唐杏红,方建桥.近场爆炸时混凝土桥梁压力场与响应分析[J].中国公路学报,2014,29(5):141-147,157. HU Zhi-jian, TANG Xing-hong, FANG Jian-qiao. Analysis of Pressure Field and Response for Concrete Bridges Under Close Blast Loading [J]. China Journal of Highway and Transport, 2014, 29 (5): 141-147, 157.
[3] 崔满.爆炸荷载作用下钢筋混凝土梁的试验研究[D].上海:同济大学,2007. CUI Man.Experimental Research of Reinforced Concrete Beam Under the Explosive Load [D]. Shanghai: Tongji University, 2007.
[4] ZHANG D,YAO S J,LU F, et al. Experimental Study on Scaling of RC Beams Under Close-in Blast Loading [J]. Engineering Failure Analysis, 2013, 33 (5): 497-504.
[5] 高超,宗周红,伍俊.爆炸荷载下钢筋混凝土框架结构倒塌破坏试验研究[J].土木工程学报,2013,46(7):9-20. GAO Chao, ZONG Zhou-hong, WU Jun. Experimental Study on Progressive Collapse Failure of RC Frame Structures Under Blast Loading [J]. China Civil Engineering Journal, 2013, 46 (7): 9-20.
[6] 宗周红,唐彪,高超,等.钢筋混凝土墩柱抗爆性能试验[J].中国公路学报,2017,30(9):51-60. ZONG Zhou-hong, TANG Biao, GAO Chao, et al.Experiment on Blast-resistance Performance of Reinforced Concrete Piers [J]. China Journal of Highway and Transport, 2017, 30 (9): 51-60.
[7] COFER W F,MATTHEWS D S,MCLEAN D I. Effects of Blast Loading on Prestressed Girder Bridges [J]. Shock & Vibration, 2015, 19 (1): 1-18.
[8] YUAN S,HAO H,ZONG Z, et al. A Study of RC Bridge Columns Under Contact Explosion [J]. International Journal of Impact Engineering, 2017, 109: 378-390.
[9] HASHEMI S K, BRADFORD M A, VALIPOUR H R. Dynamic Response and Performance of Cable-stayed Bridges Under Blast Load: Effects of Pylon Geometry [J]. Engineering Structures, 2017, 137: 50-66.
[10] ISHIKAWA N, ENRIN H, KATSUKI S, et al. Dynamic Behavior of Prestressed Concrete Beams Under Rapid Speed Loading [J]. WIT Transactions on the Built Environment, 1998, 10: 717-726.
[11] ISHIKAWA N, KATSUKI S, TAKEMOTO K. Dynamic Analysis of Prestressed Concrete Beams Under Impact and High Speed Loadings [J]. WIT Transactions on the Built Environment, 2000, 35: 247-256.
[12] ISHIKAWA N, KATSUKI S, TAKEMOTO K. Incremental Impact Test and Simulation of Prestressed Concrete Beam [J]. WIT Transactions on the Built Environment, 2002, 63: 489-498.
[13] STOCHINO F. RC Beams Under Blast Load: Reliability and Sensitivity Analysis [J]. Engineering Failure Analysis, 2016, 66: 544-565.
[14] SHIRAVAND M R,PARVANEHRO P,SHIRAVAND M R, et al. Numerical Study on Damage Mechanism of Post-tensioned Concrete Box Bridges Under Close-in Deck Explosion [J]. Engineering Failure Analysis, 2017, 81: 103-116.
[15] CHEN W, HAO H, CHEN S. Numerical Analysis of Prestressed Reinforced Concrete Beam Subjected to Blast Loading [J]. Materials & Design, 2015, 65: 662-674.
[16] 李砚召,王肖钧,张新乐,等.预应力混凝土结构抗爆性能试验研究[J].实验力学,2005,20(2):179-185. LI Yan-zhao,WANG Xiao-jun, ZHANG Xin-le, et al. Test Study on Anti-detonation Quality of Presterssed Concrete Structure [J]. Journal of Experimental Mechanics, 2005, 20 (2): 179-185.
[17] 夏小虎.预应力钢筋混凝土梁在爆轰条件下的动力行为研究[D].武汉:武汉理工大学,2012. XIA Xiao-Hu. The Dynamic Behavior Research of Prestressed Concrete Beam Under the Conditions of Detonation [D]. Wuhan: Wuhan University of Technology, 2012.
[18] 胡志坚,王云阳,胡钊芳,等.预应力混凝土梁开裂后抗弯刚度试验研究[J].桥梁建设,2012,42(5):37-43. HU Zhi-jian, WANG Yun-yang, HU Zhao-fang, et al. Test Study of Flexural Stiffness of Prestressed Concrete Beams with Cracks [J]. Bridge Construction, 2012, 42 (5): 37-43.
[19] JOHNSON G R,HOLMQUIST T J. An Improved Computational Constitutive Model for Brittle Materials [J]. 1994, 309 (1): 981-984.
[20] 亨利奇.爆炸动力学及其应用[M].北京:科学出版社,1987. HENRYCH J. The Dynamics of Explosion and Its Use [M]. Beijing: Science Press, 1987.
[21] 王飞,朱立新,顾文彬,等.基于ALE算法的空气冲击波绕流数值模拟研究[J].工程爆破,2002,8(2):13-16. WANG Fei , ZHU Li-xin , GU Wen-bin, et al.Numerical Simulation of Shock Wave Around-flow on Basis of ALE Algorithms [J]. Engineering Blasting, 2002, 8 (2): 13-16.
[22] 方秦,吴平安.爆炸荷载作用下影响RC梁破坏形态的主要因素分析[J].计算力学学报,2003,20(1):39-42. FANG Qin, WU Ping-an. Main Factors Affecting Failure Modes of Blast Loaded RC Beams [J]. Chinese Journal of Computational Mechanics, 2003, 20 (1): 39-42.
[23] 方秦,柳锦春.爆炸荷载作用下钢筋混凝土梁破坏形态有限元分析[J].工程力学,2001,18(2):1-8. FANG Qin, LIU Jin-chun. Finite Element Analysis of Failure Modes of Blast-loaded R/C Beams [J]. Engineering Mechanics, 2001, 18 (2): 1-8.
[24] 柳锦春,方秦,龚自明,等.爆炸荷载作用下钢筋混凝土梁的动力响应及破坏形态分析[J].爆炸与冲击,2003,23(1):25-30. LIU Jin-chun, FANG Qin, GONG Zi-ming, et al. Analysis of Dynamic Responses and Failure Modes of R/C Beams Under Blast Loading [J]. Explosion and Shock Waves, 2003, 23 (1): 25-30.