33 2 2011 4 Vol. 33 No. 2 Apr. 2011 1002-8412 2011 02-0096-08 1 1 1 2 3 1. 361005 3. 361004 361005 2. 30 TU746. 3 A Study on the Strengthen Method of Masonry Structure by Steel Truss for Collapse Prevention Liao Zi-jian 1 Zhang Peng-cheng 1 Lin Shuzhi 1 2 Xiao Wei 3 1. Department of Civil Engineering Xiamen University Xiamen 361005 China 2. Xiamen Construction and Administration Bureau Xiamen 361005 China 3. Xiamen Hordor Architecture & Engineering Design Group Co. Ltd. Xiamen 361004 China Abstract In the last 30 years of the last century in China a large number of masonry structure has been built which takes up a considerable proportion of the existing dwelling house and school building. So the reconstruction and reinforcement of masonry structures is still in the present era of great significance. A new method to strengthen masonry structures by steel truss for collapse prevention including the assumptions and design principles is proposed and the design process of the method is also given. The result shows that this method can play an important role in improving safety margin of the system and it is an economical and feasible new method for strengthening the existing masonry structure. Keywords collapse prevention steel truss reinforcement of masonry structure safety margin of the system new method E-mail zpcchina@ yahoo. com. cn 1 2008 3 1978 1989 2001 4 2010-01-25 April 2011
33 2 97 2 1 Fig. 1 Calculation diagram 1 2. 1 ρ k 2 1 PKPM STS-PK 2 k 0 F 1 Δ 1 3 4 2. 3 5 1 1 2. 2 2 a b c V i Fig. 2 2 Calculation model of steel truss Vol. 33 No. 2 2011
98 2011 4 V ij K ij K ij K i V i V i 2 K ij j 1 j i f ve ζ N f v 8 K ij i K i f v GB50003-2001 ζ N 2 GB50011-2001 2. 5 1 V i V ijm V ij + m 1 m 1 k j V ij 3 V ijm i j m V ij i j γ RE m 1 f ve A V ij - 10 m 1 i j m 2 j m V 0jm V + ij m 1 m 1 γ RE k j V ij 4 γ RE 0. 75 0. 9 1. 0 V u V V 1. 3V k 6 V f ve A γ RE 7 A f ve V ijm V + ij m 1 m 1 V k ij f ve A 9 j γ RE V 0jm j m 2. 4 3 a b V V u 5 1 /1000 5mm 1 /1000 April 2011
33 2 99 1 /1000 2. 7 4 Fig. 3 3 Cracking but standing masonry structure 2. 6 4 4 Fig. 4 Flow chart of the design Vol. 33 No. 2 2011
100 2011 4 2. 8 1 B 40 2 1 3 0. 08 7. 5 B α max 0. 11 4 1 Table 1 Seismic influence coefficient reduction coefficient 30 40 50 3 0. 75 0. 88 1. 0 3. 1 4 5 6 1989 7 G eq 0. 85 n G i 12365kN GB50011-2001 7. 5 0. 08G eq 988kN 7 Ⅱ F EK α max G eq { 0. 11G eq 1360kN 7. 5 240mm 600mm 240 MU10 2 M5 3. 2 Table 2 2 GB50023-2009 7 i 1 The horizontal stiffness of the wall and the distribution factor α max 7 7. 5 F i kn V i kn 1. 3V i kn F i kn V i kn 1. 3V i kn 4 381. 2 381. 2 495. 56 524. 8 524. 8 682. 24 3 303. 4 684. 6 889. 98 417. 6 942. 4 1225. 12 2 202. 3 886. 9 1152. 97 278. 4 1220. 8 1587. 04 1 101. 1 988 1284. 4 139. 2 1360 1768 σ 0 0. 70MPa ζ N 1. 63 V 11 V 12 0. 5V 1 f ve ζ N f v 1. 63 0. 11 0. 179N / mm 2 5 1 1 2 2 3 3 V u f ve A 0. 179 240 1000 γ RE 0. 9 47. 73kN 2 7 7. 5 B 2 V 1j2 1 j V 12 1 16 V 1 110. 5kN April 2011
33 2 101 Fig. 5 5 Floor plan of the brick masonry building 3 Table 3 The horizontal stiffness of the wall and the distribution factor ρ k α 1 1 1 2 2 1 < 2. 88 < 4 0. 033E 0. 297 1 < 1. 44 < 4 0. 0073E 0. 066 1 < 3. 6 < 4 0. 0042E 0. 125 6 γ RE V m 1 V ij - u m 1 Fig. 6 Section plan of the brick masonry building 0. 0042E 0. 9 884-0. 0336E 47. 73 10 0. 0364E E Vol. 33 No. 2 2011
102 2011 4 E 1390f 1807MPa 3. 3 8 2 600mm 5 a 7 a 62. 75kN 7 b 1 8 k 0 F 3 Fig. 8 62. 75 10 Δ 1 5. 8 10818N / mm 0. 0060E θ 5. 8 3000 1 520 Fig. 7 7 Strengthening schemes 1 by steel truss 4 5 2 2500mm 5 b 8 a 125. 5kN 8 b 1 74. 1kg 2372kg k 0 F 3 125. 5 10 Δ 1 2. 0 62750N / mm 0. 0347E Strengthening schemes 2 by steel truss θ 2. 0 3000 1 1500 V 0i2 1 5 V 12 1 10 V 1 176. 8kN V 1j2 1 40 V 12 1 80 V 1 22. 1kN < V u 47. 73kN θ 2. 9 3000 1 1000 1 2 1 April 2011
33 2 103 References 1 GB50003-2001 S GB50003-2001 Code for Design of Masonry Structures S in Chinese 2 GB50011-2001 S GB50011-2001 Code for Seismic Design of Buildings S in Chinese 3 GB50023-2009 S GB50023-2009 Code for Building Seismic Appraiser S in Chinese 4 J. 2008 29 4 42 ~ 50 Ye Lie-ping Qu Zhe Lu Xin-zheng et al. Collapse prevention of building structures a lesson from the Wenchuan earthquake J. Journal of Building Structures 2008 29 4 42 ~ 50 in Chinese 5. 4 J. 2008 29 4 26 ~ 33 Wang Ya-yong. Lessons learnt from building damages in the Wenchuan earthquake three earthquake performance objectives and basic requirements for seismic design of buildings J. Journal of Building 1 /1000 Structures 2008 29 4 26 ~ 33 in Chinese 1 /1000 6 J. 2008 38 6 11 ~ 15 Ye Lie-ping Cheng Guang-yu Lu Xin-zheng et al. Introduction of robustness for seismic structures J. Building Structure 2008 38 6 11 ~ 15 in Chinese 7. J. 2009 9 5 631 ~ 638 Liu Xiao-feng Cai Xian-hui Cheng Geng-dong. Earthquake damage of masonry buildings and anchoragetie strengthening method for rural houses J. Journal of Dalian University of Technology 2009 9 5 631 ~ 638 in Chinese 8. J 2008 10 5 38 ~ 43 in Chinese Liu Hai-qing Ni Zhen-guo Ou Jin-ping. Simulation analysis of the collapse response of masonry structures subjected to strong ground motion J. Journal of Earthquake Engineering and Engineering Vibration 2008 10 5 38 ~ 43 in Chinese 9 JGJ 116-98 S. JGJ 116-98 Technical Specification for Seismic Strengthenng of Building S in Chinese 1984 ~ Vol. 33 No. 2 2011