Tests on impact effect of partial fracture at steel frame connections

Abstract

Impact effect of sudden fracture at steel frame connections under severe earthquake or other extreme loads is presented in this paper. The relation of impulse caused by structural fracture to the release of inner force at the cracked location, the magnitude of the response to impact on the basis of one degree of freedom model, and the ratio of the peak value of response to natural period of the system are investigated. Two types of fracture tests were designed and carried out both on uniaxial steel bar tensioned and moment resistant steel frame model. It is proven that the response during the fracture process can be measured quite well using high-frequency data processing system. It is also revealed that the instant fracture of structural connection is characterized by progressive and partial fracture. Numerical evaluation of the impact effect of connection fracture is carried out.

References

1. Building ResearchInstitute Ministry of Construction. . A Survey Report for BuildingDamages Due to The 1995 Hyogo-Ken Nanbu Earthquake. Tokyo: Building Research InstituteMinistry of Construction, 1996
2. Mahin S A . Lessons from damage to steel buildings during the Northridge earthquake. Engineering Structures, 1998, 20: 261–270. doi:10.1016/S0141-0296(97)00032-1
3. Roeder C W . Experimental results for seismic resistant steel moment frame connections. Journal of Structural Engineering, 1996, 122(6): 581–588. doi:10.1061/(ASCE)0733-9445(1996)122:6(581)
4. Tide R H R . Stability of weld metal subjected to cyclic static and seismic loading. Engineering Structures, 1998, 20: 562–569. doi:10.1016/S0141-0296(97)00094-1
5. Popov E P, Yang T S, Chang S P . Design of steel MRF connections before and after 1994Northridge earthquake. Engineering Structures, 1998, 20: 1030–1038. doi:10.1016/S0141-0296(97)00200-9
6. Chi B, Uang C M . Cyclic response and designrecommendations of reduced beam section moment connections with deepcolumns. Journal of Structural Engineering, 2002, 128 (4): 464–473. doi:10.1061/(ASCE)0733-9445(2002)128:4(464)
7. Espiga F . Ductilityassessment methods and safety evaluation based on rotation capacityapproach. Journal of Constructional SteelResearch, 1998, 46(1–3): 446–447. doi:10.1016/S0143-974X(98)00143-6
8. Bertero R D, Bertero V V . Redundancy in earthquake-resistantdesign. Journal of Structural Engineering, 1999, 125(1): 81–88. doi:10.1061/(ASCE)0733-9445(1999)125:1(81)
9. Husain M, Tsopelas P . Measures of structural redundancyin reinforced concrete buildings. I: redundancy indices.Journal of Structural Engineering, 2004, 130(11): 1651–1658. doi:10.1061/(ASCE)0733-9445(2004)130:11(1651)
10. Memari A M, Harris H G, Hamid Ahmad A . Ductility evaluation for typical existing R/C bridgecolumns in the eastern USA. EngineeringStructures, 2005, 27: 203–212. doi:10.1016/j.engstruct.2004.09.011
11. Chen Yiyi, Jiang Zhaolong, Shen Zhuyan . Research comment on steel structure cracking and theconcept of damage control design. Journalof Tongji University (Natural Science), 1999, 27(5): 587–591 (in Chinese)
12. Liu Yongming, Chen Yiyi, Chen Yangji . Hysterical model of steel frame connection consideringpartial fracture. Journal of Tongji University(Natural Science), 2003, 31(5): 525–529 (in Chinese)
13. Clough R W, Penzien J . Dynamics of Structures. Translatedby Wang Guangyuan. Beijing: Science Press, 1981 (in Chinese)