Measurement of ambient vibration of a twin-tower building with enlarged base and model modification

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1 CHINA CIVIL ENGINEERING JOURNAL Vol. 42 No. 2 Feb PKPM SATWE TU X A Measurement of ambient vibration of a twin-tower building with enlarged base and model modification Yi Weijian 1 Zhou Yun 1 Qin Liaohui 2 ( 1.Hunan University Changsha China; 2. Changsha Academy of Urban Planning and Design Changsha China) Abstract: A modal experiment of a full-scale 27 story frame-shear wall high-rise building structure was conducted using ambient vibration measurements. The building consists of two towers connected by air corridors and an enlarged base. The natural frequencies translation and torsion mode shapes were measured and the analytical natural frequencies and mode shapes were obtained by using the SATWE module of the software PKPM. In comparison with the empirical formulas for calculation of the fundamental frequency of tall buildings in different countries it is found that the measured fundamental frequency of the structure is higher than the calculated and empirically-evaluated fundamental frequency indicating either the stiffness of the structure larger than that of the analytical model or the mass of the structure smaller than that of the analytical model. By considering the stiffness effect of the basement of the structure and the actual load on the floors a primary model update was conducted. Then the infill-wall was modeled as an equivalent inclined brace and its width was optimized in the final model updating. After model updating the calculated natural frequencies agree well with the measured data illustrating that the method can be used in model updating of high-rise building structures. Keywords: twin-tower structure with enlarged base; tall building; random vibration measurement; experimental modal analysis; infill wall model; dynamic model updating hunuyi2006@gmail.com :

66 2009 1.1 1 ( Brownjohn [1-2] - ) 27577.28 m 2 1217.68 m 2 Li [3] 325 m 86.

2 ( Brownjohn [1-2] - ) m m 2 Li [3] 325 m m C35~C45 Wu [4] 2800 kn/m m Chassiakos [5] ( 2) Chaker [6] Thiruvengadam [7] [8] 1 2 Fig. 1 Panorama of the Fig. 2 Front view of the Ruihua Building Ruihua Building Amanat [9] 1.2 ( ) 1 - S xx (ω) a (1): H(ω) 2 =S yy (ω)/s xx (ω)=s yy (ω)/a (1) SATWE

3 DASP INV ~100 Hz ; 1 ; INV303 1 Fig. 4 3~5 : (1) 3 X Y 3 A-A A-B X A-C Y 64 ( 512 ) 14 E~F X F-G Y 64 4 (2) 24 (25 ) D D X Y 64 6~ Hz X X Y Hz Hz Hz 5 Fig Placement of measurement point on the 14th story Placement of measurement point on the standard story 6 A-A X Fig. 6 Calibration of the transducer on A-A point in X direction Fig. 3 3 Placement of measurement point on the top story Fig. 7 7 A-B X Cross power spectrum on A-B point in X direction

68 2009 2 8 24 ~20 D Y Fig. 8 Cross power spectrum on D point on 24~20 story in Y direction 9 14 F-G Y Fig.

4 ~20 D Y Fig. 8 Cross power spectrum on D point on 24~20 story in Y direction 9 14 F-G Y Fig. 9 Cross power spectrum on F-G point on 14 story in Y direction 2.1 PKPM 11 PKPM SATWE (JGJ3 2002) - - T= (0.08~0.1) N 2.16 s~2.7 s 0.46 Hz~0.37 Hz [10] 1977 Fig Transverse vibration shapes by measurement

42 2 69 11 SATWE Fig. 11 The SATWE model 1971 San Fernando 6.6 8 70 1.1~2.0 1.0~ 1.4 2 [11] 1.5 0.684 0.402 1.

5 SATWE Fig. 11 The SATWE model 1971 San Fernando ~ ~ [11] ( ) 1978 Table 1 1 Value from calculating modal analysis f 1Y f 2X f 3T f 4Y f 5T f 6X f 7Y f 8T f 9X f 10Y f 11Y f 12Y X x Y y T (Hz) Table 2 2 Comparison of the natural frequencies between calculation and measurement T N 0.05H/ 姨 B H 2 3 姨 B 0.065N T 1s f 1Hz ; 4 ; ±0.000 ± ; 1.70 ; 1.51 [11] %

70 2009 3 : Table 3 Comparison of cases in initial model updating [12-13] Case 1 2 Case 2 Case 1 12 Case 3 Case 2 [12] 3.2 3 : t E h t 1/2 [12] 1.

6 : Table 3 Comparison of cases in initial model updating [12-13] Case 1 2 Case 2 Case 1 12 Case 3 Case 2 [12] : t E h t 1/2 [12] Table 4 4 Comparison of the numerical frequencies by initial model updating Hz f 1X f 2Y f 3T f 4X f 5Y f 6T f 7X f 8T f 9Y f 10X f 11T f 12T Case Case Case a Table 5 b 12 Fig. 12 Simplified inclined brace 5 Comparison of the cases by detailed model updating c Case 4 Case 5 Case 6 Case 7 Case 8 Case mm 600 mm 250 mm 300 mm Case mm 400 mm 250 mm 200 mm Case mm 300 mm 250 mm 150 mm Case mm 250 mm 250 mm 125 mm Case mm 200 mm 250 mm 100 mm Table 6 6 Comparison of the numerical frequencies by detailed model updating Hz f 1X f 2Y f 3T f 4X f 5Y f 6T f 7X f 8T f 9Y f 10X f 11T f 12T Case Case Case Case Case

42 2 71 250 mm Case 6 13 5 6 x 250 mm y 1.04 4 13 Case 6 Fig. 13 Mode shapes of Case 6 (3) - 0.452 Hz 1.51 [11] PKPM SATWE h=250 mm : 1.04 (1) 1Brownjohn J M W Pan T C Deng X Y. Correlating 0.

7 mm Case x 250 mm y Case 6 Fig. 13 Mode shapes of Case 6 (3) Hz 1.51 [11] PKPM SATWE h=250 mm : 1.04 (1) 1Brownjohn J M W Pan T C Deng X Y. Correlating Hz dynamic characteristics from field measurements and SATWE Hz numerical analysis of a high-rise building J Earthquake Engineering and Structural Dynamics (2) Brownjohn J M W. Ambient vibration studies for system identification of tall buildings J. Earthquake Engin-

8 eering and Structural Dynamics Li Q S Wu J R. Correlation of dynamic characteristics of a super-tall building from full-scale measurements and numerical analysis with various finite element models J. Earthquake Engineering and Structural Dynamics Wu J R Li Q S. Finite element model updating for a high-rise structure based on ambient vibration measurementsj. Engineering Structures : Chassiakos A G Masri S F Nayeri R D et al. Use of vibration monitoring data to track structural changes in a retrofitted building J. Structural Control and Health Monitoring : Chaker A A Cherifati A. Influence of masonry infill panels on the vibration and stiffness characteristics of R/ C frame buildings J. Earthquake Engineering and Structural Dynamics : Thiruvengadam V. On the natural frequencies of infilled frames J. Earthquake Engineering and Structural Dynamic : J : Gao Xiaowang Pu Qingshun. The value of period reduction coefficient and the elastic storey displacement correction coefficient in multistorey frame structure J. Building Structure : in Chinese 9Amanat K M Hoque E. A rationale for determining the natural period of RC building frames having infill J. Engineering Structures : M. : M. : D. : 2004 Li Changqing. Dynamic model modification of infilled frame D. Changsha: Hunan University 2004in Chinese 13. D. : 2004 Qin Peng. Dynamic experiment and analytical study of infilled frames D.Changsha: Hunan University 2004in Chinese

2nd International Conference on Electronic & Mechanical Engineering and Information Technology (EMEIT-2012)

2nd International Conference on Electronic & Mechanical Engineering and Information Technology (EMEIT-2012) Study on simplified calculation method for the vibration characters of frame-shear wall structures Huang Minshui, a, Tu Yueya, b, Zhang Shishun,c School of Environment and Civil Engineering, Wuhan Institute