【正文】 警示牌，告誡人們要愛護(hù)橋梁，不要或盡量減少在橋上跑動和跳躍，為自己也為他人創(chuàng)造一個和諧的過橋環(huán)境。參 考 文 獻(xiàn)[1] 姚玲森主編．橋梁工程．北京：人民交通出版社，2003年9月. [2] 高品賢. 振動、沖擊及噪聲測試技術(shù)[M]. 成都：西南交通大學(xué)出版社,2010. [3] 殷祥超. 振動理論與測試技術(shù)[M]. 徐州：中國礦業(yè)大學(xué)出版社,2010. [4] 彭俊生, 羅永坤, 彭地. 結(jié)構(gòu)動力學(xué)、抗震計(jì)算與SAP :西南交通大學(xué)出版社,2007. [5] 陳政清，:人民交通出版社，2009.[6] 羅英：《中國石橋》，人民交通出版社，北京，1959.[7] 茅以升主編：《中國古橋技術(shù)史》，北京出版社，北京，1986.[8] －Smith，The World’s Great Brides，.，Harper amp。 Row，New York，1965.[9] S. Zivanovic, A. Pavic, P. Reynolds. Vibration serviceability of footbridges under humaninduced excitation: a literature review[J]．Journal of Sound and Vibration. 2005(279): 174. [10] Adrienne E. Hunt, Richard M. smith, Marg Torode. Intersegment foot motion and ground reaction forces over the stance phase of walking[J]．Clinical Biomechanics. 2001(16): 592600. [11] . Law. Dynamic load from pedestrian footsteps[J]．Advances in Steel Structures. 2002, 2. [12] Shunichi Nakamura, Toshitsugu Kawasaki, Hiroshi Katsuura. Experimental studies on lateral forces induced by pedestrians[J]．Journal of Constructional Steel Research. 2008(64): 247252. [13] S. Yao, . Wrighta, A. Pavic. Experimental study of humaninduced dynamic forces due to jumping on a perceptibly moving structure[J]．Journal of Sound and Vibration. 2006(296): 150165. [14] Matt T, thinking and practice for program [M].beijing：China Water Conservancy and Water electricity .附 錄附錄A 外文原文DYNAMIC LOAD FROM PEDESTRIAN FOOTSTEPS. LawDepartment of Civil and Structural Engineering, Hong Kong Polytechnic UniversityHunghom, Kowloon, Hong Kong, ChinaABSTRACTThe performance of pedestrian footbridge under environmental and pedestrian excitation has received much attention lately with the problem of resonating vibration of the Millennium Bridge in London. The dead weight of the bridge is small with increased improvement in the design method and the use of lightweight and high strength materials. Damping mechanism is seldom provided for this type of structure. This gives rise to unacceptable vibration from human or environmental excitations and causes alarm. This paper studies the vertical dynamic load generated by pedestrian footsteps on a simply supported steel bridge deck. The forces are identified using an existing algorithm on moving force identification developed by the author (Law and Fang, 2001). The identified footstep force is then generalized using a time series and the coefficients of which are obtained from collected samples of footstep forces. Further analysis on the samples collected is in process, and results would be useful for dynamic design of the performances of the pedestrian footbridge.KEYWORDSForce identification；pedestrian；footstep；dynamic programming；velocity；strain；steel beam.INTRODUCTIONThe recent resonating vibration of the Millennium Bridge in London (Dallard et al., 2001) raises alarm on the lack of knowledge on the dynamic behavior of the structure when groups of pedestrian move across the bridge deck. The force generated by different group size of people varies and it could excite a lightweight bridge deck with little damping capacity into resonance. This paper gives the dynamic loading from footstep of pedestrian as measured indirectly from the dynamic responses of the structure as an alternative approach of measurement. The interaction between the pedestrian and the bridge deck is taken into account in the identification of the footstep forces. Existing algorithm on moving force identification was used in the study (Law and Fang, 2001). The loading when pared with the pseudodynamic loading obtained from load cells indicates the presence of high frequency ponents and a larger magnitude due to the slow response of the load cell to dynamic load. The identified footstep force is generalized using a time series, and the coefficients of which are obtained from samples of the identified footstep forces. The results indicate the existence of higher frequency ponents of the impulsive footsteps which cannot be obtained from the pseudodynamic test by Ebrahimpour et al. (1996). These would be useful for dynamic design of footbridge under groups of moving pedestrians.MOVING FORCES IDENTIFICATION ALGORITHMThe method to identify the moving footstep loads is adapted from previous work by the author (Law and Fang, 2001). The forces in the statespace formulation of the dynamic system are identified in the time domain using the dynamic programming technique and information from several distributed sensor measurements. Responses of the structure are reconstructed using the identified forces for parison with the measured responses as a means of assessment the accuracy of identification. The problem formulation is briefly described below, and details on the solution of the equations are referred to Law and Fang (2001).AssumptionsThe following assumptions are made on the dynamic system model: (a) The changes in the system characteristics, . the stiffness, damping and mass matrices under the passage of the force are negligible, and (b) EulerBemoulli beam model is used with the shear effect neglected.Nodal Forces from an Applied ForceWhen a force time history f1 is applied on a twodimensional finite beam element of length l between the ith and (i+l)th nodes at a point distant x from the left end, the nodal forces at each end of the beam element can be found and grouped into the global force vector as P = Y(x)f1 (1)Where P is the nodal force vector and Y(x) is the vector on the location of the applied force. For the case of multiforces acting on the beam element, the global force vector arising from the ith. force is represented by Pi = Y(xi).fi (2)State Space ModelThe finite element representation of a nDOFs dynamic system is given by: Mu+Cu + Ku= P (3)