Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations--Ⅱ:Experiment

The possibility of using a multi-stage pendulum mass damper(MSPMD) to control wind-induced vibration of a single column tower of a cable-stayed bridge during construction was studied theoretically in part Ⅰ of this work.In this paper,the performance of the MSPMD for reducing bridge tower vibration is studied experimentally.A MSPMD model and a tower model of the bridge with geometry scaling of 1:100 were designed and manufactured.Calibration of the MSPMD model with different wire lengths is conducted to verify the analytical model of the damper.A series of tests for the uncontrolled freestanding tower,tower with cables,and tower with MSPMD model are then performed under harmonic and white noise excitations.The experimental results show that the responses of the tower model significantly decrease with the installation of the MSPMD model,which demonstrates the effectiveness of the MSPMD to mitigate the vibration of the bridge tower.     

Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations -- II： Experiment

The possibility of using a multi-stage pendulum mass damper(MSPMD) to control wind-induced vibration of a single column tower of a cable-stayed bridge during construction was studied theoretically in part Ⅰ of this work.In this paper,the performance of the MSPMD for reducing bridge tower vibration is studied experimentally.A MSPMD model and a tower model of the bridge with geometry scaling of 1100 were designed and manufactured.Calibration of the MSPMD model with different wire lengths is conducted to verify the analytical model of the damper.A series of tests for the uncontrolled freestanding tower,tower with cables,and tower with MSPMD model are then performed under harmonic and white noise excitations.The experimental results show that the responses of the tower model significantly decrease with the installation of the MSPMD model,which demonstrates the effectiveness of the MSPMD to mitigate the vibration of the bridge tower.     

Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations——Ⅰ: Theory

In this paper, wind-induced vibration control of a single column tower of a cable-stayed bridge with a multistage pendulum mass damper (MSPMD) is investigated. Special attention is given to overcoming space limitations for installing the control device in the tower and the effect of varying natural frequency of the towers during construction. First,the finite element model of the bridge during its construction and the basic equation of motion of the MSPMD are introduced.The equation of motion of the bridge with the MSPMD under along-wind excitation is then established. Finally, a numerical simulation and parametric study are conducted to assess the effectiveness of the control system for reducing the wind-induced vibration of the bridge towers during construction. The numerical simulation results show that the MSPMD is practical and effective for reducing the along-wind response of the single column tower, can be installed in a small area of the tower, and complies with the time-variant characteristics of the bridge during its entire construction stage.     

Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations --Ⅰ： Theory

In this paper, wind-induced vibration control of a single column tower of a cable-stayed bridge with a multi- stage pendulum mass damper （MSPMD） is investigated. Special attention is given to overcoming space limitations for installing the control device in the tower and the effect of varying natural frequency of the towers during construction. First, the finite element model of the bridge during its construction and the basic equation of motion of the MSPMD are introduced. The equation of motion of the bridge with the MSPMD under along-wind excitation is then established. Finally, a numerical simulation and parametric study are conducted to assess the effectiveness of the control system for reducing the wind-induced vibration of the bridge towers during construction. The numerical simulation results show that the MSPMD is practical and effective for reducing the along-wind response of the single column tower, can be installed in a small area of the tower, and complies with the time-variant characteristics of the bridge during its entire construction stage.     

Dynamic performance of angle-steel concrete columns under low cyclic loading-Ⅱ: parametric study

Tests of nine angle-steel concrete column (ASCC) specimens under low cyclic loading are described in acompanion paper (Zheng and Ji, 2008). In this paper, the skeleton curves from the numerical simulation are presented, andshow good agreement with the test results. Furthermore, parametric studies are conducted to explore the influence of factorssuch as the axial compression ratio, shear steel plate ratio, steel ratio, prismatic concrete compression strength, yield strengthof angle steel and shear span ratio, etc., on the monotonic load-displacement curves of the ASCCs. Based on a statisticalanalysis of the calculated results, hysteretic models for load-displacement and moment-curvature are proposed, which agreewell with the test results. Finally, some suggestions concerning the conformation of ASCCs are proposed, which could beuseful in engineering practice.     

Dynamic performance of angle-steel concrete columns under low cyclic loading-Ⅱ： parametric study

Tests of nine angle-steel concrete column （ASCC） specimens under low cyclic loading are described in a companion paper （Zheng and Ji, 2008）. In this paper, the skeleton curves from the numerical simulation are presented, and show good agreement with the test results. Furthermore, parametric studies are conducted to explore the influence of factors such as the axial compression ratio, shear steel plate ratio, steel ratio, prismatic concrete compression strength, yield strength of angle steel and shear span ratio, etc., on the monotonic load-displacement curves of the ASCCs. Based on a statistical analysis of the calculated results, hysteretic models for load-displacement and moment-curvature are proposed, which agree well with the test results. Finally, some suggestions concerning the conformation of ASCCs are proposed, which could be useful in engineering practice.