Comprehensive structural health monitoring systems have been developed and installed in several long-span suspension bridges around the world, aiming to monitor structural health conditions of the bridges in real time. Nevertheless, many key issues remain unsolved, such as how to take full advantage of the health monitoring system for effective and reliable damage detection of these complex structures. An innovative testbed was therefore established in a laboratory to allow researchers to recreate rational damage scenarios, apply different sensors and sensing networks, and test various damage detection algorithms. The design principles of the laboratory-based testbed are introduced. The paper will then outline the design and setup of a physical model for a long-span suspension bridge, which will consider various damage scenarios. Geometric measurements and modal tests were subsequently carried out to identify its geometric configuration and dynamic characteristics, respectively. The finite-element...

The nonlinear post-flutter instabilities were experimentally investigated through two-degree-of-freedom sectional model tests on a typical flat closed-box bridge deck (width-to-depth ratio 9.14). Laser displacement sensors and piezoelectric force balances were used in the synchronous measurement of dynamic displacement and aerodynamic force. Beyond linear flutter boundary, the sectional model exhibited heave-torsion coupled limit cycle oscillation (LCOs) with an unrestricted increase of stable amplitudes with reduced velocity. The post-critical LCOs vibrated in a complex mode with amplitude-dependent mode modulus and phase angle. Obvious heaving static deformation was found to be coupled with the large-amplitude post-critical LCOs, for which classical quasi-steady theory was not applicable. The aerodynamic torsional moment and lift during post-critical LCOs were measured through a novel wind-tunnel technique by 4 piezoelectric force balances. The measured force signals were found to contain significantly higher-order components. The energy evolution mechanism during post-critical LCOs was revealed via the hysteresis loops of the measured force signals.