Experimental Study Of Polymer Concrete Used For Structural Vibration Mitigation

With the rapid development of high-speed railway in our country, especially, the occurrence of new composite-system bridge like Wuhan railway station on Wuhan-Guangzhou Passenger Dedicated Line, how to decrease the vibration of bridge and railway station when high-speed trains passing through a bridge has become very important and challenging issue. However, damping installations are mostly appended to mitigate vibration by increasing the damping of structures. Damping installations which are able to effectively control the vibrations of structures, inevitably make structural design and construct inconvenient, and frequently affect normal function of the structures (available space of buildings). Therefore, this thesis, based on the current research of the polymer concrete, strives to resolve the contradiction betweens other properties and the damping property of normal concrete by changing the amount of polymer and controlling the composition of raw materials. The polymer-modified concrete could improve the damping properties of concrete and the dynamic system behavior of structure to achieve the desired effect of structural vibration mitigation in the condition that it do not have a negative impact on damage process and other properties. With this purpose, the main completed research works in this thesis are as follows:â‘ All sorts of damping identification methods based on modal parameter identification theory were introduced and discussed in detail: the frequency domain method and the time-domain method. Finally, Stochastic Subspace Identification Method (SSI), which used in this thesis for damping identification of polymer concrete, was emphatically discussed.â‘¡Studied the mechanical property of polymer-modified concrete with different contents of polymer through experiments to investigate the effect of content on the basic material performance of concrete (including the elastic modulus and compressive strength) and construction performance, and prepare concretes of different ratios for structural vibration-mitigation which should also reach the design standards and meet the need of project.â‘¢A series of experiments including vibration test, static loading and fatigue loading were carried out on simple beams and reduced scale models of a real long span box girder, to compare damping, the static and fatigue performance of ordinary concrete and polymer concrete.â‘£Using finite element method (FEM) simulation, carried on harmonic analysis and time history analysis to polymer concrete simple-supported box-girder beams to conclude that polymer concrete can used for structural vibration-mitigation and its effect is better than common concrete.The prepared polymer concrete (carboxy butadiene styrene polymer-modified concrete) in this thesis can increase the damping properties of concrete structure very effectively. The damping ratio of concrete structure increases with the increasing ratio of polymer and cement, while the compression strength and static modulus decrease a little but meet the code requirement. The static performance of the polymer concrete beams is better than that of the ordinary concrete beam, and the fatigue behavior of the former is the same as that of the latter. The workability of the polymer concrete including slump and slump flow is good.