Research On Foundation Stiffness Influence The Stress Mechanism Of Ancient Masonry Tower Structure

In recent years, The methods of adding a beam (hoop beam) to improve the stressstate of the tower body, a ground beam and rigid tray to adjust distribution of basestress have been found in engineering practice. However, there were few studies on thedistribution with changed foundation stiffness of the tower bottom counterforce,dynamic characteristics that taking into account collaborative action of the additionalfoundation and tower body, seismic response and stability of the tower body.This paper takes a tower as an object of study combined with the reinforcementprotection engineering, through the methods of in-situ testing, theoretical analysis andnumerical simulation. The stress mechanism and seismic response under differentfoundation stiffness of rectification and reinforcement of masonry tower are comparedand analysed, the main contents are as follows:1.The dynamic test is made on masonry tower by pulsating method, Thefrequency, vibration mode and amplitude of first four order are obtained. On thesebases, the numerical analysis model is established, the physical and mechanicalparameters of the tower body is calculated by the inversion method.2. The space co-interaction work analysis models with foundation and tower bybuilding RC beam, RC beam-ground beam, RC rigid tray are established. Throughnumerical calculation for the three different foundation, the dynamic characteristics ofthe tower body, the stress distribution, load paths of dangerous section, seismicresponse are compared and analysed. The results show that: with foundation stiffnessincreases, the counterforce of tower bottom tends to be uniform, the stress peak value of tower body decreases. The increasing foundation stiffness is good to improve thetower body’s stability. While foundation stiffness increases, with synergistic action offoundation and tower body, the natural vibration period decreases, the frequencyincreases, the amplitude decreases.3. The paper analyses the responses of the three different foundation stiffnessconditions under frequent earthquake. The results show that: with the foundationstiffness increases, displacement of the tower increases, while the stress peak value oftower bottom decreased.