Shaking Table Test And Damage Mechanism Study On Seismic Strengthening Of Single-layer Brick-wood Structure

At present,the masonry structure widely exists in China 's villages and towns,and a considerable number of them are not fortified or fortified.Earthquake resistance,through reinforcement and demolition,etc.,to improve the safety of houses with insufficient earthquake resistance,continue to implement the reconstruction of rural dilapidated houses,and coordinate the advancement of the earthquake-resistant reinforcement of rural houses.On the basis of in-depth investigation and comparative research,based on the principles of high efficiency,economy,environmental protection,and reliability,a new seismic strengthening plan for single-storey brick-wood mixed loadbearing structural houses in Beijing was proposed.The main contents of the plan include: After the brick wall is adopted Tensile prestressed reinforcement,reinforced mesh mortar with ring beams and structural columns are added to the whole house,steel tie rods are added to the front longitudinal wall,and scissors supports are added between the roof truss.A comparative test was conducted to simulate the seismic shaking table using the new scheme of reinforced and unreinforced 1 / 2-scale house models to study the damage form,energy dissipation performance,stiffness degradation,and displacement changes of the house model under the earthquake conditions of different working conditions.Indicators such as acceleration changes.Experimental research shows:(1)The unreinforced model has a fortification intensity of less than 8 degrees,the reinforced model has only slight cracks under the action of an 8-degree earthquake,and the dynamic response indicators are relatively small.The reinforcement scheme improves the model's ability to resist collapse under large earthquakes.(2)The initial damping ratio of the reinforced model has increased,the energy dissipation effect of the structure is obvious,and the stiffness degradation has been improved.(3)The maximum interlayer displacement angle in the X direction of the model before and after the reinforcement under the action of an 8-degree earthquake reaches 1/83 and 1/229,respectively.Anti-seismic "shocks do not fall" fortification requirements.On the basis of the experimental research,the finite element software MSC.Marc was further used to perform nonlinear dynamic time history analysis and Pushover static pushover simulation analysis on the test model.The results of finite element simulation analysis show that:(1)The reinforcement scheme can significantly improve the torsional effect of the single-layer brick-wood mixed load-bearing structural house with weak front face rigidity,and effectively suppress the structural deformation.(2)The ratio of the bottom shear force in the X and Y directions of the reinforced and unreinforced models is 1.35 and 1.24,the corresponding displacement values are increased by 58% and 32%,and the shear capacity and ductility of the structure after reinforcement are improved.(3)The location,time,development speed and final failure state of the initial cracks in the model before and after reinforcement are obviously different.The reinforcement scheme greatly improved the damage pattern,and more damage was involved in energy consumption.The research done not only provides new ideas for the popularization and application of post-tensioned prestressed reinforcement technology,but also provides theoretical guidance and scientific basis for the reinforcement of existing masonry structures in villages and towns throughout the country,especially in Beijing.