Study On Seismic Performance Test And Comprehensive Modification In Rural Housing

Abstract:In order to improve the seismic and thermal insulation performance of the rural houses in Beijing, a large amount of researches and structural characteristics analysis have been finished, which lead to the comprehensive modification methods for these rural houses. The classification of typical structures, the research of seismic performance, the strengthening methods and optimization have been figured out during the preliminary research. The shaking table tests of seismic strengthening of engineering and prototype models, components under low reversed cyclic loading test, material tests and numerical simulation analysis have been done in order to comparatively analyze the damages and crack development, dynamic performance such as structure frequency and damping characteristics, hysteresis curves and stiffness degradations. These experiments and researches verified the significance and practicability about strengthening methods and energy-saving comprehensive modification. The strengthened models have reached the seismic fortification goals. This dissertation mainly researches in the following aspects:(1) Based on a large amount of preliminary researches, the structural characteristics of rural housing in Beijing have been summed up and the existing problems about seismic performance have been pointed out. The seismic strengthening for engineering plans within the goals and methods have been figured out.(2) Three pieces of wall under low reversed cyclic loading pseudo-static tests have been finished according to the seismic strengthening for engineering plan and combination with different strengthening methods and materials come up with crack development and damages during the test. From the comparison analysis about skeleton curves, displacement, hysteresis curve, stiffness degradation and energy dissipation, come to the seismic performance and capacity between different strengthened walls.(3) The shaking table test is focused on the typical three-bay single layer rural house built with wood and brick in Beijing. One prototype model and two strengthened models with different reinforcement methods have been built to simulate their response when subjected to horizontal seismic wave about8degrees (0.072g),8degrees (0.2g) and8degrees (0.4g). The experiments concluded and testified the seismic performance and the effectiveness between the prototype model and strengthened models by analyzing the seismic response, structural frequency and damping ratio, structural damage and cracks develop.(4) Modal analyses about shaking table models have been finished by using SAP2000software. The results come up with frequencies and mode shape. The impact and deviation between different ways of loading have been analyzed by computer simulation.(5) The simplified calculation method about lateral stiffness of longitudinal wall has been figured out in this study, which solved the quantitative calculation of the lateral stiffness of the longitudinal wall when doing the practical strengthening design. It is important to determine the strengthening methods and minimize the lateral stiffness differences between front and rear vertical wall. The ultimate bearing capacity calculation formula has been figured out for original and strengthened brick masonry wall.(6) The pilot project houses have been rebuilt based on the experimental models and typical structure shape of rural house. In accordance with the structural features of pilot projects, we designed the seismic strengthening of engineering and energy-saving comprehensive modification plan, and organized the construction. The modification performance and economy have been analyzed according to the modification experiences. The pilot projects played an important role as demonstation examples for future application and promotion.The study puts forwards the steel ring beam first, which is a strengthening method in order to improve the integrity, and testified by the shaking table test. The study proposed two strengthening methods for front longitudinal wall to solve the large different stiffness of the front and rear wall which is caused by the opening in the front wall. The methods are adding steel door/window frame and concrete door/window frame, both of which have been patented.The results and conclusions in this study play an important technical support in the seismic strengthening of engineering and energy-saving comprehensive modification in Beijing, even all over the country. The comprehensive modification methods in this study are the major methods accepted and used by "The Guideline for Comprehensive Modification of Beijing Rural Residential Buildings (Single-storey House)", also an important technical support for the local standard in Beijing which is now compiling.