Confined Masonry Structure Seismic Performance Experimental Research

Brick masonry structure as the most common form of civil buildings in our country has following advantages:shapely to look as well as economical、convenient to construction and easy to fetch materials. Collapse of masonry buildings caused tremendous losses in the lives and properties of the people in Tangshan Earthquake (1976) and Wenchuan Earthquake (2008). After the earthquake people found that masonry buildings which used ring beam and structural column although severely damaged but not collapsed. It came to be known as confined masonry structure.Through Full-scale structure model was designed and fabricated, this paper has experimental study on the seismic peformance of confined masonry structure. This single-bay and single-depth model structure resulted in3.6mx2.4m, which had4.7m high of two floors. During the construction of the model bulding, bricks were tested for compression and compression tests were also conducted on motar cubes. Similarly, masonry prisms were tested to evaluate the masonry’s strength in shear and compression.After curing of model structure, impact tests were conducted to assess the dynamic characteristics of the model building, its contents mostly consist natural frequency, vibration mode and damping ratio. Then pseudo-dynamic test was conducted, the building was subjected to artificial earthquake acceleration. Seismic response of the model under7intensity rarely earthquake were measured through the test, it consists response acceleration, velocity, displacement and restoring force. Simultaneously, reinforcement strain of root and beam-column joint were also measured. Restoring force versus displacement hysteretic curves and drift of deflection were analyzed after the pseudo-dynamic test. The structure stays integrity, although stiffness degaration was obvious with structure strength decreased. Quasi-static test was conducted finally, in order to accurately map the cracks and observe crack propagation pattern and the failure mode of structure.The experimental results and analyzed data indicated:①the maximum value of roof’s displacement and restoring force is1.944mm and78.77kN;②the maximum value of story drift is1/2238, less than the limit value stipulate in code;③the maximum value of reinforcement strain is98.37×10-6, less than the yield strain. This study shows that under7intensity rarely earthquake, the structure has good quality of integrity and seismic performance and satisfactory for code for seismic design of buildings.