The Test On Seismic Performance Of The Dalun Cavity Walls With Different Constructional Measures And Different Reinforcements

On February 9,2006, a series of perceptible earthquake occurred in Wencheng County (earthquake—unresistance) and Taishun Country (the sixth degree earthquake—resistance protection zone) of Zhejiang Province, which damaged 99383 houses and affected population of more than 140000 people, the property loss more than 200 million yuan. Through the survey, we understood that a lot of buildings on the quake—hit region used the cavity wall as load—bearing structure. The cavity walls were built by special brick named DaLun brick, the DaLun brick is different from the brick of standard, so we should do a special research on how to strengthen the buildings built by DaLun bricks to resist the earthquake. Wenzhou Construction Bureau with some institutions tested 13 walls in the mechanics laboratory of Zhejiang University. In this paper, the major work done as follows:The essay studies the compressive property and the shearing property of the hollow brick masonry. Based on the experiment of three different groups (six samples in one group) of samples built by mortars of different strength classes, the essay analyses the bearing capacity of compressive. Based on the experiment of two different groups (three samples in one group) of samples under the different compressing stresses, the essay analyses the shear strength and the relationship between the shear stress and the compressive stress. On the basis of experiments, this essay sets up the proper FEA model, derives the calculation method of the compressive strength of the hollow brick masonry.In this thesis, the experiments are carried out to study on the seismic behavior of 13 specimens of three constructional measures and three strengthening modes under the cyclic loading, including the position of the initial crack, the fracture morphology development law of the crack, the lateral load—bearing capacity of the wall, the hysteretic curve and the skeleton—frame curves of the wall and ductility performance, etc. The results reveal that the seismic performance of the cavity wall with some construction measures reinforced by cement mortar reinforced with steel mesh is obviously improved.At the villages and small towns (The seismic design intensity of the major area is above 6 degree) in our country, there are lots of buildings carrying the cavity walls as load—bearing structure. Despite some buildings are not located on earthquake—resistant zone, there still have lots of potential safety problems, and these research conclusions provide the basis for earthquake—resistant improvement measure of the cavity brick masonry.