The Study Of Shear Performance Of Reinforced Concrete Columns Under Near-field Earthquake

Compared with far-field earthquakes, near-field earthquakes might cause a greater impact on structure, leading to worse damaging and stronger destructiveness. Due to various reasons, Short columns exist in practical project, and tend to be more liable to suffer damage than long columns. Also there is some difference between the two kinds of columns. Therefore it is necessary to put special emphasis on how short columns perform during near-field earthquakes, to avoid structural rupture, causing loss to human lives and properties. So far some research work have been taken by a postgraduate student about columns suffering bending failure under low cyclic loading experiments according to near-field earthquakes. In this case the research work of this paper contains four experiments concerning shear performance under a loading system considering near-field effects. Subjects of these experiments are as follow:designing and assembling of the specimens, comparing performance between columns with different height and different diameter of bars according to Near-field effects as well as fixing loading system according to each experiment, focusing a relevant measuring scheme to these experiments Comparing different effects near-field Earthquakes and far-field Earthquakes exert on the columns in these experiments. Make detailed description of the columns’ experimental phenomenon, including the first cracking of concrete, the yielding of vertical bars and horizontal hoops, the emergence and development of diagonal cracks, the phenomena of the concrete failure; Comparative analysis the test data collected, including hysteresis curve, energy dissipation, stiffness, relationship between steel and concrete, and deformation relationship between three components, bonding, shear and slipping. Verify the seismic performance of columns by comparison between each test. Some numerical simulation is done to compare the experiment results. Three damage models are used in evaluating each test. Through the comparison, advantages of each are picked out in accuracy of every stage during the experiment. At last the paper pick up a damage model fitting the damage status of a structure in the near-field earthquakes. Columns failing in bending and in shearing are also compared using damage models. Different reasons are discussed for damage formatting.