Experiment study and finite element analysis on mechanical performance of floor short beams
To investigate the influence of structural spatial restraint on mechanical performance of floor short beams,12 floor short beams with a span-to-depth ratio of 3.3 were designed in a frame structure with the bottom reinforcement ratio and the spatial position of beam taken as variables,and then tested in static vertical loading tests.Furthermore,the test results were compared to those of 4 simply supported short beams with the same parameters.The research results indicate that for the floor short beams,the bottom longitudinal reinforcement yields firstly and eventually splitting along the critical diagonal crack occurs,while for the simply supported short beams,the bottom longitudinal reinforcement yields firstly and the beam fails in flexural mode or shear-compression mode eventually.Compared to the simply supported short beams,the capacity of the floor short beams is increased and the ductility is decreased.The capacity of the floor short beams is positively related to the bottom reinforcement ratio and is insensitive to the spatial position of beam.The finite element models of the test frame were established for numerical simulation,the simulation results disclose that with the increase of the floor flange width of the floor short beam section,the axial compressive force tends to be uniform along the beam span.When the axial restraint stiffness of the floor short beam increases,the axial force and capacity increase,and the capacity of the floor short beam changes from dominated by flexural capacity to dominated by shear capacity.By using the capacity calculation method suggested in Chinese code,the capacity of floor short beam specimens was calculated with and without the axial force being considered,respectively.It is shown that the axial compressive force shall be considered in order to accurately determine the failure mode and capacity of the floor short beams.
floorshort beamstructural spatial restraintscapacityaxial compressive force
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