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Vertical Push-down Tests of RC Beams at High Temperature Considering Axial Restraint(PDF)

《建筑科学与工程学报》[ISSN:1673-2049/CN:61-1442/TU]

Issue:
2020年01期
Page:
41-48
Research Field:
Publishing date:

Info

Title:
Vertical Push-down Tests of RC Beams at High Temperature Considering Axial Restraint
Author(s):
HUO Jing-si12 HAO Bai-qing1 LI Zhi1
(1. Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education, Hunan University, Changsha 410082, Hunan, China; 2. Fujian Provincial Key Laboratory of Intelligent Infrastructure and Monitoring, Huaqiao University, Xiamen 361021, Fujian, China; 3. LERA Consulting Structural Engineers, New York NY10005, USA)
Keywords:
reinforced concrete beam axial restraint high temperature large deformation failure mode
PACS:
TU375.1
DOI:
10.19815/j.jace.2018.11069
Abstract:
In order to investigate the influence of axial restraint on the mechanical behaviours of fire-exposed reinforced concrete(RC)beams at large deformation, the push-down tests of one restrained beam at ambient temperature and two restrained beams at high temperature were carried out. The effects of different heating time on the measuring point temperature, heating response, ductility and energy dissipation of axially restrained RC beams were compared and analyzed. The thermal response, failure mode, bearing capacity and force mechanism of axially restrained RC beams were mainly studied. The results show that during the heating process, with the increase of temperature, the axially restrained RC beams deflect downward continuously, but the deflection recovers after the furnace temperature exceeds 800 ℃. Due to the influence of axial compression caused by thermal expansion, the plastic hinge area of restrained beams at high temperature is obviously reduced, and its ductility and energy dissipation capacity decrease with the increase of temperature. The initial axial compression caused by high temperature increases the peak bearing capacity of beams, but with the increase of heating time, the increase amplitude is less than the decrease amplitude of peak bearing capacity of beams caused by material deterioration. The initial axial compression makes high temperature beams always in bending mechanism before failure. The paper can provide reliable experimental data for verifying and modifying the numerical simulation as well as theoretical analysis of the mechanical behavior of confined concrete beams under fire, and provide a basis for further exploring the failure criteria of axially restrained RC beams under large deformation at high temperature.

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Last Update: 2020-01-13