doi:10.16186/j.cnki.1673-9787.2023100025

Received:2023-10-11

Revised:2023-12-05

Online Date: 2023-12-06

Stiffness analysis of partially filled narrow steel box-UHPC composite beam under negative moment（Online）

MO Shixu1,2, CHAI Longjie1, ZHENG Yan1,2, HUANG Yijun1, TAN Xinning1

1.College of Civil Engineering and Architecture， Guilin University of Technology， Guilin  541004， Guangxi ，China；2.Guangxi Key Laboratory of Green Building Materials and Construction Industrialization， Guilin  541004， Guangxi， China

Abstract:In order to study the flexural properties of partially filled narrow steel box-UHPC composite beams under negative moment， static load tests were carried out on 9 composite beams with reverse concentrated force. Based on the different steel fiber content， reinforcement ratio and relative filling height， the influence on the loading process， strain behavior， stiffness and crack resistance of the partially filled narrow steel box-UHPC composite beam is studied. The test results show that compared with the partially filled narrow steel box-NC composite beam and the narrow steel box-UHPC composite beam， the ultimate bearing capacity， serviceability and ultimate limit stage stiffness of the partially filled narrow steel box-UHPC composite beam increase by 57%， 25% and 21%. When the crack width is 0.05 mm， 0.1 mm， 0.2 mm， the corresponding load increases by 155%， 266% and 100%. The deflection of composite beam under the action of negative moment is too conservative due to ignoring the influence of slip. The deflection of the test beam was calculated according to the effective moment of inertia method considering the sliding effect of the composite beam under the action of negative moment and was more accurate.

Key words:partially filled narrow steel box-UHPC composite beams;ultra-high performance concrete （UHPC）;ultimate bearing capacity;deflection;crack width

CLC: TU398⁺.9