为研究钢-混组合梁中剪力钉在不同温度场下的抗拔破坏模态和承载力,以某铁路桥钢-混组合梁为基础设计剪力钉试件,采用Abaqus软件建立试件有限元模型,分析剪力钉试件在双面受火、混凝土单面受火和钢板单面受火3种形式下的抗拔破坏模态、荷载~位移曲线和承载力,并根据承载力结果拟合不同温度下剪力钉的抗拔承载力计算公式.结果表明:钢-混组合梁在常温下和混凝土单面受火时,其受拉破坏模态为混凝土脆性破坏、剪力钉被整体拉出;在双面受火约10 min后,其受拉破坏模态变为剪力钉的延性断裂;钢-混组合梁双面受火时,剪力钉的抗拔承载力在短时间内就会受温度影响急剧下降,30 min后下降速度变慢,受火15,30,180 min时,其抗拔承载力比常温时分别下降33.2%、59.1%、79.1%;混凝土单面受火时,剪力钉的抗拔承载力随受火时间下降较慢,受火180 min时,其抗拔承载力比常温时下降10.2%.%To study the pullout failure modes and pullout capacity of the shear studs in the steel and concrete composite girder in the different temperature fields,a shear stud specimen was designed based on the steel and concrete composite girder of a railway bridge and the finite element model for the specimen was established,using the software Abaqus.The pullout failure modes, load~displacement curves and pullout capacity of the specimen under the 3 situations that the specimen was subjected to the fire on the two sides,the concrete was subjected to the fire on the one side and the steel plate was subjected to the fire on the one side were analyzed and the calcula-tion formula for the pullout capacity of the shear stud under the different temperatures was fitted in terms of the analysis of the capacity.The results demonstrate that under the normal tempera-ture and the situation that the concrete is subjected to the fire on the one side,the tensile failure mode of the composite girder is the brittle failure of the concrete and the shear studs in the girder are integrally pulled out.After about 10 min when the girder is subjected to the fire on the two sides,the tensile failure mode changes into the ductile breaking of the shear studs.When subjected to the fire on the two sides,the pullout capacity of the shear studs drastically decreases in the short time due to the influences of the temperatures and after 30 min of the fire,the decreasing speed of the pullout capacity slows down.When subjected to the fire of 15,30 and 180 min,the pullout capacity of the shear studs respectively decreases by 33.2%,59.1% and 79.1% as com-pared to the girder under the normal temperature.When the concrete is subjected to the fire on the one side,the decrease of the pullout capacity changing with the fire time is slow and at 180 min of the fire,the pullout capacity decreases by 10.2% as compared to the girder under the normal tem-perature.
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