CFRP筋增强板加固石梁受弯性能试验研究

为实现在不明显改变被加固构件外观的同时方便现场施工操作，提出了用于既有传统素石梁抗弯加固的预制CFRP筋增强板加固技术。进行了3根采用CFRP筋增强板加固的石梁试件和1根素石梁对比试件的受弯性能试验研究，主要试验参数为CFRP筋配筋率和石梁底面粗糙程度。结果表明：CFRP筋增强板加固技术显著改善了石梁的脆性破坏形态，有效提高了石梁的受弯承载力和变形能力；随着CFRP筋用量的增大，试件受弯承载力提高，加固效果更加显著；石梁底面粗糙度对加固石梁受弯性能的影响较小，机切与凿毛界面均可满足加固需求。试验过程中，CFRP筋增强板与被加固石梁之间的界面黏结性能较好，CFRP筋端部未出现滑移现象，确保了加固试件各部分的共同工作性能。石材的离散性较大，实际工程中应增加对石材材质的检测，避免出现使用较差材质石材产生的安全隐患。

Experimental study on flexural behavior of stone beams strengthened with prefabricated CFRP-reinforced stone sheets

In order to realize the convenience of on-site construction operation while without obviously changing the appearance of the reinforced components, a new type of strengthening technique was proposed for improving the flexural performance of stone beams by using prefabricated CFRP-reinforced stone sheets. Three stone-beam specimens enhanced with such prefabricated strengthening sheets and one bare stone beam specimen were tested under bending. The main test parameters were the amount of CFRP bars and the roughness of the bottom surface of the stone beams. The tests results show that, the prefabricated strengthening sheets could change the failure of a stone beam from brittle fracture to ductile failure, and effectively increased the bearing capacity and deformation capacity. The flexural strength and reinforcement effect of the strengthened stone beams increase with an increase in the CFRP reinforcement ratio. The flexural behaviour of the strengthened stone beams is insignificantly influenced by the roughness of the bottom surface of the stone beam. The interface of machine cutting and gouging both can meet the reinforcement requirements. During the testing, good bond behaviour was achieved between the prefabricated strengthening sheet and the stone beam, and no end-slip in the CFRP bars was observed, ensuring composite actions between the different components. The variability of the properties of stone materials is relatively large, so the necessity of detection of stone materials should be highlighted in practical projects to avoid the potential hazards caused by poor properties.