预应力锚固体系锚垫板上灌浆孔的研究

Study of Grouting Hole on Anchor Plate of Prestressed Anchorage System

在预应力锚固区及其锚垫板的结构设计研究中,为了提高模型分析运算速度,通常简化模型结构而忽略灌浆孔,进而忽略了灌浆孔对预应力锚固区应力分布的影响。本文以设置灌浆孔的锚垫板旋转角度为变量,对铸造型锚垫板上的灌浆孔展开研究,建立2 200 MPa级预应力锚固区模型进行有限元分析,确定锚垫板的最佳放置位置,然后进行锚固区传力试验。结果表明:锚垫板放置在45°位置,锚固区承载力相对较高,锚固区安全可靠。由于灌浆孔的存在,锚垫板应力集中出现在灌浆孔,因此建立拉压杆模型对锚垫板进行结构设计时需忽略灌浆孔。与未设置灌浆孔相比,设置灌浆孔的锚垫板主拉应力最大增加了34.27%,主压应力最大增加了4.81%。螺旋筋主拉应力最大减少了4.16%,Von-Mises应力最大减少了16.83%,锚下混凝土侧表面拉应力最大增加了1.99%。试验结果验证了锚垫板放置在45°位置时2 200 MPa级预应力锚固区结构安全。

In the structural design research of prestressed anchorage zone and its anchor plate,to improve the speed of model analysis calculation,the model structure is usually simplified while ignoring the grouting holes,and thus the influence of grouting hole on the stress distribution of prestressed anchorage is also ignored.In this paper,the rotation angle of the anchor plate with grouting hole was used as a variable to study the grouting hole in anchor plates,a 2200 MPa level prestressed anchoring zone model was established to determine the optimal placement position of the anchor plate.The force transfer test was carried out in the anchorage zone.The results indicate that when the anchor plate is placed at a 45°position,the bearing capacity of the anchorage zone is relatively high,and the anchorage zone is safe and reliable.Due to the presence of grouting hole,stress concentration on the anchor plate occurs at the grouting hole.Therefore,when establishing a strut-and-tie model for the structural design of the anchor plate,grouting hole need to be ignored.Compared with the anchor plate without grouting holes,the maximum principal tensile stress of the anchor plate with grouting hole increased by 34.27%,and the maximum principal compressive stress increased by 4.81%.The maximum principal tensile stress of spiral reinforcement decreased by 4.16%,the maximum Von-Mises stress decreased by 16.83%,and the maximum tensile stress on the side surface of the anchored concrete increased by 1.99%.The experimental results have verified that the structure of the 2200 MPa level prestressed anchorage zone is safe when the anchor plate is placed at a 45°position.