疲勞荷載作用下植筋錨固粘結的滑移性能

閻西康 梁琳霄 梁琛

摘 要： 為研究疲勞荷載對植筋拉拔承載力、粘結應力的影響，設計植筋直徑為16～25 mm、錨固深度為10d～25d（d為植筋直徑）的10組拉拔試件進行疲勞試驗，試件經200萬次荷載上限為0.45Pu的疲勞加載后均未破壞，施加靜載至破壞。加載過程中測量植筋的應變、滑移和荷載。結果表明：疲勞荷載削弱了承載能力，試件經疲勞荷載作用后極限承載力下降，粘結應力的減小隨循環加載次數增加呈對數發展趨勢。分析了粘結應力與試件破壞形態的關系。對于拔出破壞的試件，達到一定植筋深度后，膠筋界面的粘結應力是控制試件破壞與否的主要因素。增加植筋直徑和錨固深度，粘結應力峰值逐漸降低，沿錨固長度的應力分布曲線趨于平緩，提高了植筋整體受力性能。

關鍵詞： 植筋;疲勞荷載;粘結應力;疲勞性能

中圖分類號：TU375.1? ? 文獻標志碼：A? ?文章編號：2096-6717（2020）02-0149-08

Bond slip behavior of post-installed anchorage under fatigue load

Yan Xikang1， Liang Linxiao1， Liang Chen2

（1.School of Civil and Transportation Engineering， Hebei University of Technology， Tianjin 300401， P.R.China;2.China State Construction Land （Tianjin）Co. Ltd， Tianjin 300450， P.R.China）

Abstract：? Through the fatigue test of 10 groups of drawing specimens with diameter of planting reinforcing bar of 16～25mm and embedment depth of 10d～25d （d is diameter of planting reinforcing bar ）， effect of fatigue load on tensile strength and bond stress of anchor bars had been studied.The specimens were not damaged after 2 million times of fatigue loading with an upper limit of 0.45Pu， then applied static load to failure.Strain， slip and load of planted bars are measured during loading.Results demonstrate that the fatigue load weakens tensile strength， and the ultimate load decreases after fatigue loading.The decrease of bond stress has a logarithmic trend with the increase of cyclic loading times.The relationship of the bond stress and the failure form of the specimen is analyzed.It is found that the bond stress at the interface between rebar and chemical adhesive is the main factor to control whether the specimen failure or not when reaching certain embedment depth.Increasing the diameter and embedment depth of anchor bar， the peak of bond stress gradually decreases; the stress distribution curve along the embedment length tends to be gentle， which improves the overall stress performance of the anchor bar.

Keywords： planting reinforcing bar; fatigue load; bonding stress; fatigue behavior

隨著承受疲勞荷載的結構如吊車梁、橋梁等的維修、改造工程日益增多，植筋技術在這方面的應用研究愈加廣泛[1-2]。植入鋼筋的粘結滑移性能是保證植筋結構穩定安全的關鍵因素[3-5]，部分學者對靜載作用下植筋與混凝土界面、植筋與植筋膠界面的結合性能做了一定研究，主要集中在植筋直徑、混凝土材料強度、保護層厚度、施工質量等因素對植筋粘結強度的影響[6-7]。Wang等[8-9]對直徑36～150 mm的螺桿錨固破壞形式進行分析，給出了大直徑植筋系統拉拔承載力計算公式。植筋拉拔試件在高溫環境中的力學性能研究表明，溫度對植筋拉拔滑移的影響較大[10]。……