884aa四虎影成人精品,99久久国产综合精品女图图等你,97在线观看永久免费视频,久久精品国产精品亚洲38,ⅵdeodesetv性欧美

（中冶建筑研究總院有限公司， 北京 100088)

［摘要］為研究緩粘結(jié)預(yù)應(yīng)力鋼絞線與混凝土之間粘結(jié)性能，對3根截面尺寸相同、普通鋼筋配筋相同、預(yù)應(yīng)力不同的混凝土梁進(jìn)行了試驗(yàn)研究，重點(diǎn)研究了不張拉、不錨固鋼絞線預(yù)應(yīng)力混凝土梁的荷載-位移關(guān)系、裂縫分布規(guī)律、最大裂縫寬度隨荷載的變化規(guī)律、鋼絞線內(nèi)的應(yīng)力大小、鋼絞線與混凝土之間的粘結(jié)強(qiáng)度等，與不配預(yù)應(yīng)力筋的普通鋼筋混凝土梁和配筋相同的普通預(yù)應(yīng)力混凝土梁的受力進(jìn)行了對比分析。試驗(yàn)表明，緩粘結(jié)預(yù)應(yīng)力鋼絞線與混凝土之間有良好的粘結(jié)性，粘結(jié)強(qiáng)度與混凝土咬合處剪切破壞強(qiáng)度相吻合；利用粘結(jié)作用和一定傳遞長度，不張拉、不錨固鋼絞線預(yù)應(yīng)力可以達(dá)到1 100MPa以上，考慮承載力檢驗(yàn)系數(shù)后鋼絞線應(yīng)力設(shè)計(jì)值可取800MPa；不張拉、不錨固預(yù)應(yīng)力混凝土梁的彎曲裂縫分布與普通預(yù)應(yīng)力混凝土梁基本相同，破壞時端部產(chǎn)生的鋼絞線滑動引起沿鋼絞線方向的裂縫，進(jìn)一步證明粘結(jié)破壞是混凝土的剪切破壞而非粘合劑破壞。

［關(guān)鍵詞］緩粘結(jié)預(yù)應(yīng)力； 鋼絞線； 張拉； 錨固； 粘結(jié)強(qiáng)度； 粘結(jié)破壞

中圖分類號：TU378-1文獻(xiàn)標(biāo)識碼：A文章編號：1002-848X(2020)02-0056-05

Experimental study on cohesive property of steel strand in retard-bonded prestressed concrete beams

Shang Renjie， Tian Junyuan， Yang Xiao

(Central Research Institute of Building and Construction Co. Ltd, MCC Group, Beijing 100088, China）

Abstract:In order to investigate the cohesive property between retard-bonded prestressed steel strand and concrete, experimental studies were conducted on 3 specimens with same cross-section, same reinforcement and different prestresses. The study focused on the results of non-tensioned and non-anchoraged prestressed concrete beams, including load-displacement curve, distribution of cracks, relationship between loading and, stress of the steel strand, cohesive strength between steel strand and concrete. The results were compared with those of common reinforced concrete beams without prestressing tendon and common reinforced concrete beams with the same ratio of prestressing tendon. The experiments show that cohesive property between retard-bonded prestressed steel strand and concrete is good, and the cohesive strength agrees well with the shear strength of the concrete at the interlock section. The prestress in the steel strand without tensioning and anchorage can reach more than 1 100MPa by means of cohesive stress and certain transfer length, and the design value of the steel strand stress can be evaluated as 800MPa when considering bearing capacity test coefficient. The distribution of the bending cracks of non-tensioned and non-anchoraged prestressed concrete beams is basically the same to that of the common prestressed concrete beam, and cracks along the direction of the strand caused by the sliding of the strands appeared at the end of the beam after the failure. It is conformed that the cohesive failure features the shear failure of concrete rather than the adhesive failure.

Keywords:retard-bonded prestress; steel strand; tensioning; anchoring; cohesive strength; cohesive failure