大直徑高強(qiáng)鋼絞線預(yù)應(yīng)力混凝土梁受力性能

王鈞+李婷+任靖豪

摘要：為探討大直徑高強(qiáng)鋼絞線預(yù)應(yīng)力混凝土梁的受力性能，進(jìn)行了6根以直徑17.8 mm的1860級鋼絞線作為預(yù)應(yīng)力鋼筋和HRB400級鋼筋作為非預(yù)應(yīng)力鋼筋的后張預(yù)應(yīng)力混凝土梁在豎向荷載作用下的受力性能試驗(yàn)。對預(yù)應(yīng)力混凝土梁中鋼絞線和非預(yù)應(yīng)力鋼筋應(yīng)力、混凝土應(yīng)變以及短期最大裂縫寬度和跨中撓度等試驗(yàn)數(shù)據(jù)進(jìn)行分析。結(jié)果表明：采用大直徑高強(qiáng)鋼絞線作為預(yù)應(yīng)力鋼筋的預(yù)應(yīng)力混凝土梁工作性能良好，大直徑高強(qiáng)鋼絞線預(yù)應(yīng)力混凝土梁受彎破壞形式和撓曲模式與普通預(yù)應(yīng)力混凝土梁基本相同；試驗(yàn)梁跨中控制截面符合平截面假定，極限承載力可按照現(xiàn)行規(guī)范的正截面抗彎理論計(jì)算，按照現(xiàn)行規(guī)范計(jì)算的試驗(yàn)梁裂縫寬度和撓度與實(shí)測值吻合較好。

關(guān)鍵詞：大直徑高強(qiáng)鋼絞線；預(yù)應(yīng)力混凝土梁；極限承載力；裂縫寬度；剛度

中圖分類號：TU378.2 文獻(xiàn)標(biāo)志碼：A

文章編號：1673-2049（2017）02-0103-08

Abstract：In order to explore the mechanical performance of prestressed concrete beam with large-diameter high-strength steel strand， the stress performance tests of six post-tensioning prestressed concrete beams under vertical loads were conducted. The prestressed concrete beams were made of 1860 grade steel strand with 17.8 mm diameter as prestressed reinforcement and HRB400 grade steel bars as non-prestressed tendons. The test data about pre-stressed concrete beam， such as the stress of steel strand and non-pre-stressed reinforcement， concrete strain， maximum crack width in short term， mid-span deflection and so forth were analyzed. The results show that the work performance of prestressed concrete beam with large-diameter high-strength steel strands as prestressed reinforcement is well. The flexural failure form and flexural mode of prestressed concrete beam with large-diameter high-strength steel strand is almost same with ordinary pre-stressed concrete beam. The mid-span control section of test beam meets the plane cross-section assumption， and the ultimate bearing capacity can be calculated according to the specification of normal section bending theory. The calculated crack width and deflection of test beam according to current specification agree well with the measured value.

Key words：larger-diameter high-strength steel strand； prestressed concrete beam； ultimate bearing capacity； crack width； stiffness