摘要
预制装配式先张折线预应力T梁因具有承载能力高、抗裂性能好、施工速度快等优点,在中小跨径桥梁结构中具有广泛的应用前景。设计了一种新型30 m,跨先张折线预应力T型梁,并通过足尺静力试验研究了其在扭转作用下的性能,包括变形能力、应变分布、抗裂性能和裂缝发展规律等。试验结果表明:试验梁在扭转作用下的受力过程分为弹性阶段和裂缝开展阶段。裂缝优先出现在端部上翼缘与腹板交界处和加载截面底部下翼缘处,随后试件腹板立面出现较多斜裂缝和弯剪裂缝,同时顶面开始出现斜裂缝,裂缝位置也逐渐向支座截面扩展;弯曲裂缝的出现会使底部纵筋的应变发生突变,腹板混凝土出现斜裂缝后箍筋应变和混凝土应变发生突变,箍筋上部相比中下部应变峰值更大,加载底部与支座上部连线附近的主应变峰值较大;根据ACI 318—19规范计算的开裂扭矩为777 k N·m,与测试值的比例系数为1.16,表明先张折线预应力混凝土T型梁具有良好的抗裂性能。为先张折线预应力T梁在扭转作用下的损伤过程与结构优化提供了重要参考。
Precast prestressed beams,characterized by high load-bearing capacity,excellent crack resistance,and rapid construction speed,show great potential for application in medium and smallspan bridge structures.A novel 30-meter-span pre-tensioned polyline prestressed T-beam was designed,and its structural performance under torsionloading was investigated through a full-scale static loading test.This study focused on deformation capacity,strain distribution,crack resistance,and crack development patterns.The experimental results indicate that the loading process of the test beam under bending-shear-torsion coupling can be divided into the elastic stage and the crack development stage.Cracks initially appeared at the junction of the top flange and web at the beam ends,as well as at the bottom of the bottom flange at the loading section.Subsequently,numerous diagonal and bending-shear cracks were observed on the vertical face of the web,while diagonal cracks started to form on the top surface.The cracks also progressively extended toward the support section.The emergence of bending cracks caused a sudden change in the strain of the bottom longitudinal reinforcement.Once diagonal cracks appeared in the web concrete,both stirrup and concrete strains exhibited abrupt changes.The strain peaks in the upper part of the stirrups were higher than those in the middle and lower parts,with the largest strain peaks occurring near the line connecting the bottom of the load and the upper part of the support.The cracking load of the specimen,calculated based on the ACI 318—19 code,is approximately 777 kN·m,with a ratio of 1.16 to the measured value.This indicates that the test beam possesses excellent crack resistance capacity.It provides significant insights for the damage mechanisms and structural optimization of pre-tensioned polyline prestressed T-beams under torsional loading conditions.
作者
陶敬林
姚增博
余丁浩
李钢
祝林盛
裴辉腾
TAO Jinglin;YAO Zengbo;YU Dinghao;LI Gang;ZHU Linsheng;PEI Huiteng(Jiangxi Ganyue Expressway Co.,Ltd.,Nanchang 330025,China;Jiangxi Communications Investment Group Co.,Ltd.,Nanchang 330108,China;State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China;Shanghai Municipal Engineering Design Institute(Group)Co.,Ltd.,Shanghai 200092,China;Jiangxi Communications Designand Research Institute Co.,Ltd.,Nanchang 330029,China)
出处
《混凝土》
北大核心
2025年第10期153-157,166,共6页
Concrete
基金
江西省交通运输厅科技项目(2024ZG001)
国家自然科学基金(52225804)。
关键词
桥梁工程
抗裂性能
试验研究
预应力混凝土T梁
足尺模型试验
bridge engineering
cracking resistance
experimental investigation
prestressed concrete T-beam
full-scale experiment
