缓粘结预应力混凝土梁抗裂和裂缝闭合性能

Cracking performance and crack closing of retard-bonded prestressed concrete beams

为便于施工操作保证结构质量.配制出满足后张法有粘结预应力混凝土的缓凝砂浆.通过21根缓粘结部分预应力混凝土梁的抗裂试验和裂缝闭合试验,得到了缓粘结部分预应力混凝土梁在静载条件下的开裂强度和裂缝闭合强度;分析了缓粘结部分预应力混凝土梁在等幅重复荷载作用下正截面疲劳抗裂的S-N曲线.建议实际混凝土构件的抗裂强度折减系数为0.55.对试验梁进行了结构静力计算和疲劳验算,比较了理论计算与试验结果的关系.建议部分预应力混凝土梁的静力计算方法,计算结果与试验结果吻合较好.

To realize the convenient construction and ensure the quality of structure,retarding mortar was prepared,which can meet the requirements of bonded post-tensioned prestressed concrete.Tests on crack resistance and crack closing of 21 retard-bonded partially prestressed concrete(PPC) beams were carried out,and the cracking strength and crack closing strength under static loading were obtained.The S-N curve of flexural fatigue cracking under constant-amplitude fatigue loading was analyzed.It is recommended tha...