Torsional Strength of Precast Prestressed Concrete Members with Segmental Joint

由后张拼装的混凝土构件组成的预制预应力混凝土构件，在受扭或受扭与剪切和弯曲相结合的节段节点中存在弱点。本文着重研究了弹塑性区节段节点预制预应力混凝土构件的抗扭强度，并由此讨论了以下几点：(1)配筋量、预应力程度和节段节点表面状况对开裂后区域抗扭刚度的影响；(2)有无节段节点与混凝土粘结，在节段节点上布置非张拉筋的影响。在试验和理论研究的基础上，主要得出以下结论：(1)预应力对构件后开裂区扭转刚度和节点极限滑移的影响较大，为使单体预制混凝土构件的性能达到同等水平，节段构件的预应力应大于30kgf/cm2，筋-混凝土粘结强度应大于30kgf/cm2。(2)在节段节点上布置带粘结的非张拉预应力筋，对提高节段节点预制预应力混凝土构件的极限抗扭性能非常有用。

Precast prestressed concrete members which are made up of concrete elements assembled by post-tensioning have a weak point in a segmental joint under torsion or torsion in combination with shear and bending. This report focuses the torsional strength of precast prestressed concrete members with segmental joint in elasto-plastic regions, and thereby discusses on following points(1)the effects of the amount of reinforcement, the degree of prestress and the surface condition of segmental joint on torsional rigidity in post-cracking region,(2)the effects of the arrangement of non-tensioning tendon across the joint with or without the bond between tendons and concrete. On the basis of this experimental and theoretical investigation, the following conclusions are mainly drawn:(1)The effect of prestressing on torsional rigidity of the member in post-cracking region and slippage at joint in ultimate stage is large, and it is necessary to give to a segmental member the prestress of more than 30kgf/cm2 and the bond between tendon and concrete for an equal level of the behavior of mono-precast concrete member.(2) The arrangement of non-tensioning tendons to segmental joint with the bond is very useful to improve an ultimate torsional properties of precast prestressed concrete members with a segmental joint.