体外预应力梁和体外索共同工作规律的研究

Study on Rule of Co-acting between Externally Prestressed Concrete Beam and External Tendons

体外预应力梁在承受荷载时,体外预应力仅通过转向块和锚固点作用在梁体上,由于体外索和混凝土梁变形不一致,存在着应力滞后现象,导致体外索和钢筋混凝土梁之间协调工作能力的大小不等。本文结合广西科学基金项目"体外预应力加固梁的试验",通过分析转向块的设置、体外索的形状、荷载类型、有效张拉预应力、体内非预应力钢筋的配筋率、偏心距、应力增量和混凝土强度等几种影响因素,发现体外索和钢筋混凝土梁两者共同工作的规律:梁的刚度是决定体外索和钢筋混凝土梁两者共同工作的主要因素。本文结论对体外预应力基础理论发展有一定的借鉴意义。

When the externally prestressed beam is loaded, the external prestressing force acts on the beam through the deviator and anchored points. There exists the stress lag phenomenon caused by inconsistent deformation of the external tendons and beam, and this results in the unequal co-acting ability between the external tendons and beam. In combination with the Guangxi Natural Science Fund project ＂Experiment of strengthening beams with external prestressed tendons＂, influencing factors such as the setting of the deviator, shape of external tendons, loading pattern, effective stretching prestress force, reinforcement distribution rate of internal non-prestressing steel, eccentricity, stress increment and concrete strength are analyzed and the rule of co-acting between the externally prestressed reinforced concrete beam and external tendons is found;the beam stiffness is found the main factor of co-acting between the prestressed concrete beam and external tendons. This paper provides reference to development of the basis theory of external prestressing forces.