【摘要】 通过体外预应力组合梁的承载力试验,研究了负弯矩作用下体外预应力组合梁的开裂和极限承载力。研究结果表明:对负弯矩区组合梁施加体外预应力后,可有效提高截面的开裂弯矩。负弯矩作用下体外预应力组合梁的预应力增量很小,可忽略。一般情况下,对负弯矩截面施加体外预应力,不会提高截面的屈服承载弯矩。负弯矩作用下体外预应力组合梁的极限承载力受失稳控制。把预应力作用作为等效荷载,探讨组合梁失稳承载力的计算方法,采用BS5400:Part3方法计算了预应力组合梁的失稳临界弯矩。更多还原

【Abstract】 Tests have been carried out to study the cracking behavior and the load carrying capacity of steel-concrete composite beams prestressed with external tendons under negative moment.It is found that by prestressing the composite beams with external tendons,the cracking load of the beams can be effectively increased.The increase of tendon force of the composite beams under negative bending is small and negligible.Normally,prestressing of the composite beams under negative bending can hardly increase the yield moment of the composite section,and the load carrying capacity is goverred by buckling of the web in distortion and the flange in compression.The method to evaluate buckling resistance of the composite beams is discussed,and based on the BS5400 method,the buckling resistances of the test beams are assessed,treating the prestress as equivalent load.更多还原