二次预应力超薄梁徐变效应试验研究

预应力混凝土超薄结构应用于多层立交中将产生巨大的经济和景观效益,但在超薄梁上施加预应力将导致反拱过大和徐变长期反拱不断发展。针对为解决此问题提出的二次预应力新型结构,推导了二次预应力结构任意时刻徐变和徐变内力的计算公式;并且通过与常规预应力梁的对比试验研究,证明了二次预应力能大大改善预应力混凝土梁的变形性能。二次预应力超薄结构在控制变形中的优势,使其有着广阔的应用前景。

Experimental Research on Creep Effects of Twice Prestressed Low Height Beam

The application of prestressed concrete low height beam in viaduct and interchange can bring huge economic benefits.But the camber of low height beam is often too large due to the large additional stress of prestressing and will constantly increase due to creep.To solve these problems,the conception of new typed bridge of twice prestress has been put forward in this work.This paper derived the solutions of creep strain and internal force due to creep in twice prestressed beam with respect to time t.Meanwhile,through the comparative analysis and experimental research between this new structure and general structure using post-tensioning tendons,it was observed that the application of twice prestress to low height beam can improve the mechanical and deformational performance of prestressed low height beam in the construction process and for long-term use.The advantages of twice prestressed low height beam in controlling deformation will make twice prestress have more applications in the future.