克服典型病害的新型预应力混凝土空心板梁设计

提出了一种新型预应力混凝土空心板梁结构形式。采用匹配预制，界面设置剪力键的方法解决铰缝问题；采用双向预应力筋布置，保证桥梁纵向受力的同时，也防止了梁体纵向裂缝的出现，并保证匹配界面存在压应力。同时，采用底板开孔的方法，减少预应力混凝土空心板梁内外的温差，采用顶板切槽式拉毛，保证顶面桥面铺装与预应力混凝土空心板梁的粘结作用。设计算例的有限元分析表明，匹配预制双向预应力开孔混凝土板梁的底板，纵桥向和横桥向压应力储备分别大于2.58 MPa和0.16 MPa，有效的防止了底板纵向裂缝和铰缝病害的产生。

A new type of prestressed concrete hollow girder design for overcoming the typical diseases

This paper proposes a new type of prestressed concrete hollow girder based on the summaries of the current studies on longitudinal cracks and hinge cracks. The match prefabricated method is used with shear key at interface to solve the problem of hingle cracks, and the two-way prestressing strand techniques are used to assure the longitudinal load-bearing capacity and to prevent the emergence of longitudinal cracks because of pressure existing at the match interface. In order to reduce the temperature difference between the internal and external of the prestressed concrete hollow girder, drilling holes are carried out at the bottom slab of girder every distance. To ensure the adhesive effect between the girder and deck pavement, we designed grooves at the top slab of girders. The finite element analysis results of a design example show that the pressure stress of bottom slab of girder is about 2.58 MPa and 0.16 MPa, which are effective to avoid the appearance of longitudinal cracks and hinge cracks.