HWFC叠合加固钢筋混凝土工形梁试验研究

针对现有混凝土连续梁桥(含连续刚构)在承受负弯矩作用下的开裂病害以及渗水引起的钢筋锈蚀问题,其中一种加固方法是在梁顶面铺设含密间距带肋钢筋网片的高掺量混杂钢纤维混凝土层。采用该理念,对负弯矩作用下采用该加固方法的混凝土工形梁进行了相关试验研究,结果显示加固后的工形梁较原无损工形梁的开裂弯矩提升幅度达到44.94%～131.91%,且同级荷载作用下裂缝宽度减小约30%～50%,表明该方法能够有效提高构件顶面的抗裂能力和阻裂能力。以HWFC复合层初始裂缝出现时的弯矩为加固后的开裂弯矩,推导了加固后工形梁的开裂弯矩计算式,并参照普通钢筋混凝土构件对于开裂弯矩的计算方法给出了按现行规范形式的开裂弯矩计算式。

Experimental research on concrete I beam reinforced by HWFC composite layer

Aiming at the cracking disease and steel-bar corrosion problems caused by leakage for existing concrete continuous beam bridges (including continuous rigid frame bridges) under negative moment,a new method that laying high content hybrid steel fiber reinforced concrete composite layer with fine-pitch ribbed steel-bar web has been proposed to reinforce the top slab of the beam.This paper conducted experimental studies of concrete I beam reinforced by HWFC composite layer under the negative moment.Compared with the original nondestructive beam,the cracking moments of the reinforced beams have been improved by 44.94%~131.91%,and the widths of cracks have been reduced by 30%~50%.The results show that HWFC composite layer can effectively improve the crack resistance of the top surface.Take the moment when the initial crack occurs as the cracking moment of HWFC composite layer,the calculation formula of cracking moment of reinforced beam was derived.