摘要
试验表明,钢筋混凝土简支厚板在中置集中荷载作用下的双向弯曲很明显。特别是当板的宽跨比较大、集中荷载的面积较小时,其双向作用更为明显。按常规设计,往往只计算Mx方向配筋,而My方向则按构造配筋。因此,工程上经常出现沿板跨度方向的裂缝,即板的纵缝,并且由于My方向配筋过少,板纵向裂缝的宽度远大于横向裂缝的宽度。本文首先对简支厚板在集中荷载下的裂缝形态进行了试验研究,然后,将厚壳单元引入板的有限元分析,进而讨论了钢筋混凝土双向厚板的剪跨比、厚宽比、宽跨比对板横纵向弯矩比值的影响,提出了适用于控制不同厚度的厚板纵缝的纵向弯矩比简化计算公式,为设计提供参考。
The experiment shows that the biaxial bending of reinforced concrete thick slabs with two free edges and two clamped edges under concentrated loads acting on the center of slab is obvious, especially on the slabs with large width to length ratio or small loading areas. According to the conventional design method, the longitudinal reinforcement is calculated according to Mx, but the transverse reinforcement is determined by the minimum ratio of reinforcement. Therefore, the phenomenon of cracking extended along the span of slab （longitudinal crack of slab） is commonly happened in construction and the width of crack along longitudinal direction is far greater than that along transverse direction which is caused by the less transverse reinforcement. In the paper, the experimental research on the cracking trend of the thick slab with simply supports under concentrated loads is carried out first. Second, an eightnode isoparametric thick plate element for the slab is proposed and the FEM analysis is performed. Third, by parameter study, the relationships between the ratio of My to Mx, shear span ratio, the ratio of thickness to width, the ratio of width to length are studied. For engincering design, an effective formula for calculating longitudinal moment is derived which is convenient for the analysis of thick plate with various thickness.
出处
《四川建筑科学研究》
北大核心
2006年第2期6-8,共3页
Sichuan Building Science
关键词
钢筋混凝土
简支厚板
集中荷载
纵向裂缝
厚壳单元
有限元
纵向弯矩
reinforced concrete
thick slab with simply support
concentrated load
longitudinal crack
thick plate element
FEM
longitudinal moment
