钢筋混凝土地道桥施工裂缝的理论分析及预防措施

THEORETICAL ANALYSIS AND PREVENTIVE MEASURES ON CRACK IN CONSTRUCTION OF REINFORCED CONCRETE UNDERPASS BRIDGE

钢筋混凝土地道桥在施工完毕后由于混凝土早期收缩和水化热引起的内外温差的同时作用,经常会出现边墙竖向的施工裂缝。为探讨其产生的原因及预防措施,文中提出了考虑变形差引起的力学反应的理论计算方法,并进行了理论计算公式的推导和计算分析,同时给出了按混凝土名义拉应力估算裂缝宽度的计算公式。进一步讨论了温差及分层施工方法的影响。提出的结论和施工裂缝预防措施能对地道桥的设计和施工有所帮助。

Vertical construction crack often appear on the side wall of reinforced concrete underpass bridge due to the simultaneous effect of early shrinkage and temperature difference between inside and outside caused by hydration heat of concrete after the construction.,theoretical calculation method considering mechanical reaction caused by deformation difference was proposed in this paper to explore the causes and preventive measures.Theoretical calculation formula was deduced and analyzed,calculation formula of crack width estimated by nominal tensile stress of concrete was given as well.The influence of temperature difference and layered construction method were further discussed.The conclusions and preventive measures of construction crack can contribute to the design and construction of underground bridge.