超长混凝土框架结构裂缝控制措施

Measures on Crack Control of Super-long Concrete Frame Structure

超长混凝土框架结构裂缝控制的关键是控制温度应力。结构所处的内外温差及混凝土收缩所产生的变形,结构受到的约束及混凝土抗拉强度和混凝土的极限拉应变是影响温度应力的主要因素。温差越高和混凝土收缩产生的变形越大,受到的约束越大,产生的温度应力就越大,混凝土越易开裂。留设后浇带以及掺加膨胀剂可以减小混凝土收缩变形,设置橡胶支座可以减小结构约束,降低温度应力,施加预应力可以有效控制温度收缩裂缝。

The key of super-long concrete frame structure is to control temperature stresses. The main factors are temperature difference between inside and outside, concrete shrinkage, restriction, tensional strength and ultimate tensile strain. The stronger the restriction, temperature difference and shrinkage is the bigger will the temperature stresses. The concrete is apt to crack. Setting post-cast-strip and mixing expansile agent decrease shrinkage. Setting gliding supports decrease restriction and temperature stresses falls. Applying the prestress controls crack effectively.