摘要
混凝土水化热是单箱多室混凝土箱梁产生早期裂缝的主要因素之一,而目前对于单箱多室混凝土箱梁水化热研究较少。以佛山市奇龙大桥边跨单箱多室混凝土箱梁作为研究对象,通过各重要部位布置的测点对浇筑后的水化热温度场进行了长达14 d的连续测试,明确了箱梁不同部位水化热的发展规律。基于ANSYS有限元软件对该混凝土箱梁温度场进行了仿真分析,分析结果与实测值吻合;基于混凝土材料的力学性能的发展规律,对水化热温度场所致的结构应力场进行了分析,得到了混凝土箱梁各控制点的应力时程曲线及箱梁腹板内外温差的控制限制。结果表明:对于所研究的混凝土箱梁而言,外腹板的主拉应力最大,其值为2.14 MPa,小于对应时刻的抗拉强度值2.53 MPa,但应力长时间处于较高的水平,因此腹板内外温差应控制在30℃以内。根据实测与分析结果,提出了单箱多室箱梁开裂控制的混凝土配合比设计及养护建议。
Concrete hydration heat is one of the critical factors for early crack of concrete box girder in single-box with multi-cells,however,few studies have been reported on this problem during the decades. Based on the concrete box girder in the side span of Qilong Bridge,the hydration heat temperature field in the box girder was explored via a continual measurement of the concrete girder for 14 days. The results from ANSYS program models also showed good agreements with test results,and the structural stress caused by concrete hydration was also discussed on the basis of the development of concrete mechanical properties. The time travel curve for concrete stress in different sections of the girder,in addition to the control limitation for the temperature difference between the inner and outer surfaces of the box girder were achieved. The results indicated that the maximum stress in out concrete web of box girder was 2. 14 MPa,and it was lower that than the concrete strength of 2. 53 MPa. The temperature difference between the out and inner web was suggested to be under 30 ℃. Based on computing and test results,suggestions for the optimizations of concrete mixture were control early concrete working were proposed.
出处
《公路工程》
北大核心
2017年第6期254-260,共7页
Highway Engineering
关键词
单箱多室混凝土箱梁
水化热
温度场
有限元分析
box girder in single -box multi -cell
hydration heat
temperature field
element analysis
