施工期现浇钢筋混凝土楼板裂缝鉴定与承载性能分析

CRACK IDENTIFICAITON AND BEARING CAPACITY ANALYSIS OF CAST-IN-PLACE REINFORCED CONCRETE FLOOR DURING THE CONSTRUCTION PERIOD

为了研究施工期现浇钢筋混凝土楼板裂缝产生的原因及承载性能,对混凝土构件进行现场检测、静载试验,结合数值模拟对检测数据进行比对分析。结果表明,拆模过程中楼板板底温、湿度的突变是导致板底裂缝剧增的原因之一;在一定温度范围内,楼板裂缝宽度随温度上升而增大,呈抛物线特征;楼板裂缝是因施工期温度变化、养护不到位等原因产生的非结构性裂缝;静载试验加载、卸载过程中楼板挠度与对应荷载呈线性关系,楼板未出现明显塑性变形且处于弹性状态,满足正常使用要求;非结构性裂缝对构件的承载力影响较小。通过现场检测、数据分析及裂缝产生原因的判定方法,可为今后类似项目提供工程经验。

In order to study the causes and bearing performance of cracks in cast-in-place reinforced concrete floor slabs during the construction period,the on-site inspection and static load tests were conducted on concrete components,and numerical simulation was combined to compare and analyze the inspection data.The results indicate that the sudden change in temperature and humidity at the bottom of the floor slab during the demoulding process is one of the reasons for the sharp increase in cracks at the bottom of the slab;Within a certain temperature range,the width of the floor cracks increases with the temperature and exhibits a parabolic characteristic;Floor cracks are non structural cracks caused by temperature changes during construction and inadequate maintenance;During the loading and unloading process of the static load test,there is a linear relationship between the deflection of the floor slab and the corresponding load.The floor slab does not show significant plastic deformation and is in an elastic state,it meets the requirements for normal use;Non structural cracks have a relatively small impact on the bearing capacity of components.The methods of on-site inspection,data analysis,and determination of the causes of cracks can provide engineering experience for similar projects in the future.