摘要
在既有结构可靠性评定和结构健康监测中,梁挠度既是构件正常使用性能的直接体现,也能反映构件的安全状况。以构件安全性控制为目标,证明梁挠跨比与最大拉应变和挠跨比综合系数成正比,并用钢、木梁受弯性能试验文献中的数据对挠跨比综合系数进行了验证。混凝土楼板与钢梁的协同作用使其挠跨比受截面高度增大、截面中和轴高度变化、混凝土翼板与钢梁之间滑移及负弯矩区刚度变化的影响,综合影响系数为0.64~0.83。木楼板与木梁的协同作用对挠跨比的影响不大,但木材蠕变引起木梁长期挠度显著增长。建立了基于最大拉应变限值的梁挠度分级控制方法。与现行标准中的挠度限值进行了比较,结果表明:建议的挠度限值具有明确的安全性控制目标,并根据梁的具体受力特征变化而有显著不同,比现行标准的限值范围更宽、适应性更强且更精确,可供既有结构可靠性鉴定和结构健康监测参考。
In the reliability assessment and health monitoring of existing structures,beam deflection is not only a direct reflection of the normal service performance of structural members,but also a reflection of the safety status of structural members.Aiming at the safety control of structural members,this paper proved that the deflection to span ratio of beams is directly proportional to the maximum tensile strain and the comprehensive coefficient of deflection to span ratio.The comprehensive coefficient of the deflection-span ratio was validated using data from experimental references on the flexural performance of steel and timber beams.The synergistic effect of concrete floor slabs and steel beams affects the deflection to span ratio by increasing the height of the section,changing the height of the section neutral axis,sliding between the concrete wing slab and the steel beam,and changing the stiffness in negative moment area.The comprehensive influence coefficient is about 0.64~0.83.The synergistic effect of timber floors and timber beams has little effect on the deflection to span ratio,but wood creep causes a significant increase in the long-term deflection of timber beams.A beam deflection graded control method based on the maximum tensile strain limit was established.Compared with the deflection limit value in current standards,the results show that the deflection limits proposed in this paper has a clear safety control target,and is significantly different according to the change of the specific force characteristics of the beams.The range of the deflection limit is wider,more adaptable and more accurate than the current standard,and can be used as a reference for reliability identification and structural health monitoring of existing structures.
作者
蒋利学
张永群
白雪
王卓琳
JIANG Lixue;ZHANG Yongqun;BAI Xue;WANG Zhuolin(Shanghai Key Laboratory of Engineering Structure Safety,Shanghai Research Institute of Building Sciences Co.,Ltd.,Shanghai 200032,China)
出处
《结构工程师》
2024年第2期1-10,共10页
Structural Engineers
基金
国家重点研发计划(2017YFC0806100),上海市科学技术委员会科研计划项目(22DZ1203600)。
关键词
钢梁
木梁
安全性
挠度
限值
steel beam
timber beam
safety
deflection
limit value
