无屈服台阶钢筋混凝土受弯构件的强度计算及可靠度设计水平的概率分析

本文通过102根矩形构件的试验,分析了受弯构件的破坏形态及其承载能力的规律;论证了施加预应力对受弯构件正截面强度的影响;揭示了无屈服台阶钢筋在构件内的工作特性;指出了现行规范在正截面强度计算公式中存在的问题,与此同时在试验分析的基础上,提出了以静力平衡与变形协调条件为基础的计算公式。本文计算公式物理概念明确,适用性强,通过国内218根试验构件的验证,符合程度十分良好,与现行规范计算公式相比,这种方法更为合理,且可取得一定的经济效果。 此外,本文利用概率法对受弯构件可靠度的设计水平进行了校准,并对基本安全系数的合理取值进行了探讨。分析表明,按本文提出的方法进行设计,在不同钢种构件之间、同一钢种而不同配筋率的构件之间,均可获得较为一致的可靠指标。

Strength of Reinforced Concrete Flexural Members with Steel without Yield Point and the Reliability of Design by the Probability-Based Procedure

Through the tests of 102 rectangular section reinforced and pre-stressed concrete members subjected to bending, the rule of bearing capacity and failure modes of such members, the effects of prestress on the strength of normal sections and the working characteristics of high tensile steel in the members are presented. Computing formulas based on static equilibrium of forces and compatibility of deformation are proposed. The computation results and those from 218 test members show satisfactory agreement. As compared with the formulas in current code, the method presented in this paper is more rational and acquires economical effectIn addition, the realibility of the design of the above mentioned flexural members are calibrated by the probability-based procedure and values of primary safety factors are also discussed. As shown in this paper, by the use of proposed formulas for members either reinforced with different type of bars or members with varied steel ratio of same reinforcing bars, identical reliability index can be obtained relatively.