国产高强钢高温动态弹性模量试验研究

EXPERIMENTAL RESEARCH ON DYNAMIC ELASTIC MODULUS OF DOMESTIC HIGH STRENGTH STEEL AT ELEVATED TEMPERATURES

高温下弹性模量的降低将影响钢结构的承载能力和刚度,因而精确得到高温弹性模量值对于指导钢结构抗火设计、评估火灾下钢建筑性能具有重要意义。我国关于钢材高温弹性模量的现行规范为基于普通钢试验结果制定,相关研究也主要针对普通钢,国产高强钢研究的缺乏制约其在建筑工程中的应用。因此采用悬丝耦合弯曲共振法对国产高强钢Q550、Q690、Q890进行试验研究,得到3种不同强度等级钢材在20~800℃内的高温动态弹性模量值,并将所得折减系数结果与国内外相关规范和研究成果做对比。试验表明:不同强度等级高强钢的动态弹性模量折减系数随着温度升高有相似的变化规律,且明显比静态试验随温度变化的结果和相关规范值高。依据试验结果建立了国产高强钢高温动态弹性模量模型。

The deterioration of elastic modulus at elevated temperatures affects the load-bearing and stiffness of steel structures significantly.Therefore,it is important to obtain the precise elastic modulus at high temperatures,for conducting fire resistance design and evaluating the performance of steel structures.The current China national codes for high temperature elastic modulus were developed based on the results of mild steel.The previous researches also mainly focused on mild steel,so the lack of research on domestic high strength steel seriously restricted their application in building structures.An experimental study was carried out to investigate the high temperature dynamic elastic modulus of domestic high strength Q550,Q690,Q890 steel by suspended coupling bending resonance method.The tests were conducted at various temperatures ranged 20 ~ 800 ℃.The paper compared the reduction factors of elastic modulus obtained from the tests with different codes and available researches both domestically and internationally.The results showed that the dynamic elastic modulus reduction coefficients of domestic high strength steels were similar with increasing temperature.Besides,the dynamic elastic modulus are obviously higher than the static results and current codes.According to the test results,the predictive equation of elevated-temperature dynamic elastic modulus of domestic high strength steel was proposed in the paper.