Fire performance of load bearing elements in steel buildings such as columns and frames has major importance for structural designers. This study aims to assess the elevated temperature effect on dynamic characteristics of steel columns and frames by conducting sequential heat transfer and modal analyses. A series of finite element analyses including heat transfer analysis aere performed on 62 different steel columns and frames. Three-hour part of ISO 834 fire curve is taken into consideration in the analysis. Modal analyses are conducted for the purpose of providing a more comprehensive image of dynamic characteristics in specific duration of elevated temperature. The presented study accommodates the effect of various steel profile types, cross-sectional dimensions and exposure durations on changes in dynamic characteristics. The outcomes of the performed parametric study revealed the decrease in natural frequencies with the temperature growth. The research has also shown the existence of a correlation between temperature variations and changes in mode shapes. The change in mode shapes depends on the profile type. Mode shapes do not change depending on the temperature in some profile types, while in some profile types they change after a certain temperature. The obtained results of the performed sequential analyses are presented in forms of tabulated data and approximate formulas. They can facilitate the damage detection process and contribute in required structural health monitoring measurements while enhance the accuracy of damage assessment for fire exposed steel structures.

对于钢结构建筑物（如柱和框架）中的承重元件，其防火性能对结构设计人员而言至关重要。这项研究旨在通过进行顺序传热和模态分析来评估高温对钢柱和框架动力特性的影响。一系列有限元分析，包括对62种不同的钢柱和框架进行的传热分析。分析中考虑了ISO 834防火曲线的三个小时部分。进行模态分析的目的是在特定的高温持续时间内提供更全面的动态特性图像。提出的研究适应了各种钢型材类型，横截面尺寸和暴露持续时间对动态特性变化的影响。进行的参数研究的结果表明，自然频率随着温度的升高而降低。研究还表明，温度变化与模式形状变化之间存在相关性。模式形状的变化取决于轮廓类型。在某些轮廓类型中，模式形状不会随温度而变化，而在某些轮廓类型中，它们会在特定温度后发生变化。进行的顺序分析的结果以列表数据和近似公式的形式表示。它们可以促进损坏检测过程，并有助于进行所需的结构健康监测测量，同时提高火灾暴露的钢结构的损坏评估的准确性。