火灾后钢筋混凝土异形柱结构损伤评估的基础研究

异形柱结构的梁、柱和节点区由于表面积较大、肢厚较薄等原因，其火灾后损伤程度通常比非异形柱结构的更为严重，但目前有关火灾后混凝土异形柱结构损伤评估方面的研究成果较少。通过试验和数值模拟，对受火后混凝土异形柱的受压、受剪和抗震性能，受火后截面高宽比较大的混凝土简支T形梁和连续T形梁的受弯、受剪、内力分布等承载性能，受火后异形柱结构中带正交梁和楼板翼缘的中节点和边节点的抗震性能，受火后单层异形柱空间框架的抗震性能等进行较系统的研究，并提出其灾后承载力的定量评定方法；提出“受火时间比”这一新的参数指标，建立能定量考察高温下持荷对灾后柱式构件受压性能影响的试验方法和数值模拟方法；建立异形柱、压区高温梁、梁柱节点受火后受剪性能的力学分析模型，揭示灾后受剪的方向异性对其受剪承载力的影响规律；阐明异形柱空间框架中构件的火灾损伤特性和规律。项目研究成果可为火灾后混凝土异形柱结构的损伤评定和抗震修复奠定基础。

The beam, column and beam-column joint in reinforced concrete structure with special-shaped column after fire, due to larger surface area and thinner thickness, are generally damaged more serious than those in structure with non-special-shaped column. Up to now, researches on damage assessment of reinforced concrete structure with special-shaped column after fire are few. Through the experiments and numerical simulation, the compression performance, the shear performance and the seismic performance of concrete special-shaped column, will be studied systematically. Then, the bending performance, shear performance and internal force distribution of the concrete simple-supported T-shaped beam and continuous T-shaped beam with a high depth-to-width ratio of cross-section after fire will be carried out. Subsequently, the seismic performance of beam-column interior-joint and exterior joint with slab and orthogonal beam in the special-shaped column structure after fire will be conducted. And the seismic performance of single layer space frame with special-shaped column will be further performed. The quantitative evaluation method for the residual capacity of the special-shaped column structure will also be put forward. A new parameter index named "fire exposure time ratio" is proposed, and the experimental and numerical methods to quantitatively determine the post-fire compression performance influenced by the sustained axial load under high temperature will be constructed. The mechanical analysis model for the shear behavior of the special-shaped column, the concrete beam with compression zone directly exposed to fire and the beam-column joints after fire will be established. The influence laws of the directional anisotropy on shear capacity after fire will also be revealed. The fire damage regularity and characteristics of the members in frame with special-shaped column will be further clarified. The project aims to lay a foundation for damage assessment and seismic strengthening of the concrete structure with special-shaped column after fire.