# A Study on the Seismic Performance of Steel H-Column and T-Beam-Bolted Joints
## 1 Introduction  
Among the existing beam-column joints in steel-frame structures, high-strength bolted joints exhibit superior deformation capabilities and stiffness comparable to that of fully welded joints. Refs. [1, 2] investigated steel tubular column-I-beam joints and found that both end-plate (bolted) and short-beam (welded) connections met seismic requirements, confirming comparable stiffness and deformation capacities between bolted and welded systems. In steel-frame structures, the steel-frame system is composed of square steel-pipe columns and H-type steel beams featuring high bearing capacity, excellent seismic performance, and relatively high economic benefits. These advantages have led to the increasingly widespread application of square steel-pipe column H-type steel-beam connections in engineering projects. In order to solve the brittleness problem of traditional-welded joints, [PERSON] et al. [3] proposed a blind bolt-connection technology, which dissipates energy through bolt slip and plastic deformation of the connecting plate, and its design allows the joints to maintain stable bearing capacity at \(\pm\)0.05 rad displacement. In recent years, domestic and international scholars have conducted extensive experimental, finite-element analysis, and theoretical research on different joint forms, achieving many research outcomes. [PERSON] [4; 5; 6] carried out experimental research on the spatial and planar joints connected by T-shaped beam-column components. The results demonstrate that the mechanical properties of spatial joints are inferior to those of planar joints, and the spatial coupling effect cannot be overlooked in practical engineering applications. The bearing capacity and rotational stiffness increase as the stiffness of the T-shaped components rises. The expressions for the tensile capacity and stiffness of the T-shaped components are derived using the component method. The application of semi-rigid joints in steel structures has gradually increased. [PERSON] et al. [7] found, through a quasi-static test, that the T-shaped steel tubular column H-shaped steel-beam joint has good energy dissipation capacity, and its plastic hinges mainly appear at the joint between the T-shaped steel web and the flange, and the equivalent viscous damping coefficient reaches 0.16-0.19. [PERSON] et al. [8; 9; 10] conducted a monotone static loading test on three full-size cold-formed square steel tubular column joints connected by unidirectional bolts with the extended end plates of H-type steel beams and studied the performance of the joints through parametric analysis. The results show that the stiffness and bearing capacity of the joint can be effectively improved by increasing the thickness of the column wall. When the thickness of the column wall exceeds 14 mm, the shear and tensile failure of the bolt occurs. [PERSON] et al. [11] designed a single-bolt-shaped connection node and carried out low-cycle reciprocating load tests on five single-bolt T-shaped connection nodes and one core-bolt T-shaped connection node. The results demonstrate that under cyclic loads, the joints of single-bolt-shaped components work in an alternating tension compression mode, and the tension bolts can achieve strong anchoring strength. The joints of single bolt T-shaped components can transfer forces reliably in the composite concrete-filled steel tube structure, and the structural integrity is satisfactory. [PERSON] et al. [2] investigated the steel tubular column-I-beam joints. They employed finite-element modeling to analyze the mechanical properties of end-plate joints and short-beam joints under cyclic loads. The results indicated that both types of joints could meet the seismic requirements. The short-beam connection effectively addresses the issue of being unable to access the interior of the box column to tighten the bolts. [PERSON] et al.