Experimental and simulation studies on the mechanical performance of concrete T-Girder bridge strengthened with K-Brace composite trusses

In this paper, a new transverse strengthening method was proposed for T-girder bridges with K-brace composite trusses. A series of experiments and simulations were conducted to study the strengthening effects under four different loading conditions, including non-eccentric loading, transverse eccentric loading, longitudinal eccentric loading, and bidirectional eccentric loading modes. Altogether four groups of specimens were fabricated and studied. Each group consisted of a control specimen and a strengthened one. Furthermore, the concrete plastic damage model was used to simulate the mechanical behaviors of the specimens. The results showed that such a strengthening method could significantly upgrade the mechanical behaviors of the T-girder bridge specimens, especially the local deformation and crack propagation manner of the T-girder. Compared with the control specimen, the deflection of concrete T-girder bridge specimen strengthened with the K-brace composite trusses was significantly decreased, with a maximum reduction of 38.6% under the prescribed load. Moreover, the Kbrace composite trusses can markedly better the load distribution and improve the failure modes of the specimens, where the crack widths decreased even by 44.0%. They distributed along the beam more evenly. So, it provides a new method to strengthen and upgrade the mechanical properties of T-girder bridges.