Abstract:In order to improve the seismic behavior of the reinforced concrete coupling beam with small span-to-depth ratio, the influences of matrix material and steel plate were considered. A new type of plate-fiber reinforced concrete composite double (PFRCCD) coupling beam was proposed. The failure process, failure mode, bearing capacity, deformation capacity and energy dissipation of the ordinary concrete double (OCD) coupling beam specimen, plate-reinforced composite double (PRCD) coupling beam specimen and PFRCCD coupling beam specimen were studied. The results showed that, the shear failure occurred in the OCD coupling beam specimen, the bending shear failure occurred in the PRCD coupling beam specimen, and the good ductility and bending failure occurred in the PFRCCD coupling beam specimen. After adding steel plate, the bearing capacity of the PRCD coupling beam specimen at the peak point was nearly 1.56 times higher than that of the OCD coupling beam specimen. The bearing capacity of the PRCD coupling beam specimen differed little from that of the PFRCCD coupling beam specimen at peak point. The existing of steel plate decreased the internal force damage caused by the opening of the double beam, and the addition of fiber had little influence on the increase of the bearing capacity of the composite double coupling beam. At the failure point, the cumulative energy dissipation of the PFRCCD coupling beam specimen were 5.26 and 2.20 times that of the OCD coupling beam specimen and the PRCD coupling beam specimen, respectively. Compared with the other two specimens, the PFRCCD coupling beam specimen exhibited better bearing capacity, deformation capacity and energy dissipation capacity. Until the final failure of specimen, the concrete of the PFRCCD coupling beam specimen remained intact, so as to reduce or even avoid concrete cracking damage and reduce post-earthquake repair costs. It provided a theoretical basis for the practical application of composite double coupling beam.