Experimental Study On Seismic Behavior Of Pre-cast Reinforced Concrete Shear Walls

Industrialization is the direction for construction of the residential buildings. The assembled pre-cast shear wall structural system is suitable for Chinese condition. The connection between the adjacent shear walls is the key issue for the integrity and the anti-seismic capacity of the assembled pre-cast shear wall structural system. On the background of building D1# and building D8# of Vanke Company, quasi-static tests of eight pre-cast shear wall specimens and one cast-in-situ shear wall specimen with shear span ratio of 2.25 were carried out. Among the eight pre-cast wall specimens, the vertical reinforcements of four specimens were directly spliced by grout sleeves, for the other four specimens the vertical reinforcements were grouted in holes and spliced indirectly. The side face of the pre-cast wall specimens was treated with two methods to connect the cast-in-place concrete, one was shear key and the other was rough face.The test results indicate that the failure mode of the pre-cast wall specimens is about the same as that of the cast-in-situ wall specimen, i.e., tensile yield of vertical reinforcements and compressive failure of concrete. Except one specimen with indirectly spliced vertical reinforcements the failure of concrete was at the bottom of the wall, for that specimen the failure of concrete was just above the top of the holes. The crack pattern for the pre-cast walls and the cast-in-situ wall is different: for the cast-in-situ wall the main crack is horizontal cracks at the bottom section of the wall and in the range of 500mm height from the bottom section above, while for the pre-cast walls the main crack is horizontal cracks at the bottom section of the wall and above the top of the sleeves or holes. The stresses of the vertical reinforcements can be transferred effectively by the grout sleeves and by indirect splicing. Both shear key and rough face can connect the pre-cast wall with cast-in-site concrete to be unite, the integrity behavior of rough face is better than shear keys. The peak load-carrying capacity of the pre-cast wall specimens was 1.13 to 1.4 times the current code formula value. With the same axial compression ratio, the crack stiffness of the pre-cast walls was a little lower than that of the cast-in-situ wall, and the yield stiffness was almost the same. The ultimate drift ratio of the pre-cast walls were 1/36~1/59, larger than the story drift ratio demand for the shear wall structure under the maximum earthquake. The top lateral force-displacement hysteretic loops of the pre-cast walls were plump; the energy dissipation capacity was a little lower than that of the cast-in place wall.Furthermore, non-linear finite element analysis (FEA) of nine specimens was performed based on the general FEA program MSC.Marc. The predicted lateral force-displacement curve had good agreement with the measured skeleton curve of hysteretic loops. It is very helpful for the further study on the seismic behavior of the pre-cast RC shear walls.At last, it is proposed that the pre-cast shear wall with vertical reinforcements spliced by grout sleeves can be regarded as the cast-in-situ shear wall in practical design.