Abstract:
To study the dynamic characteristics and vibration responses of discretely connected precast RC diaphragms (DCPCD) under human-induced excitation, six full-scale DCPCD specimens and one cast-in-place specimen were tested by hammer modal test and human-induced excitation test under bounce and jumping loads. The effects of plate seam and connector layout on DCPCD vibration characteristics were examined. The results show that the low-order vibration mode of DCPCD and cast-in-situ floor was basically the same, but the natural frequency of DCPCD was slightly lower. The DCPCD had the same vibration transmission mechanism as the cast-in-situ floor. The vibration response of DCPCD was slightly larger than that of the cast-in-situ floor under the same excitation. The peak acceleration value of the cast-in-situ floor appeared at the edge of the mid-span, and the peak acceleration of DCPCD appeared at the edge of the slab joint near the mid-span. The natural frequency of DCPCD increased with the increase of the slab joint connectors and with the decrease of the slab joint connections, where the effect of the connector on the frequency was greater than that of the slab joint connection. Methods for calculating the vertical natural frequency and acceleration of the DCPCD in the orthogonal slab laying directions with two pairs of sides simply supported were proposed. The accuracy of the proposed methods was verified by the experimental results.