Seismic analysis of reinforcement of bottom frame-upper masonry structures under mainshock-rockfall-aftershock

The bottom frame-top masonry structure is most prevalent architectural form in mountainous towns and townships. This paper investigates disaster prevention of such structures under a three-dimensional sequence of mainshocks and aftershocks, incorporating disaster resistance performance scenario of “post- mainshocks − rockfall impact − subsequent aftershock effects”. It focuses on revealing the mechanism and effectiveness of reinforcement by adding seismic walls. The results indicate the following, the addition of seismic walls enhances structural rigidity. By altering the force transmission path, both rockfall impact loads and seismic actions can be dispersed to the seismic walls, thereby significantly mitigating the damage concentration effect on frame columns. Under mainshock effects with Peak Ground Acceleration (PGA) values of 0.1 g, 0.2 g, and 0.4 g, maximum inter-story drift ratio in the X, Y, and Z directions were reduced as follows: 82.8%, 64.8%, and 85.6% for PGA = 0.1 g; 60.1%, 80.6%, and 45.5% for PGA = 0.2 g; and 55.9%, 78.9%, and 57.2% for PGA = 0.4 g.