Suggestions for a Collapse-Resistant Design for Frame–Masonry Hybrid Buildings Based on the Concept of Balancing Seismic Shear Forces

Abstract

Frame–masonry hybrid structures, though economically practical and widespread in rural China, face significant collapse risks during earthquakes due to shear imbalances from a component mismatch. A severe case was No. 7, Group 1, Detuo Town, after the 2022 Luding earthquake, where damage was concentrated on the ground floor. Numerical modeling revealed that the axis Ⓒ perforated wall, bearing 78% of the seismic shear due to its stiffness, suffered shear failure from geometric and structural factors, triggering a shear concentration–brittle failure chain reaction, pushing the building to near collapse. Meanwhile, the axis Ⓐ frame column, only sustaining 12% shear, sustained minor damage. Based on this typical seismic damage, this study proposes a collapse-resistant design using the deformation saturation theory to achieve balanced shear distribution by adjusting frame column sections. The results showed that compared to the prototype model, the collapse-resistant model (RE) under PGA = 0.4 g saw maximum displacement drop from 16.66 mm to 5.42 mm, which was reduced by 67.5%, the shear share of axis Ⓐ rose from 18% to 45%, the shear force of axis Ⓒ decreased from 70% to 46%, the shear ratio changed from 1:4 to 1:1, and maximum component damage was at 75% of the performance point, indicating significantly enhanced collapse resistance. These findings highlight the importance of balanced seismic shear distribution in preventing shear concentration and brittle failure, validate the deformation saturation theory, and offer a theoretical basis and design reference for the seismic reinforcement of similar hybrid structures.