Traditional Chinese wood residences consist of timber frames with masonry infill walls or other types of infill, representing valuable heritage. A field investigation of traditional village dwellings in northern China consisting of timber frames with mud and stone infill walls was conducted. Their construction characteristics are reported, and static cyclic tests were performed on two full-size wood-stone hybrid walls with different configurations (exterior transverse wall and internal transverse wall) and no openings (doors or windows). Their failure mechanics and seismic capacity, i.e., the strength, stiffness, ductility, and energy dissipation, were investigated. The results are compared with a previous experimental study of two full-size timber frames with the same traditional structure but no infill to determine the effect of the mud and stone infill on the lateral resistance. The experimental results indicate that the stone infill has a critical influence on the lateral performance of traditional village buildings, resulting in a high lateral stiffness, high strength (>20 kN), and a high ductility ratio (>10). An increase in the vertical load leads to an increase in the lateral resistance of the timber frame with infill walls, larger for the internal transverse wall than the external gable wall. The incompatibility of the deformation between the timber frame and stone infill is the main failure reason, resulting in falling stones and collapse with undamaged timber frames. Suggestions are provided for the protection and repair of traditional wood residences in northern China.
The long-term deformation of a 17.5 m deep excavation constructed with the bottom-up technique in silty clay in Xi’an was monitored in this study. The retaining wall was built with one or two rows of contiguous bored concrete piles and tie-back prestressing tendons. The monitoring of settlement and lateral deflection at the top of the retaining structure, and the settlement of the ground surface and of the adjacent building lasted for more than 4 years. After the final depth was reached, the excavation was surveyed for more than 3.1 years. It was observed that the deformation of the excavation increased with the increase in the excavation depth, and a significant increase in displacement was recorded after the excavation reached the final depth. The averaged time-dependent rates of the deflection of the retaining wall, and the settlement of the ground surface and of the adjacent building when the excavation remained partially unfilled were around 0.23–0.25 mm/month in this study. The time-dependent behavior of the excavation could lead to excessive deformation and cause severe safety risks to the retaining system. The recorded data, together with a comparison with cases reported in the open literature, are presented in this paper.
In this study, unreinforced masonry (URM) walls constructed from concrete blocks and clay bricks were strengthened using horizontally and vertically oriented glass fiber-reinforced polymer (GFRP) grid strips bonded with sprayed polyurea. The walls were subjected to diagonal compression loading until failure. The results demonstrated a significant improvement in both the shear capacity and pseudo-ductility of the strengthened URM walls compared to their unstrengthened counterparts. The primary conclusions drawn from this research are as follows: (1) the maximum strain in the vertical GFRP strips increased with the higher axial stiffness of the strips; (2) the discrete vertical strips contributed substantially to enhancing the shear capacity and pseudo-ductility of the URM walls; (3) increasing the axial stiffness of the vertical strips can alter the failure mode of the walls, shifting it from joint failure to tension or compression failure of the blocks or bricks; (4) a reduction factor is necessary to account for the potential asymmetrical performance of double-sided strengthening schemes applied to URM walls. The experimental program was reported in a previous publication and additional information is presented in this paper.