Narrow Results

This paper studies the subway-induced vibrations on two adjacent masonry structures in Shanghai with focus on the vibration level and frequency. The results show that: (1) the vibration levels of the two masonry structures in three directions are all higher during the peak traffic hours than the off-peak hours and are higher in the daytime than at night. In addition, they are higher at the mid-span of the floor than the wall-floor junctions and staircase. (2) The parameters of the numerical model were calibrated by the measured vibration response. The slab properties, room size, and other factors can affect the vibration response distribution. (3) The vertical vibrations in the rooms with precast slab are greater than those with cast-in-situ slab. The vertical vibrations at the ash seam between the precast slabs are amplified. In addition, the room depth has a small effect on the vibration intensity. The relationship between the room depth and the vibration intensity depends on the relative width and depth of the room. (4) The width of the room has a significant effect on the vertical vibration. The floor corner and surrounding wall constraint conditions greatly affect the vibration intensity.

In the paper, the dynamic control of structural vibrations in ancient constructions is considered. Since the constituent material of the structure exhibits poor tensile resistance, an effective performance of the algorithm requires the nonlinearity of the structure to be considered at the very first stage of the design of the control algorithm. Inclusion of the material nonlinearity of the structure into the design of the control mathematical rule presents a number of issues of high complexity either from the theoretical or computational aspects, which make the topic poorly treated in literature, in particular through full mathematical approaches. In the first part of this paper, one sets up a full model for analysis of the spatial masonry constructions with holonomic plasticity taken into account, and, in the second part, one formulates an algorithm aimed at mitigating the dynamic effects on the structure. The implementation of the control algorithm, the development of original calculus codes and the numerical investigations show the high potential of the proposed approach in significantly improving the performance of the structure.

A strong earthquake with a moment magnitude of $M_w=5$.9 according to the Disaster and Emergency Management Authority (AFAD) occurred at 04:08 local time on November 23, 2022, in Gölyaka district of Düzce province that is located in the Western Black Sea region of Turkey. The earthquake with a shallow focus is 0.82 km away from Kemeryani village of Gölyaka district, which is the nearest settlement. According to observation data, the highest acceleration value of the earthquake was measured as 407.76 gal (0.410 g) in the East-West component measured from the 8102 coded Düzce Central accelerometer station, which is one of the five accelerometer stations closest to the earthquake zone. There was no loss of life in the earthquake, in which 93 people were injured. However, damages occurred due to the earthquake in structures that were built before the year 2000 and did not receive good engineering and supervision services. It has been determined that the structures built after the year 2000 received good engineering and supervision services performed better. The purpose of this study is to ensure that the experience gained as a result of the investigations about the earthquake that occurred will be made permanent and usable. For this purpose, damage and collapses that occurred on the buildings due to earthquake are examined based on field investigation. The types and causes of damage that occurred on both reinforced concrete and masonry buildings are evaluated in detail with considering the conditions of the existing Turkey Building Earthquake Design Code. The seismological characteristics of the earthquake are also evaluated. In addition, the earthquake hazard of Düzce Province is evaluated together with the earthquakes experienced in the past years, which caused significant loss of life and property in the region.

Many dwelling houses from 79 administrative villages of 23 provinces were investigated by our research group from June to September in 2009. 84.5% of the houses investigated are masonry buildings. On the basis of research on the masonry buildings in the villages and small towns, the structural characteristics of the masonry buildings are introduced. To understand the primary weakness of rural houses, the typical status is investigated, including the foundation treatment, walls Rachel, structural concrete column and ring beam setting, etc. Ultimately, several important problems were turned up, such as the uneven settlement of foundation, low strength of masonry mortar, doors and windows with excessive opening rate, placing the purlin in the gable directly, no structural concrete column or ring beam, poor construction technology, etc. The common forms of seismic damage are researched and the causes are analyzed in the end.