Non-dimensional method of capacity limit states for the assessment of the safety level in the structures of large panel buildings.

In the article deals with the European safety issues of large-panel buildings from the point of view of exceeding the ULS. The proprietary assessment method was proposed under the name: Dimensional Limit States Method, which is dedicated to the assessment of the safety level in the structures of large-panel buildings. The work was based on many years of computer research conducted by the author. In the paper uses the proprietary construction model of the Wk-70 system building, presents the results for vertical reinforcement inserts.

Elasto-plastic analysis of high-strength concrete shear wall with boundary columns using fiber model

In this study, an experimental study and numerical calculations using fiber model were conducted for four high-strength concrete shear walls with boundary columns under low cyclic load. The boundary column and shear wall were divided into fiber elements, and PERFORM-3D finite element analysis software was used to carry out push-over analysis on the test specimens. The results show that the finite element analysis results were in good agreement with the experimental results. The proposed analysis method could perform elasto-plastic analysis on the high-strength concrete shear wall with boundary columns without distinguishing the categories of frame column and shear wall. The seismic performance of high-strength concrete shear wall with boundary columns was analyzed using the following parameters: axis compression ratio, height to width ratio, ratio of vertical reinforcement, and ratio of longitudinal reinforcement in the boundary column. The results show that the increase in the axial compression ratio causes the bearing capacity of the shear wall to increase at first and then to decrease and causes the ductility to decrease. The increase in the height to width ratio causes the bearing capacity of the shear wall to decrease and its ductility to increase. The ratio of vertical reinforcement was found to have little effect on the bearing capacity and ductility. The increase in the ratio of longitudinal reinforcement in boundary column resulted in a significant increase in the bearing capacity and caused the ductility to decrease at first and then to slowly increase.

Application of Artificial Intelligence Methods to Estimate Shear Strength of Reinforced Concrete Shear Wall

Shear walls are the type of structural systems that provide the lateral resistance to a building or structure. Lateral loads are applied on one plate and along the vertical dimension of the wall. These type of loads are usually transmitted to the wall collectors. Concrete shear walls have a considerable resistance to lateral seismic loading. Model prediction is required for the shear capacity of these walls to ensure the seismic security of the building. Therefore, a model is proposed to estimate the shear strength of concrete walls using an artificial intelligence algorithm. The input parameters of the neural network include the thickness of the reinforced concrete shear wall, the wall length, the vertical reinforcement ratio, the transverse reinforcement ratio, the compressive strength of the concrete, the stresses of the transverse reinforcement, the stresses of the vertical reinforcement, the ratio of the dimensions. The target parameter is the shear strength of the reinforced concrete shear wall. A total of 58 laboratory data was collected on concrete shear walls. The results of the research show that optimum artificial neural network with a specific number of hidden neurons can accurately estimate the shear capacity of reinforced concrete shear walls. The results indicate that the highest percentage of effect and the lowest percentage of effect have a target function. Additionally, the error rate obtained for predicting shear capacity is 7%, which is an acceptable error in this regard.

Parametric study of multi-story, perforated, partially grouted masonry walls subjected to in-plane cyclic actions

Finite element models were developed to assess the influence of several parameters on the load capacity, deflection, and initial stiffness of multi-story, partially grouted masonry walls with openings. The base model was validated with experimental data from three walls. The analyses indicated that the load capacity of masonry walls was considerably sensitive to the ungrouted and grouted masonry strengths and mortar shear strength; moderately sensitive to the vertical reinforcement ratio and aspect ratio; slightly sensitive to the axial stress; and almost insensitive to the opening size, reinforcement spacing, and horizontal reinforcement ratio. The deflection of the walls had well-defined correlations with the masonry strength, vertical reinforcement, axial stress and aspect ratio. The initial stiffness was especially sensitive to the axial stress and the aspect ratio, but weakly correlated with the opening size, and the spacing and size of the reinforcement.

Behavior of Partially Grouted Concrete Masonry Walls under Quasi-Static Cyclic Lateral Loading

Eight partially grouted (PG-RM) concrete masonry walls were tested to study the influence of the strength and width of blocks, the wall aspect ratio, the horizontal and vertical reinforcement ratio, and the presence of edge elements (flanges). The results were analyzed in terms of the failure mode, damage progression, shear strength, lateral stiffness degradation, equivalent viscous damping ratio, and displacement ductility. Additionally, the performances of some existing shear expressions were analyzed by comparing the measured and predicted lateral load capacity of the tested walls. Based on the results, a slight increment in the lateral stiffness was achieved when employing stronger blocks, while the shear strength remained constant. Besides, increasing the width of concrete blocks did not have a significant effect on the shear strength nor in the initial tangential stiffness, but it generated a softer post-peak strength degradation. Increasing the wall aspect ratio reduced the brittleness of the response and the shear strength. Reducing the amount of vertical reinforcement lowered the resulting shear strength, although it also slowed down the post-peak resistance degradation. Transversal edge elements provided integrity to the wall response, generated softer resistance degradation, and improved the symmetry of the response, but they did not raise the lateral resistance.