In most of the tall buildings, a portion of the lateral load is carried by the shear walls. Such shear walls usually have openings for doors or windows. For interactive action of the shear walls existing at the two sides of the openings, the two shear walls are connected by so called "connecting beams" and hence, coupled shear walls are produced. In some cases, the necessary stiffness to withstand the lateral load may not be afforded because of the low depth of the connecting beams. In order to increase the capacity of the coupled shear wall, beams with high stiffness will be added to the system at particular levels and so, stiffened coupled shear wall will be produced. Such walls are under axial load resulting from their weight, and the axial load affects their behavior because of their excessive height. In this paper, a simple formulation for determining the critical load of the stiffened coupled shear wall under gravity force has been proposed using continuum medium assumptions, and then several examples have been solved using the proposed method. In order to indicate the capability of the proposed method, the results arising from the proposed method have been compared to the results arising from the ANSYS software model. Then, the effects of the stiffness and the position of the stiffening beam on the critical gravity load of the stiffened coupled shear wall have been investigated.

One-dimensional view of optimized design of engineering systems focusing on costs without considering other aspects such as risk and uncertainty in engineering design can increase risks during the operation of that engineering system. This paper indicates that if there are uncertainties in design parameters this cannot always cause poorly system operation, whereas may strengthen that system operation. For this purpose, a gravity retaining wall is optimized and the optimal dimensions of that retaining wall are calculated. Then the effect of uncertainties, which are in the design parameters of that optimal gravity retaining wall, on the stability factors is calculated. Finally, using the concept of reliability, the risk in the safety factors of the retaining wall is obtained. In this paper, it is shown that if there is 10% uncertainty in design parameters the uncertainty propagation on safety factors is about (-80, +345)%, but this uncertainty propagation can increase the reliability(positive aspect of uncertainty) and risk(negative aspect of uncertainty) with a probability of 98. 6039% and 1. 3961% respectively. Then using the reliability block diagram, the total amount of reliability and risk for the gravity retaining wall is calculated which are equal to 79. 3169 and 20. 6830%, respectively. The innovations of this paper can be listed as below: 1) using Self-Adaptive Genetic Algorithm and Many Objective Genetic Algorithm, which have been used to optimize the retaining wall and calculate the uncertainty propagation on safety factors respectively. 2) Calculating reliability and risk using fuzzy set theory. 3) using reliability block diagram (RBD) to calculate the overall reliability and risk.

Due to heavy rainfall, underground water level and pore water pressure increase each year, which can cause failure of the earthen slopes. Retaining wall is one of the main structures that is used to increase the earthen slopes stability. In the present study, the stability of earthen slopes relative to the critical hydrological cases was simulated by Slope/w software and the pore pressure behind the retaining walls over 10 meter height which causes to instability was simulated using Seep/w software. The studied parameters are: precipitation intensity, soil type, position and the diameter of drainage. Also the kind of drainage has been considered as a variable parameter and horizontal and chimney drainages were used. Results showed that for fine grained soils with intensive rains condition, using of one horizontal drainage could not provide the stability of retaining wall. While in the same conditions, for coarse grained soils, the retaining wall will be stable by using of one horizontal drainage and drainage will be able to discharge all of the excess water behind the retaining wall. Also the chimney drainage system provided the best results and the stability of the retaining wall did not face any danger under the worst circumstances. For overturning moment and water pore pressure behind the wall, linear and non-linear regression relations were produced in dimensionless form. The accuracy of the regression relations were proper and the acceptable results could be expected.

Objective: To determine the pattern of stability changes as a reflection of early healing around single-stage roughened-surface implants in humans utilizing resonance frequency analysis (RFA).Materials and Methods: Hundred twenty-five patients who demanded dental implants were treated with two different implant (Nobel Biocare ReplaceTM and StrummanTM ITI) systems. Bone type was classified into four groups. RFA was used for direct measurement of implant stability on the day of implant placement and consecutively at 14, 30 and 60 days after placement. The data were analyzed with Student t test and regression analysis.Results: Three-hundred four roughened surface implants placed in the maxilla and mandible were evaluated. In ReplaceTM implants the lowest mean stability measurement was at 30 days for all bone types and the stability did not change significantly in any of the bone types (p>0.05). ITITM implants demonstrated the lowest stability at 60 days for type 1 and 30 days and baseline for type 2, 3 and 4 bones. In addition, there was significant differences in implant stability between bone types 1 and 4 (P<0.001), 2 and 3 (p<0.05), and bone types 3 and 4 (P=0.07) at all aforementioned times in ITITM implants. In ReplaceTM implants, regarding the implant diameter, contrary to ITI implants, no significant stability changes were detected (p>0.05). No significant difference was observed regarding gender, age and lengths in both systems.Conclusion: In comparison to ITITM implants, ReplaceTM implants revealed no significant difference in the pattern of stability changes among different bone types.

The safety evaluation of retaining structures, especially in cases of potential instability or disaster, frequently depends on empirical methods that apply overall safety factors. In this article, an innovative approach employing probabilistic methods to assess the reliability of gravity retaining walls, considering uncertainties in parameters and their inherent variability, has been introduced. This study applies First Order Reliability Method (FORM) to assess the influence of construction defects and soil-structure friction on gravity wall reliability. his approach represents notable progress over traditional empirical methods, which rely on total safety factors and frequently manage uncertainties arbitrarily. The paper is indeed novel as it integrates probabilistic methods into the analysis of gravity retaining wall stability, offering a more nuanced understanding of the reliability of these structures. This contribution seeks to enhance safety assessments and rehabilitation strategies in civil engineering practices, with a focus on addressing uncertainties in geotechnical parameters and construction defects.

The current paper presents the free vibration characteristic of axially moving conical shells made of shape memory alloy based on Donnell’, s shell theory. The material behavior is simulated based on the BoydLagoudas model. By applying the suitable airy function, the strain compatibility equation, and the Galerkin method, two sets of equations of motion are obtained. The compatibility equation is solved by using the steady-state form of equations and employing the suitable flexural mode shape concerning radial displacement. The effects of moving in the axial direction and using the SMA are investigated with the aid of the frequency responses curves. The phase transformation would decrease the quantity of the critical velocity. The results have been evaluated by means of the available data.

One of the main challenges in designing of thin-walled open section beams is lateral-torsion buckling mode. Due to the access for piping, electrical and other devices, inserting cut-outs in web are inevitable.This paper deals with the effects of different parameters in lateral-torsion buckling of plate girders. Lateral-torsion buckling loads of more than 700 plate girders are calculated with opening in different shapes, dimensions and locations by Ansys 5.4. The study is performed using numerical approach and the results are compared together. Three kinds of cut-outs including square, circular and hexagonal are selected. An extensive parametric studies is conducted to study the influence of cut-out dimensions, thickness, area, location and distribution along the beam length. Finally optimum scheme is obtained in order to have better estimation load carrying capacity of open-section beam.