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To ensure the long-term safety and stability of bridge pile foundations in permafrost regions, it is necessary to investigate the rheological effects on the pile tip and pile side bearing capacities. The creep characteristics of the pile-frozen soil interface are critical for determining the long-term stability of permafrost pile foundations. This study utilized a self-developed large stress-controlled shear apparatus to investigate the shear creep characteristics of the frozen silt-concrete interface, and examined the influence of freezing temperatures (−1, −2, and −5°C), contact surface roughness (0, 0.60, 0.75, and 1.15 mm), normal stress (50, 100, and 150 kPa), and shear stress on the creep characteristics of the contact surface. By incorporating the contact surface's creep behavior and development trends, we established a creep constitutive model for the frozen silt-concrete interface based on the Nishihara model, introducing nonlinear elements and a damage factor. The results revealed significant creep effects on the frozen silt-concrete interface under constant load, with creep displacement at approximately 2–15 times the instantaneous displacement and a failure creep displacement ranging from 6 to 8 mm. Under different experimental conditions, the creep characteristics of the frozen silt-concrete interface varied. A larger roughness, lower freezing temperatures, and higher normal stresses resulted in a longer sample attenuation creep time, a lower steady-state creep rate, higher long-term creep strength, and stronger creep stability. Building upon the Nishihara model, we considered the influence of shear stress and time on the viscoelastic viscosity coefficient and introduced a damage factor to the viscoplasticity. The improved model effectively described the entire creep process of the frozen silt-concrete interface. The results provide theoretical support for the interaction between pile and soil in permafrost regions. [ABSTRACT FROM AUTHOR]

The reliable anchorage of carbon fiber-reinforced polymer (CFRP) tendons is a critical issue influencing the stable bearing capacity of bridge cables. This study introduces a novel CFRP single-strand extrusion anchoring structure, where the strand is compressed at its end. By integrating this with internal cone filler wrapping, we create a CFRP multi-strand cable composite anchoring system. This innovative design not only minimizes the overall dimensions of the anchoring system but also significantly improves its anchoring efficiency coefficient. An axisymmetric model was developed using ANSYS finite element software. The radial stress distribution and anchorage efficiency coefficient in the anchorage zone of Φ7 CFRP bar and Φ13.6 extrusion die were analyzed with varying parameters, such as chamfering, outer diameter, and length of the extrusion sleeve, and were validated through static load anchorage tests. The results indicate that the highest anchoring efficiency is achieved when four extrusion sleeves with a chamfer angle of 5°, an outer diameter of Φ14.4, and a length of 15 mm are connected in series, reaching a coefficient of 61.04%. Furthermore, this study proposes an anchorage structure where multiple extrusion sleeves are connected in series and sequentially compressed to overcome the limitations of increasing anchorage length for enhancing the anchorage coefficient. The test results demonstrate that with equal total anchorage length, connecting four 15 mm extrusion sleeves in series enhances the anchorage efficiency coefficient by 24.98% compared to a single 60 mm extrusion sleeve structure. [ABSTRACT FROM AUTHOR]

This paper mainly introduces the emergency repair process for small- and medium-span bridges. The causes of deterioration were analysed by investigating old bridges. After comparison and selection of schemes, the scheme of beam replacement was confirmed using a lightweight steel ultra-high performance concrete (UHPC) composite beam as the superstructure. The main components of the calculations and the design are introduced in detail. Finally, through the load test of the bridge, it was shown that the lightweight steel-UHPC composite beam had good performance and met the requirements of Highway Level I bearing capacity. The lightweight steel-UHPC composite beam described in this paper has the characteristics of high strength, light weight, fast construction, excellent working performance, and remarkable social and economic benefits. It can be popularised and applied in the emergency repair of small- and medium-span bridges and new bridges. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present paper, an experimental study was conducted to determine the factors affecting the point bearing capacity of pile foundations constructed in dry and saturated sandy soils. Model piles were installed as reinforced concrete bored piles cast-in-situ. Model pile foundations of various geometries resting at different depths in homogeneous sand of different saturation degrees (%0-100) were loaded statically to failure. The test results showed that the bearing capacity of piles did not significantly affect by the loading rate. At most 10% difference was observed in pile bearing capacity when the loading rate was between 0.7 and 2.5 mm/min. Subsequently, the load bearing capacities of the piles were determined at a specified constant loading rate. The point and total capacities of the piles were measured separately in the experiments, then test results were compared with theoretical values. Pile point capacities provided from pile load tests are smaller than the theoretical values. The differences between experimental and theoretical results have been attributed to the Nq values. The Nq values not only dependent on the internal friction angle of the soil but also the saturation degree of the soil, the pile diameter, and the effective stress. Nq values decrease since the pile length/pile diameter ratio increases. [ABSTRACT FROM AUTHOR]

The orthotropic steel bridge deck (OSBD) has been widely used in recent decades, benefiting from its advantages of lightweight and easy assembly. However, the longitudinal and transversal stiffeners of OSBDs are connected to the top flange plate through dense welds, which will easily introduce fatigue cracks. Hence, the composite bridge deck (CBD) system was proposed, adding a concrete layer over a steel plate to increase the sectional stiffness of OSBDs and reduce the fatigue stress amplitude. Furthermore, some new materials with extraordinary properties such as ultra-high-performance concrete (UHPC) and engineering cementitious composites (ECC) were used to replace the normal concrete, to improve the bearing capacity and crack resistance of CBDs. In this review, four kinds of bridge deck systems with different structural types including OSBD, steel-concrete, steel-UHPC, and steel-ECC CBDs were discussed. The flexural performance of four systems under sagging and hogging moments was reviewed, and close attention was paid to the crack resistance of the CBD system. In addition, the shear connection used in the CBDs was concentrated, and the shear behavior of some connectors including studs, perforated rib (PBL), and modified clothoid (MCL) shape shear connectors was investigated. The CBD structure assembled by duplicate profile steel parts proposed recently was introduced and discussed. [ABSTRACT FROM AUTHOR]

This paper presents an easily installed improved perfobond connector (PBL) designed to reduce the shear concentration of PBL. The improvement of PBL lies in changing the straight penetrating rebar to the Z-type penetrating rebar. To study the shear performance of improved PBL, two PBL test specimens which contain straight penetrating rebar and six improved PBL test specimens which contain Z-type penetrating rebars were designed and fabricated, and push-out tests of these eight test specimens were carried out to investigate and compare the shear behavior of PBL. Additionally, Finite Element Analysis (FEA) models of the PBL specimens were established and validated against the test results. Through FEA, the effects of concrete grade, perforated plate's aperture, Z-type penetrating rebar's diameter, Z-type penetrating rebar's bending angle, and bending length on shear behaviors were discussed. The results indicate that (1) Compared with PBL specimens with straight penetrating rebars, Z-type penetrating rebar can significantly improve the shear resistance and shear stiffness of the specimens. This enhanced performance can be mainly attributed to the increased adhesion of the transverse rebar. (2) By comparing the load-slip curve, the slip of PBL test specimens which contain straight penetrating rebar increases rapidly and the bearing capacity decreases rapidly after concrete craking, while the bearing capacity of Z-type penetrating rebar specimens decreases first and then increases gradually, showing better ductility. (3) The stress of the PBL shear connector with Z-type penetrating rebar is more uniform than the PBL shear connector with straight penetrating rebar, and the overall deformation is more uniform. (4) The higher the concrete grade, the higher the shear bearing capacity and the better ductility of the new PBL. Increasing the aperture of the perforated plate or the diameter of the rebar has a very limited effect on the improvement of the shear capacity of PBL. Through the systematic analysis of the mechanical properties of Z-type penetrating rebar PBL specimen, the experimental reference is provided for improving the structure and design of new type PBL. [ABSTRACT FROM AUTHOR]

The analytical model for calculating the bearing capacity of a pile, presented in the commentary to STN 73 1002 - Pile Foundations, gives a recommendation to reduce the pile's length in the calculation of the shaft resistance. The recommendation is based on Caquot-Kérisel's theory. Especially in the case of embedded piles, reducing a pile's length in the calculation can cause the shaft friction of the embedded pile to be neglected, and the calculated resistance of the pile is thus significantly lower. The results of instrumented static load tests of embedded piles were analysed. The main aim of the study was to verify the validity of reducing the pile's length in the analytical calculation of the shaft resistance. The results of the static load tests analysed did not show any reduction in the shaft friction on the embedded part of the pile. In the form of a parametric study, the effect of reducing the pile's length in the calculation of shaft friction was analysed for different dimensions of embedded piles. [ABSTRACT FROM AUTHOR]

Pile foundations are vastly utilized in construction projects where their capacities (pile bearing capacity, PBC) should be determined in different stages of construction. A highly reliable and accurate prediction model can lead to many advantages, such as reducing the construction cost, shortening the construction timeline, and providing safety construction. Hence, the aim of this study is the developments of statistical and artificial intelligence (AI) models for predicting bearing capacities of 141 piles. At the preliminary of the study, features or inputs of this study to predict PBC were selected trough simple regression analysis. Then, this study presents different kernels of support vector machine (SVM) technique, i.e., the dot, the radial basis function (RBF), the polynomial, the neural, and the ANOVA to predict the PBC. The aforementioned models were evaluated by several performance indices and their results were compared using a simple ranking system. The results showed that the SVM-RBF model is able to achieve the highest coefficient of determination, R2 values which are 0.967 and 0.993 for training and testing stages, respectively. It is important to mention that a multiple regression model was also employed to predict PBC values. The other SVM kernels were provided a high degree of accuracy for estimating PBC, however, the SVM-RBF model is recommended to be used as a powerful, highly reliable, and simple solution for PBC prediction. [ABSTRACT FROM AUTHOR]

This study provides an equation of bearing capacity for a rectangular footing placed on dense sand overlying loose sand and subjected to inclined concentric loading using the limit equilibrium followed by projected area method. The parameters varied were thickness ratio (0.00 to 2.00) of the upper dense sand layer, embedment ratio (0 to 2), friction angle of upper dense (41° to 46°) sand and lower loose (31° to 36°) sand layer, and applied load inclination (0° to 30°) for the parametric study. The highest and lowest increase in the bearing capacity were observed for a friction angle combination of 46°-36° and 41°-31°, respectively, at different thickness ratios. The bearing capacity obtained from the proposed equation was approximately 4.97 and 10.5 times its initial value at embedment ratios of 1 and 2, respectively. Bearing capacity was reduced by 20.55%, 54.58% and 87.90% for load inclinations of 5°, 15°, and 30° for friction angles of upper dense and lower loose sand layer combinations of 46° and 36° and at a thickness ratio of 2. The bearing capacity obtained from the proposed equation decreased by 99.89%, 66.04%, and 61.5% as the load inclination increased from 0° to 30° for embedment ratios of 0, 1, and 2. With respect to finite element results, the average deviation of the bearing capacity obtained from the proposed equation at embedment ratios 0, 1, and 2 was 14.56%, 18.71% and 23.56%, respectively. The proposed bearing capacity equation produced results that were consistent with those reported in the literature, with an average deviation of 10.71%. [ABSTRACT FROM AUTHOR]

The high volume of vehicles at Simpang Joglo, which caused traffic congestion, became a particular focus for the government. The construction of the bridge on this railway line of PT. Wijaya Karya (WIKA) is located at KM 105+499 to KM 105 +772, with a bridge stretch of 272.80 m and a width of 14.1 m. The problems raised in this study include the effect of the implementation of bored pile work on the environment, whether the solution to the problem affects cost and time, and how much the carrying capacity of the bored pile is at this stage, using qualitative research methods and quantitative research methods. After observations and interviews with the community, it can be known that the bored pile foundation work on the Railway Elevated Line Construction Project between Solo Balapan - Kadipiro at KM 104 + 700 to KM 107 + 000 (phase 1) has several impacts that affect the work environment and the community environment, including noise, road damage, air pollution, land collapse due to drilling damage to tools, etc. From this impact, there are several solutions, including repairing road facilities, changing tools, etc. From the results of the analysis of the calculation of the bearing capacity of the foundation at Pier 11, a value of 28135.397 kN was obtained. The benefits of this research are that it can find out problems and solutions for work, know the impact on time and cost, and know the carrying capacity of a bored pile. [ABSTRACT FROM AUTHOR]

In circular shield tunnels bearing high inner pressure or rectangular shaped shield tunnels, as the axial force at the segmental lining decreases, the bolt load at the segmental joint increases. It is essential to adopt high-stiffness segmental joints to improve the bearing capacity and control the deformation at the joint position. When designing high-stiffness segmental joints, the selection of ductileiron joint panel is crucial. In this study, two types of segmental joints with different joint panels were fabricated, and the effects of joint panel stiffness on the mechanical properties of segmental joints were analyzed through full-scale sagging and hogging bending tests. The results showed that the failure mode of high-stiffness segmental joint was similar to that of large eccentric compression section. According to the difference of panel stiffness, the failure modes can be specified into two types. If the stiffness is sufficient, the joint failure occurs due to the yielding of bolts; otherwise, it occurs due to the large deformation of ductile-iron joint panels. As for the design requirement of segmental joint, the stiffness of joint panel should be sufficient, i.e., the opening and failure of the joints are finally induced by the bolt deformation. Otherwise, before the plastic deformation of the bolts, the large deformation of the joint panels will occur under a bending-moment-dominant load, and the bearing capacity of the joints will greatly decrease. [ABSTRACT FROM AUTHOR]

The evaluation of the bearing capacity of shallow or deep foundations is a major and traditional problem This article deals with the estimation and analysis of this bearing capacity but with a probabilistic method (statistics) therefore the main objective of this work is to do a probabilistic analysis. To answer and achieve this goal, the work has two lines of research: a theoretical one which brings together a bibliographical synthesis on the estimation of the bearing capacity of a pile by the in situ method (in place) such as the pressuremeter test and the second axis is experimental reinforced by a statistical analysis. The results of the pressuremeter test used in the evaluation (determination) of the bearing capacity of a pile considered as a deep foundation which actually represents the abutment of a rail bridge. An experimental study is underway for pressuremeter test on several sites. The geotechnical data comes according to a study of the project for the construction of a deep foundation for a bridge in the region of Tissemsilt in Algeria, after having defined the pressuremeter profile and estimated the bearing capacity by the pressuremeter method, the reliability of the results was tested. by a probabilistic (statistical) analysis using the normal distribution. [ABSTRACT FROM AUTHOR]

Stone arch bridge is an important type in the early bridge construction process because of its beautiful shape, material saving and economic rationality. However, stone material will deteriorate after long-term operation, which results in a decrease in strength and bearing capacity of stone arch bridge. The vehicle load is increasing at the same time. Therefore, accurate evaluation of bearing capacity of stone arch bridge is essential to ensure safety. In this article, a three-span open-spandrel stone arch bridge was taken as research object. Firstly, the bridge damages were investigated and analyzed in detail, and bridge service state was evaluated. Then, based on the evaluation results of disease damages and considering stone material deterioration, a refined finite element model of stone arch bridge was established to analyze bending moment, axial force, strain and deformation. Finally, static load test was carried out to test vertical deformation and stress of arch ring, horizontal displacement of pier, settlement of foundation and development of cracks. The results show that static load test is the most accurate method for evaluating bearing capacity of stone arch bridge. The evaluation accuracy of finite element model based on material correction is in the middle, and the evaluation accuracy of disease damage assessment is the worst. In practical work, bearing capacity of stone arch bridge can be evaluated by combining the three methods with high accuracy and comprehensive results. [ABSTRACT FROM AUTHOR]

The footings laid in close proximity imposes a definite change in the behaviour of the adjacent footing, subsequently changing the behaviour of the nearby footings. The present study emphasises the behaviour of the nearby strip footings embedded at a different level by adopting the commercially available finite element analysis program, ABAQUS. The load-settlement behaviour, ultimate bearing capacity (UBC), and the failure patterns of adjacent strip footings are assessed by considering the Mohr-Coulomb failure criterion. The UBC is of the nearby footings (left and right) are estimated and represented in terms of interference factors (L/R) defined as the UBC of a footing in the presence of adjacent footing to that of same considered for equivalent isolated footing. The results reveal that a significant influence of the adjacent footing is experienced when the spacing between the footings (S/B) is lesser, and they behave as the single footing of greater width at S/B = 0.25 irrespective of the level of embedment depth. Furthermore, the influence of interference increases with the increase in the embedment depth of adjacent footing. It is found that the L is significantly more for a lower level of embedment depth, and the same increases with an increase in the embedment depth of the right footing but on the contrary R decreases. The increase in the peak interference factor, L-max for DL/B = 0.5 is 2.1% and 4.2% when DR/B = 0.75 and DR/B = 1.0, respectively. [ABSTRACT FROM AUTHOR]

A lot of fieldwork is required to assess the safe bearing capacity (SBC) of fine-grained soil using IS Code, along with performing shear parameters to determine angle of internal friction and cohesion. Standard penetration tests are conducted in order to obtain N-value of soil, and evaluating atterberg limits and dry soil density. Here, it is proposed that Adaptive Neuro-Fuzzy Inference System (ANFIS) is adopted to predict fine-grained soil's safe bearing capacity. For this, input parameters considered for ANFIS system are depth of foundation, dry density, liquid limit, plasticity index, Percentage fine fraction, width/Length ratio, and N-Value. A wide range of safe bearing capacity data from various site locations was investigated and trained on. Four different models were developed with variations in membership function for each input, all the models are used with a gaussbell type of membership function. Among the four, the third model is predicting the nearest value with an R2 of 0.9738. Based on the conclusion the ANFIS model is the most reliable technique for assessing the SBC of soils. Investigation of soil properties and estimation of safe bearing capacity will be having more difficulty with respect to skilled person to investigate and time required is also more as dimension of the footing changes SBC also varies. So, to overcome this type of problems my model will give you a best suitable and reliable SBC. [ABSTRACT FROM AUTHOR]

The actual use of solid or glued timber elements that are in direct or oblique transverse bending under single or repeated loads is not considered in the current standards. In particular, the formation of folds in the compressed zone of pure bending and obtained a significant margin of safety. Therefore, the concept of "calculated cross-section" is proposed in the article. It describes the distribution of deformations in the height of the cross-section and, also, the layer-by-layer connection between deformations and stresses in a section of bending timber elements by considering the formation of folds in the compressed zone under one-time short-term or repeated loads. Therefore, the method for calculating wooden beams from solid and glued timber using a deformation model was developed. The formation of folds in the compressed zone is predicted by the method of the pure bending zone by analyzing the distribution of stresses on height in the compressed and stretched zones of the calculated cross-section. [ABSTRACT FROM AUTHOR]

The load-bearing function of articular cartilage tissue contrasts with the poor load-bearing capacity of most soft hydrogels used for its regeneration. The present study explores whether a hydrogel based on the methacrylated natural polymers chondroitin sulfate (CSMA) and hyaluronic acid (HAMA), injected into warp-knitted spacer fabrics, could be used to create a biomimetic construct with cartilage-like mechanical properties. The swelling ratio of the combined CSMA/HAMA hydrogels in the first 20 days was higher for hydrogels with a higher CSMA concentration, and these hydrogels also degraded quicker, whereas those with a 1.33 wt% of HAMA were stable for more than 120 days. When confined by a polyamide 6 (PA6) spacer fabric, the volumetric swelling of the combined CSMA/HAMA gels (10 wt%, 6.5 × CSMA:HAMA ratio) was reduced by ~53%. Both the apparent peak and the equilibrium modulus significantly increased in the PA6-restricted constructs compared to the free-swelling hydrogels after 28 days of swelling, and no significant differences in the moduli and time constant compared to native bovine cartilage were observed. Moreover, the cell viability in the CSMA/HAMA PA6 constructs was comparable to that in gelatin–methacrylamide (GelMA) PA6 constructs at one day after polymerization. These results suggest that using a HydroSpacer construct with an extracellular matrix (ECM)-like biopolymer-based hydrogel is a promising approach for mimicking the load-bearing properties of native cartilage. [ABSTRACT FROM AUTHOR]

The bearings represent an important element in the mechanical structures, ensuring the proper functioning of the moving / dynamic elements. An important feature of the bearing is its durability, which is necessary for long-term use. This characteristic is influenced by the contact between the rolling element / ring and the rolling elements / balls or rollers. This paper proposes a comparative study of the influences of different types of cylindrical roller profiles proposed in the literature and by the author on the durability characteristic. There are 3 types of profiles, standard, Fujiwara and a profile calculated by the author based on the solid of equal strength. [ABSTRACT FROM AUTHOR]

The suspender of a suspension bridge is susceptible to corrosion due to environment, material, load, and other factors, which leads to the reduction of its bearing capacity with time, thus adversely affecting the safety and durability of the suspension bridge. Time-variant reliability analysis can consider the time-variant characteristics and uncertainties of each variable, and can better reveal the degradation of corrosion suspender resistance with time. However, due to the complex and highly nonlinear characteristics of the stress situation, the functional function of the suspender is often implicit, and the traditional time-variant reliability analysis method cannot be directly solved. To solve the problem of the implicit function of the suspender, An Adaptive Support Vector Regression with Extreme Response Surface (ASVR-ERS) method was proposed, and it was applied to the time-variant reliability analysis of corroded suspender of a suspension bridge. According to the corrosion characteristics of steel wire in suspenders, a hybrid constitutive model for calculating the ultimate bearing capacity of corroded suspenders was proposed. Furthermore, the time-variant reliability and residual life of corroded suspenders of a self-anchored suspension bridge were systematically studied. The results show that: Compared with the existing methods, the ASVR-ERS method can use fewer training samples to achieve higher computational accuracy. When calculating the ultimate bearing capacity of a corrosion suspender, the phenomenon of ductility degradation caused by steel wire corrosion in the suspender cannot be ignored, and the mixed constitutive model of the ultimate bearing capacity of a corrosion suspender is more reasonable. When the service time of the bridge is the same, the reliability of the suspender in the middle span of the main span is the smallest, and the reliability of the suspender in the full bridge gradually decreases from the bridge tower position to the middle span direction and the side span direction. The decrease rate of suspender reliability is the fastest at the beginning of corrosion and gradually slows down with the deepening of the corrosion degree. When the sheath has the minimum damage and the maximum circumferential damage and reaches life, the suspender section loss rate is between 10 % and 15 %. Compared with improving the safety factor of the suspender, delaying the breakage time of the sheath can improve the life expectancy of the suspender more obviously. • The ASVR-ERS method has high efficiency and accuracy, and can solve the problem of implicit function of complex structure. • The hybrid constitutive model for calculating the ultimate bearing capacity of corroded suspender is more reasonable. • Compared with the design safety factor, the influence of sheath life and damage form on suspender life is more obvious. • When the suspender reaches its life due to corrosion, its cross-sectional area loss rate is between 10 % and 15 %. [ABSTRACT FROM AUTHOR]

Recently, a new steel-UHPC composite deck system is used for long-span bridges, which uses the perfobond rib (PBL) shear connectors with a thinner steel perforated plate. Because the steel perforated plate is thinner, its failure mode may be different from that of thicker steel perforated plate. To explore the shear behavior of PBL shear connectors in this new composite deck system, five sets of ten specimens are tested in this study. The parameters of the hole diameter, D , the traverse rebar diameter, d s , and the perforated steel plate thickness, t s are considered. The failure modes, strain development versus loading, and some mechanical indexes are discussed. The experiments show that the PBL shear connector with a thinner perforated steel plate causes a shear failure, while the thicker one results in bending or bending-shear failure. According to FE (finite element) analysis, the orthogonal analysis is conducted to investigate the effect of each parameter and their interaction on the mechanical behavior. It is found that the ultimate capacity and stiffness are the most sensitive to the diameter of the traverse rebar, d s , and the perforated steel plate thickness, t s. In addition, a theoretical formula is proposed to predict the bearing capacity of PBL shear connectors. The proposed formula considers the relationship between shear strain and the dilation angle for the first time. The results show a good agreement with the experiments. The study in this paper provides a good reference for the application and optimization of PBLs with a thinner steel perforated plate in new steel-UHPC composite deck system. • Introducing a new steel-UHPC bridge deck with perforated steel plate as the shear connectors and longitudinal rib. • Shear behavior on PBL shear connector in the new steel-UHPC deck is conducted. • The influence of each parameter of PBL shear connector and its interaction on the structure is obtained. • The formula for the shear capacity of PBL shear connector in the new steel-UHPC bridge deck is presented. [ABSTRACT FROM AUTHOR]

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Copyright of Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji is the property of Gazi University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The spherical bearing is widely used in highways, bridges and long-span structures. In order to study mechanical properties of a large-scale spherical bearing, a full-scale finite element model of the spherical bearing was established by using ABAQUS software, and the mechanical properties of the spherical bearing under four working conditions were simulated respectively when the upper bearing plate had different inclination angles. The ultimate bearing capacity of the spherical bearing under vertical tension was analyzed emphatically. The research results show that, in practical applications, the change in bearing capacity caused by the inclination angle of the upper bearing plate should be considered, and the wedge-shaped part should be strengthened. [ABSTRACT FROM AUTHOR]

Understanding the load transfer mechanism and the load settlement behavior of non-connected piled raft foundations with cushion is so complicated. In the present research, based on the assumption of an axisymmetric cylindrical unit cell including pile, subsoil, cushion, and raft, an analytical model is developed and introduced. This model is capable of estimating the transferred vertical stress from raft to piles head and subsoil, compression of cushion, and differential settlement between pile head and subsoil. Also, an experimental test program has been introduced to investigate the behavior of non-connected piled raft foundations and to validate the proposed model. To represent the effectiveness of using non-connected piled raft with different cushion thickness, number, and length of piles measure with the unpiled raft, the load improvement ratio and the settlement efficiency ratio are used. According to the results, the minimum increase in the bearing capacity and the reduction in the settlement of non-connected piled raft to the unpiled raft are 42% and 38% respectively. Also, increasing the cushion thickness increases the differential settlement at the pile head elevation, and for a given number and length of pile, reduced the bearing capacity of the piled raft by 30%. The good agreement of model predictions with the experimental results is verified. The difference between the experimental and analytical values of the cushion compression above the pile head is within an acceptable range. [ABSTRACT FROM AUTHOR]

Loess soils cover approximately 10% of the Earth's land surface. Due to its honeycomb structure, this soil collapses under pressure and immediately settles when exposed to moisture. Using moisture and loading conditions prior to construction can have positive effects on the geotechnical properties of the soil and help to reduce its settlement. This study aims to investigate the effect of different installation methods of helical piles on microstructure of loess soils. A total number of 16 full-scale helical piles including single helix and double helix piles with spacing to diameter ratios of 1.5 and 3 were installed via wet and dry installation methods. These 3-m-long piles were installed at the site of Inche Borun, Golestan province, northeastern Iran. Pile static load tests were performed on a set of these piles to compare the effect of different installation methods. Furthermore, the behavior of Golestan loess was investigated by removing the soil in front of the other set of helical piles for element testing and SEM imaging. The results suggested that the combination of compressive installation load and water pressure increases the shear strength parameters of Golestan loess and accordingly, the bearing capacity of the installed helical piles. [ABSTRACT FROM AUTHOR]

Copyright of Mining of Mineral Deposits is the property of Dnipro University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Scientiarum Polonorum: Architectura is the property of Wydawnictwo SGGW and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study presented an experimental investigation on the degradation of mechanical performance of reinforced concrete (RC) columns with the reinforcements corroded under sustained loads. A total of ten RC column specimens were tested. The effects of different levels of sustained load (0%, 30%, and 60% of the designed ultimate bearing capacity Nu) and reinforcement corrosion (0%, 5%, 10%, and 20%) on the failure modes, ultimate bearing capacity, and axial load–axial deformation relationship were analyzed. The results showed that the coupling adverse effects due to the reinforcement corrosion and sustained load considerably exacerbate the mechanical deterioration of RC columns and turn the failure mode into a much more brittle manner. Compared with the control specimen L-0-0, the ultimate bearing capacity of the specimen L-4-20 could be reduced as much as about 42%. Based on the test results, an improved model was proposed to estimate the ultimate bearing capacity of corroded RC columns, in which the effects of the corrosion of both longitudinal reinforcements and stirrups and the corrosion-induced spalling of concrete cover were taken into consideration. The close agreements between the analytical predictions and test results prove the applicability of the model. [ABSTRACT FROM AUTHOR]

Piled raft foundations are sometimes used when the supporting soil has no adequate bearing capacity and the raft settlements exceed allowable values. This research investigates the bearing capacity of a foundation subjected to eccentric loads in both connected and non-connected piled raft foundations under 1 g. The load-settlement curves of a strip, square and circular raft are compared. The results illustrate that piled raft behavior is influenced by various factors such as pile length, spacing, shape, and eccentricity ratio in connected and non-connected cases. Test results indicate that connected foundations have greater bearing capacities and lesser settlements in larger pile spacing (S/D = 6), while non-connected foundations have higher bearing capacities and lesser settlements in lesser pile spacing (S/D = 3). Moreover, both the pile length in a connected piled raft system and pile spacing in a non-connected system affected the bearing capacity remarkably. The bearing capacity of the square and circular foundations at S/D = 3 was greater for the non-connected pile (19.8 and 15.8 kg/cm2 receptivity) than the connected pile (18 and 14.1 kg/cm2), while at S/D = 6, the bearing capacity of the foundations was greater for the connected pile than the non-connected pile. However, in both cases, the bearing capacity was enhanced and the settlements were reduced. The effect of various parameters is also evaluated and discussed in this study. [ABSTRACT FROM AUTHOR]

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Permanently shadowed regions (PSRs) are abundant at the lunar poles. They experience no direct sunlight and reach temperatures as low as 30 K. PSRs are of interest as evidence suggests that some may contain water ice (H2O/OH‐), which could provide a record of the evolution of volatiles in the inner solar system. This water ice is also a critical resource for life‐support systems and rocket propellant. A better understanding of mechanical properties of PSR regolith, such as its bearing capacity, will help optimize the design of future exploration rovers and landers. Thirteen boulder tracks were identified on the edge of, or inside, south polar lunar PSR enhanced imagery and used to estimate the strength of the PSR regolith at latitudes of 70° to 76° in sites with maximum annual temperatures of 65 to 210 K. PSR boulder track features are similar to those observed in highland, mare, and pyroclastic regions of the Moon, implying similar properties of the regolith. Measured features were used to estimate bearing capacity for PSR regolith at depths of ~0.28 to 4.68 m. Estimated bearing capacity values suggest that these PSRs may be somewhat stronger than highland and mare regions at depths of 0.28 to 1.00 m. Bearing capacity in these PSRs is statistically the same as those in other regions of the Moon at depths of 1.00 to 2.00 m. The results of this study can be used to infer bearing capacity as one measure for the trafficability of lower‐latitude PSRs of the type measured here. Plain Language Summary: The polar regions of the Moon contain areas that never experience sunlight, known as permanently shadowed regions (PSRs). These regions are thought to contain uneven distributions of water ice deposits. To access PSRs and their possible water deposits, we must first understand the strength of the soil at these locations to safely traverse them. Thirteen boulder tracks were identified on the edge of, or within, PSRs in the lunar south polar region using images taken by the Lunar Reconnaissance Orbiter. These images were processed to enable the measurement of boulders and their associated tracks. The tracks identified within PSRs have similar appearances to those identified outside PSRs in other regions on the Moon. The strength of soil within PSRs was estimated from the measurements taken and was shown to be at least as strong as highland and mare regions of the Moon at relatively shallow depths, although the studied PSRs show no evidence for the presence of water ice. Analysis shows that PSRs of the type measured here should be able to bear rovers at depths of at least ~30 cm. In situ measurements are required to confirm and better understand the mechanical behavior of PSR regolith at shallow depths. Key Points: Boulder tracks were measured from orbital imagery, and the bearing capacity of regolith in permanently shadowed regions was estimatedRegolith in permanently shadowed regions appears to be as strong as regolith found in other regions of the MoonBoulder track measurements could be used to remotely estimate the traversability of PSRs for future exploration rovers [ABSTRACT FROM AUTHOR]

Dynamic and static load (DSL) tests provide an important tool for safety inspection of bridge structure. The test results reflect the actual working condition, bearing capacity and working performance of the bridge structure, laying a scientific basis for the operation safety of the bridge. This paper carries out the DSL tests on a rigid-frame bridge, details the loading plans and test process, and analyzes the stress state under static loads and the dynamic properties under dynamic loads. The results show that the bridge belongs to the elastic state under design load, and satisfies the requirements of the design and normal use in terms of bearing capacity, stiffness and working performance. The inspection method and findings of this research provide important references to the DST testing and evaluation of similar bridges. [ABSTRACT FROM AUTHOR]

Accurate determination of the ultimate bearing capacity (UBC) of shallow foundations is vital for the safety of structures and buildings. Due to the inherent spatial variability characteristics of soil properties, some new approaches are needed to accurately determine the UBC of shallow foundations. The objective of this study is to develop a hybrid least squares support vector machine (LSSVM) and an improved particle swarm optimization (IPSO) algorithm for determining the UBC of shallow foundations. To validate the hybrid IPSO-LSSVM model, a comparison of the predictions was carried out among different models and theoretical methods. Three statistical indexes, namely the root-mean-square error (RMSE), the mean absolute error (MAE) and the correlation coefficient (R) were employed to measure and evaluate the performance of these models. The results showed that the developed hybrid IPSO-LSSVM model can be used for determining the UBC of shallow foundations with high accuracy. [ABSTRACT FROM AUTHOR]

Abstract Considering engineering practices in terms of decrease in the matric suction of unsaturated soil with increasing embedded depth, this study, employing a new global optimization algorithm on the basis of radial movement optimization (RMO), focused on investigating the critical slip surface and ultimate bearing capacity of a rough strip footing on unsaturated soil subjected to vertical load. Based on upper-bound limit analysis theorem, an equation for calculating the ultimate bearing capacity of unsaturated soil has been established. The data structure of RMO was improved by considering self-feedback of the particles. The results show that the improved radial movement optimization can be successfully applied to accurately and stably search the critical slip surface and subsequently calculate the ultimate bearing capacity on unsaturated soil. It also found that, compared with no matric suction, the critical slip surface determined considering the matric suction of unsaturated soil is larger and deeper, and the corresponding ultimate bearing capacity is also significantly improved. [ABSTRACT FROM AUTHOR]

Abstract A concept of an adjustable elliptical journal bearing with variable elliptical ratio was proposed in order to suppress the vibration amplitude of a rotor under synchronous unbalance load at normal speed operating condition. In numerical simulations, dynamic lubrication program is programmed and it could predict the journal center orbits of the bearing. In experiments, adjustable elliptical journal bearing device and testing system are established. With the elliptical ratios adjusting from 0 to 0.7, journal vibrations are simulated and tested. The results obtained from the experiments are in good agreement with that from the numerical simulations. The results indicate that the effects of vibration suppression are satisfied. The proposed adjustable elliptical journal bearing provides an effective way in forced vibration suppression. Highlights • Dynamic Lubrication Program is established to predict the dynamic journal orbits under synchronous unbalance load condition. • The vibration suppression trends of experimental investigation are in good agreement with the numerical simulation results. • Adjustable elliptical journal bearing has a good effect in vibration suppression under unbalance load. • The vibration suppression effect is more oblivious at vertical than that of horizontal. [ABSTRACT FROM AUTHOR]

Design of modern thin-walled metal structures is widely used around the world. In recent decades, more comprehensive research is carried out to investigate the behaviour of various thin-walled structures. Generally, the structure with regular geometry is investigated. In various countries such as USA, Russia, and the European Union issued the standards on regulation of the construction, design and maintenance of thin-walled structures. The actually used period of tanks usually is longer than recommendatory period. Recommendatory maintenance period of metal tanks is 15-20 years. Therefore, for such structures one of the most considerable questions is the residual load bearing capacity beyond the end of the maintenance period. This phase of using of structures is associated with complex investigation and numerical analysis of thin-walled structures. In this paper the load bearing capacity of the steel wall of the existing over-ground vertical cylindrical tank in volume of 5,000 m3 with a single defect and with a few contiguous local defects of the shape is analyzed. Calculations carried out are taking into account all the imperfections of the wall geometry. A major goal of the research - developing a realistic numerical model of the object analyzed, taking into account all the imperfections, determining the wall stress and strain state, exploring the places of extreme points, calculating the residual load bearing capacity of the tank and scrutinizing possible strengthening schemes for defective areas. [ABSTRACT FROM AUTHOR]

Highlights • An innovative stiffened X-joints with good performance in tubular structures. • 15 specimens are experimentally studied with corresponding numerical verification. • Parametric study via finite element analysis reveals essential mechanical mechanism. • Strength prediction equations are concluded with corresponding boundary conditions. Abstract An innovative stiffened circular hollow section (CHS) X-joint is introduced herein, which has been used in offshore long-span transmission towers due to its higher bearing capacity in comparison with traditional CHS X-joint. A total of 15 specimens are employed for the experimental study to gain insight into its mechanical characteristics. Corresponding finite element (FE) analysis is thus conducted. The numerical results are compared with that by tests, and a good agreement is found, which verifies the validity of the setup in the finite element modelling and analysis. By using the settings, a total of 480 joints are numerically modelled and corresponding load-displacement curves and ultimate bearing capacities are obtained by FE analysis. Parametric sensitive study results show that the bearing capacities of corresponding unstiffened X-joint and chord rings could be used for predicting the strength of stiffened X-joints. The predicted results are shown to be in good agreement with that from numerical and experimental studies, and the equations proposed for prediction are applicable for a wide range of joint parameters. In this survey, the stiffened joint is observed to provide strength enhancement up to 811% in comparison with the traditional unstiffened X-joint, which proves that the stiffening method employed herein is capable of improving the bearing capacity greatly. [ABSTRACT FROM AUTHOR]

To study the flexural behavior of a composite beam, original single and double bamboo beams (SBBs and DBBs, respectively) and sprayed lightweight composite mortar-original bamboo composite beams (SCBs and DCBs) were designed and subjected to a four-point bending test based on the moisture content of the original bamboo. The failure modes, bearing capacity, and initial flexural rigidity of all of the beams were analyzed. Also, the strengthening effect of the lightweight composite mortar on the flexural behavior was studied. The results showed that a higher moisture content in the bamboo degraded the anti-slip property of the bond interface between the lightweight composite mortar and bamboo. The moisture content of the bamboo should be kept at approximately 20% before spraying. The initial flexural rigidity and bearing capacity of the DBBs were approximately 2.5 times and twice that of the SBBs, respectively. The initial flexural rigidities of the SCBs and DCBs were approximately 3.8 and 5.7 times that of the SBBs and DBBs, respectively. The ultimate load bearing capacity of the composite beams was approximately 1.5 times that of the original bamboo beams. It was shown that the lightweight composite mortar had a remarkable strengthening effect on the flexural behavior of the original bamboo. [ABSTRACT FROM AUTHOR]

Highlights • The SNSM technique can improve the flexural behavior for the large-scale RC beam. • Damaged-beams strengthened still exhibit good fatigue flexural behavior. • The damage of test beams mainly accumulated at the initial stage of fatigue cycles. • A predicted model of residual stiffness and bearing capacity were established. Abstract The effectiveness of the fatigue behavior of the large-scale reinforced concrete (RC) beams strengthened with side near surface mounted (SNSM) carbon fiber-reinforced plastics (CFRP) was assessed. Six RC beams (three static beams and three fatigue beams, strengthened with SNSM non-prestressed and prestressed CFRP strips) were tested to investigate the effects of the different loading and strengthening methods on the flexural fatigue performance of the beams. In order to simulate the existence of a certain degree of initial damage when the service beams were strengthened, the fatigue test beams were strengthened after they had been subjected to 2 million fatigue cycle loading, and then continued to be subjected to 500,000 fatigue cycle loading. The results showed that the flexural capacity and ductility of static strengthened beams were obviously higher than that of the un-strengthened beam, and the residual flexural capacity of the fatigue test beams was significantly lower than those of the static test beams. In terms of fatigue resistance, the prestressed CFRP strengthened beam was superior to the non-prestressed CFRP one; the tests beams were better after being strengthened than before. The damage of the strength of the concrete and steel bars was mainly accumulated at the initial stage of fatigue cycle loading, where the stiffness of the test beams decreased rapidly. The steel bar strain, concrete strain and mid-span deflection of strengthened beams after 2.5 million loading of fatigue cycles were basically the same as those of 2 million one, which indicated that the fatigue flexural behavior of the strengthened beams was enhanced significantly. Finally, the predicted models of static mid-span deflection and fatigue residual flexural capacity for the SNSM strengthening beams were derived and validated. [ABSTRACT FROM AUTHOR]