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An analysis of the damage caused to vessels by collisions shows that the wreck of most struck ships is mainly due to underwater damage developed because of the accident. Such damage is caused, as a rule, by the presence of bulbs on striking ships that have high longitudinal rigidity and strength exceeding the load-bearing capacity of the framing system several times. Scientists in many countries are looking for ways to reduce the consequences of collisions with ships that have bulbs. Based on the results of the research, schemes for modernizing the forward end of ship hulls by installing bulbs with increased longitudinal compliance to reduce the consequences of ship collisions were proposed, and recommendations were developed for the selection of their characteristics, which make it possible to avoid underwater holes on a struck ship. Bulbs with increased longitudinal compliance were designed using methods of plastic limit analysis. The effectiveness of a modernized deformable bow structure was studied using ANSYS LS-DYNA non-linear finite element method computations. The developed technical solutions ensure that in case of collision in the underwater part of a struck vessel, the deformations of the framing systems will remain insignificant, thereby avoiding the appearance of damage below the waterline.

The shear wall is one of the most important systems to resist lateral loads in the building. In addition to controlling the lateral displacement of the structure and dealing with the lateral force, this system significantly increases the stiffness of the structure. The purpose of this article is to investigate the nonlinear behavior of semi-supported steel composite shear walls at the edges under monotonic and cyclic loading near- and far-fault. In this article, after verification, firstly, the semi-supported steel shear wall is modeled and analyzed using ETABS software to select the boundary members and the critical opening. Then, the base model of the semi-supported steel shear wall is converted to a semi-supported composite shear wall, and finally, it is modeled and checked using ABAQUS software. Among the investigated variables are reducing the thickness of the concrete coating on both sides of the steel plate of the wall, using concrete coating on one side of the steel plate of the wall, and increasing the thickness of the steel plate of the wall. The results showed that the addition of concrete to the SSSW model (converting the model to SSCSW) increases the initial in-plane hardness by 350%. Also, when concrete was added to the SSSW model, the ductility increased by 150% in two states near and far from the fault. Comparing the ultimate strength (peak of the cyclic diagram) also showed that regardless of the type of cyclic loading pattern, the calculated value for SSCSW is 28% higher than SSSW.

Geosynthetics are man-made materials used to increase the tension, compression, and shear characteristics of soil. Geogrid-reinforced material is regarded as one of the most widely used soil reinforcements. The Abaqus software (Ver. 2017) is used to simulate a 3-D fine sand model. The load-carrying capacity is investigated for both unreinforced and geogrid-reinforced fine sand supporting a 2.0m x 2.0m square footing. The relative density (Dr) of un-reinforced fine sand is 40%, the geogrid axial stiffness (J) used in the analysis varies at 250 kN/m, 500 kN/m and 1000 kN/m. The bearing capacity ratio (BCR) of geogrid-reinforced fine sand is influenced by the use of geogrid-layers with different axial stiffnesses (J). The influence of geogrid axial stiffness is evaluated using four investigated parameters: geogrid-layers number (N), vertical spacing (h/B), geogrid width/length (b/B), and first geogrid-layer depth (u/B). The results show that the numerical model validation agrees with the experimental results of Hotti and Gupta with an agreement ratio of 98% and 93%, respectively. The geogrid-reinforced fine sand with appropriate dimensions and proper geogrid-layers number has significantly increased the square footing bearing capacity. The load-bearing capacity of geogrid-reinforced fine sand increases with geogrid axial stiffness. The bearing capacity ratio is 1.45 and 2.13 when the geogrid axial stiffness increases from 250 kN/m to 500 kN/m and from 250 kN/m to 1000 kN/m, respectively. The most efficient and economical values of (u/B), (b/B), (h/B) and (N) are 0.30, 3.0, 0.15 and 3.0 for all values of geogrid axial stiffness, respectively.

Shallow foundations are often the most economical option for building support, as they distribute structural weight to soil layers, require minimal earthwork, and do not necessitate specialized machinery. The most common type of soil in the city of Karbala is sandy soil. It is granular and loose by nature which has a relatively low bearing capacity. According to previous studies, the soil weakness is one of the problems with shallow foundation construction. Thus, the aim of this study is to improve the properties of the soil using geogrid reinforcement. Three critical parameters are examined, including depth, size, and number of geogrid layers in the soil reinforcement process to increase bearing capacity and decrease soil settling. The effect of geogrid depth (u) was studied by considering four depth ratios (u/B = 0.5, 1.0, 1.5, and 2.0) in order to determine the ideal depth of the geogrid layer, where (B) refers to the width of the footings. The results indicated that a decrease in depth ratio significantly increased the bearing capacity of footings built on reinforced soil layers compared to those built on natural soil, and the settlement reduction ratio (SRR) also increased. The size of the geogrid layer (i.e., width of the geogrid layer (b) was evaluated by evaluating four size ratios (b/B = 1.5, 3.0, 4.5, and 6.0). With an increasing size ratio of the geogrid layer, the bearing capacity ratio (BRC) was significantly improved. Additionally, the study examined the optimal number of geogrid layers, focusing on single and multiple layers with N = 1, 2, 3, and 4. The results showed a higher BRC for footings on reinforced soil layers, as well as a significant rise in SRR with an increase in the number of geogrid layers. Finally, it was concluded that the optimal depth ratio was u/B = 0.5, the size ratio was b/B = 4.5, and reinforced with three geogrid layers, which provided the highest bearing capacity and SRR. The experimental test results were verified by comparing them with those calculated using theoretically developed models. The variation between the experimental and theoretical results is reasonable, confirming that the experimental testing results exhibit a high degree of accuracy.

This experimental investigation describes an extensive series of reduced laboratory scale tests, conducted on circular and ring footing models rested on a geogrid reinforced cohesionless soil. The study examined the impact of several factors at different relative sand densities, such as the inner to the outer diameter ratio of the ring footing, the number of geogrid reinforcements, the depth of the initial reinforcement, and the vertical spacing between the geogrids, as well as the geogrid stiffness. The results indicated that the optimum diameter ratio of ring footings resting on loose or medium-dense cohesionless soil is 0.40 at which the maximum bearing capacity is reached, leading in a cost-effective design of the footings, while for the dense soil, a diameter ratio of 0.45 is the optimal ratio. Also, the results indicated that the optimum number of reinforcement layers which after the bearing capacity improvement can be considered negligible is three layers for the circular footing and four layers for the ring footing model. To achieve the maximum increase in bearing capacity, the study identifies optimal values for the depth of the first geogrid reinforcement layer and the vertical spacing between reinforcements, which apply to circular and ring footing. While the stiffness of the reinforcement has a significant effect on the bearing capacity, this effect is not proportional.

Abstract A collection of feed forward neural networks (FNN) for estimating the limit pressure load and the according displacements at limit state of a footing settlement is presented. The training procedure is through supervised learning with error loss function the mean squared error norm. The input dataset is originated from Monte Carlo simulations for a variety of loadings and stochastic uncertainty of the material of the clayey soil domain. The material yield function is the Modified Cam Clay model. The accuracy of the FNN’s is in terms of relative error no more than $$10^{-5}$$ 10 - 5 and this applies to all output variables. Furthermore, the epochs of the training of the FNN’s required for construction are found to be small in amount, in the order of magnitude of 90,000, leading to an alleviated data cost and computational expense. The input uncertainty of Karhunen Loeve random field sum appears to provide the most detrimental values for the displacement field of the soil domain. The most unfavorable situation for the displacement field result to limit displacements in the order of magnitude of 0.05 m, that may result to structural collapse if they appear to the founded structure. These series can provide an easy and reliable estimation for the failure of shallow foundation and therefore it can be a useful implement for geotechnical engineering analysis and design.

Introduction. Analytical and numerical study of truss nodes made of square hollow sections (SHS) with local fibre concrete filling is presented. The analysis of numerical calculation of a fibre concrete element as a beam on an elastic base as a local reinforcement of a truss node made of SHS under the action of the concentrated load from the adjacent strut is performed. The bearing capacity of a node with the direct adjacency of struts to the chords of trusses made of S+HS is almost completely determined by geometry and physical and mechanical characteristics of truss elements made of SHS. With the cross-section of the elements selected on the basis of the calculation of the bars, the load-bearing capacity of K-type connections may not be ensured. In this case it is possible to change the dimensions of the cross-section of a truss node made of square hollow sections. In the existing Russian normative documents, there is no data on the calculation and design of reinforcement of truss nodes made of square hollow sections by filling with concrete. In this connection, it is important to develop simple and reliable methods of strengthening such nodes, as well as appropriate methods of their calculation. The purpose of the work is to develop a methodology for calculating the fibre concrete block of analytical dependencies to determine the bearing capacity under concentrated load.Materials and methods. The research method based on the numerical modelling of local reinforcement of the node with fibre concrete is used. Materials for the nodes: chord and struts of the node — steel of S255 grade according to GOST 27772–2015 with design resistance 240 MPa, local filling — fibre concrete with elastic modulus not lower than 27,000 MPa and design resistance to compression Rb = 11.5 MPa.Results. The main results of the work consist in the analytical study of truss nodes made of square hollow sections locally reinforced with fibre concrete block, the development of a method for calculating the fibre concrete block as a beam on an elastic base based on the results of numerical experiments in the software package АNSYS.Conclusions. The significance of the obtained results for the construction industry consists in the fact that the possible approaches to the definition of different methods of calculation of fibre concrete block as a part of reinforced nodes of trusses made of square hollow sections were considered in order to reduce metal consumption and deformability. The results obtained in numerical studies of the base stiffness factor of fibre concrete block and the results obtained using the software package АNSYS showed that they are close to the results of calculating the stiffness factor of fibre concrete block in locally reinforced nodes of trusses made of square hollow sections reliably.

Introduction. The available methods of assessment of bearing capacity by deformations of foundations mainly take into account single static loads of short duration or cyclic loads with unchanged values during the whole period of operation. The effect of cyclic loading of non-stationary regimes on the behavior of soil bases is practically not studied. In this connection, the research was carried out to develop a method for calculating the settlement of the bearing capacity of clay foundations under block cyclic loading.Materials and methods. To achieve the purpose of this paper, experimental studies of clay foundations in triaxial compression and tray test devices, as well as theoretical studies to determine the bearing capacity and settlement of clay foundations under different loading regimes were carried out.Results. On the basis of existing calculations of bearing capacity and settlement of foundations and the study of the behavior of clay soils under cyclic loads, the equations in compact form are obtained, which make it possible to take into account the peculiarities of deformation of clay soils significantly reducing the complexity and accuracy of the calculations. The development of methods for calculating the bearing capacity and settlement of clay foundations under block cyclic loads is at a sufficiently high level.Conclusions. A method for calculating the bearing capacity of clay foundations under block cyclic loading is proposed and an engineering method for calculating the settlement of clay foundations is developed, based on the method of layer-by-layer summation, which takes into account the simultaneous change in the spatial stress-strain state and mechanical characteristics of soils in the process of mode block cyclic loading.

The application of steel short piles in practical engineering is restricted due to its unclear bearing mechanism. However, due to advantages such as low cost, high strength, minimal soil displacement, easy construction, and convenient transportation, these piles are widely used in photovoltaic power projects in desert areas. In order to accurately reveal the horizontal and vertical bearing performance of steel piles in desert regions, horizontal load tests for different types of steel piles (including cross-sectional shape, cross-sectional area, and burial depth) and vertical compression and uplift load tests were conducted in a specific sandy site. The study analyzed the influence of parameters such as cross-sectional shape, cross-sectional size, and pile length on the bearing performance of steel piles. Research findings indicate: (1) The horizontal bearing performance of pipe piles and H-shaped steel piles is signifi-cantly better than that of C-shaped steel piles and trough-shaped steel piles. Compared with C-shaped steel piles and trough-shaped steel piles, pipe piles and H-shaped steel piles exhibit advantages in resisting wind loads, with the horizontal bearing performance of H-shaped steel piles closely related to the cross-sectional size and pile length. (2) The vertical bearing capacity of pipe piles and H-shaped steel piles is also significantly better than that of C-shaped steel piles and trough-shaped steel piles. Moreover, the compressive and tensile bearing performance of H-shaped steel piles is positively correlated with cross-sectional size and pile length. When the length of pile is the same, the vertical bearing capacity of H-shaped steel piles is similar to that of pipe piles. (3) The bearing performance of H-shaped steel piles is more prominent compared to other pile types (C-shaped steel piles, trough-shaped, and pipe piles) in sandy soil area. Furthermore, when compared with traditional pipe piles, H-shaped steel piles requires less materials and can create greater economic value, making them an excellent choice for the foundation of desert photovoltaic bracket foundations. The research results in this paper have reference for engineering applications.

This study targets at asymmetric deformation of narrow coal pillar in gob-side entry driving.We put forward the bidirectional reinforcement of narrow pillar with opposite-crossing anchor cable.Specifically, we designed two types of anchor cable structure: the byelongation type and the expansion lock type, and carried out the pull-out test of opposite-crossing anchor cable, the test shows that both anchor cable structures could meet the tensile requirements.We conducted comparative analysis on the morphology of anchor cable failure, construction convenience and the economic aspect of material selection, where the expansion lock type crossed anchor was selected for narrow coal pillar bidirectional reinforcement.Furthermore, we investigated the bearing deformation patterns of coal pillars and the stress characteristics of anchor cables under different reinforcement methods through similar model tests and numerical simulation.Results show a 96.04% increase of peak load in the specimen reinforced by the double-row tight opposite-crossing anchor cable compared with that of the not reinforced specimen, and higher stability of the narrow pillar reinforced by the double-row tight opposite-crossing anchor cable as the rows of the anchor cable increases in number.The expansion lock anchor type crossed cable improved the energy storage and the critical failure point before the coal pillar was destroyed.Finally, the engineering test of expansive lock type crossed anchor cable to reinforcing narrow coal pillar was carried out in the transportation roadway of 123 lower 04 working face of Jining No.3 Coal Mine.The monitoring show that the anchoring force of the anchor cable exceeded 220kN, with 70& reduction of the coal pillar in the reinforcement area and good overall stability of the narrow coal pillar.It proves the feasibility of the bidirectional reinforcement technology of narrow pillar and provides new technical way for gob-side entry driving.

Modern forestry relies on an extensive network of well-maintained forest roads. However, the trafficability of forest roads can be limited by poor construction or by insufficient load-bearing capacity caused by, for example, weather conditions. In all forestry operations, the forest roads should be able to support heavy vehicles during the transport of roundwood and harvesting machinery, so logistics must be carefully planned to ensure good road trafficability. To facilitate this planning, it is necessary to know the various characteristics of the forest road in terms of its width, structure and load-bearing capacity. Obtaining such information using remote sensing data would be beneficial. In this study, we used airborne laser scanning (ALS) data to assess the width of the roadway on forest roads. We developed several algorithms that were used to assess roadway width based on the cross-sectional data (derived with ALS) of the roads in 8-m long segments. The ALS echoes within the segments were classified into 20 cm wide strips which the algorithms then analyzed in a stepwise manner. Both height and intensity information from the ALS data were utilized. The algorithm results were then used as predictors in linear models to predict the roadway width. The main focus was on the road level, i.e., aggregated values from 25 different roads were used in model fitting. In terms of root mean square error (RMSE) values, accuracies of approximately 20–30 cm (or 7–10 %) were obtained for the predicted roadway widths with a separate validation data. This level of accuracy can be considered adequate given the characteristics of the ALS data used in the modelling. The results indicate that the presented approach has potential for practical applications to predict the width attributes of forest roads.

With the great development of the construction industry, prefabricated building components have been greatly developed. To study the compressive performance of the new wallboard, the axial compression performance test of six full-scale new lattice wallboards was carried out in this paper. The failure mode, axial pressure-displacement relationship curve, axial compression bearing capacity, and axial pressure-strain relationship of the wallboard were obtained through the experiments. This reveals the influence of the thickness of the concrete surface and the number of ribs on the performance of the wallboard. The test results show that the ultimate bearing capacity of the specimen increases with the increase of the thickness of the concrete surface layer with the same number of ribs. Specimen DW -30 increased by 4% over DW -20 and DW -50 increased by 41.6% over DW -30. The ultimate bearing capacity of the three-ribbed specimens was higher than that of the two-ribbed specimens for the same concrete face thickness, about 1.11 times that of the two-ribbed specimens. The concrete facing thickness and the number of ribs have a restraining effect on the deformation of the wallboard. Additionally, the calculation formula of axial bearing capacity of type latticed wallboard considering the influence of eccentric compression was proposed, which can provide a reference for engineering calculation.

The ultimate bearing capacity of stone columns is very important in the design of soil improvement. The bulging failure mechanism is the most common failure mechanism reported. However, it depends on the surrounding soil at the site, necessitating a site-specific study of single-stone column bearing capacity. The current paper presents the full-scale plate load test of the single stone column in the Long Son Petrochemical Project, Vietnam in order to verify the bearing capacity of single stone column. A single stone column of 800 mm diameter was installed at the site by vibroflot. An 800 m circle full-scale plate test was carried out on site. The stone properties followed the Vietnamese standard TCVN 7572. The settlement result of the plate load test verifies the single stone column bearing capacity of 882.5 kPa.

Composite slabs, consisting of a precast plank and a cast-in-situ concrete topping, are the most commonly used horizontal structural components in prefabricated buildings. In order to solve the problem that the precast plank of composite slab is easy to crack and a lot of vertical supports are needed in its construction, this study proposes a new type of composite slab with a joint. The precast plank of this novel composite slab is fully prefabricated in the midspan area, and concrete is poured on-site only at the surrounding joints. In this paper, the bending performance of three composite slabs with a joint in different shapes of concrete topping and one cast-in-situ slab was investigated. The test results showed that the novel composite slabs with a joint in T-shape and trapezoidal concrete topping had similar properties as the cast-in-situ slab, including bearing capacity and cracking load, which can meet practical requirement. The use of bent-up steel bars and roughening of the interface between the precast plank and topping concrete can ensure effective transmission of internal forces at joint. The bearing capacity of the composite slabs with a joint in T-shape and trapezoidal concrete topping was evaluated using the formula in GB50010–2010, and the experimental values were 1.06 and 1.1 times the theoretical values, respectively, which provides a foundation for the design of two types of composite slabs with a joint. Meanwhile, based on the FEA software ABAQUS, numerical simulation was conducted on the composite slab with a joint in T-shaped concrete topping. The numerical finding exhibit close agreement with experimental results in terms of load-midspan deflection curve and the crack distribution.

This large-scale test investigated the behavior of a pavement structure composed of a crushed rock base underlain by a soft clay subgrade reinforced with a triaxial geogrid under static loading. The fully instrumented pavement model included a 0.8-m-thick soft clay layer and a 0.2-m-thick crushed rock layer. A triaxial geogrid, Triax TX150, was installed at the interface between the subgrade and base layers and the mid-depth of the crushed rock base. Both unreinforced and reinforced pavement models were prepared in a square steel mold of 1.5 m width and 1.2 m height. Plate load tests were conducted according to ASTM standards. The results revealed that the number of geogrid layers and their locations influenced the reinforced pavement’s ultimate bearing capacity and failure mechanisms. Two-layer reinforcement (between the crushed rock and soft clay layers and in the middle of the crushed rock layer) provided the maximum bearing capacity, with an improvement factor of 1.63 compared to that of the unreinforced pavement, because the triaxial geogrids changed the failure mode of the unreinforced pavement from punching failure in the crushed rock and local shear failure in the soft clay to only punching failure in the crushed rock. Thus, triaxial geogrids are suggested for enhancing the performance of pavements on soft clay subgrades.

Port pavements often experience damage, such as differential settlements and cracks, owing to soft ground and heavy equipment operations. This study focuses on developing and applying port blocks in two configurations within a port to assess its applicability based on deflection and settlement characteristics. Falling weight deflectometer (FWD) tests were carried out on both asphalt and block pavements to measure deflection and bearing capacity. Results indicate that the block pavement with a cement-treated base exhibited improved bearing capacity and settlement performance during port operations compared to asphalt pavement. This improvement was evident in the relative deflection and relative bearing ratios, where the cement-treated base demonstrated enhanced bearing capacity over asphalt. Light detection and ranging (LiDAR) measurements revealed several settlements in the crushed-stone base due to surface loads post-construction. While both relative deflection and relative bearing ratios indicated settlement tendencies, the latter proved more consistent with the settlements. The settlements were generally less than 5 cm with the superior bearing capacity block pavement presents itself as a viable pavement for various port settings.

Fiber Reinforced Polymer (FRP) material is advocated for use in bridge structures to solve the corrosion and degradation problem of conventional steel reinforcements, thereby improving its durability and service life. Also, compared with ordinary concrete, self-compacting concrete (SCC) mixed with abundant industrial waste materials is expected to achieve sustainable development of concrete infrastructure. However, the research examining the performance of FRP reinforced SCC slabs in a real bridge is rather limited. This paper describes the application of basalt-FRP (BFRP) in a real bridge deck slab cast with low energy SCC. Since few studies have considered arching action on a real bridge deck slab, this paper aims at extending previous laboratory research using glass-FRP (GFRP) and BFRP reinforcement in in-plane restrained slabs to real bridge deck slabs. This study primarily investigates the serviceability behavior of real bridge deck slabs and utilizes the arching theory to predict their ultimate bearing capacity. The bearing capacities of real bridge deck slabs have been compared with the current specification requirements and the predictions considering arching theory. The test results indicate that a significantly low percentage of FRP reinforcement is possible in real bridge deck slabs due to the advantageous arching action.

The purpose of this paper was to determine the specifics of the placement of dumps during the development of upland deposits and to develop recommendations to improve quality management in industrial and manufacturing engineering during the development of mineral resource deposits. As a result of the performed research, it was proved that the placement of dumps during the development of upland deposits requires more calculations for planning and ensuring stability than for dumps located on a horizontal surface. Assessment of the stability of dumps on the slope is a key component of ensuring the safety of dumps. One of the main factors affecting the stability of dumps on an inclined base is the bearing capacity of the base. When planning the area for the dump, the bearing capacity and strength of the base rocks are calculated. The article describes a method for determining the loading of the dump depending on the bearing capacity of the base of the dump of overburden rocks. The features of the placement of overburden dumps during the development of upland deposits are revealed, taking into account the planning of the base for the dump, depending on the strength characteristics of the base and the slope angle. The theoretical significance of the results obtained is due to their rethinking of the essence of the development of mineral resource deposits from the position of quality management in industrial and manufacturing engineering. The practical significance of the authors’ developments is that the authors’ methodology of determining the load of the dump depending on the carrying capacity of the base dump of overburden rocks will allow improving quality management in industrial and manufacturing engineering of the development of mineral resource deposits.

The problem considered in this short note is the limit load determination of a vertical rock slope. The classical limit theorem is employed with the use of adaptive finite elements and nonlinear programming to determine upper and lower bound limit loads of a Hoek-Brown vertical rock slope. The objective function of the mathematical programming problem is such as to optimize a boundary load, which is known as the limit load, resembling the ultimate bearing capacity of a strip footing. While focusing on the vertical slope, parametric studies are carried out for several dimensionless ratios such as the dimensionless footing distance ratio, the dimensionless height ratio, and the dimensionless rock strength ratio. A comprehensive set of design charts is presented, and failure envelopes shown with the results explained in terms of three identified failure mechanisms, i.e. the face, the toe, and the Prandtl-type failures. These novel results can be used with great confidence in design practice, in particularly noting that the current industry-based design procedures for the presented problem are rarely found.

The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills. However, reusing waste tires can address this issue when waste tires are used in geotechnical applications. To determine the viability of this approach, laboratory-scale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred (STS) mixtures with shredded waste tire contents of 5%–15% by weight and three different widths of shreds. The investigation focused on analyzing the thickness of layers composed of STS mixtures, the soil cap, and the impact of geogrids on bearing capacity. The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity. In addition, the optimal shred content and size were found to be 10% by weight and 2 cm × 10 cm, respectively. Furthermore, for a given tire shred width, a particular length provides the largest bearing capacity. The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio (CBR) tests. The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.

The effect of vertical vibrational loads on the bearing capacity of a foundation resting on salt-encrusted flat soil improved by cement addition was experimentally examined by conducting a physical model. The vibration foundation model resting on the finite dimensions of cemented sabkha was first subjected to incremental vertical monotonic loads to evaluate the bearing capacity for different subsoil conditions; the bearing capacity was calculated from the load–settlement curves. The cemented sabkha overlies the saturated sabkha soil. The influence of the vertical vibrational load for each increment in the vertical monotonic load on the settlement was studied, and a modified load–settlement curve was introduced. For a foundation with no large deformation or liquefaction due to vibrational loads, the vibrational loads insignificantly influence the bearing capacity of the foundation. With increasing frequency, the initial stiffness decreases, resulting in an increase in the settlement. The influence of the cement content and thickness of cemented sabkha on decreasing the foundation’s settlement decrease with increasing monotonic loads and operating frequency.

Abstract Beam-like members sustaining the combined action of transverse load and membrane force exhibit a special load response to progressive deflection. A theoretical model is therefore developed to depict the resistance behaviours of clamped reinforced concrete (RC) beams observed in tests. The support-induced membrane effects are simulated by a longitudinal spring and a rotational spring. The load responses to progressive deflection are obtained using the membrane approach, and the prediction accuracies of proposed method are validated by a series of four-point bending tests on hybrid fibre reinforced-lightweight aggregate concrete (HFR-LWC) beam. It is illustrated that the bearing capacities of clamped HFR-LWC beam are significantly enhanced by the membrane effect. Ultimate load of the clamped beam ranges from 64.0 to 184.0 kN, and the larger bearing capacity compared with simply supported beam is obtained. An ultimate load of 1.85 to 5.31 times the yield line value is achieved, and thereby, the ultimate resistance of the clamped beam might be seriously underestimated using yield line approach. A strong support constraint is beneficial for increasing the load-carrying capacity of clamped HFR-LWC beam, although the large longitudinal restraint stiffness would inevitably gives rise to brittle failure. The relative errors between predicted load and measured value are less than 7.23%, indicating that the presented model is a promising tool to estimate the ultimate load of clamped beam-like member.

Abstract The design process for pile foundations necessitates meticulous deliberation of the calculation pertaining to the bearing capacity of the piles. The primary objective of this work was to investigate the potential use of Coot bird optimization ( $${\text{CBO}}$$ CBO ) techniques in predicting the load-bearing capacity of concrete-driven piles. Despite the availability of several suggested models, the investigation of Coot bird optimization ( $${\text{CBO}}$$ CBO ) for estimating the pile-carrying capacity has been somewhat neglected in this research. This work presents and validates a unique approach that combines the Coot bird optimization ( $${\text{CBO}}$$ CBO ) model with the Multi-layered perceptron ( $${\text{MLP}}$$ MLP ) neural network and adaptive neuro-fuzzy inference system ( $${\text{ANFIS}}$$ ANFIS ). The findings of 472 different driven pile static load tests were put in a database. The proposed framework's building, validation, and testing stages were each accomplished utilizing the training set (70%), validation set (15%), and testing set (15%) of the dataset, respectively. According to the findings, $${{\text{MLP}}}_{{\text{CBO}}}$$ MLP CBO and $${{\text{ANFIS}}}_{{\text{CBO}}}$$ ANFIS CBO both offer remarkable possibilities for accurately predicting the pile-bearing capacity of a given structure. The $${R}^{2}$$ R 2 values for $${{\text{ANFIS}}}_{{\text{CBO}}}$$ ANFIS CBO during the training stage were 0.9874, while during the validating stage, they were 0.9785, and during the testing stage they were 0.987. After considering various kinds of performance studies and contrasting them with existing literature, it has been concluded that the $${{\text{ANFIS}}}_{{\text{CBO}}}$$ ANFIS CBO model provides a more appropriate calculation of the bearing capacity of concrete-driven piles.

Bucket foundations are circular surface foundations with thin skirts around the circumference. They have been successfully installed using economical suction or vibratory methods. Large-diameter buckets, up to 22 m, have been successfully deployed. In offshore wind power applications, bucket foundations are commonly configured in a tripod arrangement for fixed foundation wind turbines. While bucket foundations may be subjected to complex conditions of combined loading, this study presents an in-depth focus on a single loading mode: vertical compression. This study presents a finite element investigation of the performance and vertical load capacity of skirt foundations installed in the sand and subjected to vertical load passing through the bucket center. To take advantage of symmetry for problem geometry and applied load, an extensive parametric study was performed in this research utilizing an axisymmetric (two-dimensional) finite-element analysis employing the non-associated flow rule of the Mohr-Coulomb soil model. Comparisons to previously published 3D FE and experimental studies showed good agreement. The results showed that the pure vertical capacity of the bucket foundation significantly depends on skirt diameter D, aspect depth ratio (L/D), and relative density Dr. This research introduced simple design charts relating the vertical bearing capacity of skirted foundations to aspect ratio, diameter, and relative density.

Slip-form concrete (JPCP) has a number of years of good performance experience. An alternative to slip-form concrete is roller-compacted concrete (RCC). The RCC mixture has a significantly larger number of fine aggregates, which leads the concrete mix to be non-slip and compacted by rollers. RCC has the strength and performance of conventional concrete or even higher. Due to all the advantages, the use of RCC pavement in industrial areas and low-volume rural roads is very beneficial. Experimental test section of RCC pavement structure with cement and special additives stabilized base (CTB) was installed on local road No. 130 in Lithuania, which was reconstructed in 2021. The main objective of this study is to learn about the environmental impact on the pavement structure. To reach our aim at the stage of reconstruction of the local road temperature, humidity sensors and a strain gauge were installed under the RCC layer and CTB. During the lifetime of pavement structure temperature and humidity data were collected daily and bearing capacity was measured during spring thaw. In addition, an artificial wheel load simulation using a falling weight deflectometer was performed at the location of the installed strain gauge to analyse deflections and to calculate stresses under RCC layer. The stresses under the RCC layer calculated from the strain gauge were also compared with the theoretical stress calculated at the design stage of the pavement structure to learn more about performance of the pavement structure. The results showed that slight changes in humidity at the bottom of the CTB had no significant influence on the deformations at the bottom of the RCC layer. Comparison of stresses under RCC layer showed that stresses calculated from strain gauge were 1.80 times lower than those calculated theoretically.

This study aims to explore the significant impact of soil fabric anisotropy on the ultimate bearing capacity of eccentrically and obliquely loaded shallow foundations overlying a geosynthetic-reinforced granular deposit. For this purpose, the well-established lower bound theorems of limit analysis (LA) in conjunction with the finite elements (FE) formulations and second-order cone programming (SOCP) are exploited to perform the bearing capacity estimations. The consideration of the soil mass’s inherently anisotropic response in the granular layer involves the utilization of distinct internal friction angles in various directions. The lower bound FELA framework adopted in this study incorporates both the pull-out and tensile mechanisms of failure in the reinforcement layer. The marked contribution of soil inherent anisotropy to the impacts of ultimate tensile strength (Tu) and embedment depth (u) of the geosynthetic reinforcement on the failure mechanism, bearing capacity ratio (BCR), and failure envelope of the overlying obliquely/eccentrically strip footing is rigorously examined and discussed. It is generally concluded that for a given embedment depth, failure envelopes of the surface footing in both V-H and V-M planes shrink appreciably with the increase in the soil anisotropy ratio as well as the decrease in the geosynthetic ultimate tensile strength. Moreover, the influence of soil inherent anisotropy on the overall bearing capacity of shallow foundations is more evident in the case of using strong reinforcement compared to the weak geosynthetic. The findings of this investigation demonstrate that overlooking the soil inherently anisotropic behaviour in the numerical analysis of shallow foundations would give rise to undesirable non-conservative and precarious designs.

Shallow and inclined skirted foundations on 30% sandy soil were examined in the experiment program. The study examined the effects of positive and negative eccentric-inclined loading on foundations. Experimental testing was done in a 600 × 600 mm box with a 50 x 50 mm square footing with a 10 mm thickness. The skirt angles were 10°, 20°, and 30°, and the skirt depth was Ds was 0.5 B. Results showed that using skirts significantly increases load-bearing capacity and decreases tilting. Tilting reduces with a skirt, and skirt inclination (alpha) increases with similar loads. Inclined skirts decrease tilt by (2.3% to 0.66%) at e was 0.15 B, load angle (beta) was 15°, and alpha was 30° in the negative case. Tilting increases with eccentricity. As load inclination grows, unskirted and skirted foundations slide and rotate. For the positive case, the tilting decreases from 10% to 2% with e was 0.15 B, loading angle (beta) was 15°, and alpha was 30° with an inclination skirt. The amount of horizontal displacement of the skirted foundation is more than that of the unskirted foundation when comparing the failure load for the unskirted foundation with the same load for the skirted foundation. Loading a foundation without a skirt causes significant settlement and little horizontal displacement. Increasing the load angle is effective since it greatly affects horizontal displacement. In some situations, such as a negative eccentric-inclined load with Ds was 0.5 B, beta was 15, and e was 0.05 B, the influence of the loading angle may be decreased once failures with eccentricity. When eccentricity increases while the load angle (beta) remains constant, the horizontal displacement of a negative eccentric-inclined load reduces.

For projects such as airports and road paving, an appropriate foundation must be developed in Sabkha soil, which requires a trustworthy assessment of soil-bearing capacity. When heavy traffic is expected to result in substantial wheel loads throughout pavement construction and maintenance, the plate load test helps solve these issues with subgrade and sub-base layer design. This work aims to investigate and assess the geotechnical behavior regarding soil strata from one area in southern Iraq: Sabkha. Conversely, a comparison is made between subgrade response modulus and soil-bearing capacity determined by field plate load tests and traditional laboratory investigations. The data demonstrated that the values related to Ks in the consolidation test rose as a ratio of pre-consolidation pressure of 45% and dramatically dropped with an increase in applied stress that is vertically applied below pre-consolidation stress. Furthermore, PLT data demonstrated that when pressure was applied, the modulus of the subgrade reaction did not follow a regular pattern. At the beginning of the loaded stage, after the pre-consolidation stress, Ks values at testing points 2 and 3 were high. After that, Ks abruptly decreased, particularly when the applied pressure surpassed the pre-consolidation stress before being constant again. A detailed discussion is given on the effects of stress distribution and test conditions on the elasticity stress curve's shape and the subgrade reaction modulus.

This study presents a comprehensive examination of the effects of quicklime (QL) addition on the stabilization of two distinct clayey soils with high (CH) and low plasticity (CL-tuff). The results showed that incorporating QL into the soils substantially improves their stabilization characteristics. Specifically, the addition of QL results in a notable decrease in the final water content of both soils, as shown by a reduction from 23.04 to 19.06% in CH and from 18.07 to 17.1% in CL-tuff at 4% QL addition. Furthermore, this study reveals a transformation in the plasticity properties of soils. Liquid Limit (LL) and Plasticity Index (PI) were reduced, with CH-tuff exhibiting a significant decrease in PI from 48 to 12 and an increase in Plastic Limit (PL) from 21.8 to 55 at 4% QL. CL-tuff also showed reduced plasticity, with PI decreasing to 8.33 at 4% QL. Additionally, the Immediate Bearing Index (IBI) was improved for both soil samples, indicating improved load-bearing capacities. For CH samples, IBI improved from 6.37 to 11.99 at 4% QL addition, while for CL-tuff, it increased dramatically from 4.5 to 23.6 for the same QL percentage. The findings underscore the effectiveness of QL in improving soil properties crucial for chemical stabilization, providing evidence that QL addition can be a key technique in soil stabilization, especially for soils with high plasticity or those requiring increased bearing strength.

Compared with natural wood, laminated veneer lumber has the characteristics of high strength, flexible specifications, excellent stability, and good economy. In order to study the bearing capacity of LVL trusses, the mechanical properties of LVL materials were tested. The static load test was carried out by using 3 pieces of LVL truss, and the load-deflection relationship, load-strain relationship, bearing capacity and failure mode of LVL trusses were studied. Based on the simplified joint analysis method, the metal plate connection and bolted truss were analyzed, and the bearing capacity calculation formula was developed. The results show that the upper chord instability is the main failure mode for large-span light LVL truss. A simplified formula for bearing capacity of LVL truss was proposed, and the predicted results were in good agreement with the experimental results. Finally, an application example of LVL truss engineering design and construction is briefly introduced. The research can provide technical support for the promotion and application of LVL truss of lightweight poplar wood.

This study proposes a framework to evaluate the performance of borehole arrangements for the design of rectangular shallow foundation systems under spatially variable soil conditions. Performance measures are introduced to quantify, for a fixed foundation layout and given soil sounding locations, the variability level of the foundation system bearing capacities in terms of their mean values and standard deviations. To estimate these measures, the recently proposed random failure mechanism method (RFMM) has been adopted and extended to consider any arrangement of rectangular foundations and boreholes. Hence, three-dimensional bearing capacity estimation under spatially variable soil can be efficiently performed. Several numerical examples are presented to illustrate the applicability of the proposed framework, including diverse foundation arrangements and different soil correlation structures. Overall, the proposed framework represents a potentially useful tool to support the design of geotechnical site investigation programs, especially in situations where very limited prior knowledge about the soil properties is available.

This study investigates the ultimate bearing capacity of a rigid strip footing on a sandy slope using the Rigid Plastic Finite Element Method (RPFEM). To accurately represent a wide range of frictional conditions at the footing roughness, a new interface element was introduced, capable of accommodating both perfectly rough and perfectly smooth conditions. A new constitutive equation is introduced to model these interface elements, which had a significant influence on the failure mode of the strip footing. Moreover, the study focuses on assessing critical parameters, including the internal friction angle of the sandy ground, as well as slope geometry parameters (slope angle b, edge distance L, and slope height H). The RPFEM results illustrate that increasing the edge distance positively influences the bearing capacity, while a higher slope angle exerts a negative effect. Notably, variations in slope height produce consistent outcomes, regardless of the frictional conditions.

Compared with natural wood, laminated veneer lumber has the characteristics of high strength, flexible specifications, excellent stability, and good economy. In order to study the bearing capacity of LVL trusses, the mechanical properties of LVL materials were tested. The static load test was carried out by using 3 pieces of LVL truss, and the load-deflection relationship, load-strain relationship, bearing capacity and failure mode of LVL trusses were studied. Based on the simplified joint analysis method, the metal plate connection and bolted truss were analyzed, and the bearing capacity calculation formula was developed. The results show that the upper chord instability is the main failure mode for large-span light LVL truss. A simplified formula for bearing capacity of LVL truss was proposed, and the predicted results were in good agreement with the experimental results. Finally, an application example of LVL truss engineering design and construction is briefly introduced. The research can provide technical support for the promotion and application of LVL truss of lightweight poplar wood.

In this investigation, the bearing capacity solution of a strip footing in anisotropic clay under inclined and eccentric load is analyzed using the numerical simulation model. The lower and upper bound finite element limit analysis (FELA) approaches are utilized to establish precise modeling and derive the numerical outcomes of a strip footing's bearing capacity. All analyses use effective automated adaptive meshes with three iteration stages to enhance the accuracy of the outcomes. The parametric analysis is performed to examine the influence of four dimensionless parameters which are taken into account in this study, namely the anisotropic strength ratio, the dimensionless eccentricity, the load inclination angle, and the adhesion factor to the bearing capacity factor. Furthermore, a new model has been proposed to predict the bearing capacity factor for the calculation of the undrained bearing capacity for footings resting on an anisotropic clay using an advanced data-driven method (MOGA-EPR). The new model takes into account the anisotropy, eccentricity, and inclination of the applied load and could be used with confidence in routine designs of shallow foundations in undrained conditions with the consideration of the anisotropic strengths of clays.

Abstract Bearing capacity of reinforced footing clearly depends on the characteristics of interface between geosynthetic and soil. A suitable solution for increasing the bearing capacity is to treat the geotextile surface by various additives. This study reported the results of plate load test on square model footing resting on reinforced sand with and without treated geotextiles to survey the effects of the treatment of geotextile on settlement and bearing capacity. The treated geotextiles were made using additives onto the surface, with a layer of sand located on the top. Geotextile sides were treated in the same way. Different additives including the lime, cement, emulsion, and the effect of the number of layers were considered. The bearing capacity ratio values (BCR), improvement ratio values (IR) and variation of load-settlement ratio obtained from the treated models were presented. The results showed that the treatment of geotextile has a great effect on the behavior of reinforced sand and thus bearing capacity. Also, the test results indicated that lime-treated geotextiles provided better improvement than other additives. The maximum improvement in the bearing capacity of square footing supported on treated geotextiles was found to be 75% compared with the pristine geotextiles.

Abstract In recent years, robots with leg mechanisms have received considerable attention as high-running planetary exploration rovers. Rovers undertaking planetary exploration require outstanding running performance to travel on loose ground on which they mostly slip and hardly move forward. The movement of the rover easily deforms the surface of loose ground. This problem can be solved by increasing the bearing capacity. The bearing capacity, the resistance force exerted on the rover legs when they make contact with the ground, needs to be sufficiently large to prevent legged rovers from slipping on loose ground. The bearing capacity can be increased by compaction of the ground by imparting vibrations. This study investigates the relationship between the bearing capacity in the horizontal direction and vibration parameters because this relationship offers valuable information for improving the running performance of legged rovers. First, we investigated the effect of changing the vibration parameters on the bearing capacity. Our experimental results show that the bearing capacity is related to vibration acceleration. These results suggest that the bearing capacity can be estimated from the vibration acceleration. Next, the frequency and amplitude were compared as vibration parameters to devise an efficient method for increasing the bearing capacity. The results of these experiments showed that high-amplitude vibrations increase the bearing capacity to a greater extent than high-frequency vibrations. The reason is that high-amplitude vibrations generate larger additional vibrations by the collision between the rod and the ground than high-frequency vibrations. This knowledge is valuable for selecting a suitable vibration that can efficiently increase the bearing capacity. This study suggests a method of facilitating further planetary exploration using legged rovers.

Kediri has been named the Most Sustainable City. To support this, Kadiri University also contributed by building lecture buildings. In its implementation, there is a difference in the depth of the foundation from the initial plan. This causes the need for evaluation to ensure the safety of the building structure. This research aims to identify (Cone Penetration Test) CPT distances, depth differences, negative skin friction, settlement, and empirical bearing capacity calculations on the safety of building structures on sandy soil. The direct observation method was used to obtain data. The analysis includes a comparison of depth, negative skin friction values, settlement, and bearing capacity. The research results show that the average CPT distance is 18.22 m, which can result in inaccurate CPT data because differences in soil structure can occur. A depth difference of 22% from the plan can be considered safe for the structure. This is validated by a field settlement of 2 mm lower than the maximum settlement limit and a Negative skin friction value of 0, indicating no additional settlement. These parameters indicate that the structure is safe. The modified Meyerhoff and Trofimankove methods are suitable for planning foundations with sandy soil because they can meet the load received. This research can add empirical evidence in evaluating structural safety for different depths of foundation planning and implementation in sandy soil-based projects, as well as reducing the potential risk of structural failure in the long term.

The results of experimental studies of deformation problems in pipeconcrete specimens with small cross sections are provided and analyzed. The stress-strain state of a steel pipe and a pipe filled with concrete is studied and compared. Experimental determination of the dependencies between axial load and deformations of pipe-concrete and steel bars, as well as evaluation of concrete’s and steel pipe’s contribution to the total load-bearing capacity of the composite section are provided. Tests were carried out for short pipe-concrete specimens with the pipe dimensions equal to 60x2, 76x3 and 102x3.5, as well as for hollow steel pipes with the corresponding dimensions. The diagrams of deformation were obtained basing on the experimental results. The deformation of the pipe-concrete element under central compression occurs in proportion to the deformation of a hollow steel element with the same diameter, that made it possible to evaluate the contribution of concrete to the work of the pipe-concrete cross-section, which turned out to be constant at each stage of deformation. A methodology has been proposed that enables to describe analytically the deformability of pipe-concrete elements under axial compression by means of the analytical model based on the experimental data.

The primary objective in foundation design is to ensure that the foundation exhibits satisfactory behavior under regulatory loading conditions while addressing critical safety concerns. This study aims to investigate the impact of parameter uncertainties in prediction models for bearing capacity and settlement of shallow and deep foundations on resulting failure probabilities using various approximation methods. Recognizing the complexity of reliability studies, this research explores the possibility of not probabilizing all variables and simplifying calculations for future applications. Additionally, it aims to assess the effectiveness of commonly used approximation methods in geotechnical engineering for estimating failure probabilities. The study's findings would enhance foundation reliability indices and decrease the probability of failure. The parametric study has enabled us to identify the variables that are most sensitive to changes in their coefficient of variation. The influence of model selection on foundation reliability is emphasized, and a critical evaluation of model bias is crucial for reliability analysis. It is evident that conservative models may shift subsequently calculated failure probabilities by inaccurately assigning situations from the safe domain to the failure domain due to inherent conservatism.

The Geographic Information System (GIS) is one of the modern database software which is used to collect, analyze, display, processing and produce geographic information maps for a specific objective. In addition, a statistical analysis can be generated within GIS on specific data to produce quantitative results. In this study, the GIS utilized to produce thematic maps showing the variation of bearing capacity of shallow foundation in Al-Basrah province soil. All the features mentioned above illustrate the importance of GIS exploring more valuable results such as the bearing capacity of shallow foundation from the results of standard penetration tests (SPT) conducted in Al-Basrah province soil. The total number of boreholes drilled was 135 distributed irregularly in the study area. In each borehole, three SPTs were performed at depths of 1.5, 6, and 9.5 m measured from the existing ground level (EGL). The results of the study can be summarized by the production of thematic maps showing the variation of the bearing capacity of the soil over the whole area of Al-Basrah city correlated with several depths. These maps can be used by different local authorities to predict soil bearing capacity and choose a suitable type of foundation. In addition, it can be utilized to assess the foundations of existing and irregularly constructed buildings and to assess the extent of the risks of failure and collapse.

Abstract In recent years, constructing natural aggregates as a base layer for the roads has increased. Natural resources will run out as long as human consumption of them continues. Recycled concrete aggregate (RC) has thus emerged as a substitute material for the building of road base layers. Additionally, RC can be utilized to create interior city highways. The base layer for roads must have sufficient strength to support the working load on the pavement surface without damage deforming. As a result, the focus of this paper is on enhancing the structural performance of sandy soil reinforced with various RC percentages. The three key factors are relative soil density (Dr = 83 and 97%), recycled concrete aggregate reinforcing levels (RC = 0,5,10,15,20,25,30,40,50 and 100%), and reinforcement layer thickness (Rd = 0.0B, 0.5B, B, and 2B where B is the footing model width). Numerous laboratory experiments were conducted in order to examine the impact of important parameters on the properties of the mixtures. The plate bearing tests were carried out using a footing model (250 × 250 mm) inside a tank (1500 × 1500x1000 mm) to ascertain the stress–strain response, bearing capacity ratio (BCR), ultimate bearing capacity, and modulus of elasticity of the tested mixtures. It is clear that raising the RC has no effect on the diameters of the grains. It was found that as RC increased, the mixture's bulk density increased but specific gravity decreased. Maximum dry density rose as RC rose, whereas water content fell. It was noted that BCR unquestionably increased as RC increased for all RC levels and all values of settlement ratios. The appropriate reinforcing layer thickness is suggested to be no more than 2B. As the RC concentration in the sand and Rd increased, the difference between two pressure-settlement curves of densities 83% and 97% significantly decreased. Furthermore, when RC reaches 50%, two curves are roughly comparable. At RC = 50%, it is advised that the relative density of 83% is sufficient to produce the same behavior as the relative density of 97%. It was found that as RC and Rd grew, the tested mixtures' ultimate bearing capacity and elasticity modulus increased as well. A novel proposed formulas are developed to compute bearing capacity ratio, ultimate bearing capacity, and elasticity modulus of the tested mixtures taking into account the influence of RC, reinforcement layer depth, settlement ratio, and the relative density, and its results agree with the experimental results.

To investigate the axial compression behavior of composite columns with high-strength concrete-filled steel tube flanges and honeycombed steel web (STHHC) under load during freeze–thaw cycles, 48 full-scale composite column specimens were designed with different parameters: the restraint effect coefficient (ξ), concrete strength (fcu), number of freeze–thaw cycles (nd), slenderness ratio (λ), space–height ratio (s/hw), and hole–height ratio (d/hw). The finite element models of STHHC composite columns were simulated using ABAQUS finite element software (Version: 2021). The modeling method’s rationality was verified by comparing simulation results with experimental outcomes. Based on the finite element model, a parametric analysis of the composite columns under freeze–thaw cycles was conducted, analyzing their failure modes and load-bearing processes. The results indicate that the bearing capacity of the STHHC increased with increases in ξ and fcu, and decreased with a rise in λ. In contrast, the influence of s/hw and d/hw on the ultimate bearing capacity of the composite columns was relatively minor. An equation for calculating the axial bearing capacity of the STHHC composite columns under freeze–thaw cycles was derived using statistical regression methods and considering the impact of different parameters on the axial compressive performance of the composite columns, laying the foundation for the promotion and application of this type of composite column in practical engineering projects.

In saline environments, it is difficult for reinforced concrete structures to meet normal durability requirements, which in turn affects the mechanical properties of the members. In this context, this paper proposes a reinforcement method that involves wrapping corroded reinforced concrete columns with CFRP (carbon fiber reinforced polymer) cloth. By conducting axial compression tests on four specimens, key mechanical performance indicators such as failure mode, ductility, and bearing capacity during the entire stress process of the specimens were analyzed, revealing the failure mechanism of CFRP-confined corroded reinforced concrete columns. A refined finite element model of CFRP-confined corroded reinforced concrete columns was established using ABAQUS software. The influence of key parameters such as the number of CFRP wrapping layers, longitudinal reinforcement corrosion rate, and axial compression ratio on the mechanical properties of the specimens was studied, and the influence of each parameter was determined. Furthermore, a formula for the axial compression bearing capacity of CFRP-confined corroded reinforced concrete columns was proposed. The results indicate that in the presence of corroded steel reinforcement, specimens confined with CFRP undergo substantial lateral constraints during the mid to late stages of loading. This approach effectively alleviates the transverse deformation of the concrete. The specimen demonstrated yield bearing capacities and peak loads of 1441 KN and 1934 KN, respectively, representing a 2.2-fold and 2.5-fold increase compared to the non-reinforced specimen. With the increase in the transverse strain of concrete, CFRP begins to play a restraint role, and a more obvious restraint role in the failure stage of members. It is recommended to apply 1–3 layers of CFRP wrapping for a longitudinal reinforcement corrosion rate of 5%, 3–5 layers for a rate of 10%, and 6–8 layers for an overall corrosion rate of 15%. This paper establishes a theoretical framework for investigating the performance characteristics of such columns and offers technical assistance for practical engineering purposes.

In order to reveal the mechanical behavior of short concrete columns reinforced with hybrid steel and glass FRP bars, 10 specimens were designed for eccentric compression tests. The effect of eccentricity and load–displacement/strain of the specimens was studied. Test results indicate that the damage process and failure mode of these hybrid RC columns was similar to those in the conventional steel-reinforced concrete columns. The mode of failure for all specimens is characterized as large eccentricity compression failure, and the ultimate bearing capacity of the columns decreases with the increase in eccentricity. However, the impact of the varying axial stiffness ratio between GFRP and steel bars on the bearing capacity can be considered negligible. In addition, based on theoretical analysis, two boundary states for distinguishing failure mode and the formulae for calculating ultimate bearing capacity in different failure modes of eccentrically loaded hybrid RC columns are proposed. The computed results agree well with test results.

The suspender is a crucial and vulnerable component of large-span cable bridges, and its service performance inevitably degrades under environmentally corrosive media and traffic load. The long loading area of a large-span bridge provides the possibility for continuous traffic flow braking on the bridge. This study proposes a continuous braking model of traffic flow based on the driver’s emergency braking reaction time and a steel wire degradation model considering the stress distribution characteristics of steel wire bending in the cross-section to analyze the safety of degraded cable components. The degradation process and bearing capacity variation of the cable are accurately quantified, and the reliability of the degraded cable under the action of traffic flow braking is determined. The results show that the traffic flow braking action causes a remarkable bending stress response in the bridge cable that reaches 450 MPa, which is much larger than the normal acting time. Moreover, differences in the bending stress of the cross-sectional steel wire cause significant differences in the fatigue process of the steel wire in different layers of the suspender. The outermost steel wires begin to fail after 12 years, and their service life is considerably different from that of the interlayer wires. The severely degraded steel wires on the outside can easily break under the traffic flow braking action, but they have no noticeable effect on the suspender’s ultimate bearing capacity because of the Daniels effect. The increase in the cable force caused by traffic flow braking and the stress redistribution after the steel wires break have the most evident influence on the reliability of the structure. Due to the effects of traffic flow braking, the timing of suspender maintenance is advanced by 8 years.

In the paper, the eccentric compression behavior of the truss-reinforced cross-shaped concrete-filled steel tubular (CCFST) column is investigated. A total of eighteen CCFST columns were tested under eccentric compression, and the key test variables included the reinforced truss node spacing (s = 140 mm and 200 mm), slenderness ratio (λ = 9.2, 16.6, and 23.1), and eccentricity ratio (η = 0, 0.08, and 0.15). The failure mode, deformation characteristic, stress distribution, strain distribution at the mid-span of the steel tube, and the eccentric compression bearing capacity were assessed. The results show that due to the addition of reinforced truss, the steel plates near the mid-span of eccentrically compressed CCFST columns experienced multi-wave buckling rather than single-wave buckling after the peak load was reduced to 85%, and the failure mode of concrete also changed from single-section to multi-section collapse failure. Comparisons were made with the unstiffened specimen. The ductility coefficient of the stiffened specimen with eccentricity ratios of 0.08–0.15 and node spacings of 140 mm~200 mm increased by 70~83%, approaching that of the multi-cell specimens with an increasing steel ratio of 1.8%. In addition, by comparing the test results with the calculation results of four domestic and international design codes, it was found that the Chinese codes CECS159-2018 and GB50936-2014, and the Eurocode 4 (2004) can be better employed to predict the compression bearing capacity of truss-reinforced CCFST columns.

To address the issue of local buckling in thin-walled steel tube concrete columns, a form of helical stiffening ribs was proposed. Axial compression tests were conducted on five sections of square steel tube concrete column specimens. The research revealed that, compared to ordinary steel tube concrete columns, the axial compression bearing capacity and deformation capacity of steel tube concrete columns with helical rib constraints increased by 18.5% and 7.7%, respectively. The helical ribs effectively enhanced the buckling resistance of the thin-walled steel tube concrete components. The failure pattern of this new type of component was characterized by diagonal cracks in the encased concrete aligning with the direction of the helical ribs, and the buckling of the steel tube walls was concentrated between the helical stiffening ribs. Based on the experiments, an analysis of the buckling performance of thin-walled steel tubes with helical rib constraints was conducted, and this was incorporated into the bearing capacity calculation. The test, simulation, and theoretical calculations showed that the bearing capacity error of the composite columns for each specimen was within 10%. Ultimately, a formula for the critical buckling bearing capacity of the helical rib steel tubes was proposed. The research findings provide a foundation for the engineering application of this new type of component.

Cured-in-place pipe (CIPP) technology is used to repair deformed municipal polyethylene (PE) pipes caused by design flaws, construction issues, or external loads. However, research on CIPP for PE pipes is limited, restricting its broader application. This research focuses on the mechanical response characteristics and failure modes of the composite PE pipe–CIPP liner structure under external loads. Using experimental setups involving comparative test groups with different diameters and wall thickness ratios (DR values, defined as the ratio of the pipe’s outer diameter to its wall thickness), this study evaluates the effects of the liner’s elastic modulus, the bonding effectiveness at the PE pipe–CIPP liner interface, and the initial ovality of the pipes on the load-bearing capacity. The experimental results reveal that CIPP liners substantially enhance the stiffness and load-bearing capacity of PE pipes, with improvements ranging from 200% to nearly 500% depending on the pipe’s DR value. A novel ring stiffness prediction model is also introduced and validated against the experimental data. This model provides a theoretical framework for understanding the complex interactions at the PE pipe–CIPP liner interface and aids in designing more resilient urban drainage systems.

Metro transit construction has begun to develop rapidly in northwest China because of the acceleration of urbanization. Accordingly, metro depots are also regarded as an essential auxiliary facility for stopping, operation, and maintenance of trains. Meanwhile, many commercial buildings are constructed over metro depots to improve the utilization rate of land due to the increasingly scarce urban land resources, known as transit-oriented development (TOD). These buildings have a large covered area and transfer concentrated loads to the bases. Therefore, pile bases under metro depots have the bearing characteristics of undertaking large concentrated loads, while lesser loads are placed on the soil between the adjacent pile bases. Additionally, the main ground in northwest China is collapsible loess, so the collapsibility should also be considered. Based on the above background, this research performed static loading tests with and without immersion in a reduced scale of adjacent pile bases under a metro depot in Xi’an. The remolding process of natural loess could destroy its structure and the anisotropy of natural loess could also affect the test results. Therefore, four kinds of artificial collapsible loess with different mass ratios of barite powder, kaolin, river sand, cement, industrial salt, and calcium oxide were made by the free-drop method. This method could make the artificial loess simulate the structure of natural loess reasonably. Then, the artificial loess with the most similar properties to intact loess was selected by comparison. Finally, static loading tests with this artificial loess were implemented. The results showed that the ultimate bearing capacity was 4.5 kN. At the same time, the axial force decreased along depth, since the pile shaft friction was positive, and the load sharing ratio of pile tip force increased to 0.58 when the load exceeded 4.5 kN in the situation without immersion; the settlement of pile bases increased significantly after immersion, while the negative shaft friction occurred at the depth of −8 cm~−35 cm, and the load sharing ratio of pile tip force reached 0.92.

In this paper, low circumferential reciprocating load foot-scale tests were performed on two nontruncated PHC B 600 130 tubular piles with bearing nodes to characterize the damage process and morphology of the specimens and to investigate the load-carrying performance of the members. The test results reveal that under the action of tensile-bending-shear loading, the bearing concrete in the node area buckles and is damaged, the anchored reinforcement in the node area yields, the constraint is weakened, an articulation point is formed, and the node rotational capacity increases. When the embedment depth increases from 200 mm to 300 mm, the ultimate bearing capacities of the positive and negative nodes increase by 31.04% and 36.16%, respectively. A numerical simulation is used to verify the test results. Considering the four types of piles without truncated nodes, the numerical simulation is used to analyze the node-bearing capacity at different embedment depths. Finally, a preferred node type is proposed as follows: a terminal plate welded anchor bar and pipe pile core-filled longitudinal reinforcement anchored into the bearing node, with a preferred embedment depth of 250 mm.