Evaluation Of Bearing Capacity Research Articles

Evaluating Marine Economic Bearing Capacity: A Network Analysis

Liu, J.; Liu, C.-L.; Zhang, L.-P., and Xu, Y., 2019.Evaluating marine economic bearing capacity: a network analysis. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 597–600. Coconut Creek (Florida), ISSN 0749-0208.Because of the approximate characteristics of network analysis method, it has been used by many researchers to solve the evaluation of marine economic carrying capacity. In this paper, a method of evaluating and contributing factors of marine economic carrying capacity based on network analysis method is proposed. Based on the evaluation and contribution factors of marine economic carrying capacity, the evaluation and contribution factors of marine economic carrying capacity (MEBC), evaluation of bearing capacity (EBC) and control factors of marine economy (CFME) are established. The experimental results show that this method has wide applicability, and it is also a useful exploration for the evaluation of marine economic carrying capacity in the new period.

Measurement-based bearing capacity evaluation for small and medium span bridges

In order to evaluate the bearing capacity of small and medium span bridge at the operational stage, provide a reference for the strategy of reinforcement and maintenance, an evaluation index of bearing capacity based on dead load, live load and structural resistance for small and medium span bridges is constructed. In this paper, the characteristics of vehicle types, vehicle weight, vehicle spacing, wheelbase and axle weight distribution ratio in different lanes are acquired and analyzed by arranging the weight in motion system on a highway. Monte Carlo method is used to obtain general stochastic traffic flow data which conform to the distribution of sample data. Using a program run by Matlab software, the stochastic traffic flow data are applied to sample bridges (simply supported bridge composed of five small box girders of 20 m to 40 m) to get the vehicle load effect. Finally, combined with the dead load of the sample bridge, the bearing capacity evaluation index constructed in this paper is calculated. The results show that under the effect of current traffic volume, the evaluation index of the sample bridge is equivalent to that of the design value suggested in the code, and the safety reserve of the bridge structure is relatively sufficient. Even if the traffic volume is doubled, most of the sample bridges can still meet the daily operational requirements of the bridge.

Predicting California bearing ratio of foundation soil using ultrasonic pulse velocity

The California bearing ratio is a simple load-penetration test for determining the bearing capacity of soil being used as a foundation subgrade, subbase or base course. There are many empirical models to determine the ratio from soil index properties, but most of these are unsatisfactory. The scope of the investigation reported in this paper was to assess the reliability and accuracy of using ultrasonic pulse velocity for reliable estimates of bearing capacity. Ultrasonic pulse velocity is theoretically a much better indicator than other soil properties for evaluating bearing capacity as it is a function of density and elastic modulus and is strongly affected by material strength. A large-scale regression analysis was carried out using experimental data to evaluate the relationship between California bearing ratio and ultrasonic pulse velocity. Attenuation of ultrasonic waves was also investigated for measuring soil gradation, plasticity and compaction properties. It was found that the reliability and accuracy of ultrasonic pulse velocity in assessing the California bearing ratio indirectly seemed to be higher than those of traditional relationships between the ratio and these soil properties. These strong relationships are proposed for engineering projects requiring estimation of the California bearing ratio.

Failure tests and bearing performance of prototype segmental linings of shield tunnel under high water pressure

The occurrence and characteristics of structural failure under high water pressure and the evaluation of structural bearing capacity are of great significance in the rational design of shield tunnels. In this study, the failure process of two types of segmental lining structures used in the Shiziyang Tunnel in China, namely, the straight joint assembly structure (STRS) and staggered joint assembly structure (STGS), are investigated and summarized with prototype tests. The differences in the failure characteristics between the two types of lining structures are observed and analyzed, and two indexes are proposed to evaluate the damage status of the entire structure and local structure by analyzing and interpreting the failure phenomena during the tests. The results show that (1) The failure processes of both STRS and STGS under high water pressure perform as: the accumulation of previous occurred strength damage of segments ultimately leads to the displacement instability failure of structure. However, the difference is that besides the occurrence of large number longitudinal penetrating cracks at segments, there are local crushing and shear cracks occurred at the joints in STRS. (2) The failure processes of STRS and STGS under high water pressure can be divided into three stages: normal deformation stage, strength damage stage, and displacement instability stage. (3) With the proposed two indexes, the failure phenomena and structural bearing capacities at various stages of the failure process can be theoretically analyzed and quantitatively evaluated. The effective stiffness coefficient βe (specifically, βte for STRS and βce for STGS) is recommended to assess the structural bearing status, and the residual bearing capacity coefficient Rbc is suggested to evaluate the residual structural bearing capacity. (4) For STRS, when obvious cracks appear, βte is 0.83 and Rbc is 0.71; when significant deformation occurs, βte is 0.65 and Rbc is 0.52; and when the structure fails, βte is 0.4 and Rbc is 0.35. For STGS, when microcracks appear, βce is 0.67 and Rbc is 0.58; when the structure is significantly deformed, βce is 0.49 and Rbc is 0.43; and when the structure fails, βce is 0.18 and Rbc is 0.27. (5) In the loading process, βe and Rbc of STRS and STGS decrease constantly. For STRS, the two indexes rapidly decline after visible cracks appear, but for STGS, the decreasing amplitude is relatively small.

Bearing capacity of isolated square footing resting on contaminated sandy soil with crude oil

The main objective of this paper is the evaluation of bearing capacity of isolated square footing resting on clean and oil-contaminated sand. The study is aimed at determining the effect of percentage of oil content in sand and the depth of the contaminated sand layer under the footing on the bearing capacity of footing. A series of routine laboratory tests were carried out on sand to obtain the physical, mechanical, and chemical properties. Crude oil is used as a contamination material. The research-included the completion of experimental work that consists of a series of loading tests carried on model of isolated square footing resting on clean and oil-contaminated sand. The contaminated sand layers were prepared by mixing the sand with crude oil at percent (10 and 20) % by weight of dry sand to simulate the field conditions. The depth of contaminated sand layer (d) under the footing was chosen depending on the footing width (B) as expressed by (d/B) ratio and varied as (0.5, 1, 1.5 and 2) to simulate the field conditions. The results showed that the contamination influences the load-settlement curves and leads to a reduction in its bearing capacity. The bearing capacity of the footing decreases significantly with increasing both the percentage of oil content and the depth of the contaminated sand layer. The results also showed that the presence of oil in sand changes the mode of shear failure in sand under the footing from local shear failure to the punching shear failure.

Bearing capacity evaluation of asphalt pavement based on dynamic deflection equivalent

In order to accurately evaluate the bearing capacity of asphalt pavement structure, the research group, on the basis of real-time temperature data of five kinds of asphalt pavement structure in Daxin experimental road, obtain the dynamic modulus main curves of various types of pavement materials and FWD dynamic modulus of the load acting frequency through dynamic modulus research in laboratory, and determine the dynamic modulus of the pavement structure material true value. According to the principle of dynamic deflection equivalent, this paper puts forward the evaluation method of predicting the bearing capacity of asphalt pavement based on composite modulus determination, pavement structure inverse calculation and bending stiffness modulus attenuation threshold. The evaluation results of five kinds of asphalt pavement structure bearing capacity of experimental road are consistent with the actual performance, which shows that the evaluation method of bearing capacity of asphalt pavement structure based on dynamic deflection equivalent is reasonable and effective.

Developing GEP tree-based, neuro-swarm, and whale optimization models for evaluation of bearing capacity of concrete-filled steel tube columns

The type of materials used in designing and constructing structures significantly affects the way the structures behave. The performance of concrete and steel, which are used as a composite in columns, has a considerable effect upon the structure behavior under different loading conditions. In this paper, several advanced methods were applied and developed to predict the bearing capacity of the concrete-filled steel tube (CFST) columns in two phases of prediction and optimization. In the prediction phase, bearing capacity values of CFST columns were estimated through developing gene expression programming (GEP)-based tree equation; then, the results were compared with the results obtained from a hybrid model of artificial neural network (ANN) and particle swarm optimization (PSO). In the modeling process, the outer diameter, concrete compressive strength, tensile yield stress of the steel column, thickness of steel cover, and the length of the samples were considered as the model inputs. After a series of analyses, the best predictive models were selected based on the coefficient of determination (R2) results. R2 values of 0.928 and 0.939 for training and testing datasets of the selected GEP-based tree equation, respectively, demonstrated that GEP was able to provide higher performance capacity compared to PSO–ANN model with R2 values of 0.910 and 0.904 and ANN with R2 values of 0.895 and 0.881. In the optimization phase, whale optimization algorithm (WOA), which has not yet been applied in structural engineering, was selected and developed to maximize the results of the bearing capacity. Based on the obtained results, WOA, by increasing bearing capacity to 23436.63 kN, was able to maximize significantly the bearing capacity of CFST columns.

Spatiotemporal characteristics of the bearing capacity of cropland based on manure nitrogen and phosphorus load in mainland China

The discrepancy between livestock breeding and crop planting in integrated crop-livestock system (ICLSs) usually cause nutrients surpluses to the arable land. Evaluation of regional land bearing capacity and identification of environmental critical regions associated with livestock in China are benefit to nationally- and regionally-specific livestock rearing. This study was conducted to demonstrates the changes in livestock industry from 1996 to 2016 in China and identify the environmentally critical regions of livestock farming by calculating the indexes of bearing capacity of cropland based on nitrogen (IN) and phosphorus (IP). The results revealed that the scale of livestock and poultry farming, manure production, and manure nutrients has increased over the past two decades. The livestock and poultry breeding quantity was 1290.8 million heads with a manure production of 4238.0 million tons in 2016. The manure N and P were 12.0 and 1.9 million tons with an increase of 5.8% and 5.9%, respectively. The N and P demand of crops from manure were 29.1and 4.5 million tons with an increase of 31.5% and 27.2%, respectively. The bearing capacities based on N and P were 2668.9 and 2554.7 million heads in pig equivalent, respectively. On the national level, the IN and IP were 0.43 and 0.45, respectively, which is categorized as Grade II. Livestock rearing in China was still within the bearing capacity of cropland. Both the Northeast and Northwest regions were categorized as Grade I, while Southeast region, Southwest region, the Middle and Lower Reaches of the Yangtze River and the North China were categorized in Grade II. There is still enough space for expansion of livestock and poultry farming in the Northeast and Northwest regions. In the North China region, Southwest region, the Middle and Lower Reaches of the Yangtze River, and the Southeast region, manure generated can be accommodated without any expansion in livestock breeding quantity. While livestock industry in Sichuan, Yunnan, Beijing and Tianjin need to be strictly controlled because of the grade of IV and V.

Evaluation of allowable bearing capacity of Ayila Soil, south-west Nigeria

Accurate determination of allowable bearing capacity of soil is key to geotechnical foundations design so as to prevent collapse of structures built on them. Allowable bearing capacity of the study location has been determined by shear wave velocity approach. The seismic data used in this study are the in-situ shear and compressional wave velocities values measured by a 12-channel signal enhancement seismograph. Three layers were detected by the method. Empirical formulations and mathematical relationship between seismic velocities and elastic parameters were used to evaluate the allowable bearing capacity and other parameters presented in Table 1. Results show that allowable bearing capacity for layer 1 ranges from 123.56 to 173.54kN/m2. Layer 2 ranges from 233.24 to 377.62kN/m2, while layer 3 ranges from 437.62 – 616kN/m2. It was observed that allowable bearing capacity increases with depth – a 13% difference between layers 1 and 2 while between layer 2 and 3 there is a 22% difference. By comparison, the allowable bearing capacities evaluated in this study are in agreement with empirical values of allowable bearing capacity of soils proposed by other scholars. Findings show the study location is suitable for geotechnical foundation designs.Keywords: Ayila, Shear wave velocity, Allowable bearing capacity, Coefficient of subgrade reaction

Study on the Natural Mineral Water Resource Bearing Capacity and its Driving Factors in Fusong County, Changbai Mountain Area, Jilin Province of China

In order to maintain the sustainable exploitation of the natural mineral water resources in Changbai Mountain Area with the continuously increasing exploitation intensity, information that is relevant to the exploitation of the mineral water resources from various aspects such as natural, social, ecological and environmental was collected based on the formation condition and mechanism of the regional mineral water resources. Meanwhile, the concept of the mineral water resources bearing capacity was brought up and the index evaluation system which contains the coupling of the information entropy and the grey correlation of the mineral water resources bearing capacity was set up. In this paper, the entropy and multi-objective decision making model were used for the evaluation of the mineral water bearing capacity, and the limited maximum exploitation quantity of the mineral water resources in the study area was determined according to the principle of the maximum entropy under the current and future condition in the region. The results shows that, the system entropy values of the mineral water resources in the study area in 2013, 2015 and 2020 are 7.6346, 7.5664 and 7.4289, respectively, showing a decreasing trend. At the same time, the composite indices of the mineral water resources bearing capacity in 2013, 2015 and 2020 are 0.6277, 0.5295 and 0.4068. The data indicate that with the exploitation of the mineral water resources in recent years, the mineral water resources bearing capacity is decreasing. However, the exploitation quantity of the mineral water resources in the study area can be increased for the time being in order to stimulate the circulation system of the groundwater and the recharge of the mineral water resources. The mineral water resources bearing capacity in each village and town of the study area is within the bearable state and has good exploitation prospects. It is necessary to point out that the exploitation threshold value in the study area is 35 million tons per year in order to realize the sustainable exploitation of the mineral water resources in the study area.

On site assessment of Azzone Visconti bridge in Lecco: Limits and reliability of current techniques

Abstract Ponte Azzone Visconti is a strategic middle age bridge built at north of Milan astride river Adda, along the road towards the centre of Europe passing from the Valtellina, the lordship of Milan and the Serenissima Republic. An on-site assessment of the bridge was carried out starting from the requirement expressed by the municipality of Lecco, consisting in the evaluation of the actual bearing capacity of the infrastructure with reference to the bridge classes defined in the national standards. The investigation used several approaches to quantify the bridge structural safety with reference to the vertical loads due to traffic and accidental seismic events and to highlight any critical issue. The paper is aimed at suggesting the most convenient analysis and maintenance choices, in order to conjugate the very significant historical value of the bridge to a sustainable evolution of its function.

Experimental evaluation of ultimate bearing capacity of the cutting edge of an open caisson

Open caissons are sunk into the ground by their own weight. A cutting edge of the caisson having a tapered inner face on loading – that is, raising of the steining – results in bearing failure by displacing the soil which is in contact with the cutting edge. The bearing capacity of the cutting edge and the soil flow mechanism depend on the configuration of the cutting edge, sinking depth and soil type. This paper presents the results of a series of 1g model tests, which investigate the effect of varying tapered angles of the cutting edge on the penetration resistance of the open caisson. The vertical failure load and corresponding vertical bearing capacity factor, N′γ, and the soil flow mechanism around the cutting edge are investigated. The soil flow mechanism and the influence of surcharge formed at the top level of the cutting edge due to advancement of the caisson in the ground are examined using the image-based deformation measurement technique. The results highlight that the cutting angle of the cutting edge and sinking depth play important roles in the load–penetration response and soil flow mechanism.

Оценка несущей способности буровой сваи для строительства высотного здания с развитым подземным пространством

Оценка несущей способности буровой сваи для строительства высотного здания с развитым подземным пространством

Evaluation of static bearing capacity of foundation based on impact wave due to driving steel pile

Evaluation of static bearing capacity of foundation based on impact wave due to driving steel pile

Bearing Capacity Model of Corroded RC Eccentric Compression Columns Based on Hermite Interpolation and Fourier Fitting

With an extension in service years, bridges inevitably suffer from performance deterioration. Columns are the main components of bridge structures, which support the superstructure. The damage of pier columns is often more harmful to bridges than that of other components. To accurately evaluate the time-varying characteristics of corroded columns, this paper proposes a new model for the bearing capacity evaluation of deteriorated reinforced concrete (RC) eccentric compression columns based on the Hermite interpolation and Fourier function. Firstly, the axial compression point, the pure bending point and the balanced failure point were selected as the basic points, and the deteriorated strength of these basic points was calculated by considering factors such as concrete cracking, reduction of reinforcement area, buckling of the steel bar, bond slip and strength reduction of confined concrete. After that, the interpolation points were generated by a piecewise cubic Hermite interpolating polynomial, and the explicit expression of the interpolation points fitting function was realized by the trigonometric Fourier series model. Finally, comparison studies based on measured data from forty-five corroded RC eccentric compression columns were conducted to investigate the accuracy and efficiency of the proposed method. The results show that: (1) the prediction results for bearing capacity of corroded RC columns are in good agreement with the measured data, with the average ratio of predicted results to test results at 1.06 and the standard deviation at 0.14; (2) the proposed model unifies the three stress states of axial compression, eccentric compression and pure bending, and is consistent with the continuum mechanics characteristics; (3) the decrements of axial load carrying capacity for 10% and 50% of the corrosion rate are 31.4% and 45.2%, while in flexure they are 25.4% and 77.4%, respectively; and (4) the test data of small-scale specimens may overestimate the negative effect of corrosion on the bearing capacity of actual structures. The findings in this paper could lay a solid starting point for structural life prediction technologies based on nondestructive testing.

Mechanical responses and acoustic emission properties of bolting system under short encapsulation cyclic thrust tests

Research on bolt reactions under cyclic disturbance is still sparse due to complex and special laboratory processes. This paper endeavours to reveal the mechanical response and acoustic emission (AE) characteristics of bolts under cyclic loading, and a series of short encapsulated cyclic thrust tests (SECTTs) was conducted. First, the threshold determining stress level in the cyclic process was defined based on monotonic thrust tests, and the stress distribution along the steel tube was obtained simultaneously. Second, tests specified by staged cyclic loading with varied cyclic counts at each stage were conducted, and the influence of the cyclic count on the stability of the bolting system was evaluated. Third, tests specified by staged cyclic loading with holding intervals were conducted, and the creep behaviour of the bolting system was investigated. Controlling factors such as frequency, amplitude, and cyclic count were comprehensively considered. Fourth, two tests specified by staged cyclic loading with high cyclic count were conducted, and the influences of high cyclic count were discussed. Generally, a short encapsulated bolt undergoing cyclic loading behaved differently from a statically loaded bolt, and some interesting results were observed based on analysis of AE properties, strengthening effects, creep behaviour, failure prediction, bearing capacity evaluation, etc. At the end of this study, the reasonability and deviation of SECTT adopting steel tubes to simulate rock masses in the laboratory were discussed.

Parametric study of a rapid bridge assessment method using distributed macro-strain influence envelope line

Abstract Dynamic strain-based methods are promising for bridge status assessment; however, the influences of vehicle parameters variations on their capabilities for damage identification are usually indeterminate. In this paper, parametric study for highway bridge rapid assessment method is conducted under moving vehicle loads, which is based on the distributed macro-strain envelope line. First, the relationship between the average bending stiffness and macro-strain history is studied according to the theory of the strain influence line. To determine the influence of different vehicle parameters (velocity, weight and axle numbers) on the method, a 1:10 scale model of a bridge-vehicle system is established for the parametric experimental study. A type of long-gauge Fiber Bragg Grating (FBG) sensor is used in the experiment. The empirical mode decomposition method (EMD) is applied to extract the static macro-strain component, and the maximum values of the static macro-strain histories are accumulated as the long-gauge strain envelope line. The experimental results show that the proposed method not only effectively identifies the location of damage but also damage extent and is not affected by the parameters of the vehicle. This method has engineering significance in bearing capacity evaluation and post-bridge structure reinforcement design.

Yield design‐based numerical analysis of three‐dimensional reinforced concrete structures

SummaryThe objective of this contribution is to present some new recent developments regarding the evaluation of the ultimate bearing capacity of massive three‐dimensional reinforced concrete structures which cannot be modeled as 1D (beams) or 2D (plates) structural members. The approach is based upon the implementation of the lower bound static approach of yield design through a discretization of the three‐dimensional structure into tetrahedral finite elements, on the one hand, the formulation of the corresponding optimization problem in the context of semi‐definite programming techniques, on the other hand. Another key feature of the method lies in the treatment of the concrete‐embedded reinforcing bars not as individual elements, but by resorting to an extension of the yield design homogenization approach. The whole procedure is first validated on the rather simple illustrative problem of a uniformly loaded simply supported beam, then applied to the design of a bridge pier cap taken as an example of more complex and realistic structure.

Evaluation of the Seismic Bearing Capacity of Shallow Foundations Located on the Two-Layered Clayey Soils

The seismic bearing capacity of shallow strip footings located on homogeneous soils is studied extensively. But the effect of building height and layering is not included in those studies. In this paper two-layered cohesive soils are studied along with building height effect. The formulation of the problem is derived by extending the limit equilibrium method developed by Merlos and Romo (J Soil Dyn Earthq Eng 26(2):103–114, 2006) for two-layered soils. A log-spiral potential failure surface is assumed, and the inertia forces are applied directly to the building and the failure block soil mass. The position of the failure surface is obtained by a minimization process for every earthquake shaking acceleration. Results show that the potential failure surface moves upward and its length shortens as the peak ground acceleration (PGA) increases, reducing the bearing capacity. Also, the effects of building height, PGA, ratio of cohesion of the layers and the thickness of the top layer on seismic bearing capacity factor (Nce) are studied.

Random bearing capacity evaluation of shallow foundations for asymmetrical failure mechanisms with spatial averaging and inclusion of soil self-weight

In this study, multi-block failure mechanisms in conjunction with Vanmarcke’s spatial averaging approach are used to evaluate random bearing capacity. This new approach examines the impact of the asymmetrical mechanism in spatially variable soil and the effect of anisotropy. The soil strength parameters were modelled by random fields that were discretized by spatial averaging along slip surfaces. Reliability indices were evaluated for symmetrical and asymmetrical cases. The results show that for higher values of horizontal fluctuation scales, the difference between symmetrical and asymmetrical approaches becomes negligible; however, for smaller values, it can be significant.