Calculation Of Load Carrying Capacity Research Articles

Experimental Study on Flexural Behavior of RC Piles with Basalt Fiber-Reinforced Polymer Bars and Load Carrying Capacity Calculation

The practical application of BFRPB (Basalt Fiber-Reinforced Polymer Bars) as a support structure in foundation pit and slope engineering is relatively under-researched. The indoor tensile test presented in this paper is carried out on the bond between BFRPB and different labelled concrete. The mechanical characteristics of BFRPB, the failure characteristics, and the load-carrying capacity were analyzed. The results of this study demonstrate that the normal section stress of concrete cylindrical components with BFRP has a good linear relationship and supports the rationality of the flat section assumption. In circular reinforced concrete BFRP structures, the failure of the pile load occurs in four phases, and the cracking load is in the range of 51% to 67% of the normal yield load. The main bars increase in strain with load but become attenuated in the compression zone. The deformation of the main bars increases with the load but becomes muted in the compression zone. Based on the method of calculating the load-carrying capacity of GFRP-reinforced RC piles and the normal limit load-carrying moment obtained from in-door tests, the bending moment correction coefficient in the calculation formula for the load-carrying capacity of BFRP-reinforced RC piles was then obtained.

Fire behavior of full-scale cold-formed steel center-sheathed shear walls under combined loads

An innovative cold-formed steel center-sheathed shear walls (CFSCSSWs) was proposed in this paper to improve the horizontal load-carrying capacity of conventional cold-formed steel walls. However, the fire behavior of this wall configuration was particularly worthy of attention because it was designed to be used in multi-story buildings, and there is still a lack of in-depth exploration of the fire performance and high-temperature horizontal load-bearing capacity of CFSCSSWs under combined loads. In this study, a compression test was first carried out to obtain the vertical load-carrying capacity of a full-scale CFSCSSW, followed by a fire test on a similar CFSCSSW subjected to combined vertical and horizontal loads to investigate the fire behavior of walls. Then, a finite element model was established and validated by test results to investigate the influence of various critical factors, including vertical and horizontal load ratios, height-width ratio, and sheathing thickness, on the fire behavior of the CFSCSSW. The results showed that the vertical load ratio presented a larger influence on the fire behavior of CFSCSSWs compared to the horizontal load ratio. The increasing aspect ratio can slightly improve the fire resistance of the wall under the same load ratio. The wall with a 0.8 mm thick sheathing exhibits better fire behavior under the same load ratio. A high-temperature horizontal load-carrying capacity calculation method for CFSCSSWs was proposed, and its good accuracy was found.

Eccentric load-carrying capacity calculation of L-Shaped Columns with recycled aggregate concrete-filled tubes

A composite L-shaped column made of square steel tubes filled with concrete is well-suited for residential steel structures because it effectively prevents the beams and columns from protruding from the walls, thus maximizing the usable space within a room. Recycled aggregate concrete (RAC), a sustainable material, can efficiently recycle construction waste and reduce energy consumption. However, compared to natural concrete, RAC has lower elastic modulus and compressive strength. When RAC is filled into steel tubes, it effectively restrains the RAC and allows it to support the internal buckling of the steel tubes. This study investigates L-shaped columns of recycled aggregate concrete-filled steel tubes (L-RACFST) through eccentric compression tests and numerical validation. By applying the superposition principle, the study evaluates the eccentric compression strength calculation method of L-RACFST columns and plots the N-M relationship curve. Comparing the results of the tests and numerical studies, it is evident that the derived formula is reliable for predicting the eccentric compression bearing capacity of L-RACFST columns. Furthermore, the N-M relationship curve drawn from the formula provides a more accurate prediction of safety. This paper delves into the stress mechanisms of L-RACFST columns under eccentric compression loads. The calculation formula can be used to determine the bearing capacity of L-RACFST columns under eccentric compression loads, and the N-M relationship curve can be employed to predict the safety performance of L-RACFST columns under such loads.

Eccentric compression capacity of circular CFST columns under random pitting corrosion

This study explores how random pitting corrosion affects the ultimate eccentric load-carrying capacity of corroded CFST columns at various corrosion levels. The research examines how the load-carrying capacity of circular steel tube concrete columns changes under eccentric loading conditions due to variations in the quality loss rate of the external steel tube caused by corrosion. The established finite element model is validated using existing experimental data, showing a high degree of accuracy. Additionally, the study investigates influencing factors, including corrosion thickness (tc/t), both constant and random corrosion (tc/t), eccentricity (e), corrosion pit diameter (Dc), material strength, and component dimensions. The findings reveal how these parameters affect the reduction of eccentric compressive load-carrying capacity. To visually illustrate this effect, the concepts of load reduction factors Rcs′ and Rc′ are introduced, representing the ratio of load-carrying capacity before and after corrosion. Based on extensive random finite element analyses, we propose a load-carrying capacity calculation formula for the eccentric load reduction factor applicable to corroded circular CFST columns. The study also demonstrates that axial compression can be considered a special case of eccentric loading with an eccentricity of 0. Consequently, by incorporating stability and eccentricity reduction factors, adjustments are made to existing axial load-carrying capacity prediction formulas, resulting in the calculation formula for the reduction factor Rc′. By measuring the local quality loss rate of the external steel tube of corroded circular CFST columns, it is possible to predict both axial and eccentric load-carrying capacities.

Experimental and Numerical Study on Flexural Behavior of a Full-Scale Assembled Integral Two-Way Multi-Ribbed Composite Floor System

An assembled floor system is a main step in the industrialization of construction in civil engineering, where the stiffness and anti-crack properties under designed loads and its self-weight are the main concerns. This paper presents a new type of assembled integral composite floor system, which is composed of precast ribbed bottom slab, lightweight infills, cast-in-situ upper slab and joints. Through the couplers for squeezing and splicing of longitudinal bars, shear keys and cast-in-situ joints between the precast panels and cast-in-situ upper part, the whole hollow floor system could not only exhibit satisfactory mechanical performance, but also lower the self-weight and shorten the construction time. To study its flexural behaviors, a full-scale specimen sized 9.2 m × 9.2 m was designed and tested under static area load. With the load increased to the designed loads of Chinese design code GB50010-2010, mechanical performance (i.e., crack distribution, deformation and stress distribution) were analyzed. To further study its load-carrying capacity and working mechanism, an effective finite element model was established in ABAQUS and compared with experimental and simulation results. It was found that the deflection of the floor under the normal service load and the crack width met the needs of normal use, and the finite element model could serve as a reliable method for the load-carrying capacity calculation.

Applicability of classic analytical calculation approaches for the design of plastic gears

AbstractPlastic gears are produced cost-effectively in high volume but mainly for applications under low load. Current trends are leading to the design and application of plastic gears for more demanding operating conditions. This requires finding the optimum macrogeometry for the application, which is determined in practice using iterative design processes. Numerical and analytical approaches are available for the design of gears. Due to their speed, only the latter are suitable for an iterative design process. However, the approaches currently used in the calculation programs are designed with a focus on steel gears. Their applicability to gears made of plastics, which material properties differ drastically from those made of steel, is therefore only partially possible.The paper presents an investigation into the applicability of the classic analytical calculation approaches of Weber/Banaschek and Schmidt for contact analysis and the load-carrying capacity calculation of plastic gears. For this purpose, the results from analytical calculations are compared with those from numerical calculations. In addition, a comparison is made with typical standards (DIN3990, ISO6336) and guidelines (VDI2736).As a result, the paper provides an initial statement on the transferability of results from steel-focused analytical approaches to gears made of plastic. In addition, calculation results are identified in which particularly large differences occur between the various calculation approaches and which must be considered in the design phase.

Simulation Study on the Tribological Characteristics in the Meshing Contact in the Context of the Load Carrying Capacity Calculation of Internal Gears with Unbalanced Sliding Conditions

Planetary gearboxes are characterized by a high power density and a compact design with coaxial in- and output. Consequently, planetary gear units are frequently used in many practical applications, e.g. in wind energy and industrial transmission systems as well as in automotive applications such as automatic transmissions. As a result of the scaling-up of the required system power, the risk of flank damages increased during the last decade. Certain damage types, such as pitting and micropitting, occur predominantly in contact areas of negative specific sliding on the tooth flank surface. Unlike external gears, internal gears offer the possibility of positioning the pitch point C outside of the active profile. Depending on the gear design, this allows a complete avoidance of negative specific sliding either on the planet or on the ring gear. In contrast, the corresponding gear is subjected to negative specific sliding only. It can be assumed that the lifetime regarding flank damages of each meshing partner can be affected by different positions of the pitch point and the resulting differences in the specific sliding, which allows an optimization of the full gear system, taking into account e.g. the load carrying capacity reserves for different material pairings. It is to be noted that such gear designs are already part of some practical applications.However, the existing analytical approaches within standardized load carrying capacity calculation methods are typically based on investigations considering external gears with balanced sliding conditions. Systematic results on internal gear designs with pitch point positioned outside of the active profile are not available.Within this paper, extended theoretical studies on the tribological characteristics of different internal gear designs are presented. Therefore, a reference geometry with balanced sliding conditions is compared to internal gears with pitch point below respectively above the active profile. The focus of the studies is the analysis of the lubricant film thickness and the contact temperature in the meshing contact. Referring to this, a high-order TEHL contact simulation model was used. The results of the numerical analysis with the FZG calculation software TriboMesh are compared to different analytical approaches in the context of the calculation of load carrying capacity to derive recommendations for the design of internal gears.

Tension of ground pressure on the foundations of railway catenary supports

This paper presents the results of calculations of the values of soil pressure stresses on the base of the contact network supports by the developed program NDGFOKS in the programming language - C#. Design and construction of the foundations of the contact network supports is provided in accordance with the requirements of regulatory documents and technological charts. When selecting the methods of fastening the overhead contact network supports in the ground of the earth bed, experience in construction of overhead contact network supports in various engineering and geological conditions was taken into account. The methods of calculation of load-carrying capacity of the contact network bases on the ground were analyzed. Methods of fastening the overhead contact network pylons, including those on the weak ground bases, were given. The NDGFOKS program has been developed in the C# programming language in order to calculate the stresses of soil pressure on the foundation faces. The program has been developed taking into account the variety of soils, the characteristics of foundations and the methods of their driving. A block diagram and a diagram of the stresses of soil pressure on the foundations of the contact network supports at different foundations are given.

木造平面混構造のコア配置を考慮した設計用地震力の研究

Time history response analyses of horizontal hybrid wooden structures with RC core on one or both sides are conducted considering the elasto-plasticity of the wooden part with Wayne-Stewart model as hysteretic characteristics. Then, by comparing the results with the static elasto-plasticity analyses, the effects of amplification of wooden part and eccentricity are verified, and the consistency with the horizontal load-carrying capacity calculation, such as the setting of the structural characteristics factor DS, is confirmed to form a concrete background for the design of horizontal wooden structures.

Diagnostics and Evaluation of Two Atypical Girder Bridges on Railway Line

The paper is focused on diagnostics and calculation of load-carrying capacity of the two atypical girder bridge objects on the railway line between Púchov and Považská Bystrica in Slovakia. These are skewness reinforced concrete (RC) girder bridges with three girders. The non-typicality is given by the fact that the spandrel girders are in the longitudinal direction, but the middle girder is relatively wide and is perpendicular to the clearance (not in the longitudinal direction). The diagnostics was performed on the objects aimed at determining the material and geometric characteristics, which served as a basis for the numerical model. A 3D scanner was also used to determine the geometric dimensions. The load-carrying capacity was subsequently determined on the bridges. The recalculation and diagnostics revealed the fact that bridge structures can still be used, but have to be reconstructed. This is a prime example of reusing in practice, i.e. how the old bridges can be further used, which means a significant saving of CO2 emission that would be produced by demolishing the old bridges and building new ones

Optimization design of high-strength cold-formed steel stiffened lipped channel columns under axial compression

In China's current market, there are many cold-formed thin-walled members used to construct low-rise light steel buildings. The members are mainly manufactured by 550 MPa yield strength aluminized zinc-coated steel sheets with a width of 180 mm. Since the load-carrying capacity of different section shapes significantly varies within a constant sectional area, finding the section shape with the highest load-carrying efficiency is one of the key problems. In this paper, the optimal section under axial compression is investigated. Initially, a program was written to select several candidate sections with high efficiency based on the theoretical load-carrying capacity calculation. Then, finite element analyses and loading tests were carried out on the selected sections, and the section with the highest load-carrying capacity was determined as the optimal section. The results indicate that the variation trends of the load-carrying capacity of the members with different section sizes obtained by theoretical calculation, finite element simulation, and loading test were consistent. When the ratio of web height to the sum of flange and lip width is between 1 and 2, the axial load-carrying capacity of the member is relatively high. The distortional buckling capacity is relatively higher when the lip width is larger. The short columns with optimal sections undergo local-distortional interaction buckling, whereas the long columns with optimal sections undergo the interaction among local, distortional, and overall buckling. The optimal section size, i.e., web height of 81 mm, flange width of 37.5 mm, and lip width of 12 mm, is proposed for engineering design reference.

Compression behavior of CFRP–confined coral aggregate concrete (CCAC) circular stub columns

Carbon fiber–reinforced polymers (CFRPs) have excellent tensile strength and great resistance to chloride ion corrosion. In the 21st century of rapid development in marine construction, the composite structure of CFRP and coral aggregate concrete (CAC) has broad development prospects and great research value. This paper proposes a CFRP–confined coral aggregate concrete (CCAC) column as a novel composite column suitable for use in marine environments. Eighteen CCAC circular stub columns were constructed, and compression tests were carried out under axial and eccentric loads. The compression behavior, including the load–carrying capacity, stress–strain relationship, and ductility of CCAC stub columns was investigated. Test results show that the CFRP sheets greatly improve the load–carrying capacity and ductility of the CAC stub columns. Among the three influencing factors, the influence on the load–carrying capacity and ductility of the CCAC stub columns is eccentric distance, the number of CFRP layers, and the CAC strength in descending order. Finally, the load–carrying capacity calculation method and the stress–strain relationship of CCAC stub columns under axial compression were established, and an eccentric reduction coefficient was proposed to calculate the load–carrying capacity of CCAC columns under different eccentric distances.

Numerical Analysis on Flexural Behaviors of Prestressed Reinforced Concrete Beams Strengthened with NSM CFRP Strips

This paper presents the numerical analysis of prestressed reinforced concrete (PRC) beams strengthened with near-surface mounted (NSM) carbon fiber reinforced polymers (CFRP). ABAQUS finite element software was used to simulate the existing test beams to investigate the flexural behaviors of PRC beams strengthened with NSM CFRP strips. The finite element model of beams strengthened with NSM CFRP strips was established. The finite element calculation results were compared with the experimental results to verify the accuracy and effectiveness of the model. Based on this model, the influences of concrete strength grade and amount of CFRP strips on the flexural behaviors of directly strengthened beams and the cycle numbers and overload amplitude on the flexural behaviors of damaged strengthened beam were further analyzed, and the load-carrying capacity calculation formula of PRC beam strengthened with NSM CFRP strips was established. The results showed that the simulation results and the theoretical calculation were consistent with the test results. With the increase of concrete strength grade and amount of CFRP strips, the ultimate load of directly strengthened beams increased significantly, with a maximum increase of 21.3% and 23.0%, respectively. When the concrete strength grade exceeded C50, the improvement of the ultimate load was limited. When the overload amplitude was less than 60% of the ultimate load, the cycle numbers (within 500 times) had little effect on the yield load, ultimate load, and deformation. When the overload amplitude was higher than 60% of the ultimate load, the deformation increased, and the ultimate load decreased with the increase of the cycle numbers. The larger the overload amplitude, the smaller the ultimate load, and the larger the deformation under the same cycle numbers.

Three-dimensional Nonlinear Finite Element Analysis for Load-Carrying Capacity Prediction of a Railway Arch Bridge

Calculation of load-carrying capacity of old railway masonry arch bridges as crucial infrastructures is one of the vital issues in the railway industry. The field test of the 2PL20 bridge reveals important properties such as the initial stiffness and cracking pattern, but the ultimate capacity of the bridge under static loading was not achieved due to the field limitations. Therefore, the present study aims to predict the total nonlinear response of the 2PL20 bridge up to the failure status. All the geometrical characteristics of the 2PL20 bridge are modeled precisely and the failure state is predicted using the three-dimensional nonlinear finite element analysis. Moreover, to determine the load-carrying capacity of the 2PL20 bridge, the behavior of materials is regarded nonlinearly in which the Williams and Warnke and the Drucker-Prager failure criteria are taken into account for concrete and soil materials, respectively. To obtain precise results of ultimate capacity of the 2PL20 bridge under field test, the vertical and horizontal displacements of the crown on the northern span are chosen as the calibration criterion and, consequently, the vertical and horizontal load-deformation curves are verified based on the field test results. The obtained results indicate that the load-carrying capacity of the 2PL20 bridge equals 8880 kN under the static field test. Finally, the calculated safety factor is equal to 3.2 and increasing axial load up to 35-ton is admissible based on UIC 776-1 for a 25-ton axial load.

EFFECTS OF DESIGN PARAMETERS ON STATIC EQUIVALENT STRESS OF RADIAL ROLLING BEARINGS

The aim of this study is to theoretically investigate the effects of design parameters on the static equivalent stress of radial rolling bearings, such as the point contact case for ball bearings and line contact case for roller bearings. The contact pressure, contact area and von Misses stress of bearings are calculated based on geometrical parameters, material parameters and loading parameters by using the developed MATLAB program. To achieve this aim, both the maximum contact pressure pmax and Von Mises effective stress σVM are simulated with respect to design parameters such as varying ball and roller element diameters and varying ball and roller element elasticity modulus. For the point contact case and line contact case, it was concluded that increasing the diameter of ball and roller elements results in reducing the maximum contact pressure pmax Furthermore, increasing the elasticity modulus of the ball and roller elements results in increasing the maximum contact pressure σVM. Furthermore, increasing the elasticity modulus of the ball and roller element results in increasing the maximum contact pressure pmax and Von Mises effective stress σVM because of the decrease of contact area A. The determination of the diameter of the ball and roller elements and the selection of material are crucial and play an effective role during the design process. Therefore, bearing designers and manufacturers should make the bearing geometrical dimensions as large as possible and bearing material as elastic as possible. Furthermore, the stress-based static failure theory can also be used instead of the standard static load carrying capacity calculation. Moreover, Von Mises stress theory is also compatible with the finite element method.

Outline of AIJ Standard for Lateral Load-carrying Capacity Calculation of Reinforced Concrete Structures

Outline of AIJ Standard for Lateral Load-carrying Capacity Calculation of Reinforced Concrete Structures

Axial compression of steel–timber composite column consisting of H-shaped steel and glulam

A steel–timber composite (STC) column made of H-shaped steel and glulam is proposed in this paper. This STC column is constructed by wrapping the H-shaped steel with the adhesive-applied glulam, which provides confinement to reduce the buckling behaviour of the inner steel. Six STC specimens with lengths of 1100 mm, 1700 mm and 2300 mm were studied using an axial compression test in comparison to three steel and three timber specimens. The distinctive behaviours of the specimens were identified, including the failure mode, load–axial displacement relationship, load–lateral deflection relationship and load–axial strain response. The results demonstrated that the mechanical properties of the STC column are significantly affected by column length. The interaction mechanism between the steel and timber materials was evaluated by analysing the yield strain and the ductility coefficient. The composite effect of the STC column was also discussed by comparing the average strengths. Furthermore, the load-carrying capacity calculation formula including parameter selection of the STC column when yielding was proposed.

On the Influence of Corrosion on the Load-Carrying Capacity of Old Riveted Bridges.

Steel corrosion is one of the most dominant factors in the degradation of transport infrastructure. This article deals with the impact of the atmospheric corrosion of structural steel on the load-carrying capacity of old riveted bridge structures. A study on the impact of corrosion losses on the resistance and, thus, the load-carrying capacity of eight chosen bridge members with riveted I-sections from three different bridge substructures is presented. The load-carrying capacity calculation is carried out using modern procedures and on the basis of the diagnosed state of the structural elements. Within the analysis of the results, the need for long-term in situ corrosion measurements, as well as the need for regular inspections on the existing bridges are also discussed.

Outline of “AIJ Design Guidelines for Lateral Load-carrying Capacity Calculation of Prestressed Concrete Buildings（Draft）”

日本建築学会では，「プレストレストコンクリート造建築物の保有水平耐力計算指針（案）・同解説」を発刊した。1981年の「新耐震設計法」が導入されてから，多くのプレストレストコンクリート（PC）建築物で用いられている保有水平耐力計算法を日本建築学会として初めて明文化した。一次設計時に，損傷制御設計として部材の使用限界応力によるチェックを行うこととし，二次設計で安全性確保のため，建築物の崩壊メカニズムによる保有水平耐力のチェックを行うこととした点に本指針の特徴がある。

Investigation the peculiarities of deformation and strength of timber using laser interferometry method

Problem statement. Correct assessment of load carrying capacity of connections is crucial for ensuring the structure reliability. The initial parameter for the calculation of load carrying capacity of the timber structures connections is the characteristic embedment strength (the strength of timber massive under dowel penetration). This characteristic can be determined using empiric formulas or through standard experimental investigation. Currently a wide database on the results of the experimental assessment of stress-strain state of timber structures connections exists, which covers the questions of determination of failure patterns, failure load, strength, “load-deformation” dependences etc. Nevertheless, a combination of the standard investigation methods with non-standard techniques allows obtaining more detailed information about the interaction between elements of the connection. The registration of the displacement fields of the surface or volume of the element is possible using optical physics methods, e.g. laser holographic interferometry. The purpose of the article is to investigate the strength and peculiarities of the deformation of timber under the influence of metal dowel using laser holographic interferometry method. Conclusion. As a result of experimental investigations, load-displacement curves, failure loads and maximum displacements were obtained for the samples tested. At each loading stage, interferograms were recorded and three-dimensional graphs of the deformed surface of the sample were obtained, which clearly represent the nature and evolution of the interaction between dowel and timber. The resulting complex of data on the deformation and strength characteristics in further studies will be used to develop and verify the design model of the dowel connection of timber elements taking into account nonlinear work.