Search

A numerical study has been carried out to know the lateral torsional buckling of hot rolled steel I beam strengthened using steel plate at the bottom flange. A linear and non-linear analytical study has been carried out using Abaqus software to know the behaviour of beams. For this analysis, ISMB500 is strengthened using a steel plate by varying the thickness of the steel plate. Welded connection is used for connecting the steel plate and bottom flange of a steel beam. The research work aims to determine the ultimate bending strength of the unstrengthened and strengthened I beam. The load deflection behaviour of strengthened and unstrengthned beams was also studied in this research work. Strengthening of steel beam using a steel plate significantly increases the load carrying capacity of steel I beam between 6% and 22%. The percentage of increasing load carrying capacity is depend upon the thickness of plate.

An overview of the current and future trends in wind turbine blade structural design process is presented. The main design principles and failure mechanisms of blades in operation are assessed and explained through an industry point of view, in a realistic manner. A number of failure modes which are not addressed sufficiently in the certificate guidelines are presented. An example on how to use the new design philosophy is presented. The manufactured prototype is a 44m long load carrying spar and the weight is reduced by 40%.

Research focusing on the effects of pre-damaged level on the effectiveness of concrete repairing using external confinement is quite limited. In addition, the use of active confinement in concrete repair works is yet to be explored. This study extends the investigation on repairing reinforced concrete (RC) columns to the active-typed confinement. Experimental tests were conducted to investigate the applicability of active confinement in repairing RC columns with varied pre-damaged levels. The applicability of steel strapping confinement in repairing RC columns with the varied pre-damaged levels was confirmed through experimental works, which involved testing of 21 RC columns under monotonic uniaxial compression. The overall responses of the specimens were investigated in terms of crack pattern, load carrying capacity, axial displacement, stiffness and ductility of repaired columns. The test results have shown that the restorability of confinement was significantly affected by pre-damaged levels. It is also observed that the increase in confining volumetric ratio can restore both strength and ductility of repaired RC columns up to 171% and 172%, for the same pre-damaged level.

The rounded corners have significant influences on the buckling processes and carrying capacity of thin-walled steel structures. This paper was intended to investigate the influences of rounded corners on the performance of single-coped beam with slender web. The mechanical behaviours of two typical single-coped beams with different coped depths were experimentally investigated first. The finite element (FE) model was proposed and the accuracy was verified by comparing it with the experimental results. Based on the proposed FE model, the influences of different radius for rounded corners ( R c ) were investigated. It was concluded that the application of rounded corners has great impacts on the failure modes and buckling processes of single-coped beams. It was also found that the energy-dissipating capacity as well as load carrying capacity increased significantly with the application of round corners, especially for single-coped beam with deep coped depth. The round corner index, which considered the influences of both rounded corner and coped depth, was proposed via fitting with the simulational results. A typical design example considering the round corner index was also provided and a more accurate result was achieved.

A series of laboratory model tests have been carried out to examine the behavior of non-encased and geogrid encased conventional aggregate column (CAC) and fly ash brick bats column (FAC) resting on soft clay soil. In the present study, a series of load tests were carried out in a circular model tank of size 300 mm diameter and 400 mm height on soft clay soil with one, two and three columns of conventional aggregate (CA) and fly ash brick bats (FA). The experimental variables fixed in this study were aggregate type (CA and FA), encasement depth (non-encased, partially encased and fully encased), different length to diameter (l/d) ratio (8 and 10) and diameter of columns (30 mm and 40 mm). Based on the experimental results, it was seen that CAC have higher load capacity than FAC and the improvement was 2.72 times greater than untreated soft soil. The fully encased geogrid CAC possess higher load carrying capacity and the order of improvement was 3.63 times larger than untreated soft soil. In addition to that the load capacity of CAC and FAC increased with increasing the l/d ratio and diameter of CAC and FAC. The 40 mm diameter FAC possesses higher load capacity and the load capacity improvement was identified as 1.12 times greater than 30 mm diameter FAC. Further, the experimental results were validated by numerical analysis.

This article discusses the feasibility of a geogrid-encased deep cement mixing (EDCM) pile for enhancing the load-carrying capacity (Qult) of a conventional deep cement mixing (DCM) pile, based on the results of experimental and numerical investigations. Firstly, physical model tests were conducted to observe the load–settlement response and load-transfer mechanism. Subsequently, a series of three-dimensional (3D) finite-element analyses was performed to investigate the effect of the stiffness and length of the geogrid encasement. The results indicated that the geogrid encasement effectively improves the Qult of the DCM piles by a factor of two. With the additional confinement provided by the geogrid encasement, the geogrid can also provide a greater contribution to the loading transfer. The increase in Qult became more significant with a lower strength of the DCM. For a particular amount of geogrid, the EDCM pile with a thicker geogrid provided a higher Qult than that with a longer geogrid. The optimum length of the geogrid-EDCM pile was found to be approximately twice that of the pile diameter. Finally, a chart for estimating the efficient effect of geogrid encasements on the Qult of EDCM piles was proposed.

CFRP ropes are relatively new and cheap materials that can be used in strengthening and rehabilitating RC elements. This research was designed to investigate the experimental behaviour of heat-damaged and unheated RC beams strengthened and retrofitted using near-surface mounted (NSM) carbon fiber polymer (CFRP) ropes. Ten RC beams were tested under a four-point loading test. Five beams were subjected to 700°C for 3 h and were partially damaged by heat while the other remaining beams were unheated. Several strengthening configurations were adopted where CFRP ropes were continuously anchored along the beam length. The flexural strength of the test specimens was then predicted using the ACI-440 guidelines and compared to the experimental results. Test results showed that the continuous strengthening configuration is considerably efficient in increasing the flexural strength of the RC beams. Adopting two layers of continuous CFRP ropes along the beam length, anchored at the tensile reinforcement level, increased the load capacity and stiffness of the unheated beams by 60% and 78%, respectively. It also restored the load capacity of the heat-damaged beams with an additional 47% in its’ load carrying capacity, but it decreased their peak deflection. Test results showed that the current ACI-440 guidelines that are designed for predicting the flexural strength of RC beams strengthened with NSM bars could be applied to predict the flexural strength of RC beams strengthened with NSM CFRP ropes with a suggested modification factor for the effective strain.

This study was undertaken to further knowledge in relation to the effect of elevated temperature on performance of adhesively bonded CFRP-to-steel joints subjected to peel loading. Two epoxy adhesives, Adhesive A and Adhesive B, were assessed with regard to their aging behaviour at two elevated temperatures and for two exposure periods. Adhesive coupon specimens and a modified Mode I fracture test arrangement for use with dissimilar materials was used in the test programme. In total, thirty CFRP-to-steel bonded specimens and thirty adhesive coupons were evaluated. Exposure of coupons of both adhesives to elevated temperatures resulted in a considerable reduction in elastic moduli. Maximum strain of adhesive coupons fabricated with Adhesive A and B experienced an overall average increase of 30% and 39%, respectively, after exposure to elevated temperatures. The maximum failure load of fracture specimens manufactured with Adhesive A and B reduced up to 9% and 12%, respectively, after exposure to elevated temperature. Despite possessing higher strain energy release rate and higher load carrying capacity of fracture specimens manufactured with Adhesive B compared to Adhesive A, the bonding performance of Adhesive B is more affected by elevated temperature and this needs to be noted when using Adhesive B in areas with hot climates.

Постановка задачи. Многолетняя бесконтрольная эксплуатация моста привела его несущие конструкции к аварийному состоянию. Для дальнейшей его безопасной эксплуатации требуется конструктивное укрепление практически всех элементов. Так как их прямое упрочнение невозможно без нарушения подлинного облика, авторы поставили перед собой задачу косвенного усиления конструкций путем подбора на математической и физической моделях допустимых схем и предельных значений нагрузок на пролетное строение. Результаты. Для решения поставленной задачи проведены и проанализированы результаты качественных и количественных теоретических исследований объекта культурного наследия «Комплекс Ольденбургских. Мост влюбленных. 1900 г.». Осуществлено инструментальное освидетельствование памятника, выполнена и испытана лабораторная модель подлинного сооружения. Выводы. Полученные в результате всесторонних исследований данные позволили оценить ресурс несущей способности конструкций объекта культурного наследия, проанализировать возможности загружений пролетного строения моста и сделать заключение о его надежной эксплуатации в современных условиях. Statement of the problem. Many years of uncontrolled operation of the bridge led its supporting structures to an emergency condition. For further safe operation of the bridge, structural strengthening of almost all elements is required. Since their direct strengthening is impossible without violating the original appearance, we set the task of strengthening the structures indirectly by choosing permissible schemes and limit values of loads on the span on mathematical and physical models. Results. To solve this problem, we carried out and analyzed the results of qualitative and quantitative theoretical studies of the object of cultural heritage «The Oldenburg’s complex. Lovers Bridge. 1900». We carried out an instrumental inspection of the monument, designed and tested a laboratory model of the original structure. Conclusions. The data obtained as a result of comprehensive studies made it possible to assess the load-bearing capacity of the structures of the cultural heritage object, analyze the possibilities of loading the bridge span and make a conclusion about its further safe operation in modern conditions.

The load carrying capacity of gears can be significantly increased by nitriding. However, the required nitriding hardening depth depends on the stress level and the gear size. In order to achive a high fatigue resistance and durability of nitrided gears an adequate nitriding hardening depth is necessary. In industrial practice, a nitriding hardening depth (NHD) of about 0.6 mm is currently regarded as the upper limit that can be reached within a reasonable time and cost. This also limits of the load carrying capacity of nitrided gears, in particular with increasing gear sizes. Therefore, case hardening is the main treatment used with increasing gear sizes, although nitriding provides some advantages over case hardening. However, with an increased nitriding hardening depth, a significant increase in the load carrying capacity of nitrided gears for medium and larger gear sizes could be expected, which will be discussed in this publication. In order to evaluate the expected potential of the load carrying capacity of nitrided gears with an increased nitriding hardening depth of NHD ≈ 0.8 to 1.0 mm (deep nitriding heat treatment) made out of the materials 31CrMoV9 (1.8519), 30CrNiMo8 (1.6580) and 32CDV13 (alloy for aerospace applications according to AIR 9160), experimental investigations were carried out, which will be discussed in this publication. Both, the tooth root bending strength and the flank load carrying capacity were investigated.

Plastic gears and their numerous applications have become an integral part of industrial practice. In particular, the ability to produce large numbers of gears cost-effectively using injection molding techniques is making a significant contribution to growing market shares. Compared to conventional steel materials, however, the material properties of thermoplastics differ fundamentally. In particular, the high temperature dependence of the material properties and the lower strength pose challenges for designers. Against this background, theoretical and experimental studies on the operating and service life behavior of different thermoplastic materials have been conducted and evaluated. In addition to theoretical investigations on the tooth flank load carrying capacity, comprehensive measurements on temperature behavior were carried out and compared to common methods of temperature calculation for plastic gears. Experimental investigations on the tooth flank load capacity by means of back-to-back tests of different materials and their evaluation show the potential of thermoplastic materials for the application in power transmitting drivetrains. This contribution will give an overview of the performed research work and summarizes main results of these studies.

In this study, flexural behavior of hybrid reinforced concrete beams were investigated theoretically and by the finite element method. Within the scope of the study, beams with identical geometry and concrete compressive strength; designed as having different reinforcement ratios. The results obtained from the theoretical work and finite element method were commentated by using load-displacement curves, load carrying capacities and strain indices. The effects of the fibrous polymer / steel ratio (Af / As) on the stiffness, strength and midpoint displacement of the beams were investigated. In addition, the effects of reinforcement ratio on load carrying capacity and deformability indexes were investigated.

A computational method is presented as a method for solving a plane contact problem of the theory of elasticity to determine the contact strength and tribological durability of sliding bearings. The effect of load and radial clearance on the initial contact pressures and their reduction due to wear is studied. The durability of the bearing is estimated. Qualitative and quantitative regularities of changes in contact parameters and durability from the factors under study are established. In particular, it has been shown that both contact angles and maximum contact pressures are approximately linearly dependent on the load, and the durability decreases nonlinearly with increasing load.

The flash temperature is one of the important factors for evaluating the scoring resistance of the gear teeth. In the present paper a numerical solution of the flash temperature for W/N circular arc gear due to moving heat source is done taking into account the partitioning of the heat in the contact zone to each tooth and all the variables for the design of this type of gears. Tooth load speed of rotation, module, radii of curvature, helix angle, gear ratio, number of teeth and contact ratio are considered. The theoretical results of the flash temperature arte presented and discussed with the above variables. A curve filling of the results is done and the following formula derived for the flash temperature ᶿ/µ = CP0.9725, N0.369, m0.968, p 0.994, CR0.706, β0.193 This formula represents a simple tool for the designer to calculate the flash temperature the corresponding load carrying capacity and life of the gear are determined. The study also shows that there is a certain minimum value for the flash temperature with the change of the gear ratio.

The load support of a lubricating film that separates the surfaces textured by identical equidistant spaced hemispherical pores was investigated. Two-dimensional time-dependent Reynolds equation is solved numerically for different pore-radius-to-gap and cell-dimension-to-pore-radius ratios and for different relative pore positions of opposite surfaces. The results are compared with the data obtained for the case when only one of the opposite surfaces is covered with pores. The obtained data show a maximum in the carrying capacity of the lubricating film when the cell-to-pore-radii ratio is approximately equal to two, in the case of two opposite surfaces with pores. At small pore radii and with increasing cell dimensions, the load support of two surfaces with pores is much greater than in the case of one surface with pores. This behavior reverses with increasing pore diameter. The presented analysis and the provided MATLAB programs are applicable for mechanisms having rubbing mechanical parts with surfaces covered with pores.

Clearance in ball bearing influences the startup torque and stiffness of bearing and affects the load distribution, load carrying capacity, and life of bearing. The present work is related to deep ...

Bamboo has been significantly and rapidly used to build temporal and permanent structures since time immemorial. However, this renewable natural material has a low bearing capacity, limiting its application to structures under light loads. Therefore, this research was carried out to determine an innovative scheme capable of enhancing bamboo's load-bearing by filling the cavity with cement mortar. Furthermore, a study was carried out to experiment flexural load carrying capacity and the deflection of mortar-filled structural bamboo by considering the diameter and node parameters. A total of 12 specimens were examined using a four-point bending protocol. The result showed the ultimate flexural load carrying capacity of mortar-filled bamboo specimens are higher than those of the conventional bamboo specimens. Specifically, mortar filled bamboo specimen with a diameter of 70 mm was significantly better, 41.10 and 47.06%, as compared than the conventional bamboo in terms of its flexural load carrying capacity for specimen without and with nodes, respectively. Increases in flexural load carrying capacity were also observed for the mortar-filled bamboo specimens having 80 and 90 mm diameter and these observed increases were recorded as 104.55 and 112.00%, and 48.72 and 60.74%, respectively for specimen without and with nodes. Furthermore, the deflection of mortar-filled bamboo elements are substantially greater than those of conventional. Finally, the advantages of the bamboo diameter and bamboo nodes on the flexural load carrying capacity indicated that these essential findings need to be carefully considered in designing structural elements for both mortar-filled and conventional bamboos.

In frame of global European standardization and as consequence of new knowledge concerning the existing bridge reliability, the need for revision of the Technological Standard No. 104 “Load-carrying capacity of road bridges and footbridges” [1] (hereinafter referred to as TS 104) had started up. In the first stage of the revision, the preparation and analysis in the form of Analysis Task (hereinafter referred to as AT) has been worked up by the collective of the Department of Structures and Bridges from the University of Zilina in cooperation with Slovak Road Administration (SRA), National Motorway Company (NMC) and other co-operators among academicians and designers. In the presented paper, the attention is paid to the general concept and basic assumptions of the AT and revised TS 104 for determining the road bridge load-carrying capacity.

Porous asphalt concrete (PAC) constitutes large air voids and coarse aggregate, forming a unique aggregate structure. The open pore structure is advantageous in creating space for stormwater runoff...

By integrating topology optimization and lattice-based optimization, a novel multi-scale design method is proposed to create solid-lattice hybrid structures and thus to improve the mechanical performance as well as reduce the structural weight. To achieve this purpose, a two-step procedure is developed to design and optimize the innovative structures. Initially, the classical topology optimization is utilized to find the optimal material layout and primary load carrying paths. Afterwards, the solid-lattice hybrid structures are reconstructed using the finite element mesh based modeling method. And lattice-based optimization is performed to obtain the optimal cross-section area of the lattice structures. Finally, two typical aerospace structures are optimized to demonstrate the effectiveness of the proposed optimization framework. The numerical results are quite encouraging since the solid-lattice hybrid structures obtained by the presented approach show remarkably improved performance when compared with traditional designs.

Solid construction certainly has a strong foundation that sustain Minimizing the potential for a settlement and the destruction of the foundation is so important to be known. So we should be able to know exactly how large a bearing capacity of the foundation. The purpose of this thesis is to redesign the foundation witha bore pile foundation. So in terms of knowing the size of the bearing capacity of the foundation, ,we discusses how the value of the bearing capacity of the foundation analytically which in this case using mayerhoff method, the from data SPT will using reese & wright method and mayerhoff method. The value of bearing capacity that we seek to determine the strength of the foundation that suffer a load the which is located thereon. legislative officebuilding Dharmasraya using a pile foundation and design with bore pile foundation, At the point BH-1 the carrying capacity of the single pile foundation is greater than the load, the foundation is said to be safe, Q permits> the rated load is 2000,32 tons > 47,973 tons. At point BH-2 the bearing capacity of the pile foundation of the group is greater than the load, the foundation is said to be safe, Q permits > 2073,532 tons > 1218,989 tons. At point BH-1 the carrying capacity of single bore pile foundation is greater than load carrying, the foundation is said to be safe, Q permit> the mean load is 1230,249 tons > 47,973 tons. At BH-2 point thecarrying capacity of the bore pile foundation is larger than the load, the foundation is said to be safe, Q permits> the rated load is 1222,337 tons > 1218,989 tons.

The dependence of load-carrying capacity on span length of beams, which contained a combination of normal strength concrete (NC) - High-performance fiber-reinforced concrete (HPFRC), was investigated in this study. The used HPFRC contained 1.0 vol.% long hooked blended with 0.5% short smooth fibers. Two types of span length were designed as 300 mm and 450 mm while dimensions of beam sections were identical with depth × width of 150 × 150 mm2. Each span included five types of partial structural materials as follows: Short 1 and Long 1 had no reinforcement with full of section using HPFRC, Short 2 and Long 2 had reinforcements with a full of section using HPFRC, Short 3 and Long 3 had reinforcements with a half of section using HPFRC at beam bottom, Short 4 and Long 4 had reinforcements with a third of section using HPFRC at beam bottom, Short 5 and Long 5 had reinforcements with a half of section using HPFRC at beam top. All beams were tested under three-point bending test. The shorter beam generally exhibited the greater load-carrying capacity than the long beam using same section type. The shear failure mode was dominant in case of the span/depth ratio less than 3. The HPFRC located at bottom of beam created the more effectiveness for enhancement of load-carrying capacity and stiffness of the beam, in comparison with the HPFRC placed at top of beam. The most effective zone of beam for HPFRC strengthening was at extreme tension fiber. Keywords: high-performance; composite beam; shear failure; bending resistance; load-carrying capacity.

In this research paper we are going to analysis the rear axle hosing of the tractor for circular, rectangular and elliptic shape to improving the structural stability and load carrying capacity, deformation and fatigue analyze done in FEA methodology, model designed in CATIA software.

The Canadian Highway Bridge Design Code (CHBDC) uses the concept of a target reliability index for evaluating the load carrying capacity of existing bridges. This index, which is based on risk to human life, relates to three aspects of uncertainties inherent in a bridge: (a) element behaviour, (b) system behavior, and (c) inspection level, where the inspection level currently refers to only manual inspections. Citing examples of tests on many instrumented bridges, the paper proposes an additional inspection level for inspections done with the help of electronic instruments and tests under controlled vehicle loads. The paper proposes simple additions to clauses of the CHBDC, for use when determining the optimum load carrying capacities of existing bridges where structural health monitoring information is available.

Cross-laminated timber (CLT) panels are widely used as structural members applied in a range of modern timber buildings. Changes in the load-carrying capacity of CLT walls after exposure to fire need to be discussed and summarized, but few studies have considered this due to a lack of available measurements and the prohibitive cost of performing the relevant experiments. To investigate the residual load-carrying capacity of CLT walls after fire, the multiple tests including axial compression tests under the ambient condition, standard fire tests and residual load-carrying capacity tests after fire were performed, and a numerical approach was developed in this study. The appropriate constitutive relationship and mechanical properties of timber affected by temperature were adopted, and the corresponding user-defined material subroutine was coded in ABAQUS and verified by typical examples. It was shown that the numerical models could reproduce adequately the failure process and mechanical behavior of the CLT specimens tested. The validated numerical method was used to carry out a parametric prediction that revealed the influence of the number of layers and the combustion time on the residual load-carrying capacity after fire. Moreover, the presented results could serve as a reference for the structural fire safety design of CLT structures.

When a partially exposed reinforced concrete beam deforms under tensile loading on reinforcements, the load-carrying capacity of the exposed reinforced concrete beam will significantly change, as the deformation of the exposed reinforcement bars and concrete do not follow a harmonising relationship. In this paper, the load-carrying capacity of a partially exposed reinforced concrete beam was investigated. By analysing a large quantity of test data, the changing patterns of the load-carrying capacity were obtained and two typical failure modes of the exposed reinforcement concrete were summarised. In the study, finite-element software was employed to simulate the test results. The simulated values were consistent with the test results. An extensive analysis of the influencing factors using a finite-element method was conducted. The length of the exposed reinforcement and the reinforcement ratio were considered as the controlling variables to obtain the changing failure modes of the exposed reinforced concrete beam. The analytical results confirmed the conclusions of a previous analysis.