Estimation Of Load Carrying Capacity Research Articles

Estimation of load-carrying capacity of cracked RC beams using 3D digital twin model integrated with point clouds and images

Digital twin (DT) is capable of managing, simulating, and future performance prediction of existing infrastructures by integrating three-dimensional (3D) geometric model and finite element (FE) model. This study aims to automatically generate geometric DT of existing RC members using point clouds and incorporate damages detected from images into FE models. An edge-based modeling method was proposed to extract sharp features for geometry reconstruction with incomplete point clouds, and an automated procedure was established for registering images to point clouds, mapping cracks detected in images to FE models, and assigning reduced material properties. Four RC beams were tested in a laboratory to validate the proposed method. Existing cracks were found to have a significant effect on structural capacity and failure mode. The results also showed that the developed FE model produced a good agreement between experimental and predicted failure loads while providing a more efficient and time-saving assessment protocol.

Numerical Analysis and Load-Carrying Capacity Estimation of Reinforced Concrete Slab Culvert Rehabilitated with a Grouted Corrugated Steel Plate

Two laboratory tests were conducted to investigate the mechanical properties and develop a load-carrying capacity estimation method for reinforced concrete (RC) slab culverts rehabilitated with a grouted corrugated steel plate (CSP). Subsequently, 216 numerical models of RC slab culverts rehabilitated with different shapes of CSPs and grout strengths were established to investigate the influence of these parameters and the arch effect on the rehabilitated system. A mechanical model was proposed based on the elastic center method, and a load-carrying capacity estimation method of RC slab culverts rehabilitated with grouted CSPs was established and verified. It was concluded that the load-carrying capacity of the rehabilitated system increased with a decrease in the radius of the side walls and crown at a constant radius of the CSP haunch. At a constant radius of the side walls and CSP crown, the load-carrying capacity of the rehabilitated system increased with an increase in the haunch radius. The most effective way to improve the load-carrying capacity of the rehabilitated system was to increase the radius of the haunches and reduce the radius of the arch crown and side wall. The arch effect of the grout was related to the load type. The load-carrying capacity of the rehabilitated system was the highest when the CSP was similar to or the same as the arch axes of the grout. The most important function of the grout was to provide strong lateral restraint for the CSP, reducing the required span and improving the load-carrying capacity of the CSP. In addition, the shear strength of the grout contributed to improving the load-carrying capacity by exerting an arch effect or experiencing shear failure. The proposed load-carrying capacity estimation method is applicable to rehabilitated systems with a box or arch-type CSP. Our findings provide guidance for engineers to design similar rehabilitated systems.

Evaluation of YLT method to estimate the load carrying capacity of one-way patched reinforced concrete slab under concentrated load

An unsaturated polyester resin (UPR) mortar was applied to repair the damage to the tension zone's one-way reinforced concrete (RC) slabs. The load carrying capacity of the patched RC slab is of interest to justify the effectiveness of the repair. The Yield Line Theory (YLT) may be used to estimate the load carrying capacity of patched RC slabs under concentrated load. The results of the YLT are compared with the experimental results to evaluate the validity of the YLT method. The results confirm that patching alters the yield line formation, mainly when the concentrated load is applied close to the patching zone. Subsequently, the YLT method provides a higher load carrying capacity estimation deviation for slabs with a loading point near the patching zone. On the other hand, the YLT method estimates load carrying capacity accurately when the loading point is away from the patching zone.

Limit analysis of masonry walls using discontinuity layout optimization and homogenization

AbstractA numerical limit analysis model for masonry walls subject to in‐plane loading is posed as a discontinuity layout optimization (DLO) problem, with the masonry conveniently modeled using a smeared continuum (“macromodeling”) approach and a homogenized yield surface. Unlike finite element limit analysis, DLO is formulated entirely in terms of discontinuities and can produce accurate solutions for problems involving singularities naturally, without the need for mesh refinement. In the homogenized model presented, masonry joints are reduced to interfaces, with sliding governed by an associative friction flow rule and blocks are assumed to be infinitely resistant. The model takes account of the interlock ratio of the masonry blocks, their aspect ratio and the cohesion and coefficient of friction of interfaces in both the vertical and horizontal directions. Results from the proposed model are compared with those from the literature, showing that complex failure mechanisms can be identified and that safe estimates of load carrying capacity can be obtained. Finally, to demonstrate the utility of the proposed modeling approach, it is applied to more complex problems involving interactions with other elements, such as voussoir arches and weak underlying soil layers.

Calculated estimation of load-carrying capacity of the main span beams of the E.O. Paton bridge across the Dnipro in Kyiv by nondestructive testing results

The Paton Welding Journal, 2022, №02. International Scientific-Technical and Production Journal «The Paton Welding Journal» «The Paton Welding Journal» has been published monthly since 2000 in English, ISSN 0957-798X. «The Paton Welding Journal» is a cover-to-cover English translation of the «Avtomaticheskaya Svarka» (Automatic Welding) journal. The «Avtomaticheskaya Svarka» journal has been published monthly since 1948 in Russian, ISSN 005-111X.

Ensuring the Passage of Freight Trains with Increased Axle Loads on Railway Bridges

Assessment of load-carrying capacity of metal and reinforced concrete railway bridges of different length built in 1930 - 2007, operated under modern heavy-weight trains, is considered in the article. To understand and cause the occurrence of deformations in structural elements, it is necessary to analyze the operation of bridge spans under conditions of increasing axial loads and traffic speeds. Deformation processes cause the appearance of defects, structural failures and accidents, which leads to material and environmental damage. The funds spent on bridge serviceability reconstruction are much more than those invested in protective measures. The main task is to study the interaction of bridges and rolling stock (bridge-train system), namely, the greatest influence from dynamic deformations and movements. The purpose of this work is to study the possibility of making way for heavy-weight rolling stock over the bridge spans. The research is based on the study of their load-carrying capacity estimation by test and classification methods. The paper presents the results of the measurements of the stress-strain state of bridge structures, obtained by the authors, using strain-measuring hardware-software complex (SMHSC). Depending on the results obtained, the decisions on the possibility of making way for heavy rolling stock with the axle load of 245-275 kN on the metal and reinforced concrete bridge spans are made.

Determination of load-carrying capacity of tank wagon with a loaded-friction spine girder

This article shows the results of load-carrying capacity estimation of tank wagon with lumber-friction backbar. The research was carried out on the basis of tank wagon model 15-1443-06, designed for transportation of light petroleum products. To determine the dynamic load-bearing structure of the tank wagon, a mathematical model, which takes into account its displacement during rocking motion. The connection between the supporting structure and running parts is described as the last pipeline connection. In this case the tank car is regarded as a system of three solid bodies - a load-bearing structure and two trolleys of model 18-100 with reshoring kits, which have stiffness and coefficient of wear resistance. The system of differential ratings of tank wagon's motion was developed by Runge-Kutt method under zero initial conditions. It was found that the maximum vertical acceleration, which acts in the center of mass of the load-carrying structure of the tank-car in the empty state is about 1.72 m/s2 (0,17g), which is about 20% lower than the acceleration of the standard structure. The main indicators of the strength of the load-bearing structure of the tank wagon were calculated. The method of joined elements, which is implemented in the SolidWorks Simulation (CosmosWorks) program complex, was used herewith. As lumped elements, we used spacious isoparametric tetrahedrons. The calculation was performed in quasi-statistics. It was found that the maximum equivalent loads occur in the area of the manhole placement are 173.7 MPa, which is 13% lower than in the standard structure. The conducted research will contribute to the creation of guidelines for the design of innovative structures of rail transport vehicles with improved technical and economic characteristics, as well as to increase the efficiency of the operation of rail transport

A novel strategy for the crossarm length optimization of PSSCs based on multi-dimensional global optimization algorithms

Prestressed stayed steel columns (PSSCs) offer a lightweight alternative for the design of slender compression columns. The stability of compression columns can be significantly enhanced by introducing crossarms. Previous research on this subject has primarily focused on load-carrying capacity estimation or analyses of the influencing factors of PSSCs. Thus, investigations of the design optimization of PSSCs remain scant. This work proposes a novel strategy for crossarm length optimization of PSSCs based on multi-dimensional global optimization algorithms. A multi-population genetic algorithm is introduced in the optimization process. The proposed optimization algorithm was demonstrated to be efficient and accurate in terms of determining the optimal crossarm length of PSSCs.

Determination of Load-Carrying Capacity of Railway Concrete Bridges According to New Guideline

The handbook "Determination of load-carrying capacity of railway bridges" [1] has grown up due to updating of old Slovak guideline [2] taking into account Eurocodes. In the case of railway bridges, there are about 2300 bridges in Slovakia and about 78 % of them are from concrete or masonry. About 28 % of bridge total number is older than 77 years and about 18 % of them are even older than 100 years. Therefore, there is need to make regular inspections, recalculate them – determine of load-carrying capacity and then to decide, which of them should be repaired or reconstructed [3,4]. The paper presents general concepts and basic assumptions for determining the load-carrying capacity of reinforced and prestressed concrete railway bridges. In contrast to design of a new bridge, additional data related to existing bridge condition and its behaviour like information from regular inspections and real state of degradation can be taken into account. Special recommendation and allowances for global analysis of existing concrete superstructures for the purpose of the load-carrying capacity estimation are discussed, as well.

Maximum Load Carrying Capacity Estimation of The Ship and Offshore Structures by Progressive Collapse Approach

Abstract The aim of the paper is to represent step by step progressive collapse analysis for maximum load carrying capacity estimation of a hull girder by using variant of Smith Method, named HULT by authors, with different element separation including single plates, stiffeners, hard corners and stiffened panels. The structural elements that form the ships and offshore structures are exposed to large vertical bending moments and especially compression or tension forces in the longitudinal axis in case of hogging and sagging under bad sea conditions. In recent years, it becomes very important and valuable to practically, fast and nearly correct estimation of the maximum vertical bending moment just before breaks in two (collapse) under the worst conditions. The optimum (accuracy, time, practicality) estimation of these values depend on how accurate the stress-strain relation of the structural elements are established. In this first part of study, the ultimate strength behaviour of the stiffened panels in decks, bottoms and sides is estimated by developed semi-analytical method with updated orthotropic panel calculation approach under uniaxial (only longitudinal axis) compression loads. The second part of calculation is focused on the progressive collapse analysis of hull girders under longitudinal uniaxial compression with Smith Method but with different element discretization in contrast to the conventional beam-column elements. Also some benchmark studies of such methods on ultimate limit state assessment of stiffened panels and nine benchmark hull girders of ships are conducted, using some candidate methods such as IACS Common Structural Rules (CSR), FEA with Ansys v13 and HULT prepared by authors. The results from the tests, FEM analysis and different computational approaches are compared to determine performance of the method.

Determination of Load-Carrying Capacity of Railway Steel and Concrete Composite Bridges

In the frame of global European standardization and in consequence of new knowledge related to existing bridges, the need for revision of the service handbook "Determination of load-carrying capacity of railway bridges" grown up. The paper presents general concepts and basic assumptions for determining the railway bridge load-carrying capacity. In contrast to design of a new bridge, additional data related to existing bridge condition and behavior like information from regular inspections and real state of degradation can be taken into account. Based on these data together with the remaining lifetime, a modification of reliability levels for existing bridges based on the mathematic theory of probability can be adopted in the evaluation process. Special attention is also paid to the specific features of determination of load caring capacity of steel-concrete composite bridges in exploitation. Recommendation and allowances for global analysis of existing composite steel and concrete superstructures for the purpose of the load-carrying capacity estimation are discussed as well.

Assessment of Cast-Iron Columns Using Analytical Models

The paper focuses on the assessment of cast-iron columns in industrial heritage structures. For cast-iron structures it is difficult to verify metallurgical composition and processing technology, which directly affect the geometry of cross-sections. The crucial issue of reliability of cast-iron structures is their brittle fracture in tension at higher slenderness ratios. The load carrying capacity of columns is affected by their stability and cast-iron strength in compression and tension. Outcomes of two recently proposed analytical models are compared with extensive experimental data and model uncertainty is quantified. It appears that the model is in a good agreement with experimental data and provides reasonably conservative estimates of load carrying capacity. Outcomes of the study may provide basis for foreseen improvements in calculating buckling coefficient according to ČSN 730038:2014.

Estimation of load-carrying capacity for thin-walled composite beams

The paper deals with thin-walled channel section beams made of composite laminates (epoxy resins reinforced with unidirectional long fibres). Two types of laminates have been analysed: carbon fibre reinforced polymer (CFRP) and E-glass fibre reinforced polymer. Thin-walled channel section beams subjected to pure bending in plane with the lowest second moment of area have been taken into consideration. Numerical and experimental investigations of columns loaded till failure have been performed. Also, models at the atomic level for analysing interactions between fibres and an epoxy resin have been prepared, and the obtained results have been correlated with a structural analysis of damaged beams. A comparison of the experimental results with the results of numerical simulations and the structural test results leads to a conclusion that tests allow one to predict the manner in which composite laminates are destroyed not only at the macro or micro, but also at atomic level. The above-mentioned experimental study permits the development of methods for estimating the ultimate load using numerical simulations.

Experimental estimate of Nγ values and corresponding settlements for square footings on finite layer of sand

Any structure constructed on the earth is supported by the underlying soil. Foundation is an interfacing element between superstructure and the underlying soil that transmits the loads supported by the foundation including its self weight. Foundation design requires evaluation of safe bearing capacity along with both immediate and long term settlements. Weak and compressible soils are subjected to problems related to bearing capacity and settlement. The conventional method of design of footing requires sufficient safety against failure and the settlement must be kept within the allowable limit. These requirements are dependent on the bearing capacity of soil. Thus, the estimation of load carrying capacity of footing is the most important step in the design of foundation. A number of theoretical approaches, in-situ tests and laboratory model tests are available to find out the bearing capacity of footings. The reliability of any theory can be demonstrated by comparing it with the experimental results. Results from laboratory model tests on square footings resting on sand are presented in this paper. The variation of bearing capacity of sand below a model plate footing of square shape with variation in size, depth and the effect of permissible settlement are evaluated. A steel tank of size <TEX>$900mm{\times}1200mm{\times}1000mm$</TEX> is used for conducting model tests. Bearing capacity factor <TEX>$N_{\gamma}$</TEX> is evaluated and is compared with Terzaghi, Meyerhof, Hansen and Vesic's <TEX>$N_{\gamma}$</TEX> values. From the experimental investigations it is found that, as the depth of sand cushion below the footing (<TEX>$D_{sc}$</TEX>) increases, ultimate bearing capacity and settlement values show an increasing trend up to a certain depth of sand cushion.

Analysis and Load-carrying Capacity Estimation of Existing Railway Filler-beam Deck Bridges

Abstract In the paper, the actual condition of several existing concrete railway bridges with encased steel beams is discussed. This structural type represents relatively often solution for small span railway bridges in Slovakia. The main conclusions from inspections and in-situ diagnostics are published together with the results of the loadcarrying capacity calculation on the basis of new European codes. Despite of well-known disadvantages, the bridges with filler-beam decks are still demanded by railway authorities because of their big stiffness and small construction depth.

Buckling Load Evaluation Method for Single Layer Cylindrical Lattice Shells

A rational design evaluation procedure is investigated for the elastic overall buckling load carrying capacity of single layer cylindrical lattice shell roof structures. The nature of the imperfection sensitivity of these structures is for the first time reviewed in this paper. This allows the development of the reduced stiffness buckling analytical concept for the lattice shells based upon the introduction of a simple lower bound estimation equation through the use of the so-called continuum shell analogy theory. The linear and nonlinear buckling loads found from conventional finite element analyses are compared with the present estimations. Finally, the elastic-plastic load carrying capacity estimation method through the use of the present elastic lower bound criteria is also proposed.

Load-Carrying Capacity Estimation Methods for Cold-Formed Steel Lipped Channel Member Using Effective Width Method

Distortional buckling may occur for Cold-formed thin-walled steel lipped channel member except local buckling and overall buckling. The buckling of flange and lip are the important factor for the occurrence the distortional buckling. The different design codes have different design method for calculating plate buckling coefficient of flange and lip using the effective width method. So the effective width method in different codes are introduced and the load-carrying capacities of 100 lipped channel section compressive members collected from reference are computed using ‘Cold-formed steel structures (AS/NZS 4600:2005)’, ‘Supplementary rules for cold-formed members and sheeting(EN1993-1-3:2006)’, ‘North American specification for the design of cold-formed steel Structural Members(AISI-S100:2007)’, ‘Specification for the design of cold-formed steel structural members (AISI:1996)’ and ‘Technical code of cold-formed thin-walled steel structures’(GB50018-2002). The calculated results show that ‘Technical code of cold-formed thin-walled steel structures (GB50018-2002)’ and ‘Supplementary rules for cold-formed members and sheeting (EN1993-1-3:2006)’ are conservative and ‘Cold-formed steel structures (AS/NZS 4600:2005)’, ‘North American specification for the design of cold-formed steel Structural Members (AISI-S100:2007)’ and ‘Specification for the design of cold-formed steel structural members (AISI:1996)’ are unsafe. The elastic buckling stress of different lipped channel sections are predicted by finite strip program (CUFSM) and get the suggested calculation formula of plate buckling coefficient of flange according to regression Analysis. The calculated results using suggested plate buckling coefficient of flange are agree to test results.

Estimation of load-carrying capacity of multi-layered plated structures

The load-carrying capacity of plated structures consisted of three-layered plates with metallic isotropic face layers and metallic or non-metallic orthotropic core is determined by means of four groups of methods, namely analytical–numerical methods, the effective width approach, numerical methods—finite element and finite strip methods as well as kinematical method based on principle of virtual velocities. Theoretical backgrounds of all applied methods are presented. Results of case studies concerning separated simply supported plate under compression and thin-walled girder under pure bending are discussed. Exemplary results of calculations are presented in diagrams. Some remarks derived from the comparative analysis of obtained results based on the methods under consideration are derived.

Stress–strain constitutive equations of concrete material at elevated temperatures

The paper presents a critical review of the currently available models for the mechanical behaviour of concrete at elevated temperatures. Based on these models and experimental data a stress–strain–temperature model is proposed which incorporates the effect of transient strain implicitly. This model can be easily incorporated into existing commercial finite element analysis software. A numerical example on a wall element heated on two opposite faces indicates that at very early stages of heating transient strain does not play an important part, but that as the exposure time increases the effect of ignoring transient strain progressively increases and produces unconservative estimates of load carrying capacity.

Highway bridge live loading assessment and load carrying capacity estimation using a health monitoring system

The Land Transport Authority of Singapore has a continuing program of highway bridge upgrading, to refurbish and strengthen bridges to allow for increasing vehicle traffic and increasing axle loads. One subject of this program has been a short span bridge taking a busy highway across a coastal inlet near a major port facility. Experiment-based structural assessments of the bridge were conducted before and after upgrading works including strengthening. Each assessment exercise comprised two separate components; a strain and acceleration monitoring exercise lasting approximately one month, and a full-scale dynamic test carried out in a single day. This paper reports the application of extreme value statistics to estimate bridge live loads using strain measurements.