Compressive Load Capacity Research Articles

Efficacy of Several Design Methods for Predicting the Axial Compressive Capacity of Piles

A variety of design methods for determining piles’ axial compressive load capacity are routinely employed in current practice. These range from methods specified in building codes to proprietary methods developed and employed by an assortment of engineering firms. In this study, the performance of eight commonly used design methods was evaluated using a database of 505 load tests and associated geotechnical design parameters compiled from Professor Olson’s database and that of the Iowa State Department of Transportation. The methods investigated included standard penetration test (SPT)-based methods, such as those recommended by the Federal Highway Administration (FHWA), U.S. Army Corps of Engineers, American Petroleum Institute, and Revised Lambda; and cone penetration test (CPT)-based methods such as those recommended by the Norwegian Geotechnical Institute, Imperial College, Fugro, and University of Western Australia. Pile capacities were calculated using APILE software and were compared with the measured capacities interpreted using the standard Davisson criterion and stored in the databases. The performance of all design methods was evaluated in relation to accuracy, precision, effect of soil type, diameter, and length. Both SPT and CPT methods exhibited similar accuracies, however, CPT-based design methods exhibited significantly better precision compared with SPT-based methods. All methods had shortcomings and appeared to work best under certain conditions, which are documented in this paper. The authors believe that this evaluation will permit practicing engineers and regulating bodies to better understand the efficacy of various design approaches in common use.

Comparative analysis and applicability of corrosion test methods for construction steel components

In this paper, a systematic study of different methods of manufacturing corroded components and their post-corrosion morphology has been carried out to verify the effectiveness of different accelerated corrosion testing methods. Corrosion tests were performed on specimens of construction steel Q345 by three corrosion methods, i.e., atmospheric exposure corrosion, salt spray accelerated corrosion, and accelerated electrochemical corrosion. The surface morphology of the specimens after corrosion was measured, the characteristics of the corrosion morphology development of the various corrosion methods of the components were analyzed, and the corresponding probability model of the corrosion morphology distribution was developed. Accordingly, a random corrosion surface modeling technique was developed based on the fast Fourier transform and two-dimensional digital filtering techniques, and the mechanical analysis of axially pressed components with different corrosion surfaces was carried out. The results indicate a clear difference in the undulation and variation pattern of the corroded surface under different corrosion methods. However, the disparity in the axial compression load capacity of the specimens under different surface conditions were minimal, was less than 1%. Therefore, the axial compression performance of corroded steel members can be studied using electrochemical corrosion and smooth corrosion surface simulation in the future study.

Dynamic analysis model of open-ended pipe piles that considers soil plug slippage

The high-strain dynamic load test (HSDT) is a convenient and efficient method of assessing the compressive load capacity of piles. Although several numerical models are available to interpret the responses of open-ended pipe pipes (OEPPs) in the HSDT, these models cannot capture the motions of pile base soil or distinguish the difference in the external and internal soil resistance of the OEPPs. Thus, a novel fictitious-soil pile (FSP) model is developed in this study to analyze the responses of small-diameter OEPPs with soil plugs under high-strain impact loading. Apart from simulating the wave propagation in the base soil and slippage at the pile–soil interface, the proposed model also describes the sliding modes of the soil plug under dynamic load conditions (DLCs). The developed model was validated by comparing the calculated pile responses with those obtained from conventional numerical models as well as field measurements of a steel OEPP. Based on the proposed model, two sliding modes of the soil plug (bottom- and top-sliding) were found in the HSDT to be dependent on impact loading durations. The prediction of the OPEE load capacity from HSDTs could be affected by the soil sliding mode, which should be investigated in more detail in future research.

Mechanical properties of BFRP-reinforced glued laminated wood hollow round column under eccentric pressure

The FRP-wood column elements are lightweight and high performance, meeting the social demand for sustainable construction. In this study, a basalt fiber reinforced polymer (BFRP) reinforced glued laminated wood hollow round column structure is proposed. Small eccentricity compressive tests and numerical simulations were carried out on glued wood hollow columns strengthened with BFRP to study the effect of BFRP arrangement on the mechanical properties of glued wood hollow columns with constant material, size and eccentricity. All samples are compression side of the wood first yielded, and then some samples tensile side of the end of the wood fracture or the central section of the wood was pulled off, which belongs to the typical compression bending failure and conforms to the characteristics of small eccentric compression. The compressive load capacity of the wood column after BFRP pasting was increased by 3.4%∼30.54%, and the lateral flexural stiffness was increased by 1.44%∼23.86%. Meanwhile, pasting BFRP at the end and middle of the wood column can effectively restrain the compression deformation at the end and bending deformation at the middle, and obtain higher load capacity and lateral flexural stiffness. The numerical simulation results agree well with the experimental results and can effectively characterize the mechanical properties of BFRP-reinforced glued laminated wood hollow round column under eccentric loading conditions.

Compressive behaviour and prediction model for short and slender FRP-confined GFRP bars

Glass fibre reinforced polymer (GFRP) composite bars can be used as internal reinforcement for concrete structures built in harsh environmental and service conditions. Their utilisation as longitudinal reinforcement for compression members is not widely recommended though due to the anisotropic nature of FRP, their complex failure modes, and limited research, especially for slender bars. A more recent innovation has resulted in the wrapping (confinement) of GFRP bars with FRP composites oriented in the hoop direction. These confined bars have demonstrated promising improvement in FRP bar compressive behaviour and ductility. In the current study, the experimental compressive behaviour of eighty short and slender FRP-confined GFRP bars is reported and a compressive strength model is proposed. The experimental parameters investigated are (i) wrapping layers (i.e. one, two, and three layers oriented ± 83.3° to the longitudinal axis of the bar), and (ii) slenderness ratios (i.e. 15, 30, 45, and 60). The resulting compressive load capacity and strength, stress–strain behaviour, and failure modes are then reported for each tested bar. Test results indicate that an increase in slenderness results in decreased strength. In addition, failure modes shifted from splitting to buckling of the longitudinal fibres. GFRP bars with at least two winding layers had a significantly higher compressive strength than the control GFRP bar (not including winding) and they also exhibited bi-linear stress–strain behaviour as well as ductile failure modes. A compressive strength prediction model is then developed, which is based on the modification of the Johnson-Euler buckling theory and correlates well with the experimental results. The research presented herein has the potential to contribute to the development of design guidelines for concrete compression members, such as columns, piers and piles, that are reinforced with FRP-confined GFRP bars.

Use of steel wire mesh for compressive strength enhancement of AAC masonry wall

Autoclaved aerated concrete (AAC) is an alternate building block but possess a low compressive strength in comparison to the traditional burnt clay bricks. Past earthquakes have shown that the seismic capability of the masonry walls, particularly using low-strength blocks are very weak, and thus strengthening of this masonry is necessitated. Wire mesh is one of the most common and cost-effective strengthening materials. Wrapping the entire surface of the wall with wire mesh is the most adopted technique. However, in large-scale construction, it is un-economical. Thus, the present study investigates the behaviour of AAC masonry wall by embedding the steel wire mesh at the bed joint and bed-head joint of the masonry course. Two types of wire mesh, i.e., (a) chicken wire mesh (CWM) and (b) welded wire mesh (WWM) were employed for the strengthening. Wire mesh was alternately installed at the bed joint of the course of the masonry and subsequently installed at the bed-head joint of the course with proper anchorage using a U nail. The results show that strengthened wall specimens improve the compressive load capacity, energy dissipating capacity, ductility, and stiffness, as well as significantly improving the abrupt failure of the wall specimens. Bed-head joint strengthened specimens outperform the bed joint strengthened specimens in terms of capacities.

Analysis of Non-Destructive Indicating Properties for Predicting Compressive Strengths of Dendrocalamus sericeus Munro Bamboo Culms

Bamboo is a natural material with the potential for being used in sustainable construction. However, uncertainty in the bearing capacity of the bamboo results in nonstandard values for structural engineering design. This research studied the simple and multiple linear regression analyses for indicating properties to predict the axial compressive load capacity and strength of bamboo culms, which will be useful information for quality control during building construction and further structural grading. First, twelve basic physical properties were measured from 111 samples of Dendrocalamus sericeus Munro bamboo culms, and axial compressive load tests of the bamboo culms were performed. Then, the correlation significance of the physical properties to axial load capacity and strength (load per area) were analyzed by the Pearson correlation method. The results show that five parameters, i.e., linear mass, culm wall thickness, external diameter, moisture content, and density, were statistically significant with the responses (compressive load capacity and compressive strength) and then defined as "candidates for indicating properties". Next, simple linear and multiple linear regression were analyzed to formulate the relationship between the significant indicating properties and the responses. From the simple linear regression analysis, linear mass can be best used as an indicating property for predicting the maximum compressive load. The maximum compressive strength was well associated with density. The multiple linear regression analysis shows an improvement in the response predictions with respect to the simple linear regression analysis with the higher R2-values. Finally, structural grading of the bamboo is determined.

Experimental studies and analysis on axial compressive properties of full iron tailings concrete columns

The structural properties of iron tailings must be verified for them to be used in reinforced concrete structures. In this study, finely ground iron tailings powder was used as an admixture, and iron tailings gravel and iron tailings sand were used as the coarse and fine aggregates, respectively, to prepare full iron tailings concrete (FITC), which was compared to conventional concrete (CC). Eight concrete column specimens comprising different raw materials were cast. Three slender and three short reinforced FITC columns were designed, tested under axial compression, and compared to the experimental results of the CC columns. The load-bearing and deformation capacities of FITC columns were investigated for the first time. The results indicated that the incorporation of iron tailings reduced the strength and modulus of elasticity of FITC by 7.1–8.8 % and 18.2–19.1 %, respectively. The bearing capacity of three FITC slender columns was 4.6–8.7 % less than that of the CC slender column, and the bearing capacity of three FITC short columns was 10.0–16.7 % less than that of the CC short column. The bearing capacity calculations of the FITC columns indicate that they are safe as per existing Chinese and ACI standards. However, their ductility and stiffness are inferior to those of CC columns. A calculation model for the axial compressive load capacity of FITC columns, which agreed with the test results, was selected.

Axial compression capacity of rectangular CFST columns under random pitting corrosion

To study the effect of random pitting corrosion, this paper presents the change law of the bearing capacity of the rectangular concrete-filled steel tube (CFST) column under the action of axial force with the mass loss ratio of the outer steel tube. Existing experimental data, including the axial ultimate bearing capacity and load displacement curves of the uncorroded and corroded rectangular CFST columns, are collected to verify the rationality of the finite element model. ANSYS software was used to establish a model that can simulate the pitting corrosion, and the results of the finite element analysis were compared with the experiment, which illustrates that the established model can accurately predict the actual load changes. For further research, the corroded thickness tc/t, which include constant tc/t and random tc/t, and other influencing factors such as corrosion pit diameter Dc, steel tube wall thickness t, material strength, shape and section size of specimens are discussed, the results reveal the effect of these parameters on the decline of axial compressive load capacity. Meanwhile, to visually reflect this effect, this study introduces the concept of bearing capacity reduction coefficient Rcs and Rc to express the ratio of bearing capacity of specimens before and after corrosion. The extensive stochastic finite element analysis was carried out, and on this basis, a suitable calculation formula for the reduction factor is proposed to predict the axial compression bearing capacity of the corroded rectangular CFST column by measuring the value of local mass loss ratio of the outer steel.

Experimental and numerical studies of concrete-filled corrugated steel tubular column under axial compression

This paper proposed a novel composite structure of concrete-filled corrugated steel tubular column with polygonal steel tubes (CFCST-PST), which consisted of concrete and multi-cell steel tubular column, includingpolygonalsteeltubesandcorrugatedsteelplates. This new column enables the confinement of multi-cell steel tubular column to the core concrete in addition to preventing local buckling of the tubes. To investigate the axial compression mechanical properties of the column and the capabilities of polygonal steel tubes, a concrete-filled corrugated steel tubular column with square steel tubes (CFCST-ST) was designed and fabricated as a comparative specimen. Axial compression experiments and finite element studies (FEM) were carried out on both CFCST-PST and CFCST-ST specimens. Through the previous research, it was found that CFCST-ST has better ductility and higher bearing capacity, while the corrugated plate with higher lateral stiffness, so that concrete is well restrained. In this paper, research had revealed that CFCST-PST effectively expands the strongly confined area of core concrete, as compared to CFCST-ST. A detailed discussion of the strain development of the corrugated plates was presented in order to demonstrate the confinement effect. Finally, the method of confining stress homogenization was used to establish formulas for calculating the axial compression load capacity of CFCST-PST for engineering purposes.

Analysis of influencing factors on axial compression performance of BFRP bars-coral reef and sand concrete columns

A more systematic analysis of the factors influencing the axial compression performance of basalt-fiber-reinforced polymer (BFRP) bars-coral reef and sand concrete (CRSC) columns was carried out based on axial compression load capacity tests on 15 columns in 5 groups. The test study factors include the concrete strength, longitudinal bars diameter, stirrup spacing, slenderness ratio and bars type, and type of bars material. The results show that the damage process of BFRP bars-CRSC columns can be divided into elastic stage, cracked stage and damage stage. Under different diameters of longitudinal bars, increasing the diameter of longitudinal bars leads to the reduction of the adhesion between longitudinal bars and concrete protective layer, which reduces the load-bearing capacity; decreasing the spacing of hoop bars helps to improve the ductility of the member, but it also reduces the continuity of CRSC and the strength.

The Eccentric Compression Performance of Spirally Stiffened Thin-Walled Square Concrete-Filled Steel Tubular Laminated Composite Members

To enhance the local buckling resistance of thin-walled steel pipes and enhance their fire and corrosion resistance, a new spirally stiffened thin-walled square concrete-filled steel tubular laminated composite member with transverse ribs is proposed. Through the four forms of combined members for eccentric pressure testing, it was found that: ordinary thin-walled steel pipe concrete drum buckling is more severe; with spiral ribs, the buckling is limited between the stiffening ribs; and the deformation is significantly reduced. By addressing the problem of cooperative work between the inner and outer structural layers of new components, it was found that, after setting constraints such as steel bars, the integrity of the two can be ensured, and the stress performance is significantly improved; compared to ordinary steel pipe concrete, the load-carrying capacity is 17.9% higher, and the deformation capacity is roughly equivalent. Spiral ribs as a new form of spatial restraint, in addition to increasing the local bending stiffness, manifest an overall restraint role in limiting lateral deformation of the steel pipe, whereas the role of vertical stiffness is insignificant. Based on test evidence, the influences of the width to thickness ratio of spiral ribs and pitch were determined, and reasonable structural measures for the members were given. Through the N–M relationship curve, the limit of damage in compression and tension under eccentricity was obtained at an eccentricity of about 0.9. Finally, a method for calculating the eccentric compressive ultimate load capacity of this new composite member was proposed.

Metalized Plastic Waste Fiber Effects on Green Concrete Beams Mechanical Performance

In a year, millions of forms of plastic are produced, and approximately, half of the generated plastics are used once only. Incorrect and insufficient management of these waste materials causes adverse effects on the nature of the soil, water, humans, and animals’ life. One type of waste plastic is metalized plastic waste (MPW), which is used mainly in different types of food packaging productions, and there is no appropriate technology for reusing it all over the world. In this paper, the effect of MPW as a fiber by 0.5% and 1% on compressive, flexural load capacity, and toughness of green concrete containing 7.5% and 15% silica fume or natural zeolite in Oman Sea tidal zone environment at 28, 90, and 180 days was investigated. The results indicate that by adding the MPW fiber, the compressive strength and maximum flexural load capacity of green concrete were decreased 25% and 15%, respectively. Meanwhile, the effect of MPW fiber on concrete containing 15% silica fume was greater than 7.5% silica fume concrete. Flexural toughness of natural zeolite concrete containing 0.5% MPW fiber was up to 510.9% greater than the observed one. Moreover, the toughness of green concrete containing 1% MPW fiber and zeolite was up to 35% greater than 0.5% MPW concrete. Meanwhile, the effect of MPW fiber on flexural toughness of concrete containing 15% natural zeolite was greater than 7.5% natural zeolite concrete.

Axial behavior of RC column strengthened with laterally reinforced FRHPC jacket

AbstractThis paper is aimed to examine the axial compression performance of reinforced concrete (RC) base column specimens strengthened by fiber‐reinforced high‐performance concrete (FRHPC) jackets using the enlarged cross‐section method. For this purpose, the axial compression performance test is performed on one un‐strengthened column and four strengthened columns to assess the effects of FRHPC jacket thickness, whether the jacket was configured with stirrup and the spacing of stirrup were considered. Based on the theory of confined concrete and the FRHPC principal structure relationship, a theoretical calculation model is also established to explore the axial load‐carrying capacity of the columns. The test results indicate that an increase of the cross‐sectional reinforcement of the FRHPC jacket can enhance the axial compression load capacity and ductility of the columns. Furthermore, an increase in the FRHPC jacket thickness leads to the growth of the load capacity; however, there is no significant increase on the ground of its ductility. The addition of stirrup in the FRHPC jacket can improve both load capacity and ductility of the columns such that the smaller the spacing of the stirrup, the greater the increase of both load capacity and ductility. The predicted results by the proposed model are in good agreement with those of the tests.

Response of thin flexible compression columns with self-reacting lateral constraint

The study investigates the effects of self-reacting lateral constraint on the compression load capacity of thin composite columns. A dynamic finite element analysis model is developed to aid in the optimization of the column lateral constraint which leads to a 50-fold increase in load capacity over the first critical buckling load. First, the model is compared against known analytical solutions for a column buckling between bi-lateral constraints. Next, the constraints are made to float and self-react, and the model is developed to study the role of column geometry, material properties, and initial gap between the column and lateral constraint on post-buckling response. Experiments are conducted over a wide range of column lengths and gap thicknesses and the load-deformation response including snap-through buckling loads, and buckling modes are measured and compared to model predictions. It is shown that the load capacity of thin composite columns can be increased to an upper bound governed by the membrane compressive strength of the column by using optimal constraint conditions.

Numerical analysis of eco-friendly ductile cementitious composite influence on structural masonry reinforcement

The behaviour of structural masonry walls reinforced with a ductile sustainable cementitious coating, called Eco-friendly Ductile Cementitious Composite (EDCC) is evaluated through Finite Element Modelling (FEM). EDCC is a sustainable material composed mostly by fly-ash and sand, with low cement content, used to repair masonry structures: it has excellent ductile behaviour due to the presence of polymeric fibres. Numerical models that can accurately simulate EDCC-reinforced masonry behaviour under compressive, flexural and shear loads were validated using previous experimental tests. A literature review was completed about the parameters defined for the component materials, interfaces and strategies that can be implemented to model structural masonry walls accurately, with the finite element method. Subsequently, the models were calibrated, comparing the results of stress vs strain or force vs displacement diagrams of experimental tests with numerical simulations. The models were able to simulate the masonry behaviour, with consistent results and failure modes. Parametric modelling was implemented to develop a formula capable of predicting the compressive load capacity of masonry walls strengthened with EDCC.

Compressive and shear strength of cob wallettes reinforced with bamboo and steel mesh

In the present study, a novel experimental programme is conducted to evaluate the compression and shear behaviour of cob wallettes reinforced with bamboo and steel mesh. Three major categories of wallettes were prepared comprising at least three samples for each type for both compression and shear tests. The first category comprises four types of samples: unstabilised, unreinforced cob wallettes (USURCWs), cement-stabilised cob wallettes (CSCWs), coir-fibre-reinforced cob wallettes (CFRCWs) and straw-fibre-reinforced cob wallettes (SFRCWs). In the second and third categories, similar sample types as included in the first category were reinforced with bamboo and steel mesh, respectively. Five per cent fibres and 10% cement (by dry mass of soil) was added to the respective dry soil mixes followed by addition of 33.7% water and thorough mixing. Test results showed that the addition of fibre, cement and bamboo or steel reinforcement prevents brittle failure. Fibre-reinforced samples showed improvement in compressive and shear load capacity by about 5 to 33% and 78 to 107%, respectively, with respect to the USURCWs. Both fibre and cement stabilisation enhance the deformable property of wallettes compared to unreinforced ones. Overall, steel reinforcement exhibited higher load capacity, strength and deformability as compared to bamboo-reinforced samples and samples without bamboo or steel reinforcement. Compressive and shear strength results obtained satisfy the design requirement prescribed in the 1998 New Zealand standard NZS 4297, with the exception of USURCWs and USURCWs reinforced with bamboo mesh.

Beton-dolgulu çelik tüplü kompozit kısa kolonların nihai yük taşıma kapasitesinin ilgililik vektör makinesine dayalı tahmini için modelleme yaklaşımı

In this paper, the applicability of relevance vector machine (RVM) has been explored to predict the ultimate axial load capacity of concrete-filled steel tube composite stub columns (CFSTCSCs) with circular sections under axial compression loadings. As an extension of support vector machine, RVM employs Bayesian inference to achieve parsimonious solutions for regression and classification. By using MATLAB software and 150 comprehensive experimental data presented in the previous studies, a model to predict the ultimate load of circular CFSTCSCs was developed by properly training the data. Utmost care has been taken in grouping the data for training and validation. About 80% dataset for training and 20% dataset for validation have been used, respectively. The results show that the predicted ultimate axial compression load capacity of CFSTCSC members is comparable with that of the corresponding experimental data and the percentage difference is about ∓11%.

Coupling effect assessment of vacuum based pozzolana slurry encrusted recycled aggregate and basalt fiber on mechanical performance of fiber reinforced concrete

To deal with the rapidly increasing construction and demolition (C&D) waste, the use of eco-friendly and resource efficient concrete in structural applications has become greatly essential for the modern-day construction industry that emphasizes on green environment and sustainability. In this regard, the applications of recycled concrete aggregate (RCA) in place of virgin aggregate can be of great profitable use however, its inferior quality and lower mechanical properties are the major challenges which limit their practical adaptation. To augment the mechanical performance of RAC and promote its structural applications, we applied a new eco-friendly and effective strength-enhancing technique that involves synergistic use of vacuum-based encrusted RCA and fiber reinforcing technique. The performance of this new technique is assessed for two types of RAC containing 20% and 100% of pozzolana slurry treated RCA and reinforced with 0%, 0.25%, 0.5%, and 1% volume fractions of basalt fiber (BF) with regards to various physical and mechanical properties. The compressive loading capacity, splitting tensile strength and flexural strength of BF reinforced 20TRAC formulation reveal maximum improvement of 16%, 24% and 57%, respectively, while that of BF reinforced 100TRAC formulation show maximum enhancement of 8%, 18% and 37%, respectively. Furthermore, the microstructure study revealed improved concrete matrix quality and excellent bonding between BF and host concrete matrix. The ultrasonic pulse velocity and water absorption increased with increase in the BF dosage. Lastly, the correlation analysis for various physical and mechanical properties is presented that depicts an excellent relationship with a correlation factor of greater than 0.9. Conclusively, the composite addition of vacuum-based pozzolana slurry treated RCA and BF constitutes better microstructure and thereby is able to upgrade the mechanical performance of fiber reinforced recycled concrete.

Optimizing compressive load capacity for differing tensegrity geometries

Tensegrity structures present new possibilities to the field of structural engineering, owing to their ability to efficiently distribute compressive loads associated with their non-orthogonal design. Previous research has shown that when pretensioned, tensegrities exhibit higher resistance to compressive loading. However, over-tensioning can have adverse effects, reducing the tensegrities overall resistance to compressive loading. The geometry of a tensegrity affects how the structure reacts to loading, and the prestress and loading can concurrently affect geometry. This paper uses genetic algorithms to optimize the pretension loads in the cables of a tensegrity to deliver the highest overall vertical load capacity. The results are applied to determine the ultimate load-carrying capacity of tensegrities under a compressive load and determine the optimal aspect ratio at which this is achieved. By optimizing the pretension, the tensegrity can withstand compressive loads up to six times those that have been previously reported in literature.