Calculation Formula Of Bearing Capacity Research Articles

Shear Property and Uniform Vertical Load Capacity of Bamboo I-Beams

Bamboo oriented strand boards (BOSB) are very suitable for application in construction structures because of their excellent mechanical properties. This research investigated the shear performance of bamboo I-beams composed of BOSB to verify the structural performance of I-beams. Short beam shear tests and uniform vertical load capacity tests were performed to investigate the effects of various factors on the properties of bamboo I-beams. The results showed that shear bearing capacity and uniform vertical load capacity of bamboo I-beams exceeded the requirements for performance-rated I-Joists in APA PRI-400-2021. The shear bearing capacity, stiffness, and failure types of bamboo I-beams were determined by the web materials, flange–web joint type, and beam depth. Increasing the bamboo I-beam depth without changing the flange dimensions had no significant effect on the shear bearing capacity and stiffness of bamboo I-beams. The shear bearing capacity and stiffness of wooden orientated strand board webbed I-beams were almost half of those of bamboo I-beams with the same depth. The shear bearing capacities of specimens calculated based on the shear bearing capacity calculation formula of I-beams recommended in the Canadian standard were reasonably close to the experimental results. The uniform vertical load capacity of bamboo I-beams gradually decreased as the depth of the bamboo I-beam increased from 300 mm to 500 mm.

Bearing characteristics and failure mechanism of a novel plate-short anchor structure for tunnel crack reinforcement

In order to solve the problem of tunnel diseases caused by lining cracking in mountain tunnels, this paper studies the crack repair technology of mountain tunnels. Based on this, this paper innovatively puts forward a new repair method of tunnel cracks—plate-short anchor assembly structure. Through literature investigation and theoretical derivation, the mechanical mechanism of the plate-short anchor assembly structure is analyzed, and the calculation formula of bearing capacity is proposed. The loading device for the bias pressure test of prototype components of tunnel lining is independently designed, and the destruction test is successfully carried out by simulating the stress mode of tunnel lining. By simulating the state changes of the plate-short anchor assembly structure under different cracking states, the ultimate bearing capacity under different working conditions is obtained, and the evolution process of the failure mode of the new structure is revealed.

Experimental and numerical research on seismic behavior and shear capacity of SRC column-RC beam composite joints

The seismic behavior of SRC column-RC beam composite joints was investigated experimentally and numerically. Based on the analysis of experimental results, it was considered that the joints were subjected to flexural failure and shear failure in the connection zone, and the stirrup ratio in the connection zone would affect the failure mode. The ductility and energy dissipation capacity of the joints were between the ordinary RC joints and SRC joints. The structural measures of setting ring beams in the connection zone were put forward to improve the characteristics of bearing capacity and ductility asymmetry. The change of concrete grade has little effect on the joint strength, but the increase of the axial compression ratio would significantly reduce the bearing capacity of the joints. When the axial compression ratio was greater than 0.5, it was speculated that the joints would be damaged in other forms. According to the analysis of the shear proportion borne by various components, it was considered that the shear bearing capacity of composite joints was mainly borne by stirrups, steel webs and concrete in the connection zone. Based on the strength superposition method, the shear bearing capacity calculation formula of the joints was established by considering the adverse effect of the axial compression ratio and ignoring the shear contribution of flexural failure concrete.

The bearing capacity analysis of limestone strata roof containing a shallow-buried cylinder Karst cave

The chief objective of the article is to investigate the bearing capacity of limestone strata roof containing a shallow-buried cylinder Karst cave. Firstly, taking into account the characteristics of Karst landform in China, a spatial axial-symmetrical model was established. Concurrently, the general solution of stress components was gained using Love displacement method. Subsequently, combining failure mechanism of ground collapse and the expressions of stress components, the bearing capacity calculation formula was determined. Finally, based on practical engineering, a comparison of calculation result indicates the error is less than 3.5%, which meets the proposal standard necessity in practice.

Mechanical properties of modular prefabricated steel-concrete composite internal joints under cyclic loading

To investigate the influence of the key parameters on the mechanical properties of modular prefabricated steel-concrete composite internal joint (MPCIJ), finite element model (FEM) of MPCIJ under cyclic load was established by using the finite element analysis (FEA) software ABAQUS, based on test results. FEA results were then compared with the test hysteresis curves, skeleton curves, and failure mode. Based on the verification of reliability of the numerical model, the influence of different parameters on the structural performance was analyzed. According to test and FEA results, the MPCIJ shear mechanism and bearing capacity calculation formula were proposed. Results showed that MPCIJ bearing capacity and deformation performance increased with increasing axial compression ratio (n < 0.45), however, the increase was within 5%. With the increase of concrete strength, the joint bearing capacity and fire resistance and corrosion resistance of joint modules were effectively improved. The recommended width/thickness ratio of the square steel tube should not be less than 17. Reducing the distance between the bolt edges could improve the plastic deformation of the joint module with the recommended value of 25–35 mm. The bolt hole diameter increase should be between 1.5 and 2 mm. MPCIJ bearing capacity increased with increasing thickness of joint cover plate and the peak load increased by about 17%; however, the shear deformation inside the joint module also increased. The shear mechanism of MPCIJ is the ‘steel plate shear wall’ and ‘T-shaped steel frame’. The correctness and reliability of the MPCIJ shear capacity formula were verified.

Residual behavior of recycled aggregate concrete beam and column after elevated temperatures

This paper presents the results of an experimental study on the residual behavior of reinforced recycled aggregate concrete (RRAC) beam-columns after exposure to elevated temperatures. Two parameters were considered in this test: (a) recycled coarse aggregate (RCA) replacement percentages (i.e. 0, 30, 50, 70 and 100%); (b) high temperatures (i.e. 20, 200, 400, 600, and 800℃). A total of 25 RRAC short columns and 32 RRAC beams were conducted and subjected to different high temperatures for 1 h. After cooling down to ambient temperature, the following basic physical and mechanical properties were then tested and discussed: (a) surface change and mass loss ratio; (b) strength of recycled aggregate concrete (RAC) and steel subjected to elevated temperatures; (c) bearing capacity of beam-columns; (d) load-deformation curve. According to the test results, the law of performance degradation of RRAC beam-columns after exposure to high temperatures is analyzed. Finally, introducing the influence coefficient of RCA replacement percentage and high temperatures, respectively, to correct the calculation formulas of bearing capacity of beam-columns in Chinese Standard, and then the residual bearing capacity of RRAC beam-columns subjected elevated temperatures is calculated according to the modified formulas, the calculated results are in good agreement with the experimental results.

EXPERIMENTAL STUDY ON SHEAR PERFORMANCE AND BEARING CAPACITY OF PRESTRESSED CONCRETE T-BEAMS

Prestressed concrete t-beams have complex shear mechanism, and their shear performance is influenced by various factors, such as flange width and prestress. The shear performance of prestressed concrete t-beams has not been solved completely. This study designed and established nine prestressed concrete t-beams and one ordinary reinforced concrete t-beam to investigate the influence of flange width and the number and bending angle of prestressed tendons on the shear bearing capacity of concrete t-beams. The crack development, failure form, mid-span deflection, and concrete strain of the prestressed concrete t-beams were measured to analyze the load–deflection relationship; the concrete strain in the compressive zone; and the shear bearing capacity under different flange widths, reinforcement ratios of prestressed tendons, and bending angles. Experimental results were verified by the outputs of the bearing capacity calculation formula specified in China, America, Canada, and Europe. The results demonstrate that the increase in flange width, bending angle, and number of prestressed tendons can improve the internal force and shear bearing capacity of t-beams significantly. However, the flange width has less evident influence on the shear bearing capacity. The positive effect of the flange is evident under a specific flange width. For example, when the ratio of the flange width to the web width is greater than 4. The shear bearing capacity of the prestressed concrete t-beams is large when the reinforcement ratio and bending angle of the prestressed tendons are great. This study has reference values for revealing the shear failure mechanism of prestressed concrete t-beams under concentrated loads and provides a basis for engineering design. Keywords: Prestressed concrete; T-beam;Shear bearing; Experimental study

Mechanical properties analysis of Angle steel connector of composite bridge with corrugated steel webs

The finite element software Midas FEA was used to simulate and calculate the ultimate bearing capacity, von Mises stress and load-slip curves of the Angle steel connector specimen of the composite bridge with corrugated steel webs. And the ultimate bearing capacity obtained by numerical simulation is compared with the calculated value of the bearing capacity of Angle steel connectors in each specification. The results show that when the ultimate bearing capacity of the specimen is reached, most of the Angle steel is in a state of buckling, all the steel bars are in a state of buckling with deformation, and the concrete pin in the hole is partially damaged. In the specifications, the calculation formula of bearing capacity of Angle steel connector is conservative, the main reason is that the influencing factors of ultimate bearing capacity of Angle steel connector are not comprehensive enough, and the existing formula needs to be further revised.

Mechanical behavior and bearing capacity calculation of self-stressing steel slag aggregate reinforced concrete filled circular steel tube columns

To study the mechanical mechanism of self-stressing steel slag aggregate reinforced concrete filled circular steel tube (steel slag aggregate/concrete@circular steel tube) columns, eight specimens including six short columns and two intermediate length columns were designed for axial compression test, the variable parameters, such as the diameter-thickness ratio, expansion rate of steel slag aggregate concrete and length-diameter ratio were considered. The whole failure process of specimens was observed, and then the strain-stress curves as well as the peak stress was obtained. The influence of variable parameters on the mechanical behavior of self-stressing steel slag aggregate/concrete@circular steel tube columns was analyzed. Test results indicate that the short columns under axial load exhibit shear failure while the intermediate length columns experience global flexural buckling failure mode. The stress-strain curves of all specimens are basically similar, which undergo the peak point, descending section, slow rise section and so on. The peak strain and peak stress of all specimens are significantly increased compared with those of common steel slag aggregate concrete, and the improvement effects are more obvious in short columns than those in intermediate length columns. According to the limit equilibrium condition and entire process analysis, the calculation formula of bearing capacity of self-stressing steel slag aggregate/concrete@circular steel tube columns was proposed, and then the stress-strain model of self-stressing steel slag aggregate/concrete@circular steel tube columns was established depending on the experimental data. The theoretical calculation results are in good agreement with test data. The research results can provide reference for further research and engineering application of self-stressing steel slag aggregate/concrete@circular steel tube columns.

Analysis and Experimental Study on Shear Bearing Mechanism of Underpinning Beams Based on Truss-Arch Model

To establish a simplified analysis model of the shear bearing capacity of underpinning beams and study the shear bearing mechanism of underpinning beams, two underpinning beams adopting the roughening + planting bar + building glue connection method were tested and analyzed. The experimental and numerical analysis results show that the initial slip bearing capacity and initial slip amount of the underpinning beam are small, indicating that the connection method of roughening + planting bar + building glue is effective and feasible.The failure mode and mechanical performance of the underpinning beams are similar to the bending shear failure of a cast-in-place deep beam, and the crack development rule and failure mode of the specimen are in good agreement with the mechanical characteristics of the truss-arch model. Moreover, the theoretical and numerical results show that by increasing the reinforcement ratio of the stirrups, the ultimate bearing capacity of the underpinning beam can be improved, and the slippage between the new-to-old concrete of the beam can be effectively reduced. Finally, based on the truss-arch model theory and considering the concrete arch effect and softening effect, the shear bearing capacity calculation formula of the underpinning beam is established. The results show that the truss-arch model is applicable to the bearing capacity analysis of underpinning beams and provides a new perspective for the bearing capacity calculation of similar underpinning beams.

Discussion on Parameter Value and Application of Foundation Bearing Capacity Calculation Formula in Code for Design of Building Foundation

Article 5.2 of the Code for Design of Building Foundation gives the calculation formula of foundation bearing capacity. Some parameters in the calculation formula have the same symbols in front and back references, while the meanings represented by the parameters are different, resulting in the possibility of misuse by designers in the actual application process. According to the principle of soil mechanics, this paper discusses the situation that some parameters in the calculation formula of foundation bearing capacity are easily confused, which has certain reference value for correctly understanding the application of the calculation formula of foundation bearing capacity in foundation design.

A Full‐Scale Field Study on Bearing Characteristics of Cast‐in‐Place Piles with Different Hole‐Forming Methods in Loess Area

This paper presents the results from a full‐scale field study on the 3 different types of cast‐in‐place piles: rotary drilling piles (RDPs), manual digging piles (MDPs), and impact drilling piles (IDPs), for a bridge construction project of Wuqi–Dingbian Expressway, in Shaanxi. The results indicate that under the similar conditions, MDP exhibits the largest bearing capacity (11000 kN) in the loess area, followed by RDP (9000 kN) and IDP (8000 kN). And all tested values exceed the estimated value (7797.9 KN), indicating that the calculation formula of bearing capacity recommended by the Chinese standard is safe and conservative. During the load transfer process, the axial force attenuation rate of the pile body increases with pile side resistance. The average attenuation rate of MDP is the largest (24.2%), followed by RDP (19.72%) and IDP (16.69%). The bearing characteristics of these test piles are mainly pile side resistance, but the manual digging method created the least amount of disturbance to the soil around the pile, and due to its hole wall being rough, this enhances the pile‐soil interactions. Hole‐forming methods mainly affect the exertion of pile side resistance compared with pile end resistance. In view of pile side resistance and pile end resistance not taking effect at the same time, degree of exertion of these 2 resistances should be considered when designing cast‐in‐place piles in loess areas, and different partial coefficients should be used.

Experimental study on the mechanical behavior of RPC filled square steel tube columns subjected to eccentric compression

In order to study the mechanical behavior of reactive powder concrete (RPC) filled square steel tubular columns, this paper designs an eccentric compression experiment for 12 specimens of RPC filled square steel tubular column and studies the effects of failure form, load-displacement curve, slenderness ratio, steel ratio and eccentricity ratio of a eccentrically loaded columns on its mechanical behavior. At the same time, it also compares the experiment results with the bearing capacity calculated with relevant specifications and uses Abaqus to carry out numerical simulation of eccentrically loaded columns. The results show that, the failure form of the eccentrically loaded RPC filled square steel tubular column shows local buckling failure. Before the ultimate load is reached, there is no significant change on the surface of the specimen, and the yield stage of the load-displacement curve is not obvious, either. The results of the bearing capacity calculation formula recommended in CECS28-2012 are close to the experiment results and relatively conservative, so it is more applicable to the bearing capacity design of eccentrically loaded RPC filled square steel tubular columns. The results of the numerical simulation analysis are in good agreement with the experimental results, which can provide theoretical support for engineering practice.

STUDY OF SHORT-TERM FLEXURAL BEHAVIOR FOR GLUE-BAMBOO AND LUMBER BEAMS UNDER DIFFERENT PRE-STRESSED STATES

After a new kind of steel-lumber composite member, named as pre-stress glue-bamboo and lumber beam, was proposed by project team, the bending test was conducted on 12 groups of pre-stress glue-bamboo and lumber beams and 4 groups of ordinary glue-bamboo and lumber beams, and from the ways of failure mode, ultimate load, load-deflection curves and load-strain curves, the influence of pre-stressing tendons number and pre-stress value on glue-bamboo and lumber beams were researched. The result showed that: under the same pre-stress value, with the increase of pre-stressing tendons number, the beam ultimate load and stiffness increased. Under the same pre-stressing tendons number, with the increase of pre-stress value, the beam ultimate load increased, and the stiffness of pre-stressed beams was better than ordinary beams, while the change was small. Compared with ordinary beams, under the same section size, the bearing capacity of pre-stress beams was 1.76~5.66 times of ordinary beams. With the same bearing capacity, pre-stress could save bamboo-lumber composites 13.28%~51.98%, and reduce cost 1.95%~39.61%. Finally, the bearing capacity calculation formula for this kind of member was proposed and verified, which provide a reference for practical engineering.

Experimental and theoretical analysis of CFRP reinforced concrete beam anchored by CF anchors

Carbon fiber-reinforced polymer (CFRP) sheets is used to strengthen RC members widely. However, in the actual projects, premature separation of the CFRP sheet from the concrete surface is observed frequently, key issue in CFRP application is the performance of the connection between the CFRP sheet and the peripheral RC members. This paper presented the results of an experimental study to investigate mechanical properties of carbon fiber (CF) anchor dowels, a new CFRP anchoring method, and based on the experimental results, obtained the bearing capacity calculation formula of concrete beam strengthened with CFRP anchoring by carbon fiber anchor dowels .

The Research on the Affect of Collapse State and Bearing Capacity of the Soil Layer Properties Adjacent to the Bearing Plate of the Multi-Extruded-Expanded-Plates Pile

This paper introduces the research status and analysis of the Multi-Extruded-Expanded-Plates pile (the MEEP pile) at home and abroad, by studying when the plate of pile embedded in different characteristics soil layer, the thickness, physical properties of upper and lower soil layer adjacent to the soil with plate cause the influence on soil break and bearing capacity of the soil layer with plate, analyzing the work together with pile and soil in different soil layer, providing a theoretical basis to improve the calculation formula of bearing capacity of single pile, ensuring the rationality and reliability of the design of the MEEP pile.

Experimental Study on Performance of Steel and Composite Plate Combined Column

Four I-section specimens have been produced, and epoxy resin structural adhesive and bolts have been used to combine the cold-formed thin-walled C steel with bamboo-wood composite plate, through which the cooperative work performance of the combined column was detected, and the failure mode and mechanism were explored. The feature of load vs. deflection and load vs. strain was also analyzed. Then stiffness and calculation formula of bearing capacity were proposed. The results show that the unitary mechanical behavior and plastic properties are very good, and the combined column is divided into three stages from loading to failure, including adhesive cracking, local area degumming and failure. And the stiffness accords with double slash model in serviceability

The Mechanical Properties of FRP Fabric Steel-Reinforced Concrete Columns

The mechanical properties of FRP steel-reinforced concrete columns are discussed. We study the constitutive relation of the concrete, based on the model and the experimental dates for the control the size of affecting parameters. When using the used model, the experimental dates can be reanalyzed and corrected for the intensity correct formula of FRP column. The ultimate bearing capacities of FRP constraint rectangular column use superposition principle to calculate the strength calculation. The ultimate bearing capacity of FRP column is divided into two parts: we conclude the big eccentric bearing capacity calculators formula by the columns bend. Through the study of the column, we concluded that the eccentric loading little eccentric calculation formula of bearing capacity. A case though using the example of this formula is similar with experiments results of the data.

Axial Compression Performance Research of RPC Filled Steel Tube Columns Based on the Unified Strength Theory

With consideration of the intermediate principal stress,the calculation formula of bearing capacity of RPC filled steel tube columns under axial compression is deduced based on the twin shear unified strength theory. Combining with the bond-slip theory,new ultimate bearing capacity formula is derived with the highest regard for bond stress. Compared with the theoretical result and the experimental data,good agreement can be found. The results show that unified strength theory and the bond-slip theory are versatile in theoretical analysis of the column. The analysis results can be provided for the optimum design of RPC filled steel tube and the solution has an important practical value for engineering application.

Experimental Study on Local Compression of Concrete-filled Glass Fiber Reinforced Gypsum Wall Panel

The concrete-filled glass fiber reinforced gypsum wall panel is a kind of panel that the inside cavums of the glass fiber hollow gypsum panel is filled with concrete. The experimental results indicate that the concrete-filled glass fiber reinforced gypsum wall panel which has a better performance of the force and can be used to be the bearing wall of a building can form a novel structural system. When the beams supporting the wall panels, the wall panels which under the beams is in local state of compression. It were gained that when the wall panels are in the local compression state , local pressure loads are primarily borne by the concrete core columns and fiber gypsum board will damage in advance through the eighteen experimental wall panel specimens which in local compression. The test results show that the final destruction of the concrete is caused by being crushed and the contribution of the gypsum wall panel to local compression bearing is small. Compressive stress can only spread in the local loading on concrete core columns, cannot be expanded into an adjacent stud. Finally, the local compression bearing capacity calculation formula of the concrete-filled glass fiber reinforced gypsum wall panel is obtained by analysis of the test results.