Circular Steel Pipe Research Articles

Parametric analysis of innovative corrugated profile of soil‐steel composite bridge

AbstractComposite soil‐steel corrugated structures are well recognized and widely used for construction of culverts and pedestrian or animal crossings. Moreover, for the past decade corrugated soil‐steel structures because of their large span are also recognized and chosen for bridges and tunnels engineering. Record holder composite corrugated structure of 32.40 m span encourages new research in the development of innovations. This paper investigates innovative the deepest corrugation cross‐section strengthened with circular hollow section steel pipes influence on plate utilization of large span soil‐steel composite bridge. The numerical 2D model of 17.5 m span structure was developed for investigation. Parametric analysis indicated that introduction of circular pipes will reduce corrugated profile steel thickness because of reduction of buckling length of straight region of corrugation. Moreover, 3D numerical analysis of buckling shapes allowed to conclude that local buckling of the deepest corrugation of 500 × 237 mm could be controlled strengthening the plates with circular steel pipes.

Experimental study on bond performance of recycled coarse aggregates concrete with circular steel tubes after freeze–thaw cycling

AbstractExtrusion tests were conducted on recycled coarse aggregate concrete with circular steel tubes (RCCST, 100% replacement of recycled coarse aggregate) to investigate the impact of freeze–thaw cycles on bond properties. RCCST samples were subjected to 0, 25, 50, 75, 100, 125 and 150 freeze–thaw cycles and their bond properties were then compared with those of natural coarse aggregate concrete with circular steel tubes (NCCST) after 0, 100 and 150 freeze–thaw cycles. The experimental results indicate that freeze–thaw cycling damages the internal structure of RCCST, causing a significant decrease in interfacial bond strength with an increase in the number of freeze–thaw cycles. Freeze–thaw RCCST exhibits lower peak load and higher peak slip compared to NCCST, with increases of 25.2%, 73.2%, and 70.3% after 0, 100, and 150 freeze–thaw cycles, respectively. Regression analysis was used to derive an exponential equation that describes the relationship between longitudinal strain and strain gauge position. Additionally, a segmented fitting method was employed to obtain an expression for the bond slip of the freeze–thaw RCCST with a circular steel pipe.

Automated Counting of Steel Construction Materials: Model, Methodology, and Online Deployment

Construction material management is crucial for promoting intelligent construction methods. At present, the manual inventory of materials is inefficient and expensive. Therefore, an intelligent counting method for steel materials was developed in this study using the object detection algorithm. First, a large-scale image dataset consisting of rebars, circular steel pipes, square steel tubes, and I-beams on construction sites was collected and constructed to promote the development of intelligent counting methods. A vision-based and accurate counting model for steel materials was subsequently established by improving the YOLOv4 detector in terms of its network structure, loss function, and training strategy. The proposed model provides a maximum average precision of 91.41% and a mean absolute error of 4.07 in counting square steel tubes. Finally, a mobile application and a WeChat mini-program were developed using the proposed model to allow users to accurately count materials in real time by taking photos and uploading them. Since being released, this application has attracted more than 28,000 registered users.

Investigation on bearing resistance of thin-walled circular steel tube subjected to eccentric loading

In the engineering structures using circular steel tube (CST), the eccentric loading of CST members often occurs due to installation error and structural form. Existing research mainly focuses on the bearing resistance of circular steel pipes under the condition of eccentricity at one end. In practical application, both ends of CST members also may be eccentric. And with the increase in eccentricity, material yielding may occur prior to flexural buckling. So far, it’s lack of reports about the mechanical behavior of CST members subjected to eccentric loading at both ends and the boundary between material yielding and flexural buckling. This paper presents experimental, numerical and theoretical studies on bearing resistance of thin-walled circular steel tube with slenderness ratio of 30, 40 and 50, subjected to eccentric loading at one end and both ends, respectively. The study reveals a significant discrepancy in the prediction of bearing resistance for circular tubes subjected to eccentric loading at both ends according to existing design codes. Considering the synthesis of bending moment and deflection caused by eccentric loading at both ends, the calculation method of the bearing resistance based on flexural buckling of CST is established, which enhances the prediction accuracy of test verification. In addition, a theoretical boundary between the two failure modes appearing in CST members under eccentric loading at one and both end(s) - flexural buckling and reaching the material yielding strength - was established as dominated by the slenderness ratio and loading eccentricity.

Analysis on the Influence of Geometric Parameters of a Circular Steel Pipe with Flange Plates on Surface Settlement

Analysis on the Influence of Geometric Parameters of a Circular Steel Pipe with Flange Plates on Surface Settlement

Automatic Verticality Monitoring and Securing System for Large Circular Steel Pipes

Securing the verticality of foundations is a crucial factor for ensuring safety in offshore construction. The repeated intrusion-pulling method is generally used to ensure verticality in suction bucket foundation construction processes. However, it relies heavily on the experience and skills of field workers and is relatively time-consuming. To address this problem, we propose an automatic verticality securing system for large circular steel pipes based on a verticality monitoring system. This system adjusts cables at locations where verticality correction is required without changing the existing suction pile–penetration–construction process. It includes a monitoring component that provides real-time data on pipe alignment and an automatic lifting cable control system that maintains perpendicularity using data acquired from the monitoring system. The monitoring system comprises a sensor, an embedded controller, and a display program that displays the vertical information of circular steel pipes. The automatic lifting cable control system includes a controller with an algorithm for adjusting the length of the actuator. We showed that the system operates satisfactorily and secures the verticality of less than 0.2° in the suction bucket-based model experiment. Furthermore, the testbed experimental results show that our monitoring system can efficiently measure verticality information in real time.

Test on Compressive Performance of Hollow Concrete-Filled Sandwich Circular Steel Tubes Connected by Thread

The connection method of lengthening the steel tube of hollow concrete-filled sandwich circular steel tubes and threaded connections is proposed. The length, depth and position are the basic parameters. Twelve hollow concrete sandwich circular steel pipes with threaded connections were designed and subjected to axial compression tests. The axial compressive loading–longitudinal compressive displacement curves, axial compressive loading strain of steel tube curves and failure mode of the specimens are analyzed, and the effects of different parameters on the axial compressive-bearing capacity and stiffness of the specimens are studied. The results showed that within the range of parameters studied, the axial compression load–longitudinal compression displacement curves of the specimens were the linear elastic stage and the elastic–plastic stage, which can be divided into a yield-strengthening stage and a decreasing stage. The bearing capacity and strength of the lined threaded connection specimen are not inferior to those of the ordinary specimen or the welded specimen. The bearing capacity and strength of the specimen increase with the increase of the thread length. The bearing capacity and strength of the specimens connected with inner liner screws at the ends are higher than those connected with inner liner bolts at the middle.

Dispersion characteristics of surface wave in SCCS: theoretical analysis, numerical simulation and MASW-based NDT

To fully validate the feasibility of multichannel analysis of surface waves (MASW)-based interfacial debonding detection for steel–concrete composite structures (SCCS), dispersion characteristics of surface waves in SCCS are systematically investigated using theoretical analysis and elaborate 3D numerical simulations. First, the influences of material strength and thickness of concrete core, steel plate thickness on the dispersion figures are analyzed based on the theoretical dispersion characteristic of Rayleigh wave. Scientific layering strategy, including single steel plate, double-layer, and three-layer medium assumptions, is investigated using the theoretical dispersion analysis of Lamb wave. Besides, the dispersion characteristics of surface wave in circular steel pipes are calculated to determine the appropriate theoretical dispersion curves for MASW measurement. Finally, the stress wave propagation processes in SCCSs with various internal structures, including stiffeners, studs, and diaphragms, as well as the debonding width, are simulated using 3D numerical simulation to validate the research finding of theoretical analysis and detectability of MASW-based non-destructive testing on interfacial debonding defects in rectangular and circular concrete-filled steel tubulars. Finally, the dispersion characteristics corresponding to displacement, velocity, and acceleration of surface waves are comparatively discussed. The research findings of this study are the cornerstone of experimental study and essential theoretical support for identifying interfacial debonding and bond-slip damage of SCCS components utilizing MASW method.

Nonlinear analysis of axial-compressed corroded circular steel pipes reinforced by FRP-casing grouting

In this paper, ABAQUS software is used to carry out finite element simulation on the axial compression performance of corroded round steel pipe members reinforced by FRP casing grouting. Moreover, its working mechanism and failure mode are analyzed. A typical load-displacement curve of the component is obtained. Furthermore, the effect of FRP pipe thickness, grouting thickness, corrosion rate, concrete strength, and slenderness ratio on the mechanical performance of the component is explored. The research results indicate that the component load-displacement curve can be characterized by bilinear and trilinear models. The former corresponds to the overall buckling failure mode, while the latter corresponds to the strength failure mode for the bare ends of a round steel tube. After reinforcement, the component bearing capacity increases up to 166.83%. Moreover, the increase is positively correlated with FRP pipe thickness, grouting thickness, and corrosion rate. The component bearing capacity first decreases and then increases when modifying the slenderness ratio, while concrete strength has a minor effect on it. Moreover, the bending stiffness ratio equation and the stability bearing capacity correction equation of the axial compression reinforced components are proposed. The aforementioned provides reference suggestions for practical engineering applications of corroded steel structures reinforced by FRP casing grouting.

Experimental Study on Compressive Performance of CHS T-Joints Filled with High-Water Rapid-Setting Materials

In order to study the compressive performance of the CHS joints filled with high-water rapid-setting materials, the comparative test of the branch axial compression of three T-joint specimens of circular hollow steel (CHS) pipes, chord filled with concrete and chord filled with high-water rapid-setting materials were carried out. Differences in the failure mode, stress-strain distribution, ultimate bearing capacity and initial stiffness of the three joints were comprehensively compared. The test results show that the filling of the chord with different materials leads to different failure modes. Filling concrete can significantly improve the bearing capacity of the joint, but it will reduce the ductility of the joint; the failure mode of the filled with high-water rapid-setting materials is similar to that of the CHS T-joint. The joint show good ductility during the stress process, and at the same time, the ultimate bearing capacity is appropriately increased compared with the CHS T-joint.

Analysis of the influence of geometrical parameters of circular steel pipe with flange plate on the jacking force

Jacking force is one of the important safety indicators during pipe jacking construction. Existing models for calculating jacking force are widely used in the calculation of jacking force for pipe with regular cross-sections. In this paper, considering pipe-soil interaction, the cross-sectional characteristics and the distribution characteristics between pipe and soil, the calculation equations for the jacking force of circular steel pipe with flange plate were proposed based on the pressure arch theory. The proposed equations were applied to calculate the jacking force for the Olympic Sports Center Subway Station of Line 9 in Shenyang, China, and the results were compared with the field monitoring data to predict the accurate jacking force. Based on the proposed equations, the influences of the flange plate position and steel pipe diameter on earth pressure around the pipe were analyzed. The functional relationship between the earth pressure and the position of flange plate or the pipe diameter was obtained, which provides design basis and theoretical guidance for engineering practice.

Seismic performance of prefabricated middle frame composed of special-shaped columns with built-in lattice concrete-filled circular steel pipes

Prefabricated buildings are green and environment-friendly, with high construction efficiency. Concrete-filled steel pipe structures have high bearing capacity and strong deformation ability. Special-shaped column frame structures of prefabricated concrete-filled circular steel pipe with built-in lattice can give full play to the advantages of prefabricated buildings and concrete-filled steel pipe structures, with the advantage of high space utilization rate of special-shaped column structures. In order to study Seismic performance of frame in special-shaped columns of prefabricated concrete-filled circular steel pipe with built-in lattice, a full-scale middle frame model specimen with two floors and two spans was designed, and the failure mechanism of the specimen was obtained by low-cycle loading test. The hysteretic performance, deformation capacity, energy dissipation capacity and stiffness degradation of the specimen were analyzed. The results showed that the failure mechanism of the prefabricated concrete-filled steel tubular special-shaped column is a typical beam hinge mechanism, which meets the design requirements of “strong column and weak beam”. The special-shaped columns frame of built-in concrete-filled circular steel pipe has full hysteretic curve, good ductility and energy dissipation capacity, and stable stiffness degradation. When the specimen is damaged, the inter-story drift angle reaches 1/23, which is much higher than the limit requirement of elastic–plastic inter-story drift angle of 1/50 under strong earthquake. The existence of built-in concrete-filled steel pipe changes the bearing mechanism of the structure. After the external concrete falls off, the internal force of the structure redistributes, forming a stress system of built-in concrete-filled steel pipe truss. The post-cast joint between overlapping precast column and superposed beam and grouting connection joint between precast column and column sleeve are not damaged, and the fabricated joints are safe and reliable.

Suction Penetration Review of Circular Steel Pipes by Field Test

Suction Penetration Review of Circular Steel Pipes by Field Test

Verticality 3D Monitoring System for the Large Circular Steel Pipe

Verticality 3D Monitoring System for the Large Circular Steel Pipe

Field Study on Wireless Remote Sensing for Stability Monitoring of Large Circular Steel Pipe for Marine Bridge Foundation

Field Study on Wireless Remote Sensing for Stability Monitoring of Large Circular Steel Pipe for Marine Bridge Foundation

Finite Element Analysis of Influencing Factors of Micro Round Steel Pipe Pile Based on Pure Bending Orthogonal Test

Based on the pure bending orthogonal test of different diameter grouting micro circular steel pipe, the influence of the parameters such as steel ratio, steel yield strength, the type and strength of filling material on the bending performance of the grouting steel pipe pile was simulated by the finite element software. The results show that the error between the ultimate bearing capacity of the cast-in-place steel pipe pile simulated by the finite element method and the test data is between 6.4% and 13.6%, which is in good agreement and can be used for simulation calculation; under the pure bending action, the steel content of the cast-in-place steel pipe component has a great influence on its bearing capacity; the yield strength of the steel pipe has a significant effect on improving the bending bearing capacity of the micro steel pipe pile; the filling core material of the steel pipe The influence of strength on flexural capacity is less, so the core filling material with low compressive strength can be used to reduce the investment.

Experimental and finite element study on the single-layer reticulated composite joints

In this article, a new type of reticulated joint, named the steel–concrete composite reticulated shell joint, is proposed. The proposed reticulated shell joint consists of an inner circular steel pipe, an outer circular steel pipe, a steel cover plate, and internal concrete. Five test specimens were tested under axial compression. The variable study included the wall thickness of the inner and outer circular steel pipes and the radius of the inner circular steel pipe. The test specimens exhibited a high bearing capacity and good plastic deformation ability under axial compression. The test results show that the wall thickness of the outer circular steel pipe and the radius of the inner circular steel pipe have a great influence on the bearing capacity of the steel–concrete composite reticulated shell joint, while the wall thickness of the inner circular steel pipe has little influence on the bearing capacity of the steel–concrete composite reticulated shell joint. Based on the test of the steel–concrete composite reticulated shell joints under axial load, the three-dimensional nonlinear finite element model was used to analyze the mechanical properties of the steel–concrete composite reticulated shell joints under axial compression. The results of the finite element analysis showed good agreement with the experimental results. The formula for calculating the bearing capacity of the joint is derived. By comparing with the experimental results, the calculated results are basically consistent with the experimental results.

Analysis of circular steel tubular columns under the coupling of fire and impact

Aiming at the coupling of a pair of sliding circular steel tubular columns with one end fixed by fire and impact, this paper analyzes the model by finite element software ABAQUS. The impact load is applied to the mid-span of the test piece. Through the analysis of the displacement of the mid-section of the test piece, the following three points are clarified: 1) The circular steel pipe column absorbs energy through integral plastic deformation and local plastic deformation; 2) The displacement of the end of the circular steel tubular column and the displacement and displacement of the upper and lower surfaces of the span depend on the axial compression ratio, the impact velocity and the temperature; 3) Under the coupling of fire and impact, the safe area of the column member depends on the temperature. And axial compression ratio; the greater the temperature and axial compression ratio, the smaller the safety zone. In order to study the concrete-filled steel tube under the coupling of fire and impact.

An experimental study on particle evolution in the exhaust gas of a direct injection SI engine

The measurement results for exhaust nucleation mode particles in internal combustion engines are not easy to repeat and very sensitive to the measurement processes in laboratory experiments. In this study, particle numbers and size distributions were measured at different sampling points along an exhaust system of a single-cylinder gasoline direct injection engine, which consists of an exhaust plenum chamber and circular steel pipes. Different injection timings and two fuels including gasoline and ethanol were tested. Particle evolution in the exhaust gas was analyzed. One sampling point upstream and five sampling points downstream the exhaust plenum chamber were measured with the exhaust temperature dropping from 630 °C to 170 °C. For gasoline, when the sampling point shifts from the upstream to the downstream of the exhaust plenum chamber, the particle number concentrations of accumulation mode decrease by 7%–10%, and the particle number concentrations of nucleation mode decrease by 50%–98%. A trade-off between the particle number concentrations of nucleation mode and accumulation mode with varied injection timings is observed downstream of the exhaust plenum chamber, indicating that coagulation between solid core particles and accumulation mode particles occurs in the exhaust plenum chamber. It is concluded that intensive particle coagulation occurs inside the exhaust plenum chamber, leading to reduction of solid core particle number concentration and the resultant different measurement results of nucleation mode particles in the downstream exhaust gas. For ethanol, the particle number concentration reduction is less than 20% regardless injection timings due to the ultra-low accumulation mode particles. The particle number concentration reductions along the five sampling points downstream of the exhaust plenum chamber are negligible.

Small-Scaled Laboratory Experiments for Dynamic Stability Monitoring of Large Circular Steel Pipe Cofferdam of Marine Bridge Foundation

Small-Scaled Laboratory Experiments for Dynamic Stability Monitoring of Large Circular Steel Pipe Cofferdam of Marine Bridge Foundation