Steel Pipe Column Research Articles

Experimental investigation on mechanical properties of fiber recycled concrete filled-square steel tube columns under pure flexural based on acoustic emission technique

Currently, global countries are actively focusing on carbon emission reduction. Utilizing recycled aggregate concrete (RAC) is expected to realize global carbon neutrality objectives. However, due to its inherent mechanical limitations, its application in structural contexts is restricted. This study aimed to enhance the mechanical attributes of RAC and expand its utility beyond low-strength applications. By employing recycled aggregates, steel fibers, and ordinary Portland cement, a novel eco-friendly composite filler was developed for steel- tube filling. A comprehensive study on 16 concrete mix ratios and 23 steel-tube recycled concrete columns was conducted. The parameters included the recycled aggregate volume, steel fiber content, and steel pipe thickness. The results revealed that reasonable mix design enabled RAC to exhibit flexural performance similar to that of conventional steel-tube concrete. Moreover, while increasing the recycled aggregate content deteriorated the overall mechanical properties, incorporating steel fibers extended the elastic stage and enhanced the flexural characteristics. Optimal results were achieved with 1.2 % steel fiber addition and 75 % recycled aggregate. The comparison between the derived equation and the experimental data demonstrated a high level of agreement, confirming the accuracy of the equation. Furthermore, acoustic emission technology was employed in this experiment to monitor the failure progression of steel tube recycled concrete columns subjected to a pure bending load. The findings revealed a triphasic failure process: elastic, elastic-plastic, and strengthening stages. The analysis demonstrated a consistent correlation between acoustic emission parameters and waveform characteristics with the failure process of the specimen. Empirical evidence demonstrated the efficacy of acoustic emission technology in effectively monitoring the damage severity and failure chronology in recycled concrete steel pipe columns during bending.

Application of steel frame viaduct for mountainous roads in Vietnam: Case studies in Quang Ngai Province and Lam Dong Province

Vietnam’s mountainous highways are increasingly affected by landslides each year, with climate change being a major cause. The government has allocated significant funds to repair, rehabilitate, and maintain these highways, but conventional methods like excavation and embankment are not always effective for roads that pass through unstable, large-angle slopes that have a high risk of landslides. This results in additional rehabilitation costs following natural disasters. To address this issue, JFE Civil Engineering & Construction Corporation has developed a new solution for constructing mountainous highways in Vietnam - a viaduct that functions as a space steel frame supported by steel pipe columns and beams. Prefabricated in a factory and transported to the construction site, the steel beams are then assembled, and steel piles are driven deep into the ground for a rigid pile-to-ground connection. These proposed structures offer sustainable and cost-effective solutions for mountainous highways with minimal impact on the surrounding environment. Two case studies in Quang Ngai Province and Lam Dong Province are presented as preliminary designs to demonstrate the feasibility of this solution.

Size optimization and co-operative support mechanism of coal pillar in residual resources recovery working face

In this paper, a numerical calculation model of the mining face was established to analyze the rational size of coal pillars in the goaf on both sides by using FLAC3D based on the mining geological conditions in the pilot area. Furthermore, the feasibility of co-ordinated reinforcement with steel pipe column was explored, which can be applied to the recycling of residual coal resources like protecting coal pillars and of great value to increase the recovery rate in gobs as well.

Analysis and Field Measurement on the Internal Force Variation Laws of Steel Pipe Columns in Subway Stations

Steel pipe columns are an important component in subway station construction and with stand stress state and internal force during the construction process. Based on the engineering background of Beijing subway, this paper introduces the geological conditions, station structure types, and internal force monitoring of steel pipe columns of 10 subway stations constructed by the PBA method. The field monitoring indicates that the greatest change in the internal force of the steel pipe column occurs during stage 1 (beam, primary support, and secondary lining buckle arch construction stage), no matter pile foundation station or strip foundation station, which accounts for about 60% to 65% of the total axial force. When the left and right spans are not synchronously arched or excavated, the steel pipe column is subjected to uneven forces and bears a large bending moment is produced. When the depth of overburden is between 7 m and 15 m, the internal force of the steel pipe changes positively correlated with the overburden depth. During the construction process, the internal force of the steel pipe varies widely in the silty sand stratum. Also, the steel pipe columns in stations affected by groundwater bears about twice of the axial force compared with other stations are not affected by groundwater. In addition, the construction period is also a factor that affects changes in internal forces. This research is conducive to update the database of the world subway projects and can serve as a practical reference for similar geological condition.

A numerical analysis on bending capacity of steel pipe columns using a mechanical joint with concrete-filled steel tube

Structural steel pipes have been applied commonly in the bridge construction for foundations or piers with many advantages such as large bending capacity, high shear resistance, and rapid construction. However, site welded joints may face critical technical matters which need to be considered for steel pipe piers during construction stage. Current solutions for pipe joints require the use of high-strength materials with machining technology to ensure accuracy, quality, and increase construction costs with substantial number of joints. Therefore, these solutions, when applied in Vietnam, will also face limitations due to the contractor’s qualification and erection technology at construction site. This study proposes a type of joint for steel pipe piers of viaducts in a mountainous region to eliminate the welding work of the steel pipe at the construction site and to provide high bearing capacity, simple construction, and cost effectiveness. Finite element analyses are conducted to investigate and verify the bending capacity of steel pipes with the proposed joint. Nonlinear material and nonlinear geometry are considered to simulate behaviors of composite action, yielding, and buckling in the structures. Finally, comparative studies of bending capacity of the steel pipe with and without joint are performed. Stress distributions and deformations of the structural components in the joint region are also observed and discussed.

Proposed New Analytical Method of Tower Load in Large-Span Arch Bridge Cable Lifting Construction

The cable lifting construction method is the most widely used construction method for large-span arch bridges. The correct calculation and analysis of cable lifting construction is essential to ensure the safety and linearity in the construction of arch bridges. The existing research mainly focuses on the construction scheme and finite element analysis of cable lifting for large-span arch bridges. There is relatively little research on calculation theory, and there is no analytical method for cable lifting construction of arch bridges. To calculate and analyze cable lifting construction more quickly and accurately, based on the deformation coordination principle and suspension cable theory, a practical calculation method is proposed to calculate the load of the tower acting by a cable system in the cable lifting construction of arch bridges. A large-span arch bridge under construction was used as a case study, and the correctness of the calculation method was verified by measuring the displacements of the tower top. A brief description of the structure, verification method, and verification process is presented. The displacement results are calculated by the numerical calculation software SAP2000, the actual measured displacement data are discussed and comparatively analyzed, and the correctness and calculation accuracy of the proposed calculation method are also evaluated. The results show that the calculation method has sufficient accuracy. The tower load calculation is mainly undertaken to prepare for the analysis of the tower mechanical properties; therefore, the calculation method is applied to towers of the case engineering, and the stability, load carrying capacity, and deformation of the tower are analyzed to verify whether its mechanical properties meet the engineering requirements. The results show that steel pipe columns of the buckle tower are prone to twisting instability. The normal stress of the tower’s part of the pressurized rod or pressurized bending rod is larger. Wind cable load calculation models and tower design-related recommendations are presented in this tower analysis. The tower load calculation method and tower mechanics analysis method in this study can provide guidance for the calculation and analysis of the cable lifting construction of large-span arch bridges.

Seismic Performance of Composite Shear Walls Filled with Demolished Concrete Lumps and Self-Compacting Concrete after Fire

In order to provide a good solution for the treatment and utilization of construction waste, especially waste concrete and to promote the development of green construction to some extent, in this paper, a new composite shear wall filled with demolished concrete lumps (DCLs) and self-compacting concrete (SCC) was proposed, and its seismic performance after fire was investigated. Based on quasi-static tests of four composite shear walls filled with DCLs and SCC, three after a standard fire and one contrastive specimen without fire, the effects of fire exposure time, fire-retardant coating on the edge constraint steel pipe column, and the width-thickness ratio on seismic performance of composite shear walls after fire were studied. The failure patterns, bearing capacity, hysteretic loops, ductility, skeleton curves, rigidity degradation curves, and energy dissipation of shear walls were analyzed and compared. Test results indicate that the bearing capacity of the shear wall after 60 min of standard fire is slightly lower than the contrastive specimen without fire, but specimens still have good seismic performance. The interlayer displacement angle of the shear wall after a fire still meets the requirement of regulations. The fire-retardant coating on the edge of concealed steel pipe column has a limited effect on the seismic performance of specimens after a fire. The horizontal bearing capacity and energy dissipation capacity of shear walls after a fire can obviously be improved by properly increasing the width-thickness ratio.

Xiong'an Railway Station: A Supersized Railway Station in a High Seismic Intensity Zone

Xiong'an Railway Station is the first super-large elevated railway station located in a high seismic intensity zone. A reinforced concrete frame structural system is adopted for the rail-bearing floor and the lower floors, while a steel structural system is adopted for the large-span roof. H-shaped steel frame beams are adopted for the elevated waiting hall, while double flange H-shaped steel beams are adopted in areas subject to great forces. Plane trusses are arranged bidirectionally between the frame beams to facilitate the laying and maintenance of equipment pipelines. The main span of the elevated waiting hall is 78 m, and variable-height box beams are adopted. The platform canopies are supported by specially shaped steel pipe columns, and the roof frame beams are connected to the tops of columns through spherical bearings. Structural innovations have been carried out in terms of semi-embedded column bases, stepped wall thickness steel pipe columns with special section shapes, large-span stiffened thin-walled box beams, and bidirectional large displacement bearings.

Optimum Design of Excavation Deepening for Deep Foundation Pits in Complex Sites

Many historical buildings in the old urban area of Zhongshan Road in Guangzhou have high commercial value and requirements for large underground space. However, their safe development is restricted by many factors, such as limited surrounding space, dense underground pipe networks, poor engineering properties of shallow soft soil, and excessive amounts of groundwater. Hence, this work proposes an optimized approach in which the current supporting structure of foundation pits is used for basement expansion in complex environments.A case study of a basement expansion in Honghui Plaza II, Guangzhou, P.R. China, was exemplified in this work. The original foundation pit needed to be deepened to expand the current three-story basement into a four-story one. Although the original diaphragm wall was excavated nearly 10 years ago, it was proved to be suitable for further usage after quality inspection. Thus, together with the partial roof of the basement and steel pipe columns, the diaphragm wall was utilized as a part of the support system. Several measures were taken to avoid deformation risk resulting from short embedded sections. They included structure optimization of the current support system and effective control of the earthwork excavation process. The deformation of the supporting structure and adjacent subway tunnel was simulated using the finite element method during excavation. Results showed that the simulation was basically consistent with the field monitoring value. The excavation deepening of the foundation pit in this case study was proved in practice to have little impact on the surrounding environment. Therefore, the results of this work can serve as a reference for similar urban renewal projects in the future.

A study of the mechanical behavior of rectangular steel tubular column strengthened using intermittent welding angle steel

From the perspective of the development of steel structures in China, the existing steel structure had experienced decades of service. However, due to the change of its functionality, and the erosion caused due to the surrounding environment, reinforcement of steel has become necessary. Thus, the research on reinforcement theory and methods of the existing steel structures has become an important measure in the “reinforcement period”. Steel angle welding on the surface of steel columns is a common method used in practical engineering. However, the traditional continuous welding angle steel reinforcement of rectangular steel pipe columns leads to a large amount of welding work on the construction site, thus prolonging the construction time and increase the project cost. Moreover, the quality of welding also cannot be guaranteed. Therefore, in order to reduce the cost of field welding and reinforcement of the construction project, intermittent welding is proposed in this work. In this paper, the finite element analysis of rectangular steel tube column models that were strengthened using different intermittent welded angle steel under axial and eccentric compression is discussed out and the results are compared with the experimental results for validation. Further, a large number of numerical models with different parameters are analyzed. From the analysis, the ultimate bearing capacity and the load transfer mechanism of the rectangular steel tube columns that were strengthened using intermittent angle steel under eccentric and axial compression are studied, and the optimal weld spacing and weld length are obtained. The results provide a theoretical base for future practical engineering applications.

Seismic performance of curved haunched connections in modularized prefabricated steel structures

In this study, curved haunched connections were developed for modularized prefabricated steel structures, where prefabricated steel pipe columns with curved haunches and H-beams are assembled on-site with connectors and bolts. The seismic performance of the developed connections was investigated, based on a cyclic testing and finite element analysis of two full-scale specimens. Critical seismic performance measures associated with the joints, such as the failure pattern, hysteresis property, stiffness degradation, ductility, and initial rotational stiffness, were analyzed; furthermore, the effectiveness of the different curved haunches in enhancing the seismic performance of the joints was discussed. A comparative analysis based on experimental and numerical tests revealed that the curved haunches could increase the flexural resistance of the steel pipe columns, change the internal stress distribution of the steel H-beams, and enhance the rotational stiffness of the joint. Owing to the existence of the curved haunches, the beam flanges around the haunch ends fail prior to the damage of the H-beam ends. Connections with shorter haunches are more prone to yielding, owing to the shorter legs of the haunches causing greater stress concentrations in the beam flanges around the haunch ends. In addition, the ductility of the connections crucially hinges on the beam flanges around the haunch ends, where proper strengthening is required to diminish the stress concentrations and section weakening caused by the bolt holes. Both connections can be classified as rigid, and the initial rotational stiffness is related to the length of the curved haunch. This study also presents a theoretical calculation method for the elastic panel zone rotational stiffness.

Experimental study on bearing capacity of single steel pipe column for fully united framework

It is analyzed and tested the substitution of triangular section columns for single steel outgoing line columns in the 500kV fully united framework based on the design, test and analysis with 18 specimens of single steel pipe. The theoretical calculation method of bearing capacity is put forward by analyzing the design theory. Through the experimental analysis and research, the computational model with bottom fixed, middle hinged and top hinged is obtained, which is consistent with theoretical values, thus providing valuable reference conclusions for the revision of the specification. It provides meaningful theoretical and experimental data for the analysis and calculation of substitution of single steel pipe outgoing line column for the original triangular section outgoing line column for the 500kV fully united framework.

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.

Study on force of steel bracket for construction of large span and wide steel box girder

Dongping waterway bridge is a steel concrete composite single-tower cable stayed bridge with spans of 35+260+50+64+66 m. The bridge M21-M31 beam section is constructed by steel pipe bracket. The Steel pipe column is designed for transverse bridge to 2 groups of 4 rows, each 2 rows connected into a group, and the steel pipe column is connected through the profile steel connection system. The top of steel pipe column is equipped with profiled steel beam, the profiled steel distribution beam is equipped with bailey beam and I-beam, and the longitudinal moving push-up slideway of the steel box beam is installed on the I-beam. In order to check the safety of steel pipe bracket in construction stage, the finite element model of steel pipe bracket and the field measured steel pipe stress are established by MIDAS software. The results show that the force and alignment change of the steel bracket construction used in this bridge is reasonable. In addition, through the finite element optimization of the existing bracket, it is proved that the optimized steel bracket structure can save 20% steel consumption under the premise of ensuring safety, which provides a reference for similar projects.

Research on the Application of Fabricated Steel Structures to the 220kV Indoor Substations

The significant development of fabricated steel structure is helpful to solve the issue of excessive productivity in steel industry and promote the greenization, informatization and industrialization in construction industry. This paper takes a 220kV indoor substation for example to compare the stress ratio, displacement, types of joints and steel quantity of the steel pipe column frame with those of the mixed one. The result demonstrates that the employment of steel pipe columns for indoor substation structures can generate certain economic and social benefits.

A Vision-Based Algorithm for Deformation of Steel Pipe Column Detection

It has great significance for assessing the safety of engineering structures or the bridge by detecting Deformation of steel pipe column. The manual contact measurement is one of the traditional methods to detect the deformation of the steel pipe column. However, in the actual operation environment, the manual contact measurement is difficult and there are some hidden safety problems in the measurement process, thus it is particularly important to study a non-contact measurement method of the steel pipe column. Image processing is one of the common methods of non-contact measurement. In this paper, with the same steel pipe deformation image, respectively, using different edge detection algorithm, comparative analysis of the result, it come to a conclusion that the most suitable algorithm is Canny algorithm, and it is a classic algorithm of edge detection which has been applied in image processing. However, the traditional Canny algorithm has some defects, such as difficulty in threshold setting, low efficiency. Based on traditional Canny algorithm to improve it, this paper proposes an improved custom threshold Canny algorithm. The results show that the method proposed in this paper, the method of which is more than the traditional detection method to save at least 0.8s. Basically meet the requirements of real-time detection of stable and reliable, fast, high accuracy, and has a certain practicality.

Attenuation of ambient vibrations induced in urban buildings

A numerical study of a control system to attenuate the vibrations induced by traffic in buildings is presented herein. Three-dimensional finite-element method numerical models of the structures were built, including the influence of masonry walls and soil–foundation interaction, in order to estimate their dynamic characteristics, as well as time history responses to vibrations induced by the traffic of heavy vehicles. The models were calibrated through correlation with the experimental data obtained with the uncontrolled structure. The description, results and analysis of the extensive experimental measurements constitute a fundamental part of the work and are summarised herein. The responses obtained with the models were used to present alternative solutions to the problem. One of these solutions is composed of prestressed slender steel pipe columns with rubber pads at their tops to be installed in between the floor slabs of the building. The good effectiveness of this solution is demonstrated through numerical simulations.

강재기둥과 PHC 파일을 연결하는 반구형 접합부(HAT Joint)의 유한요소 해석 PART I : 원형강관기둥

To overcome disadvantages of usual spread foundation in large space structure, some prototypes of a joint of the PHC pile to steel pipe column that directly connects a column to a PHC pile are analytically studied. With the consideration of strength requirement and stress concentration of joint of the PHC pile to column, we suggest the most appropriate one.

Shear Strength of Connections between Concrete Filled Steel Tubes and Beams

Departure from the stress state of the steel pipe concrete dye column node, axial force, steel pipe column end moments and stained end vertical shear strength Shear strength concrete filled steel tube the formula, using the finite element analysis software ANSYS to establish a three-dimensional nonlinear finite element model, comparing the results calculated by the finite element calculations and formulas seen, the model is applied to the concrete filled steel tube - steel beam finite element nodes analysis.

Excel Programming and Application for Concrete Filled Steel Tubular Structures

We used to use the method from for the calculation on bearing capacity of steel pipe columns for a review. This paper improves this method, and uses excel in formula programming to calculate the internal forces from SAP2000. It effectively improves the efficiency of the structure designing.