scholarly journals Evaluation of Ultimate Bearing Capacity of Pre-Stressed High-Strength Concrete Pipe Pile Embedded in Saturated Sandy Soil Based on In-Situ Test

2020 ◽  
Vol 10 (18) ◽  
pp. 6269 ◽  
Author(s):  
Yingjie Wei ◽  
Duli Wang ◽  
Jiawang Li ◽  
Yuxin Jie ◽  
Zundong Ke ◽  
...  

Estimation of ultimate bearing capacity (UBC) of pre-stressed high-strength concrete (PHC) pipe pile is critical for optimizing pile design and construction. In this study, a standard penetration test (SPT), static cone penetration test (CPT) and static load test (SLT) were carried out to assess, determine and compare the UBC of the PHC pipe pile embedded in saturated sandy layers at different depths. The UBC was calculated with three methods including the JGJ94-2008 method, Meyerhof method and Schmertmann method based on in-situ blow count (N) of SPT (SPT-N) which was higher than the values recommended in survey report regardless of pile length. The average UBC values calculated with cone-tip resistance and sleeve friction from CPTs was also higher than the value recommended in the survey report. Moreover, the actual UBC values directly obtained by load-displacement curves from SLTs were in line with the calculated values based on in-situ SPTs and CPTs, but approximately twice as high as the values recommended in the survey report regardless of pile length. For the SPT method, the application of bentonite mud in saturated sand layers is critical for the assessment of pile capacity in the survey phase, CPTs can provide reliable results regardless of soil characteristics and groundwater if the soil layer can be penetrated, and SLTs are necessary to accurately determine the UBC in complex stratum.

2021 ◽  
Vol 11 (21) ◽  
pp. 10468
Author(s):  
Huanjun Jiang ◽  
Ahmed Salih Mohammed ◽  
Reza Andasht Kazeroon ◽  
Payam Sarir

The ultimate strength of composite columns is a significant factor for engineers and, therefore, finding a trustworthy and quick method to predict it with a good accuracy is very important. In the previous studies, the gene expression programming (GEP), as a new methodology, was trained and tested for a number of concrete-filled steel tube (CFST) samples and a GEP-based equation was proposed to estimate the ultimate bearing capacity of the CFST columns. In this study, however, the equation is considered to be validated for its results, and to ensure it is clearly capable of predicting the ultimate bearing capacity of the columns with high-strength concrete. Therefore, 32 samples with high-strength concrete were considered and they were modelled using the finite element method (FEM). The ultimate bearing capacity was obtained by FEM, and was compared with the results achieved from the GEP equation, and both were compared to the respective experimental results. It was evident from the results that the majority of values obtained from GEP were closer to the real experimental data than those obtained from FEM. This demonstrates the accuracy of the predictive equation obtained from GEP for these types of CFST column.


2020 ◽  
Vol 980 ◽  
pp. 282-290
Author(s):  
Shi Meng Wang ◽  
Xin Sheng Yin

Prestressed concrete pipe pile with high bearing capacity, the advantages of convenient construction, low cost and widely used in practical engineering, because of the prestressed high strength concrete in use process is in complex stress state, both are under a lot of vertical load, and horizontal seismic action needs to be considered at the same time, it is necessary under the condition of considering the vertical load bearing capacity of prestressed high strength concrete level and considering the loading level, the horizontal bearing capacity. Scholars at home and abroad based on the simple hypothesis, puts forward the calculation method of a lot of interaction with soil, in the future will be adopted in calculation, using ABAQUS finite element analysis, this paper established the three-dimensional finite element model of prestressed concrete pipe pile, respectively under different vertical pressure (P = 4000 kn, P = 4800 kn, P = 6000 kn) one-way load and calculated the horizontal bearing capacity, and under repeated load, respectively to study the size of the different vertical pressure and different reinforcement stirrup ratio on its bearing capacity and seismic performance. The results show that the stiffness of pipe pile decreases significantly with the increase of vertical pressure under different vertical loads. With the increase of vertical load, the ductility and energy dissipation capacity of the components decrease gradually. The horizontal bearing capacity of prestressed high strength concrete pipe decreases with the increase of vertical pressure. However, its amplitude decreases with the increase of vertical pressure value.


2014 ◽  
Vol 578-579 ◽  
pp. 340-345
Author(s):  
Guo Chang Li ◽  
Bo Wen Zhu ◽  
Yu Liu

In this paper, using ABAQUS, 16 high-strength concrete filled high-strength square steel tube middle-long columns’ axial compression process were simulated. The load-deflection relationships were obtained and the new combination in improving the bearing capacity and plastic deformation has a great advantage. Realization of length variation slenderness ratio by changing the length of column, this paper also study the influence of slenderness ratio, the main parameters of the high-strength concrete filled high-strength square steel tube middle-long column. It is found that both bearing capacity and the plastic capacity are associated with slenderness ratio.


2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Min Gan ◽  
Yu Yu ◽  
Liren Li ◽  
Xisheng Lu

Four test pieces with different steel plate center-to-center distances and reinforcement ratios are subjected to low-cycle repeat quasistatic loading to optimize properties as failure mode, hysteretic curve, skeleton curve, energy dissipation parameters, strength parameters, and seismic performance of high-strength concrete low-rise shear walls. The embedded steel plates are shown to effectively restrict wall crack propagation, enhance the overall steel ratio, and improve the failure mode of the wall while reducing the degree of brittle failure. Under the same conditions, increasing the spacing between the steel plates in the steel plate concrete shear wall can effectively preserve the horizontal bearing capacity of the shear wall under an ultimate load. The embedded steel plates perform better than concealed bracing in delaying stiffness degeneration in the low-rise shear walls, thus safeguarding their long-term bearing capacity. The results presented here may provide a workable basis for shear wall design optimization.


2016 ◽  
Vol 711 ◽  
pp. 564-571 ◽  
Author(s):  
Thomas Gernay

The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.


2012 ◽  
Vol 479-481 ◽  
pp. 2041-2045
Author(s):  
Yue Qi

Based on experimental research on plain concrete columns with high strength concrete core, the formula to predict the bearing capacity of concrete columns with high strength concrete core under axial compression loading was brought forward in previous paper, in order to verify the formula whether right, axial compression test including 3 concrete columns with high strength concrete core and 1 ordinary reinforced concrete column were completed, and the failure characteristic was analyzed additionally. According to experimental results, it can be shown that the failure modes of concrete columns with high strength concrete core are similar to that of ordinary reinforced concrete columns, however, the bearing capacity of concrete columns with high strength concrete core is significant higher compared with that of ordinary reinforced concrete column; the results of the bearing capacity obtained by the formula (2) was in good agreement with the experimental results.


2019 ◽  
Vol 5 (7) ◽  
pp. 1440-1451
Author(s):  
Ernesto Fenollosa ◽  
Iván Cabrera ◽  
Verónica Llopis ◽  
Adolfo Alonso

This article shows the influence of axial force eccentricity on high strength concrete columns design. The behavior of columns made of normal, middle and high strength concrete with slenderness values between 20 and 60 under an eccentric axial force has been studied. Structural analysis has been developed by means of software which considers both geometrical and mechanical non-linearity. The sequence of points defined by increasing values of axial force and bending moment produced by eccentricity has been represented on the cross-section interaction diagram until failure for each tested column. Then, diagrams depicting the relationship between failure axial force and column's slenderness have been drawn. The loss of bearing capacity of the member for normal and middle strength columns when compared with the bearing capacity of their cross-section is more noticeable as axial force eccentricity assumes higher values. However, this situation reverses for high strength columns with high slenderness values. On the basis of results obtained, the accuracy level for the moment magnifier method was checked. Despite the good concordance in most of the cases, it was verified that the moment magnifier method leads to excessively tight results for high strength concrete columns with high slenderness values. In these specific cases, a coefficient which amends the column rigidity is proposed so as to obtain safer values.


2019 ◽  
Vol 2019 ◽  
pp. 1-22 ◽  
Author(s):  
Yu Yu ◽  
Min Gan ◽  
Yan Zhang ◽  
Liren Li ◽  
Huakun Zhang

To study the antiseismic performance of the high-strength concrete composite shear wall with built-in steel plates, an experiment on a high-strength concrete composite shear wall with four built-in steel plates (SPRCW-1∼4) was set up. Based on the experimental result, the paper discusses the antiseismic performance, failure mode, and failure mechanism of the high-strength concrete composite shear wall with built-in steel plates under different steel ratios and different positions of steel plates. The experimental result has shown that the differences in steel plate position and steel ratios have certain effects on wall cracking. The use of high steel content and the placement of steel plates on both sides of the wall can limit wall cracking to some extent. When the bearing capacity of the steel plates located on both sides of the wall is larger than that in the middle of the wall, a high content of steel in the wall can effectively increase the bearing capacity of the test piece to some extent. Under a high axial compression ratio, the horizontal bar of the wall can substantially limit the vertical cracks in concrete arising from compression. Moreover, the built-in steel plates in the shear wall play a significant role in inhibiting the propaganda of the oblique cracks under the action of earthquakes. The research result has very good economy and operability and can provide a basis for promotion and application of the mid- and high-rise buildings in regions with high seismic intensity.


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