Implementation of the tangent modulus – vertical stress (Et–σv) model for flexible pavements analysis

2006 ◽  
Vol 43 (11) ◽  
pp. 1131-1143
Author(s):  
J -M Konrad ◽  
Ph D Nguyen
Keyword(s):  
Finite Element ◽  
Granular Material ◽  
Vertical Stress ◽  
Load Test ◽  
Tangent Modulus ◽  
Quebec City ◽  
Elastic Model ◽  
Loading Test ◽  
Test Plate ◽  
Plate Load Test

A recently developed nonlinear elastic model of granular material, referred to as the tangent modulus – vertical stress (Et–σv) model, was implemented into a finite element numerical solver FlexPDE. The FlexPDE program was used to compare deflection predictions with actual plate-load test data from a site near Québec City. The proposed Et–σv model performed well and led to excellent predictions for load levels of 40, 50, and 70 kN. Comparison with predictions using the Uzan model suggests that constitutive models of granular materials are best expressed in terms of vertical stress rather than mean stress for the prediction of elastic pavement response for field conditions.Key words: granular material, resilient modulus, triaxial test, plate-loading test, finite element.

Observed and calculated load-settlement relationship in a sandy gravel

2000 ◽  
Vol 37 (2) ◽  
pp. 333-342 ◽  
Author(s):  
Fernando Rodríguez-Roa
Keyword(s):  
Finite Element ◽  
Constitutive Relations ◽  
Load Test ◽  
Triaxial Tests ◽  
Hyperbolic Model ◽  
Elastic Model ◽  
Stress Strain ◽  
Plate Load Test ◽  
Nonlinear Stress ◽  
Calculated Load

The purpose of this research was to obtain a better understanding of the nonlinear stress-strain behavior of the typical gravel of Santiago, Chile, due to the increasing needs for construction of high-rise buildings, multilevel underground constructions, and new subway lines to be built under historical city landmarks. A finite-element computer program to perform incremental stress-strain analyses of soils was developed on the basis of a modified version of the hyperbolic elastic model. The changes herein proposed to this well-known constitutive model were based on triaxial tests carried out on 150 mm diameter specimens of compacted sandy gravels which involved various stress paths. A comparison was performed between the observed and calculated load-settlement relationship in a plate-load test that included unloading-reloading cycles. From the good agreement obtained it is concluded that the modified version of the hyperbolic model proposed represents reasonably well the behavior of the Santiago gravel.Key words: constitutive relations, finite-element model, laboratory tests, field tests, soil properties, case history.

scholarly journals Experimental Study on Mechanical Property of Stiffening-ribbed-hollowpipe Reinforced Concrete Girderless Floor with Four Clamped Edges Supported

2013 ◽  
Vol 7 (1) ◽  
pp. 170-178 ◽  
Author(s):  
Weijun Yang ◽  
Yongda Yang ◽  
Jihua Yin ◽  
Yushuang Ni
Keyword(s):  
Mechanical Property ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Large Scale ◽  
Load Test ◽  
Static Load Test ◽  
Loading Test ◽  
Element Analysis ◽  
Clamped Edges

In order to study the basic mechanical property of cast-in-place stiffening-ribbed-hollow-pipe reinforced concrete girderless floor, and similarities and differences of the structural performance compared with traditional floor, we carried out the destructive stage loading test on the short-term load test of floor model with four clamped edges supported in large scale, and conducted the long-term static load test. Also, the thesis conducted finite element analysis in virtue of ANSYS software for solid slab floor, stiffening-ribbed-hollow-pipe floor and tubular floor. The experiment indicates that the developing process of cracks, distribution and failure mode in stiffening-ribbed-hollow-pipe floor are similar to that of solid girderless floor, and that this kind of floor has higher bearing capacity and better plastic deformation capacity. The finite element analysis manifests that, compared with solid slab floor, the deadweight of stiffening-ribbed-hollow-pipe floor decreases on greater level while deformation increases little, and that compared with tubular floor, this floor has higher rigidity. So stiffening-ribbed-hollow-pipe reinforced concrete girderless floor is particularly suitable for long-span and large-bay building structure.

Static Loading Test of the End-Bearing Pile under the Sides Friction Action

2013 ◽  
Vol 353-356 ◽  
pp. 974-978
Author(s):  
Xiao Wei Wang ◽  
Nan Gai Yi ◽  
Shi Ping Zhang
Keyword(s):  
Finite Element ◽  
Load Test ◽  
Practical Significance ◽  
Engineering Practice ◽  
Single Pile ◽  
Static Load Test ◽  
Loading Test ◽  
Foundation Soil ◽  
Measuring Point ◽  
End Bearing Pile

Because the pile foundation has the characters of high bearing capacity, small deformation and easy to construct, it is widely used in practical engineering. In order to verify the end-bearing pile loading capability, in this paper, the single pile vertical compressive static load test is used to the on-site measuring point in actual engineering test, and get the Q-S curve of the pile. FEM is used to simulate the test at the same time. The ideal elastic-plastic constitutive model based on Mohr-Coulomb failure criteria is used to simulate foundation soil. Some conclusions are obtained by using large scaled finite element analysis software ADINA to build the 2D plane strain finite element model and to proceed numerical analysis of the pile. Finally, the comparative analysis with the engineering practice is proceeded. It has the practical significance for the structure analysis of the single pile.

scholarly journals Finite Element Modelling of Prestressed Concrete Piles in Soft Soils, Case Study: Northern Jakarta, Indonesia

2021 ◽  
pp. 21-30
Author(s):  
Aswin Lim ◽  
Varian Harwin Batistuta ◽  
Yiska Vivian Chritiansen Wijaya
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Coastal Area ◽  
Interface Strength ◽  
Load Test ◽  
Loading Test ◽  
Soft Soils ◽  
Concrete Piles ◽  
High Rise

Jakarta is faced with limited land resources due to its position as the capital city of Indonesia. Therefore, numerous high-rise buildings are being constructed to solve this problem and provide accommodations for a large number of Jakarta residents. Studies have shown that prestressed concrete piles (spun piles) are commonly used as the foundations of high-rise buildings in metropolitan cities across Indonesia, especially in the Northern Jakarta Coastal area, which is predominant with deep soft soils deposit. To further assess and verify the ultimate capacity of the pile, a static loading test was conducted. However, not all results from the field test produced ideal, accurate, precise, and reliable load-settlement curve (until failure) results. Therefore, this study aims to determine the soil properties for the analysis of prestressed concrete spun piles with a diameter of 600 mm in the Northern Jakarta coastal area based on the standard penetration test values (SPT-N). It is a case study of a well-documented static pile load test using the kentledge system. Back analyses were performed by the finite element method to obtain the extrapolated load-settlement curve. Furthermore, the effect of interface strength between pile and soil on the load-settlement curve was also investigated. The results showed that a reduction of interface strength leads to a smaller load–settlement curve. In addition, several geotechnical engineering parameters of soil, such as the undrained shear strength and effective young's modulus, were established using data from an in-situ soil site investigation and empirical correlations with SPT-N.

scholarly journals Using portable falling weight deflectometer to determine treatment depth of subgrades in highway reconstruction of Southern China

2020 ◽  
Vol 2 (1) ◽  
pp. 18-28
Author(s):  
Junhui Zhang ◽  
Le Ding ◽  
Ling Zeng ◽  
Qianfeng Gao ◽  
Fan Gu
Keyword(s):  
Detection Efficiency ◽  
Southern China ◽  
Field Tests ◽  
Load Test ◽  
Beam Deflection ◽  
Falling Weight Deflectometer ◽  
Test Plate ◽  
Plate Load Test ◽  
Deflection Test ◽  
Falling Weight

Abstract Based on a highway reconstruction project in southern China, this study aims to put forward a method to determine the proper treatment depth of the existing subgrade. First, some field tests including the Beckman beam deflection test and portable falling weight deflectometer (PFWD) test were carried out. The results showed that there was a good correlation between the Beckman beam deflection (L) and PFWD modulus (Ep). Subsequently, a subgrade section was excavated and backfilled with cement-stabilized soil in layers. Compaction test, dynamic cone penetrometer rate test, plate load test and Beckman beam deflection test were performed to evaluate the treatment effect. To make sure, the subgrade was treated deeply enough, the Beckman beam deflection (L) was used as the controlled indicator among all the measured indexes for it was the hardest metric to meet. According to the design deflection and decreasing law of the measured deflections with the different number of the stabilized layers, the treatment depth was finally determined. As the PFWD test is superior to the deflection test in the detection efficiency, and the deflection value can be calculated from PFWD modulus by correlation formulas, thus the latter index can be used as a more suitable parameter for estimating the treatment depth instead of the former. Consequently, based on the measured PFWD moduli of the existing subgrade, six treatment schemes considering different treatment depths were proposed. It was confirmed that the method developed from this study is feasible and worth being extensively applied.

Analysis of Dynamic Performance Testing of Bridge Based on Finite Element and Dynamic Load Test

2012 ◽  
Vol 178-181 ◽  
pp. 2323-2328
Author(s):  
Zhi Gang Lu ◽  
Guo Jian Li ◽  
Wen Wu Jiang
Keyword(s):  
Finite Element ◽  
Theoretical Analysis ◽  
Large Scale ◽  
Natural Vibration ◽  
Performance Testing ◽  
Load Test ◽  
Natural Vibration Frequency ◽  
Loading Test ◽  
Finite Element Software ◽  
The Impact

Using the Jianninxia Bridge as the experiment object, we set dynamic loading test on it, and did theoretical analysis on its natural vibration characteristics by using large-scale general finite-element software. After the comparative analysis between the collected datas and the theoretical analysis datas, we find that the measurement of the natural vibration frequency is greater than the theoretical analysis value; and the measured value of impact coefficient is less than the theoretical value; therefore, it indicates that this bridge’s actual structural rigidity is greater than its theoretical rigidity, but lack of the impact resistance.

Ultimate Load Test and Analysis of a Retrofitted Model Steel Dome

1998 ◽  
Vol 13 (2) ◽  
pp. 53-63
Author(s):  
Hewen Li ◽  
Lewis C. Schmidt
Keyword(s):  
Finite Element ◽  
Ultimate Load ◽  
Load Capacity ◽  
Load Test ◽  
Finite Element Analyses ◽  
Loading Test ◽  
Ultimate Load Capacity ◽  
Geometrical Imperfections ◽  
Hexagonal Grids ◽  
Post Tensioned

This paper concerns the test and analysis of a retrofitted post-tensioned and shaped steel dome that failed in an original loading test. The post-tensioned and shaped steel dome was formed by a post-tensioning operation from a planar layout constituted of hexagonal grids. After its first loading to failure, the dome was retrofitted in situ. The retrofitting method and the results of a subsequent ultimate load test and nonlinear finite element analyses of the retrofitted dome are presented. It is found that the retrofitted dome has a much greater ultimate load capacity than the original dome. The results of finite element analyses show that the prestress member forces caused during shape formation can cause a reduction of ultimate load capacity, and that the post-tensioned and shaped steel dome investigated here is sensitive to geometrical imperfections. It is also noted that the retrofitting process can be used to erect a domic structure from a near flat layout. The proposed method of considering prestress forces can be useful in nonlinear analysis of structures involving prestress forces.

scholarly journals Finite element analysis of double‐plate fixation using reversed locking compression‐distal femoral plates for Vancouver B1 periprosthetic femoral fractures

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Daisuke Takahashi ◽  
Yoshihiro Noyama ◽  
Tsuyoshi Asano ◽  
Tomohiro Shimizu ◽  
Tohru Irie ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plate Fixation ◽  
Weight Bearing ◽  
Femoral Fractures ◽  
Full Weight Bearing ◽  
Loading Test ◽  
Lateral Plate ◽  
Element Analysis ◽  
Periprosthetic Femoral Fractures

Abstract Background Internal fixation is recommended for treating Vancouver B1 periprosthetic femoral fractures. Although several fixation procedures have been developed with high fixation stability and union rates, long-term weight-bearing constructs are still lacking. Therefore, the aim of the present study was to evaluate the stability of a double-plate procedure using reversed contralateral locking compression-distal femoral plates for fixation of Vancouver B1 periprosthetic femoral fractures under full weight-bearing. Methods Single- and double-plate fixation procedures for locking compression-distal femoral plates were analysed under an axial load of 1,500 N by finite element analysis and biomechanical loading tests. A vertical loading test was performed to the prosthetic head, and the displacements and strains were calculated based on load-displacement and load-strain curves generated by the static compression tests. Results The finite element analysis revealed that double-plate fixation significantly reduced stress concentration at the lateral plate place on the fracture site. Under full weight-bearing, the maximum von Mises stress in the lateral plate was 268 MPa. On the other hand, the maximum stress in the single-plating method occurred at the defect level of the femur with a maximum stress value of 1,303 MPa. The principal strains of single- and double-plate fixation were 0.63 % and 0.058 %, respectively. Consistently, in the axial loading test, the strain values at a 1,500 N loading of the single- and double-plate fixation methods were 1,274.60 ± 11.53 and 317.33 ± 8.03 (× 10− 6), respectively. Conclusions The present study suggests that dual-plate fixation with reversed locking compression-distal femoral plates may be an excellent treatment procedure for patients with Vancouver B1 fractures, allowing for full weight-bearing in the early postoperative period.

scholarly journals Prediction of Effects of Geogrid Reinforced Granular Fill on the Behaviour of Static Liquefaction

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
A. Hemalatha ◽  
N. Mahendran ◽  
G. Ganesh Prabhu
Keyword(s):  
Bearing Capacity ◽  
Load Test ◽  
Test Results ◽  
Plate Load Test ◽  
Large Size ◽  
Static Liquefaction ◽  
Granular Fill ◽  
Size Dimension ◽  
Subgrade Modulus ◽  
Different Thickness

The experimental investigation on the effects of granular fill and geogrid reinforced granular fill on the behaviour of the static liquefaction potential of the subsoil is reported in this study. A series of plate load test were carried out with different thickness of the granular fill, number of geogrid layers, and size/dimension of the footing. The test results were presented in terms of bearing capacity and subgrade modulus for the settlement ofδ10,δ15, andδ20. The experimental results revealed that the introduction of granular fill significantly increases the bearing capacity and effectively control the settlement behaviour of the footing. The introduction of geogrid in granular fill enhanced the Percentage of Control in Settlement and Bearing Capacity Ratio by a maximum of 328.54% and 203.41%, respectively. The introduction of geogrid in granular fill interrupts the failure zone of the granular fill and enhances the subgrade modulus of the footing by a maximum of 255.55%; in addition subgrade modulus of the footing was increased with an increase in the number of geogrid layers. Based on the test results it is suggested that the footing with large size has beneficial improvement on the reinforced granular fill.

Study on Reinforce Saturated Soft Clay Foundation with Dynamic Consolidation by Drainage

2013 ◽  
Vol 438-439 ◽  
pp. 1171-1175
Author(s):  
Zhi Li Sui ◽  
Zhao Guang Li ◽  
Xu Peng Wang ◽  
Wen Li Li ◽  
Tie Jun Xu
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Clay ◽  
Soil Layer ◽  
Good Effect ◽  
Loading Test ◽  
Test Plate ◽  
Dynamic Consolidation ◽  
Saturated Soft Clay

Dynamic consolidation method has been widely used in improving soft land, but always inefficient to saturated soft clay land, which is hard to improve, and even leads to rubber soil. Dynamic and drain consolidation method will deal with it well, with drainage system, pore-water can be expelled instantly from saturated soft clay as impacting. The pore-water pressure and earth pressure test in construction, the standard penetration test, plate loading test, geotechnical test after construction, which are all effective methods for effect testing. There is a comprehensive detection through different depth of soil layer with different detecting means on construction site. The results show that improving saturated soft clay land with dynamic and drain consolidation method has obtained good effect, and the fruit can be guidance for such construction in the future.

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