Centrifuge testing and numerical analysis of box culverts installed in induced trenches

2010 ◽  
Vol 47 (2) ◽  
pp. 147-163 ◽  
Author(s):  
Benjamin L. McGuigan ◽  
Arun J. Valsangkar
Keyword(s):  
Soil Structure ◽  
Earth Pressure ◽  
Centrifuge Testing ◽  
Centrifuge Tests ◽  
Earth Pressures ◽  
Box Culverts ◽  
Box Culvert ◽  
Contact Pressures ◽  
Base Contact ◽  
Good Agreement

Induced trench construction is routinely used for circular conduits, but its application for box culverts is less common. To understand the complex soil–structure interaction issues related to the design of induced trench box culverts, centrifuge tests were performed to measure earth pressures on a model box culvert installed in several induced trench configurations. These tests were modelled with FLAC and good agreement was achieved. A parametric study performed with FLAC identified a preferred compressible zone geometry having a width of 1.2 times the culvert width and a thickness of 0.5 times the culvert height. For this geometry, the earth pressure on the top was 0.28 times the overburden, the lateral earth pressure on the sides was 0.47 times the mid-height overburden, and the contact pressure at the base was 0.73 times the overburden plus the pressure from the dead load of the culvert. The average base contact pressures for the induced trench geometry were 35% lower than those for the corresponding positive projecting case. The induced trench method, therefore, appears to be a viable option for box culverts installed under high embankments.

Earth pressures exerted on an induced trench cast-in-place double-cell rectangular box culvert

2012 ◽  
Vol 49 (11) ◽  
pp. 1267-1284 ◽  
Author(s):  
Olajide Samuel Oshati ◽  
Arun J. Valsangkar ◽  
Allison B. Schriver
Keyword(s):  
Earth Pressure ◽  
Test Results ◽  
Overburden Pressure ◽  
Centrifuge Testing ◽  
Geotechnical Centrifuge ◽  
Drag Forces ◽  
Field Instrumentation ◽  
Earth Pressures ◽  
Box Culvert ◽  
Base Contact

Earth pressure data from the field instrumentation of a cast-in-place reinforced rectangular box culvert are presented in this paper. The instrumented culvert is a 2.60 m by 3.60 m double-cell reinforced cast-in-place rectangular box buried under 25.10 m of fill constructed using the induced trench installation (ITI) method. The average earth pressure measured across the roof was 0.42 times the overburden pressure, and an average of 0.52 times the overburden pressure was measured at mid-height of the culvert on the sidewalls. Base contact pressure under the rectangular box culvert was also measured, providing field-based data demonstrating increased base pressure resulting from downward drag forces developed along the sidewalls of the box culvert. An average increase of 25% from the measured vertical earth pressures on the roof plus the culvert dead load (DL) pressure was calculated at the culvert base. A model culvert was also tested in a geotechnical centrifuge to obtain data on earth pressures at the top, sides, and base of the culvert. The data from the centrifuge testing were compared with the prototype structure, and the centrifuge test results agreed closely with the measured field prototype pressures, in spite of the fact that full similitude was not attempted in centrifuge testing.

Field performance, centrifuge testing, and numerical modelling of an induced trench installation

2008 ◽  
Vol 45 (1) ◽  
pp. 85-101 ◽  
Author(s):  
Rodney P. McAffee ◽  
Arun J. Valsangkar
Keyword(s):  
Numerical Modelling ◽  
Pressure Distribution ◽  
Earth Pressure ◽  
Field Performance ◽  
Overburden Pressure ◽  
Centrifuge Testing ◽  
Geotechnical Centrifuge ◽  
Earth Pressures ◽  
Prototype Structure ◽  
Box Culvert

The field performance of an induced trench installation is compared to the results of centrifuge testing and numerical modelling. The measured vertical pressure at the crown of the pipe in the field ranged from 0.24 to 0.36 times the overburden pressure. The horizontal earth pressures measured in the field at the springline level determined a coefficient of lateral earth pressure between 0.39 and 0.49. The culvert was monitored over a period of 2 years following completion of embankment construction indicating no measurable changes in earth pressures and deformations. A model box culvert simulating the prototype height of soil cover, the pipe width, and the thickness of the compressible layer was tested using a geotechnical centrifuge. The prototype structure was also evaluated using numerical modelling to predict full earth pressure distribution and deformations. A comparison of field data, centrifuge testing, and numerical modelling shows that the Marston–Spangler theory used in designing induced trench culverts is conservative. The theory however, does not address or predict the nonuniform pressures on the top, sides, or bottom of the pipe, and therefore numerical analysis should be used to estimate the complete pressure distribution.

scholarly journals Post-construction performance of induced trench rigid culverts

2016 ◽  
Vol 53 (11) ◽  
pp. 1807-1821 ◽  
Author(s):  
Benjamin L. McGuigan ◽  
Olajide Samuel Oshati ◽  
Bethanie A. Parker ◽  
Arun J. Valsangkar
Keyword(s):  
New Brunswick ◽  
Case Studies ◽  
Earth Pressure ◽  
Pressure Measurements ◽  
Indirect Assessment ◽  
Earth Pressures ◽  
Box Culverts ◽  
First Results ◽  
Box Culvert ◽  
Satisfactory Manner

Induced trench construction is commonly used to reduce earth pressures on rigid circular and box culverts. Most of the reported literature pertains to the performance of induced trench culverts during construction and shortly after construction. This paper addresses the post-construction performance of induced trench culverts. First, results of field inspection reports are presented as an indirect assessment of performance of 90 induced trench culverts installed in New Brunswick that have been in service for up to 24 years. Second, earth pressure measurements are presented from three case studies where prototype installations were monitored over periods ranging from 4 to 9 years. The case studies presented include a single circular culvert, a cast-in-place double-cell box culvert, and a twin circular culvert installation. The fill heights above the instrumented structures varied from 19 to 25 m. All the available data from both the field inspections and earth pressure measurements indicate that the culverts installed in induced trenches are performing in a satisfactory manner.

Earth pressures on unyielding retaining walls of narrow backfill width

2001 ◽  
Vol 38 (6) ◽  
pp. 1220-1230 ◽  
Author(s):  
W A Take ◽  
A J Valsangkar
Keyword(s):  
Earth Pressure ◽  
Friction Angle ◽  
Retaining Walls ◽  
Centrifuge Modelling ◽  
Reasonable Estimate ◽  
Interface Friction ◽  
Centrifuge Tests ◽  
Earth Pressures ◽  
Nonlinear Calibration ◽  
Good Agreement

Arching theory predicts a significant reduction in earth pressures behind retaining walls of narrow backfill width. An extensive series of centrifuge tests has been performed to evaluate the use of flexible subminiature pressure cells in the centrifuge environment and their subsequent use to measure lateral earth pressures behind retaining walls of narrow backfill width. Although the flexible earth pressure cells exhibit hysteresis and nonlinear calibration behaviour, the extensive calibration studies indicate that stiff diaphragm type earth pressure cells may be used with replicate models to measure earth pressures. Measurements of lateral pressures acting on the unyielding model retaining walls show good agreement with Janssen's arching theory. Tests on backfills bounded by vertical planes of dissimilar frictional characteristics indicate arching theory with an average interface friction angle provides a reasonable estimate of lateral earth pressures.Key words: fascia retaining walls, silos, earth pressures, pressure cells, centrifuge modelling.

Earth pressures on twin positive projecting and induced trench box culverts under high embankments

2011 ◽  
Vol 48 (2) ◽  
pp. 173-185 ◽  
Author(s):  
Benjamin L. McGuigan ◽  
Arun J. Valsangkar
Keyword(s):  
Shear Stresses ◽  
Bending Moments ◽  
Test Results ◽  
Dead Load ◽  
The Earth ◽  
Earth Pressures ◽  
Box Culverts ◽  
Frictional Forces ◽  
Contact Pressures ◽  
Base Contact

Although twin culverts are often preferred for watercourse crossing, little is known about the earth pressures they experience under high embankments. Centrifuge test results have been used in this research to verify a numerical model used to evaluate culvert spacing and compressible zone geometry for twin positive projecting and induced trench box culverts. Lower pressures were calculated for twin positive projecting culverts than for a single culvert. For the induced trench case, one compressible zone spanning both culverts was the preferred geometry for culverts spaced at 0.5Bc and 1.0Bc (where Bc is the culvert width), while two zones 1.2Bc wide were found to be optimal for 1.5Bc spacing. The twin configurations generally resulted in slightly higher vertical and lower lateral earth pressures than a single culvert configuration. The base contact pressures were 25%–76% greater than the top pressure plus dead load because of shear stresses mobilized along the sidewalls; however, they were 41%–47% lower than the pressures for positive projecting configurations. The maximum bending moments calculated for the induced trench culverts were 54%–59% lower than for the positive projecting ones. Induced trench construction therefore appears to be viable for twin box culverts, provided that frictional forces along the sidewalls are taken into account.

scholarly journals Effect of Haunch on the Stresses of Box Culvert

2019 ◽  
Author(s):  
Osama Hussien
Keyword(s):  
Earth Pressure ◽  
Cost Comparison ◽  
Design Parameters ◽  
Percentage Reduction ◽  
Design Flood ◽  
The Road ◽  
Box Culverts ◽  
Earth Embankment ◽  
The Cost ◽  
Box Culvert

Culverts are often required under earth embankment to allow for the crossing of a watercourse, like streams, to prevent the road embankment from obstructing the natural waterway. The opening of the culvert is determined based on the waterway required to accommodate the design flood, whereas the thickness of the culvert section is designed based on the loads applied to the culvert. This paper studies some design parameters of box culverts, such as the thickness of the haunch, the coefficient of earth pressure, the thickness of box culvert, and depth of fill on the top slab, to show the effect of haunch on the stresses of the box culvert. The study investigated the variation in stresses and the cost comparison made for different width of the box culvert. The percentage reduction in the cost of culvert based on the presence of haunch is presented.

Seismic soil–culvert interaction

2015 ◽  
Vol 52 (11) ◽  
pp. 1649-1667 ◽  
Author(s):  
Osama Abuhajar ◽  
Hesham El Naggar ◽  
Tim Newson
Keyword(s):  
Seismic Design ◽  
Soil Cover ◽  
Numerical Models ◽  
Experimental Program ◽  
Bending Moments ◽  
Earthquake Intensity ◽  
Ground Shaking ◽  
Centrifuge Tests ◽  
Earth Pressures ◽  
Box Culverts

Box culverts may be constructed in active seismic areas, where ground shaking or ground failures can impose considerable earth pressures on them. In this study, the seismic response of box culverts was investigated experimentally and numerically. A series of scaled centrifuge tests was performed and subjected to three different earthquake signals, with different amplitudes and frequencies. Two values of culvert wall thickness and two values of sand relative density were considered in the experimental program. Experimental results are presented in terms of comparisons of seismic bending moments. These results were used to calibrate and verify two-dimensional numerical models developed using the computer program FLAC. The verified models were then used to investigate the effect of earthquake intensity and frequency, height of soil cover, and culvert thickness on the seismic bending moments for the different culvert sections. Based on the analysis results, charts are presented to aid in the seismic design of box culverts.

Parametric Study for Design and Analysis of Box Culvert by Using Newton's-Raphson Method and MATLAB Software

2020 ◽  
Vol 870 ◽  
pp. 11-19
Author(s):  
Layth Abdul Rasool Al Asadi ◽  
Hussein Shakir Al Bahrani ◽  
Luay Kadhim Al Waeli
Keyword(s):  
Earth Pressure ◽  
Design Parameters ◽  
Matlab Software ◽  
Discharge Water ◽  
Different Types ◽  
Box Culverts ◽  
Box Culvert ◽  
Earth Fill ◽  
Pressure Factor ◽  
Raphson Method

Box culverts are the monolithic unit build to pass across railway lines, roadways, etc. earthworks are made to balance the discharge water on both sides. Box takes different types of loads created by a cushion, traffic, water, soil, etc. This paper deals with the optimum design of box culvert by using Newton's-Raphson Method and AppDesigner in MATLAB Software R2017a and studies the design parameters such as the influence of depth of earth fill at the top slab of the culvert, earth pressure, factor Dead Load, Live load, effective width, etc. In this paper, the study of the box-culvert with normal and minimum cushion analyzed for different classes of loadings and conclusions made on the basis of Newton's-Raphson Method normal and minimum cushion and normal cushioning cases.

scholarly journals Comparative Analysis of Two cell and Three cell Box Culvert for Different Aspect Ratio

2021 ◽  
Vol 9 (10) ◽  
pp. 136-143
Author(s):  
Gaurav Shrivastava
Keyword(s):  
Aspect Ratio ◽  
Impact Load ◽  
Soft Soil ◽  
Limit State ◽  
Earth Pressure ◽  
Traffic Load ◽  
Soil Conditions ◽  
Natural Stream ◽  
Box Culverts ◽  
Box Culvert

Abstract: Culverts serves primarily as the hydraulic conduits conveying water from one side of a roadway or similar traffic embankment to the other; therefore, culverts serves the dual purposes of functioning as hydraulic structures as well as acting as traffic load bearing structures. They are normally cheaper than bridges, which make them the natural stream passes through channels. Box culvert are most stable and safe among various types of culverts. It can be constructed for soft soil conditions also. Therefore these are the best alternative to the major bridges for the small span and for cross drainage situation. In this work, we analyze the R.C. box culvert of two cell and three cell with different L/H ratio with the use of STAAD Pro software. In this study, we consider the span of culvert bridge as 10 m and we done the analysis for two cell and three cell culvert on the same span and varies the height with respect to span of the culvert bridge for different aspect ratio. Here we considered the traffic loading of Class AA loading as per IRC:6 2014 and also consider all the loading conditions as per IS codes. The structure designing includes the considerations of pressure cases (Box empty, Full, surcharge load) and factors such as Impact load, Braking force, Dispersal of load through fill, Effective width, Coefficients of earth pressure, Live load etc. The analysis of structure as per limit state method IS 800-2007. The IS standard requirements in the design manual for roads and bridges (IRC6-2014, IS 112-2011) is used in the structural designing of concrete box culverts. The structural elements of two cell and three cell Box culverts are compared with respect to its maximum moments respectively for the different L/H ratio on the same span of the culvert. In the results we conclude that the moments are less than the two cell Box culvert with comparison to three cell Box culvert for the constant span of both the cases of culverts. In the present study, this paper provides full discussion on the provisions in the codes, considerations and justifications of all the above aspects of design. Keyword: Box culvert, aspect ratio, Staad pro, IRC codes.

Scaled physical and numerical modelling of static soil pressures on box culverts

2015 ◽  
Vol 52 (11) ◽  
pp. 1637-1648 ◽  
Author(s):  
Osama Abuhajar ◽  
Tim Newson ◽  
Hesham El Naggar
Keyword(s):  
Side Wall ◽  
Soil Pressure ◽  
Soil Arching ◽  
Overburden Pressure ◽  
Relative Stiffness ◽  
Centrifuge Tests ◽  
Box Culverts ◽  
Interaction Factors ◽  
Box Culvert ◽  
Interaction Problem

The response of buried box culverts is a complex soil–structure interaction problem, where the relative stiffness between the soil and structure is a critical factor. In addition, soil arching is an important aspect of the soil–culvert interaction problem. A series of static scaled physical model centrifuge tests were performed to investigate soil–culvert interaction. Two different box culvert thicknesses and Nevada sand specimens with different relative densities were used to explore the interaction between the sand and box culverts under different conditions. The static loading consisted of the self-weight from the soil body. The responses of the box culvert were recorded for all loading conditions. The results were evaluated in terms of bending moment, soil pressure, and soil–culvert interaction factors. Soil pressures were evaluated using different experimental methods, which provided comparable results. The soil pressure observed on the culvert top slab showed parabolic distribution, i.e., higher values at the edges and lower at the centre than the theoretical vertical soil (overburden) pressure. The horizontal soil pressure on the side wall increased with depth. The soil–culvert interaction factors decreased at the centre and increased at the edges of the top slab, as the thickness and relative stiffness of the culvert decreased.

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