NCHRP 15-54sp.bridges.transportation.org/Documents/2016... · 2017. 1. 27. · NCHRP Program. Data reported are work in progress. The contents of this presentation has not been reviewed

T. J. McGrath, Ph.D. M.G. Katona, Ph.D.

NCHRP 15-54AASHTO T-13 UpdateTHOMAS P. MURPHY, PHD, P.E. – MODJESKI & MASTERS

(FOR) MARK MLYNARSKI, P.E. – MICHAEL BAKER INTERNATIONAL


Disclaimer

This investigation was sponsored by TRB under the NCHRP Program. Data reported are work in progress. The contents of this presentation has not been reviewed by the project panel or NCHRP, nor do they constitute a standard, specification, or regulation.


Overview of Research Effort Survey Results Literature Review Analysis

3D Efforts2D Efforts

Field Testing Q&A


Survey - General

Timeframe August/SeptemberNumber of responses: 4216 Interviews conducted


SurveyResponses – Coverage: 37 states


SurveyResults

Concrete culverts used extensively


SurveyResults – Notable Items Several states reporting concrete culverts

not rating well (yet no distress observed) Seven states are using ODOT’s metal

corrugated spreadsheet Large fill heights often present a problem

– culverts fail under DL (shouldn’t be a load rating issue)

AASHTOWare BrDR used by many states for culvert rating

Several states use BRASS


Literature Review


Culvert Types Concrete

Pipe – circular and arch

box sections and flat topped 3-sided

Arches and arch topped 3-sided

Metal Pipe (round, arch, pear, high profile)

Open bottom – box and arch

Long-span – (with and without stiffeners)

Deep corrugated

Plastic Corrugated, solid wall

Literature Review


Data collected as part of Survey Effort Collection of CalTrans BrDR culvert

filesParametric study140 files (each with varying covers)

Tennessee BRASS files Other BrDR files

Literature Review


Analysis/Modelling3D AND 2D MODELING


3D Modeling Objectives

Better capture structural behavior and non-linear effects including Soil Structure Interaction

Relate/Calibrate Detailed 3D models to 2D analyses such that most of the analytical work can be done in 2D, i.e., CANDE

2D more efficient Automation possible

3D modeling of Field Testing culverts – better understanding of data obtained from field

Analysis/ Modeling


3D Modeling Procedures

Non-Linear analysis required due to materials (cracked concrete, soil), multiple loading stages and culvert buckling

Shell elements used for culverts and pavements Solid elements with Mohr-Coulomb failure criteria

for surrounding soil Loading due to culvert self-weight, soil, and truck

wheel loads Culvert modeled for full length along axis of

culvert, transverse and vertical directions similar to that used in previous NCHRP studies

Analysis/ Modeling


3D Models - Next Steps

Document detailed approach for 3D modeling of culverts, including non-linear analysis properties

Initial development of 3D models of selected existing culverts to compare with experimental results

Perform necessary analyses and provide information to those performing CANDE analysis for calibrating of 2D CANDE models to 3D LUSAS models.

Analysis/ Modeling


2D Models

Use of 2D for this project.CANDE AASHTOWare BrDROhio DOT spreadsheet (steel)

Analysis/ Modeling


2D ModelsHow are they used?CANDE Relate/Calibrate Detailed 3D

models to 2D analyses such that most of the analytical work can be done in 2D, i.e., CANDE

2D more efficientAutomation possible

Analysis/ Modeling


2D ModelsSummary CANDE Modifications

Full Mesh Option Allows Non-symmetric Loading (such as multiple

wheel loads)

Pavement Analysis Moving Loads

Up to 10 Axles

Permanently Minimize Bandwidth Increase speed for parametric studies/automation

Extract Load Rating Results Including controlling load position

Analysis/ Modeling


2D ModelsHow are they used?AASHTOWare BrDRODOT SpreadsheetRegression TestingProposing a simplified spec

from a more complex analysis and seeing how it works in practice

Analysis/ Modeling


2D ModelsHow are they used? Regression Testing

Run with current spec (benchmark)Modify for proposed revisionsCompare the regressionRegression tool – NCHRP 12-50

processHave received AASHTO’s permission

to use BrDR for this project

Analysis/ Modeling


EVALUATING PAVEMENT INFLUENCEIN LOAD-RATING BURIED CULVERTS

A Preliminary StudyforNCHRP 15-54

Analysis/ Modeling


OBJECTIVE and SCOPE

ObjectiveUsing CANDE, investigate influence of pavement stiffness on load-rating factor RF due to in-plane load spreading. (Out-of-plane load spreading is not considered in this study.)

Scope1. Pavement conditions:

● None● Modest (thickness = 8”, modulus = 200,000 psi)● Heavy (thickness = 12”, modulus = 1,000,000 psi)

2. Vehicle classes: (moving)● HL93 Design truck (72 kips, 3 axles, 14’ heavy-axle spacing)● HL93 Tandem truck (58 kips, 3 axles, 4’ heavy-axle spacing)

3. Culvert installations (6’ diameter, 2’ soil cover):● Reinforce concrete● Corrugated steel● Plastic profile pipe

Analysis/ Modeling


ILLUSTRATION of CANDE MODELS

Models = (2 Truck classes) x (3 Culvert types) x (3 Pavement conditions) = 18

Moving vehicles = 5 positions of middle axle to find max culvert distress

Analysis/ Modeling


Summary of Pavement Influence

Pipe Type

RF % increaseVersus No Pavement

Modest Pavement

HeavyPavement

Steel 147%24%

183%78%

Concrete 42%2%

71%47%

Plastic 63%49%

111%145%

Design Truck Tandem Truck



Pavement models can improve RF load rating.

Analysis/ Modeling


Pavement Issues to be Explored

• Pavement modulus values (e.g. temperature effect of asphalt pavement)

• Influence of backfill stiffness, methods of determining backfill stiffness.

• Characterization of Pavement Condition

Analysis/ Modeling


Field Testing


Field Testing Survey yielded information on testing conducted by other

states Testing performed in Kansas, Missouri, Delaware, others Make use of prior test results where possible Participating states have provided lists of potential culverts Review plan sets from lists of culverts provided by DOTs

Field Testing


Field Test Objectives

Evaluate special conditions Pavement – new and old

Aging culverts

Evaluate conservatism in design methods Provide data for computer model validation

Field Testing


Criteria used for site selection

Structures that are not rating properly Structures with low fill depths No plastic pipe

MN-DOT study indicates good performance

Not widely used under high volume roads

Field Testing


Initial Target StructuresMajor group Sub-group Category Typical Sizes

(ft)Target Test Structures

Reinforced concrete

Box sections Precast 4-20+ 8-12 ft spans

CIP 4-20+ 10-20 ftPipe <12Three-sided Flat top <30

Arch top <48 24-36 ft span

Arches Precast >10CIP >10

Corrugated metal

Pipe <12 10 ft diameter

Long-span 6x2 <30 30 ft spandeep corr. <75 40 ft span

Box sections 6x2 steel/alum. <366x2 steel/alum. <25deep corr. <23

Field Testing


Current targets

Concrete boxes Use for pavement evaluation Use for new vs old evaluation

Metal arches 6 x 2 corrugations, low fill

Metal box sections Large top radius, controlled by flexure

Field Testing


Field test challenges

Getting comparable data for pavement evaluation

Monitoring concrete box sections (low strains and displacements)

Field Testing


Q&A