NCHRP 20-7
Proposed Research Needs Statement
Subcommittee on Bridges and Structures, T-13 Culverts
Ray M. Trujillo, P.E., NMDOT
Chair - T-13 Culverts
9/15/2015
TITLE
Make Improvements and upgrades to the CANDE Graphical User Interface.
BACKGROUND / NEEDS STATEMENT
CANDE, an acronym derived from Culvert ANalysis and DEsign, is a finite element program dedicated to the structural design and analysis of buried culverts applicable to all sizes, shapes and types of culvert materials including corrugated metal, reinforced concrete and plastics. First introduced in 1976 under the sponsorship of FHWA, CANDE is today’s tool of choice due to the trustworthiness of the program earned over 40 years of testing and improvement. The last official update was sponsored by AASHTO via NCHRP Project 15-28 and is called CANDE-2007 (with 2011 upgrade for 64-bit computers). In addition to new modeling capabilities such as large deformation analysis, LRFD design methodology, and multiple culvert systems, the hallmark of CANDE-2007 was the incorporation of a Graphical User Interface (GUI) for pre- and post-processing data that finally made the program user friendly and a viable tool for State DOT engineers and their consultants. This proposed NCHRP 20-07 project is focused on improvements and upgrades to the AASHTO-sponsored GUI.
RESEARCH OBJECTIVE
1) Produce a new official AASHTO/TRB version called CANDE-2016 to include the industry- sponsored contributions listed above that are fully integrated with the GUI.
2) Improve and correct CANDE’s GUI for all user-observed issues since the first release in 2007.
Priority of research funding will be in the order of the objectives as listed.
WORK TASKS
Tasks anticipated in this project include the following:
· Survey the CANDE user community to identify all existing GUI issues with CANDE-2007, and to prioritize all proposed improvements.
· Collate and synthesize survey results with planned GUI improvements for the industry-sponsored capabilities and develop a detailed work plan to achieve user-defined objectives.
· Present a detailed work plan to NCHRP panel including summary of survey results, planned GUI improvements and screen views for industry-sponsored capabilities.
· Revise detailed plan per comments from NCHRP panel and undertake the development of CANDE-2016 program. This task includes implementing the latest versions of Microsoft Development Studio and Intel Fortran Compiler.
· Edit and update CANDE-2016 Guideline and User Manual, Solutions and Formulations Manual, and Tutorial of Applications Manual.
· Beta-test CANDE-2016 program through a combination of volunteers from NCHRP panel members, CANDE user community, and contractor personnel.
· Disseminate the final CANDE-2016 program and documentation via the TRB/NCHRP web site, conduct TRB webinars, and outreach to relevant programs within TRB/SHRP.
URGENCY
Industry sponsors have generously agreed to share the above modeling capabilities with the entire CANDE user community via a beta version called CANDE-2015 that is freely available at the CANDE website. However, the new capabilities have not been incorporated into the AASHTO- sponsored GUI, neither the input wizard nor the output graphic options. Consequently, many State DOT engineers are inhibited from taking advantage of the new capabilities. Clearly, there is a strong need to incorporate the industry-sponsored new capabilities listed below with the AASHTO-sponsored GUI. This need forms the first objective, whereas the second objective is to correct, improve and upgrade the existing GUI capabilities.
INDUSTRY-SPONSORED NEW CAPABILITIES
Currently, there are approximately 200 registered CANDE users including over 60 engineers from state DOTs, along with engineers from industry, consulting firms, and academia. After the release of CANDE- 2007, several industries sponsored further developments of new modeling capabilities listed below:
· Conrib pipe type. This is a new pipe type with modeling capabilities for rib-shaped reinforced/concrete cross-sections. Also, the concrete stress-strain model has the ability to model fiber reinforced concrete.
· Contube pipe type. This is another new pipe type that permits modeling circular-shaped concrete cross sections encased in fiber-reinforced plastic tubes spaced at uniform distances. Useful for new soil-bridge systems and piles in conformance with AASHTO LRFD Guide Specs.
· Link elements with death option. Links are useful for connecting one beam-element group to another in either a pinned connection or fixed-moment connection. Also, the link element offers a death option that allows simulating strut removal, culvert erosion, and creation of soil voids.
· Deeply corrugated steel structures. CANDE’s corrugated steel pipe type now includes the new AASHTO combined moment-thrust design criterion and new global buckling equation for deeply corrugated steel structures. Also, the plastic-penetration algorithm has been improved.
· Variable plastic profile properties. The input data defining plastic profile section properties has been expanded to allow variable profile geometry around the pipe’s periphery. This is useful for arch-shaped storm-water chambers that vary the plastic profile geometry from top to bottom.
· Mohr/Coulomb plasticity model. The classical Mohr/Coulomb elastic-perfectly plastic model is now included in the suite of available constitutive models that may be assigned to continuum elements to describe soil behavior. Model parameters include elasticity parameters Young’s modulus and Poisson ratio and plasticity failure surface parameters cohesion and friction angle.
· Modified Duncan/Selig model for plastic-like behavior. A new modified Duncan/Selig model is now available that produces permanent deformations upon unloading similar to advanced plasticity models. In contrast, the original Duncan/Selig model is nonlinear elastic thereby retracing the same stress-strain path in loading and unloading. The user has the option to use either the Original or Modified version.
Industry sponsors have generously agreed to share the above modeling capabilities with the entire CANDE user community via a beta version called CANDE-2015 that is freely available at the CANDE website. However, the new capabilities have not been incorporated into the AASHTO- sponsored GUI, neither the input wizard nor the output graphic options. Consequently, many State DOT engineers are inhibited from taking advantage of the new capabilities. Clearly, there is a strong need to incorporate the industry-sponsored new capabilities with the AASHTO-sponsored GUI. This need forms the first objective, whereas the second objective is to correct, improve and upgrade the existing GUI capabilities.
FUNDING REQUESTED AND TIME REQUIRED
It is estimated that this research will take 12 months to complete and will require $100,000.
CONTACT PERSONS
Ray M. Trujillo, P.E.
Subcommittee Chair - T-13 Culverts
Bridge Bureau Chief, New Mexico Department of Transportation
1120 Cerrillos Rd Santa Fe, NM 87504
Phone: 505-827-5448
Fax: 505-827-5345
John Schuler, Virginia DOT
804/328-3140
Jeffrey Syar, Ohio DOT
614/275-1373
James Brennan, Kansas DOT
785/291-3858
Jason Hastings, Delaware DOT
302/760-2310
Robert Watral, Pennsylvania DOT
717/346-5974
Adam Price, Tennessee DOT
Mark Szewcik, Washington DOT
Kellie Bordeaux, Oregon DOT