Modernize and Upgrade CANDE for Analysis and LRFD Design of Buried Structures (2008)

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S U M M A R Y This report highlights the work accomplished under the AASHTO-sponsored project entitled “Modernize and Upgrade CANDE for Analysis and Design of Buried Structures” administered by the National Cooperative Highway Research Program as NCHRP Project 15-28. The research effort has produced a significantly enhanced version of the original CANDE software with many new analysis capabilities, a graphical user interface (GUI), explanatory tutorials demonstrating the various program applications, and a comprehen- sive context-sensitive help system. CANDE-2007 is a special purpose finite element program developed for the structural design and analysis of buried culverts. The finite element methodology is based on a two- dimensional (2-D) slice of the culvert installation so that both the culvert structure and soil zones are modeled as a combined soil-structure system subjected to an incremental loading schedule. Buried culverts of any shape, size, and material, including corrugated metal, rein- forced concrete, and thermoplastic pipe, may be analyzed and designed to withstand dead weight, incremental soil-layer loading, temporary construction loads, and surface loads, due to vehicular traffic. A particularly unique feature of CANDE’s output is the automatic eval- uation of the structural performance in terms of safety measures against all failure modes (design criteria) associated with the structural material. New analysis capabilities include the following: • Multiple pipe-type analysis and design, • Large deformation formulation with buckling capacity prediction, • Load resistance and factor design (LRFD) methodology, and • Automated bandwidth minimization and several other special utility options. A new GUI offers the following: • An integrated windows interface with menu-driven input and error checking, • Graphical viewing options for the finite element mesh, • Interactive graphing options for the beam element responses, • A dynamic report generator, and • A context-sensitive help system. The research team, the NCHRP 15-28 panel, and a group of beta-tester volunteers have extensively tested CANDE-2007. The program is judged to be robust, accurate, and the tool- of-choice for culvert analysis and design. Modernize and Upgrade CANDE for Analysis and Design of Buried Structures 1

2Deliverables from this research project include the CANDE-2007 software program and three stand-alone documents in addition to this report (available as NCHRP CD-ROM 69). The documents are entitled as follows: • CANDE-2007 User Manual and Guideline, • CANDE-2007 Solution Methods and Formulations, and • CANDE-2007 Tutorial of Applications. Engineers, researchers, and designers from state DOTs, consulting firms, manufacturers, universities, and research institutions are encouraged to use CANDE-2007 for all culvert design and analysis problems. CANDE-2007 is a public-domain program.