Mdx curved steel girder alanbridge structural op 31 aug 07 17. Mdx software is the developerdistributor of the curved and straight steel bridge design and rating package, which is used for designing and rating steel girder bridges for compliance with aashto asd, lfd, and lrfd specifications. Highway bridges for allowable stress design asd and load. Mdx, a commercially available bridge design and rating analysis program.
Michael bakers approach to complex steel load rating midas. Analytical and field investigation of horizontally curved girder bridges. For nonstandard userdefined or ns flange dimensions and material allowable stresses can be provided by the. The result flange flange check command will display the flange analysis dialog, enabling the user to apply several different flange analysis methods on every flange in the model. I have used bsdi on another project, and compared it too a sap fe analysis and the results were near identical.
The question is, what are the some of the limitations of mdx regarding capturing the behavior of the cross frames. Static vertical bending stresses for the top and bottom. What are some of the most pertinent issues that i should be aware of as i use mdx. A data item flgtrans, for flange transitions, has been implemented to move the stress check on the weak side of a flange splice a distance away from the splice. Mdx support is not mdx for steel beam concrete deck bridge structural engineering general discussion engtips.
The nozzle opening length was more than 2x its width so according to ug36a1 additional analysis is required beyond the standard area replacement rules. Its because the model type directly affects the bending stresses. Flange lateral bending stress f under the wind pressure. Mdx curved steel girder structural engineering general.
Interim revisions to aashto lrfd bridge design specifications 7 th edition were published in 2016 with a few minor revisions to the steel bridge design sections of the specifications. The computer program descus ii will perform the complete analysis of a horizontally curved bridge composed of steel box sections which act either compositely or noncompositely with a concrete deck. Girder design s generates a girder design in line girder design projects, and generates a design for either a particular girder or a design for each girder in girder system design projects. The agency i am designing for, prefers mdx as it suits their load rating methodology. Bolted crossframe connection bridge engineering engtips. Flange lateral bending stress technical knowledge base. Dead load stress comparisons for interior girder c. The problem was with bottom flange factored bending stresses and ratings. Prior to march 1, 2010 only those significant fixes that could cause overstressing or significant changes to deflections defined as class 1 below as determined by the results of this test. I am looking to use mdx to design a multispan steel girder bridge. Top flange stress incorrectly used in numerator of lrfd d6. The 8 th edition of aashto lrfd bridge design specifications is expected to be published later in 2017. Using a modular ratio of n typically gives higher stresses in the concrete.
Both comp and noncomp lateral bending stress sometimes included in comp dead stress for rating table. Aashto standard specification for allowable stress design asd and load. Curved highway bridges in an allowable stress design format 1, which were. Mdx software problems fixed software changes are run through a test suite of approximately 50 bridge projects to determine how much impact such changes might have to a variety of project parameters. Chapter 4 discusses the grillagebased computational software, umn program, which was used. Pdf examination of level of analysis accuracy for curved igirder. Lvdt to measure slip between top flange and concrete slab. Correct value can cause overstress for deep girders where slab is assumed active for service ii negative bending.
Flange lateral bending stresses for design requests involving bridge object igirders are evaluated only for models in which the bridge girders are modeled either by shell elements for both the webs and the flanges or by shell elements for webs and frame elements for the flanges. Flange lateral bending stress fl under the wind pressure by atorod azizinamini, ph. Flange lateral bending stress along length of girder 8 of bridge a. Standard flange data can be recalled from dimension and material libraries. The program can use either the working stress design wsd method, the load factor design lfd method or the load and resistance factor design lrfd method. Steel girder design example using 3rd edition aashto lrfd. The study made conclusions comparing the three methods of analysis against one. To sum up this bridge, it is a single span plate girder 128. This sample head is from a job where our customer wanted to put a nozzle at the sphere to knuckle junction. Hello all i am trying to use mdx to design a steel beam concrete slab bridge and wanted to get some help with several aspects of the design. As far as steel bridge design is concerned, a major revision to the design of bolted field splices and.
Bsdi will be used to check the mdx analysis, mdx will be used to do the final design. We understand with mdx output forces are high in the magnitude of 23 times. Lrfd steel girder superstructure design example lrfd. Systemmodeler improves connection to various cae software. Load rating of composite steel curved igirder bridges. Mdx for steel beam concrete deck bridge structural. Steel plate girder diaphragm and crossbracing loads fdot.
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