Note that for steel tub girders, the provisions of article 6. Siteblauvelt engineers cranberry township, pa pittsburgh, pa b s d i design. Choice of deck bridge design bridge design and assessment. Two design examples of a simply supported slab bridge and a twospan box girder bridge are also presented. Typically a member taller than the minimum will be the most efficient. Example b4 global plus regional combination menn b7 e. Locate field splices at or near points of dead load contraflexure. Design aids of nu igirder bridges nebraska department of. Chances are very high that today, a bridge engineer will learn how to design a bridge girder before any other bridge type. Design of prestressed girder for bridge prestressed girder reinforcement details duration. Within the state of nebraska, the two standard precast prestressed products used are inverted tee it girders and university of nebraska nu igirders. Making the correct choice of deck will depend on many factors.
The basic application of the aashto lrfd bridge design specifications to the design of straight steel isection flexural members is illustrated through this design example. The example illustrates many aspects of the design procedures described in the earlier sections and should prove a valuable insight into the application of bs 5400 to the design of a steel railway bridge. Analysis and design of prestressed box girder bridge by. Design step 5 design of superstructure prestressed concrete bridge design example task order dtfh6102t63032 549 sample calculations at 54 ft. The example problem is a three span continuous box girder bridge that is 700 ft. Key words prestressed concrete, lrfd, design, bridge girders, u54 girder, type iv girder, type c girder, parametric study 18. Deck design follows the nmdot standard deck slab detail in chapter 4 of the nmdot bridge procedures and design guide, hereinafter referred to as design guide. A twospan continuous composite igirder bridge has two equal spans of 165 and a 42 deck width. The design example and commentary are intended to serve as a guide to aid bridge design engineers with the implementation.
Authors todd helwig, joseph yura, reagan herman, eric williamson, dawei li 8. It is assumed the bridge will be cast on falsework. Aashto lrfd bridge design specifications specific to new mexico bridge design practice so that uniformity in bridge design procedures will be attained. Four lrfd design examples of steel highway bridges, vol. Where round head bolts are required, astm a449 bolts shall be used. However, the typical load combination for superstructure design is the group i load combin ation. Abstract the purpose of this example is to illustrate the use of the aashto lrfd bridge design for the design of a continuous two span steel i girder bridge. Concrete structures chapter 5 wsdot bridge design manual m 2350. Comprehensive design example for prestressed concrete.
A plane truss girder may be considered as a deep beam where the flanges are the compression and tension chords of the truss and the web of the beam is replaced by an open triangular system which resists the shear forces. Key words igirder, curved bridge, lifting, erection, construction 18. It is a companion to a publication giving general guidance on composite highway bridge design. Design of posttensioned girder anchorage zones by w. Plan, elevation and section views are shown on the following pages. For group i, the factored load effects use a factor of 1. A design example followed by a load rating analysis illustrates the engineering computations performed by pgsuper. Crane girder design crane girder details proper detailing is the key to good fatigue performance the vast majority of crane girder performance issues occur at the crane girder to column connection. It gives two worked examples, one for a multi girder bridge and one for a ladder deck bridge. Preliminary design making the correct choice of bridge deck type reinforced concrete. Multimedia package for lrfd concrete bridge design rosa p. Wisdot bridge manual chapter 24 steel girder structures july 2019 245 24. Finally, appendix b presents a worked example of design calculations for a typical half through twotrack railway bridge. From girder end midspan of noncomposite beam girder top stress.
Simple span reinforced concrete tee beam bridge rating example. Steel girder design example using 3rd edition aashto lrfd. The use of girder as a natural bridging element is abundantly. New bridge design information is continually developing. We will be using this bridge model as a reference for analysis in staad pro beava which is meant for structural analysis of bridge. Extend bearing stiffeners the full height of the girder. Nchrp project number 1271 transportation research board. Aug 03, 2017 design of slab bridges part ii duration. The example illustrates the design of a typical threespan continuous straight steel i girder bridge with spans of 140. References to aashto standard specifications in this chapter refer to the aashto standards specifications for highway bridges, 16 th edition, 1996, including the 1997 and 1998 interims and. Example on design of slab bridge design data and specifications superstructure consists of 10m slab, 36m box girder and 10m tgirder all simply supported. Bridge design guide 32 txdot january 2020 section 1 general recommendations prestressed concrete beam and girder design txdots policy is held firmly to a 6. Bridge design specifications and commentary and in analysis guidelines for these types of bridges. The deck may consist of 3 girders spaced at 2, 45 m.
Key words i girder, curved bridge, lifting, erection, construction 18. Class 5000 or higher used in cip posttensioned concrete box girder construction, deep bridge foundations, or in other special structural applications if significant economy can be gained or structural requirements. Plate girder worked example 1 made by sssr date 150400 structural steel design project calculation sheet checked by pu date 250400 mc pyf af hs 217. July 2019 276 the required design input for the design of an elastomeric bearing at the service limit state is dead load, live load plus dynamic load allowance, minimum vertical force due to permanent load, and design translation. The centerline of the bridge lies on a 400 ft radius and the crosssection is a two cell box. Bridge design specifications second edition, 1998, including interims for 1999 through 2002. Use is made of a computer program to compare the behaviour of. The design criteria is to strengthen the girder to obtain a hs20 live load rating factor equal to or greater than 1. Design guidelines for steel trapezoidal box girder systems 6. Thus, use of a hybrid girder requires an approved design waiver. The new design aids provide bridge designers with different alternatives of girder section size from nu900 to nu2000, girder spacing from 612ft, number of prestressing strands up to 60, prestressing strand. The behavior of box girder section for a general case of an eccentric load has been s tudied and presented its studies in chapter 2. Bharil, in innovative bridge design handbook, 2016. Comprehensive design example for prestressed concrete girder.
Note that acceptable design methods are not limited to those. Design guidelines for steel trapezoidal box girder systems. The tendon profile considered for the design of post tensioned box girder bridge is parabolic and mathematical model is shown in figure 6. Girder analysis and design is performed using the computer program conspan, version 09.
Department, sri vasavi institute of engineering and technology, andhra pradesh. Analysis and design of prestressed box girder bridge by irc. Example b1 comprehensive problem spine and grillage b5 b. The design example and commentary are intended to serve as a guide to aid bridge design engineers with the implementation of the aashtolrfd bridge design specifications. Compression struts develop because of the presence of stirrups plate girder tension field action develops because of the placement of vertical and horizontal stiffeners. Preliminary design making the correct choice of bridge deck type. Interaction of the various components considers the design and detailing of the rail the girder, the horizontal girder or surge plate and columns and founda tions. For large structures, perform a web depth study to arrive at the optimal girder height.
For this example six decimal places are used for the input. This section contains six typical concrete beam and girder superstructure designs. Structural steel 1 of 18 rev plate girder design project. See aashto 2011, the manual for bridge evaluation, second edition, table 6a. The most efficient depth of girder will vary with span and girder spacing. Stuchndarnubmoxamdqajntmt theoryofetnadjatfibution. Girder bridges are the most natural and simplest form of bridging between two points.
Pgsuper uses a stateoftheart iterative design algorithm and other iterative computational procedures. This example is based on aashto lrfd bridge design specifications, 7th edition. Tech structural engineering, mandava institute of engineering and technology, andhra pradesh s. The load analysis and stress checks include a number of effects which are generally of second order importance in conventional plate girder design such as shear lag, distortion and warping stresses, and stiffened. The guidance in this publication has been developed from earlier wellestablished guidance in a number of sci bridge design guides. Finally, an example of the analysis of a bridge composed of a continuousspan, posttensioned concrete box girder superstructure and a concrete pier is also demonstrated using the approximate equivalent load method. Threespan continuous straight composite i girder load and resistance factor design third edition customary u. The design process and corresponding calculations for steel i girders are the focus of this example.
This manual supplements the aashto lrfd specifications. Wisdot bridge manual chapter 24 steel girder structures. Concrete box girder highway bridges final report january 29, 2008 nrv. Impact of lrfd specifications on design of texas bridges. Click on a datetime to view the file as it appeared at that time. Design of reinforced concrete bridges department of civil. The example illustrates the design of a typical threespan continuous straight steel igirder bridge with spans of 140. The required design input at the strength limit state is shear force. The design rules have now been simplified with the publication of bs5400 and more realistic imperfection limits have been set. This manual is intended to provide general guidance, and not solutions that are specific to any project. Example b5 global plus regional combination poldony b147 f. This document consists of a comprehensive steel girder bridge design example, with instructional commentary based on the aashto lrfd bridge design specifications second edition, 1998, including interims for 1999 through 2002. Texas u54 girder using both the aashto standard specifications and aashto lrfd specifications were also developed and compared. Penndot dm4 design manual follows such a practice others have assigned 60.
Mar 19, 2014 click on a datetime to view the file as it appeared at that time. Bridge design to eurocodes worked examples worked examples presented at the workshop bridge design to eurocodes, vienna, 46 october 2010 support to the implementation, harmonization and further development of the eurocodes y. Note that for the calculation of the fatigue moments and shears that. Tendency of lrfd bridges construction during recent years. Threespan december 2015 continuous horizontally curved composite steel i girder bridge 6.
Design step 5 design of superstructure prestressed. Only the design of slab bridge will be used for illustration. Created a new prestress girder example from the pci bridge design manual example 9. Design of posttensioned girder anchorage zones june 1981 6. Design step 5 design of superstructure prestressed concrete.