Analysis and design of prestressed box girder bridge by irc. Thus, use of a hybrid girder requires an approved design waiver. Department, sri vasavi institute of engineering and technology, andhra pradesh. 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. From girder end midspan of noncomposite beam girder top stress. It gives two worked examples, one for a multi girder bridge and one for a ladder deck bridge. Stuchndarnubmoxamdqajntmt theoryofetnadjatfibution. This manual supplements the aashto lrfd specifications. Pgsuper uses a stateoftheart iterative design algorithm and other iterative computational procedures. The example illustrates the design of a typical threespan continuous straight steel igirder bridge with spans of 140. 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. Aashto lrfd bridge design specifications specific to new mexico bridge design practice so that uniformity in bridge design procedures will be attained. 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. Key words i girder, curved bridge, lifting, erection, construction 18.
Design step 5 design of superstructure prestressed concrete. 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. Girder analysis and design is performed using the computer program conspan, version 09. 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 deck may consist of 3 girders spaced at 2, 45 m. Design of posttensioned girder anchorage zones by w. Threespan continuous straight composite i girder load and resistance factor design third edition customary u.
Threespan december 2015 continuous horizontally curved composite steel i girder bridge 6. Bharil, in innovative bridge design handbook, 2016. Wisdot bridge manual chapter 24 steel girder structures. Wisdot bridge manual chapter 24 steel girder structures july 2019 245 24.
Click on a datetime to view the file as it appeared at that time. Bridge design specifications and commentary and in analysis guidelines for these types of bridges. Design guidelines for steel trapezoidal box girder systems 6. This example is based on aashto lrfd bridge design specifications, 7th edition. Typically a member taller than the minimum will be the most efficient. New bridge design information is continually developing. Within the state of nebraska, the two standard precast prestressed products used are inverted tee it girders and university of nebraska nu igirders. Impact of lrfd specifications on design of texas bridges. Preliminary design making the correct choice of bridge deck type reinforced concrete. We will be using this bridge model as a reference for analysis in staad pro beava which is meant for structural analysis of bridge.
Note that for the calculation of the fatigue moments and shears that. For large structures, perform a web depth study to arrive at the optimal girder height. Design aids of nu igirder bridges nebraska department of. Standard short span steel girder bridge designs goals. Example b5 global plus regional combination poldony b147 f.
The guidance in this publication has been developed from earlier wellestablished guidance in a number of sci bridge design guides. The design rules have now been simplified with the publication of bs5400 and more realistic imperfection limits have been set. 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. This section contains six typical concrete beam and girder superstructure designs. Third edition of the aisc lrfd manual of steel construction. Simple span reinforced concrete tee beam bridge rating example. Bridge design specifications second edition, 1998, including interims for 1999 through 2002. Only the design of slab bridge will be used for illustration. Siteblauvelt engineers cranberry township, pa pittsburgh, pa b s d i design. Plan, elevation and section views are shown on the following pages.
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. The design criteria is to strengthen the girder to obtain a hs20 live load rating factor equal to or greater than 1. 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. 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.
Compression struts develop because of the presence of stirrups plate girder tension field action develops because of the placement of vertical and horizontal stiffeners. The design process and corresponding calculations for steel i girders are the focus of this example. Note that acceptable design methods are not limited to those. Key words igirder, curved bridge, lifting, erection, construction 18. Making the correct choice of deck will depend on many factors. The design example and commentary are intended to serve as a guide to aid bridge design engineers with the implementation.
However, the typical load combination for superstructure design is the group i load combin ation. Use is made of a computer program to compare the behaviour of. Analysis and design of prestressed box girder bridge by. 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.
Example b4 global plus regional combination menn b7 e. 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. Aug 03, 2017 design of slab bridges part ii duration.
Example b1 comprehensive problem spine and grillage b5 b. 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. It is a companion to a publication giving general guidance on composite highway bridge design. Mar 19, 2014 click on a datetime to view the file as it appeared at that time. Tendency of lrfd bridges construction during recent years. 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. Example on design of slab bridge design data and specifications superstructure consists of 10m slab, 36m box girder and 10m tgirder all simply supported. Preliminary design making the correct choice of bridge deck type. Comprehensive design example for prestressed concrete. Locate field splices at or near points of dead load contraflexure. This manual is intended to provide general guidance, and not solutions that are specific to any project. The required design input at the strength limit state is shear force.
Extend bearing stiffeners the full height of the girder. The use of girder as a natural bridging element is abundantly. Two design examples of a simply supported slab bridge and a twospan box girder bridge are also presented. Concrete structures chapter 5 wsdot bridge design manual m 2350. Design of prestressed girder for bridge prestressed girder reinforcement details duration. A twospan continuous composite igirder bridge has two equal spans of 165 and a 42 deck width. Multimedia package for lrfd concrete bridge design rosa p. The centerline of the bridge lies on a 400 ft radius and the crosssection is a two cell box. Chances are very high that today, a bridge engineer will learn how to design a bridge girder before any other bridge type. Design of posttensioned girder anchorage zones june 1981 6. Texas u54 girder using both the aashto standard specifications and aashto lrfd specifications were also developed and compared. Design step 5 design of superstructure prestressed. Design of reinforced concrete bridges department of civil. Girder bridges are the most natural and simplest form of bridging between two points.
For group i, the factored load effects use a factor of 1. Nchrp project number 1271 transportation research board. Structural steel 1 of 18 rev plate girder design project. For this example six decimal places are used for the input.
The example problem is a three span continuous box girder bridge that is 700 ft. The tendon profile considered for the design of post tensioned box girder bridge is parabolic and mathematical model is shown in figure 6. Tech structural engineering, mandava institute of engineering and technology, andhra pradesh s. See aashto 2011, the manual for bridge evaluation, second edition, table 6a. Finally, appendix b presents a worked example of design calculations for a typical half through twotrack railway bridge. 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.
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. Note that for steel tub girders, the provisions of article 6. 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 example illustrates the design of a typical threespan continuous straight steel i girder bridge with spans of 140. Choice of deck bridge design bridge design and assessment. 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. Comprehensive design example for prestressed concrete girder. Steel girder design example using 3rd edition aashto lrfd. Design step 5 design of superstructure prestressed concrete bridge design example task order dtfh6102t63032 549 sample calculations at 54 ft.
The most efficient depth of girder will vary with span and girder spacing. Where round head bolts are required, astm a449 bolts shall be used. A design example followed by a load rating analysis illustrates the engineering computations performed by pgsuper. 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. Several types of truss girders are used in bridge design. Four lrfd design examples of steel highway bridges, vol. Penndot dm4 design manual follows such a practice others have assigned 60. It is assumed the bridge will be cast on falsework.
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