girder bridge design

In ancient Rome, the techniques for building bridges included the driving of wooden poles to serve as the bridge columns and then filling the column space with various construction materials. Design a slab and girder bridge with 7.5 m. clear roadway having a span of 12.0 m. between centre line of bearings. Reaction of the tank load on the cross-beam (assuming simple reaction) =2×35.0x 4.858/6.0= 56.67 tonnes. 6.10 at e.g. Since θ and α values of both the decks are the same, the influence line for transverse moment coefficients as shown in Fig. Therefore, the most economical arrangement of bridge deck varies from place to place depending on the cost of materials, shuttering, staging etc., in that locality. of each load are: The live load moment on the cross-beam of the same deck has been determined for Class AA (tracked) loading. Maximum transverse moment per metre length of the-deck at centre is given by: My = b [µ0r1 – µ30r3 + µ50r5]        (8.3), Where rn = (= 1,3,5) = (4w/nπ) sin (nπu/2a) sin (nπc/2a). Design of T-beam a) Outer girder. The design of steel structures is covered in Section 6 of the AASHTO LRFD Bridge Design Specifications and only straight steel bridges are covered in the provisions as of this writing. Depending on the design requirements and as per the nature of the structure; metal thicknesses for web, flanges, stiffness, etc are determined. The reaction on the outer girder will give the shear on the cross beam. on the inner side. Define and design girder components in an interactive graphical calculation environment. A girder bridge is the most common type in bridge design. of each load are given below: In this case, the Udl is distributed throughout the length but the wt. The live load shear on the central girder is evaluated considering the deck slab con­tinuous over the central girder and partially fixed over the outer girders. Material type, shape, and weight all affect how much weight a beam can hold. The basic configuration of composite box girder highway bridges is normally that of a reinforced concrete deck slab on top of one or more fabricated steel girders. Loading, analysis, design A girder may be made of concrete or steel. A design example followed by a load rating analysis illustrates the engineering computations performed by PGSuper. where normal width of web of 300 is available and where the shear resistance of bent up bars is not effective). A girder bridge is a bridge that uses girders as the means of supporting its deck. A spacing of about 4.5 m. to 6.0 m. is generally found satisfactory. ... DLM on outer girder = 3/8 x 1,81,230 = 67,960 K gm. In such case, the sharing of the shear may be assumed as 0.25 on each outer girders and 0.5 on the central girder. Effective flange width shall be the least of the following: The distribution of dead load of slab, wearing course etc. AASHTO LRFD Bridge Design Specifications, … 25 Φ HYSD bars bent up bars, shear resistance = 2 x 490 x 200 x 0.707 = 1,38,600 N. Balance shear of 1,84,300 N is to be resisted by stirrups. PGSuper uses a state-of-the-art iterative design algorithm and other iterative … As per Clause 304.7 of IRC: 21-1987, permissible shear stresses for M20 concrete, i) Without shear reinforcement = 0.34 MPa, ii) With shear reinforcement = 0.07 x 20 = 1.40 MPa.–. The substructure is the foundation, transfers loads from the superstructure to the ground. Attention Internet Explorer users: In order to download Mathcad files, right click on the link and choose "Save target as." It depends on many factors such as the span-width ratio, properties of the bridge deck and the position of the live loads on the girders. With a stirrup spacing of 175 mm, ...If 10 Φ 4 legged stirrups are used, Asw provided = 4 x 78 = 312 mm 2. Shear resistance of 2 – 28 Φ bent up bars in double system = 2x2x615x200x 0.707 = 3,47,800 N, However, not more than 50 per cent of the shear shall be carried by bent up bars. Span and support moment in the longitudinal direction per metre = 670 x 0.8 x 1.25 = 670 K.gm. = 2,44,000 Nm. The girders for this bridge are designed to meet … Total design moment for central girder = DLM + LLM = 45,300 + 69,190 = 1,14,490 Kgm. Design a slab and girder bridge with 7.5 m. clear roadway having a span of 12.0 m. between centre line of bearings. As the Industrial Revolution came and went, new materials with improved physical properties were utilized; and wrought iron was replaced with steel due to steel's greater strength and larger application potential. In this publication, attention is concentrated upon medium-span highway bridges - those with the longest span in the range 45 m to 100 m. Continuous Span Standards. 2010. i) At mid span, design moment = 31 + 670 = 701 Kgm. The spacing of main girders thus affects the design of the slab as well as the number of girders … //]]>. shear = 1.45 x 35,000/3 = 16,916 Kg. ; Average ac in the flange may be taken as 0.8 x 6.7 = 5.36 MPa, σs = 200 MP.. Average steel stress will be 200 x 1060/1088= 196 MPa, The section of the girder is the same as that of the outer girder but the design moment is less. 6.10 at e.g. Dividing the equivalent width into 4 equal parts, load per part = 6944/4 = 1736 Kg. Shear and Shear Reinforcement near support: Shear taken by outer girder = 3/8 x 9720 x 6.0 = 21,870 Kg. The transverse moment coefficients may be obtained from the influence line curves (Fig. The mechanical device is known as “shear connectors” and in such bridge decks, the depth of the girders is reckoned from the bottom of girders to top of slab, the deck slab acting as a lop flange of the new girders termed as “composite girders”. Beam bridges are generally considered the simplest form of bridge. How simple? = 20,830 Kgm. for the latter. Image Guidelines 5. A box girder is formed when two web plates are joined by a common flange at both the top and the bottom. Due to the properties of the second moment of area, the height of a girder is the most significant factor to affect its load capacity. = 220 + 2872 = 3092 Kgm. L.L. 6.10 will remain the same. when a gap is maintained between the deck slab and the cross­beam, the slab may be designed as one way slab. Shear at a distance of 2.5 m. (i.e. The girders are spaced at 2.5m (c/c girder). The deck slab has to distribute wheel loads to the main girders and also to transfer some load from more highly loaded girders to adjacent ones. = -7200 Nm. In a beam or girder bridge, the beams themselves are the primary support for the deck, and are responsible for transferring the load down to the foundation. The box is typically rectangular or trapezoidal in cross-section. All bridges consist of two main parts: the substructure, and the superstructure. The girder spacing’s in such cases are usually between 2.25 to 2.75 metres. October 9, 2018 - by Arfan - Leave a Comment. Class A wheel load as shown in Fig. Since the span-width ratio of the deck is less than 2, the transverse deck is not rigid and therefore the central cross-beam is designed by Morice and Little’s simplified Method. ... Design L.L.M. You need to start with specifying input parameters to design a specific bridge structure. Both must work together to create a strong, long-lasting bridge. 8.13. The span of the girders is 23.35m(c/c brg), and the overall girder length is 24.0m. For proper functioning, at least two cross-beams at two ends and one at the centre are essential. Design Strategies Provide drip plates (also called drip tabs) to divert runoff water and protect abutments and columns from staining. D.L. ... Design moment = DLM + LLM = 4060 + 20,830 = 24,890 Kgm. Shear due to wt. Dead load shear due to weight of cross beam on outer girder = 1/4 of total shear = ¼ x ½ x 2090 = 260 Kg. However, with the inclusion of a truss or arch the bridge is no longer a true girder bridge. The portion of the load coming on the cross girder after longitudinal distribution will be shared by the main beams in proportion to the distribution coefficients already found out previously. PGSuper is a computer program for the design, analysis, and load rating of precast, prestressed concrete girder bridges. In the example, Class 70-R tracked vehicle will govern the design. PCI has developed Preliminary Design Charts in accordance with the AASHTO. Since the shear stress exceeds the permissible limit of 0.34 MP, without shear reinforcement, the same is necessary. interior girder Wearing Surface Load (DW) - Wearing surface = [0.025 x 40.0]/4 girders = 0.250 k/ft Note: Distributed equally to each girder B S D I Basic LRFD Design Live Load HL-93 - (Article 3.6.1.2.1) Design Truck: Þ or Design Tandem: Pair of 25.0 KIP axles spaced 4.0 FT apart superimposed on Design Lane Load 8.1. 8.11. The section of the outer girder is shown in Fig. NeXT Bridge Beams (104k, PDF) PCI Zone 6 Curved Spliced Girders (1.8mb, PDF) Slab Shapes (183k, PDF) Span by Span (162k, PDF) There are a number of different beam shapes in the U.S. Market. Reinforcement details of central girder are shown in Fig. ii) At support design moment = -62 -670 = -732 Kgm. Hence this stress in within the permissible limit with shear reinforcement. Bridge Design Group. Since in this case the span-width ratio is less than 2, Morice and Little’s simplified method of load distribution will be used. shear on the outer girder = Distribution coefficient x average L.L. [2][3][4][5] However, some authors define beam bridges slightly differently from girder bridges.[6]. Hence, shear to be resisted by bent up bars and stirrups is ½ x 4,56,700 = 2,28,350 N. each. ...Design shear on the cross-beam = D.L. These bridge design excel sheets are designed according the latest codes like ACI, AASHTO LRFD, etc. Plagiarism Prevention 4. Rough sketch of bridge design: When the engineer is sure that a design idea has emerged in his mind, he should pick up a pencil and a scale and by the help of sketching, learned at school, he should start from sketching the probable road direction, beam depth(For beam bridge) the piers, the abutments and the bottom … Hence satisfactory. 22.5.3 Precast single span bridge girder (bridge design model) Two traffic bridge design models having one 45 m single span were analysed (see Almansour and Lounis, 2008).They consist of precast/prestressed girders and a cast-in-place … Another modification is the use of Fig. The box girder normally comprises prestressed concrete, structural steel, or a composite of steel and reinforced concrete. The values of the coefficients m1 and m2 are obtained from the curves when the values of U/B , V/L and K (= B/L Shorter Span/ Longer Span)are known. is shown in Fig. The effective flange width shall be the least of the following: ii) Centre to centre distance of beam, i.e. Bridges,” Chapter 4. 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. The deck may consist of 3 girders spaced at 2, 45 m. centres. 8.16a. ¼ x 9700 x 2.5 = 6075 Kg. Several limitations must be ob- served when using the suggested approach that reflect the range of parameters consid- ered in its development. Girder bridges have existed for millennia in a variety of forms depending on resources available. In truss and arch-style bridges, the girders are still the main support for the deck, but the load is transferred through the truss or arch to the foundation. Since it is a two-way slab, the live load moments will be determined by using Pigeaud’s method with Poisson’s ratio of concrete to be 0.15 as advocated in the. Total D.L. Prohibited Content 3. 8.10). Using 10 ф 2 legged stirrups @ 125 mm., Asw required = Vs/σsd= (1,84,300×125)/(200×922.5) =125 mm2. where W is the total load. B-15 in place of B-14 (Appendix B) for the determination of the values: Moment on the cross-beam with 10 percent impact = 1.1 x 17.22 = 18.94 tm. Shear reinforcement at other sections of the girder shall be worked out on the same principles as outlined above. bars @ 150 mm (As = 375 mm 2). analysis of the slab. A typical bridge girder with a portion of the span, over which the compression flange is laterally unrestrained, is shown in Fig Such a girder is susceptible to lateral torsional buckling. 8.11. + L.L.M. It has been advocated that due to continuity, the mid-span moments may be reduced by 20 percent and the same moment may be taken as the support (negative) moment also. The Third Edition of the design specifications, to be published in 2004, will contain a complete set of new at the centre of the span. Content Guidelines 2. shear = 5556 + 27,390 = 32,946 Kg. = 30,300 Nm. Load per metre of deck excepting wt. The deck under consideration is subjected to Class 70-R loading. Less load on 2.5 m length i.e. Using 2 nos. of each part may be summed up and the transverse moment may be obtained from equation 8.3 assuming u = c = a. 6.10 at beam position are as below: The cross beams may be divided into 4 equal parts the wt. ∑µ values from Fig. In the example, simple thumb of rules are used to start the AASHTO-LRFD design for prestressed precast girders. 1.1 RC DECK OF RC GIRDER BRIDGES The design example comprises of 5.35m wide deck with 2-girder arrangement. Reinforcement for central girder, As = 11,22,000 x103/ 196×1060 = 5400 mm2, Provide 12 Nos. This exceeds the permissible limit of shear stress of 1.40 MP, with shear reinforcement. The study considered several bridge configurations for which detailed finite element analyses were conducted. Both deck and girder concrete shall be of 28 days crushing cylinder strength f‟c = 25 … Deck drains 10/27/15 . Many shorter bridges, especially in rural areas where they may be exposed to water overtopping and corrosion, utilize concrete box girder . Let us assume that outer girders take 3/8th each and central girder ¼ th of the total load. It depends on many factors such as the span-width ratio, properties of the bridge deck and the position of the live loads on the girders. = 3,22,900 N. Shear may also be calculated from the transverse moment on the cross girder found out previously assuming that UDL is acting on the cross-beam and the cross-beam is simply supported on the outer girders. Before publishing your articles on this site, please read the following pages: 1. Shear + L.L. When cavemen laid logs over streams to cross them, they were building the earliest beam bridges.These basic bridges typically span relatively short distances. Learn about the CSiBridge 3D bridge analysis, design and rating program for the design and optimization of steel girder bridges with composite decks. The bridge deck will have no footpaths. The spacing of the girders depends on the number of girders to be provided in the deck which again is related to the cost of materials, shuttering, staging etc. Shear resistance of 2 Nos. This example illustrates the design of a two span cast-in-place post-tensioned concrete box girder bridge. These types of bridges have been built by human beings since ancient times, with the initial design being much simpler than what we enjoy today. Shallow girder depth’s may be used where vertical clearance below the bridge is critical. T Beam Girder Bridge Design. = 15,51,700 Nm. = 2 x ½ x 2.45 x 1.225 x (0.215 x 2400 + 0.085 x 2500) = 2186 Kg. On inspection of the cross-section of the deck it may be noted that dead load sharing on the outer girders will be more. Closer beam spacing means lesser thickness of deck slab and consequently savings in concrete and steel in deck slab but since the number of beams is more in that case, this increases the quantity of concrete, shuttering and reinforcement for girders and for longer spans where bearings are required, the number of bearings. shear on outer girder = 1.1 x 16,916 = 18,600 Kg. 6.10) corresponding to the beam positions, weight of each beam per metre run is equal to 925 Kg. 8.4 will produce worst effect and will therefore, govern the design. on cross girder = 1.1 x 18.94 = 20.83 tm. If no gap between the deck slab and the cross beams is maintained, the slab panel becomes a two-way slab continuous in both the direction. Privacy Policy 8. Therefore, the sharing or distribution of live loads on the girders and consequently the live load moment varies from girder to girder and as such this aspect requires to be considered carefully. Loading – Single lane of Class 70-R or two lanes of Class A: Let the cross-section of the deck be assumed as shown in Fig. Since the deck slab is monolithic with the cross-beams, it will be designed as a two-way slab supported on longitudinal girders and cross-beams with continuity on all sides. Longer spans, more traffic, or wider spacing of the beams will all directly result in a deeper beam. In order to build a beam bridge (also known as a girder bridge), all you need is a rigid horizont… D.L. ...Total dead load shear = 2186 + 595 + 2775 = 5556 Kg. ii) Shear due to self wt. Sometimes in long bridges, it is necessary to keep provision for carrying pipes (gas, oil or water), cables etc., through the bridge deck for which space under the footway may be utilised as shown in Fig. ii) To offer resistance to torsion of main girders. The closed cell which is formed has a much greater torsional stiffness and strength than an open section and this is the main reason why box girder configuration is usually adopted in long span bridges. However, there are three number cross-girder for effective spans up to 16.5 m. and four number cross-girder for effective spans of 18.75 to 24.75 m. The design is based on M20 grade concrete and S 415 grade steel. = 11,22,000 Nm. A box girder bridge, or box section bridge, is a bridge in which the main beams comprise girders in the shape of a hollow box. Loading – Single lane of Class 70-R or two lanes of Class A: The bridges constructed by Romans were at the time basic but very dependable and strong while serving a very important purpose in social life. Wt. For simply supported spans, this limit is generally found to be nearly 10 metres and for continuous or balanced cantilever type structures, this limit is 20 to 25 metres. in place of the slab thickness of 215 mm. Span and support moment in the transverse direction per metre = 2872 x 0.8 x 1.25 = 2872 K.gm. The cross-beams or diaphragms are used in a bridge deck for the following reasons: i) To distribute loads between main girders. Reaction on outer girder = 56.67/3 x 1.45 (distribution co-efficient) = 27.39 tonnes = 27,390 Kgs. Shear = 22,130 + 18,600 = 40,700 Kg. i) Shear due to weight of deck slab and wearing course. The deck slab of a slab and girder bridge spans transversely over the girders which run longitudinally spanning between abutment or pier supports. The Ministry of Shipping and Transport (Roads Wing), Govt. After reading this article you will learn about the design of slab and girder bridges. A bridge crane is a type of overhead crane that includes two or more overhead runways built into the building’s support structure. bridges to curved steel I-girder bridges (Doust 2011). Distribution of Live Load Moments on the Girders: ‘ The live load and consequently the live load moment will be distributed over the girders in varying proportions depending on the properties of the deck. of each part is assumed to act at its centre of gravity. Disclaimer 9. Consider what the diverted water will stain—for example, do not 28 Φ HYSD bars (As = 7380 mm2). T. Stengel, P. Schießl, in Eco-efficient Construction and Building Materials, 2014. of cross beam acting along transverse direction but point load along longitudinal direction. Slab and girder bridges are used when the economical span limit of solid slab bridges is exceeded. 2.1.2.1. Structural Bridge Design bridge analysis software integrates loading, analysis, and code checking (AASHTO LFRD, EURO-CODES, and more) throughout the project. It lets you design different kinds of bridge projects including Box Girder, Spectra, Curved, Prestressed Girder, I-Beams, U-Beams, and many more. a) Udl due to deck slab and wearing course: To find out the transverse moment due to load of item (a) above, the equivalent deck of width 7.35 m. may be divided into a number of equal parts’ say 4 equal pans each of 1.84 m. width and the effect of each load on the transverse deck acting at the e.g. The design example and commentary are intended to serve as a guide to aid bridge design … i) At mid span, design moment = D.L.M. [citation needed], The term "girder" is often used interchangeably with "beam" in reference to bridge design. shear on central girder = 14,580 + 520 = 15,000 Kg. In this way with the help of supervision and available data & sources, we have designed this T -girder bridge. For plate girder bridges with long spans, it is important to balance the strength and service design with the need to meet prescribed live load deflection requirements. Steel Girder Design Mathcad® Sheets . However, since the length of Class 70-R tracked loading is 4.57 m. in place of 3.60 m. for Class AA tracked loading, the loading will be 7.66 tonnes/m. 2,28,350 N. each to offer resistance to torsion of main girders bridge structure users in. ) to offer resistance to torsion of main beams acting along transverse direction but point load along longitudinal direction mm... Total dead load sharing on the cross-beam ( assuming simple reaction ) =2×35.0x 4.858/6.0= 56.67 tonnes bridges Advantages... Long-Lasting bridge the range of parameters consid- ered in its development shown as XML, be sure change... ( 200×922.5 ) girder bridge design mm2 such the total load for proper functioning, least. 1.1 x 56,670 = 62,340 Kgs were building the earliest beam bridges.These bridges. Basic but very dependable and strong while serving a very important purpose social..., structural steel, or wider spacing of knee braces to 12 feet maximum the other hand, not! File extension is shown as XML, be sure to change it to XMCD forms depending on available... Design girder components in an overhang 125 mm., Asw required = (... Are intended to serve as a guide to aid bridge design Manual shall be least. For live load within 5.5 m. of either supports will be close to each other than bridges with deep.... Part may be used where vertical clearance below the bridge decks have three number T-beams of varying depths depending spans... ( c/c girder ) beam acting along transverse direction per metre = 670 x x... Reaction ) =2×35.0x 4.858/6.0= 56.67 tonnes live loads, on the outer =... Under consideration is subjected to Class 70-R tracked vehicle will produce maximum (... N. shear stress = v/bd = 3,99,200/300×1060 =1.26 MP summed up and the superstructure prestressed concrete, steel!: shear taken by central girder = ¼ x 9720 x 6.0 = +! 56.67/3 x 1.45 ( distribution co-efficient ) = 2186 Kg: ii ) at mid and! ( as = 375 mm 2 ) overtopping and corrosion, utilize concrete box normally... Slab thickness oldest girder bridge design of modern steel girder bridges the design of bridges are given in Table 8.1 and.., more traffic, or a composite girder bridges 3.1 girder spacing ’ s such! Girder per m. = 1/3 x 2776 Kg by outer girder is shown in Fig by. On resources available type of overhead crane that includes two or more overhead runways built into the building’s structure! By Romans were at the centre are essential normal width of web of is! Following dead loads: a ) Udl due to wt and Transport Roads... Longitudinally spanning between abutment or pier supports type of overhead crane that includes two or more overhead built..., prestressed concrete, structural steel, or wider spacing of the deck consist... When a gap is maintained between the deck may consist of 3 girders spaced at,... Strong, long-lasting bridge ends and one at the centre are essential mm.... In reference to bridge design x average L.L bridge width run longitudinally between... Gap is maintained between the deck thereby resulting in an overhang ) =125 mm2, Class 70-R loading load. Is available and where the shear stress of 1.40 MP, with the inclusion of a two span cast-in-place concrete. With the AASHTO substructure, and the overall girder length is 24.0m 0.07... Percent of the live load moment on the cross-beam ( assuming simple reaction ) =2×35.0x 4.858/6.0= 56.67.. Used to refer to a steel beam which run longitudinally spanning between abutment or pier supports to start the design. Represent an excellent starting point for 3-span Continuous steel plate girder design at its centre of gravity precast. Shear stress = v/bd = 3,99,200/300×1060 =1.26 MP since θ and α values of both the faces shall the! Internet Explorer users: in order to download Mathcad files, right click on the same is necessary total load... An excellent starting point for 3-span Continuous steel plate girder design to the following:... Effect and will therefore, the sharing of the girders which run longitudinally spanning abutment! These bridges are plate and box the design of bridges are given below: the is... Design … analysis of the above as stated before and allowing for 25 percent following: the beams! Girder components in an overhang m. ( i.e longer a true girder bridge transverse deck at position. Serve as a guide to aid bridge design … analysis of the loads... About 4.5 m. to 6.0 m. is generally found satisfactory sources, we have this... And as such the total L.L loads, on the other hand, is not effective ) the transverse per. Design for prestressed precast girders load moment on the transverse direction per metre run is to. Reference to bridge design … analysis of the following pages: 1 = 1.1 56,670... Served when using the suggested approach that reflect the range of parameters consid- ered in its development up and overall! Feet maximum = 45,300 K gm available and where the shear on outer girder 21,870... = 1/4 x 1,81,230 = 45,300 K gm pages: 1... design for... Clear roadway having a span of the following reasons: i ) shear due the... Inspection of the following pages: 1 since the shear resistance of bent up bars is not a simple.. Reflect the range of parameters consid- ered in its development reinforcement on both the shall! Together to create a strong, long-lasting bridge 2186 Kg grade concrete = 0.07 x 20 = 1.40.. 1,81,230 = 45,300 K gm 196×1060 = 5400 mm2, Provide 12 Nos shows a laterally buckled of. Parts: the substructure is the foundation, transfers loads from the influence for! Extending past the fascia girders, thereby resulting in an overhang other than bridges with deep girders as well two!, the term `` girder '' is typically rectangular or trapezoidal in cross-section pgsuper., bridges, especially in rural areas where they may be designed one... Consulted for deck drain policy requirements a specific bridge structure and as such the total load superstructure the. By Arfan - Leave a Comment Violation, solid slab bridges: Advantages, Disadvantages and principles curved! Bridges to curved steel I-girder bridges ( Doust 2011 ) 4 equal parts the wt reinforcement metre! 2872 = -3311 Kgm the girders are typically uniformly spaced transversely with inclusion... ] > limits the spacing of about 4.5 m. to 6.0 m. generally... Mm ( as = 11,22,000 x103/ 196×1060 = 5400 mm2, Provide 12.... A slab and girder bridge = 0.1/100 x 300 x 1000 = 300 mm2 the sharing the. Overall girder length is 24.0m be sure to change it to XMCD m. clear roadway having a of. Bridges to curved steel I-girder bridges ( Doust 2011 ) its centre of.! Were … T beam girder bridge spans transversely over the girders are spaced at,! Sections of the web as in Fig required = Vs/σsd= ( 1,84,300×125 ) / ( 200×922.5 =125. 0.1 percent of the following pages: 1 centre are essential before = 6944.! Learn about the design of a slab and wearing course spread throughout the length but wt... Span and support moment in the example, Class 70-R tracked vehicle will produce worst effect and therefore! Articles on this site, please read the following: ii ) at mid span design! Areas where they may be used where vertical clearance below the bridge has spans of … bridges to curved I-girder!, design moment = DLM + LLM = 4060 + 20,830 = 24,890.... Engineering, Designing, Highway, bridges, especially in rural areas where they may be used vertical... Length but the wt 28 Φ HYSD bars ( as = 11,22,000 x103/ 196×1060 = 5400,... Are the beam to increase beyond what is practical section will be maximum 24,890.... These designs allow bridges to span larger distances without requiring the depth of overhang. = 5556 Kg three number T-beams of varying depths depending upon spans drip girder bridge design ) to distribute loads main. Concrete or steel used in a variety of forms depending on resources available 70-R loading on outer. 1.25 = 670 x 0.8 x 1.25 = 670 K.gm is maintained between the deck it may be obtained equation! Of central girder ¼ th of the web as in Fig girder bridge design state method of design used. Two span cast-in-place post-tensioned concrete box girder normally comprises prestressed concrete girder bridges the cross-section of beams... = 1736 Kg maximum shear when the economical span limit of solid slab is! With the deck as shown in Fig of solid slab bridges: Advantages, Disadvantages and.! Acts on the outer girder is shown in Fig to start with input! For live load moment on the outer girders will be more with 10 per cent impact = x! Deeper beam = ¼ x 9720 x 6.0 = 14,580 Kg principles as outlined above abutments columns. Of shear stress = v/bd = 3,99,200/300×1060 =1.26 MP AREMA Manual limits the of... May be increased by 10 percent 2.45 x 1.225 x ( 0.215 2400! Affect how much weight a beam can hold girder design 18,600 Kg load, this moment may be obtained the! Is often used interchangeably with `` beam '' in reference to bridge design … analysis of the shear on girder! Be assumed as 0.25 on each outer girders and 0.5 on the deck =.... Or a composite of steel and reinforced concrete a true girder bridge x 20 = 1.40 MPa be designed one... Save target as. [ citation needed ], the girder spacing and deck and... `` beam '' in reference to bridge design Specifications, … this example illustrates the,.

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