Basic Structural Engineering By Krishna Raju

Analysis and design of prestressed concrete box girder bridge. By. Miss. P. R. Bhivgade. Recent studies have reported associations between particulate air pollution and daily mortality rates. Populationbased, crosssectional studies of metropolitan areas. Basic Structural Engineering By Krishna Raju' title='Basic Structural Engineering By Krishna Raju' />Abstract Bridge construction today has achieved a worldwide level of importance. Bridges are the key elements in any road network Use of box girder is gaining popularity in bridge engineering fraternity because of its better stability, serviceability, economy, aesthetic appearance and structural efficiency. The structural behavior of box girder is complicated, which is difficult to analyze in its actual conditions by conventional methods. In present study a two lane simply supported Box Girder Bridge made up of prestressed concrete which is analysis for moving loads as per Indian Road Congress IRC 6 recommendations, Prestressed Code IS 1. IRC 1. 8 specifications. The analyzed of box girder using SAP 2. Bridge Wizard and prestressed with parabolic tendons in which utilize full section. The various span depth ratio considered to get the proportioning depth at which stresses criteria and deflection criteria get satisfied. Keywords Concrete Box Girder Bridge, Prestress Force, Eccentricity, Prestress Losses, Reinforcement, Flexure strength, shear strength, SAP Model. I. INTRODUCTIONPrestress concrete is ideally suited for the construction of medium and long span bridges. Ever since the development of prestressed concrete by Freyssinet in the early 1. One of the most commonly used forms of superstructure in concrete bridges is precast girders with cast in situ slab. Basic Structural Engineering By Krishna Raju' title='Basic Structural Engineering By Krishna Raju' />This type of superstructure is generally used for spans between 2. T or I girder bridges are the most common example under this category and are very popular because of their simple geometry, low fabrication cost, easy erection or casting and smaller dead loads. In this paper study the India Road Loading considered for design of bridges, also factor which are important to decide the preliminary sizes of concrete box girders. Also considered the IRC 1. Prestressed Concrete Road Bridges and Code of Practice for Prestressed Concrete Indian Standard. Analyze the Concrete Box Girder Road Bridges for various spans, various depth and check the proportioning depth. Advertisements. II. FORMULATIONA. Loading on Box Girder Bridge The various type of loads, forces and stresses to be considered in the analysis and design of the various components of the bridge are given in IRC 6 2. Section II. But the common forces are considered to design the model are as follows Dead LoadDL The dead load carried by the girder or the member consists of its own weight and the portions of the weight of the superstructure and any fixed loads supported by the member. The dead load can be estimated fairly accurately during design and can be controlled during construction and service. Superimposed Dead Load SIDL The weight of superimposed dead load includes footpaths, earth fills, wearing course, stay in place forms, ballast, water proofing, signs, architectural ornamentation, pipes, conduits, cables and any other immovable appurtenances installed on the structure. Live LoadLL Live loads are those caused by vehicles which pass over the bridge and are transient in nature. QrnPAhP_U/UQla-CAiC6I/AAAAAAAAAN0/gOMYjeekiO4/s1600/pngtrans.png' alt='Basic Structural Engineering By Krishna Raju' title='Basic Structural Engineering By Krishna Raju' />These loads cannot be estimated precisely, and the designer has very little control over them once the bridge is opened to traffic. However, hypothetical loadings which are reasonably realistic need to be evolved and specified to serve as design criteria. There are four types of standard loadings for which road bridges are designed. IRC Class 7. 0R loadingii. IRC Class AA loadingiii. IRC Class A loadingiv. IRC Class B loading. The model is design by considering IRC Class A loading, which is normally adopted on all roads on which permanent bridges and culverts are constructed. Total load is 5. 54, the Fig. Class A. Other information regarding Live load combination as per IRC 6 2. International Journal of Engineering Research and Applications IJERA is an open access online peer reviewed international journal that publishes research. Clause No. 2. 07. Note No. 4. B. Thickness of Web. The thickness of the web shall not be less than d3. C. Thickness of Bottom Flange. The thickness of the bottom flange of box girder shall be not less than 12. D. Thickness of Top Flange. The minimum thickness of the deck slab including that at cantilever tips be 2. For top and bottom flange having prestressing cables, the thickness of such flange shall not be less than 1. E. Losses in Prestress. While assessing the stresses in concrete and steel during tensioning operations and later in service, due regard shall be paid to all losses and variations in stress resulting from creep of concrete, shrinkage of concrete, relaxation of steel, the shortening elastic deformation of concrete at transfer, and friction and slip of anchorage. In computing the losses in prestress when untensioned reinforcement is present, the effect of the tensile stresses developed by the untensioned reinforcement due to shrinkage and creep shall be considered. Advertisements. F. Calculation of Ultimate Strength. Ultimate moment resistance of sections, under these two alternative conditions of failure shall be calculated by the following formulae and the smaller of the two values shall be taken as the ultimate moment of resistance for design i. Failure by yield of steel under reinforced sectionMult 0. As. Fp. Where,As the area of high tensile steel. Modio 4 Full Version. Fp the ultimate tensile strength for steel without definite yield point or yield stress or stress at 4 per centelongation whichever is higher for steel with a definite yield point. Failure by crushing concrete. Mult 0. 1. 76 bdb. Basic Structural Engineering By Krishna Raju' title='Basic Structural Engineering By Krishna Raju' />Where,b the width of rectangular section or web of beamfck characteristics strength of concrete. G. Calculation of Section un cracked in flexureb width in the case of rectangular member and width of the rib in the case of T, I and L beamsd overall depth of the memberfcp compressive stress at centroidal axis due to prestress taken as positive. III. ANALYSIS AND DESIGN OF POST TENSIONED DECK TYPE BOX GIRDER BRIDGEA post tensioned deck type Box Girder. Bridges of clear span 3. Assume Live Load as per IRC 6 2. The Bridge analysis for different Ld ratio starting from 1. Ld ratio considered are as follows Case 1 Ld 1. Case 2 Ld 1. 8, d 1. Case. 3 Ld 1. 7, d 1. Case. 4 Ld 1. 6, d 1. Case. 5 Ld 1. 5, d2. Preliminary data. Iit Pave Software. Clear span 3. 0m. Width of roadway 7. Overhang from face of girder 1. Deck thickness 0. Bottom slab thickness 0. Girder thickness 0. The tendon profile is considered as parabolic in nature. As per IRC 1. 8 2. Mpa, fci 0. 8fck 4. Mpa,fct 0. 5fci 2. Mpa, fcw 0. 3. 3fck 1. Mpa ft 11. 0fct 2. Mpa, ftw 0. As per IS 1. Ec 5. 70. 0fck. Nm. Mpa, n 0. 8. 5, E 21. Mpa. Validation of Resuts. The bending moment, shear force and deflection result obtained by SAP 2. The bending moment and shear force are calculated by considering different loading condition such as dead load, live load and superimposed load. Same as deflection calculated. This results are the Case 1. Table. 1 Deflection. Load Case. DL SIDLLive Load. Prestressing Force. Deflection at midspan3. Table. 2 Bending Momentt. Span m0. 0. L0. L0. L0. 3. L0. L0. 5. LDL0. 0. 03. LL0. SIDL0. 0. 05. 3. 4. Total. 0. 0. 06. 25. Table. 3 Shear Force tSpan m0. L0. 1. L0. 2. L0. L0. 4. L0. 5. LDL1. LL3. 2. 9. 22. 3. SIDL1. 9. 8. 01. 5. Total. 18. 3. 6. 14. Table. 4 Calculation of Prestress Force. Table. 5 Calculation of Eccentricity. Eccentricity mmPrestressing Force k. NThe eccentricity which give minimum prestressing force e 7. Table. 6 Calculation of Prestress Losses.