Problem Statement Evaluate a six-span cast-in-place reinforced concrete highway overcrossing located in southern California for seismic retrofitting. There is a correction formula (equation 25 in clause 5.8.8.2) which allows for the stiffening effect of concrete in the tension zone. Let: The box girder normally comprises either prestressed concrete, structural steel, or a composite of steel and reinforced concrete. VRd,c = [0.12 1.59 (100 0.011 40)1/3] 1000 574 10-3 = 387 kN ( < 414 kN Fail : see below) Maximum VEd due to gr5 = (Q1Qk1) = 1.35 {50.3 [0.25 + (10.8 + 9.6 + 8.4 + 7.2 + 6) / 12] + 5.5 1.0 0.5 / 12} = 255 kN, Maximum VEd from variable actions is from traffic group gr5 = 255 kN 500X2 + 52115X - 30106 = 0 Moment due to long-term actions = Mqp = 360 kNm Design of T-beam a) Outer girder. Use C32/40 concrete to BS 8500. For decks with skew less than 25 a simple unit The maximum moment of resistance is obtained when x = 0.5d so substituting for x we get: INA = 6434 (574 - 175)2 + 33.4 1000 1753 / (3 200) = 1.32 109 mm4 (steel units) than 25 then a grillage or finite element method of analysis will Second Moment of Area = 1000 6503 / 12 = 22.9 109 mm4 Cracked second moment of area = As(d-dc)2 + Ec,effbdc3 / 3Es Computer analysis will produce Ixx = 10002003 / 3 + 8.356434(574-200)2 = 10.18109 mm4>, Max compressive bending stress in concrete = 759106 200 / 10.18109 = 14.9 N/mm2 Learn faster and smarter from top experts, Download to take your learnings offline and on the go. The design formulae are also based on a maximum depth of concrete in compression of 0.5d; this ensures a strain 0.0035 in the tension reinforcement. Combination 1 SLS Design Moment = 842 kNm (345DL + 497LL) The resistance of concrete in tension is ignored. The relationship between the stress and strain in the reinforcement is as shown in Figure 2 of the code with , The relationship between the stress and strain in the concrete is as shown in Figure 1 of the code with . Checking of the box-girder section under bending at support P1. VEd = shear force due to ultimate actions. The design rules for shear in beams are based on the results of tests carried out on beams with and without shear reinforcement. Mathematical Modeling The mathematical model of a box girder bridge having a span of 30 m is shown in Figure6.2 Fig6.2. Hence dc = [-AsEs + {(AsEs)2 + 2bAsEsEc,effd}0.5] / bEc,eff For values of x > 0.5d the use of the design stress of 0.87fy in tension is invalid, the design becomes inefficient and the failure less ductile. Exposure Class XD1 used for bridge deck soffits. Nominal cover to reinforcement in deck soffit = 60mm, d = 650 - 60 -32/2 = 574 That fact justifies the suggestion made by the Commission Ill of the {ABSE that a comprehensive survey be wittan concerning this particular bridge type. Standard ADOT 42-inch F-shape barriers will be used resulting in a bridge configuration of 1'-7" barrier, 12'-0" outside shoulder, Apply temperature differences given in BS 5400 Pt2 Fig.9 (Group 4) to a 1m wide deck section. For the doubly reinforced rectangular section: Taking moments about the centre of tension for the compressive forces Deck Girder Bridges. Reinforced Concrete Deck Design to EN 1992-2 & UK National Annex. The most common type is the slab deck used for short span bridges. Clause 5.2.3(3) makes an allowance of up to 55% additional weight. Now let us discuss the Five major parts of a Reinforced Concrete Bridge 1.Beam/Girder 2.Bearing 3.Pier Cap/ Headstock 4.Pier 5.Pile cap and Piles. Cl. (Ref:"Concrete bridge engineering:performance and advances" by R.J.Cope). Nominal cover for C32/40 concrete = 45 + c = 60mm with maximum water-cement ratio = 0.55 and minimum cement content of 320 kg/m3, Loading per metre width of deck (unit strip). Total tensile stress in reinforcement = 232.8 + 3.8 = 237 N/mm2, Allowable tensile stress = 0.75fy = 375 N/mm2 > 237 OK. = 1 - [0.5 0.00352 - 0.0022 / {(2 + 1) (2 + 2)}] / [0.00352 - 0.0035 0.002 / (2 + 1)] = 0.416 - 0.4 103 [130 ( 1.8 260 + 2.5 282 - 1.5 260 - 1.9 282 ) + 163 ( 0.9 141 - 0.75 141 )] 10-6 = -14.3kNm. Prestressed Precast Concrete Beam Bridge Design. structure to withstand winds of 286 kilometres per hour (178 mph), earthquakes measuring to 8.5. on the Richter scale, and harsh sea currents. EN 1992-1-1 Table 4.1 gives the Exposure Class XD1 as suitable for deck soffits. Shear stress = V / bd = 388103 / (1000 574) = 0.68 N/mm2 Mult = 14.7 1000 190.6 (574 - 0.416 190.6) 10-6 = 1386 kNm > 1340 OK. Note: Intermediate sections between mid span and the ends of the deck will have a smaller moment than at mid span and a small shear than at the ends of the deck. Limiting concrete stress = 0.6 32 = 19.2 N/mm2 < 23.6 Fail The live load reaction is applied to the deck at the pier location. X = 200 mm, Second Moment of Area of cracked section: Hence Mult = favbXz = favbX(d - X) The beam may fail by crushing of the compression struts regardless of the amount of shear reinforcement. Moment M about centroid of section to restrain Taking first moments of area about the neutral axis: together with a nominal HA live load udl of 17.5 kN/m2 and knife edge load of 33kN/m . ii) Long term after all the creep has taken place. (g) Shear design. Nominal cover to reinforcement in deck soffit = 60mm, Using parabolic-rectangular diagram: 1000 X2 / 2 = 6.45 6434 (574 - X) The width of shear cracks is controlled by ultimate strength calculations. as follows, Bridge Components 11.1 Steel Girder Bridge (PDF) 11.1 Attachment 11A Steel Girder Bridge Detailing Examples (PDF) 11.2. Note: Sign convention is compressive stresses are positive. hc,eff = 158 mm Moment at leading axle = 5.5 (6 6.3 - 6.32/2) + 100 5.7 (6.3 + 5.1) / 12 = 640 kNm, Design SLS moment characteristic combination = Qk1 = 640 kNm, Design ULS moment = Q1Qk1 = 1.35 640 = 864 kNm. span Exterior Interior Exterior Interior X-sectional (kN/m) 31.85 30.98 37.22 34.94 REINFORCED CONCRETE COULMN PIER DESIGN FOR FOUR GIRDER SUPERSTRUCTURE Bearing Capacity(s)= kg/cm 2 Allowable Bearing Capacity (1.25* s)= kg/cm 2 RIGHT BOX GIRDER SUPSTR. . The steel stresses are the maximum values provided by the stress-strain curves, where 0.72fy is a simplification of the expression for steel in compresssion. s = c(d - dc) / dc Section Properties of Composite Bridge Beams to BS 5400 Pt.3:2000 & Pt.5:2005. Modular Ratio m = Es / Ecm = 200 / 33.4 = 6.0, Let dc = depth to neutral axis then equating strains for cracked section: Wood and Armer have developed equations Equating forces: use 12 10-6 per C Crack width wk = sr,max(sm - cm) = 338 0.328 10-3 = 0.11 mm, Recommended value of wmax = 0.3 mm > 0.11 mm OK, Hence B32 bars at 125 centres are adequate for the mid span. 1 m (3.3 ft). Nominal cover cnom = 45 + 15 = 60mm, Design for a 1 metre width of deck (unit strip) HA = 17.5 1.0 + 33.0 = 17.5 kN/m(udl) + 33kN(kel), 30 units HB = 30 10 / 4 per wheel = 75 kN per wheel. In all cases, the appropriate multiple presence factor is applied. 500X2 + 53724X - 30.84106 Worked Example | Design of RC beams for Torsion (EN 1992-1:2004) By. fcd = ccfck/c Check stresses in the concrete and reinforcement at: Reinforced concrete (RC) beams are subjected to torsion when . Essentials slide in bridge construction a guide for bridge designers, Composite construction in Bridge Deck systems by Suhas Khedkar Kishore Saxena, Basic components and parts of bridge structures, Reinforced slab bridge design(AASHTO allowable stress design method), Construction Of A Viaduct/Bridge: An Overview, Influence line diagram for model arch bridge, Irresistible content for immovable prospects, How To Build Amazing Products Through Customer Feedback. Taking moments about the centre of tension for the compressive force Depth to notional surface where nominal cover cnom is provided = a' For skews greater CIRIA Report C660 ("Early-age thermal crack control in concrete") suggests that a value of 10 10-6 per C is unsuitable for some of the concrete aggregates used in the UK and suggest a value of 12 10-6 per C should be used if the type of aggregate has not been specified. Concrete elements discussed include bridge decks, pier caps, reinforced concrete box girders, post-tensioned box girders, pretensioned girders and spliced girders. Maximum HA V = 1.1 190 kN = 209 kN, Maximum HB V = f3 1.3 75 (11.426 + 9.626 + 3.626 + 1.826) / 12 Average stress fav = fcd[1-c2 / {cu2(n+1)}] = 18.1 [1 - 0.002 / {0.0035 (2 + 1)}] = 14.7 N/mm2. be required. Re-working the example gives: 5. Determine depth 'X' to neutral axis of cracked section: Youngs Modulus for concrete for long term loading = Ec/2 = 15.5 kN/mm2 The modified value of Ec used for the crack width calculation is an intermediate value between the short and long term values (clause 4.3.2.1(b)). Use clause 5.3.2 for the resistance moments in slabs. Ultimate Limit State ensures that the structure will not collapse. Depth to neutral axis X = fykAs / (favbs) Activate your 30 day free trialto continue reading. curvature due to temperature strain : be less than 49% of the deck sectional area. maximum water-cement ratio = 0.55 and minimum cement content of 320 kg/m3 sr,max = (3.4 60) + (0.8 0.5 0.425 32) / 0.0407 = 204 + 134 = 338, (sm - cm) = [s - {ktfct,eff(1 + ep,eff) /p,eff}] / Es 0.6s / Es Only the crack widths caused by bending and tension need to be calculated and clause 5.8.8.2 is used. z = [1 - ({1.1 500 6434}/{40 1000 574})]d = 0.85d < 0.95 d z = 0.85 574 = 488mm. reinforcement at 125mm centres: Can be unstable against earthquakes. Only one axle should be considered for reduced load effect (see PD 6687-2:2008 Cl. (b) Estimation of design load and actions. Ixx = 10001773 / 3 + 6.456434(574-177)2 = 8.39109 mm4, Max compressive stress in concrete = 842106 177 / 8.39109 = 17.8 N/mm2, Allowable compressive stress = 0.5fcu = 20 N/mm2 > 17.8 OK. Case 2) When creep and shrinkage in the bridge are substantially complete: Youngs Modulus for concrete for long term loading = Ec/2 = 15.5 kN/mm2 New innovation for model,analysis and design of bridge.You can download midas Civil trial version and study with it: https://hubs.ly/H0FQ60F0 AWARDS 1994 Design Award Winner, Concrete Reinforcing Steel Institute 1994 Engineering Excellence Grand Award, American Consulting Engineers Council 1994 George S. Richardson Medal, 11th Annual International Bridge Conference 1994 Charles S. Whitney Medal, American Concrete . Rigid-Frame Concrete Bridges. Loads due to structures, vehicles, passengers, and etc. The authors proceed from the assumption, however, that its contents . Hence Modified Ec for (345DL + 414LL) = (345 15.5 + 414 31) / 759 = 23.95 kN/mm2, Youngs Modulus for steel reinforcement = Es = 200 kN/mm2 Voided slab and beam and slab bridges are used for larger, single or multi-span bridges. However, the design of the Nevers . are transferred to the substructure through the girder and then to the ground. Each bridge is formed by steel girders acting compositely with a reinforced concrete deck slab. values for Mx, My and Mxy where Mxy represents the twisting moment in k = 1 + (200 / 574)0.5 = 1.59 < 2.0 6.9 spans 21.6 m and supports a superimposed dead load G of 6 kN/m and a live load Q of 20 kN/m (excluding self-weight). Assuming steel yields then: Supporting Structures: k3 = 3.4 (recommended value) 7.2.2) 2) The deck is simply supported and allowed to expand and contract freely. Note: The loading has been simplified to demonstrate the method of designing the slab (See BS EN 1991-1-1 to 1991-1-7, 1991-2 and National Annex for full design loading.). Beam and Slab. Interpolating values of T from EN 1991-1-5 Table B.3 for a 0.65m depth of slab with 100mm surfacing we get: Section Properties Design of bearings, p iers an d abutments are discussed in . Bridge Concrete Girder Prestressed Concrete Girder Design for Bridge Structure Based on AASHTO 17th Edition & ACI 318-11 Bridge Concrete Column Bridge Column Design Based on AASHTO 17th & ACI 318-11 Combination 3 SLS Design Moment = 759 kNm (345DL + 414LL) For the singly reinforced rectangular section: Taking moments about the centre of compression for the tensile force Chapter 7: Box Girder Bridges 281 Fig. These two equations are based on a value of d'/d 0.2, which ensures a strain 0.0035 x 0.6 = 0.0021 in the compression reinforcement. Refer to Design Step 1 for introductory information about this design example. X = 500 6434 / (14.7 1000 1.15) = 190.6mm Limiting stress = 0.6 40 = 24 N/mm2 > 23.9 OK, ii) After all creep has taken place the cracked section properties will be based on the long-term and short-term modulus for the various actions. vc = (0.27 / 1.25) [100 6434 / (1000 574)]1/3 (40)1/3 = 0.77 N/mm2 Region (iii) fails when a flexural crack develops into a shear crack. s = fyk = 500 N/mm2 i) Consider a section at d (a = 0.574m) from the support : in the direction of the principal moments. By calculation of the bending stiffness of a composite bridge girder the tension stiffening is taken into account within the length of the concrete plate cracked. 11. Restructured and provided additional details in Section 6.10 to cover various forms of prestressed concrete box girders based on construction methods. way of reinforcing the slab would be to place the reinforcing steel From Superstructure CLN exterior girder interior girder LEFT GIRDER SUPSTR. from linear strain relationship: sv = 0.97 0.77 = 0.75 N/mm2 > 0.68 OK, Check that the maximum allowable shear stress is not exceeded: A box girder is formed when two web plates are joined by a common flange at both the top and the bottom. concrete as art. Maximum allowable shear force = 0.5bwdfcd The results from the beams tested without shear reinforcement showed that for a constant concrete strength and longitudinal steel percentage, the relationship between the ratio of the bending moment at collapse (Mc) to the calculated ultimate flexural moment (Mu) and the ratio of shear span (av) to effective depth (d) is as shown below: The diagram has four distinct regions, each of which has a different mode of failure. The detailed procedure for the . it is the load bearing member which supports the deck. This paper presents the details and results of a numerical study conducted on posttensioned concrete box girder bridges under close-in detonations. The deck should also be designed to carry the SV80 model vehicle. Activate your 30 day free trialto unlock unlimited reading. reinforced bridges concrete. Use C32/40 concrete to BS 8500. Any other use is at the sole discretion of the user. design of bridge su perstructures, such as slab bridges, box culverts, tee beam bridges, box girders and p restressed concrete bridges. (e) Flexural design (bending moment resistance) (f) Curtailment and anchorage. These bridge design excel sheets are designed according the latest codes like ACI, AASHTO LRFD, etc. Steel stress s = M / zs + 0.6 (differential temperature effects) The Design Crack Width can now be calculated using equation 24 in clause 5.8.8.2. VRd,c = 387 kN 395 kN (2% error say OK for conservative nature of unit strip analysis). 0.372 103 [ 150 ( 3.0 + 5.05 ) + (195 1.5) + (195 1.05)] 10-3 = 634.2 kN, Taking moments about centroid of section to determine required moment M to restrain Effective modulus Ec,eff = (Mqp + Mst)Ecm / {Mst + (1 + )Mqp}, Relative humidity of the ambient environment = 80% (outside conditions) Comprehensive Design Example for Prestressed Concrete (PSC) Girder Superstructure Bridge Design Step 5 Design of Superstructure Design Step 5.6 - Flexure Design Design Step 5.6.1 - Flexural stress at transfer Design Step 5.6.1.1 - Stress limits at transfer . Lever arm z = (d - 0.5x) so substuting for x we get: Additional information is . 6.1Cross Section of Box-Girder 6.1. Maximum VEd due to permanent actions = (GjGkj) VEd = [(1.35 16.3) + (1.2 3.7)] 12 / 2 = 159 kN, Reduction factor for tandem axle at support = av / 2d = 0.5d / 2d = 0.25 The deck carries a 100mm depth of surfacing, A bomb explosion within or near the bridge deck may cause catastrophic damage to the bridge components. DAF for 130kN axle = 1.16 axle load = 1.16130/3 = 50.3kN. a) Heating temperature difference You can download midas Civil trial version and study with it: https://hubs.ly/H0FQ60F0 Presentation Slides: http://www.mediafire.com/view/6j6usc6fxxdkohi/Mid. The permanent load portion of the moment (Mg) has an Ec value equal to half the short term value. decks are most useful for small, single or multi-span bridges and are Design a simply supported reinforced concrete deck slab using a unit strip method. Area = 1000 650 = 0.65 106 mm2 1 Lyang, J., Lee, D., kung, J. As a result, they should be designed properly in order to be able to support possible earthquake forces in the construction of bridge design. You can read the details below. m = 1 - [-0.00012] but not greater than 1 Hence no stiffening effect For bridges with short spans the precast sections are normally voided rectangular, channel, or shape. Design of Deck 5. Equating forces: Ecm = 35.2 kN/mm2 m = 5.7 dc = 171 mm INA = 1.34 109 mm4 c = 22.4 + 1.5 = 23.9 N/mm2 Concrete stress c = M / zc + 0.6 (differential temperature effects) bars at 125 c/c : d = 574mm, Maximum HA V = f3 1.5 (12 17.5 / 2 + 33 11.426 / 12 - 17.5 0.574) The deck should also be designed to Max compressive stress due to positive temperature difference = fL 2.31 = 0.8 2.31 = 1.8 N/mm2 = 5.5 kN/m(udl) + 2 (300kN/3m) axles @ 1.2m centres. BDD Chapter 11: Steel Girder Bridge (PDF) 11.1 . M = (0.4fcu)bxz = (0.4fcu)bx(d - 0.5x) VRd,c = [CRd,ck(1001fck)1/3]bwd Force F to restrain temperature strain : In the case of T Girder and deck slab type, the slab span in two directions since it is cast integrally with main girder and . Topic: Concrete-box superstructure . Cracks due to thermal movements are controlled by providing minimum nominal steel area and restricting the maximum bar spacing. Moment M about centroid of section to restrain 5.4.6 - Coefficient of thermal expansion = 12 10-6 per C. Slab Bridges: Continuous Spans. Mc/bd2 = vc av/d. This bridge design excel sheet contains 11 individual excel sheets which are supported with the most recent codes like ACI, AASHTO LRFD, and so on. Slab Bridges: Simple Spans. Design AI and Machine Learning Demystified by Carol Smith at Midwest UX 2017, Pew Research Center's Internet & American Life Project, Harry Surden - Artificial Intelligence and Law Overview, 13_11_2021+Hydrogen+_++Term+I+Preparation+_+Maha+Revision+ (1).pdf, Researc-paper_Project Work Phase-1 PPT (21CS09).pptx, MOS-I, Unit-I (a) Simple Stress & Strain PPT.pptx, No public clipboards found for this slide. That fact justifies the suggestion made by the Commission Ill of the IABSE that a comprehensive survey be written concerning this particular bridge type. Tap here to review the details. From BS 5400 Pt4 Table 3 : E c = 31 kN/mm 2 for f cu = 40N/mm 2. 1 = Asl / bwd 0.02 Hence Effective Modulus Ec,eff = {(360 + 640) 35.2} / {640 + 360 ( 1 + 1.762)} = 21.5 kN/mm2, Modular Ratio m = Es / Ec,eff = 200 / 21.5 = 9.3 A box girder bridge is a special type of bridge in that beams have to compromise girders in the shape of empty box. The bridge has zero skew. 0.4 103 [150 (3.0 250 + 5.05 275) + 175 (0.3 87.5 + 1.35 116.7) - (20 0.15 6.7) - (195 1.05 260)] 10-6 = 119.9kNm, b) Cooling temperature difference Blockchain + AI + Crypto Economics Are We Creating a Code Tsunami? Ubani Obinna. So you do not need to waste the time on rewritings. on the inner side. Due to fatigue the stiffening effect does not work under fluctuating load. Act = 1000 650 / 2 = 325000 mm2 The closed cell which is formed has a much greater torsional stiffness and strength than an open section and it . The most common method of erecting bridge girders is direct erection by mobile crane lifting the girders (termed erection pieces) from the ground onto the bridge substructure. bridges. These are designed on the basis that the beam and links act as a pin-jointed truss. As,min = 0.26 1000 574 3.5 / 500 = 1045 mm2 Free access to premium services like Tuneln, Mubi and more. Also the girder can be constructed in wider because of the presence of two webs and . 3. Designers using Eurocode 2 for bridge design . Therefore there will be no secondary stresses due to the curvature and axial strain in the deck. Alternative Solution:If the reduction factor is not used to reduce the applied shear force actions then the allowable shear force VRd,c may be enhanced if the section being considered is within 2d of the support. 4. However these directions ii) Stress Limits carry 30 units of HB load. s = cu2(d/X - 1) = 0.0035 ( 574 / 190.6 - 1) = 0.007 > 0.00217 steel will yield. Buckling verifications at internal support P1 according to vi section 10, EN 1993-1-5 This is critical for most members in bending. From 1 April 2010 the UK design standard for concrete bridges is BS EN 1992-2 (aka Eurocode 2, part 2), this replaces BS 5400-4. Steel strain at yield = s,yield = fyk / s / Es = 500 / 1.15 / 200000 = 0.00217 The deck slab acts compositely with the steel girders. Maximum HB V = 1.1 215 kN = 237 kN > 209 HB loading critical, Maximum V = 151 + 237 = 388 kN It is usual to design reinforced concrete for the ultimate limit state and check for serviceability conditions. = As / btd and ' = A's / btd The concrete strength class will need to be C40/50. k1 = 0.6 This is critical for members in bending with significant axial load or with heavy reinforcement. Instant access to millions of ebooks, audiobooks, magazines, podcasts and more. You can download midas Civil trial version and study with it:https://hubs.ly/H0FQ60F0midas Civil is an Integrated Solution System for Bridge & Civil Engineer. Chapter 6 - Steel Structures (PDF 2.2MB) provides design guidance and plan details for steel superstructures. This means that plane sections before bending remain plane after bending, and the strain at any point is proportional to its distance from the neutral axis. A Girder is one of a superstructure. | Choice of Deck. To determine the moment of resistance of a member at failure by limit state analysis the following assumptions are made: The deisgn formulae given in clause 5.3.2.3 of the code are based on a uniform compressive stress of 0.4fcu for concrete and stresses of 0.87fy in tension and 0.72fy in compression for steel. The concrete deck may be analysed in tension or in . 0.372 103 [150 (3.0 250 + 5.05 275) + 175 (0.3 87.5 + 1.35 116.7) - (20 0.15 6.7) - (195 1.05 260)] 10-6 = 111.5kNm, Force F to restrain temperature strain : Es = 200kN/mm2 (clause 4.3.2.2) Consider worst condition before creep has occurred and Quasi-Permanent Combination Moment = 360 kNm (no secondary effects from temperature difference as deck is simply supported single span), Spacing Limit = 5(c+/2) = 5(60 + 32/2) = 380mm > 125mm OK As,min = 0.4 0.755 3.5 325000 / 500 = 687 mm2, Minimum area of longitudinal reinforcement As,min = 0.26btdfctm / fyk > 0.0013btd The span of the deck is 12.0m centre to centre of bearings. A full torsional design covering the ultimate and serviceability limit states is required when the equilibrium of a structure is dependent on the torsional resistance of the member. M = fsz = fykAsz / s = Fcz = favbXz 30 units of HB also to be considered. Bridging the Gap Between Data Science & Engineer: Building High-Performance T How to Master Difficult Conversations at Work Leaders Guide, Be A Great Product Leader (Amplify, Oct 2019), Trillion Dollar Coach Book (Bill Campbell). VRd,c = [0.24 1.59 (100 0.011 40)1/3] 1000 574 10-3 = 773 kN ( > 429 kN OK), ii) Consider a section at 2d (a = 1.148m say 1.15m) from the support (no enhancement): AsEss = 0.5bdccEc,eff Bridge Design Group. In this paper, only the transverse behavior will be discussed. wwe tag team championship 10-16. in particular that the strains caused by transient loads will not become permanent. Hence restrained temperature stresses per C = 31 10 3 12 10 -6 = 0.372 N/mm 2. Maximum ULS shear force due to gr5 = 1.35 [50.3 (10.85 + 9.65 + 8.45 + 7.25 + 6.05 + 4.85) / 12] = 267 kN, Maximum VEd from permanent actions = {[(1.35 16.3) + (1.2 3.7)] 12/2} - {1.15 [(1.35 16.3) + (1.2 3.7)]} = 128 kN Fundamentals of Prestressed Concrete Bridges. Region (ii) fails by diagonal tension causing splitting along the line from the load to the support. Model LM1 is positioned 5m clear of LM3 and will be off the deck. Design for no shear reinforcement condition then svc > 0.68 N/mm2, vc = 0.27/m(100As/bwd)1/3(fcu)1/3 www.HelpWriting.net This service will write as best as they can. m = 1 = 0.00129 (625 - 198) / (574 - 198) = 0.00146, Design crack width = 3 65 0.00146 / [1 + 2 (65 - 35) / (650 - 198)] = 0.25 mm, Design crack width = 3acrm / [1+2(acr-cnom)/(h-dc)], Maximum allowable crack width = 0.25 mm OK. 9.3 [{(1.52 + 0.06) (130 - 60 - 16) / 130} - 0.06] = 5.5 N/mm2 (Note: The loading has been simplified to demonstrate the method of designing the slab (See BS 5400 Pt2, or BD 37/01 for full design loading). reinforcing bars should lie. strip method of analysis is generally satisfactory. The Iowa Department of Transportation makes the software and . Design of Superstructure 5.1 Live load distribution factors 5.2 Dead load calculations 5.3 Unfactored and factored load effects 5.4 Loss of prestress 5.5 Stress in prestressing strands 5.6 . e = Es / Ecm = 200 / 35.2 = 5.7 k2 = 0.5 (for bending) The maximum allowable shear stress is therefore limited to a value of 0.92(fcu/1.5) as given in clause 5.3.3.1. corrosion of the reinforcement which causes the concrete to spall, thermal movements, particularly cooling from heat of hydration (called early thermal cracking), structural actions such as bending, shear or torsion. k1 = 0.6 Note: Intermediate sections between mid span and the ends of the deck will have a smaller moment than at mid span and a small shear than at the ends of the deck. Solid slab bridge decks are most useful for small, single or multi-span bridges and are easily adaptable for high skew. i) Early Age (before creep has occurred) Multi-girder bridge using variable depth girders. - 0.372 103 [130 ( 1.8 260 + 2.5 282 - 1.5 260 - 1.9 282 ) + 163 ( 0.9 141 - 0.75 141 )] 10-6 = -13.34kNm. Each tendon comprised 12 wires of 12 mm diameter made from quenched and tempered steel. Equating the tensile and compressive forces Footway loading will not affect the unit strip loading. EN 1991-1-5 Table C.1 - Coefficient of thermal expansion = 10 10-6 per C. 7.4 Box Girder Bridge Sections with Two Boxes When a reinforced concrete slab is used for the deck, the steel girders may be closed box sections or may be open sections (U - shaped) which are closed when the slab is cast. - 0.4 103 [ 130 ( 1.8 + 2.5 + 1.5 + 1.9 ) + 163 ( 0.9 + 0.75 )] 10-3 = - 508 kN Cl. The bridge was designed with a two-hinged stiffening girder system, allowing the. The test results show that this is unsafe for regions (ii) and (iii) and Mc needs to be controlled by considering the shear force. Precast concrete adjacent-box-girder bridges are the most prevalent box-girder system for short- and medium-span bridges (which typically span from 20 ft to 127 ft [6.1 m to 38.7 m]), especially on secondary roadways. Cracks in concrete can be caused by: Corrosion of reinforcement is controlled by use of suitable concrete grades and providing adequate cover to the reinforcement. - 0.372 103 [ 130 ( 1.8 + 2.5 + 1.5 + 1.9 ) + 163 ( 0.9 + 0.75 )] 10-3 = - 472.4kN, Taking moments about centroid of section to determine required moment M to restrain kt = 0.4 for permanent loading (no short-term loading included in design moment of 360 kNm) Total compressive stress in concrete = 14.9 + 1.8 = 16.7 N/mm2, Tensile stress in reinforcement = 759106 (574 - 200) 8.35 / 10.18109 = 232.8 N/mm2 All load combinations need to be checked to ensure that the stress limits are not exceeded. Looks like youve clipped this slide to already. Cracked second moment of area = As(d-dc)2 + Ec,effbdc3 / 3Es i) Crack Control Then dc/d = {[e + (e - 1)']2 + 2[e + (e - 1)'d'/d]} - [e + (e - 1)'] Hence B32 bars at 125 centres are adequate for the mid span. View example in PDF Format (Design Example 1) Download example as a Mathcad Workbook (Zip) Cast-in-Place Flat Slab Bridge Design. Second Moment of Area of Cracked Section Ic = btdc3/3 + (e-1)As'(dc-d')2 + eAs(d-dc)2 Due to the influence of this twisting moment, the most economical This is just an overview about the Reinforced Concrete Deck Girder Bridge (RCDG Bridge) the Presentation includes: Materials for Construction, Parts of a typical RCDG bridge, The Forces Acting on the bridge, etc. 11.3 Complete Joint Penetration & Partial Joint Penetration Groove Welds (PDF) 11.3 Attachment 11B American Welding Society Symbols (PDF) 11.4 1. Use Grade B500B reinforcement to BS 4449. Age of concrete at initial loading t0 = 6 days (when soffit formwork is released), h0 = 650 1 = [35 / fcm]0.7 = [35 / 48]0.7 = 0.80 2 = [35 / fcm]0.2 = [35 / 48]0.2 = 0.94, RH = [1 + 1 {(1 - RH / 100) / (0.1 h01/3)}] 2RH = [1 + 0.8 {(1 - 80 / 100) / ( 0.1 6501/3)}] 0.94 = 1.113, (fcm) = 16.8 / fcm0.5 = 16.8 / 480.5 = 2.425, (t0) = 1 / (0.1 + t00.2) = 1 / ( 0.1 + 60.2) = 0.653, 0 = RH (fcm) (t0) = 1.113 2.425 0.653 = 1.762 ArchesNatchezTraceParkway Franklin, Tennessee A Pioneering Tribute .