Bridge Structural Considerations for Bridges Bridge Engineering Section

Bridge Structural Considerations for Bridges Bridge Engineering Section Technical Standards Branch BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Introduction • Bridge members must be able to carry loads applied to them. • Forces resisted by bridge members: Ø Axial forces Ø Bending forces Ø Shear forces Ø Torsional forces • This presentation considers: Ø How bridge members are stressed by loads Ø How bridge materials resist stress Ø How bridges accommodate thermal movements Bridge Engineering Section Technical Standards Branch 1 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Force Fy F (FORCE) Fx Fz Bridge Engineering Section Technical Standards Branch 2 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Stress • What is a stress? Ø Loads cause stresses Ø Stresses are the internal forces • How to calculate stress? Stress 40000 N = Force/Area = 40000/200 x 100 = 2 MPa 0 200 Bridge Engineering Section Technical Standards Branch 3 10 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Strain • It is described as the amount of deformation. • It denotes the ratio of material’s deformed dimension to its original dimension. L Strain = ΔL/L ΔL Bridge Engineering Section Technical Standards Branch 4 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Deformation & Modules of Elasticity • Elastic Deformation - It is reversible distortion of a material. • Plastic Deformation – It is the irreversible distortion of a material. • Modulus of Elasticity (E) = Stress/Strain Bridge Engineering Section Technical Standards Branch 5 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Response to Loading • Forces resisted by bridge members: Ø Axial forces Ø Bending forces Ø Shear forces Ø Torsional forces Bridge Engineering Section Technical Standards Branch 6 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Response to Loading Rigid Body • A rigid body does not deform under load. Equilibrium • When a particle is at rest or moves with constant velocity. ∑V = 0 ∑H = 0 ∑M = 0 Bridge Engineering Section Technical Standards Branch 7 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Types of Applied Stresses FORCE STRESS PLANE Tensile Stress FORCE Bridge Engineering Section Technical Standards Branch 8 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Types of Applied Stresses FORCE STRESS PLANE Compressive Stress FORCE Bridge Engineering Section Technical Standards Branch 9 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Types of Applied Stresses Compression (C) C N. A Tension (T) T Positive Moment Bridge Engineering Section Technical Standards Branch 10 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Types of Applied Stresses T Tension (T) N. A Compression (C) Negative Moment Bridge Engineering Section Technical Standards Branch 11 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Bending Stress fb C Bending Stress fb = Mc/I Bridge Engineering Section Technical Standards Branch 12 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Types of Applied Stresses FORCE STRESS PLANE Shear Stress Bridge Engineering Section Technical Standards Branch 13 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Beams – Horizontal Shear Stress HORIZONTAL SHEARING PLANE SHEAR STRESSES DIAGONAL TENSILE STRESS Bridge Engineering Section Technical Standards Branch 14 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Torsional Forces Bridge Engineering Section Technical Standards Branch 15 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Types of Supports R(H) Pin R(V) Roller R(V) M Fixed Support R(H) R(V) Bridge Engineering Section Technical Standards Branch 16 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Span Classification Simple Span Bridge Engineering Section Technical Standards Branch 17 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Shear A 20 k. N 5 A B 15 A B RA = 20 x 15/20 = 15 k. N A B RB = 20 x 5/20 = 5 k. N 15 k. N B 15 k. N ∑V = 0 Bridge Engineering Section Technical Standards Branch 18 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Shear Diagram 20 k. N 15 k. N 20 k. N 5 k. N Bridge Engineering Section Technical Standards Branch 19 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Bending Moment 5 20 k. N 15 5 k. N 15 k. N a ∑V = 0 15 k. N ∑M = 0 15 a k. Nm 15 k. N Bridge Engineering Section Technical Standards Branch 20 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Bending Moment Design 20 k. N 5 15 5 k. N 15 x 5 = 75 k. Nm 20 k. N 5 x 15 = 75 k. Nm 5 k. N 75 k. Nm Bridge Engineering Section Technical Standards Branch 21 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Span Classification Deflection Shear Moment Continuous Span Bridge Engineering Section Technical Standards Branch 22 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Span Classification Deflection Shear Moment Cantilever Bridge Engineering Section Technical Standards Branch 23 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Stress in Steel COMPRESSION YIELD STRESS LENGTHEN SHORTEN YIELD STRESS TENSION Bridge Engineering Section Technical Standards Branch 24 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Steel Bridge Members ROLLED BEAM WITH COVER PLATES RIVETED PLATE GIRDER WELDED PLATE GIRDER BOX GIRDER Bridge Engineering Section Technical Standards Branch 25 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Steel Beams – Bending Stress ROLLED BEAM WITH COVER PLATES WELDED PLATE GIRDER WITH VARYING FLANGE SIZES Bridge Engineering Section Technical Standards Branch 26 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Steel Beams – Compression Stress COMPRESSION FLANGE CROSS BRACING Bridge Engineering Section Technical Standards Branch 27 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Steel Beams – Shear Stress BEARING STIFFENERS LONGITUDINAL STIFFENERS Bridge Engineering Section Technical Standards Branch 28 INTERMEDIATE STIFFENERS BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Composite Beam CONCRETE DECK SHEAR STUDS STEEL BEAM Bridge Engineering Section Technical Standards Branch 29 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Stress in Concrete COMPRESSION STRESS LENGTHEN SHORTEN TENSION Bridge Engineering Section Technical Standards Branch 30 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Concrete Bridge Members SOLID CONCRETE SLAB CONCRETE T-GIRDER Bridge Engineering Section Technical Standards Branch 31 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Concrete Bridge Members “A” GIRDER “G” GIRDER “E” GIRDER “H”, “HC”, “VH” GIRDER Bridge Engineering Section Technical Standards Branch 32 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Concrete Beams – Bending Stress TENSION CRACK (Typ) REINFORCING STEEL Bridge Engineering Section Technical Standards Branch 33 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Concrete Beams – Shear Stress SHEAR CRACK (Typ) TENSION CRACKS REINFORCING STEEL Bridge Engineering Section Technical Standards Branch 34 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Prestressed Concrete FORMS Prestressing steel Tensioning Operation Concrete crushes if prestress too high Cracks if prestress too high May split Prestress Transfer Bridge Engineering Section Technical Standards Branch 35 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Anchorage Stress Disturbed Region b h Tensile Compressive fx = P/bh P Bridge Engineering Section Technical Standards Branch 36 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Anchorage Stress Bursting Zone 0. 34 0. 30 0. 20 0. 10 Spalling Zone 0. 05 Bridge Engineering Section Technical Standards Branch 37 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Anchorage Stress Tensile Compressive P Bridge Engineering Section Technical Standards Branch 38 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Anchorage Stress 1 2 Concentrated Load Possible Tension Cracks Bridge Engineering Section Technical Standards Branch 39 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Prestressed Concrete Bridge Members SHEAR KEY CHANNEL SHAPED FC, VF, LF, FM GIRDER BOX GIRDER (RD & RM) CAST-IN-PLACE DECK DBT GIRDER O GIRDER Bridge Engineering Section Technical Standards Branch 40 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Prestressed Concrete Bridge Members CAST-IN-PLACE DECK NU GIRDER PT DUCT ENDS OF GIRDERS PIER Bridge Engineering Section Technical Standards Branch 41 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Thermal Stress INCREASE IN LENGTH DECREASE IN LENGTH Bridge Engineering Section Technical Standards Branch 42 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Thermal Stress DECK JOINT EXP. BEARING FXD. BEARING PIER ABUTMENT Bridge Engineering Section Technical Standards Branch 43 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Thermal Stress DECK JOINT BEARING PIER ABUTMENT Bridge Engineering Section Technical Standards Branch 44 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations Stress in Concrete APPROACH SLAB BRIDGE DECK APPROACH SLAB CONTROL JOINT Bridge Engineering Section Technical Standards Branch 45 BIM Bridge Inspection and Maintenance

Bridge Structural Considerations END Bridge Engineering Section Technical Standards Branch 46 BIM Bridge Inspection and Maintenance