1: Conceptual and Architectural Design (13)
1.1: Introduction to the Designing approach of this Thesis (13) 1.2: Collocation and historic aspect of the footbridge (13) 1.3: Common footbridge static schemes (19)
1.4: Developed solution and issues (21)
1.4.1: Solution 1: inferior opposing arches (23) 1.4.2: Solution 2: cable suspended (26) 1.4.3: Solution 3: superior crossing arches (28)
1.5: Boundaries and Requirements (30)
1.6: Developing the requirement-satisfying footbridge (30)
2: Structural shear-stiffening use of glass (41)
2.1: Laminated Glass (41)
2.1.1: Introduction (41)
2.1.2: Time-Temperature behaviour (42)
2.1.3: State of the art of interlayer proprieties: PVB (46) 2.1.4: State of the art of interlayer proprieties: SGP (49) 2.1.5: Final Master-curves and Conservative Design Values (51)
2.2: Shear Glass Panels (53)
2.2.1: Static considerations (53)
2.2.2: Basic idea: glass-aluminium composite structure with no-tensile in-plane diagonal (54) 2.2.3: Interface problems, technological solution and details (59)
2.2.4: Geometric non-linearity and Buckling Failure (62) 2.2.4.1: Out-of-plane imperfection (63) 2.2.5: Stiffness-Equivalent Non-Linear FE modelling (66) 2.2.6: F.E. Modelling and Non-linear Analysis (67) 2.2.6.1: Real thickness (67)
2.2.6.2: Linear elements (68)
2.2.6.3: Non-Linear elements and non-linear solver (69) 2.2.6.4: Discussion and elements choice motivation (71) 2.2.6.5: Numerical model overview and graphic outputs (73) 2.2.7: Parametric analysis results (76)
2.2.7.1: Reference values (76)
2.2.7.2: G modulus: Time-Temperature depending (76) 2.2.7.3: Thickness (79)
2.2.7.4: Shape (Diagonal slenderness) (80) 2.2.7.5: Out-of-plane imperfection (81) 2.2.8: Global Parametric analysis of Stiffness (82) 2.2.8.1: Static behaviour of arches (82) 2.2.8.2: Parametric analysis (83) 2.2.8.3: Discussion (88)
2.2.8.4: Glass thickness design procedure (90)
3: Footbridge's global analysis (93)
3.1: Introduction (93)
3.2: Geometry and F.E. model description (93)
3.3: Supports horizontal reaction: issues and improvements (100)
3.3.1: Issues (100) 3.3.2: Lightness (101) 3.3.3: Load duration (101)
3.3.4: Wedge shape of supports (101) 3.3.5: Cable post-tensioning system (102) 3.3.5.1: Static scheme study (105) 3.3.5.1.1: Hingeless (105)
3.3.5.1.2: Horizontal displacements released (105) 3.3.5.1.3: Two hinges at the extrados (107) 3.3.5.1.4: Static scheme choice (108)
3.3.5.2: Steel relaxation issues and "auto-tensioning effect" (109) 3.3.5.3: Optimisation of axial force value for cable post-stressing (110) 3.3.5.4: Analytical pre-design of position 0 (111)
3.3.5.5: Discussion (112)
3.4: Actions (113)
3.4.1: Permanent loads (113) 3.4.2: Temperature (113)
3.4.3: Wind (114) 3.4.4: Crowd action (114) 3.4.5: Earthquake (116) 3.4.6: Accidental scenario (118)
3.4.7: Partial safety factor and scenarios' load combinations (119)
3.5: Imperfections (122) 3.5.1: Imperfection shape (122) 3.5.1.1: Global imperfection (122) 3.5.1.2: Local imperfection (124) 3.5.2: Imperfection amplitude (125) 3.6: Safety Assessing (127) 3.6.1: Global buckling (127) 3.6.1.1: EN 1993-1-6 Method (127)
3.6.1.2: IASS Working Group 8 Method (129) 3.6.2: Material (130)
3.6.3: Heat Affected Zone (133)
3.6.4: Design resistance and safety inequality (134) 3.6.5: Serviceability Ultimate State (135)
3.7: Numerical analysis and results (136)
3.7.1: Structure's shaping and pre-sizing (136) 3.7.1.1: Deck Plates (136)
3.7.1.2: Thickness vs Frequencies (137) 3.7.1.3: Rigid diaphragm needing (137) 3.7.2: Linear analysis (138)
3.7.2.1: Serviceability Limit State: maximum displacements (138) 3.7.2.2: Ultimate Limit States: Safety ratio (139)
3.7.2.3: Graphic stress output (142)
3.7.2.4: Natural frequencies and Engine-modes (144) 3.7.2.5: Response spectrum analysis (144)
3.7.2.6: Discussion of the results (144) 3.7.3: Non-linear pseudo-static analysis (146)
3.7.3.1: Introduction (146)
3.7.3.2: Time and Temperature depending of Material behaviour: procedure (146) 3.7.3.3: Half live load & Temperature increasing scenario (147)
3.7.3.4: Half live load & Temperature decreasing scenario (147) 3.7.3.5: Discussion (148)
3.7.4: Accidental scenario (151)
3.8: Vibration and Comfort assessing (152)
3.8.1: Introduction (152) 3.8.2: Issues (152) 3.8.3: Improvement (153)
3.8.4: Standards and JRC-Scientific and Technical Report (154) 3.8.4.1: Step 1: Evaluation of Natural Frequencies (154)
3.8.4.2: Step 2 : Check of critical range of natural frequencies (154) 3.8.4.3: Step 3 : Assessment of Design situation (155)
3.8.4.3.5: Traffic classes (156) 3.8.4.3.6: Comfort classes (156)
3.8.4.3.7: Assessed design situations (157) 3.8.4.4: Step 4: Damping (157)
3.8.4.5: Step 5: Determination of maximum acceleration (159) 3.8.4.6: Step 6: Check of comfort levels (161)
3.8.4.7: Step 7: Check of criteria for later lock-in (161) 3.8.4.8: Flowchart of footbridge vibration assessing (163) 3.8.5: Numerical analysis and results (164)
3.8.5.1: Natural frequencies and Engine-modes (164) 3.8.5.2: Pedestrian load (165)
3.8.5.3: Linear Harmonic analysis (165) 3.8.5.4: Time-history non-linear analysis (167) 3.8.5.5: Discussion of results (168)
3.8.5.5.8: Natural Frequency (168)
3.8.5.5.9: Footbridge harmonic dynamic response (169) 3.8.5.5.10: Non-linear time-history dynamic analysis (171) 3.8.5.6: Comparison with existing footbridges (172)
4: References (175)
5: Appendixes (179)
5.1: Drawings (179) 5.2: Rendering (179)
5.3: Ancient plan of Old Pisa (179)
5.4: Official Communication about Aluminium structures from the Italian "National Authority for Public Constructions" (179)
