EDMUND FINLEY TRISHA LOWE NICK MENCHEL ANNA SLEETER BOLIVIA BRIDGE: FINAL DESIGN

PROJECT BACKGROUND

DESIGN ALTERNATIVES

CONSIDERED ALTERNATIVES CulvertHardened Roadway Trench Cost (2)221 Materials (3)111 Tools (3)111 Material Availability (1) 211 Feasibility (2)231 Flow Capacity (1)132 Time (3)221 Maintenance (1)123 Lifespan (1)132 Failure Modes (1)132 Expertise (2)321 Adaptability (3)211 Totals384129

CONCEPTUAL DESIGN

30%/60% DESIGN

FINAL DESIGN

DESIGN DILEMMAS Site  Inaccurate/inadequate surveying data  Lack of flow data (rainfall, size of flood plain)  Lack of soil data Constructability  Limited materials  Unknown skill sets of laborers  Quantity of laborers  Time  No heavy machinery!

ASSUMPTIONS Site  Cross-section we were asked to build for is near Obrajes 1, Cross- Section 3 data, so we will use this as an approximation  Extrapolated max flow from assuming waterline is at its highest touching the bank; also considered slope of land from using surveying data of the Obrajes 1 crossing  Assumed the soil had low bearing capacity Constructability  Were able to get a materials list from NGO, Engineers in Action  Assuming unskilled labor  Time/manual labor available – can’t do much to change  Simple design

TOOLS To find internal bending moments and shear forces  Dr. Gavin’s “three_moment.m” Matlab file for continuous beams  Uses the three moment equation  Inputs: spans (between supports), live loads (point loads), dead loads (distributed loads)  Outputs: Max internal bending moments, shear forces, displacements To test design dimensions  Dr. Nadeau’s “Beam Design” excel worksheet, from CE 133 (Concrete Design)  Uses design variables and material properties to determine if, for a given cross-section, a “beam” can carry the internal moment  Also outputs reinforcement specifications

CALCULATIONS Loading conditions:  Live Loads:  Worst case scenario: a 17’ U-Haul sized vehicle, fully loaded, assumed 75% of weight is carried by back tires  Dead Loads:  Curb designed for safety  Self-weight of the components  Weight of parts being supported  Positions:  Mid-span and at supports are the worst

CURB DESIGN

SLAB DESIGN

Dead Load Live Load

SLAB DIMENSIONS ΦV n ≥ 1.6V L + 1.2V D V L = 1.74 x 10 4 N, V D = 1.52 x N … d ≥ 6.95 in + at least 1.5 in clear cover h = 22 cm (~8.66 in) Slab is 3.5m across, and 6.2m between piers

BEAM DESIGN

OUTER BEAMS Dead Load w=w curb +w slab Live Load F vehicle

INNER BEAMS Dead Load w=w slab Live Load F vehicle

BEAM DIMENSIONS M L = 35.53, M D = 18.5 (outer), (inner), kip-ft From Beam Design worksheet… Outer beam: could be 12 in x 18 in Inner beam: needs to be 12 in x 20 in Went with 12 in x 20 in Reinforcement: 1 layer, (5) #6 Longitudinal bars + #3 shear stirrups every ~14.5 in

RETAINING WALL DESIGN Piers on sides by fill and culverts needed to be designed as retaining walls Stem thickness set to 12” for constructability purposes Height: ft Base thickness: ft Base length: 10 ft Heel length: 6 ft Toe length: 3 ft

PIER AND FOOTING DESIGN Designed pier by considering a one foot section as a column Strip footing Wall thickness set at 18” for constructability purposes Base length: 1.8 m Base thickness: 0.3 m 1 #3 bar/ft

ARMORING Design a retaining wall to sit in between culverts Above top of culverts, have a second, unreinforced concrete slab, at an angle Culvert Road Bed FILL Water flow Angled slab Retaining wall

APPROACHES Not to be greater than 15 degree slope Will depend on actual site conditions and therefore will be determined on-site  Needs to follow existing roadway Sloping can begin on area over culverts as long as minimum required soil covering (depending on culvert size) is maintained

OTHER DESIGN CONSIDERATIONS

FLOW CALCULATIONS Existing railroad bridge is the limiting factor Railroad bridge – two streams; Our bridge – one stream; Comparable cross-sections = OK! Assumed water height up to bank, and used this assumption to calculate an existing flow If our culverts run full we are still OK as cross sectional area is larger than original cross sectional area Will implement a grading plan, “just in case”

TOPOGRAPHY

SATELLITE IMAGE

RAILROAD BRIDGE

CONSTRUCTION PLAN

MATERIALS/COSTS Based on volume of concrete of 40 m 3 and volume of fill of 300 m 3 and assumed 3:2:1 concrete mix ratio (ratio will be determined after speaking with locals who have experience with concrete) Summarized material list: Portland cement, gravel, sand, culverts, wood for construction, protective gear, nails/fasteners, shovels, wheelbarrows, other tools Total estimated cost: ~$9500 (US), NOT INCLUDING rebar costs  See design book for cost breakdown

OPERATION & MAINTENANCE Sign posted that only one vehicle may pass at a time… Could post weight limit as well Regular inspections should occur every 2 years (during the dry season) Culverts need to be checked ever 6 months for debris/blockage, and cleared if necessary Inspections should also be made after especially heavy storms Maintenance up to community members/Prefectura in Oruro

FINAL DESIGN

QUESTIONS?