P14416: Concrete Arborloo Base. System Design Review October 1, 2013

Transcription

1 P14416: Concrete Arborloo Base System Design Review October 1, 2013

2 Team Introduction & Roles Member Victoria Snell (ISE) Evan Burley (ME) Joe Omilanowicz (ME) Mac Keehfus (ME) Anthony Deleo (ISE) Role Project Manager Engineer Engineer Engineer Engineer

3 Agenda Background/Problem Statement Open Items Specifications Benchmarking/Concrete Introduction Concept Generation Concept Selection Engineering Analysis Test Plan Materials Considered Potential Risks Plans Moving Forward

4 Arborloo A latrine-like sanitation device designed to function over a small pit and to be moved to a new pit when filled Utilize compost by planting tree in used pit Purpose to provide affordable sanitation in poor, underdeveloped areas Originally designed for use in Zimbabwe

5 Problem Statement Current State Today s arborloo takes two days to install and is not easily transportable. The current design is also not socially appealing to the Haitian population. Desired State Provide an affordable concrete base that is easy to move and install. The desired base should be aesthetically pleasing to users and a worthwhile purchase for sanitation improvements rather than storage or social status. Project goals Low cost (<$50 to purchase) Base design that safely covers an diameter, 3-4 ft. deep hole Easily constructed using simple hand tools Portable Resistant to environmental damage Has modular design Haitians want to purchase Constraints Proposed budget= $1500 Base must be relatively lightweight for transportation Base must be made using concrete

6 Open Items Safety Rating Considered separately from main function of supporting weight Other factors (tripping and slipping hazards) don t influence design decisions as significantly Clarified that time constraint refers to home setup Changed tripping hazard definition to comply with OSHA standard Changed survey method to choosing between multiple alternatives

7 Customer Requirements Importance Scale 9 The system costs less than $50-$100 to users (at production level quantities). The system is lightweight and moveable (by donkey or person walking for up to 6 hours) The system can be installed in less than 4 hours. The system can be installed with simple hand tools. The system confers social status to the owner. The system supports the user over an arborloo hole in diameter, 3-4 feet deep 3 The system is safe to use for users (falling, tripping, slipping, moving to new hole). The system keeps pests out of the pit. The system looks modern in a Haitian context. The system is welcoming and comfortable. The system can be financed in parts. 1 The system is a product, not a DIY project. The system resists weather and pest damage. The system minimizes environmental impact throughout the lifecycle.

8 Importance Scale - 9 Cost Easy Transport Customer Requirements Quick to Assemble Strength Importance Scale - 3 Safe Visually Appealing. Based on Concept Selection Criteria Comfortable Accommodates Large Hole in Ground Modular

9 Engineering Requirements

10 Peter Morgan s Arborloo DIY Project Composition Bag of cement Good river sand Thick wire Mounted on a ring beam of bricks or concrete Molded from bricks Addition of soil, wood ash & leaves creates compost

11 Other Arborloos? Current concrete Arborloos have typical cement, sand, and gravel composition Wire or rebar for reinforcement Flat or slightly domed circle and square shaped Catholic Relief Services reports $5-8 for Arborloo in Ethiopia 2-3 slabs made from one bag of cement

12 Benchmarking Effective fiber volume is at a 0.75% fraction Variety of Different aggregates and reinforcements Reinforcement patterns Material Properties of different fibers Haitian Perspective * Based on Pedro Cruz-Dilone Paper

13 Why Use Concrete? Available in Haiti Tough/ Durable Strong in compression Only basic Tools are needed Minimally skilled Haitian Mason can make Materials are cheap Easy to provide good tensile strength with the additions of reinforcement s Test standards already created and available

14 Concrete Background Holly Holevinski Cement + water = paste Aggregates: Coarse (>1/4 ) Fine (<1/4 ) Reinforcement (rebar) Fiberglass, plastic, steel Add mixtures: reduce weight Air-entrainment Foaming materials Accelerators and retarders

15 Concrete Background 5 types of Portland cement Types I V Type I & II General use Type IV- High Early Reaches its maximum strength within 24 hours Window when paste is moldable 0-90 minutes Final set at 120 minutes 3000 psi goal for slab

16 Concrete Background Concrete Tips: Concrete cannot go below 80% RH during cure process Rebar should not touch any open areas Use plastic to keep moisture in, spray concrete regularly if possible Mix parts of Portland cement with cheap substitutes (fly ash, silica fume) Concrete must be at least 30% Portland cement

17 Functional Decomposition

18 Functional Architecture

19 Functions Covers Hole in Ground Support Weight (reinforcement) Support Weight (aggregates) Transports Waste Concept Generation Easy to Transport Simple to Assemble Withstands Damage During Transport Remains Stable Easily Cleaned Withstands Environmental Damage Reduces Odor Stability No Pests Modular Interface with Shelter Aesthetics Ergonomic

20 Concept Generation: Key Functions Functions Covers Hole in Ground Support Weight (reinforcement) Support Weight (aggregates) Transports Waste Easy to Transport

21 Concept Selection Peter Morgan s as Datum A B C D E F G H Dome Cone Peter Morgan's Oval "X" "Lincoln Logs" Square Triangular (hollowed out) (hollowed out) Arborloo (Puzzle) Selection Criteria Low cost Easy to transport Safe Quick to install Visually appealing High strength Comfortable holes Modular semesters Sum + 's Sum 0's Sum -'s Continue? Y Y - N N - Y

22 Concept Selection Dome as Datum A B C D E F G H Peter Morgan's Cone Dome Oval "X" "Lincoln Logs" Square Triangular Arborloo (hollowed out) (hollowed out) (Puzzle) Selection Criteria Low cost Easy to transport Safe Quick to install Visually appealing High strength Comfortable holes Modular semesters Sum + 's Sum 0's Sum -'s Continue? Y Y N Y Y

23 Selected Concept #1 - Dome PROS Round edges allow for compressive strength advantages Attractive design Safe Comfortable CONS Difficult to make modular Difficult mold design Hard to transport Cost

24 Selected Concept #2- Hollow Puzzle PROS Comfortable Visually appealing Modular Pieces provide support for each other Piece Cone CONS Less safe Mold design Cost Long assembly time

25 Selected Concept #3 - Triangle PROS Less Material Simple Mold Design Low Cost Visually Appealing CONS Difficult to transport Not modular Difficult to interface with hole Stress concentrations in corners

26 Concept Selection #4- Circular Peter Morgan s PROS Accommodates large hole in ground Safe Relatively easy mold Easy to transport CONS Not modular Not comfortable Not visually appealing

27 Engineering Analysis Using ANSYS and material properties of standard concrete: Poisson s Ratio: 0.3 Elastic Modulus: 4e6 psi Assumed an applied Pressue of 500 lbs

28 2D Circle and Triangle Slabs

29 3D Dome and Cone Slabs

30 Test Plan Compression Test Verify strength of concrete Determine how aggregates/fillers effect strength of concrete Flexural Test (with/without reinforcement) Determine advantages of certain reinforcement concepts Tensile Strength Transportation User Interaction

31 Flexural Test Compression Test

32 ASTM Standards C150- Standard Specification for Portland Cement C330-Standard Specification for Lightweight Aggregates for Structural Concrete C470-Standards for Specification for Molds for Forming Concrete Test Cylinders Vertically C39- Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens C78-Standard Test Method for Flexural Strength of Concrete

33 Materials to Test- Aggregates (course and fine) Effect the weight and compressive strength of concrete: Chopped up rubber tires Sand Coconut shell Bean bag filler Glass bubbles Grass/leaves Styrofoam Ground up water bottles Clay

34 Materials to Test- Reinforcements Effect the strength by absorbing some of tensile stresses Rebar Snow fence Window screen Chicken wire Corrugated metal sheets Steel rods Fishing line Nylon rope Onion bags (mesh) Plastic bags Bicycle spokes Banana fibers Sisal fibers

35 Likelihood Severity Importance Risk Assessment Risk Item Effect Cause Action to Minimize Risk Owner Spend more than our budget allows Hole in concrete is deemed unsafe Design is too hard to transport Base cracks under minimal load Unable to purchase necessary items Child could fall through Device becomes immobile defeating the purpose of improved sanitation Useless device Overspending on unnecessary materials Inability to follow customer requirements Not modular and/or too heavy Lack of reinforcement Poor concrete mixture Develop a Bill of Materials that is well under our given budget Budget Tracker Pay close attention to the safety of the hole size relative to the rest of the base Check against playground standard after design drawings are done Research ways to make concrete more light and implement that into our design Research and test lighter aggregates Test multiple times and recreate Obtain multiple reinforcement materials that increase tensile strength by November Research ways to mix concrete and talk to concrete experts Anthony Mac Joe Mac/Evan Team

36 Other potential issues Instructions do not allow for easy assembly or installation Plan: Provide simple picture instructions Aggregate mixtures are inconsistent and unrepeatable Plan: Document every quantifiable value for mixtures and measurement Base is not attractive to purchase Plan: Research through interviews/surveys with Haitian locals and visitors Time constraint (EPA in DC) Stay ahead of Mycourses outline Work during Intercession break

37 Moving Forward Specimen testing Continue aggregate research Optimize concrete performance Create more detailed designs Update EDGE Continue to consider Customer requirements as we make decisions

38 Additional Questions/Opinions? Shapes Feasibility Additional materials to test