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\begin_layout Title
Structural Design of AguaClara Plants
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\begin_layout Abstract
The AguaClara team at Cornell has focused on the unit process and hydraulic
 design of municipal drinking water treatment plants and has left the structural
 design to the Honduran engineers who are also responsible for site surveys
 and construction supervision.
 There are three opportunities for structural design work and research at
 Cornell.
 Although the structural design based on locally manufactured brick, re-bar,
 mortar and poured concrete columns is a common construction technique in
 Honduras, there may be opportunities to further optimize this construction
 technique and there may be alternate construction techniques that would
 be more cost effective.
 As a first step it would be beneficial to evaluate the current construction
 techniques using modern tools of structural analysis.
 The second opportunity is to begin to automate the structural design.
 The third opportunity for research would be to develop a set of material
 strength tests that could be used at AguaClara construction sites for quality
 control.
 
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Students 1
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Skills Structural engineering
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\begin_layout Section
Structural Analysis of AguaClara Plants
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\begin_layout Standard
AguaClara plants use a poured concrete slab and stacks of bricks (see Figure
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) with both horizontal and vertical re-bar for reinforcement.
 The relatively shallow tanks are approximately 1.6
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m to 2
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m deep and thus the hydrostatic forces are relatively small.
 This has made it possible to construct walls that are only 15 cm thick
 when finished.
 
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Poured slab reinforced foundation and bricks with both horizontal and vertical
 re-bar at the Agalteca water treatment plant.
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\begin_layout Standard
The structural analysis of AguaClara plants should begin with an overview
 of structural analysis methods that could be applied to these tank walls.
 The methods should include both approximate analytical approaches and more
 sophisticated analytical methods that facilitate analysis of the entire
 structure.
 After the available tools are identified the structural design should be
 evaluated using one or more approaches.
 The failure modes need to be characterized with special attention to the
 need of the tanks to be waterproof and thus to have minimal cracking.
 After the structural design is evaluated, opportunities for improving the
 current design can be explored.
 For example, could the addition of a steel mesh on the outside of the brick
 that would be embedded in the plaster improve the strength of the walls?
 Could the amount of re-bar used in the walls be safely reduced?
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\begin_layout Standard
There is some indication that reinforced masonry unit walls are sufficiently
 complex that they are beyond the computational scope of commercial structural
 design software.
 This assessment needs to be corroborated and if it is the case, then a
 strategy for design needs to be developed.
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\begin_layout Standard
Another strategy would be to propose a different construction technique.
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\begin_layout Section
Automate Structural Design
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\begin_layout Standard
A key innovation of the Cornell AguaClara team is the online AguaClara design
 tool that creates the unit process and hydraulic design for AguaClara facilitie
s.
 The same scalable design approach could be used for the structural design
 as well.
 It is not yet clear if it is appropriate for the Cornell AguaClara team
 to design the structure.
 We will need to carefully address issues of liability if we provide structural
 design guidance.
 It should be possible to have the structural design reviewed by professional
 engineers prior to inclusion in the design tool to ensure that the structural
 designs are robust.
 The rational for adding structural design to the online design tool is
 that it will further reduce implementation costs.
 
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\begin_layout Standard
The structural design will need to be varied based on the availability of
 materials.
 This added complexity needs to be carefully assessed to create a design
 methodology that can scale globally.
 
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\begin_layout Section
Site Evaluation of Material Properties
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\begin_layout Standard
The use of locally available materials often means that the strength of
 the materials is unknown or poorly characterized.
 This leads to uncertainty in the structural design and a need to include
 large factors of safety in the design.
 It would be very useful to develop test methods that could be implemented
 at the construction site to evaluate the strength of the material as well
 as to maintain quality control of construction.
 The test methods could be evaluated relative to laboratory test methods
 used in the Bovay test facility at Cornell.
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