Materials Selection
Documents the engineering trade study used to select among candidate materials for the project's governing elements.
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Field & Laboratory · Plan, execute and document field and laboratory data collection to a defensible quality standard.
Deliverable: Materials selection trade study with weighted decision matrix and sensitivity check.
Minimum tables, figures and equations for Materials Selection
Tables — at least 6
- Table — trial sections or sizes considered, with the capacity of each and the selection decision
- Table — final selected geometry for every element: dimensions, thickness, grade, spacing, elevation
- Table — slab, beam, column and shear wall schedule with governing demand
- Table — ultimate limit state check summary: demand, capacity, ratio, pass or fail, governing clause
- Table — serviceability check summary: deflection, crack width, settlement, freeboard or velocity against its limit
- Table — factors of safety achieved against the factor required, per failure mode
Figures — at least 4
- Figure — free body diagram of each isolated element, fully labelled with loads, reactions, dimensions and axes
- Figure — shear and moment (or pressure and velocity) diagrams for each force-carrying element
- Figure — dimensioned section or plan of each designed element
- Figure — capacity versus demand plot, interaction diagram, or rating curve as applicable
Equations — at least 8
- Equation — equilibrium equations written out for each free body (sum of forces and sum of moments, or continuity and energy)
- Equation — the internal force relations V(x) and M(x), or the momentum/thrust relation, used to compute each element's demand
- Equation — the resulting demand at the critical section of each element, with numeric substitution
- Equation — the capacity expression for each element type, shown with full numeric substitution and units
- Equation — the sizing criterion that sets the final dimension (for example required area, depth or diameter)
- Equation — each limit state check written as demand over capacity with numbers substituted
- Equation — the factor of safety calculation for each failure mode checked
- Equation — punching shear, drift and deflection checks with limits
Number every table and figure (Table 4.x, Figure 4.x), caption it, and refer to it by number in your text. Number displayed equations and show the substitution with units. These counts are minimums — add whatever else your design needs.
Engineering documentation standard — required in every Chapter 4 subsection
These rules are graded on every subsection. Work that misses them is capped on technical accuracy, exhibits, codes and communication, whatever the quality of the prose.
Code and standard references
- Every requirement, factor, coefficient, limit and allowable you apply cites the governing document AND the exact section, article or sub-article number — e.g. ACI 318-19 §22.5.5.1, AISC 360-22 Chapter J, Section J3.6, AASHTO LRFD 10th Ed. Article 3.6.1.2.2, ASCE 7-22 §12.8.1, ASTM D2487, state DOT manual section, local stormwater manual chapter.
- Give the edition or year of every document the first time it appears, then use a consistent short form.
- Where a code equation is used, quote the equation number (e.g. Eq. 22.5.5.1) next to your displayed equation.
- Where you depart from a code provision, state the clause you are departing from and the engineering justification.
- List every code, standard and manual actually used in a Codes and Standards table at the start of the subsection.
Citations for statements
- Every statement of fact, value taken from elsewhere, material property, soil parameter, rainfall depth, unit cost or published method carries an in-text citation (APA) to its source.
- Field and lab data cite the report, boring log, gauge, survey file or test number and its date.
- Manufacturer data cites the product literature and revision date; software results cite the program, version and model file name.
- Uncited assertions are treated as assumptions and must appear in the assumptions table with a justification.
- Every in-text citation resolves to a full entry in the reference list.
Step-by-step calculations
- Structure every calculation the same way: (1) objective, (2) governing code clause, (3) equation in symbolic form with the equation number, (4) definition of each symbol, (5) numerical substitution, (6) result with units, (7) comparison against the limit and the pass/fail statement.
- Show the substitution line — never jump from the formula to the answer.
- Number displayed equations sequentially (Eq. 4.1, 4.2, …) and refer to them by number in the text.
- State the load or flow combination governing each calculation by name.
- Carry consistent significant figures and round only at the reported result; state the rounding convention once.
- Present repetitive element checks in a calculation table with one row per element and the same column order throughout.
Free body diagrams and figures
- Draw a separate free body diagram for each isolated element — no combined sketches standing in for several members.
- Dimension every FBD: span, depth, thickness, cover, eccentricity, embedment, slope, pipe diameter, wall height — with the dimension lines and values shown.
- Label every force, pressure, reaction and moment with its symbol, magnitude and units, and show the sign convention and coordinate axes.
- Show supports and boundary conditions explicitly (pin, roller, fixed, elastic, buoyant, hydrostatic).
- Accompany each FBD with its shear, moment, thrust, pressure or hydraulic grade diagram at the same scale reference.
- Number and caption every figure (Figure 4.x) and refer to it by number in the narrative; add a scale or north arrow to plans.
Units and notation
- Every number in text, tables, figures and equations carries its unit — no bare numbers.
- Use one unit system throughout (US customary or SI); if both appear, give the converted value in parentheses consistently.
- Check dimensional homogeneity of each equation and say so — the units of both sides must match.
- Provide a nomenclature table defining every symbol with its unit.
Checking and verification
- Every calculation is checked by an independent route — hand check against software, alternative method, order-of-magnitude estimate, or a published worked example — and the check is shown, not just claimed.
- Report demand-to-capacity ratios and factors of safety against the required values, with the source clause for each required value.
- Include a verification/checking table: item, method of check, expected, obtained, difference, accept or revise.
- Sanity-check every result (magnitude, direction, plausibility) and state the conclusion.
- Record who checked the work and on what date; flag anything still unverified as an open item.
- State limitations and the range over which the result is valid.
How to complete this section
Do this next: Read the Materials Selection lecture and the worked example so you know what "Materials selection trade study with weighted decision matrix and sensitivity check." has to contain.
Not sure how to start or how much depth is expected? Read the fully written model example for this deliverable first — it shows the structure, tables and level of justification your advisor grades against.
Site Investigation Lab — what this workspace teaches
Plan, execute and document field and laboratory data collection to a defensible quality standard.
- Planning a subsurface, structural or traffic field investigation
- Instrumentation selection, resolution, accuracy and calibration records
- GPS/GNSS positioning: datums, projections, RTK vs. handheld accuracy
- GIS data capture, attribute schemas and coordinate metadata
- Land surveying: traverses, levelling, closure and error adjustment
- Sampling strategy: representative sampling, spacing, depth intervals, replicates
- ASTM/AASHTO laboratory testing procedures and reporting requirements
- Chain of custody, sample labelling and preservation
- QA/QC: duplicates, blanks, repeatability and data validation rules
End-of-term milestones
- Tuesday, November 17, 2026 — Poster printed and ready. 36 in × 48 in poster finalized and printed one week before the November 24 showcase.
- Wednesday, November 18, 2026 — Final document package uploaded for scoring. Chapters 4–5, calculation package, drawings and appendices uploaded in the app for advisor scoring.
- Wednesday, November 18, 2026 — Poster presentation to faculty and industry. Wednesday poster session — printed 36 in × 48 in poster presented in person; industry reviewers score communication and impact.
- Wednesday, November 25, 2026 — Oral presentation and defense (scored). Scored oral presentation and defense held on Wednesday, November 25.
Materials Selection
Documents the engineering trade study used to select among candidate materials for the project's governing elements.
Section B
Engineering story
A real project situation that frames this module
It is week 4 of implementation and the construction materials engineering team has reached materials selection. Documents the engineering trade study used to select among candidate materials for the project's governing elements. The materials engineer for the agency asks one question: what establishes that weighted decision matrix?
Choosing weights after seeing the scores to justify a pre-selected answer. Because life-cycle cost comparison across candidate materials, the error does not stay local: it is carried into the design of record that drawings, quantities and cost are generated from, and every downstream product inherits it before anyone notices.
The placing crew, the owner's inspector and every downstream trade carry the consequence. On this module specifically, the exposure runs through embodied carbon comparison (kg CO2e per functional unit), and the cost of correction rises every week the mixture design, specification and acceptance testing plan moves closer to issue.
Decisions the engineer must make
- What record establishes weighted decision matrix, and is that record in the project data inventory?
- Does ISO 14044 (2006), Life cycle assessment — requirements and guidelines, govern here — and is that the edition adopted by the jurisdiction?
- What is the acceptance criterion for life-cycle cost comparison across candidate materials, and was it written before the result was known?
- Is Weighted score: S = Σ wi·xi valid over the parameter range this project actually occupies?
- If the check fails, does the team revise the mixture design, specification and acceptance testing plan or raise a change request against the locked baseline?
Photo 1. Compression test on a concrete cylinder: the measurement behind every f′c used in design.
Wikimedia Commons, public domain
Section C
Why this matters
Professional
A licensed engineer defending materials selection cites ISO 14044 (2006), Life cycle assessment — requirements and guidelines, and shows the record behind each input. Your materials selection trade study with weighted decision matrix and sensitivity check. is reviewed the same way — traceability is assessed before arithmetic.
Technical
Weighted decision matrix is what makes Weighted score: S = Σ wi·xi usable on this project rather than a formula copied from a reference. Get it wrong and every quantity derived from it is wrong by the same factor.
Safety
The failure mode this module guards against is material delivered to the field that does not match what the analysis assumed. It reaches people through local availability and lead-time risk, which is why the safety check is recorded explicitly here rather than inferred from a passing strength or performance check.
Economic
The design of record that drawings, quantities and cost are generated from is priced from this work. Quantities, unit costs and schedule float all trace to weighted decision matrix; a late correction here is paid for as a change order, not a redline.
Environmental
Environmentally, this module fixes cement content, aggregate haul distance and the carbon cost of replacement. Choosing conservatively without justification is not free — the excess shows up as material, energy and land that the project consumes for no measurable gain.
Community
Material and unit specifications must be confirmed explicitly at every interface between teams. Users who experience durability problems years after acceptance live with that outcome long after the semester ends.
Section D
Learning objectives
By the end of this module you will be able to:
- 1.Interpret weighted decision matrix, using this project's own conditions rather than a textbook case.
- 2.Apply life-cycle cost comparison across candidate materials, using this project's own conditions rather than a textbook case.
- 3.Justify embodied carbon comparison (kg CO2e per functional unit), using this project's own conditions rather than a textbook case.
- 4.Explain compatibility with existing/adjacent materials and connections, using this project's own conditions rather than a textbook case.
- 5.Compute the governing quantity from Weighted score: S = Σ wi·xi, with a unit audit on every term.
- 6.Apply ISO 14044 (2006), Life cycle assessment — requirements and guidelines, and cite the section that governs your acceptance decision.
- 7.Reproduce the worked example for two decking materials are compared and defend the interpretation of the result.
- 8.Produce materials selection trade study with weighted decision matrix and sensitivity check. at a standard the materials engineer for the agency would accept without a second revision cycle.
Section E
Instructional content
Full lecture notes with figures and governing equations
The engineering content of materials selection
Documents the engineering trade study used to select among candidate materials for the project's governing elements. That single sentence hides the substance of the module: weighted decision matrix, and life-cycle cost comparison across candidate materials. Both must be established from project evidence before anything downstream is credible.
In construction materials engineering, this work is the input to the mixture design, specification and acceptance testing plan. Embodied carbon comparison (kg CO2e per functional unit) — which is why this page asks you to record the source of every quantity, not just its value. The design of record that drawings, quantities and cost are generated from depends on it.
- Weighted decision matrix: performance, cost, durability, availability, sustainability
- Life-cycle cost comparison across candidate materials
- Embodied carbon comparison (kg CO2e per functional unit)
- Compatibility with existing/adjacent materials and connections
- Local availability and lead-time risk
Photo 1. The engineering content of materials selection in practice — Compression test on a concrete cylinder: the measurement behind every f′c used in design.
Wikimedia Commons, public domain
Governing relationships and how they are applied here
The relationships below govern materials selection. Weighted score: S = Σ wi·xi — each is valid only inside the parameter range this project occupies, so state that range before substituting.
Life-cycle cost comparison across candidate materials sets the values you place into these expressions. Any code-prescribed factor must match ISO 14044 (2006); a factor lifted from a different edition silently changes the answer.
Weighted score: S = Σ wi·xi
- wi = weight of criterion i (Σwi = 1)
- xi = normalized score of alternative on criterion i (0–1)
Photo 2. Governing relationships and how they are applied here in practice — Compression test on a concrete cylinder: the measurement behind every f′c used in design.
Wikimedia Commons, public domain
Constraints, adopted standards and the safety case for materials selection
ISO 14044 (2006), Life cycle assessment — requirements and guidelines, governs this module: Governs embodied-carbon comparison methodology ASTM E2782 (2022), Standard guide for sensitivity analysis, adds the second constraint: Used to test robustness of the weighting scheme
The safety case is explicit here. The failure mode is material delivered to the field that does not match what the analysis assumed; the people exposed are the placing crew, the owner's inspector and every downstream trade; the control that prevents it is local availability and lead-time risk together with an independent check by someone who did not perform the work.
- Controlling criterion for this module: weighted decision matrix.
- Adopted reference: ISO 14044 (2006) — cite Life cycle assessment — requirements and guidelines by number.
- Failure mode guarded: material delivered to the field that does not match what the analysis assumed.
- Evidence produced: Materials selection trade study with weighted decision matrix and sensitivity check..
Photo 3. Constraints, adopted standards and the safety case for materials selection in practice — Compression test on a concrete cylinder: the measurement behind every f′c used in design.
Wikimedia Commons, public domain
Where this method stops being valid
The worked example — two decking materials are compared — holds only while its assumptions hold. Precast concrete decking scores higher; sensitivity analysis should confirm the ranking is stable across plausible weight ranges. Outside that envelope the arithmetic still returns a number, and the number is wrong in a way no unit check will catch.
For this project, the boundary you are most likely to push is local availability and lead-time risk. If you cross it, say so in writing, bound the error, and carry the limitation into your results chapter. A disclosed limitation is professional practice; a silent extrapolation is not.
Photo 4. Where this method stops being valid in practice — Footing reinforcement and formwork before placement — the physical form of a bearing-capacity calculation.
Wikimedia Commons, public domain
Section F
Engineering workflow
Steps
- 1. Assemble the inputs this module needs — weighted decision matrix; life-cycle cost comparison across candidate materials — each with a unit and a source record.
- 2. Confirm ISO 14044 (2006) is the adopted edition and locate Life cycle assessment — requirements and guidelines.
- 3. State the assumptions and the acceptance criterion for weighted decision matrix.
- 4. Evaluate Weighted score: S = Σ wi·xi term by term, carrying one extra significant figure.
- 5. Test the result against embodied carbon comparison (kg CO2e per functional unit).
- 6. Audit units and run an order-of-magnitude check by hand before the number leaves your desk.
- 7. Obtain an independent check from a teammate who did not perform the work, and record their name and date.
- 8. Assemble materials selection trade study with weighted decision matrix and sensitivity check. and submit it to the materials engineer for the agency for review.
Decision points
- Is every input behind weighted decision matrix traceable? If not — stop and collect the record.
- Does the result satisfy life-cycle cost comparison across candidate materials? If not — revise the work, never the criterion.
- Would the correction change the design of record that drawings, quantities and cost are generated from? If yes — raise a change-control request before proceeding.
- Have you ruled out the most common error on this module — choosing weights after seeing the scores to justify a pre-selected answer?
Quality checklist
- Documented: weighted decision matrix
- Documented: life-cycle cost comparison across candidate materials
- Documented: embodied carbon comparison (kg CO2e per functional unit)
- ISO 14044 Life cycle assessment — requirements and guidelines cited by section number
- Units audited on every expression
- Acceptance criterion recorded before the result
- Independent check signed and dated
- Materials selection trade study with weighted decision matrix and sensitivity check. attached and named per the course convention
Section H
Interactive visualization
Materials Selection — step-through
Advance one frame at a time. Each frame adds one engineering decision to the previous state.
Step 1 of 6
List candidate materials meeting minimum performance.
Section I
Applicable codes and standards
ISO 14044
2006 · Life cycle assessment — requirements and guidelines
Adopted design/analysis reference governing this module.
Relevance: Governs embodied-carbon comparison methodology
Reference the section number and edition in your calculation package. Do not reproduce code text.
ASTM E2782
2022 · Standard guide for sensitivity analysis
Adopted design/analysis reference governing this module.
Relevance: Used to test robustness of the weighting scheme
Reference the section number and edition in your calculation package. Do not reproduce code text.
Section J
Worked examples
Full engineering solution format
Section K
Common mistakes and how to avoid them
- Choosing weights after seeing the scores to justify a pre-selected answer.
- Comparing materials without a common functional unit.
- Omitting sensitivity analysis on close-scoring alternatives.
- Treating weighted decision matrix as a given instead of establishing it from a project record.
- Producing materials selection trade study with weighted decision matrix and sensitivity check. without showing how life-cycle cost comparison across candidate materials was satisfied.
- Substituting into Weighted score: S = Σ wi·xi outside the range where it is valid, and reporting the number anyway.
- Missing local availability and lead-time risk, which is exactly the path to material delivered to the field that does not match what the analysis assumed.
- Designing to the average condition when the governing condition is the controlling one.
- Freezing a design before the constructability and access review that would have changed it.
- Ignoring constructability: a design that cannot be built safely is not a completed design.
- Omitting the safety check because the strength check passed.
- Referencing figures, tables, or sources that never appear in the reference list.
Section L
Industry case study
Mars Climate Orbiter loss (1999)
NASA/Lockheed Martin interplanetary mission
Official findings
- NASA mishap board found a unit mismatch (pound-force-seconds vs. newton-seconds) between two contractor teams caused loss of the spacecraft.
Field observations
- The controlling assumption was documented nowhere in the design record.
- No independent check existed at the stage where the error entered the work.
Engineering interpretation
- Interpretation below is student analysis for instructional purposes, not an official finding.
- Map the failure to a step in your own workflow and state where your process would have caught it.
Lessons learned
- Material and unit specifications must be confirmed explicitly at every interface between teams.
Source: Summarize the published investigation; cite it in your reference list. Do not reproduce copyrighted report text.
Section M
FE Civil exam connection
Handbook FE Reference Handbook — construction materials engineering section (record the section number from your handbook edition).
Exam topics
Handbook formulas
- Weighted decision score
Weak results here feed your FE Civil Academy weak-area queue for targeted practice.
Question 1 of 2
Score: 0/2In materials selection, which item must be established BEFORE the analysis is run?
Section N
Apply it to your project — Materials Selection
Complete this using your own capstone project data. Every field is saved to your project record and routed to your advisor with this module's submission.
Inputs and sources
Every value needs a traceable source.
| Quantity | Value | Unit | Source / record |
|---|
Assumptions and consequences
| Assumption | Basis | Consequence if wrong |
|---|
Self-check before submission
Section O
Design challenge
Consulting challenge — Materials Selection
Your firm has been retained to deliver the materials selection scope for a municipal client on a compressed schedule. Produce the technical position your firm would defend at a public meeting.
Client request: The client wants a defensible recommendation, the basis of design, and an honest statement of what remains unresolved.
Constraints
- Adopted local code edition governs; no exceptions without written variance.
- Budget and schedule are fixed; scope changes require change control.
- Public safety and accessibility requirements are non-negotiable.
Deliverables
- One-page basis of design
- Supporting calculation extract
- Risk and limitation statement
Evaluation
- Technical correctness
- Standard compliance
- Clarity of engineering judgment
- Honest treatment of uncertainty
Section P
Documentation workspace
Write the report section for this module in the academic editor
Section Q
File uploads
Accepted: PDF, DOCX, XLSX, CSV, PNG, JPG, ZIP
No files uploaded yet.
Section R
Deliverable and advisor review
Materials selection trade study with weighted decision matrix and sensitivity check.
Submissions route to your assigned faculty advisor and are scored independently by faculty and administrator rubrics.
Reflection
What was the hardest engineering judgment in this module, and how did you resolve it?
Section S
ABET outcome mapping
Materials selection trade study with weighted decision matrix and sensitivity check. with advisor review and dual scoring.
Assessment: Faculty rubric score and administrator rubric score on this module's submission.
Rubric: Engineering design · Target: 70% of students at or above 'meets expectations'.
Section T
References and further study
ISO 14044 (2006)
Adopted reference — cite section numbers, do not reproduce text.
ASTM E2782 (2022)
Adopted reference — cite section numbers, do not reproduce text.
Materials Selection — instructor design procedure
Course template for the calculation package format expected in the final report appendix.
NCEES FE Reference Handbook
Locate the equations used here and note the handbook section for exam recall.
Advisor meeting agenda item
Bring the unresolved decision from this module to your next weekly advisor meeting.