T1-L18: Bridge Construction — Building Your Trusses

Name:

Class:

Date:

Folio: pp. 76–78

Outcomes: TE4-SAF-01 TE4-PPM-01 TE4-MSC-01 Folio pp. 76–78

Learning Intention

We are learning to construct our bridge using safe techniques and the design process.

Success Criteria

I can safely use craft sticks and PVA glue
I can build two identical side trusses
I can use triangulation in my bridge structure
I can document my construction progress

✎

Do Now

WHS Safety Briefing — Read the 5 safety rules below and explain why each is important.

Rule #	Safety Rule	Why is this important?
1	PVA glue on skin — wash immediately
2	Craft knives only with teacher permission
3	Workspace clean and organised
4	No eating or drinking near materials
5	Report all accidents to teacher

📚

Key Vocabulary

Standard: Fill in the definition. | Support: Definitions shown in grey — read and copy into your folio. | Extension: Use each term in a sentence.

Term	Definition	Use in a sentence (Extension)
Truss	A rigid framework of members using triangles to distribute load
Member	A single structural element — one craft stick
Joint	A point where two or more members connect — a glued overlap
Cross-brace	A short member connecting two parallel trusses to prevent twisting
Deck	The flat surface on top where load sits — the road surface
Alignment	Making sure both side trusses are identical in shape and size

✅

Activity 1: Safety Acknowledgement (Folio p. 76)

Read each safety rule carefully. Tick to confirm you understand and will follow it.

✔	Safety Rule	I understand and will follow this rule
	PVA glue on skin — wash immediately with water	Tick to confirm
	Craft knives only with teacher permission and supervision	Tick to confirm
	Keep workspace clean and organised at all times	Tick to confirm
	No eating or drinking near materials	Tick to confirm
	Report all accidents to teacher immediately	Tick to confirm

Student signature (type your name):

📝

Activity 2: Build Sequence Overview (Folio p. 76)

Your bridge will be built over multiple lessons. Here are the 5 key steps:

Step	Build Stage	Does this apply today?
1	Build 2 side trusses (flat on desk)
2	Let trusses dry completely
3	Stand up trusses and add cross-bracing
4	Add deck on top
5	Let dry and prepare for testing

💧

Activity 3: PVA Glue Technique (Folio p. 77)

PVA Gluing Tips:

Apply a thin, even layer on BOTH surfaces
Press firmly for 10 seconds
Clamp with rubber bands while drying
Common mistake: More glue ≠ stronger! Excess glue weakens joints.

▲

Activity 4: Build First Triangle — Guided Practice (Folio p. 77)

Follow these steps to build your first triangle. This is the building block of your truss.

Step	Instruction	Done? Notes
1	Lay 3 sticks in a triangle shape on a flat surface
2	Overlap sticks by 1 cm at each vertex (corner)
3	Apply thin PVA glue to BOTH overlapping surfaces
4	Press and hold for 10 seconds at each joint
5	Clamp joints with rubber bands

Sketch your completed first triangle:

🔨

Activity 5: Build Side Truss 1 (Folio p. 77)

Using your design sketch from last lesson, build your first side truss flat on the desk.

⚠ Construction Checklist — Truss 1

	Building flat on desk
	Using lap joints (1–2 cm overlap)
	Thin, even glue layer
	Clamping every joint
	Multiple triangles in the truss

🔨

Activity 6: Build Side Truss 2 (Folio p. 78)

Build a second truss that is identical to Truss 1.

💡 Tips for Matching Trusses

Place Truss 1 beside your work as a reference
Count the same number of members and triangles
Measure key dimensions to match

📝

Activity 7: Production Log (Folio p. 78)

Detail	Your response
Date:
Sketch of completed truss:
What went well?
What was challenging?

📏

Activity 8: Alignment Check (Folio p. 78)

Place both trusses side by side and check they match.

Check	Yes / No	Fix needed?
Same length?
Same height?
Same number of triangles?
Joints line up?
Both lie flat on the desk?

🔵 Support — Construction Assistance

Use these supports if you need extra help:

Template truss design: Lay sticks on top of the printed template
Pre-cut sticks: Ask teacher for pre-measured pieces
Teacher assist: Get help with your first 2–3 joints
Simplified truss: Build with 3–4 triangles instead of more
Visual step-by-step card: Follow the picture guide at your desk

Word Bank

trussmemberjointtriangle lap jointPVAalignmentclamp

🟠 Extension — Advanced Construction

Advanced truss design: Are you building a Howe, Pratt, or Warren truss? Explain the difference and why you chose yours.

Calculate: How many members (sticks) and joints does your truss have?

Number of members:

Number of joints:

Number of triangles:

Peer mentor: Help a classmate with their construction. What advice did you give?

Early finisher: If your trusses are dry, begin cross-bracing.

🎫

Exit Ticket — Reflection

1. What was the most challenging part of building today?

2. What would you do differently if you started again?

3. On a scale of 1–5, how confident are you that your trusses are identical? Explain.

✅

Self-Assessment

Success Criteria	Got it 🟢	Nearly there 🟠	Need help 🔴
I can safely use craft sticks and PVA glue	●	●	●
I can build two identical side trusses	●	●	●
I can use triangulation in my bridge structure	●	●	●
I can document my construction progress	●	●	●