Construction Guide

Quick Reference Card - print out for job site

4-Week Build Schedule

Complete step-by-step instructions for building your bridge abutment from site preparation through final inspection.

📅 Construction Timeline

Total Project: 4-6 Weeks

🛠️ Tools & Equipment Needed

Essential Tools

Safety Equipment

📋 Week-by-Week Guide

Week 1: Site Preparation

Day 1-2: Excavation

Task: Excavate foundation area
Dimensions: 9' long × 3' wide × 1.5' deep
Goal: Reach firm bearing soil

Steps:

  1. Mark excavation area with stakes and string
  2. Remove all topsoil, organics, and soft material
  3. Dig to firm bearing soil (squeeze test: forms ball, not muddy)
  4. Level bottom within ±1”
  5. Inspect for wet spots or soft areas

Quality Check:

Day 3: AB3 Base Installation

Task: Install and compact aggregate base
Material: 0.75 tons AB3 aggregate
Thickness: 12" (three 4" lifts)

Steps:

  1. Place vapor barrier on bearing soil
  2. Spread first 4” lift of AB3
  3. Compact with plate compactor (3-4 passes)
  4. Check compaction (should be firm, no movement)
  5. Repeat for two more 4” lifts
  6. CRITICAL: Get compaction test (95% minimum)

Quality Check:

Day 4: Ground Anchors

Task: Install fiberglass ground anchors
Quantity: 6 anchors
Depth: 6' minimum

Steps:

  1. Mark anchor locations (2 rows × 3 columns)
  2. Use rotary hammer to drive 8’ fiberglass rebar
  3. Drive 6’ deep minimum
  4. Leave 2’ protruding above AB3
  5. Check plumb with level

Spacing:

Week 2: Base Slab

Day 5: Base Rebar Installation

Task: Install complete base slab rebar grid
Bars: R1 (2) + R2 (8) = 10 bars

Steps:

  1. see guide
  2. Set concrete chairs (3” height) on AB3
  3. see rebar cage visualizations
  4. Install R1 bars (2 longitudinal, 9’ long)
    • Run front-to-back along 2’ depth
    • Space 30” apart
  5. Install R2 bars (8 transverse, 3’ long)
    • Run across 8’ length
    • Space 12” on center
  6. Tie all intersections with wire
  7. Verify 3” cover on all sides

Quality Check:

Day 5 (continued): Bearing Plates

Task: Position steel bearing plates
Quantity: 2 plates (12" × 12" × 1/2")

Steps:

  1. see guide
  2. Position plates on elevated chairs
    • Plate 1: 30” from left edge
    • Plate 2: 66” from left edge
    • Both: 18” from front edge
  3. Check elevation (must be at final wall top: 36” above AB3)
  4. Level plates carefully (laser level)
  5. Wire to rebar to prevent movement
  6. Double-check positions!

Quality Check:

Day 5 (continued): Drainage Pipes

Task: Install drainage pipes through base
Quantity: 2 pipes (4" PVC, 3' long)
Slope: 2% toward creek side

Steps:

  1. Position pipes between bearing plates
    • Pipe 1: At 36” from left
    • Pipe 2: At 72” from left
  2. Front elevation: 6” above AB3
  3. Back elevation: 3.6” above AB3 (2% slope)
  4. Support pipes so they don’t move during pour

Day 6: Base Slab Pour

Task: Pour and finish base slab
Concrete: 0.6 CY (order 1.0 CY with wall)
Specification: 3000 PSI, 4" slump

Steps:

  1. Build forms (1’ high around perimeter)
  2. Oil forms for easy removal
  3. Final inspection of rebar and plates
  4. Pour concrete
  5. Vibrate thoroughly (especially around plates!)
  6. Strike off level
  7. Float smooth
  8. Cover immediately with plastic
  9. Begin moist curing

Quality Check:

Days 7-13: Cure Base

Task: Cure base slab
Duration: 7 days minimum

Daily Tasks:

Week 3: Wall Construction

Day 14: Wall Rebar Installation

Task: Install all wall rebar
Bars: R3 (8) + R4 (8) + R5 (16) = 32 bars

Steps:

  1. Mark vertical bar locations on cured base
    • 8 positions along 8’ length
    • 12” on center
  2. Install R3 bars (8 front verticals, 3’ long)
    • Bottom 6” laps into base
    • 24” vertical through wall
    • 6” hook at top
  3. Install R4 bars (8 back verticals, identical to R3)
  4. Install R5 horizontal ties (16 bars, 3’ long)
    • Level 1: 6” above base (~1’ elevation)
    • Level 2: 6” below wall top (~2.5’ elevation)
    • 8 bars per level
    • Hooks wrap around verticals
  5. Verify 3” cover on all faces
  6. Tie all intersections

Quality Check:

Day 15: Wall Forms

Task: Build and install wall forms
Height: 2' (24")
Length: 8'

Steps:

  1. Cut 2×6 or 2×8 form boards
  2. Build form panels (8’ long × 2’ high)
  3. Position forms on both sides of wall
  4. Brace securely (concrete is heavy!)
  5. Check plumb with level
  6. Oil forms

Quality Check:

Day 16: Wall Pour

Task: Pour wall
Concrete: 1.2 CY (part of 2 CY order)
Pour: Single lift if possible

Steps:

  1. Final inspection of rebar and forms
  2. Make test cylinders (6 minimum)
  3. Pour concrete in 12” lifts
  4. Vibrate each lift thoroughly
  5. Pay special attention to:
    • Around bearing plates
    • At corners
    • Where rebar is dense
  6. Strike off at exact elevation
  7. Trowel smooth if desired
  8. Cover with plastic
  9. Begin moist curing

Quality Check:

Days 17-23: Cure Wall

Task: Cure wall
Duration: 7 days minimum

Daily Tasks:

Week 4: Finishing

Day 24: Form Removal

Task: Remove all forms
Wait: Minimum 7 days after pour

Steps:

  1. Carefully remove form boards
  2. Inspect concrete quality
  3. Check for:
    • Honeycombing (voids)
    • Cracks (hairline OK)
    • Proper consolidation
  4. Patch any minor defects

Days 25-26: Backfill

Task: Backfill behind wall
Material: Granular material (not clay)

Steps:

  1. Place granular backfill
  2. Compact in 6” lifts
  3. Do NOT overload wall yet
  4. Slope away from wall for drainage

Day 27: Drainage

Task: Complete drainage system

Steps:

  1. Extend drainage pipes to outlets
  2. Install screens/grates
  3. Test water flow
  4. Ensure 2% slope maintained

Day 28: Pre-Inspection

Task: Self-inspection before official inspection

Use Checklist:

🔍 Quality Control Checkpoints

Before EVERY Concrete Pour

  1. ✓ Rebar: size, spacing, cover, cleanliness
  2. ✓ Forms: plumb, braced, oiled
  3. ✓ Weather: temperature 40-90°F
  4. ✓ Bearing plates: position, elevation, level
  5. ✓ Mix design: 3000 PSI minimum
  6. ✓ Test cylinders ready

During EVERY Pour

  1. ✓ Slump test: 4” ±1”
  2. ✓ Vibration: thorough, systematic
  3. ✓ No cold joints (keep moving!)
  4. ✓ Strike off at correct elevation
  5. ✓ Cover immediately after finishing

After EVERY Pour

  1. ✓ Moist curing starts immediately
  2. ✓ Covered with plastic
  3. ✓ Test cylinders curing with structure
  4. ✓ Daily moisture checks

⚠️ Common Mistakes to Avoid

❌ #1: Insufficient AB3 Compaction

Problem: Settlement after construction = catastrophic failure

Solution: Compact in 4" lifts, get 95% compaction test

❌ #2: Poor Concrete Cover

Problem: Rust within 5-10 years

Solution: Use proper chairs, check cover before AND after tying

❌ #3: Bearing Plates Misaligned

Problem: Eccentric loading = cracking

Solution: Measure three times, use laser level, verify before pour

❌ #4: Premature Loading

Problem: Cracking, reduced strength

Solution: Wait full 14 days, check test cylinders

❌ #5: Inadequate Vibration

Problem: Honeycombing = weak structure

Solution: Rent vibrator, use systematically, stop when bubbles stop

📱 Construction Progress Tracking

Use our Construction Checklist PDF to track your progress week by week.

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