Complete the bridge portal model. Add moving load cases, interpret influence line output, and finalize AASHTO load combinations. Day 6 is Exam 1 — make sure your model is saved.
AASHTOMoving LoadsInfluence LinesExam Prep
— Note
Day 6 is Exam 1
Day 5 is the last class before Exam 1. The exam covers Days 1–5: ETABS basics, beam analysis, and bridge portal with AASHTO loading.
The AASHTO code requires you to position moving loads to produce the maximum effect at each critical section. Doing this by hand is error-prone — ETABS does it automatically with moving load cases.
Content Coming Soon
What an influence line actually shows: if a unit load is at position x, the influence line gives you the moment/shear/reaction at the critical section. Truck loading = convolving the truck axle pattern with the influence line.
02 — Concept
Moving load analysis in ETABS
ETABS can automatically step the HL-93 truck across the span and find the envelope of maximum and minimum effects at every section.
Content Coming Soon
Define → Load Cases → Moving Load. Vehicle class HL-93. Lane width, direction, and step size. How ETABS reports the critical position.
03 — Walkthrough
Step-by-step: Complete the bridge model
Pick up from the Day 4 file. Add the moving load case and generate force envelopes.
Detailed Steps Coming Soon
Adding vehicle lane definition. Running moving load analysis. Displaying moment envelope (max + min). Reading column axial force and base moment under Strength I combo.
04 — Check Yourself
Exam 1 self-assessment
Run through these without ETABS open. If you can't answer, review the relevant day.
Exam Review Questions Coming Soon
10 short questions covering: ETABS grid setup, load pattern vs. load case vs. load combination, HL-93 axle weights, Strength I combination factors, portal frame behaviour under horizontal load.