Available Tools
Select a category to begin- Bearing Pad
- Pier Design
- Abutment Design
- Scour Analysis
- Waterway Opening
- AASHTO LRFD
- VDOT Standards
- Design Guides
Beam Design
Steel, concrete, and prestressed beam design per AASHTO LRFD.
Simply supported steel I-girder design. Computes maximum moment, shear, and deflection for dead and live loads per AASHTO LRFD.
Reinforced concrete beam analysis. Moment, shear, and deflection calculations with AASHTO LRFD load combinations.
Prestressed concrete girder analysis. Service and strength limit state checks per AASHTO LRFD.
Beam Design Steel I-Girder
Simply supported beam analysis — AASHTO LRFD
HL-93 Loading
AASHTO HL-93 live load analysis tools for different beam configurations.
HL-93 live load analysis for simply supported beams. Computes maximum moment, shear, and reactions for design truck, design tandem, and lane load with impact factor.
HL-93 live load analysis for continuous beams over multiple supports. Influence line-based moving load analysis for multi-span configurations.
Simply Supported Beam
HL-93 live load analysis for simply supported beams. Design truck, design tandem, and lane load with impact factor.
Load Analysis
HL-93 loading, influence lines, and load combination envelopes.
AASHTO HL-93 live load analysis including design truck (HS-20), design tandem, and lane load with impact factor for simply supported and continuous beams.
Müller-Breslau influence line diagrams for moment, shear, and reactions on simply supported beams.
AASHTO LRFD Table 3.4.1-1 load combination factors for Strength, Service, Extreme, and Fatigue limit states.
Substructure
Bearing pads, pier caps, abutment walls, and foundation design.
Elastomeric and mechanical bearing pad design per AASHTO LRFD. Load calculations and dimensional requirements.
Column and cap beam design for bridge piers. Axial, shear, and moment capacity checks per AASHTO LRFD.
Wing wall and stem wall design for bridge end supports. Earth pressure and stability calculations.
Hydraulics
Scour depth calculations and waterway opening analysis.
HEC-18 scour depth calculations for bridge foundations. Local, contraction, and general scour analysis.
Waterway opening and hydraulic design checks. Flow area and clearance requirements per AASHTO.
Under Construction
This calculator is being developed. Check back soon for AASHTO LRFD compliant design calculations.
Influence Lines
Müller-Breslau influence line diagrams — Simply Supported Beam
Move a unit load across the span to trace the IL ordinate at the selected section.
References
Design standards, load combinations, and material properties
| Limit State | DC/DW | LL+IM | WS | EQ |
|---|---|---|---|---|
| Strength I | 1.25 / 1.50 | 1.75 | — | — |
| Strength II | 1.25 / 1.50 | 1.35 | — | — |
| Strength III | 1.25 / 1.50 | — | 1.40 | — |
| Strength V | 1.25 / 1.50 | 1.35 | 0.40 | — |
| Extreme I | 1.25 / 1.50 | 0.50 | — | 1.00 |
| Service I | 1.00 | 1.00 | 0.30 | — |
| Service II | 1.00 | 1.30 | — | — |
| Fatigue I | — | 1.50 | — | — |
| Material | E (ksi) | Fy (ksi) | γ (kcf) |
|---|---|---|---|
| Steel A36 | 29,000 | 36 | 0.490 |
| Steel A572 Gr.50 | 29,000 | 50 | 0.490 |
| Conc. f'c = 4 ksi | 3,605 | — | 0.150 |
| Conc. f'c = 5 ksi | 4,031 | — | 0.150 |
| Prest. Strand | 28,500 | 243* | 0.490 |
| Rebar Grade 60 | 29,000 | 60 | — |
* fpu = 270 ksi for low-relaxation strand
| Condition | Limit |
|---|---|
| Highway bridge — LL only | L / 800 |
| Pedestrian bridge — LL only | L / 1000 |
| Steel girder — DL + LL | L / 300 |
| Prestressed concrete | L / 1000 |
| Vibration-sensitive | L / 1200 |
| Load | Description | IM |
|---|---|---|
| Design Truck | 8k + 32k + 32k axles (HS-20) | 33% |
| Design Tandem | 2 × 25k, 4 ft spacing | 33% |
| Lane Load | 0.64 k/ft (no IM) | — |
- AASHTO LRFD — Bridge Design Specs, 9th Ed. (2020)
- AASHTO Standard — Standard Specs for Highway Bridges, 17th Ed.
- VDOT IIM-S&B-80 — Structure & Bridge standards
- Eurocode 1 — EN 1991-2 Traffic loads on bridges
- FHWA HIF-12-052 — Bridge Inspector's Reference Manual