TheBridgeEng

Elastomeric bearing — first sizing

Elastomeric bearing pad

First sizing of a steel-reinforced elastomeric bearing to AASHTO LRFD Method A (§14.7.6). Give the vertical service load and the shear movement — the same movement the Expansion-joint tool computes — and the tool proposes a pad, or checks one you set yourself. Service-level planning aid; rotation, anchorage and low-temperature grade belong to detailed design.

The tool finds the smallest pad (50 mm steps) that passes every Method A check.

Bearing section — to scale Shear deformation Δs

Proposed pad — plan L × W

—

Compressive stress—

σs vs min(1.25GS, 8.62 MPa)

Movement demand—

2Δs vs elastomer h_rt

Stability H / (min(L,W)/3)—

total height vs stability limit

Vertical service load1000kN

20026005000

Total service (DL+LL) reaction on one bearing.

Shear movement Δs30mm

060120

One-way movement at this bearing — take it from the Expansion-joint tool.

Elastomer hardness

G_min in MPa (AASHTO). 70 duro is used for sliding bearings, not laminated pads.

Internal layer thickness

Covers = half the internal layer; 3 mm steel shims between layers.

Your trial pad

Length L (longit.)300mm

1506751200

Width W (transv.)450mm

1506751200

Internal layers n4ea

2916

Check (Method A)	Value	Limit	Status

Field notes — what to watch for

Plan area comes from stress, but thickness comes from movement — the elastomer absorbs translation by shear, and total rubber thickness must be roughly twice the movement. A pad that passes compression and fails rotation lifts at one edge and walks; check both. Anchor the pad detailing to the maintenance question: can it be jacked and replaced?

Inputs are saved on this device · reset to defaults