Custom Elastomeric Bearing Pads, Leveling Pads & Structural Isolation

No pad is, and no honest supplier claims otherwise: AASHTO M251 and ASTM D4014 are specifications a bearing design is checked against, and the bearing design belongs to the engineer of record. What a pad carries is its material documentation: the polymer type (Type CR chloroprene), the durometer per ASTM D2240, and the tensile, heat-aging, compression-set, and ozone data on its TDS. H-O supplies the pad to the durometer, thickness, and plan the design calls for, plus the TDS; the pad supports a design evaluated to those standards. [1]

By allowable compressive stress and by rotation, not by thickness. Start from the bearing (dead + live) load and the bearing area to get the working stress, then check it against the allowable for the pad's type, durometer, and shape factor (loaded area ÷ area free to bulge): a plain neoprene pad carries on the order of 800 psi, a random-oriented-fiber pad far more (roughly 1500–2000 psi per the vendor TDS), and a steel-laminated bearing per AASHTO LRFD 14.7.6 the most.

Then choose durometer to the required rotation. Verify every value against the specific vendor TDS and the governing spec. [11]

To the rotation and the load. Shore 50 (softer) accommodates the most end rotation and is the choice where a beam deflects and the pad must not let the member bear on an edge; Shore 60 is the all-purpose middle; Shore 70 (harder) carries the highest load and high temperature but rotates least. Hardness is measured per ASTM D2240, and AASHTO M251 gives the hardness tolerances in its appendix.

Send the required rotation with the load; the durometer follows, and a pad chosen for load alone without checking rotation is the classic edge-bearing failure. [4]

A random-oriented-fiber (ROF) pad is a fiber-reinforced elastomeric leveling and bearing pad that carries far more compressive stress than a plain elastomeric pad, roughly 1500–2000 psi per the vendor TDS, and it is supplied to the AASHTO LRFD 14.7.6.1 / 14.7.6.2 and legacy 18.10.1 bearing provisions.

Reach for it where the setting or bearing stress exceeds what plain neoprene should carry, or where a high-stress leveling pad is needed under precast, steel, or panel bearing. Cork-rubber is the related load-bearing leveling composite. Confirm the specific capacity against the vendor TDS and the governing spec. [11]

Not as a D4014 bearing: ASTM D4014 covers only Type CR (chloroprene / neoprene) and Type NR (natural rubber). EPDM is an excellent general weather-durable elastomer, strong against ozone and UV, so it is a good choice for exterior non-bridge equipment setting and leveling pads where weathering dominates, but it is not one of the D4014 bearing elastomers. For a bridge or structural bearing evaluated to AASHTO M251 / ASTM D4014, use chloroprene (neoprene). Match the polymer to the exposure and the governing spec. [8]

Different jobs, different sizing. This page's bearing and leveling pads are static load-transfer bearings: they carry the sustained load and hold the level, and they are sized by allowable compressive stress and required rotation. A vibration-isolation pad is a dynamic component tuned by natural frequency to isolate a running machine from structure-borne vibration, and it is sized by the disturbing frequency and the required transmissibility.

Conflating the two is a real failure: a static bearing on a dynamic-isolation shelf, or the reverse. The dynamic-isolation job lives on the mechanical equipment isolation page.

When the working stress or the movement demand runs past what a plain pad carries. The escalation runs plain elastomeric (on the order of 800 psi per the vendor TDS) → random-oriented-fiber / cork-rubber (roughly 1500–2000 psi per TDS) → steel-laminated bearings designed per AASHTO LRFD 14.7.6, which carry the most. A laminated bearing is an engineered assembly that belongs to the engineer of record and the bearing designer; H-O’s die-cut and waterjet-cut scope is the plain and fiber-reinforced pads that sit below that line.

Shape factor is the loaded plan area divided by the area free to bulge, and it governs how stiff the pad is in compression. A wide, thin pad (high shape factor) bulges little and carries more stress; a small, thick pad (low shape factor) bulges more, carries less, and accommodates more rotation. That is why a pad is never sized by footprint alone: the same elastomer at the same durometer behaves differently at a different aspect ratio. State the load, the plan, and the thickness together so the check runs against the right shape factor.

Yes — thick pad stock that a steel-rule die will not cut cleanly is waterjet-cut to the plan on the drawing, including holes for anchor bolts and notches at clips. Strips and shim stock are slit or die-cut, and pad-and-shim sets are kitted by joint or by member so the crew sets each bearing from one package, with the material traceability and lot-code TDS records behind every pad.

Outdoors, yes — and the chemistry is chosen for it. Chloroprene (neoprene), the D4014 Type CR elastomer, carries ozone-resistance data per ASTM D1149 on its TDS and is the standard exposed bearing material. Where the pad is a weather-exposed non-bridge setting or leveling pad, solid EPDM is the ozone- and UV-durable step — but never as a D4014 bearing, because the standard covers only Type CR and Type NR. Indoors under set equipment, exposure recedes and creep resistance drives the choice instead.

The member type and the bearing (dead + live) load, the bearing area, the required rotation and movement, the exposure, the governing spec (AASHTO M251 / ASTM D4014 or the equipment setting drawing), the durometer if specified, and the joint drawing — plus quantities for prototype and production. “Recommend the family” is a valid callout, that is what the review is for.