Atlas Bearing™ 258
Atlas Bearing™ 258 is a 50 Shore A Neoprene (CR) bearing pad designed to evenly transfer load from beams to supports in bridge bearing and structural applications. It delivers 2250 psi min. tensile strength and 400% min. elongation with a compression set of 35% max. (22 hours @ 212°F). The material meets AASHTO standard specification M251-06 and AASHTO LRFD bridge construction specification Section 18.2, and is rated to -40°F cold temperature per ASTM D2137.
Key Properties
- Durometer / Hardness (Shore A): 50 — ASTM D2240
- Tensile Strength: 2250 min. psi — ASTM D412
- Compression Set, 22 Hours @ 212°F: 35% max. — ASTM D395B
- Elongation: 400% min. — ASTM D412
- Cold Temperature: -40°F — ASTM D2137
Ozone, 100 PPHM, 20% Strain, 100 Hours @ 104°F: No cracks — ASTM D1149
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Material / Substrate | Neoprene (CR) | — |
| Color | Black | — |
| Thickness | 1/4″, 1/2″, 1″ | — |
Mechanical Properties
| Property | Value | Test Method |
| Durometer / Hardness (Shore A) | 50 | ASTM D2240 |
| Tensile Strength | 2250 min. psi | ASTM D412 |
| Elongation | 400% min. | ASTM D412 |
| Compression Set, 22 Hours @ 212°F | 35% max. | ASTM D395B |
Thermal Properties
| Property | Value | Test Method |
| Cold Temperature | -40°F | ASTM D2137 |
Aging Performance — Heat Aging (70 Hours @ 212°F)
| Property | Value | Test Method |
| Durometer / Hardness Change | +15 | ASTM 573 |
| Tensile Change | -15% max | ASTM 573 |
| Elongation Change | -40% max | ASTM 573 |
Environmental Performance
| Property | Value | Test Method |
| Ozone, 100 PPHM, 20% Strain, 100 Hours @ 104°F | No cracks | ASTM D1149 |
Regulatory / Compliance Data
| Property | Value | Test Method |
| AASHTO M251-06, Polyisoprene, Grade 2 | Meets | — |
| AASHTO LRFD Bridge Construction Specification, Section 18.2 | Meets | — |
Compliance
- AASHTO M251-06 (Plain and Laminated Elastomeric Bridge Bearing Pads, Polyisoprene, Grade 2) — Compliant
- AASHTO LRFD Bridge Construction Specification, Section 18.2 — Compliant
- Bridge bearing pads for pre-cast and pre-stressed concrete structural applications requiring AASHTO compliance
- Elastomeric bearing pads for buildings with structural steel beams or steel-reinforced concrete
- Isolation and load distribution pads for industrial machinery and heavy equipment foundations
- Railway tie pads requiring durable neoprene elastomer performance
- Bearing and isolation elements in buildings, arenas, tunnels, and civil infrastructure
Common industries: Bridge and infrastructure construction, structural engineering, civil construction, railway, industrial equipment.
Atlas Bearing™ 258 is the softest and most flexible grade in the Atlas Bearing™ series at 50 Shore A, engineered for bridge bearing and structural applications in pre-cast and pre-stressed concrete, steel-framed buildings, industrial machinery foundations, railway tie pads, and civil infrastructure including arenas, tunnels, and buildings.
Its primary function is to evenly transfer compressive load from structural beams to their supports while accommodating movement and providing shock and vibration isolation. The 400% min. elongation is the highest in the series, reflecting its compliant, movement-accommodating profile.
The material meets AASHTO M251-06 for plain and laminated elastomeric bridge bearing pads (polyisoprene, grade 2) and AASHTO LRFD bridge construction specification Section 18.2. It passes ozone resistance testing at 100 PPHM, 20% strain, 100 hours at 104°F with no cracks per ASTM D1149. Heat aging at 212°F for 70 hours yields hardness change of +15, tensile change of -15% max., and elongation change of -40% max.
Compliant with AASHTO M251-06 and AASHTO LRFD Section 18.2.
What differentiates Atlas Bearing™ 258 from the 60 and 70 Shore A grades in this series?
Atlas Bearing™ 258 is the softest grade in the Atlas Bearing™ series at 50 Shore A, providing the highest elongation (400% min.) and greatest compliance under load. It is the appropriate selection for bridge bearing and structural applications where accommodating the greatest range of structural movement and rotation is the primary design requirement alongside load transfer.
Why is compression set an important consideration for elastomeric bearing pads?
Compression set measures how well an elastomer recovers its original thickness after sustained compression. In a bridge bearing or structural pad, high compression set means the pad permanently flattens under long-term structural load, reducing its ability to accommodate movement and distribute load evenly — potentially compromising structural integrity. Atlas Bearing™ 258 is rated at 35% max. compression set (22 hours @ 212°F per ASTM D395B), consistent with AASHTO requirements for elastomeric bearing pads.
What is the cold temperature rating for Atlas Bearing™ 258?
Atlas Bearing™ 258 is rated to -40°F cold temperature per ASTM D2137, as listed on the TDS.
Is Atlas Bearing™ 258 suitable for bridge and structural infrastructure applications?
Yes. Atlas Bearing™ 258 meets AASHTO standard specification M251-06 for plain and laminated elastomeric bridge bearing pads (polyisoprene, grade 2) and AASHTO LRFD bridge construction specification Section 18.2, as stated on the TDS.
How should Atlas Bearing™ 258 be specified?
Specify grade (Atlas Bearing™ 258), thickness, compliance requirements (AASHTO M251-06 / AASHTO LRFD Section 18.2), dimensional tolerances, and finished format.
