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DYMAT® Structural Bearings

Molded Steel Reinforced Bearings

Design

30 Years Later and Still the Best

DYMAT® molded, steel reinforced bearings are manufactured of high quality neoprene or natural rubber with steel plates inside the elastomer and no steel exposed to the environment. This design has been performing excellently for over 20 years.

Design engineers should specify molded, steel reinforced bearings carefully to eliminate laminated bearings with exposed steel edges or laminated bearings with bonded elastomeric covers, since both have a record of field problem

Features

Versatility

The key feature of molded, steel reinforced bearings is their functionality in a wide array of uses and conditions.

Earthquake Bearing Designs

Custom designs are available with the following features: Structure supported on DYMAT® multi-directional bearings with no internal bearing guiding. Connection between the supports and concrete deck is made with a custom unit that disconnects at maximum design horizontal force. These are fixed and unidirectional connectors. When the horizontal force exceeds the maximum design force, as in an earthquake, large molded steel reinforced bearings support the structure and supply the horizontal returning force due to the shear stiffness of the material. DYMAT® offers a design service to incorporate this system into the structural design.

Vibration & Acoustic Isolation Pads

The selection of vibration and acoustic properties of a pad is a special study and the material compound and exact shape of the pad must be carefully selected. DYMAT® offers the service of proposals of pad designs at no obligation. Special type “U” and “L” pad standards are available with reduced shape factors.

Design, Materials & Testing

Design, Materials & Testing

Elastomeric material meets all AASHTO and MTC specifications Standard Durometer A 55±5 Durometer Maximum dead plus live load 6.89 MPa (1,000 psi) Maximum dead load 4.14 MPa (600 psi)

DCPer AASHTO Specifications

Initial deflection less than 7% between zero and 5.52 MPa (800 psi) Allowable shear deflection ±25% of effective rubber thickness

Per MTC Specifications

Initial deflection less than 4% between 1.38 MPa (200 psi) and 6.89 MPa (1,000 psi) Allowable shear deflection ±50% of effective rubber thickness

Materials

High quality neoprene and natural rubber elastomers are compounded to meet engineering requirements. Standard bearings in the table are compounded to meet current AASHTO and the Canadian MTC current specifications. Custom material specifications can be manufactured

DYMAT® Plain Bearing Pads

Available in all Sizes and Thicknesses

The material is standard AASHTO and MTC neoprene or natural rubber in 50, 55, 60 and 70 Durometer A (±5). DYMAT® will manufacture special material specifications on request.

Stability

The least plan dimension of the bearing must be equal to, or greater than, five times the thickness

Compression - Deflection

The initial deflection due to load should not exceed 6% of the thickness when measured between 200 and 1,000 psi

Abnormal Design Conditions

See Transport and Road Research Laboratory Report 708 (1976), Transport and Road Research Laboratory, Crow Thorne, Berkshire, England

Design Criteria for Non-Standard Bearings

Design engineers should be knowledgeable in all aspects of the bearing design. Reference is made to: Design of Neoprene Bearing Pads, E.I. DuPont Company Natural Rubber in Bridge Bearings, Technical Bulletin No. 7 Natural Rubber Bureau, 19 Buckingham Street, London, W.C.2 Since it is not possible to list all potential bearing sizes required for every structure, DYMAT® offers custom sizing service at no obligation to engineers

Calculation of Shear Stiffness

DYMAT® has tested shear stiffness on the standard bearing. Use the following method. KS = G x L x W per unit length / Et KS = Shear Stiffness G = Shear Modulus L = Length of Pad W = Width of Pad E = Number of Internal Elastomeric Layers t = One Layer of Elastomeric Thickness

Typical Uses

  • DYMAT® has tested shear stiffness on the standard bearing. Use the following method. KS = G x L x W per unit length / Et KS = Shear Stiffness G = Shear Modulus L = Length of Pad W = Width of Pad E = Number of Internal Elastomeric Layers t = One Layer of Elastomeric Thickness
  • Building bearings
  • Vibration pads
  • Acoustic isolation pads
  • Shock absorbers
  • Machinery mounting pads
  • Earthquake bearing design pads

Advantages

  • Lightweight, space saving, simple to install
  • No maintenance required
  • No moving parts. No friction or corrosion
  • Absorb movement of structure
  • Excellent shock absorbing and vibration damping
  • Initial and long term economy
  • Lightweight, space saving, simple to install

Data Sheets

  • Molded Steel Reinforced Bearing

Installation

Pintel Concept

Keeper Plates

Fixed Bearing

Have a question or need more information?

Contact Us
Contact Us
Contact DYMAT® USA:
4101 Smith School Road, Building 3, #300, Austin, TX 78744
Tel: +1 888-958-1229
Email: contact@dymatinc.com
www.dymatinc.com
Contact DYMAT® Europe:
38 Vouliagmenis Ave. & 23 Karaiskaki Str., 166 75 Glyfada, Greece
Tel: +30 210 995 9023
Email: dimitris@dymat.eu
www.dymat.eu