tailieunhanh - Bearings

Bearings Introduction . Types of Bearings Sliding Bearings • Rocker and Pin Bearings • Roller Bearings • Elastomeric Bearings • Curved Bearings • Pot Bearings • Disk Bearings Johnny Feng J. Muller International, Inc. Selection of Bearings Determination of Functional Requirements • Evaluation of Bearings • Preliminary Bearing Design Hong Chen J. Muller International, Inc. Design of Elastomeric Bearings Design Procedure • Design Example Introduction Bearings are structural devices positioned between the bridge superstructure and the substructure. Their principal functions are as follows: 1. To transmit loads from the superstructure to the substructure, and 2. To accommodate relative movements between the superstructure and the substructure | Feng J. Chen H. Bearings. Bridge Engineering Handbook. Ed. Wai-Fah Chen and Lian Duan Boca Raton CRC Press 2000 Section III Substructure Design 2000 by CRC Press LLC 26 Bearings Johnny Feng J. Muller International Inc. Hong Chen J. Muller International Inc. Introduction Types of Bearings Sliding Bearings Rocker and Pin Bearings Roller Bearings Elastomeric Bearings Curved Bearings Pot Bearings Disk Bearings Selection of Bearings Determination of Functional Requirements Evaluation of Bearings Preliminary Bearing Design Design of Elastomeric Bearings Design Procedure Design Example Introduction Bearings are structural devices positioned between the bridge superstructure and the substructure. Their principal functions are as follows 1. To transmit loads from the superstructure to the substructure and 2. To accommodate relative movements between the superstructure and the substructure. The forces applied to a bridge bearing mainly include superstructure self-weight traffic loads wind loads and earthquake loads. Movements in bearings include translations and rotations. Creep shrinkage and temperature effects are the most common causes of the translational movements which can occur in both transverse and longitudinal directions. Traffic loading construction tolerances and uneven settlement of the foundation are the common causes of the rotations. Usually a bearing is connected to the superstructure through the use of a steel sole plate and rests on the substructure through a steel masonry plate. The sole plate distributes the concentrated bearing reactions to the superstructure. The masonry plate distributes the reactions to the substructure. The connections between the sole plate and the superstructure for steel girders are by bolting or welding. For concrete girders the sole plate is embedded into the concrete with anchor studs. The masonry plate is typically connected to the substructure with anchor bolts. Types of Bearings Bearings may be