Understanding Fixed Plate Bearings and Their Span Suitability

Fixed plate bearings are a type of structural bearing used in construction, commonly in bridges and buildings. Their primary function is to transmit vertical loads while preventing movement in any direction (translational and rotational). They are considered 'fixed' because they do not allow for expansion or contraction movement.

The choice of bearing type depends on various factors, including the magnitude of loads, the span of the structure, and the expected movements (expansion, contraction, rotation). Different bearing types are suitable for different span lengths and conditions.

Fixed plate bearings are relatively simple in construction and are generally used for smaller spans where the expansion and contraction movements due to temperature changes, creep, and shrinkage are minimal and can be accommodated by the rigidity of the structure or other means. For larger spans, more sophisticated bearing types like roller, rocker, or elastomeric bearings are required to accommodate larger movements.

Based on typical civil engineering practice and design guidelines, fixed plate bearings are considered suitable for structures with spans up to a certain limit. This limit ensures that the structural movements at the support are within acceptable ranges for this type of fixed connection.

Considering the common applications and limitations of fixed plate bearings, they are typically used for spans not exceeding a specific length.

Let's look at the options provided:

• less than 4 m
• 22 m
• 12 m
• 13 m

While fixed plate bearings can certainly be used for very small spans (like less than 4 m), the question asks for the span limit up to which they are suitable. Spans like 22 m or 13 m are generally considered large enough to require bearing types that can accommodate significant movement, making fixed plate bearings typically unsuitable.

The span limit up to which fixed plate bearings are commonly used is around 12 meters. Beyond this span, the structural movements usually necessitate the use of bearings that permit translation.

Therefore, fixed plate bearings are suitable for spans up to approximately 12 m.