bjelker

Bjelker are structural elements used to support loads in buildings, bridges and other structures. The term is the plural form of bjelke in Norwegian and Danish, referring to horizontal or sloped members that transfer weight to columns or other supports.

They can be made from timber, steel, or reinforced concrete. Timber bjelker are commonly sawn or engineered as glulam; steel bjelker include wide-flange or I-beams; concrete bjelker form part of reinforced concrete constructions. The choice of material depends on factors such as span, load, environmental conditions, and cost.

Common shapes and configurations include rectangular cross-sections for timber beams, and I-, H-, or T-profiles for steel beams. In timber construction, bjelker often support floors and roofs and are spaced with joists or planks; in steel or concrete construction, beams typically carry longer spans and larger loads, with steel frames or concrete slabs forming the structural system. The design of bjelker involves calculating bending moments, shear forces, and deflections to ensure safety and serviceability.

Installation and maintenance are important for performance. Proper end bearings, secure connections using bolts or screws, and correct alignment ensure even load distribution. Timber bjelker require protection against moisture, rot, and insects; steel beams may need coatings to prevent corrosion; reinforced concrete beams require proper curing and control of cracking. Regular inspection helps identify damage or wear that could compromise strength.

The concept of bjelker has been central to construction since ancient times, evolving with engineered wood products and modern steel and concrete technologies. The term remains a general designation for load-bearing beams in Nordic and other European building practices.