spændbåndsbjælke

A spændbåndsbjælke, often translated as a tie beam or collar beam in English, is a structural element used in timber framing, particularly in roofs and floors. Its primary function is to resist outward thrusts from rafters or joists and to connect opposing structural members, preventing them from spreading apart. In a roof structure, spændbåndsbjælker are typically placed horizontally across the peak of a roof, connecting opposing rafters. This connection helps to prevent the walls from being pushed outwards by the weight of the roof and the forces of wind and snow. Without a spændbåndsbjælke, a roof without internal support would tend to collapse outwards.

In floor construction, spændbåndsbjælker serve a similar purpose, connecting opposing joists to maintain their spacing and prevent sagging. They are crucial for the stability and integrity of the entire structure, distributing loads and counteracting forces that would otherwise lead to deformation or failure. The size and placement of a spændbåndsbjælke depend on the span of the timbers it supports, the expected loads, and the overall design of the building. They are a fundamental component in traditional timber construction, contributing to the longevity and robustness of many historical buildings. The concept of resisting outward thrust is a core principle in structural engineering, and the spændbåndsbjælke is a simple yet effective application of this principle.