Maximum Span of Prefabricated Beams in Houses
The maximum span of prefabricated beams in houses varies significantly depending on the structural form and purpose. In ordinary buildings, the suitable span for prestressed concrete beams ranges from 16 to 30 meters, while in bridge engineering, the maximum span of prefabricated concrete box girders can reach up to 80 meters. Standard residential projects commonly use prefabricated beams with spans of 4 to 12 meters.
Prestressed Concrete Beams in Ordinary Buildings
In the field of ordinary buildings, prestressed concrete beams significantly enhance crack resistance and stiffness by applying pre-tensioning stress to counteract the compressive stress generated by loads, allowing for larger spans. The suitable span range is typically 16 to 30 meters, suitable for scenarios requiring spatial flexibility, such as large-span factories and commercial complexes. For example, in industrial factories, to meet equipment layout requirements, prefabricated prestressed beams with spans of 20 to 25 meters are often used; in the roof structures of large exhibition centers or stadiums, spans may approach 30 meters to reduce the number of internal support columns and improve space utilization.
Prefabricated Concrete Box Girders in Bridge Engineering
Bridge engineering demands higher spans, and prefabricated concrete box girders, with their large torsional stiffness and good overall integrity, have become the preferred choice for long-span bridges. Currently, their spans have exceeded 60 meters, even reaching 80 meters. For instance, the 80-meter-span prefabricated box girders used in the Hangzhou Bay Cross-Sea Railway Bridge of the Tongsu Jiayong High-Speed Railway achieve a balance between lightweight design and high load-bearing capacity through optimized box girder section design, the use of high-strength concrete, and prestressed systems, setting a benchmark for the span of prefabricated concrete box girders worldwide. Such long-span box girders are mostly used in complex environments like cross-sea and cross-river bridges, reducing the number of piers, lowering construction difficulty, and minimizing the impact on aquatic ecosystems.
Prefabricated Beams in Standard Residential Projects
In standard residential projects, prefabricated beams mainly range from 4 to 12 meters and primarily serve local structures such as floor slabs and balconies. For example, the span of prefabricated beams for floor slabs in ordinary residences is mostly 4 to 6 meters, meeting the needs for residential space division; while balconies or corridors with eaves may use prefabricated beams with spans of 8 to 12 meters, balancing structural safety and construction efficiency. These beams typically adopt non-prestressed or low-prestressed designs to control costs and adapt to the sensitivity of residential buildings to deformation.
