Grillage foundations play a crucial role in supporting heavy structures like columns, piers, or scaffolds. These foundations, designed to handle substantial loads, distribute weight across a broader area. They are particularly suitable for areas with low soil bearing capacity, eliminating the need for extensive excavations. The depth of a grillage foundation typically ranges from 1000 mm to 1500 mm.
The key components of a grillage foundation include grillage beams, spacing (spandrel) beams, and foundation bolts.
Grillage Beams : These beams, made of steel or wood, form a robust base by being bolted together.
Spacing or Spandrel Beams : Positioned perpendicularly to the grillage beams, these beams provide additional lateral support.
Foundation Bolts : Used to attach the grillage beams to the underlying footing, which can be concrete or steel-reinforced concrete.
While commonly used in commercial construction like office buildings and retail stores, grillage foundations can also be employed in residential construction.
Grillage foundations come in various materials, each suited to specific structural needs.
Timber Grillage Foundation : Constructed with wooden planks, timber grillage foundations are effective in low-bearing capacity soil. The planks, typically 8”-12” wide and 2”-3” thick, are arranged perpendicular to each other, creating a sturdy grid. Bolts secure the layers, and concrete fills the gaps.
Steel Grillage Foundation : Similar to timber foundations, steel grillage foundations utilize MS I-beams. These beams, arranged parallelly, are welded or bolted together, forming a grid. A concrete cover protects the steel from rust.
Reinforced Concrete Grillage Foundation : Made of reinforced concrete, this foundation type leverages advancements in concrete technology. Available in precast or cast-in-situ options, it provides a modern alternative to traditional materials.
Historically used since Roman times, grillage foundations offer benefits like cost-effectiveness, rapid construction, and suitability for projects requiring an early start.
Building Your Grillage Foundation
Let’s break down the process into two parts: Design and Construction.
Design of Grillage Foundation
Construction of Grillage Foundation
While grillage foundations offer advantages like even load distribution, cost-effectiveness, and ease of construction, they may not be suitable for all scenarios. Careful consideration of factors like soil strength and building height is essential. Professional assistance during the design phase ensures a structurally sound foundation.
