The spandrel beam emerges as an important part of frame structures. This article focuses on defining and discussing different aspects of spandrel beams.
What is Spandrel Beam?
In steel or concrete structures, the spandrel beam is the exterior beam that stretches horizontally from one column to another column. These are also known as edge beams.
Spandrel beams are provided on each floor which helps distinguish floor levels in high-rise buildings. These are used to withstand the load of the peripheral walls, in some cases, and also the roof loads of a building because masonry walls generally can not carry self-weight and slab weight entirely.
Load Distribution Method
Spandrel beams are designed to transfer external wall load and slab load from slabs to the outer columns. Then the whole load is passed on to the footings through the columns. In RCC structures, these beams undergo axial compression, torsion, bending moment, and shear stresses simultaneously due to their interaction with the floor beams. Slab load is fundamentally transmitted by torsion from beam to columns. Hence, it creates a complex system of load distribution.
Features of Spandrel Beam
The properties of the Spandrel beam highly depend on the floor beam characteristics. Beams connected to flanged floor beams rather than rectangular floor beams produce enhanced capability of resisting torsional stresses. This consequently increases the ultimate load capacity of the high-rise building. The torsional behavior of the Spandrel beam is a significant feature as slab load is fundamentally transmitted from beam to column by torsion. Therefore, the beam requires additional attention to torsional failure while designing. The latest design code followed for this beam is ACI Committee 318, Building Code Requirements for Structural Concrete and Commentary (ACI 318-19).
The following are the key features of the spandrel beam:
- The spandrel beam is a connection between two beams that span the width of a floor slab.
- The spandrel beam provides resistance to torsional loads and is essential for the stability of high-rise buildings.
- The design of the spandrel beam is critical to ensure the structural integrity of the building.
Types of Spandrel Beam
There are various types of spandrel beams used in building construction. Some of them are:
- Simple beam with rectangular cross-section
- Simple beam with I-section
- Continuous beam with rectangular cross-section
- Continuous beam with I-section
- Plate girder
Uses of Spandrel Beam
Spandrel beams are used in multi-story buildings at each floor level. These are attached to the outer perimeter of floor slabs as a belt to support the floor beams. It also strengthens the connection between the slab and outer columns. On the roofs, the parapets are placed above these beams.
- Spandrel beams are used to support masonry arches and walls.
- Spandrel beams can also be used in trusses and other structures where they act as horizontal members.
- In bridges, spandrel beams are often used to support the deck and roadway.
- In buildings, spandrel beams are often used to support floors and roofs.
- Spandrel beams can also be used in staircases, where they support the steps.
Advantages of Spandrel Beam
The followings are the advantages of spandrel beam:
- Spandrel beams impart extra strength to the outer sides of a multi-story building.
- These beams increase the lateral stiffness of steel and concrete structures. In wide beam-column connections, spandrel beams with both longitudinal and transverse reinforcements are preferred use. This enhances the building’s seismic performance.
- Spandrel beams are used in coupled shear walls to produce sufficient stiffness and ductility against earthquake activities. These also provide support for the external side openings such as windows along with shear walls and lintel.
- These beams are helpful in the construction of parking garages. The spandrel beams at the corners of the garage help in transferring the loads from the upper floors to the lower levels without any issues.
Disadvantages of Spandrel Beam
The followings are the disadvantages of spandrel beam:
- Limited application due to its narrow beam width.
- Spandrel beams can only support a limited weight load.
- May not be strong enough for some applications. As Spandrel beams are located on the exterior of a building, these more often come in contact with moisture than floor beams which results in
- Deterioration or rusting of reinforcement steels.
- Cracking and spalling of concrete.
Therefore, a considerable amount of money is spent on the restoration.
What is the difference between a spandrel beam and a girder beam?
A spandrel beam is a beam that has one end supported on a wall or column and the other end is supported by a beam or girder. A girder beam is a beam that supports itself and does not need another beam or column to support it.
One main difference between a spandrel beam and a girder beam is that girder beams are able to support more weight than spandrel beams. This is because girder beams have a stronger and more rigid structure. Additionally, girder beams are often used in larger construction projects due to their ability to support greater weight.
Another difference between the two beam types is that spandrel beams are often used for decorative purposes. For example, spandrel beams are often used to create arches or other architectural features. Girder beams, on the other hand, are typically only used for functional purposes.
Ultimately, the main difference between a spandrel beam and a girder beam is their respective functions. Spandrel beams are typically used for decorative purposes while girder beams are used for functional purposes.
- McGraw-Hill Dictionary of Scientific & Technical Terms
- Mogbo, N.C.I. (1968). “Torsional behavior of Spandrel beams”. Retrieved from Rice University Library
- Behnam, H., Kuang, J.S., Abdouka, K. (2016). “Behaviour of RC Spandrel beam in exterior wide beam-column connections” Australian Earthquake Engineering Society 2016 Conference, Nov 25-27, Melbourne, Vic
- Salman, R.M.S., Ali, A.A.M. (2015). “Reinforced Concrete Spandrel-Floor Beams Interaction” ISSN(Online): 2319-8753