Types of Bracing Systems
The bracing systems are necessary for structures that are subjected to
lateral loads due to earthquakes, wind, etc. They help in minimizing the
lateral deflection of the structure.
We can say that the beams and columns of the framed structure carry
vertical loads while the bracing system carries lateral loads.
Contents
1. Advantages of Bracing systems
2. Types of Bracing Systems
2.1. Horizontal Bracing System
2.2. Vertical Bracing System
Advantages of Bracing
systems
- Under bending loads compression flange of the
main beam tend to buckle horizontally. The Bracing systems resist the
buckling of the main beam.
- The bracing system helps in distributing the
vertical and lateral loads between the main beams.
Types of Bracing
Systems
Majorly Bracing systems are classified as:
- Horizontal
Bracing System
- Vertical
Bracing System
Horizontal Bracing
System
This consists of bracing at each floor in the horizontal planes thus
providing load paths so that the horizontal forces can be transferred to the
planes of vertical bracing.
The horizontal bracing system is too divided into two major types
namely:
- Diaphragms and
- Discrete
triangulated bracing
Some floor systems provide a perfect horizontal diaphragm while others
like precast concrete slabs require specific measures. It can be understood by
the example of steelwork and precast concrete slab as these must be joint
together properly to avoid relative movements.
Discrete triangulated bracing is taken into consideration when the floor
system cannot be used as a horizontal bracing system.
Discrete triangulated bracing
Vertical Bracing System
In vertical planes, bracing between column lines provides load paths
that are used to transfer horizontal forces to ground level. This system aims
to transfer horizontal loads to the foundations and withstand the overall sway
of the structure. These are the bracings placed between two lines of
columns.
It can also be
studied in two types namely:
- Cross-bracing and
- Single
diagonal.
Cross bracing is slenderly withstanding tension forces only and not compression
forces, it also provides necessary lateral stability depending on the direction
of loading.
Unlike Cross bracing, Single diagonal bracing is designed to resist both tension forces and compression forces. In this, diagonal structural members are inserted into rectangular areas of a structural frame which is good for the stabilization of the frame. For fulfilling the requirement of a comparatively efficient system, bracing elements are placed at nearly 45 degrees. This arrangement is strong and compact.
The vertical Bracing system is designed to resist:
- Wind
forces
- Equivalent
horizontal forces
The number of vertical planes required to be installed:
- A
minimum of two vertical planes in each orthogonal direction are provided
so that to avoid disproportionate collapse.
- At
least three vertical bracings are provided so that to generate adequate
resistance in both directions in the plan and against torsion forces around
the vertical axis of the structure.
- A higher number of vertical
planes of bracing will enhance structural stability.
Er. SP. ASWINPALANIAPPAN., M.E., (Strut/.,)., (Ph.D.,)
Structural Engineer
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