ENG215: Beam Design, Construction, and Testing Practical Report

This practical assignment focuses on the design, construction, and testing of beams using balsa wood. The introduction highlights the goal of understanding different beam structures and their real-world applications. The aim is to determine the strongest beam by observing the failure points of various designs under load. The assignment details the materials used (balsa wood, super glue, and cutters) and the construction process, emphasizing the creation of beams with different designs, each spanning 550mm. The working principle of beams, based on the concept of moments and shear forces, is explained, including how factors like material strength and cross-sectional depth affect load-bearing capacity. The discussion section explores various beam types, including precast concrete, deep beams, pre-stressed concrete, tapered, cast in-situ, static determinate and indeterminate, curved, L-shaped, T-shaped, straight, steel, composite, timber, rectangular, fixed, concrete reinforced, simply supported, continuous, and cantilever beams. The document provides a comprehensive overview of beam design and structural behavior, with references to relevant literature.

Practical Beam 20 March 2020
Content
Introduction……………………………………………………………………………………
…………2
Aim……………………………………………………………………………………………
………………2
Material
Used……………………………………………………………………………………………2
Design and
Construction……………………………………………………………………………2
Working
Principle………………………………………………………………………………………2
Observation and
Discussion………………………………………………………………………3
Conclusion………………………………………………………………………………………
…………3
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Practical Beam 20 March 2020
Introduction
This beam practical introduces the principles of building beams with some different
structures and designs so that we will get to know about some of the best design in the real
world.
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Practical Beam 20 March 2020
Aim
The main aim of this practice is to remark the failure of different beams and determine the
strongest beam from all those constructed beams. Basically, we checked the weight holding
capacity of every beam by putting a load until the beam failed. By doing this we got fine
design at the end.
Material Used
 Balsa wood (1.55mm x 70 mm x 915mm)
 Super Glue
 Cutter
Design and Construction
With the Balsa wood (1.55mm x 70 mm x 915mm) we had to make beams with the different
design and structures. The concept of making this beam was to come with different ideas so
that we can differently design with different dimensions. Each beam was built longer than
550 mm so that beam would span on 550mm and it was in rectangular cross-section and after
a week it was tested to carry the maximum possible load.
Working principle
A beam works on the principle of moments. Beams hold the load by bending only. Due to
moment, it causes an internal shear force that passes on the same force on beam support.
Shear forces develop diagonal tensile and compressive stress.
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Practical Beam 20 March 2020
Since balsa wood has better tensile strength than compressive strength so strain distribution
will be equal to stress distribution.
One method is to make a strong beam by using strong material. Alternatively, its strength
depends on the moment of resistance:
M=kbh²σmax (for rectangular cross-section beams)
In the above-mentioned equation, the moment varies directly with the width of cross-section
and with the square of the depth. So, by increasing the depth of a given cross-section beam,
we can make strong beams which can carry a larger load.
Discussion
The beam structures are as follows:
Precast concrete beam- this type of beam is of high quality and is usually built in a number of
cross-sectional shapes such as T-beam as illustrated below:
Figure: Structure of the precast concrete beam.
Deep beams- this type of beam has large depths with the load usually pulled by the force of
compression. The structure is shown below:
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Practical Beam 20 March 2020
Figure: Structure of a deep beam.
Pre-stressed concrete beams- these are made by putting pressure on strands before applying
loads on them (Attari et al, 2012). A sample diagram is as follows:
Figure: Structure of the pre-stressed concrete beam
Tapered beam- this type of beam has its cross-sections tapered. The diagram is as follows:
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Practical Beam 20 March 2020
Figure: Structure of a tapered beam
Cast in-situ beams- are made by fixing forms then adding freshly prepared concrete and left
for some time to dry. The figure is as shown below;
Figure: An illustration of a cast-in-situ beam
Static indeterminate beam- this type of beam does not have adequate equilibrium to withstand
pressure as illustrated n the figure below;
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Practical Beam 20 March 2020
Figure: Illustration of static indeterminate beam
Static determinate beam- this type of beam has enough equilibrium which is able to withstand
pressure as illustrated below;
Figure: Illustration of a static determinate beam
Curved beams- this type of beam has a curved cross-section normally used in building
circular structures. The figure is shown below;
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Practical Beam 20 March 2020
Figure: An illustration of a curved beam
L-shaped beam- this is constructed using a large block of stone together with concrete slabs
around the building.
T-shaped beam- beams of this kind are usually constructed using large stone blocks and
strengthened using concrete slabs (Mechtcherine, 2013). The diagram is as shown below;
Figure: An illustration of a T-shaped beam
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Practical Beam 20 March 2020
Straight beams- these are the most commonly used beams. They are constructed using
straight bars as illustrated in the diagram below;
Figure: An illustration of a straight beam
Steel beam- this kind of beam is usually constructed using steel. They are normally meant for
several purposes. An illustration of a steel beam is shown below;
Figure: An illustration of a steel beam
Composite beams- this kind beam is constructed using a number of materials which may
include concrete and steel. A sample composite beam is shown below;
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Practical Beam 20 March 2020
Figure: An illustration of a composite beam
Timber beam- this kind of beam was commonly utilised in the past however, their uses have
reduced currently. It was made using timber or logs of wood. An illustration of a timber beam
is shown below;
Figure: A timber beam
Rectangular beams- this type of beam is commonly used in reinforced concrete structures and
some buildings as illustrated below;
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Practical Beam 20 March 2020
Figure: An illustration of a rectangular beam
Fixed beams- this kind of beam is fitted at both ends and is, therefore, effectively able to
evade rotation (Awad et al, 2012). An illustration of a fixed beam is shown below;
Figure: An illustration of fixed beam
Concrete reinforced beam- this kind of beam are constructed using concrete together with
other reinforcements. This is illustrated below;
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Practical Beam 20 March 2020
Figure: An illustration of concrete reinforced below
Simply supported beams- these are the easiest to construct. They have a roller and pinned
support at either end are therefore able to rotate freely and able to sustain bending and
shearing as illustrated below;
Figure: An illustration of simply supported beams
Continuous beam- this kind of beam has several support systems along its cross-section as
shown below;
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