Engineering Insights

08/28/2026

Calculation notebook for the foundation of street light and billboard

08/26/2026

Useful information ❤️

08/23/2026

08/16/2026

Concrete information ❤️🖤

08/13/2026

Types of Roof Truss Systems: Information with Details

08/06/2026

Only for genius 🥸

07/28/2026

07/26/2026

Dead Load:
Self Weight of Beam: 0.23 x 0.30 x 24 =
1.656KN/m

Finishes: 1.2 KN/m (just an assumption, it can differ based on design specs)
Concrete Fascia: 4 KN/m (also assumed)

A Little Note: Please note that the values I assumed are pretty subjective and can vary quite a bit depending on the design specifications.

For example, if we’re using screed for the beam finishes, the load may range from 0.6 KN/m² to
2.0 KN/m², depending on thickness.

And if we go with tiles (like ceramic or porcelain), it can range from 0.50 to 1.8 KN/m² based on type and thickness, too.

The same applies to the concrete fascia; I compared its weight to a 225mm block with rendering, which weighs about 3.47 KN/m² and I adopted 4 KN/m.

Live Load:
According to EC1 (Actions on Structures), Clause 6.3.4 of BS EN 1991-1-1:2002 – Table 10.6

States that for roofs not accessible except for normal maintenance and repairs the live load ranges from 0.9 to 1.5KN and 0.0 to 1.0 KN/m².

So I opted for 1.0 KN/m.

After calculating the design load as per Eurocode, I ended up with 10.756 KN/m.

With this information, I analyzed the beam to obtain the design parameters (Support Moment, Span Moment, and Reaction Force).

Here’s a step-by-step procedure of how I designed the beam:

Step 1: Calculate the moment of resistance (K) and compare it with the ultimate moment of resistance (Kbal).

Step 2: Determine the Lever Arm factor (La) and limit it to 0.95.

Step 3: Calculate the Lever Arm (Z).

Step 4: Calculate the required area of steel.

Step 5: Check for gradual tension failure of the steel at Ultimate limit state and not sudden brittle failure of the concrete in compression.

This is key for achieving an under-reinforced design instead of an over-reinforced one.

Step 6: Deflection check.

Step 7: Design for shear (stirrups/links)
Just to share my insights on the concept of shear;

When a load is applied, it pushes the beam down while the supports push it up, kind of like a tug-of-war 😂 This creates a sliding movement, particularly at the support zones.

We see more shear there because the movement is more intense compared to the midspan where there’s no support.

This explains why shear force is Maximum at support and almost zero at midspan.

To control/arrest this sliding movement, we provide links/stirrups across the beams, spaced closely near the supports.

They act like binders arresting that upward and downward movement. (Shear)

Step 8: Finally, check for the minimum and maximum area of steel.

07/24/2026

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