MLM Engineering

22/11/2025

𝐔𝐧𝐝𝐞𝐫𝐬𝐭𝐚𝐧𝐝𝐢𝐧𝐠 𝐏𝐫𝐨𝐛𝐚𝐛𝐢𝐥𝐢𝐭𝐲 𝐨𝐟 𝐄𝐱𝐜𝐞𝐞𝐝𝐚𝐧𝐜𝐞

According to Section 208.5.3.2 of the National Structural Code of the Philippines (NSCP) 2015, the 𝐃𝐞𝐬𝐢𝐠𝐧 𝐁𝐚𝐬𝐢𝐬 𝐄𝐚𝐫𝐭𝐡𝐪𝐮𝐚𝐤𝐞 (𝐃𝐁𝐄) is “The ground motion representation shall, as a minimum, be one having a 10% probability of being exceeded in 50 years.”

What does it mean?

When designing a building, Structural Engineers consider the possibility of a powerful earthquake occurring during the building's lifetime. The 𝐩𝐫𝐨𝐛𝐚𝐛𝐢𝐥𝐢𝐭𝐲 𝐨𝐟 𝐞𝐱𝐜𝐞𝐞𝐝𝐚𝐧𝐜𝐞, which is simply the likelihood that an earthquake stronger than a particular level could occur within a number of years, is one way we accomplish this. For instance, if there is a 10% chance in 50 years, it indicates that there is a small but likely chance that shaking stronger than that level will occur during the next 50 years. In order to ensure that buildings remain secure and standing even when the ground shakes, we use this as the earthquake strength level when designing structures.

19/11/2025

𝐓𝐡𝐞 𝐃𝐚𝐧𝐠𝐞𝐫 𝐨𝐟 𝐍𝐨𝐧-𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐞𝐝 𝐇𝐨𝐮𝐬𝐞𝐬

This is one of the most misunderstood concepts in structural design, especially among non-technical individuals. So allow me to clarify.

To those trying to save money when building a house: 𝐲𝐨𝐮 𝐦𝐚𝐲 𝐜𝐮𝐭 𝐜𝐨𝐬𝐭𝐬 𝐚𝐧𝐲𝐰𝐡𝐞𝐫𝐞 𝐞𝐥𝐬𝐞, 𝐛𝐮𝐭 𝐍𝐄𝐕𝐄𝐑 𝐨𝐧 𝐭𝐡𝐞 𝐬𝐭𝐫𝐮𝐜𝐭𝐮𝐫𝐚𝐥 𝐝𝐞𝐬𝐢𝐠𝐧.

In many non-engineered houses (meaning structures built without engineering calculations or without consulting a structural engineer), the amount of steel reinforcement in columns and beams is often guessed based only on intuition or past experience. Even the concrete mix is usually poor, with excessive water that significantly weakens its strength.
The usual reasoning of those who build this way is
“𝐌𝐚𝐫𝐚𝐦𝐢 𝐧𝐚 𝐚𝐤𝐨 𝐧𝐚𝐠𝐚𝐰𝐚𝐧𝐠 𝐠𝐚𝐧𝐲𝐚𝐧 𝐡𝐚𝐧𝐠𝐠𝐚𝐧𝐠 𝐧𝐠𝐚𝐲𝐨𝐧 𝐧𝐚𝐤𝐚𝐭𝐚𝐲𝐨 𝐩𝐚 𝐧𝐚𝐦𝐚𝐧.”
While this may be true, the structure is not necessarily strong; it is only strong enough to carry everyday service loads, the regular loads a building carries throughout its lifetime.

But here’s the 𝐁𝐈𝐆 𝐐𝐔𝐄𝐒𝐓𝐈𝐎𝐍:
Will it still be enough when the house is subjected to strong earthquakes or high winds, hazards our country is highly prone to?
Remember: these extreme events do not happen often within the lifetime of a house. Strong earthquakes can occur only once in decades or even hundreds of years.
That is why many non-engineered houses manage to stand for a long time; they simply haven’t been tested yet by a major earthquake.
But what if a strong earthquake hits during the lifetime of your home?
𝐖𝐢𝐥𝐥 𝐲𝐨𝐮 𝐟𝐞𝐞𝐥 𝐬𝐚𝐟𝐞 𝐤𝐧𝐨𝐰𝐢𝐧𝐠 𝐲𝐨𝐮𝐫 𝐡𝐨𝐮𝐬𝐞 𝐰𝐚𝐬 𝐧𝐨𝐭 𝐩𝐫𝐨𝐩𝐞𝐫𝐥𝐲 𝐞𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐞𝐝?
Past earthquakes in our country have already taught us painful lessons.
Many houses and buildings that looked sturdy from the outside actually had hidden structural weaknesses insufficient to resist strong ground shaking.
𝐓𝐡𝐞 𝐫𝐞𝐬𝐮𝐥𝐭? 𝐋𝐨𝐬𝐬 𝐨𝐟 𝐥𝐢𝐟𝐞 𝐚𝐧𝐝 𝐥𝐨𝐬𝐬 𝐨𝐟 𝐩𝐫𝐨𝐩𝐞𝐫𝐭𝐲.
We must learn from the past.
Hiring or consulting a structural engineer may seem expensive, but it is nothing compared to the cost of damage, destruction, or even the loss of life if your home cannot withstand natural hazards.
𝐘𝐨𝐮𝐫 𝐡𝐨𝐦𝐞 𝐬𝐡𝐨𝐮𝐥𝐝 𝐩𝐫𝐨𝐭𝐞𝐜𝐭 𝐲𝐨𝐮, 𝐧𝐨𝐭 𝐩𝐮𝐭 𝐲𝐨𝐮 𝐚𝐭 𝐫𝐢𝐬𝐤.

Image: CTTO

18/11/2025

I saw my old book in dynamics back in college and was surprised that the topics in structural dynamics we are taught in the graduate school are actually here in this book especially about vibrations. Hanggang particle motion lang ata naabot namin sa dynamics🤣 during our undergrad. It is not given much emphasis compared to statics. But this topic is very important in understanding vibration behavior for structural systems especially in seismic analysis (i.e.,single degree of freedom(sdof) and multi degree of freedom(mdof) systems, vibration analysis, response spectrum analysis).

18/11/2025

ASD/WSD Notes

18/11/2025

17/11/2025

Our work as civil engineers involves much more than just entering data into equations. Anyone can learn an equation by heart, but what makes us unique is knowing why it works, when to apply it, and what it means in real life. Every formula has a backstory that explains how forces move through a beam, how the ground moves beneath a foundation, or how a structure succeeds or fails.

We become true engineers and cease being calculators when we commit these ideas to memory. We acquire the wisdom to make life-saving decisions, the confidence to design safely, and the intuition to see issues before they arise.

Books contain formulas. But we all possess understanding.

03/11/2025

𝐓𝐡𝐢𝐬 𝐢𝐬 𝐨𝐧𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐦𝐨𝐬𝐭 𝐢𝐦𝐩𝐨𝐫𝐭𝐚𝐧𝐭 𝐠𝐫𝐚𝐩𝐡𝐬 𝐢𝐧 𝐬𝐭𝐞𝐞𝐥 𝐝𝐞𝐬𝐢𝐠𝐧, 𝐞𝐬𝐩𝐞𝐜𝐢𝐚𝐥𝐥𝐲 𝐰𝐡𝐞𝐧 𝐝𝐞𝐬𝐢𝐠𝐧𝐢𝐧𝐠 𝐛𝐞𝐚𝐦𝐬 𝐟𝐨𝐫 𝐟𝐥𝐞𝐱𝐮𝐫𝐞, 𝐚𝐧𝐝 𝐡𝐞𝐫𝐞’𝐬 𝐰𝐡𝐲:

Imagine you are holding a steel beam, strong and proud, bending under a load. Now, if you hold it very close between your hands, with not much length left unbraced, it can bend beautifully and reach its full strength, which we call the plastic moment, Mp. Nothing fancy happens; it just yields smoothly. That’s the flat part of the graph no instability, pure strength.

But as you let the beam get longer between braces, something interesting starts to happen. The top fl**ge, which is in compression, begins to wiggle sideways a little when you push too hard. It’s not collapsing yet, just losing some of its nerve. The beam still bends, but it also twists, and this twisting steals some of its strength. This is the inelastic lateral-torsional buckling region between Lp and Lr.

Now, if you stretch that unbraced length even farther, the beam can’t even reach its yield point before it buckles sideways. It fails elastically, just like a ruler that suddenly snaps out of line when you press on it. That’s the elastic LTB region, where the strength drops off fast.

So, what the graph tells us is simple but profound: A beam’s strength doesn’t just depend on its material or shape; it depends on how free it is to move. Give it enough support, and it’s a hero; leave it alone for too long, and it twists out of the game.

References:
1. Segui, W. T. (2018). Steel Design
2. ANSI-AISC 360-16 Specification for Structural Steel Buildings

30/10/2025

ATTENTION TO ALL PICE STUDENT CHAPTER MEMBERS!

The Registration for the upcoming 32nd Bridge Building Competition to be held this 25 November as a part of the 24th National Civil Engineering Students' Conference at the Quezon City Meeting, Incentives, Conferences and Exhibitions (M.I.C.E.) Center, Parking lot, Diliman, Quezon City, 1101 Metro Manila.

Join us for a day filled with learning, and fun activities as we work together towards "Empowering Membership, Promoting Specialization: Building a Stronger PICE for the Preferred Future”.

For inquiries about your chapter membership status, please email us at [email protected].

Registration Link:
https://tinyurl.com/32ndBridgeBuilding

Entry Form:
https://tinyurl.com/32ndBridgeBuildingEntryForm

PICE 24th Students' Conference Website
https://tinyurl.com/24thNCESCC