K L Yap Consultants

K L Yap Consultants We carry out structural analyses, design of reinforced concrete, prestressed concrete, steel members and connections.

18/12/2022

Recently I attended a 2-day seminar on advanced features of structural analysis using ETABS. One of the topics touched on was using response spectrum for seismic analysis. It’s a simple process in Singapore, scaling the design response spectrum with the one and only value of peak ground acceleration, and program like ETABS will take care of the rest. I wonder what proportion of seismic engineers are versed in the bases of what the software is doing and therefore what limitations such an approximate analysis has. After all, the basis of modern seismic analysis is ductility, deformation beyond yield point, nonlinearity; but design offices mostly run elastic modal analyses on elastic response spectrum modified by behavior factor to account for reduced force demand due to ductility and force redistribution at plastic hinges. The codes therefore set conditions under which such an analysis can be used.

23/10/2022

Having recently gone through some salient topics regarding earthquake analysis, such as SDOF and MDOF deterministic and stochastic analyses, I can finally set dynamics of structure aside and go on to a refresher on steel connections design. I said refresher because when I first launched into the structural engineering domain, I did a lot of connections design under BS5950. Long before Eurocodes were made mandatory in Singapore, I’ve written spreadsheets and designed based on EC3-1-8. It’s high time to go through the 2 green books by SCI and BCSA once again, cross ref EC1-1-7, EC3-1-8 and get hands dirty on Ram Connection.

Important ideas are detailing to conform to assumed nominal fixity, load paths, standardisation. So it’s great to have a benchmark of bolts, welds, fittings from which to think of variations from standard details. By standard, the green books say M20 Grade 8.8, full-strength fillet welds expressed in terms of web thickness, just to cite 2 examples.

06/06/2022

It’s an eye opener to read material that is outside of my domain, which is predominantly civil engineering. In this case an investor report of Rolls Royce Holdings of June 2022. They’re diversified: Civil aviation, defence, power generation and storage. In targeting net zero carbon emission, research and collaboration into small nuclear reactors , alternative fuels, hybrid, electrification. I come across phrases like mission critical, EFH(Engine Flight Hours), end market, OEM(Original Engine Manufacturer), eVTOL(electric Vertical Take Off and Landing). Concept of efficiency like lengthening engine’s on-wing time, evolving fan blades that last longer at melting temperature, digital twin etc.

Although this book is classified under economics, I’m particularly impressed with the way concepts of efficiency, fairne...
30/05/2022

Although this book is classified under economics, I’m particularly impressed with the way concepts of efficiency, fairness and sustainability have been elucidated by the author. The way the electoral system of the US has been made clear by examples of how legislations may not reflect public opinions is appreciated. Finally the concept of how GDP/GNP do not measure well being or happiness is insightful.

Recently I revisited a book entitled “Stumbling on Happiness” which touches on the concept of realism and idealism; and ...
22/05/2022

Recently I revisited a book entitled “Stumbling on Happiness” which touches on the concept of realism and idealism; and how human beings use their imagination to project the present into the memory of the past, perception of the near future and the far future. It has set me thinking if the often inaccurate imagination has given rise to especially acute torment at a time of successive perfect storms as we are going through now. I choose to be as informed as can be about the happenings in our world, rather than hearing and seeing things that are in line with our preconceptions. So I’m concerned about the likely food crisis, energy crisis, possibility of escalation or diffusion of conflict after the US Congress has approved the USD40b of aid to Ukraine.

Meanwhile, nearer home, shortage of labour, escalating construction costs, wage-price spirals could be sticky for a bit if the global demand stalls as profits fall due to inflation and operating costs.

As far as professional development goes, I’m onto distributed parameter systems after discrete parameter systems. In superposition of mode shapes, orthogonality concepts apply as for the discrete systems, only that integration is used in place of summation by matrix operations.

The eigenproblem is relevant in structural mechanics in the method of superposition in dynamics; and in buckling analysi...
11/05/2022

The eigenproblem is relevant in structural mechanics in the method of superposition in dynamics; and in buckling analysis. In the former, the purpose is to evaluate the mode shapes in undamped free vibration and the natural frequencies in each mode of vibration. In the later, the buckling mode shapes and the critical load factors are evaluated. The mode shapes are the eigenvectors and the square of natural frequencies and critical load factors the eigenvalues. Many methods are available for solving the eigenproblem.

We live in very uncertain times. While some may have clung on to any jobs as they need to put food on the table, and oth...
08/05/2022

We live in very uncertain times. While some may have clung on to any jobs as they need to put food on the table, and others who happened to be in the right industries or have made good strategic investment of their time, it’s perhaps wise to step back and ponder if we’re trying too hard. There’s such a thing as save yourself and fight another day. Throughout the past 2 and a half years, I’ve heard of people who collapsed in the hawker centre, who copped cancers, likely stress related. So while especially those of us who are not doing so well and trying so much to restore the status ante, it’s all the more pertinent to think of the harm we are imparting to our health and the tremendous medical costs should we fall ill.

Just completed a reading on the Rayleigh-Ritz vectors and coordinates method of dynamic response analysis. If you ask wh...
02/05/2022

Just completed a reading on the Rayleigh-Ritz vectors and coordinates method of dynamic response analysis.

If you ask what’s the next thing I’m thinking, it’s the Fed’s seemingly firm conviction in raising the interest rates to tame the raging inflation. Costs of borrowing will go up, debt repayment and debt financing will be much more strenuous. Some businesses may not survived. Already, tech stocks valuations have been discounted in the recent trading sessions. I think of what governments in the US, Europe and China will do to alleviate the slow down in GDP should the interest rates be raised successively to curb the runaway inflation, which is now fueled by the snarls of supply chain due to the embargo and cut off of supply playing out between the Western Allies and Russia; and to the lockdown in various parts of China.

At the last chapter of the history of Cao cao, who managed to suppress the warring factions and dominated China in the b...
17/04/2022

At the last chapter of the history of Cao cao, who managed to suppress the warring factions and dominated China in the beginning of the 3rd century. The takeaway is that history keeps repeating with rises, falls, sufferings and prosperity. Take heart that pandemics and wars come and go in the long tapestry of history.

Thinking about contour integration these couple of days while at the same time running errands at the bank, commissioner...
14/04/2022

Thinking about contour integration these couple of days while at the same time running errands at the bank, commissioner of oaths’. Contour is a path in the complex plane along which the integration of a complex function is to be carried out. It is used in evaluating the expressions involving complex frequencies in dynamic analysis.

What with the end of the conflict in Ukraine nowhere in sight, and the Covid situation in Shanghai still severe; and the...
07/04/2022

What with the end of the conflict in Ukraine nowhere in sight, and the Covid situation in Shanghai still severe; and the Fed’s hawkishness in tackling inflation, perhaps many are inevitably going about like headless chooks, yours truly included. I’m glad that I’m still stealing 2 hours each day, as that’s all that’s sustainable, on the deeper sort of pursuit of knowledge. Past couple of days were spent on the solving of the MDOF equations of motions, particularly on proportional damping matrices; direct solutions of the same equations in the time and frequency domains. It’s a joy to grasp a little bit more whenever a revisit is made to the Dirac delta unit impulse function, unit impulse transfer function, complex-frequency-response transfer functions. I also believe temporisation on such concepts, since they involve basic mathematics symbols and concepts like summation, matrix operations, differentials and integrals, are useful since the insight is transferable to other fields like finance.

Address

Singapore
088702

Opening Hours

Monday 09:00 - 17:00
Tuesday 09:00 - 17:00
Wednesday 09:00 - 17:00
Thursday 09:00 - 17:00
Friday 09:00 - 17:00

Telephone

+6588180538

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