Retaining walls are fundamental in geotechnical and structural engineering, yet their design often involves conservative assumptions that...

Adisorn Owatsiriwong, D.Eng. ALPS Consultants Introduction An underground water tank’s wall is a 2D structure that requires detailed analysis using design charts or sophisticated FEM modeling, e.g., SAP2000. This time-consuming process requires a structural engineer to model the tank geometry and provide triangular load definitions to the model. In this project, we use the Reisner-Mindlin plate element (Bathe, 1996; Bishoff, 2002) to develop a handy FEM tool for water tank

Dynamic analysis of 3D building frames is computationally demanding, especially for multi-story and multi-bay frames. By applying Guyon reduction and rigid constraints, the analysis is highly efficient. Reduction Workflow Full 3D frame DOFs (As Static Analysis) → Guyan condensation to translational DOFs (Lateral mass only) → rigid diaphragm transformation → 3 DOF per floor Stage Main operation Resulting coordinates Full model Assemble K and M using all frame DOFs Nodal t

Introduction Solving a dynamic system requires several time steps and is computationally demanding. The bending moment frame (Fig. 1a), while most common for static analysis, is inefficient for dynamic analysis, particularly for seismic analysis and structural design. Guyan (1965) proposed the reduction technique as an extension to static condensation to reduce the DOF with zero mass, i.e., at rotational dofs. (Adapted from Cimellaro and Marasco (2018)) Guyan Reduction B

Introduction Several time-integration methods for the dynamic response of structures subjected to general time-dependent loading are available. They are classified into 3 main methods: 1. Duhamel's integral (Superposition of impulse) Fourier Series & Fourier Integral (Superposition of the global sine and cosine waves) Direct time integration Duhamel's Integral The Duhamel integral transforms the continuous load function into a sequence of discrete impulses. Then the respo

A technical blog on automated reinforced concrete drilled pier design using strain compatibility and interaction diagram checking Introduction Drilled piers are commonly used as deep foundations for buildings, bridges, industrial structures, retaining systems, and heavy equipment foundations. In many practical projects, drilled piers are subjected not only to axial compression but also to bending moment from lateral loads, column eccentricity, seismic effects, wind, or constr

Nonlinear dynamic analysis plays an important role in seismic performance evaluation of structures. The solution of nonlinear dynamic can be solved by using Newmarks's method. This article provides a 1-DOF cookbook for review purposes and to provide basic knowledge for multi-DOF problems. The algorithm consists of Newmark loop and Newton loop as Time Integration (Newmark) └── for each time step └── Newton Iteration └── Stress Return Mapping

Most swarm intelligence algorithms allow parallelization when computing the objective function. Each particle can be assigned to each worker to call the solver and return the individual objective value. The algorithm can be explained: MATLAB parfor function [x,f] = jaya_parallel(x,f,lb,ub,nPop,nVar,maxIt) for it = 1:maxIt % --- Step 1: find best/worst [f_best, idx_best] = min(f); [f_worst, idx_worst] = max(f); x_best = x(idx_best,:); x_worst = x(idx_worst,:); newx = z

Adisorn Owatsirwong, D.Eng. This equivalent nodal force is opposite to Fixed-end reactions and written in the element force calculation as follows. {Fe} = [ke]{u} - {q} {q} = Equivalent nodal force When assembling the element stiffness, those {q} are summed into the global load vector {F}, i.e. {F} + {Q}= [K]{u} [F] = Nodal applied load {Q} = Sum of equivalent nodal load vector [K] = The global stiffness of the structure MATLAB Code (case qe = q) function feq = eqv_load_dro

When writing scientific codes or optimization solvers like PT-OP, you will quickly face one design decision: Should this piece of logic be written as a subroutine, a function, or wrapped in a module? At first, these terms can seem similar — but understanding their roles is the foundation of clean, safe, and efficient Fortran programming. 🔹 1. Subroutine vs Function Type Purpose Returns a value? Called by Subroutine Performs an action (procedure) ❌ No call my_sub(a, b, c) Fun

When developing large, performance-oriented programs—especially in FEM and optimization—it’s critical to keep your Fortran code modular, readable, and safe. Below are four golden rules for managing subroutines and functions effectively in modern Fortran (Fortran 90+). 🔹1. Use Modules for Organization and Reusability A module is like a toolbox — it groups related variables, constants, and functions in one unit, and lets other parts of the program access them using the us

Shear reinforcement in a concrete beam is required when the shear strength of concrete alone is inadequate to carry the vertical shear from external loads. ACI 318 stipulates the general equation for computing the vertical shear strength of a concrete beam with inclined stirrups as follows. Vs = As*fy*d/s*(sin(a) + cos(a)) where a = horizontal angle of the inclined stirrup It's first astonishing to see the term cos(a) for the shear strength of the stirrup, which should only b

Keywords: Sheet-pile wall · Retaining wall · Metaheuristic optimization · Cost minimization · Reliability-based design · Multiobjective...

Artificial Intelligence is being advanced to the point where engineering design can be automated to an unprecedented extent. Within a...

1. Inspiration: Nature’s Hierarchy and Intelligence Greywolf's Hunting Mechanism (source: S. Mirjalili) The Grey Wolf Optimizer (GWO) ,...

Adisorn O. | ALPS Consultants 📌 The Problem with Traditional Methods Anchored sheet pile (SP) walls are typically designed using...

Retaining walls remain a core element in geotechnical engineering, but their design has often relied on manual iterations, conservative...

Background Proposed by Rashedi et al. in 2009 ( “GSA: A Gravitational Search Algorithm” ). Belongs to the family of physics-inspired...