Introduction Our engineering philosophy is to conduct structural analysis and design verifications using a transparent, knowledge-based process. FRAME2D-OP is a MATLAB code created by ALPS Consultants to combine classical plane frame finite element analysis with modern optimization techniques. The objective is simple: automate repetitive structural design iterations while maintaining engineering transparency and control. Unlike commercial software that focuses primarily on an

Adisorn Owatsiriwong, D.Eng. ALPS Consultants 1. Introduction Analysis of seismic-resistant frame structures might require considering shear deformation, i.e., the use of simplified wall/pier elements in global frame analysis (Singh, 2023). Shear-deformable frame elements (Bathe 1996; Bischoff 2002) are also useful for modeling members where shear deformation is not negligible, such as deep beams, short columns, and coupling beams. Integrating the FEM with implicit time int

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 condzensation to reduce the DOF with zero mass, i.e., at rotational dofs. (Adapted from Cimellaro and Marasco (2018)) Guyan Reduction

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

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

by alpsdev When working with 3D structural elements such as beams, frames, or trusses, it is often necessary to define a local coordinate...

When it comes to seismic analysis of buildings, one question often gets overlooked: “Should I include the basement in my seismic model?”...

(please see attached file for matlab example)

Short-period buildings (Low rises) are typically subjected to higher base shear but smaller displacement and very low risk of the P-Delta...

In seismic design, one of the most commonly misunderstood topics is the fundamental period of a building and how it affects base shear...

Eigen : "You're searching the entire modal domain , including irrelevant modes — torsion, out-of-plane wiggles, garbage local...

Adisorn Owatsiriwong, D.Eng. **Introduction** In many engineering applications, mechanical systems are subjected to dynamic loads that...

(Preview page) Cite As: Adisorn Owatsiriwong (2024). Approximated Dynamic Analysis using Ritz's Vectors(https://www.mathworks.com/matlabc...

(Preview page) Cite As Adisorn Owatsiriwong (2024). Reduction of Dynamic Matrices using Static Condensation(https://www.mathworks.com/mat...

(Preview page)

Preview page (A complete paper is attached for download)

A workshop presented by Dr. Amnart Khampanit to undergrad students on wind and seismic loads calculation using ETABS. The presentation...