Monthly Archives: August 2013

Numerical Integration in Finite Element Analysis

NUMERICAL INTEGRATION Numerical Integration is of prime importance when we deal with Finite Element Analysis especially in case of ISOPARAMETRIC ELEMENTS. Gauss Quadrature formula is the most commonly used Numerical Integration schemes. In this method sampling points are located and weight factors are attached to it. The attached document carry sufficient examples to explain the… Read More »

Response Spectrum Analysis in STAAD explanation Video

Response Spectrum Analysis in STAAD explanation Video Methodology The design lateral shear force at each floor in each mode is computed by STAAD in accordance with the IS: 1893 (Part 1) -2002 (equation 7.8.4.5c and 7.8.4.5d.) Qik = Ak*fik*Pk*Wi STAAD utilizes the following procedure to generate the lateral seismic loads. User provides the value for… Read More »

Principle of Virtual Work and Minimum Potential Energy (P.E.)

Principle of Virtual Work and Minimum Potential Energy (P.E.)   Introduction: The Total Potential Energy is nothing but the energy due to Strain Energy (internal work done) and Work potential of a force (external work done).   Theorem of P.E.: Of all the displacements satisfying given Boundary conditions and Equilibrium conditions, the actual displacement is… Read More »

Shape Functions or Interpolation Functions

Shape Functions or Interpolation Functions In FEA we discretize the solution region into finite elements. To conduct the analysis we assume a displacement model to approximately indicate the variations of the displacement within the element. The polynomial chosen to interpolate the field variables over the element are called shape functions. Denoted by[N], they establish the… Read More »

Classification of Earthquakes

Classification of Earthquakes BASED ON LOCATION: Interplate Intraplate An interplate earthquake is one that occurs at a plate boundary An intraplate earthquake is an earthquake that occurs in the interior of a tectonic plate Recurrence time is less Recurrence time is longer Interplate Earthquakes are recognized at surface Intraplate earthquakes are rarely recognized at the surface. This is because the faults are… Read More »

Basics aspects in Finite Element Method (FEM)

FINITE ELEMENT METHOD (FEM) Introduction: Finite Element Method (FEM) is nothing but a numerical technique to get the approximate solution to the boundary value problems consisting of a partial differential equation and the boundary conditions. The Finite element Method converts these typical equations into a set of algebraic equations which are easy to solve. Basic… Read More »

Design of Square Footing with Axial Loading (Solved Example)

Design of Square Footings Footing is the lower end of a column, pillar or wall which is enlarged with projecting courses so as to distribute the load. Below explained design of a concrete footing. See the attached document below for detailed explanation of design of square footing. Problem Design a square footing for a square… Read More »

State of Stress – Stress Tensor

State of stress at a Point (Stress Tensor) Consider a three dimensional body in equilibrium under the action of a set of external forces P1,P2,P3.. , the stresses developed in different planes vary. To study the magnitude of these forces at any point let the body be divided into 2 parts A&B by a cross… Read More »

SOFT STOREY EFFECT DURING EARTHQUAKE

SOFT STOREY EFFECT In shaking a building, an earthquake ground motion will search for every structural weakness. These weaknesses are usually created by sharp changes in stiffness, strength and/or ductility, and the effects of these weaknesses are accentuated by poor distribution of reactive masses. Severe structural damage suffered by several modern buildings during recent earthquakes… Read More »