Response Spectrum of El Centro Ground Motion ver 2

 NSCP requires dynamic analysis for irregular structures and structural engineer should learn the concept of response spectra and how it is derived by Numerical Methods. This video explains the generation of response spectra using Central Difference Method and how base shear formulas were derived using the concept of Response spectra.

Basic Matrix Structural Analysis

 In this lecture, I showed how to analyze an indeterminate truss structure using Matrix Analysis.

My primary reference here are Kassimali and Mcguire.

Further in the lecture, I used SMATH to automate the process of analyzing the structure to show that STAAD and ETABS are simply automating the generation of Structure Stiffness Matrix.

Here, the lecture is about Sway Frame Analysis. We can approximate the analysis of multistory building using just Beam stiffness matrix by assuming no axial deformation will be present thus no need to use the axial part of stiffness matrix.

NSCP 2015 2nd Printing

ASEP recently introduced the 2nd printing of NSCP 2015. Thanks for the webinar they conducted last month because many structural engineers were made aware of the changes in the 2nd printing. Most important of this is shown below:

BEAMS FOR SPECIAL MOMENT FRAMES
Remember that in almost all cases, the framing system we used in most part of Philippines is SMRF since we are an earthquake prone region. In the 2nd printing, NSCP now allowed 200mm minimum girder dimension from the previously 250mm. This has a lot of cost implications. The previous 250mm made many architects bit angry especially when youre project is a typical residential one. With this new provision, for sure it will be a great relief. However, lets not forget that implementation of this minimum dimension should be carefully observed since many recent earthquakes prove too strong for very small beam and column dimensions.

COLUMNS FOR SPECIAL MOMENT FRAMES
Remember that in almost all cases, the framing system we used in most part of Philippines is SMRF since we are an earthquake prone region. In the 2nd printing, NSCP now allowed 250mm minimum column dimension from the previously 300mm. This has a lot of cost implications. The previous 300mm made many architects bit angry especially when your project is a typical residential one. With this new provision, for sure it will be a great relief. However, lets not forget that implementation of this minimum dimension should be carefully observed since many recent earthquakes prove too strong for very small beam and column dimensions.

Many are not aware that our design base shear from earthquake is a reduce base shear because NSCP allowed our structure or expect it to behave INELASTICALLY during earthquake if you follow the seismic detailing NSCP recommends.  For discussion of this detailing, refer to the videos below:

Girder Design and Detailing

Column Design and Detailing

Finite Element Analysis and Design of Mat Foundation using STAAD

I created another ebook(draft copy) for design and analysis of mat foundation using Finite Element Modeling and Analysis in STAAD. Design is made using SMATH software which is a free one.

Download here.

LOWRISE

STAAD FILES

Response Spectrum Using El centro Ground Motion

All structural design building codes have design response spectra. In this video you will learn how this was made using just excel. However, in the code, ductility factor is incorporated such that base shear from earthquake is reduced. This video however shows pseudo acceleration response spectra which is required prior to doing the inelastic design response spectra. Download excel here.

Response spectrum generation

staad files for practice

staad files for use in 8 storey training