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

SEISMIC DESIGN MANUAL

NSCP code is patterned from UBC 1997 of USA. SEAOC is an organization of structural engineers in California USA that is similar to ASEP. This manual is made by SEAOC who is in charge also of seismic provisions in UBC 1997. Reading this and its commentary will help you learn Seismic Design intent of NSCP.

Seismic Design Manual

EBOOK on Seismic Analysis and Design of RC Building

I created an ebook for beginners wanting to learn Seismic Analysis and Design of RC Building Using STAAD and Spreadsheet.

Feel free to download draft copy of this..just send a message. FREE EBOOK

DESIGN OFSTRUCTURE USING STAAD AND SPREADSHEET

Design and analysis of structure is normally done in the following procedure:

1. Setting up Design criteria
2. Modeling of structure in STAAD
3. Adding loads in structure
4. Design of Gravity Members
1. One way slab
2. Two way slab
3. Intermediate Beam
5. Design of Seismic resisting Members
1. Girder
2. Column
6. Design of Foundation
7. Compiling the result in a structural design report for submission in city hall.

PART 12- DESIGN OF ISOLATED FOOTING USING EXCEL FROM STAAD RESULT

This video shows how to design an isolated footing using excel from load result in staad.

This video below also shows isolated footing design using RCDC and verified with spreadsheet.

PART 5-GENERATING AUTOLOAD COMBINATION AND VERIFYING STAAD RESULT WITH SPREADSHEET

This shows how important the ff:

1. Defining load cases type will help you generate autoload combination according to your specified code.
2. Seismic weight depends on what dead load or mass you specified on the seismic definition.
3. Spreadsheet verification of seismic base shear accoring to NSCP/UBC 1997.

PART 6-DESIGN OF GRAVITY MEMBERS

This shows design of the following gravity members:

1. One way slab
2. Two way slab
3. Intermediate Beam

PART 7-DESIGN OF GRAVITY MEMBERS

This shows design of the following gravity members:

1. One way slab is designed using the spreadsheet.
2. Two way slab is designed using the spreadsheet.
3. Stringers or Intermediate Beam is designed using spreadsheet.

PART 8-DESIGN OF GRAVITY MEMBER(INTERMEDIATE BEAM)

Intermediate Beams or stringers are also gravity members that directly carries the slab loading and transferred them to girder.

PART 9-DESIGN OF GIRDER

The Girders which span from column to column carries loading from the intermediate beam and also part of the seismic resisting member of the building. This video shows the design of girder using the spreadsheet. Staad does not completely give a detailed design of girder because there are many considerations especially Code provisions in earthquake. Thus, a spreadsheet is important to guide the designer. For example, the minimum NSCP width of girder 250mm is not one of the parameter in staad.

PART 10-DESIGN OF GIRDER PART 2

Design of girder part 2.

This video also shows girder and intermediate beam design using RCDC and spreadsheet.

However, during further investigation of structure, revised design is done as shown below.

PART 11-DESIGN OF COLUMN

This video shows how to design or investigate the column using spreadsheet from analysis result in STAAD.

This video below shows column design using RCDC and verified in spreadsheet.

PART 3-ADDING DEAD LOAD, LIVE LOAD AND EARTHQUAKE LOAD IN STRUCTURE

This video shows how to add dead load, live load and earthquake load in your structure. It shows how important the staad editor in modeling because understanding the editor will help you edit the model quickly compared to doing it through GUI.

PART 2-SETTING UP DESIGN CRITERIA

Part 2 of design of building using staad and excel. Setting up the design criteria using a spreadsheet. Note that design criteria must be consistent with design drawings and design specifications.