It’s good to read this blog making and writing BOOKS is my passion..
It was that way right from the beginning, I’m sure. Carvers in stone, makers of runes, scribes in papyrus and parchment, right up to workaday paper — Hebrew, Greek, Latin, English — Making books is weary WORK, not glamour. Don’t take my word for it; here is Gabriel Garcia Marquez, author of, among many other long works, One Hundred Years of Solitude and Love in the Time of Cholera:
“Ultimately literature is nothing but carpentry. Both are very hard work. Writing something is almost as hard as making a table. With both you are working with reality, a material just as hard as wood. Both are full of tricks and techniques. Basically very little magic and a lot of hard work involved.”
Carpentry! But people persist in regarding writing…
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Reinforced Concrete Design. My blog which I used most of my time, research, writing about concrete design calculations….!!!
What makes Unique of RC…?
It is a COMPOSITE MATERIAL…
- It requires APPLICATION of more involved Principles of Mechanics…
- Structural Design is iterative requiring both ANALYSIS and DESIGN DECISIONS aided by judgment and EXPERIENCE.
- ACI 318 -the model code in the United States of America for guiding the design of RC members, look at Chapter 8.
- NSCP Code -the code in the Philippines..conforms to the provisions of ACI 318 Code!!!
Important Material Properties…
Concrete Strength and Steel Strength…
- 28-day Compressive Strength, f’c: ACI 318 Code 2011 edition, Chapter 5.
- Modulus of Elasticity of Concrete, Ec: ACI 318 Code 2011 edition, Chapter 8.5
- Strength property or yield strength, fy..
- Modulus of Elasticity of Steel, Es: 29,000,000 psi –ACI 318 Code 2011 edition.
1. –Procedures on how to Design Reinforced Concrete Beams!!!
Concrete Beam Sizing..!
Determination of Beam Size (b x h)—USE Spreadsheet or Hand Calculation!!!
Concrete Beam Size (b x h) or (b x d), FORMULA:
Area of Steel (As) determination!!!
The ACI Code 10.3.3 to 10.3.5 limits on the Steel Ratio (rho):
1.1 Minimum Beam Size for which Deflections are NOT LIKELY to be a Problem.
1.1.1 Set Neutral Axis distance, c = 0.375cb….
1.2 Arrangement of Rebars, Splicing points and splice length, development length, hooks requirement, and required Stirrups.
2. –Procedures on how to Design Reinforced Concrete Columns!!!
2.A. –Structural Design for column using Interaction Diagram!!!
2.B. –Example of ACI Interaction Diagram.
2.C. –Summary of Column Design Requirements!!!
2.1 Strength Reduction Factor, phi =0.70 -applicable up through ACI 318-1999; they have been changed to phi =0.65, for compression controlled members (columns and beams under compression controls) beginning with ACI 318-2002 Code, and continuing with the ACI 318-05 and 2008 up to present.
3.–Example: Design of Concrete Members, i.e. Frame Analysis, Beams, Columns, Footings using MS Spreadsheet.
- Design of Reinforced Concrete by Jack. C. McCormc, 3rd edition-1993, 7th edition-2005, 9th edition-2011;
- Design of Concrete Structures by Arthur H. Nilson, 12th edition -1997, International edition;
- Design of Concrete Structures by Arthur H. Nilson, 14th edition -2010, International edition;
- Reinforced Concrete (A Fundamental Approach), by Edward G. Nawy, 6th edition -2008,
- Reinforced Concrete, Mechanics and Design, by James K. Wight and James G. MacGregor, 6th edition -2012,
Being an engineer, excellent comprehension is necessary on how to make structural analysis for buildings, bridges, and other structures.
Structural analysis is the calculations of the magnitudes of forces, stresses, strains and deflections or deformations of structures when LOADS, external forces are being applied and exerted on structures.
The readers of this blogpost who are not engineers may very well amaze and ask; “Where in the world did they get these Loads?” “What on earth do they think they are weighing?” That very crucial and logical questions will be answered in this blogpost.
1. Specifications, Building Codes, and Bridge codes.
Designers must look for appropriate Specification and Codes. National and Local government have published building codes, bridge and highway codes for the safety purposes of the public, which control the construction of different types of structures within their country. Actually, these codes are laws or ordinances that specify design loads, design stresses, construction types, material quality among others. Not many specifications published recommended practices for local and national use. These codes and specifications are not enforceable legally, nevertheless, unless it is embodied in their national building code, and made integral part of a particular contract of projects. Among these organizations are;
- ASCE -American Society of Civil Engineers
- AASHTO -American Association of State Highway and Transportation official
- AISC -American Institute of Steel Construction
- ACI -American Concrete Institute
- ASEP -Association of Structural Engineers of the Philippines
The following specifications published by the above-mentioned organizations oftenly are used to estimate the maximum load and minimum loads to which the bridges, buildings, and other structures may be subjected during their estimated lifetimes.
- Minimum Design Loads for Buildings and other Structures, published by ASCE 7-2005 edition;
- AASHTO LRFD Bridge Design Specifications, published by AASHTO;
- Specifications for Structural Steel Buildings- 2010, published by AISC;
- Steel Construction Manual, 14 edition, published by AISC;
- National Structural Code of the Philippines, volume 1 -Buildings, volume 2 -Bridges, published by ASEP.
Readers of this bolgpost should pay attention that reasonable and clearly written codes are really helpful to designers.
The great pyramid in Egypt, the Parthenon in Athens, and the great Roman bridges and aqueducts built by ANCIENT BUILDERS were controlled by few specifications, which precisely is true. It should be spoken that only few number of these great structures were built over many 100 of years or centuries, and were ostensibly built WITHOUT CONSIDERATION or CARE about COST OF LABOR, MATERIAL, OR HUMAN LIFE. The were built probably by intuitions, and certain RULES OF THUMBS (“SINUBOK LAMANG” at KAWALAN O walang RASYONAL na PROSESO -in local dialect), developed by seeing the minimum size or strength of members that would fail only under certain given conditions. Their NUMEROUS FAILURES are NOT RECORDED in HISTORY, only their SUCCESSES ENDURED.
For the information and guidance of all readers of this blogpost, notably the ordinary engineers in the Philippines, I would like to give emphasis to them, that the national government agencies in the Philippines (DPWH, NIA, DOTC, DSWD-Kalahi) had adopted the latest international recommended practices and codes, like the ASCE standards, ACI Codes, AREA Code, AISC standards, ASTM standards. In view of the fact that ENGINEERING EDUCATION in the Philippines is AMERICAN ORIENTED, the ASEP committee decided to recommend the adoption of the Earthquake Regulation as provided in the Uniform Building Code.
Hence, the Association of Structural Engineers of the Philippines (ASEP) published National Structural Code of the Philippines as a referral code of the National Building Code of the Philippines. The NSCP code reflects the continuing technical advances in structural engineering and the latest seismic design practice for earthquake resistant structures, viz:
- Reinforced concrete design conforms to the provisions of the American Concrete Institute (ACI-318) Code.
- Bridges and highways specifications are patterned after the provisions of the AASHTO.
- The ASEP recommended Earthquake Regulations are patterned after the provisions of the Uniform Building Code (SEAOC) of the United States of America.
- The Minimum Design Loads for Buildings and other structures conforms to the provisions of American Society of Civil Engineers (ASCE 7-2005).
- Steel and Iron specifications are patterned after the provisions of the American Institute of Steel Construction (AISC) and American Standards for Testing of Materials (ASTM).
The Department of Public Works and Highways (DPWH) issued Department Order No.82-1, 1982;
“For the guidance and compliance of all concerned and pursuant to section 203 of PD 1096, the National Structural Code for Buildings a referral code of the NBC (PD 1096) to reflect the following;
- In Chapter 2, lateral forces, are revised to reflect the provisions of the Uniform Building Code (UBC-SEAOC)
- Chapter 4, Steel and Iron, conforms to the provisions of the American Institute of Steel Construction (AISC).
- Chapter 5, Concrete, conforms to American Concrete Institute -ACI 318 Code with the equations in SI Units.”
2. STRUCTURAL LOADS
Dead Loads: Weight of the structure under consideration, as well as any fixtures that are permanently attached to it.
Live Loads: They include occupancy loads, warehouse materials, construction loads, overhead service cranes, and equipment loads. They are gravity induced.
Environmental Loads: For Buildings, they are caused by rain, snow, wind, and earthquake.
2.1 Dead Loads
2.1.1 Weights of Common Building Materials
Reinforced Concrete -150 pcf
Concrete Hollow blocks (no plaster) -44 psf
G.I. roofing -2.5 psf
Suspended Ceiling -2 psf
Hardwood flooring -4 psf.
2.2 Live Loads
2.2.1 Typical Uniformly Distributed Live Loads:
Residential dwelling areas -40 psf
Classrooms in schools -40 psf
Offices in office buildings -50 psf
Retail stores -first floor -100 psf
Retail stores -upper floor -75 psf
Dance hall and ballrooms -100 psf
Library reading rooms -60 psf
2.3. Lateral Loads:
There are certain loads that are almost always applied horizontally.
Wind Loads, soil pressures, hydrostatic pressures, forces due to earthquakes, centrifugal forces, and longitudinal forces.
2.3.1 Wind Loads
A.1 The basic reference equivalent static pressure in the critical local wind speed.
qs = 0.0000483V^2
V = wind velocity in KPH
qs = in kPa
Applicable to Duchemin formula (developed in 1829)
1. Duchemin Formula..
Pn = p (2 sinϴ/1 + sin^2ϴ) — Wind Pressure normal to an inclined roof surface.
American Society of Civil Engineers (ASCE) Recommendation:
2.3.2 EARTHQUAKE LOADS or FORCES (EQ),
126.96.36.199 STATIC LATERAL FORCE PROCEDURE
A. Uniform Building Code (UBC)
3. SYSTEM LOADING:
3.1 Tributary Area Loading.
3.2 LOADING CONDITIONS FOR STRENGTH DESIGN:
3.2.1 LOAD COMBINATIONS,
A. ACI Code -1963 to 1971,
- 1.5D + 1.8L
- 1.25 [ D + L + W]
- 1.25 [ D + L + EQ]
B. ACI Code -1977 to 1999,
- 1.4D +1.7L
- 0.75 [1.4D +1.7L +-1.87EQ]
C. ACI Code -2002 to 2011,
- 1.2D + 1.6L
- 1.2D + 1.0L + 1.0EQ
- 1.2D + 1.0L + 1.6W
- Structural Analysis by Aslam Kassimali, 4th edition, 2011,
- Structural Analysis by R. C. Hibbeler, 8th edition, 2012
- Structural Analysis by J. C. McCormac, 2nd edition, 1997,
- Structural Analysis Design of Tall Buildings, by Taranath, 2012,
- Structural Analysis by Venancio Besavilla, 2007 edition;
- Structural Analysis by Matias A. Arreola, 1992;
- Wind and Earthquake Resistant Building, by Taranath, 2011,
- ASCE 7- Minimum Design Loads for Buildings and other Vertical Structures, 2010,
- Standard Specifications for Highway Bridges, AASHTO 2007;
- Building Code Requirements for Structural Concrete, ACI 318 Code 2011 edition;
- Uniform Building Code (UBC) -1997,
- Structural Engineering handbook,
The average person thinks that concrete has been in common use for many centuries, but such is not the case. Although the Romans made cement – called Pozzolana – before Christ by mixing slaked lime with a volcanic ash from Mount Vesuvius and used it to make concrete for building, the art was lost during the Dark Ages 5th century -15th century A.D. and was not revived until eighteenth and nineteenth centuries (A. D.). Marcus Vitruvius Pollio, Vitruvius, an Architect/Engineer during the golden age of Caesar Augustus (around 25 BC). In his writings around 25 BC in Ten Books on Architecture distinguished types of aggregate appropriate for the preparations of lime mortars. For the use of structural members, he recommended pozzolana, which were volcanic sand from the sandlike beds of Puteoli, brownish-yellow-gray in color near Naples and reddish brown at Rome. He specifies 1 part lime to 3 parts…
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STRUCTURAL ANALYSIS as we know it today evolved over several thousand years. During this time many types of structures such as beams, arches, trusses and frames were used in construction for Hundred or even thousand of years before satisfactory methods of analysis were developed for them.
While ancient engineers showed some understanding of structural behavior (as evidenced by their successful construction of bridges, cathedrals), real progress with the theory of structural analysis occurred only in the past 150 years.
The EGYPTIANS and other ancient builders surely had some kinds of empirical rules drawn from previous experiences for determining sizes of structural members. There is, However, NO EVIDENCE that they had developed any THEORY of STRUCTURAL ANALYSIS. The Egyptian Imhotep built the great PYRAMID of Saqqara, the Step Pyramid of Djoser Egypt’s first pyramid, built during the third dynasty of the old kingdom in circa 2630 B.C. sometimes is referred to…
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In my standpoint, killings done by ruthless and reprobate people are the works of evil, EVIL who entices people to do beyond the limits of their sanity and senses and the freewill, freedom to choose given by God to us. To do what is bad in the eyes of God, because the worldly desires are severe, the desire for power, for fame, and greed for money even to the extent of killing people, being a false witness. To name God’s commandments, viz:
- Thou shall not kill;
- Thou shall not steal;
- Thou shall not make false witness against your fellowman;
Here are signs of greed for power, selfishness, enviousness, political killings and transgressions of the law of God:
People in power are not satisfied with their honor and fame; victorious political party have used their powers for political persecution against the people who supported their political rival and other political…
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My passion for Structural Engineering, I focused my sight to delve into many books for Structural Analysis and Design calculations, so most of the time given to me by God, I used to study and to research the history of this interesting major subjects in civil engineering;
- Structural Reinforced Concrete Design;
- Structural Steel Design;
- Timber Design;
- Engineering Mechanics;
- Strength of Materials (Mechanics of Materials),
- Theory of Structures;
- Transportation Engineering;
- Soil Mechanics and Foundation Design;
- Differential and Integral Calculus;
- Analytic Geometry;
- Plane Trigonometry;
- Advance Algebra.
Having a lot of experiences in life, and my passion for structural engineering, I was challenged to research and study continuously particularly structural engineering. Fortunately, I have collected and acquired many books, design codes for civil engineers valued in US Dollars, namely;
- ACI Manual of Concrete Practice, 2008 -American Concrete Institute;
- ACI Design handbook, 2004 -American Concrete Institute;
- ACI 318-Building Code Requirements for Structural concrete, 2011 edition,
- DETAILING MANUAL 2004 edition,
- PCI Design Handbook, Precast and Prestressed Concrete-7th edition,
- CRSI Design Handbook, 2008 edition,
- ASCE 7 Standard-Minimum Design Loads for Buildings and other Vertical Structures,
- Uniform Building Code (UBC),
- British Steel Designer’s Manual 6th edition,
- American Steel Construction manual 13th edition,
- National Structural Code of the Philippines 2001 edition, etc.
- Numerous Historic Books in Civil Engineering, e.g. Theory of Structures, Reinforced Concrete, Mechanics of Materials, Mechanics of Engineering dated 1750 A.D. to 1930 A.D.
|ACI 2008 -MANUAL OF CONCRETE PRACTICE|
|ACI 2008 MANUAL OF CONCRETE PRACTICE|
Actually, since 1995, I started collecting books and studied most of the time if no projects to be supervised. In my eagerness to acquire more knowledge, I focused my mind and sight to study and research the structural analysis and design calculation methods to make works easier for civil / structural engineers and structural designers.
I have a friend who has the desire in structural analysis and design computations and construction, this friend of mine is not really a recognized Structural Engineer by Professional Regulation Commission or by Philippine Institute of Civil Engineers (PICE), but he is just a practicing engineer; Fabian, he used to design simple buildings, he constructed some buildings in Catarman town, I doubted the method of calculations he used because he uses the balance condition in concrete designs. The method he used was erroneous it should be actual condition of the concrete columns.
I had met a lot of people with different characters and personalities, the SCRUFFY, the CLEAN, the INCOMPLETE, the DEFENSIVE ones, the NONCHALANT and the BRILLIANT ones. As much as there are differences in people’s character, so is there, in their works and calculations. Also, to mention, through social networking I have acquired computer software, e.g. Microsoft Excel Spreadsheets software for design, and adopted their procedures, methodology and style with some modification to suit my satisfaction and method of analysis. Further, through social networking I had learned to develop Spreadsheets for my analysis and design since 2006 up to present, I am self taught in Microsoft Excel and had developed frames and beams analysis, concrete beams, concrete columns, footings in metric versions.
I used to think that being a practicing engineer for almost two decades, I surmise myself as a Structural design engineer already, like for instance professor Besavilla who authored reviewer books, and also Gillesania also authored reviewer books, my friend Redeem Legaspi a software programmer who developed steelpro program, they are all considered structural engineer. Accordingly, in my in-depth study and research, I had learned various methods for Structural Analysis in ‘Hand’ or conventional method with the aid of calculator and also using computer software, namely;
- MS-Excel Spreadsheets software,
- STAAD software,
- PCA software,
- ETABS, SAP2000, SAFE design software.
In my more than 22 years of experience as practicing engineer with continuous research, study, practice solving for building frames/beams and bridge structures, I have acquired knowledge and become Structural design engineer. Henceforth, as structural design engineer and specialist, I prefer to use the method developed by Professor Hardy Cross the Moment Distribution.
HARDY CROSS method (innovation), to me it’s the best method for Structural Analysis and Design Calculation, developed by Professor Hardy Cross in 1924. He published the method in the proceedings of the American Society of Civil Engineers in May 1930 after having taught the subject to his students at the University of Illinois since 1924. His Paper began a new era in the Analysis of Statically indeterminate frames and gave added impetus to their use. This method can be used in complex building frames, continuous beams and simple beams and or vertical structures.
Uniformly Distributed Load:
M = W(L^2)/12 for fixed end moment
Concentrated Load or Point Load:
M = Pa(b^2)/L^2 fixed end moment
M = Pb(a^2)/L^2 fixed end moment
Prof. Hardy Cross method was a popular method and was used for the Analysis of Continuous Beams and Frames and in Structural Engineering as a “Hand Calculations method and/or Conventional Calculations method” from 1930 until 1960. Since the 1960s, however, there has been an ever increasing use of computers for the analysis of all types of structures. Computers are extremely efficient for solving the simultaneous equations that are generated by other methods of analysis. Generally, computers software used is developed from the matrix-analysis procedures. Reference: J. C. McCormac, S.E., Structural Analysis.
I developed a spreadsheet for Continuous Span Frame Analysis using Hardy Cross method:
My passion for reinforced concrete design is worth to press.