World’s longest tunnel “Gotthard Base Tunnel” : Hot Topic

After two decades’ construction, the Gotthard Base Tunnel in southern Switzerland broke through the final 1.8 meters Friday to create the world’s longest tunnel at 57 kilometers.

Civil Engineering Award for Delhi Metro

The Delhi Metro Rail Corporation(DMRC) has won the Outstanding Civil Engineering Project Award for the year 2010 specially for completing various infrastructural projects in record time, an official said today. The award will be given by the international Asian Civil Engineering Coordinating
Council(ACECC). The council works for the promotion and advancement of the science and practice of civil engineering and related professions for sustainable development in the Asian region.

The award is given to agencies involved in infrastructural projects that have made exemplary contribution to the progress of civil engineering works.

The project taken up by the agency should contribute to the nation where the project is located and they should have impacted on or spread through other Asian nations or ACECC member economies.

Work on a 125-km stretch of the Delhi Metro is in progress in Phase II and will be completed before the Oct 3-14 Commonwealth Games. Large sections of this have already been opened for the public.

What is Porous Pavements?

What is Porous Pavements?

Porous pavements, both asphalt and concrete have been around for years.  In most areas they haven’t really caught on.  Now, with the large focus on environmental issues and green building, are they worth looking at again?
Pavement design
Traditional pavement design
Typically when pavement mixes are designed, they include different sizes of aggregate.  They use a wide range from fine sand to coarse stone.  The largest size depends on the expected use of the material.  Then it is all bound together with binder or cement.  With asphalt pavement that top layer will go on a water proof layer then a base.  Concrete pavement may go on a base or directly on the ground.
This results in an impenetrable surface that blocks rain water from getting into ground water systems and increases runoff.
Porous pavement design
Porous pavement or pervious pavement is designed using medium and large sized aggregate without any smaller fines such as sand.  It is then held together using with cement or binder.  The lack of fines in the mix creates relatively large pore space in the pavement.  This large pore space allows water to pass through.
The top layer is placed either directly on the ground or on other porous base layers to allow water to drain completely through the system into the ground.
Pros and Cons
Here are some pros and cons as well as a few notes on them.
Pros
Increased water quality – Oils, heavy metals and other contaminates on the pavements are not carried downstream and into stormwater drainage systems.  Also, water is filtered as it passes through the pavement.
Lower initial construction costs – Construction costs may be lower because porous pavements lower the amount of stormwater drainage facilities that a site will need.  Fewer and smaller inlets, detention ponds and storm drain pipes means lower construction costs.
Lower long term costs – less maintenance needed for storm drain and filtration systems.
Fewer fees – Storm water impact fees may be lower since porous pavements are proven to reduce runoff.
Less runoff – Less runoff means less potential flooding and lower peak flows.
Increased safety – Since water drains through the pavement there is a lower chance of hydroplaning and an increase in traction.
LEED Points – It can indirectly help gain LEED Points.  It can contribute in the areas of Stormwater Design, Heat Island Effect, Water Efficient Landscaping, Recycled Content, and Regional Materials.  There may be other ways that using it can help LEED certification.
Cons
Higher initial construction cost – Yes, I know I listed construction cost as a pro also.  The cost of constructing the pavement itself tends to be higher than regular pavement.
Soil restrictions – The soil below the pavement must drain at least as well as the pavement.
Clogging – The pores in the pavement may clog.  Suppliers and other proponents say that regular cleaning and maintenance will nearly eliminate clogging.
Pavement strength – Porous pavements are structurally weaker than standard pavements.   That generally results in them being used only for low traffic roads and parking lots.  Extra care must be taken when designing a pavement for high traffic or heavy traffic.
New/Untested technology – That’s not entirely accurate.  The technology has been tested since at least 1971.  However, most contractors don’t have experience with it.  Proper training, clear instructions, material testing, and site investigations should be done to ensure that the pavement meets all applicable standards during construction.
Contamination – Pavement surfaces usually have a lot of contaminates on them.  Porous pavements can filter contaminants, but no system is 100%.  Since water drains directly into ground soil it is possible that it will take the contaminants with it.
Conclusions
There is a lot of potential for porous pavements in future projects.  Each project would have to be investigated independently to determine any cost or environmental savings that might be gained by using porous pavements.  However, the potential positives do seem to outweigh the potential negatives.  It would certainly be worth your time to investigate it and present your findings to your client.
What are your thoughts on Porous and Pervious Pavements?

What is Right of Way (ROW)?

What is Right of Way (ROW)?


Right of Way (ROW)is something that civil engineers work with a lot. It’s on virtually all of the surveys that we use. It’s a key point that must be known if you’re working on a project where private property meets public property. This is especially important when working on transportation projects for local governments. There are a lot of aspects to Right of Way and Right of Way Acquisition. I’m going to talk about it mainly from the transportation side.

What is Right of Way

Here’s an example of what Right of Way (ROW) is. A city owns a public street that goes through a residential neighborhood. They also own a few feet past the pavement on both sides of the street. If a residential street is 30-36 feet wide the city may own a total of 46-50+ feet wide area. So, yes they own part of your front yard. Virtually all public streets are like this, from local residential streets on up to interstate highways which may have ROWs that are hundreds of feet wide.

Why Right of Way

The government holds a right of way wider than the actual street for several reasons. They use the extra land for things like public sidewalks, utilities, or to widen the road in the future. Also, street lights, traffic signals and street parking are all in the ROW.

Right of Way is something that we have to know where is, but civil engineers don’t typically worry about why it’s where it is or how to get more. That sort of thing is typically handled by the government agency itself. Or was figured out when the property was first developed. Civil engineers don’t generally get more once an area is already developed.

However, I’ve had the privilege recently to work on a ROW acquisition project recently. That’s a service that our company offers, and my background in roadway design helped get me involved in a roadway ROW project.

The project

Here are the basics of the project. A two lane county road needed to be widened because of all of the development nearby. Plans were drawn up and the road was designed, but the county didn’t actually own enough land to make the road wider. That’s where we came in on the project. The county hired us to acquire the land for them.

What you have to do

There are several steps involved in ROW acquisition. I’m going to go over the broad steps. Perhaps at a later date I’ll write a more detailed article, or ask our resident expert to put one together for me.

Survey

It seems that everything in civil engineering begins with a survey. The same applies here. With the survey and the plans we can see exactly how much land is needed from each land owner. The surveyor provides documents showing exactly how much land is needed. They generally will also mark the area with flags or other markers.

Initial Letter

An initial letter is sent to the current land owner to let them know about the surveyors and appraisers coming onto their property. The letter also lets the owner know what’s going on with the project; the whys, the whos, etc.

Appraisals

Next the appraisers go to work. They appraise each plot of land that the government needs to buy. The appraisers generally will take into account mailboxes, fences, trees and anything else that may be in the proposed right of way area that current land owner would have to move or lose value if it’s removed.

Title Search

Just like when you buy any piece of property, you do a title search to find out who actually owns the land. This will also tell you about any liens on the property such as a mortgage, tax lien or unpaid debt. Any lien will affect the sale.

Offer Letters

Send the initial offer letter. Basically the offer is for what the appraiser valued the land at.

Negotiation

This can be real long or real short depending on what the land owner wants. I’ve seen some just sign the paperwork and send it back. Some think their land is worth more, some will want fences or custom mailboxes replaced, trees paid for, or many other things. Some just flat out refuse to sell. In most cases something can be worked out to the benefit of both the land owner and the municipality.

Partial Release of Lien

We do have to deal with any liens that are on the property. If there is a mortgage, for example, we have to get a partial release of lien. Basically the bank has to give up that part of the land on their deed. Lien holders may have the right to the money first. That varies some by location. Banks sometimes require a percentage of the money based on a percentage of the property sold.

Acceptance or Condemnation

Eventually, after the negotiations, the land owner accepts or they don’t. If they accept, then the paperwork is signed, they get their money and the government gets the land. If they are unwilling to sign, then it goes to condemnation. That means that it goes before a third party to decide the case. Generally when this happens the government gets the land and the land owner gets fair market value for their property. Because of the expense it really doesn’t do anybody any good to go to condemnation. As long as we follow the laws and our engineering ethics guidelines we are fine.

There is a lot more to it, but that covers the basic process. It is certainly a good thing to know, even if you never do ROW acquisition yourself. Having the knowledge gives you a better understanding of the process and what the municipality has to do on some projects. However, having the expertise can give your company another product to offer municipal clients.

Reinforced concrete Design philosophy and concepts

The design of a structure may be regarded as the process of selecting proper materials and proportioned elements of the structure, according to the art, engineering science and technology. In order to fulfill its purpose, the structure must meet its conditions of safety, serviceability, economy and functionality.

Serviceability: No excessive deflection, no excessive deformation and no cracking or vibrations No excessive reinforcement. Must be able to perform the function, it is built for.

Strength design method

It is based on the ultimate strength of the structural members assuming a failure condition, whether due to the crushing of concrete or due to the yield of reinforced steel bars. Although there is additional strength in the bar after yielding (due to Strain Hardening), this additional strength in the bar is not considered in the analysis or design of the reinforced concrete members. In the strength design method, actual loads or working loads are multiplied by load factor to obtain the ultimate design loads. The load factor represents a high percentage of factor for safety required in the design. The ACI code emphasizes this method of design.

Working stress design

This design concept is based on elastic theory, assuming a straight line stress distribution along the depth of the concrete. The actual loads or working loads acting on the structure are estimated and members are proportioned on the basis of certain allowable stresses in concrete and steel. The allowable stresses are fractions of the crushing strength of concrete (fc') and the yield strength (fy). Because of the differences in realism and reliability over the past several decades, the strength design method has displaced the older stress design method.

Limit state design

It is a further step in the strength design method. It indicates the state of the member in which it ceases to meet the service requirements, such as, loosing its ability to withstand external loads or local damage. According to limit state design, reinforced concrete members have to be analyzed with regard to three limit states:

1. Load carrying capacity (involves safety, stability and durability)
2. Deformation (deflection, vibrations, and impact)
3. The formation of cracks

The aim of this analysis is to ensure that no limiting sate will appear in the structural member during its service life.

What is LRFD?

Limit state design (LSD) refers to a design method used in structural engineering. The method is in fact a modernization and rationalization of engineering knowledge which was well established prior to the adoption of LSD.[citation needed] Beyond the concept of a limit state, LSD simply entails the application of statistics to determine the level of safety required by or during the design process for LRFD from Bridge Design, please read this book about Design of Highway Bridges: An LRFD Approach

Criteria

Limit state design requires the structure to satisfy two principal criteria: the ultimate limit state (ULS) and the serviceability limit state (SLS).[1] A limit state is a set of performance criteria (e.g. vibration levels, deflection, strength, stability, buckling, twisting, collapse) that must be met when the structure is subject to loads.

Example Treatment of LSD in Codes

The following is the treatment of LSD found in the National Building Code of Canada:

NBCC 1995 Format
φR > αDD + ψ γ {αLL + αQQ + αTT}

where φ = Resistance Factor
ψ = Load Combination Factor
γ = Importance Factor
αD = Dead Load Factor
αL = Live Load Factor
αQ = Earthquake Load Factor
αT = Thermal Effect (Temperature) Load Factor


Any design process involves a number of assumptions. The loads to which a structure will be subjected must be estimated, sizes of members to check must be chosen and design criteria must be selected. All engineering design criteria have a common goal: that of ensuring a safe structure and ensuring the functionality of the structure.
The State of the Art

Limit state design has replaced the older concept of permissible stress design in most forms of civil engineering. Notable exceptions are geotechnical engineering and transportation engineering. Even so, new codes are currently being developed for both geotechnical and transportation engineering which are LSD based. As a result, most modern buildings are designed in accordance with a code which is based on limit state theory. For example, in the UK, Steel structures are designed in accordance with BS 5950, and reinforced concrete structures to BS 8110, both of which are codes based on limit state theory. Australia, Canada, China, France, Indonesia, and New Zealand (among many others) utilise limit state theory in the development of their design codes. In the purest sense, it is now considered inappropriate to discuss safety factors when working with LSD, as there are concerns that this may lead to confusion.
Limit State Design in the United States

The United States has been particularly slow to adopt Limit State(s) design (known as Load and Resistance Factor Design in the US), and as a result it is more thoroughly adopted outside the United States. Inside the U.S. there has been significant resistance to this technique, so much so that the American Institute of Steel Construction (AISC) is now issuing a combined manual of steel construction (the 2005 manual) that contains two methods of design side by side (newly named ASD - Allowable Strength Design, not to be confused with ASD - Allowable Stress Design last updated in 1989), and LRFD - load and resistance factor design).[citation needed] In terms of the US steel code, research and progress has been reserved to LRFD code, with the exception of addenda regarding safety concerns. Even so, many American engineers continue to prefer the former ASD code. The difficulty may lie in the high regionalization of US Engineering practice, coupled with the high number of governing bodies, codes and states which each regulate the engineering profession individually.

Best Introduction to Earthquake Engineering Available!

This is the book for everyone who is not familiar with Earthquake and would like to explore more what is Earthquake. You can also read some information in my blog first and then probably read more in the book on Fundamentals of Earthquake Engineering.
Book is designed for a graduate level course that introduces a "source to society" model for earthquake engineering that wonderfully captures the importance of interaction between the structural engineers (whom the book is primarily written for) and geologists, seismologists, geotechnical engineers, and public policy planners. The majority of the technical content focuses on the "source to structure" path of demand imposed by seismic events coupled with structural evaluation of the supply of buildings. This is a perfect introductory book to the topic, which covers selection of records for use in seismic analysis better than other books of its type. The book stops where the seismic codes start, so the text will not be outdated by future changes to codes. The author has put great effort into compiling a thorough list of top quality sources at the end of each of the four chapters (two focusing on demand and two on supply) that will be useful to the student desiring to delve deeper into various topics covered. Included with the text are access to powerpoint slides for all 4 chapters and 2 appendices, solutions to the example problems given throughout the chapters, and source data from several events discussed in the text.
You might would like to read more on Product Description and its back cover.Fundamentals of Earthquake Engineering combines aspects of engineering seismology, structural and geotechnical earthquake engineering to assemble the vital components required for a deep understanding of response of structures to earthquake ground motion, from the seismic source to the evaluation of actions and deformation required for design.

The nature of earthquake risk assessment is inherently multi-disciplinary. Whereas Fundamentals of Earthquake Engineering addresses only structural safety assessment and design, the problem is cast in its appropriate context by relating structural damage states to societal consequences and expectations, through the fundamental response quantities of stiffness, strength and ductility. The book is designed to support graduate teaching and learning, introduce practicing structural and geotechnical engineers to earthquake analysis and design problems, as well as being a reference book for further studies.

Fundamentals of Earthquake Engineering includes material on the nature of earthquake sources and mechanisms, various methods for the characterization of earthquake input motion, damage observed in reconnaissance missions, modeling of structures for the purposes of response simulation, definition of performance limit states, structural and architectural systems for optimal seismic response, and action and deformation quantities suitable for design. The accompanying website at www.wiley.com/go/elnashai contains a comprehensive set of slides illustrating the chapters and appendices, as well as a set of problems with solutions and worked-through examples. The book, slides and problem set constitute a tried and tested system for a single-semester graduate course. The approach taken avoids tying the book to a specific regional seismic design code of practice and ensures its global appeal to graduate students and practicing engineers.
From the Back Cover
Fundamentals of Earthquake Engineering combines aspects of engineering seismology, structural and geotechnical earthquake engineering to assemble the vital components required for a deep understanding of response of structures to earthquake ground motion, from the seismic source to the evaluation of actions and deformation required for design.

The nature of earthquake risk assessment is inherently multi-disciplinary. Whereas Fundamentals of Earthquake Engineering addresses only structural safety assessment and design, the problem is cast in its appropriate context by relating structural damage states to societal consequences and expectations, through the fundamental response quantities of stiffness, strength and ductility. The book is designed to support graduate teaching and learning, introduce practicing structural and geotechnical engineers to earthquake analysis and design problems, as well as being a reference book for further studies.

Fundamentals of Earthquake Engineering includes material on the nature of earthquake sources and mechanisms, various methods for the characterization of earthquake input motion, damage observed in reconnaissance missions, modeling of structures for the purposes of response simulation, definition of performance limit states, structural and architectural systems for optimal seismic response, and action and deformation quantities suitable for design. The accompanying website at www.wiley.com/go/elnashai contains a comprehensive set of slides illustrating the chapters and appendices, as well as a set of problems with solutions and worked-through examples. The book, slides and problem set constitute a tried and tested system for a single-semester graduate course. The approach taken avoids tying the book to a specific regional seismic design code of practice and ensures its global appeal to graduate students and practicing engineers.

Design of Highways Culvert

Designing Highway culverts

A highway culvert is a drainage facility that allows water to flow under the road without causing any traffic disruption. Corrugated and spiral steel pipe are popular for culverts because they can be installed quickly, have long life, are low in cost, and require little maintenance. With corrugated steel pipe, the seam strength must be adequate to withstand the ring-compression thrust from the total load supported by the pipe. This thrust C, lb/ft (N/m), of structure is

C=(LL+DL)S/2

where
LL= live-load pressure, lb/ft2 (N/m2)
DL= dead-load pressure, lb/ft2 (N/m2)
S= span (or diameter), ft (m)

The pipe should have sufficient handling and installation strength so as to withstand stresses due to shipping and placing of the pipe in the desired position. The handling strength is measured by a flexibility factor which is:

FF=D2/EI

where
D =pipe diameter or maximum span, in (mm)

E= modulus of elasticity of the pipe material, lb/in2
(MPa)

I =moment of inertia per unit length of cross section of the pipe wall, in4/in (mm4/mm)

more about Highways Culvert