Wednesday, February 28, 2018

Foot-over Bridges In Mumbai constructed by the Indian Army in less than 3 months

Railway Minister Piyush Goyal and Maharashtra Chief Minister Devendra Fadnavis inaugurated three much-awaited railway foot overbridges (FOBs), constructed by the Indian Army in less than 3 months, for public in Mumbai.
The 3 FOBs are at these stations-

  • The FOB at Elphinstone Road is 73.1 metres long & 3.65 metres wide and built at a cost of Rs 10.44 crore within 117 days.
  • The Currey Road FOB is 30 metres long & 3.5 metres wide built at the CSMT end from the east side platform at a cost of around Rs 3 crore.
  • The Ambivali FOB connecting 2 platforms is 20 metres long and 3.5 metres wide, built at a cost of Rs 2.70 crore.

India First Hyperloop between Pune and Mumbai

Source: Virgin Hyperloop one

Monday, February 26, 2018


Advantage of Raft Foundation

  • Raft or mat foundation is economic due to combination of foundation and floor slab.
  • Better water- proofing treatment ease of  reinforcement fabrication and laying of concrete.
  • Mat foundation is one of the most dependable solution to uneven and difficult land areas. Sometimes the soil has a low bearing capacity while other times, making individual footing is not feasible. A mat foundation is the solution to these problems.

  • The excavation required for the mat foundation is way less than what is required by other foundation. This saves resources, labor as well as money.
  • In case of soil having low bearing pressure, Ultimate Bearing capacity increases with increase width of the foundation. Settlement decreases with increase depth. The amount of differential settlement between various parts of a structure is much lower than that if the same structure was supported on individual footing. Hence, maximum total settlement which can be allowed for a particular structure is more than what is permitted when the structure is resting on individual footing.
  • Mat foundation is perfect for soil that is subjected to subsidence. For e.g. clay is a kind of soil that keeps on contracting and expanding as the temperature changes, this is why, building a structure directly on the soil can make it dangerous.
  • It reduces differential settlement.
  • The soil has a low bearing capacity so the weight of the building needs to be spread out over a large area to create a stable foundation.
  • If the walls of the building are so close that it would cause the individual footings to overlap, then raft foundations should be used.

Saturday, February 24, 2018

Why The Bullet Train Will Be A Boon For Mumbai

Even as officials are talking about how India's first bullet train, which will connect Mumbai and Ahmedabad, is likely to transform inter-city travel, the question on one's mind is, what's in it for Mumbaikars? Aanchal Khare, managing director of National High Speed Rail Corporation Limited, the company spearheading the project, said, the train will not only shrink travel time between locations in Mumbai by half, there are also plans to connect the train with the existing metro lines.
The 12 stations proposed between Mumbai and Sabarmati, include Mumbai BKC, Thane, Virar, Boisar, Vapi, Bilimora, Surat, Vadodara, Anand/Nadia, Ahmedabad and Sabarmati. While the end-to-end cost between Mumbai and Sabarmati is expected to go up to Rs 3,000, travelling between BKC and other local stations in Mumbai could cost anywhere from Rs 250 to Rs 750.
The trains will run at an operating speed of 320 kmph, between 6 am and midnight. As per the proposed timetable, travelling between BKC and Thane will take 10 minutes, while Virar will be covered in 24 minutes flat.
“The tendering and ground work will begin by June 2018 and the line should be up and running in the next four years. We are confident, it [the bullet train] will revolutionse rail transport,” Khare said.

Low Density and Thermal Efficient Concrete for Terrace Overlay

New Picture.jpg
Ramakrishna Mission - a renowned charitable organisation, Belur Math, Kolkata were facing a problem of water seepage on their top floor. Additionally they wanted to maintain an even level on the terrace, which will reduce the seepage problem. But since this is an old and heritage structure they were looking for a product that will not increase the dead load on the structure at the same time enhance thermal insulation and effectively replace Brickbat Coba(BBC) and floor tiles. Based on these problems, Nuvoco suggested Mega Light Weight Concrete (LWC), which will help in achieving the regular level of the floor without increasing any dead load on the structure. Altogether 46 cum was supplied with a density of 1000/1200 kg/cum.
Mega Light weight Concrete from Nuvoco offers a density of 800- 1800 kg/m3 while reducing the structural weight and is an efficient alternative to brickbat coba. It is a low density and thermal efficient concrete and has a quick turnaround time with consistent qualtiy.

  • Better thermal insulating capability
  • Easier to place and saves time (surface is ready to use within 24hrs)
  • Reduces dead load on existing structures
  • Exceptionally low densities are available up to 800 kg/cum.

Thursday, February 22, 2018

How to calculate weight of mild steel bar?

Weight =  Volume x density
Since its cylindical shape
Volume of bar = pi()*h*(d²)/4 mm³
where h is height of cylinder bar
d is diameter in mm
Weight density of steel = 7850 kg/m³
Here we considering for 1m length, so h = 1m
Volume of bar = pi()*h*(d²)*(10⁻⁶)/4
= pi()/4*h*(d²)*(10⁻⁶)
Here we have coverted dia from mm to m
Volume of bar = (7.85*(10⁻⁷))*(d²)
Weight of bar = Weight density x Volume
or unit weight of steel = 7850*(7.85*(10⁻⁷))*(d²)
= 0.00616225 *d²
or can be written as = d²/ 162
where d is diameter of bar in mm
25mm bar weight per meter = 25*25/162
= 3.858024691 kg
Weight of steel = (d²/162)*length

Wednesday, February 21, 2018

Corrosion Monitoring of Reinforced Concrete Structures

Corrosion Monitoring of Reinforced Concrete Structures
A proper test plan should take into account the following considerations:

  1. Exposure condition (Access to moisture, oxygen, exposed to de-icing salts, other chemicals, carbon dioxide);
  2. Geometry of the structures and components;
  3. Access to structural and non-structural components;
  4. Dimension and scale of the area under investigation;
  5. Importance of the element, etc.
The following inspection procedures are widely used during a routine corrosion monitoring program:
Chain Drag Delamination Survey
Chain dragging is widely used to detect delamination in concrete bridge decks. The concept behind this very simple method is the unique hollow sound that is made by dragging chain across the delaminated surface. The test is used to identify potentially delaminated areas on the deck slab.
The practice is difficult when vehicles are moving over the deck, and distinguishing the hollow sound becomes difficult.
The main disadvantage of the chain dragging method is that they can only provide results if the defect and deterioration are in well advanced stages. Early diagnosis of damage mechanism is not possible using this technique. Application of the method is somewhat difficult during heavy traffic.

Tuesday, February 20, 2018

10 Interesting Structures Opening in 2018

  • Grand Egyptian Museum, Giza
The Grand Egyptian Museum has been described as the largest archaeological museum in the world. The building is shaped like a chamfered triangle and sits on a site two kilometres west of the pyramids. The building's north and south walls line up directly with the Great Pyramid of Khufu and the Pyramid of Menkaure. The front facade of the museum will feature a translucent stone wall, made of alabaster. Inside the main entrance is a large atrium, where large statues will be exhibited.

  • 3 World Trade Center, New York
3 World Trade Center is a skyscraper being built as part of the rebuilding of the World Trade Center site in Lower Manhattan, New York City. The building will have a height of 329m with 80 stories.
3 WTC has a load-sharing system of diamond-shaped bracing, which helps to articulate the building's east-west configuration. This allows unimpeded 360-degree panoramic views of New York.

Wednesday, February 07, 2018

Structural Engineering Emergency Response (SEER)

As structural engineers, we make a difference in peoples’ lives every day as we help to ensure society’s health, safety, and welfare. This past year, many structural engineers took this responsibility to another level in the aftermath of Hurricanes Harvey (in Texas) and Irma (in Florida).
Structural engineers took a leadership role as 2nd Responders to these natural disasters through the Structural Engineers Emergency Response (SEER) Program. Structural engineers performed damage and safety assessments of communities devastated by the hurricanes to determine whether structures were suitable for re-habitation.
At the state level, SEER Committees, as part of their State Structural Engineers Association (SEA), work to recruit and educate members to become 2nd responders. At the national level, NCSEA and its SEER Committee work to establish relationships with allied organizations to support its SEA SEER Committees by focusing on the following four issues:

Monday, February 05, 2018

How to Perform Pile Integrity Test?

Pile integrity test (PIT) is low strain impact integrity test, is a common non-destructive test method for the
-Evaluation of pile cross-sectional area and length, the pile integrity and continuity, as well as consistency of the pile material.
-Forensic evaluations on existing piles, or quality assurance in the new construction.
The integrity test is applicable to driven concrete piles and cast-in-place piles.
Low strain impact integrity testing provides acceleration or velocity and force (optional) data on slender structural elements. Sonic Echo (SE) and Impulse Response (IR) are employed for the integrity test on deep foundation and piles.
The PIT method works best for column type foundations, such as piles and drilled shafts.

How to Perform PIT?

The pile head surface should be accessible, above water, and clean of loose concrete, soil or other foreign materials resulting from construction. Any type of contamination should be removed (using a grinder) to reach to solid and sound concrete surface. This step is so vital, because then connection between the sensor and concrete should be solid (firm contact). The location of the sensor should be selected away from the edges of the pile. The integrity testing should be performed no sooner than 7 days after casting or after concrete strength achieves at least 3/4 of its design strength, whichever occurs earlier.
A hammer (with or without force measurement unit) is used for impacting pile top; the impact should be applied axially with the pile. Motion transducer should be capable of detecting and recording the reflected echos over the pile top. Acceleration, velocity, or displacement transducers can be used for this purpose. At the minimum, acceleration transducer should have an Analog to Digital Converter with 12 bit resolution; and a Sample Frequency of at least 25 KHz.
The distance between the impact location and the sensor should be no larger than 300 mm. Several impacts are applied to the top of the pile. The reflected echos are then recorded for each individual impact. As an alternative, the average can be determined and used. As mentioned earlier, acceleration transducer can be used for the purpose of this test. In this case, the apparatus shall provide signal conditioning and integrate acceleration to obtain velocity. The apparatus shall balance the velocity signal to zero between impact events.