New technology in earthquake engineering to resist collapsing of the structures

It is the big challenge for the structural engineers to develop earthquake resistance structures.

An Earthquake resistant structure should have the capacity to resist abrupt ground shaking to reduce the damages to the structure.

Though the reinforced Concrete contains sound earthquake resistance capacity of buildings but owing to the substandard mix design of concrete and improper curing the reinforced concrete lost it’s desired compressive strength and it leads to collapsing of structure during an earthquakes.

Recently, a new innovation is launched in earthquake engineering where the curtain of cables is affixed to ground to significantly enhance the earthquake resistance strength of the building.

In these technology threads are used which are created with thermoplastic carbon fibre composite. These threads are fastened and knotted to produce a strong flexible rod which is 90% lighter as compared to reinforcement bars and contain the equivalent strength.

To resist earthquake successfully, these composite rods are fastened & secured from the roof to the ground and set up around the building. Rods are also set up inside the building to make the interior walls stronger.

These Composite threads are formed with textiles so that the rods can expand and pull the structure back in opposite direction to withstand shaking of the structure.

When an earthquake occurs, in case the building is pushed towards left side, the threads or rods located on right side pulls it back to retain the building in exact position and significantly reduces the structural damage and human death.

For online demonstration of this new technology, go through the following video tutorial.

Video Source: TomoNews US

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Published By
Rajib Dey
www.constructioncost.co
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Various types of notations used in the construction of concrete culvert design

The following notations are used in the drawing of concrete culvert design.

With notation, it is possible to make clear communication among various project stakeholders. Notation helps in avoiding mistakes in any construction project.

A’ = The valid contact area of a footing, measuring unit is in square metres
A = A detailing dimension for culverts that contains skewed ends, measuring unit is in mm
B = Depth of the bottom slab of a box culvert, measuring unit is in mm
B = Gapping among adjoining bars with reference to detailing tables, measuring unit is in mm
C = A coefficient that is applied in finding out the quantities of reinforcing bar.
CANBAS = Canadian Bridge Analysis System
c’ = the valid cohesion among the base of the footing and the soil at the ULS, with reference to CHBDC. kPa
CHBDC = Canadian Highway Bridge Design Code, 2000 Edition
CGSB = Canadian General Standards Board
F = Width of footing for open footing culverts, measuring unit is in mm
F1 = A reinforcing bar spacing factor, measuring unit is in mm-1
HULS = maximum factored horizontal reaction at the level of the base of the footing at the ULS, kN
Lc = Culvert length that is calculated the longitudinal axis, measuring unit is in m
OCPA = Ontario Concrete Pipe Association
OMBAS = Ontario Modular Bridge Analysis System
OPSS = Ontario Provincial Standard Specifications
S = Culvert distance that is calculated perpendicular to the longitudinal axis of the culvert, measuring unit is in mm
SLS = Serviceability limit states, in accordance with CHBDC
T = Depth of top slab of culvert, mm tan φ’ effective friction coefficient for concrete cast against soil.
ULS = Ultimate limit states, with reference to CHBDC
V = Unfactored vertical reaction because of the dead load of cast-in-place concrete and soil fill, at the level of the base of the footing, kN
VSLS = Maximum vertical reaction at the level of the base of the footing at SLS, kN
VULS = Maximum factored vertical reaction at the level of the base of the footing at ULS, kN
W = Depth of wall of culvert, measuring unit is in mm
Γ = The extreme angle among the normal to the longitudinal axis and the end of the same culvert, degrees
φ’ = The valid angle of internal friction, with reference to CHBDC, measuring unit is in degrees
θ = Skew angle of culvert, degrees



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Get some useful tips to conduct your leveling survey at home

While going to layout something for road, bridge, dam or pipe line, land surveying plays an important role. Surveying is done to find out the legal boundaries among the parcels of property, the position of current infrastructure, the topography as well as slopes of the land.

Traditional measurement tools like a tape measure and protractor are not suitable for accomplishing large civil structures and public works projects.

In this construction video tutorial, Mr. Grady shows some useful tips which will help you to conduct your own topographic or leveling survey at home with fairly elementary and cost-effective tools. You don’t require any knowledge with sines, cosines, or tangents.

To learn the complete process, go through the following video tutorial.

Video Source: Practical Engineering

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www.constructioncost.co
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Benefits and uses of Light Weight Concrete

Usually, the traditional concrete is made of a heavy material containing density about 2400kg/m3 and strong thermal conductivity. If, the ordinary concrete is used for building up the structure, it can increate the dead weight of the structure and as a result the structure turns out to be heavy. The cost of the structure is also increased significantly.

The light weight concrete is defined as the concrete whose density differs from 300 to 1800 kg/m3.The following methods are applied to build up light weight concrete:

1) By cellular construction.
2) By generating huge quantities of air
3) With the use of no fines concrete
4) With the use of light weight aggregates like expanded clay, shale and slate , fly ash, blast furnace slag etc.

Advantage: The light weight concrete is beneficial for the following reasons :-

a) Because of its low density , it can minimize dead load, enhances the advancement of building and reduces the handling cost.
b) The light weight concrete contains low thermal conductivity. Therefore, in severe atmospheric condition, the type of concrete is mostly recommended.
c) When light weight concrete is used, it provides an opening for industrial wastes like fly ash , slag etc, to get rid of the issue for disposal.
d) It has good resistance capacity against fire.
e) The process for slicing , cutting, drilling or nailing becomes easier for light weight product. It can simplify the construction and repair work.

Uses: Given below, various applications of light weight concrete :-

a) It is extensively utilized as insulator to exterior walls of different types of buildings.
b) It is suitable for erecting load bearing walls, filler wall and partition wall.
c) It is effective for producing pre-cast floor and roof panels and composite walls.
d)It can also be applied for building up in situ composite roof and floor slabs.



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A wide array of reinforced concrete design examples

This construction article is based on various reinforced concrete design examples. You will be familiar with flexural analysis of beam.

Given below, various examples and their solutions :-
Make proper calculation for the following reinforced concrete sections :-

Example 1 : The balanced steel reinforcement: The maximum steel reinforcement area for a tension-controlled and transition section per ACI code 318-11.

The location of the neutral axis and the depth of the equivalent compressive Whitney stress block for the tension-controlled section in B.

Here, the compressive strength is given as f'c = 4 ksi and yield strength is given as Fy = 60 ksi

ACI code 318-11 is followed

Example 2 : Examine the adequacy of a rectangular tension controlled section on the basis of dead and live loads.

A 10 ft long cantilever beam contains a rectangular section and reinforcement. The beam bears a dead load of 2 k/ft (along with self weight) and a live load of 1 k/ft.

The compressive strength is provided as f'c = 4 ksi and yield strength is fy = 60 ksi, verify if the beam has sufficient strength to bear the provided loads with ACI Code 318-11.

Example 3 : Work out the design moment strength and the location of the neutral axis of a rectangular section containing two rows of tension reinforcement.

b (width) is given as 13 inches
d is given as 23.5
h (through depth of the section) is given as 27 inches
dt (distance from the extreme compression fibre to the location of the extreme tension reinforcement) is given as 24.5

f'c (the compressive strength) is given as 4 ksi
fy (the yield strength) is given as 60 ksi

Example 4 : Work out the design moment strength and the position of the neutral axis of a rectangular section with compression reinforcement that yields.

The following properties are included in the rectangular section :-
Width = b = 12"
Effective depth = d = 22.5"
Tension reinforcement = (6) no. 9 bars
Compression reinforcement = (2) no. 6 bars

Compute the design strength of the beam if f'c = 4 ksi and fy = 50 ksi with ACI Code 318-11.

To get the solutions of the above-mentioned problems, go through the following link. www.engineeringexamples.net

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www.constructioncost.co

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How to examine verticality of structure throughout building construction

The verticality works should be examined at the time of building up construction at various stages like during setting up vertical formworks of columns and transmitting levels up successive floors of multi storey structures.

Some useful processes to check verticality of structure throughout building construction
1. Plumb-bob technique
2. Spirit level
3. Theodolite
4. Optical plummet

1. Plumb-Bob Technique: The purpose of this technique is to make sure that constructions are plumb or vertical. It’s application is also found in surveying to set up the nadir regarding gravity of a point in space.

Plumb-bob comprises of a weight with pointed tip on the bottom that is tied to the end of a string. The heavy weight will cling under gravity and produce a precise vertical line that is known as plumb line.

This method is very effective for examining or managing vertical line of structural elements especially indoors like lift shaft. Besides, it is also utilized to check the verticality of foundation, walls, and columns.

The plumb line or vertical line of plumb-bob is affected by wind force and the perfectness is not maintained. It is possible to minimize small to medium lateral movement of plumb-bob efficiently by moistening it in oil or water.

In case the height of structural member is broad, then the string can be substituted with a long wire, but precautions should be plasticized to get rid of imposing risks to the personals functioning under.

2. Spirit Level Method: This tool is used for managing verticality of small scale works; as for instance inspection of formworks and door frames. If spirit level is applied for guess verifications, then it is necessary to examine the verticality with more precise method.

3. Theodolite Method: Theodolite is considerably robust instrument that is utilized to examine verticality works throughout construction providing proper preciseness.

It is useful for examining or managing verticality of towers, wall, foundation and columns specially large number of columns along a one grid line.

The slope can be calculated out of plumb line of the member with Theodolite in conjunction with a tape.

The following methods are utilized to examine column verticality:

Install the digital Theodolite to the center on a peg that is set up 500 mm from the column grid.
Once the Theodolite is installed perfectly the laser beam will be activated and put it to the steel tape that is retained to the formwork.
The reading of the steel tape is captured via the telescope.
Capture the readings of two positions at the equivalent level on both top and bottom levels of the formwork. Any curvature on the surface is easily found by capturing two readings at the same level.

4. Optical Plummet Method: It belongs to an instrument that sight directly down or directly up. Optical plummet contains an automatic compensator that considerably enhances its perfectness with regards to other methods which are applied for managing verticality.



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Combined Pad Foundation Design Spreadsheets

Combined Pad Foundation Design Spreadsheets comprise of a series of spreadsheets which can be used for stability analysis and structural design of a combined rectangular pad foundation.

The spreadsheets evaluate the loadings input by the user and work out the best possible pad size to transmit these loads into an tolerable bearing pressure into the soil.

Unique Pad Sizing and Eccentricity Charts simplify the process for the designer to opt for the best pad dimensions.

As soon as the pad size is set, the spreadsheets then workout the design bending moments and the necessary reinforcement in both X and Y directions for sagging and hogging. The designer can then indicate the perfect reinforcement arrangement with unique recommended reinforcement chart which demonstrates graphically the existing reinforcement arrangements to fulfil both necessary cross sectional area and spacing requirements.

Then a summary page is formed and a reinforcement drawing is produced to provide the perfect reinforcement arrangements which the user has indicated.

The suite comprises of a total of 4 spreadsheets :

• A simple combined pad design spreadsheet to make analysis of a simple combined pad foundation depending on two axial loads where the consequential load must operate through the centroid of the base.

This spreadsheet is ideal for most cases and facilitates making design rapidly for straight forward situations.

• A complex integrated pad design spreadsheet that can easily analyze any combined rectangular pad foundation on the basis of axial, horizontal or moment loadings.

These spreadsheets contain all the tools to design complicated issues or where close attention should be given to detail. It can deal with any size rectangular pad and rectangular columns to where space is restricted in one direction. The spreadsheet also arranges the base for being loaded eccentrically in any arrangement required by the designer.

It comprises sliding analysis to rationalize any horizontal loads. It involves design charts to make brief analysis of shear and punching shear loads, and comprises of bending moment and shear force diagrams to facilitate the designer to design the reinforcement in as much detail.

Both simple and complex spreadsheets are available to abide by either British Standards BS8110 & BS8004 or Eurocodes BS En 1992 & BS En 1997.

Download Combined Pad Foundation Design Spreadsheets civilweb-spreadsheets.com



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How to check quality of concrete in jobs site

The following precautions should be taken during preparation of good quality concrete:

To build up a quality, durable and strong structure, the concrete that is used should contain standard quality. A good quality concrete should be stable, condensed, workable and cost-effective.

The following properties should be maintained to produce a good quality concrete :-

1. The quality of aggregate should have been rigid and long-lasting.

2. The grading of the aggregates should be done perfectly and consistently.

3. Adequate quantities of cement should included in concrete to maintain necessary strength and water-resistance capability.

4. The water does not contain any organic or deleterious materials.

5. The quantity of water should be maintained in such a manner so that the uniformity is retained properly.

6. The proportion of water-cement should keep as minimum as possible.

7. To keep up conformity, mixing of concrete should be performed systematically.

8. To eliminate air bubbles and voids, the freshly arranged concrete should be compacted properly.

9. While transmitting the concrete to the job site, no segregation of or separation of materials should happen in concrete.

10. Concrete that is provided at the point of placing should have been homogeneous & contain right symmetry.

11. Ensure that the concrete is not thrown from a distance of high point to prevent segregation.

12. Curing of concrete should be done perfectly for minimum 28 days.

13. The temperature of concrete should be retained over the freezing point unless it gets rigid enough.

14. It should be stored in even horizontal layer having invariable thickness. Concrete should fill each section in this form.

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What should be the qualities for becoming a successful civil engineer

In order to become a successful civil engineer, the following qualities are essential :-

1. TESTS OF BUILDING MATERIALS: An efficient civil engineer should be well versed with various test methods of building materials. Given below, the details of some crucial test methods :-

Concrete Test: Slump test, compression test, split tensile test, soundness etc.
Soil Test: Core cutter test, compaction test, sand replacement test, tri axial test, consolidation test etc.
Bitumen Test: Ductility test, softening point test, gravity test, penetration test etc.

2. EXAMINATION OF SOIL: Prior to build up a construction, different types of soil tests are accomplished to define the settlement and constancy of soils. Therefore, as a civil engineer, one should possess adequate knowledge with these tests to carry on at the job site.

3. APPLICAIONS OF SURVEYING INSTRUMENTS: Each civil engineer should have clear conception on how to apply various surveying instruments like the total station, theodolite etc. These instruments are specifically designed for marking and measurements.

4. STANDARD CODES USED IN CONSTRUCTION: Each country should contain their standard safety specifications (eg: Is Code) for construction associated works. The construction works of new buildings should abide by the rules and processes indicated in the standard codes. if not, there are chances for collapsing of the structure any time.

5. BAR BENDING SCHEDULE: Bar bending schedule is a vital chart for civil engineers. It offers the reinforcement calculation of RC beam like cutting length, type of bending, the length of bending etc.

6. DRAWING AND DESIGN: Drawing and design are considered as the elementary part of a running project. It offers all the necessary specifications of that project. Each site engineers should possess the quality for evaluating such drawings and designs.

7. COMPUTATION AND BILLS: A civil engineer should have the skills to produce the estimation and bills in a construction project.

8. QUALITY CONTROL: With proper quality control, the profit of the project is raised and the cost is decreased. Therefore, a engineer should be well versed with quality control process.

9. ON SITE MANAGEMENT: A engineer should have adequate knowledge with form-work, concreting, safety measures etc.

10. COORDINATION WITH LABOR: As a civil engineer, one should know how to manage the labors in a job site.



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Why reinforcement is provided in a column

Concrete is strong at bearing compressive stress. Plain concrete can sustain compressive loads capably. But it is always recommended to utilize the R.С.С. columns in place of plain concrete columns in modern day structures for the following reasons :-

Temperature stresses are formed in Concrete because of differences in weather. Cracks may happen for this stress. To get rid of the issue and reduce cracks, some steel is provided at the face of the concrete.

Columns specifically slender columns are prone to lateral loads and moments. Sometimes, tensile stress may also build up particularly in columns at exterior boundary of the building. Steel can deal with this tensile stress.

While making the design of RCC structures, the reinforcement is provided in beams to tie them securely with beams.

Reinforcement is provided so that the size of the columns is not increased.

Reinforcement steel improves the ductility of the member so that the structure gets the ability to withstand earthquake in a superior way.

In R.C.C. columns, less area is required with regards to a plain concrete column It is found that steel can bear load m-times that of concrete of the similar area. To deal with a specific load, the section of an R.C.C. column will be much finer as compared to that of plain concrete. By applying R.С.С. columns, huge space is saved since the size of the column will be less.

A minimum area of steel should be arranged in the column if any case it is necessary for bearing load or not. It is performed to withstand tensile stresses which occur because of eccentricity of loads.

Two types of reinforcements are arranged in a R.C.C. column.

a. Longitudinal reinforcement.
b. Transverse reinforcement.

Longitudinal Reinforcement: The longitudinal reinforcement comprises of steel bars which are arranged longitudinally in a column. It is also known as main steel. The properties of longitudinal reinforcement are given below:

i. To distribute the compressive loads along with concrete, consequently minimizing the size of the column on the whole and parting more usable area.
ii. To withstand tensile stresses which are formed because of any moment or accidental eccentricity.
iii. To yield ductility to the column.
iv. To lessen the impact of creep and shrinkage because of continuous constant loading applied for a long time.

Transverse Reinforcement: The transverse reinforcement is arranged along the lateral direction of the column in the shape of ties spirals which cover the main steel. The function of transverse steel are as following -

i. To retain the longitudinal bars in exact place.
ii. To resist buckling of the main longitudinal bars.
iii. To avoid diagonal tension that happens because of transverse shear formed due to any moment or load.
iv. To yield ductility to the column.
v. To resist longitudinal splitting or bulging from concrete by enclosing it in the core.



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Civil Engineering Retaining Wall Design Spreadsheet

A retaining wall refers to a structure designed and built to combat with the lateral pressure of soil once a desired alteration occurs in ground elevation that surpasses the angle of repose of the soil.

The active pressure enhances on the retaining wall in proportionate ratios from zero at the higher grade level to a highest value at the lowest depth of the wall. In order to become functional, retaining walls should be reinforced properly.

Civil Engineering Retaining Wall Design Spreadsheet can be useful to design a retaining wall through an easy to follow process. The spreadsheet consists of tabs to work out stability, moment and shear, reinforcement etc.

A good quality retaining wall design spreadsheet comes with simple interface & various options that can simplify the design process for retaining wall to a great extent. You can download this spreadsheet for free from the below link.

Download Civil Engineering Retaining Wall Design Spreadsheet

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Basics of Construction Engineering

Construction engineering is a significant sub-discipline. It is included in of civil engineering which has several applications. www.brighthubengineering.com has published this.

It has several applications and it is being applicable across the globe.

The construction activity is the main reflector of the country’s economy.

Construction Engineering

This profession engages several things:

• Construction
• Structure
• Transportation
• Environmental engineering

These all things are related to construction civil engineering and planning, execution as well as management.

Technique: The civil engineering techniques caught up in the construction sector engineering consists of survey, cost estimation and scheduling. The assurance to check the quality is also very important.

Applying modern method:-

• Brickwork is being slowly put back by concrete blocks,
• Porous real blocks are being used for pavements and landscaping.
• Ready mixed concrete is obtainable
• Padding Concrete Formwork is a current system in structure design
• With the rising cost of land, the obligation to construct buildings on utmost covered area on the same piece of land has become significant.

Design:- The importance of design in a building is utmost important. It is really a backbone. It looks after safety, cost and other important factor like environment.

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