October 2011 – Civil Engineering Projects

Height of Collimation and Rise and Fall Method | Methods of Levelling

October 30, 2011 by Designer

Methods of Levelling | Guide to Surveying and Levelling

In this article, we will discuss two important methods of Levelling. We will also study these Methods with the help of Numerical Examples in our successive articles.

There are two Methods of Levelling:

Height of Collimation Method
Rise and Fall Method

Height of Collimation Method

This method is simple and easy.

Reduction of levels is easy.

Visualization is not necessary regarding the nature of the ground.

There is no check for intermediate sight readings;

This method is generally used where more number of readings can be taken with less number of change points for constructional work and profile levellings.

Principles of Chain Surveying or Linear Surveying | Civil Engineering

October 30, 2011 by Designer

Chain Surveying or Linear Surveying | Surveying and Levelling

It is the method of land surveying in which only linear measurements are made.

Chain surveying requires chain, tape and ranging rods.

Chain surveying is not suitable for large areas having many details.

(The term “details” means a natural or manmade features at or near the ground surface).

It consists of the following:

Hard details

Hard details include buildings, roads, walls etc.

Soft Details

Soft details include river, vegetation, trees etc.

Overhead details

Overhead details include power and telephone lines.

Underground details

Underground details include survey of water mains, sewer etc.

Principles of Chain Survey

A triangle is a simple figure which can be plotted from the lengths of three sides even if the angles are not known.

In chain survey, the area to be surveyed is divided into a framework consisting of triangles.

Guide to Doubly Reinforced RCC Beam Design

October 30, 2011 by Designer

RCC Beams

RCC beams are cast in cement concrete reinforced with steel bars. Beams resist compression and tensile forces and add rigidity to the structure.

Beams generally carry vertical gravitational forces but can also be used to carry horizontal loads (i.e., loads due to an earthquake or wind). The loads carried by a beam are transferred to columns, walls, or girders, which then transfer the force to adjacent structural compression members. In light frame construction the joists rest on the beam.

In this article, we are going to discuss types of beam construction and RCC design of simply supportedreinforced beam.

Simply supported RCC beam construction is of two types:

Singly reinforced beam
Doubly reinforced beam

The Magnificient Victoria Tower, Stockholm, Sweden

October 30, 2011 by Designer

Sweden is one of the most prosperous of Scandinavian nations in Europe. It has a long history of traditions and cultural heritage. Sweden is famous for its amazing Swedish Cheese. Stockholm is a beautiful city, and its latest jewel would be the new Victoria Tower. It would be the second highest building in Stockholm after the Kaknästornet.

The Magnificient Victoria Tower, Stockholm, Sweden

The name “Victoria” comes from’ the crown-princess of Sweden. Construction on this tower began in May 2009. There was a lot of debate about the final height of the building. This tower would be operated by Scandic Hotels.

Is it possible to construct an Earthquake-proof building?

October 30, 2011 by Designer

Rapid violent shaking of the Earth’s surface caused by rapid movement of the Earth’s rocky outer layer is known as an Earthquake. Earthquakes occur when energy stored within the Earth, usually in the form of strain in rocks, is suddenly released. Elastic Rebound Theory lays down the phenomena that causes earthquakes. It is mostly related to slippage of active fault-lines in the earth’s crust.

Earthquake Effects on Buildings

The motion along the fault is accompanied by the gradual buildup of elastic strain energy within the rock along the fault. The rock stores this strain energy like a giant spring being slowly tightened.

Methods for Correcting the bearings affected by Local Attraction

October 30, 2011 by Designer

Local Attraction | Methods for Correcting the bearings affected by Local Attraction

The deflection of a magnetic needle from its true position due to the presence of magnetic influencing material such as iron ore, magnetic rock, underground pipeline, electric cables, iron pipes, electric poles in its vicinity is called “Local Attraction”.

Methods of Correcting the bearings

There are two methods of correcting the bearings affected by local attraction:

Included angle Method
Error Computation

Included angle Method

In this method, the included angles of the traverse are calculated first, then starting from the line which is unaffected by local attraction and using the included angles, the corrected bearings of the traverse are computed.

Error Computation Method

In this method, the direction and the amount of local attraction at each survey station is determined.

Then starting from the line which is unaffected by local attraction, the corrected bearing of the traverse are computed.

This method is more accurate than the included angle method.

Hence it is adopted by most of the surveyors.

Foundation Damage and Retrofitting

October 29, 2011 by Designer

Causes of Foundation damage leading to Retrofitting

In one of my previous articles, we discussed various steps in which the survey of the foundation has to be done in order to be considered for retrofitting.

In this article, we will discuss various reasons or causes for the damage of the foundations.

Types of foundation damage can be classified as follows:

Erosion

Rot

Insects

Moisture damage

Settlement in the ground

Specifications for RCC Construction | Building Estimating and Costing

October 29, 2011 by Designer

In my earlier articles, I have discussed types of specifications and various purposes for which specifications are to be given. Most of the constructions of various types of buildings are RCC constructions. In this article, we are going to discuss in detail about the specifications that are to be necessarily given for carrying out RCC (reinforced Cement Concrete) constructions.

RCC Specifications

Shuttering shall be done using seasoned wooden boards of thickness not less than 30mm.

Surface contact with concrete shall be free from adhering grout, nails, splits and other defects.

All the joints are perfectly closed and lined up.

The shuttering and framing is sufficiently braced.

Nowadays timber shuttering is replaced by steel plates.

All the props of approved sizes are supported on double wedges and when taken out, these wedges are eased and not knocked out.

All the framework is removed after 21 days of curing without any shocks or vibrations.

All reinforcement bars conform IS specifications and are free from rust, grease oil etc.

The steel grills are perfectly as per detailed specifications.

The covers to concrete are perfectly maintained as per code.

Bars of diameter beyond 25mm diameter are bent when red hot.

The materials proportion should be as per the specifications of the concrete.

Number of Cement bags required for a specific cement concrete ratios

For cement concrete of ratio 1:1:2(1 cement:1sand/coarse sand:2graded stone aggregate) require 11no bags of 50kg.

For cement concrete of ratio 1:1.5:3 require 7.8no bags of 50kg.

For cement concrete of ratio 1:2:4 require 6 no bags of 50kg.

For cement concrete of ratio 1:3:6 require 4.25no bags of 50kg.

For cement concrete of ratio 1:4:8 require 3.2 no bags of 50kg.

For cement concrete of ratio 1:5:10 require 2.50 no bags of 50kg.

For cement concrete of ratio 1:6:12 require 2.25 no bags of 50kg.

New trends in the Color schemes and Materials of Design

October 29, 2011 by Designer

New Trends in the choice of Color schemes

The new trends in Furniture design has brought a concept of new choice of color schemes depending on the type of ambiance to be created. Along with maintaining the aesthetic aspect, new materials and new lighting techniques have also come up.

Two trend streams emerge; one following the ‘international’ look of pale sophistication, with beiges, creams and white, offset by stark black. A parallel stream throws into focus the bright new color palette with the nouveau chic fuschia, lime green, aubergine and aqua.

The trade and architect community notice a bifurcation in usage with designers selecting the former for more elegant, more ‘serious’ spaces such as offices, or for general use spaces such as lounge areas in hotels, while residential spaces, use color to project the personality of the owners. The bright colours give a happy office look. Finance and Insurance offices are serious and very professional offices can have lighter colors that add richness to the space whereas other offices could use shades of yellow and light brown.

Types of Ranging | Chain Surveying

October 29, 2011 by Designer

Methods of Ranging in Chain Surveying | Guide to Surveying and Levelling

In measuring a survey line, the chain has to be laid out on the ground between the stations.

If the line is short, the chain could be put in alignment easily but if it is long or the end station is not clearly visible, then intermediate points has to be established in line with end points to know the directions of the line by ranging.

Types of Ranging

There are two types of ranging:

Direct ranging
Indirect ranging

Direct ranging

Direct ranging is possible when the stations are intervisible.

Ranging is done by eye-judgement. Ranging rods are erected vertically beyond each end of survey line.

The surveyor stands 2m beyond the ranging rod while the assistant folds the ranging rod vertically in the intermediate stations.

The ranging rod is held roughly in line by the thumb and fore-finger.

The surveyor directs the assistant to move the rod to the left or right until the three ranging rods appear to be in a straight line.

To avoid errors due to the ranging rods not being vertical, the lower end of the rod are cited for alignment.