Shovel loader

These are used primarily to excavate earth and load into hauling units such as trucks or tractor pulled wagons or in conveyer belt etc. Shovels can be used to excavate all type of soils except hard rocks without prior loosening.

The quantity of materials that can be hauled by the loader depends upon its bucket capacity. Loader bucket capacities are specified by the manufacturer either in terms of heaped capacity or struck capacity. However, planning can be based on the loose soil struck capacity of the bucket, and the heaped capacity (loose soil) can be converted into struck capacity (loose soil) as under:

Bucket struck capacity = bucket heaped capacity X fill-factor

Type of shovels  

Shovels can be divided into the following groups:

1. Crawler mounted shovels

2. Tyred mounted shovels

3. Self-propelled shovels

4. Non self-propelled shovels.

batteries Shovel loader

Preparation of a Cost Analysis

         

Preparation of a cost analysis

The primary purpose for using cost analysis of construction project provides useful source of cost information.  Any form of cost analysis should be provided in standard way with the following.

Information on the total project

Summary of element costs with preliminaries shown separately and also apportioned among the elements

A brief specification in element form

Sketch plans and elevations for the project

The amplified analysis

Information of the total project is important as it includes the building type which is necessary for future analytical purpose of a similar type of project. In addition, the client, location, tender date, contract particulars, market conditions, competitive tender list, project details, and brief cost information are provided under project information section of the cost analysis.

The following  basic principles  need to be followed in preparing the cost analysis

The qualitative aspects of the project should be expressed by reference to accompanying specification notes

An element should be of cost significance

The analysis should consider the features in different building which have heavy bearing on cost.

An element should be easily definable and capable of having the appropriate costs allocated against it with a minimum of effort on the part user

Other information relevant to the costs in the analysis should be provided as a background to these data

Construction of Cofferdams

 Cofferdam is a temporary structure built for the purpose of excluding or soil sufficiently to permit construction to proceed without excessive pumping, and to support the surrounding ground.

Construction of foundation is most important in a structure, so all the correct and safe actions should be taken while doing a foundation.

Cofferdam is commonly used for oil rig construction and repair, bridge and dam work, the cofferdam is usually a welded steel structure that is temporary and is typically dismantled after work is completed.

Cofferdams is used to provide a safe working space at foundation level

It’s difficult to handle deep foundations under water or ground in deep

Safety in construction of cofferdams

Construction of cofferdam presents safety problems unique to this type of construction.

They will be limited access, limited work areas, damp or wet footing, and deep excavations.

Provisions must be made for safe access in terms of adequate walkways, rails, ladders, or stairs into and out the lower levels.

The work may be within a waterway, in which case additional safety regulations may apply. These would include provisions for flotation devices, boats, warning singles, and suitable means for a rapid exit.

 

    Inside the Barge Gate Cofferdam

Inspection and Maintenance

Dams should be inspected regularly and immediately repaired if required.  A through inspection should be conducted following flood events.

Water removed from work area may be silty and should be discharged to a

vegetated area at least 30 m from the watercourse, or pumped through a filter bag

The weather forecast should be monitored to anticipate the occurrence of high flow

events.  Work operations should be adjusted to accumulate possible overtopping of

the coffer dams

       Barge Gate Cofferdam

Consideration of Selection of a cofferdam

Soil conditions

Location of the coffer dam (land/water)

Plan size of working area

Maximum depth of soil or water to be retained.

Nature of the permanent or floating structure

Effects on excising adjacent structures

Ground water level & their fluctuation

Construction time

Availability of equipment and material

Possible construction method & dismantling

Effects of noise, vibration and fumes, & fire risk.

It water cofferdam behavior of water.

Cofferdams is mainly of two types

Gravity coffer dam :-

Sheeting cofferdam 

Steel Structure Design methods

Steel structure may be design three methods.

Elastic design

Plastic design

Limit sate design

Elastic design is the traditional method. Steel is almost perfectly elastic up to the yield point and elastic theory is a very good method on which ton base design. Structures are anayesed by elastic theory and sections are sized so that permissible stresses are not exceed. Design is in accordance with BS 449: plastic theory developed to take account of behavior past the yield point based on finding the load that cases the structure to collapse. Then working load is the collapse load divided by a load factor. This too is permitted under BS449.

Plastic design

In plastic analysis and design of a structure, the ultimate load of the  structure as a whole is regarded as the design criterion. The term  plastic has occurred due to the fact that the ultimate load is found from the strength of steel  in the plastic range. 

This method is rapid and provides a rational approach for the analysis of the structure. It also provides striking economy as regards the weight  of steel since the sections required by this method are smaller in size than those  required by the method of elastic analysis. Plastic analysis and design has its  -main application in the analysis and design of statically indeterminate framed  structures.

Limit sate design

A Civil Engineering Designer has to ensure that the structures and facilities he designs are (i) fit for their purpose (ii) safe and (iii) economical and durable. Thus safety is one of the paramount responsibilities of the designer. However, it is difficult to assess at the design stage how safe a proposed design will actually be. There is, in fact, a great deal of uncertainty about the many factors, which influence both safety and economy. The uncertainties affecting the safety of a structure are due to 

 · Uncertainty about loading

 · Uncertainty about material strength and 

 · Uncertainty about structural dimensions and behaviour.

These uncertainties together make it impossible for a designer to guarantee that a structure will be absolutely safe. All that  the designer can ensure  is that the risk of failure is extremely small, despite the uncertainties. 

Aluminium Formwork for High Rise Buildings

Now a day’s Aluminium formworks used to construction for High Rise Buildings. Probably the most versatile modern construction system, aluminium formwork system, which has created new benchmarks in construction.  This produces a lightweight panel with an excellent stiffness to weight ratio, yielding minimal deflections under concrete loading. Once erected, these panels are subjected to a trial erection in order to eliminate any dimensional or on-site problems.

 Aluminium formwork  High Rise Buildings video 

Aluminium formwork can be used reused  more times  with careful handling and good maintenance. One of the biggest advantage of aluminium formworks has its unsur- passed construction speed. Compared to conventional construction procedures, use of aluminium formworks reduces floor completion cycle from 15 days to 4 to 5 days, primarily because of light weight nature enables fast erection and dismantling and simple system of pin & wedge makes the assembly easier. Pouring concrete together for walls, beams and floors and System ensures accuracy of dimensions without need for re-work and uncomplicated system  requiring use of minimum skilled labour.

But, over and above its strong advantages of speed, economy, re-usages and no extra cost, Aluminium Formworks give your construction structure a very high quality finish. High quality finish is possible due to uniformity of panels and precise joints, as it leaves no deflection, creating evenness, eventually adding style and stability.