How to Determine the Size of a Temporary Site Office for a Construction Site

Temporary Site Office / Accommodation

The type of temporary site office/ accommodation to be provided on site is a matter of choice. The contractor can use timber framed huts, prefabricated cabins, mobile offices or even caravans. Generally, separate offices should be provided for the different categories of site staff.

The minimum requirements for construction of this types of office/accommodation is governed by the offices, shop and railway premises acts 1963

Calculation of Office Size  on Construction Site (example)

This example is the calculation of size of building for 6 persons

Assumptions.

Let’s assume an internal height of building of 2.4m,

3.7m2  minimum per person, and 11.5m3 per person.

Office width of 3m.

Calculation

For 6 people, minimum area = 6 x 3.7 =22.2 m2

Similarly;

Minimum volume space= 6 x 11.5 = 69 m3

Since we have assumed the height of building as 2.4m and width as 3m, we can determine the minimum length of building by dividing ;

Minimum volume space/ (height x width) of building;

69/ (3 x 2.4)= 9.58m or say 10m (for 6 persons)

As a check ; 3 x 10 = 30m2 which is greater than 22.2m2

Design Requirements for Reinforced Concrete Masonry as per IS codes.

Masonry Unit.

Minimum compressive strength of masonry units used in reinforced masonry shall not be less than 7Mpa. Steel reinforcement of grade Fe 415 or less shall be used

Concrete.

At least M20 grade concrete should be used.

Minimum cover for steel reinforcement is 15mm top and bottom cover; 20mm for side cover.

Mortar Bed.

High strength mortars H1 or H2 shall be used in mortar bed.

Structural Continuity.

Where floor transfer horizontal forces to wall, there must be proper anchorage of steel reinforcement from floor to wall reinforcement.

Effective Span.

For simply supported/continuous members the smaller of;

  • Distance between centers of supports.
  • Clear distance between supports plus and effective depth, d.

For cantilever; the greater of;

  • Distance between the end of the cantilever and the centre of support.
  • Distance between the end of the cantilever and the face of support plus half its effective depth whichever is greater.

Slenderness Ratio. Walls/Columns.

Ratio of effective height Hef to effective thickness Tef for walls should not exceed 27. For columns; 20

7 Popular Commercial Civil Engineering Software

You are a Civil Engineer or Civil Engineering student, and you are asking yourself; ” of all the civil engineering softwares out there, which ones can I study/purchase?. Well this article is for you. I will be dividing the list of software into 2 sections. The first section for general 2D & 3D Modelling/ drafting/ design and the second section for structural modelling, calculation and design. Here are Popular  commercial civil engineering software you can buy to enhance your understanding and productivity

SECTION 1  General 2D & 3D Modelling/ drafting/ design software.

AUTOCAD

Autocad is a general technical drawing software made by Autodesk. It is very good for creating 2D drawings.You can easily produce all types of building/civil engineering drawings with this great software. This software is worldwide industry standard. In fact, you must have and learn it!. It is quite expensive but there are cheaper versions like the Autocad LT.

You can also get a free one year license on Autocad, check out this OFFICIAL AUTODESK WEBSITE for details.

REVIT

Revit is a coordinated 3D / 2D modelling software great for creating Civil engineering and architectural drawings. It is a BIM software, that is; Building Information Modelling  software.With this software, you start modelling in either 2D or 3D but actually you are modelling in 2D and 3D at the same time. This is the no. 1 software for Architects. It is an Autodesk product which means you can get a free one year license or try it for 30 days.

CIVIL 3D

Civil 3D  is a software for creating various types of civil engineering drawings. It is also owned by Autodesk.You can produce 2D and 3D drawings with this great software. Types of drawings you can produce with this software include;

Building plans, survey plans, site design drawings, rail design drawings, contour drawings, road/highway design drawings, drainage system drawings, city master plans, maps, and much more. 

For pricing of Autocad, revit civil 3D and other Autodesk products, you can check their PRICES HERE. All Autodesk software come with 30 day free trials. If you are eligible you can also get a one year free student of educator license.

SECTION 2. Structural modelling, calculation and design software

CSC ORION

CSC orion is a reinforced concrete structural and design software. It automates the design of concrete buildings from start to finish. It can design any shape of reinforced concrete structure and supports a lot of building codes. CSC orion is now part of Tekla. Telka is company that produces civil and structural engineering software. For more information visit Telka Website

PROKON

Prokon is a software for the automated analysis, design and detailing of a wide range of structures. You can use the software to design reinforced concrete, timber and steel structure. Prokon is popular and used in over 80 countries. You can try prokon software free for 30 days.  Click HERE for pricing.

QUICK STRUCTURE.

Quick structure is a software that automates the analysis, design and detailing of reinforced concrete structures. It can automate the production of calculation sheets and final drawings into drawing sheets. It very easy to use and much cheaper compared to other software listed so far. Click HERE for pricing.

STAAD PRO.

STAAD Pro is a software for the analysis and design of any type and size of structure.It can design steel, concrete, timber, aluminum, and cold-formed steel structures using over 90 international design codes. Click HERE for pricing.

There are many other civil engineering softwares out there that are very good. The ones highlighted in this article is based on their popularity and age.

The Natural and Built up Environment as it relates to land Acquisition.

A built up Environment (Courtesy Google Maps)
A built up Environment (Courtesy Google Maps)

There are many economic  factors to consider before a decision is taking on land acquisition in a particular location. A proper knowledge of the environment, government/vendor restrictions is essential in order to avoid pitfalls.

What is a natural environment ?

A natural environment is an environment that has not been tampered by the actions of man. On the other hand, a built up environment is a natural environment that has been changed considerably by man’s action.

In a natural environment you will often see vegetation including various sizes of trees, wildlife, natural waterways, and rocks. But in a built up environment man alters the natural environment to build houses, roads, water conductors and so on.

Natural and built up environment as it relates to acquiring of a landed property.

The acquiring of a landed property will usually precede the construction of a building on it. The location of the land is important as it has a considerable effect on the cost of the building.

It may cost more to acquire a landed property in a built up environment however, the presence of access roads, water and electricity would make the building constructed economically viable.

On the other hand it may cost less to acquire a land in a more natural or less developed environment but may cost more to build and use the building. This is because this kind of environment is characterised by undeveloped roads, thick vegetation, limited or lack of social amenities.

Other environmental considerations include;

  • Town Planning requirements and building regulations
  • Land restrictions by vendor
  • Adjoining buildings or land
  • Use of building
  • Daylight and view aspects

The physical features around or within the land property should also be taking into consideration. Things to be look out for include:

Land level; is the land level or is it slope. If sloped how steep is it. It may usually cost more to build on a land that is sloped.

Vegetation: how intense is the vegetation?, How many trees are present and how big?. Considerable amount may be spent on removal of vegetation.

Condition of soil: what type of soil is present?, is it swampy, clayey, waterlogged, rocky, sandy etc. these may have a considerable impact on cost of foundation for the building.

Other physical conditions include;

  • Size of land
  • Natural waterways, lakes, ponds, streams and rivers.
  • Approach and access roads
  • Shape of land
  • Services available
  • Climatic conditions
  • Restrictions such as right of way, tree preservations

Design steps to be followed for an Unreinforced Masonry Wall as per IS 1905(1987)

Here are the design steps to be followed for an unreinforced masonry wall.

  1. Estimate the self weight and imposed loads. See IS 875 part 1&2 on how to go about it.
  2. Estimate the eccentricity ratio taking moments about the centerline of the wall. You can use the equation stated below to calculate eccentricity ratio. WE=w1e1+w2e2 where W is the weight of the masonry wall and E is the eccentricity. Eccentricity ratio is E divided by thickness of the wall.
  3. Estimate the effective height, length and thickness of the wall.
  4. Calculate slenderness ratio as the lesser of the 2; effective height / effective thickness or effective length / effective thickness.
  5. With the eccentricity and slenderness ratios; estimate the stress reduction factor from the code . If necessary you can also estimate area reduction factor and shape modification factor.
  6. Calculate the compressive stress of the wall based on the wall load. Then divide by stress reduction factor, to arrive at the basic compressive stress required.
  7. Apply increase in  basic compressive stress if eccentricity is significant. Increase of up to 25% is allowed by the code
  8. With the help of TABLE 8 of the IS code 1905,and using the basic compressive stress, chose the appropriate unit strength and mortar mix required.

Introduction into seismic design of buildings.

This article was written based on Indian building codes.

Response reduction factor R for buildings in seismic design.

In the seismic design (earthquake) of masonry structures, design forces can be reduced by an R factor for seismic design. This factor is called response reduction factor. The R factor depends on the type of structure. Generally the R values are lower for unreinforced masonry structures and higher for reinforced masonry structures. For R factor related to the type of structure you are designing, consult the building code. In seismic zones or zones prone to earthquakes, the building code will specify the general requirements and type of building to be built.

Seismic weight.

 Seismic weight is the weight of the building that will participate in developing inertial forces during an earthquake. That is the calculated weight based on dead and live loads that will participate in the event of an earthquake.

Importance factor (I) in seismic design

Similar to the response reduction factor, importance factor is also used to adjust the design forces used in seismic design. The I factor increases based on how important the building is. The I  factor is based on whether the building is public or private. For the same kind of building the I factor is increased for public buildings. This is because there is tendency for much more people to be on this type building at the same time.

Design seismic coefficient (Ah)

The design seismic coefficient is calculated based on several factors. These factors are; seismic zone factor, response reduction factor, importance factor and spectral ratio.

As per the Indian building code, Seismic coefficient ;

Ah =(Z/2)(Sa/g)/(R/I) .

Z is seismic zone factor, Sa/g is spectral ratio, R is response reduction factor and I is importance factor.

General requirement for buildings to resist seismic vibrations.

  • Slenderness of the building should be limited as much as possible. This should reduce the possibility of bulking under vertical loads.
  • Building should provide adequate stability against overturning from horizontal forces.

The above points can be achieved if the building is properly designed and adequately  braced using beams, columns, cross walls and buttresses where appropriate.