QS World University Ranking Best Civil and Structural Engineering School In The World For 2011

MIT tops the first ever QS World University Ranking® for Civil and Structural Engineering, which also sees a top-five performance from Imperial College London and two Asian universities in the top ten.

A diverse top 20 features nine universities from the US, three from the UK, two from Singapore, and one apiece from Japan, Switzerland, Australia, the Netherlands, China and Canada.

Below is the Top 20 Universities in the World for Civil and Structural Engineering:

1. Massachusetts Institute of Technology (MIT) United States
2. Stanford University United States
3. University of Cambridge United Kingdom
4. University of California, Berkeley (UCB) United States
5. Imperial College London United Kingdom
6. University of Oxford United Kingdom
7. National University of Singapore (NUS) Singapore
8. The University of Tokyo Japan
9. California Institute of Technology (Caltech) United States
10. ETH Zurich (Swiss Federal Institute of Technology) Switzerland
11. The University of Melbourne Australia
12. University of Illinois at Urbana-Champaign United States
13. Delft University of Technology Netherlands
14. University of California, Los Angeles (UCLA) United States
15. University of Texas at Austin United States
16. Cornell University United States
17. Tsinghua University China
18. Nanyang Technological University (NTU) Singapore
19. University of Michigan United States
20. University of Toronto Canada

Metrics for the selection are its contribution to the Academe, Rate of Employment, and its Citations received.
For the Complete List, read this site.


What Are The Testing Procedure Organization In USA For Civil Engineering Projects?

Numerous organizations that are involved with the construction industry have testing as part of their specifications. Below is a list of those special organizations (not inclusive).

These organizations have set up procedures for testing every component on a construction site. The architects and consultants that have developed the contract drawings and specification usually include in these documents the tests that are required for the project.

These testing procedures are taken from the organizations listed in the list. In the urban environment, the local, state, and municipal governments have established additional testing requirements that must be followed.

In a majority of cases, outside testing laboratories are used to determine the capability of the components. The testing laboratories used should be completely independent from the party requesting the tests and are usually retained by the owner.

The names of the local testing laboratories can be obtained through the Internet, local yellow pages,
local contractors, or municipal agencies.

The following is a list of organizations (not inclusive) that have testing as part of
their specifications:

1. ACI (American Concrete Institute)—
2. AISC (American Institute of Steel Construction)—
3. ASTM (American Society of Testing and Materials)—
4. NEC (National Electrical Code)— 7008SB&src=nfpa&order_src=A292
5. ASHRAE (American Society of Heating Refrigeration Air Conditioning
6. IBC (International Building Code)—
7. NFPA (National Fire Prevention Association)—
8. UL (Underwriters Laboratories Inc.)—

9. Local building codes—Will vary depending upon location
10. ANSI (American National Standards Institute)—
11. AWS (American Welding Society)—
12. SMACNA (Sheet Metal and Air Conditioning Contractors National
13. ASME (American Society of Mechanical Engineers)—
14. SIGMA (Sealed Insulating Glass Manufacturers Association)—401 N. Michigan
Ave., Suite 2400, Chicago, IL 60611; (312) 644-6610
15. AAMA (American Architectural Manufacturers Association)—
16. FM (Factory Mutual)—
17. NEMA (National Electrical Manufacturers Association)—
18. NIST (National Institute of Standards and Technology)—
19. PCI (Precast/Prestressed Concrete Institute)—
20. ASCE (American Society of Civil Engineers)—


How To Make Cost Estimates For Civil Engineering Projects?

In carrying out cost management there should be a clearly defined route from feasibility stage through to the placement of a contract. There should be break points, or gateways, when the client can take the decision whether to proceed or not.  This is in line with the recommendations by the Office of Government Commerce in their Gateway Review Process.

One of the benefits of cost management in the pre-contract stage, especially in multicontract projects, is that it helps the project team to better establish the appropriate project contract strategy. That is, which work should be placed in which contract and possibly the form of contract which should be adopted for particular contracts.

Cost management can also help identify possible programme restraints both in contract preparation and execution. The preparation of the first estimate would be based on a variety of techniques, for example, historic data or approximate quantities.

Major projects often have substantial elements that are unique and for which there is no relevant historic data. In these cases it is necessary to analyse the project in as many individual work sections as can be identified, if possible to prepare indicative quantities and consider the resources necessary to carry out the work.

During this indicative stage it is wise to contact potential contractors and manufacturers especially with
regard to order-of-cost estimates for specialist sections.

Other matters that have an effect on cost and need to be addressed at this time include location of project and access thereto, especially with regard to heavy and large loads, availability of labour and the possible need for residential hostels or other accommodation for workmen, off-site construction, temporary works. It will also be necessary to consider allowances for design development, allowances for consultants’ fees and client’s costs, land-acquisition costs and general contingencies.

When the client has accepted the first estimate and instructs that the project proceed to the next stage, then this becomes the first cost plan against which further design developments and changes are monitored.

During the process of design development the main duties of the quantity surveyor as part of the cost management team are as follows: to check and report the cost of design solutions as they are established or refined by the engineers;  to prepare comparative estimates of various design solutions or alternatives and advise the engineer accordingly;  as changes are introduced into the project, to estimate the cost effect of the change and to report;  to prepare a pre-tender estimate based on a bill of quantities (BofQ) or priced activities;  to prepare a financial appraisal.

The monthly issue of the updated cost plan is the vehicle whereby the cost management team is made aware of the current estimated cost of the project. In its simplest form a pre-contract cost plan will set out in tabular form each and every work section, the approved estimate for that section, the estimate for the previous and the current month for the section and a note of the changes that have taken place in the month. The total of all the sections provides the estimated cost of the project.

There should be a continuous dialogue between the designers and the quantity surveyor (QS); ideally both should work together in the same office during the critical stages of design development. Normally, there are so many changes within a month during design development that these are better listed as an appendix to the cost plan.

One national client insists that a separate appendix to the cost plans lists all potential changes and these have to be approved by his project manager before changes can be included in the cost plan. In this way the cost plan represents committed cost only (Shrimpton, 1988).

The extent of detail in the preparation and updating of cost plans is such that it is best handled on a database for transfer to a spreadsheet.

The accepted estimate in the form of priced activities or BofQs becomes the basis for the first post-contract cost plan. This then acts as the client’s design datum for cost management and reporting in the construction stage.


What Are The Different Types Of Modified Portland Cements?

Increasingly, modern concretes contain a blend of Portland cement and other cementitious materials. When other materials are added to Portland cement at the time at which the concrete is batched, they are referred to as mineral admixtures; however, there are also hydraulic cements, which are produced either by forming other compounds during the burning process or by adding other materials to the clinker and then intergrinding them.

The common types of such modified cements are described in the following sections.

Portland Pozzolan Cements
Portland pozzolan cements are blends of Portland cement and a pozzolanic material. The role of the pozzolan is to react slowly with the calcium hydroxide that is liberated during cement hydration.

This tends to reduce the heat of hydration and the early strength but can increase the ultimate strength of the material. These cements tend to be more resistant to sulfate attack and to the alkali–aggregate reaction.

Portland Blast-Furnace Slag Cements
Ground granulated blast-furnace slag (GGBFS), which is a byproduct of the iron and steel industry, is composed largely of lime, silica, and alumina and thus is a potentially cementitious material. To hydrate it, however, it must be activated by the addition of other compounds.

When the GGBFS is to be activated by lime, the lime is most easily supplied by the hydration of the Portland cement itself. Slags may be present in proportions ranging from 25 to 90%. They react slowly to form C–S–H, which is the same product that results from the hydration of the calcium silicates.

In general, because they react more slowly than Portland cement, slag cements have both lower heats of hydration and lower rates of strength gain.

On the other hand, they have an enhanced resistance to sulfate attack. When the GGBFS is to be activated with calcium sulfate (CaSO4), together with a small amount of lime or Portland cement, the material is known as supersulfated cement.

This cement is available mostly in Europe, where it is used for its lower heat of hydration and its resistance to sulfate attack.

Expansive Cements
Expansive cements were developed to try to offset the drying shrinkage that concrete undergoes. This is particularly important when the concrete is restrained against contraction or when it is to be cast against mature concrete in repair situations.

In both cases, severe cracking may occur as a result of the shrinkage. Expansive cements are based on the formation of large quantities of ettringite during the first few days of hydration; however, they are little used today, in large part because it is very difficult to control (or predict) the amount of expansion that will take place for a particular concrete formulation.


What Are Crane Supported Leaders Used In Piling?

Although the complete piling rig with its base frame and leaders supported by a stayed mast provides the best means of ensuring stability and control of the alignment of the pile, there are many conditions which favour the use of leaders suspended from a standard crawler crane.

Rigs of this type have largely supplanted the frame-mounted leaders for driving long piles on land in the UK and USA. The usual practice is to link the leaders by the head of the crane jib and to control their verticality or backward or forward rake by means of adjustable stays near the foot of the leaders.

The latter bear on the ground through an enlarged foot which can be levelled by a screw jack. BSP International Foundations Ltd. TL series leaders (Figure 3.6) have heights of 19.0m and 21.9m and carry hammers of up to 3 tonne mass.

The 610mm and 835mm square section lattice leaders have a height to the cathead of 22.5 and 38m respectively, and can carry combined pile and hammer loads of 13 tonne and 21 tonne respectively.

Backward and forward rakes of up to 1:3 are possible depending on the stability of the crawler crane. There is a practical limit to the length of pile which can be driven by a given type of rig and this can sometimes cause problems when operating the rig in the conventional manner without the assistance of a separate crane to lift and pitch the pile.

The conventional method consists of first dragging the pile in a horizontal position close to the piling rig. The hammer is already attached to the leader and drawn up to the cathead. The pile is then lifted into the leaders using a line from the cathead and secured by toggle bolts.

The helmet, dolly and packing are then placed on the pile head and the assembly is drawn up to the underside of the hammer. The carriage of the piling rig is then slewed round to bring the pile over to the intended position and the stay and angle of the crane jib are adjusted to correct for vertically or to bring the pile to the intended rake.  The problem is concerned with the available height beneath the hammer when it is initially drawn up to the cathead.

Taking the example of leaders with a usable height of 20.5m in conjunction with a hammer with an overall length of 6.4m, after allowing a clearance of 1m between the lifting lug on the hammer to the cathead and about 0.4m for the pile helmet, the maximum length of pile which can be lifted into the leaders is about 12.7m.

A somewhat longer pile could be handled if the leaders were of a type which allows vertical adjustment. Occasionally it may be advantageous to use leaders independent of any base machine. Thus if only two or three piles are to be driven, say as test piles before the main contract, the leaders can be guyed to ground anchors and operated in conjunction with a separate petrol or diesel winch.

Guyed leaders are slow to erect and move, and they are thus not used where many piles are to be driven, except perhaps in the confines of a narrow trench bottom where a normal rig could not operate.


What Are The Problems Of Clay As Foundation?

Special Problems of Clay Soils
The majority of clay soils can cause foundation problems as they slowly change in volume due to increases or decreases in water content. This change is related to the season with the ground expanding in the winter and
contracting in the summer.

This seasonal change, which may be in the order of + or - 30mm at ground level, can affect the clay to a depth of about a metre, with the ground below this level having a fairly stable moisture content.

Where clay soils contain trees the problem is more severe. Trees and heavy vegetation draw a considerable amount of water from the ground during the growing season.

A mature poplar takes up as much as 1000 litres of water per week. In long hot summers with little or no rainfall the tree will continue to draw moisture out of the ground and the clay will shrink.

This, of course, is in addition to the seasonal drying mentioned above. If buildings are sited near individual or groups of trees serious cracking in the walls can occur as a result of ground movement.

To prevent this movement from affecting strip foundations they must be deeper than the tree roots. An alternative, of course, is to site the buildings well clear of the trees.

Where trees have been removed from clay soils the opposite problem occurs. As the ground slowly regains moisture it will expand and this can continue for a period of up to 10 years.

The pressure that dry clay develops when reabsorbing moisture is likely to be greater than that imposed by the building load and upward movement of the structure will occur.

If houses are built on the site before this ground expansion is complete, cracking will occur in the walls and foundations; the swelling will be uneven because it will be concentrated around the removed tree.


What Is The Role Of Project Estimator In Civil Engineering Project?

The estimator for the project will be involved with putting together conceptual budgets, design development budgets, and progress construction document estimates, and preparing the project budgets including subcontractor trade costs, general conditions costs, contingencies, fees, insurances, and analysis of the subcontractors bids.

The estimator must have a full understanding of all aspects of the construction process, the delineation of the work among the subcontractor trades and jurisdictions, cost of construction materials, cost of construction personnel, and appropriate mark ups in order to put together meaningful estimates and budgets for the project.

During the preconstruction phase, the estimator will play a key role in working with the project team to define the project scope, design intent, architectural finishes, engineering systems, specialty items, long lead items, appropriate inflation, and contingency factors to develop a meaningful estimate for the project.

If the estimate is too high or too low, it can significantly affect the feasibility and scope of the project and cause a creditability problem for the CM/GC. The estimator must have a sixth sense and a magic scale to weigh and assess matters to come up with a meaningful estimate for the project, even when there is little documentation from the design team on which to base it.

Estimates during the preconstruction phase of the project are often done on an order of magnitude basis or by cost per square foot, cost per Btu of cooling or heating, and cost per kilowatt of electrical load. Often, allowances may be made where sufficient definition of the exact scope of certain items, such as the lobby, plaza, roof garden, and signage is not available.

In these cases, a target allowance is helpful for the entire project team to manage the design and engineering of the area or system. The estimator will usually work out of the home office during this phase of the project.

During the bid and award process, the estimator will be involved with developing the list of perspective bidders, screening and finalizing the list of bidders, developing bid packages, receiving bids, analyzing and leveling bids, recommending award of subcontracts, and reviewing the bid for completeness, qualification and exclusions, and unit prices.

This is a very important and critical task; if the subcontractor is not scoped out properly and is awarded without a complete project purchase, the amount of change orders and claims thereafter can be significant and have a negative impact on the project. The estimator will usually work out of the on-site project office for all phases of the project.

During the construction phase, the estimator will be involved with pricing change orders for bulletins, sketches, field information memos (FIMs), requests for information (RFIs), and reviewing subcontractor’s claims for extra work as it relates to their contracts.

All allowances that may have been included in a subcontract need to be accounted for and reconciled as the final scope of work and project is defined.

During the project close-out phase, the estimator will be finalizing all subcontractor final contract amounts, including all base contract amounts, approved change orders, adjustment of allowances, back charges, etc. to determine the final contract price for each subcontractor.

You want to be a project estimator? Give us your thoughts and leave a comment. :)


Civil Engineering Free E-Book Download Link

Fully updated and packed with more than 500 new formulas, this book offers a single compilation of all essential civil engineering formulas and equations in one easy-to-use reference.

Practical, accurate data is presented in USCS and SI units for maximum convenience. Follow the calculation procedures inside Civil Engineering Formulas, Second Edition, and get precise results with minimum time and effort.

Each chapter is a quick reference to a well-defined topic, including:

Beams and girders
Piles and piling
Concrete structures
Timber engineering
Soils and earthwork
Building structures
Bridges and suspension cables
Highways and roads
Hydraulics, drams, and waterworks
Power-generation wind turbines
Wastewater treatment
Reinforced concrete
Green buildings
Environmental protection


Civil Engineering Design And Construct - A Guide To Integrating Design Into The Construction Process Free E-Book Download Link

Free E-Book Download Link of Civil Engineering Design And Construct - A Guide To Integrating Design Into The Construction Process

This publication is a guide to best practice in managing the project process in civil engineering design and construct (D&C) projects. It discusses the issues to be addressed when managing design and explains the attitudes and practices that are recommended to enable projects to succeed. 

It is intended to increase awareness and understanding of the issues involved, identifying what decisions need to be made, when and why. Differences between D&C and traditional procurement routes are highlighted along with contractual issues.

"Design and construct" is taken to be a generic term encompassing the whole family of design, construct, finance, own, operate and transfer procurement strategies, in which one party is responsible for both designing and constructing a facility. 

This includes projects procured under the Private Finance Initiative (PFI). Considerable emphasis is placed on imparting awareness of the importance of the designer-constructor interface as, in a D&C project, the most critical lines of communication are at this interface. 

As well as describing contractual frameworks, this guide also contains management toolboxes for reference. It is a working document that will assist those at a senior level (clients, contractors and consultants alike) who have to make crucial decisions affecting the outcome of a project.



What Are Cold Formed Steel Shapes?

A wide variety of shapes can be produced by cold-forming and manufacturers have developed a wide range of products to meet specific applications. Figure 3.11 shows the common shapes of typical cold-formed steel framing members. Figure 3.12 shows common shapes for profiled sheets and trays used for roofing and wall cladding and for load bearing deck panels.

For common applications, such as structural studs, industry organizations, such as the Steel Framing Alliance (SFA) and the Steel Stud Manufacturers Association (SSMA) have developed standard shapes and nomenclature to promote uniformity of product availability across the industry. Figure 3.11 shows the generic shapes covered by the Universal Designator System.

The designator consists of four sequential codes. The first code is a three or four-digit number indicating the member web depth in 1/100 inches. The second is a single letter indicating the type of member, as follows:

framing member with stiffening lips
L = Angle or L-header
F = Furring channels
U = Cold-rolled channel
T = Track section

The third is a three-digit numeral indication flange width in 1/100 inches followed by a dash. The fourth is a two or three-digit numeral indicating the base steel thickness in 1/1000 inch (mils). As an example, the designator system for a 6'', C-shape with 1-5/8'' (1.62'') flanges and made with 0.054'' thick steel is 600S162-54.

Special Design Considerations for Cold-Formed Steel
Structural design of cold-formed members is in many respects more challenging than the design of hot rolled, relatively thick, structural members. A primary difference is cold-formed members are more susceptible to buckling due to their limited thickness.

The fact that the yield strength of the steel is increased in the cold-forming process creates a dilemma for the designer. Ignoring the increased strength is conservative, but results in larger members, hence more costly, than is needed if the increased yield strength is considered.

Corrosion creates a greater percent loss of cross section than is the case for thick members. All cold-formed steel members are coated to protect steel from corrosion during the storage and transportation phases of construction as well as for the life of the product.

Because of its effectiveness, hot-dipped zinc galvanizing is most commonly used. Structural and non-structural framing members are required to have a minimum metallic coating that complies with ASTM A1003/A1003M, as follows:
■ structural members – G60 and
■ non-structural members G40 or equivalent minimum.

To prevent galvanic corrosion special care is needed to isolate the cold-formed members from dissimilar metals, such as copper. The design, manufacture and use of cold-formed steel framing is governed by standards that are developed and maintained by the American Iron and Steel Institute along with organizations such as ASTM, and referenced in the building codes.


What Are Structural Fasteners?

Steel sections can be fastened together by rivets, bolts, and welds. While rivets were used quite extensively in the past, their use in modern steel construction has become almost obsolete. Bolts have essentially replaced rivets as the primary means to connect nonwelded structural components.

Four basic types of bolts are commonly in use. They are designated by ASTM as A307, A325, A490, and A449. A307 bolts are called unfinished or ordinary bolts. They are made from low carbon steel.

Two grades (A and B) are available. They are available in diameters from 1/4 in. to 4 in. in 1/8 in. increments. They are used primarily for low-stress connections and for secondary members. A325 and A490 bolts are called high-strength bolts. A325 bolts are made from a heat treated medium carbon steel.

They are available in three types: Type1—bolts made of medium carbon steel; Type 2—bolts made of low carbon martensite steel; and Type 3—bolts having atmospheric corrosion resistance and weathering characteristics comparable to A242 and A588 steel. A490 bolts are made from quenched and tempered alloy steel and thus have a higher strength than A325 bolts.

Like A325 bolts, three types (Types 1 to 3) are available. Both A325 and A490 bolts are available in diameters from 1/2 in. to 1-1/2 in. in 1/8 in. increments. They are used for general construction purposes.

A449 bolts are made from quenched and tempered steel. They are available in diameters from 1/4 in. to 3 in. A449 bolts are used when diameters over 1-1/2 in. are needed. They are also used for anchor bolts and threaded rod.

High-strength bolts can be tightened to two conditions of tightness: snug-tight and fully tight. Snug-tight conditions can be attained by a few impacts of an impact wrench, or the full effort of a worker using an ordinary spud wrench.


A Tutorials on Shear and Bending Moment Diagram? How To Make Shear and Bending Moment Diagram

In order to plot the shear force and bending moment diagrams it is necessary to adopt a sign convention for these responses. A shear force is considered to be positive if it produces a clockwise moment about a point in the free body on which it acts.

A negative shear force produces a counterclockwise moment about the point. The bending moment is taken as positive if it causes compression in the upper fibers of the beam and tension in the lower fiber. In other words, sagging moment is positive and hogging moment is negative.

The construction of these diagrams is explained with an example given in Figure 2.4.

The section at E of the beam is in equilibrium under the action of applied loads and internal forces acting at E as shown in Figure 2.5. There must be an internal vertical force and internal bending moment to maintain equilibrium at Section E.

The vertical force or the moment can be obtained as the algebraic sum of all forces or the algebraic sum of the moment of all forces that lie on either side of Section E.

The shear on a cross-section an infinitesimal distance to the right of pointAisC55 k and, therefore, the shear diagram rises abruptly from 0 to C55 at this point. In the portion AC, since there is no additional load, the shear remainsC55 on any cross-section throughout this interval, and the diagram is a horizontal as shown in Figure 2.4. 

An infinitesimal distance to the left of C the shear is C55, but an infinitesimal distance to the right of this point the 30 k load has caused the shear to be reduced to C25. 

Therefore, at point C there is an abrupt change in the shear force from C55 to C25. In the same manner, the shear force diagram for the portion CD of the beam remains a rectangle. In the portion DE, the shear on any cross-section a distance x from point D is 
               S = 55 − 30 − 4x D 25 − 4x
which indicates that the shear diagram in this portion is a straight line decreasing from an ordinate of C25 at D to C1 at E. 

The remainder of the shear force diagram can easily be verified in the same way. It should be noted that, in effect, a concentrated load is assumed to be applied at a point and, hence, at such a point the ordinate to the shear diagram changes abruptly by an amount equal to the load.

In the portion AC, the bending moment at a cross-section a distance x from point A isM D 55x. Therefore, the bending moment diagram starts at 0 at A and increases along a straight line to an ordinate of C165 k-ft at point C. 

In the portion CD, the bending moment at any point a distance x from C is M D 55.x C 3/ − 30x. Hence, the bending moment diagram in this portion is a straight line increasing from 165 at C to 265 at D. In the portion DE, the bending moment at any point a distance x from D is M D 55.x C 7/ − 30.X C 4/ − 4x2=2. 

Hence, the bending moment diagram in this portion is a curve with an ordinate of 265 at D and 343 at E. In an analogous manner, the remainder of the bending moment diagram can be easily constructed.

Bending moment and shear force diagrams for beamswith simple boundary conditions and subject to some simple loading are given in Figure 2.6.


What Are The Five Types of Portland Cement?

Portland cement has become the most widely used cement in the world. Portland cement got its name because the cured concrete it produced was the same color as a gray stone quarried in nearby Portland, England.

There are five types of portland cement, each with different characteristics.

■ Type I is a general-purpose cement and is by far the most commonly used, especially in residential work. Type I portland cement is suitable whenever the special characteristics of other types are not required.

■ Type II cement has moderate resistance to sulfates, which are found in some soil and groundwater, and generates less heat during hydration than Type I. This reduced curing temperature can be particularly helpful in large structures such as piers and heavy retaining walls, especially when the concrete is placed in warm weather.

■ Type III is a “high early strength” cement. High early strength does not mean higher strength—only that strength develops at a faster rate. This can be an advantage during winter construction because it reduces the time during which fresh concrete must be protected from the cold. Early strength gain can also permit removal of forms and shoring more quickly.

■ Type IV cement produces less heat during hydration than Type I or Type II and is used only in massive civil engineering structures such as dams, large highway pilings, or heavy bridge abutments. Its strength development and curing rates, though, are much slower than Type I.

■ Type V cement is used in concrete exposed to soil or groundwater that has high sulfate concentrations. This type of cement is usually available only in areas where it is likely to be needed. In the United States, Type V cement is common only in the southwestern states.

Types I, II, and III portland cement can also be made with a foaming agent that produces millions of evenly distributed microscopic air bubbles in the concrete mix. When manufactured in this way, the cements are said to be air entrained, and are designated as Types IA, IIA, and IIIA. Air-entrained cements require mechanical mixing.

Finely ground cement increases the workability of harsh mixes, making them more cohesive and reducing tendencies toward segregation. Coarsely ground cement reduces stickiness. Cement packages that are marked ASTM A150 meet industry standards for both physical and chemical requirements.

Portland cement comes in three colors—grey, white, and buff. The white and buff are more expensive and typically used in commercial rather than residential projects to achieve special color effects.

 Liquid or powder pigments can be added to a concrete mix, and liquid stains can be used to color the surface of cured concrete, but both will add to the cost. For most applications, ordinary gray concrete made with gray cement is suitable. Colored concrete should be reserved for special areas like a front entrance, a patio, or a pool deck


What Are The General Approaches To Fabrication and Erection Of Bridge Steelworks

The objective in steel bridge construction is to fabricate and erect the structure so that it will have the geometry and stressing designated on the design plans, under full dead load at normal temperature.

This geometry is known as the geometric outline.

In the case of steel bridges there have been, over the decades, two general procedures for achieving this objective:

1. The “field adjustment” procedure — Carry out a continuing program of steelwork surveys and measurements in the field as erection progresses, in an attempt to discover fabrication and erection deficiencies; and perform continuing steelwork adjustments in an effort to compensate for such deficiencies and for errors in span baselines and pier elevations.

2. The “shop control” procedure — Place total reliance on first-order surveying of span baselines and pier elevations, and on accurate steelwork fabrication and erection augmented by meticulous construction engineering; and proceed with erection without any field adjustments, on the basis that the resulting bridge deadload geometry and stressing will be as good as can possibly be achieved.

Bridge designers have a strong tendency to overestimate the capability of field forces to accomplish accurate measurements and effective adjustments of the partially erected structure, and at the same time they tend to underestimate the positive effects of precise steel bridgework fabrication and erection.

As a result, we continue to find contract drawings for major steel bridges that call for field evolutions such as the following:

1. Continuous trusses and girders
— At the designated stages, measure or “weigh” the reactions on each pier, compare them with calculated theoretical values, and add or remove bearing-shoe shims to bring measured values into agreement with calculated values.

2. Arch bridges
— With the arch ribs erected to midspan and only the short, closing “crown sections” not yet in place, measure thrust and moment at the crown, compare them with calculated theoretical values, and then adjust the shape of the closing sections to correct for errors in span-length measurements and in bearing-surface angles at skewback supports, along with accumulated fabrication and erection errors.

3. Suspension bridges
— Following erection of the first cable wire or strand across the spans from anchorage to anchorage, survey its sag in each span and adjust these sags to agree with calculated theoretical values.

4. Arch bridges and suspension bridges — Carry out a deck-profile survey along each side of the bridge under the steel-load-only condition, compare survey results with the theoretical profile, and shim the suspender sockets so as to render the bridge floor beams level in the completed structure.

5. Cable-stayed bridges
— At each deck-steelwork erection stage, adjust tensions in the newly erected cable stays so as to bring the surveyed deck profile and measured stay tensions into agreement with calculated theoretical data.

There are two prime obstacles to the success of “field adjustment” procedures of whatever type: (1) field determination of the actual geometric and stress conditions of the partially erected structure and its components will not necessarily be definitive, and (2) calculation of the corresponding “proper” or “target” theoretical geometric and stress conditions will most likely prove to be less than authoritative.


What Are The Properties of Hardened Concrete?

Fully cured, hardened concrete must be strong enough to withstand the structural and service loads which will be applied to it and must be durable enough to withstand the environmental exposure for which it is intended. When concrete is made with high-quality materials and is properly proportioned, mixed, handled, placed, and finished, it is one of the strongest and most durable of building materials.

When we refer to concrete strength, we are generally talking about compressive strength which is measured in pounds per square inch (psi). Concrete is strong in compression but relatively weak in tension and bending.

It takes a great deal of force to crush concrete, but very little force to pull it apart or cause bending cracks (Figure 2-3). Compressive strength is determined primarily by the amount of cement used but is also affected by the ratio of water to cement, as well as proper mixing, placing, and curing.

Tensile strength usually ranges from 7 or 8% of compressive strength in high-strength mixes to 11 or 12% in low-strength mixes. Both tensile strength and flexural bending strength can be increased by adding steel or fiber reinforcement.

Structural engineers establish required compressive strengths for various building elements based on an analysis of the loads which will be applied and the soil conditions at the project site. Actual compressive strength is verified by testing samples in a laboratory using standardized equipment and procedures.

On commercial projects, numerous samples are tested throughout construction to verify that the concrete being put into place actually has the specified strength. Laboratory testing is not often required in residential work, except perhaps on large, high-end projects or on projects with difficult sites where special foundation designs make concrete strength critical.

For most residential projects, required concrete strength will be in the range of 2,500 to 4,000 psi, depending on the intended use (Figure 2-4). A concrete that is stronger than necessary for its intended use is not economical, and one that is not strong enough can be dangerous.

The primary factors affecting concrete compressive strength are the cement content, the ratio of water to cement, and the adequacy and extent of hydration and curing, all of which are discussed later in this chapter.

Durability might be defined as the ability to maintain satisfactory performance over an extended service life. Satisfactory performance is related to intended use. Concrete that will be walked or driven on must be abrasion resistant so that it doesn’t wear away.

Concrete that will be exposed on the outside of a building must be weather resistant so that it doesn’t deteriorate from repeated freezing and thawing. Concrete in which steel reinforcement is embedded must resist excessive moisture absorption in order to protect the metal from corrosion.

Natural wear and weathering will cause some change in the appearance of concrete over time, but in general, durability also includes the maintenance of aesthetic as well as functional characteristics. Just as concrete mix designs can be adjusted to produce a variety of strengths, appropriate concrete ingredients, mix proportions, and finishes can and should be adjusted on the basis of required durability.


What Are Steel Cables For Structural Works?

Steel cables have been used for many years in bridge construction and are occasionally used in building construction for the support of roofs and floors. The types of cables used for these applications are referred to as bridge strand or bridge rope.

In this use, bridge is a generic term that denotes a specific type of high-quality strand or rope.

A strand is an arrangement of wires laid helically about a center wire to produce a symmetrical section.

A rope is a group of strands laid helically around a core composed of either a strand or another wire rope.

The term cable is often used indiscriminately in referring to wires, strands, or ropes. Strand may be specified under ASTM A586; wire rope, under A603.

During manufacture, the individual wires in bridge strand and rope are generally galvanized to provide resistance to corrosion. Also, the finished cable is prestretched.

In this process, the strand or rope is subjected to a predetermined load of not more than 55% of the breaking strength for a sufficient length of time to remove the ‘‘structural stretch’’ caused primarily by radial and axial adjustment of the wires or strands to the load.

Thus, under normal design loadings, the elongation that occurs is essentially elastic and may be calculated from the elastic-modulus values given in Table 1.8.

Strands and ropes are manufactured from cold-drawn wire and do not have a definite yield point. Therefore, a working load or design load is determined by dividing the specified minimum breaking strength for a specific size by a suitable safety factor.

The breaking strengths for selected sizes of bridge strand and rope are listed in Table 1.8.


What Is The Ideal Water To Cement Ratio?

For brittle ceramic materials, including cementitious systems, the strength has been found to be inversely proportional to the porosity. Often, an exponential equation is used to relate strength to porosity; for example,
fc = fcₒe⁻kt

where fc is the strength, fc0 is the intrinsic strength at zero porosity, p is the porosity, and k is a constant that depends on the particular system.

Equations such as this do not consider the pore-size distribution, the pore shape, and whether the pores are empty or filled with water; thus, they are a gross simplification of the true strength vs. porosity relationship.

Nonetheless, for ordinary concretes for the same degree of cement hydration, the strength does indeed depend primarily on the porosity. Because the porosity, in turn, depends mostly on the original w/c ratio, mix proportioning for normal-strength concretes is based, to a large extent, on the w/c ratio law articulated by D.A. Abrams in 1919: “For given materials, the strength depends only on one factor—the ratio of water to cement.” This can be expressed as: fc = K1/ [K2^(w/c)] where K1 and K2 are constants, and w/c is the water/cement ratio by weight.

In fact, of course, given the variability in raw materials from concrete to concrete, the w/c ratio law is really a family of relationships for different mixtures. As stated by Gilkey (1961a):

For a given cement and acceptable aggregates, the strength that may be developed by a workable, properly placed mixture of cement, aggregate, and water (under the same mixing, curing, and, testing conditions) is influenced by the: (a) ratio of cement to mixing water; (b) ratio of cement to aggregate; (c) grading, surface texture, shape, strength, and stiffness of aggregate particles; and (d) maximum size of aggregate.

Thus, in some cases, simple reliance on the w/c ratio law may lead to serious errors. It should be noted that many modern concretes contain one or more mineral admixtures that are, in themselves, cementitious to a greater or lesser degree; therefore, it is becoming more common to use the term water/ cementitious material ratio to reflect this fact rather than the simpler water/cement ratio.

For ordinary concretes, the w/c ratio law works well for a given set of raw materials, because the aggregate strength is generally much greater than the paste strength; however, the w/c ratio law is more problematic for high-strength concretes, in which the strength-limiting factor may be the aggregate strength or the strength of the interfacial zone between the cement and the aggregate.

Although it is, of course, necessary to use very low w/c ratios to achieve very high strengths, the w/c ratio vs. strength relationship is not as straightforward as it is for normal concretes. Figure 1.8 shows a variety of water/ cementitious material vs. strength relationships obtained by a number of different investigators.

A great deal of scatter can be seen in the results. In addition, the range of strengths for a given w/c ratio increases as the w/c ratio decreases, leading to the conclusion that, for these concretes, the w/c ratio is not by itself a very good predictor of strength; a different w/c ratio “law” must be determined for each different set of materials.


What Are The Construction Industry Ethics?

In 2004, FMI, the nation’s largest management-consulting firm for the construction industry, teamed up with CMAA to survey project owners, architects, engineers, construction managers, and contractors to gauge their concerns about ethics in the industry.

The results, culled from 270 responses, might be kept in mind as we traverse the design and construction industries in the chapters that follow.

The key concerns expressed by the respondents to the survey were fourfold:
1. There appeared to be a breakdown in trust and integrity.
2. There was a perceived loss of reputation for the industry.
3. There was a need to provide a code of ethics and standards.
4. There was a need to create a more equitable bidding process.

Concerns were voiced by owners, architects, engineers, and contractors; they all seem to point to a need for fairness on the part of each party to the construction process.

Concerns about architects and engineers included the following:

Owners stated that architects and engineers do whatever makes the owner happy, often at the expense of the contractor.
Architects and engineers need to express fairness when dealing with contractors or making decisions that affect the owner.
Design professionals knowingly issue plans and specifications that are deficient. Concerns about contractors included the following:
Bid shopping, a practice where contractors use one subcontractor’s price to drive down the price of another to achieve the lowest cost, often an unrealistically low price
Change-order games, played by a general contractor who knowingly submits a low bid in the hope of gaining more profit by issuing questionable change orders as construction proceeds
Payment games, the receipt of payment from one owner, which should be used to pay for labor, materials, and equipment for that project, commingled with funds to pay for other projects
Instituting claims that are vague or specious
Engaging subcontractors whose past performance has been unreliable Concerns about owners included the following:
Owners who authorize work but argue about paying for it
Owners who are very late in their payment of contractor requisitions
Owners who pass off responsibility to others when they are the party that should assume responsibility and resolve problems promptly and equitably
Owners who lack ethical behavior, such as advertising bogus low bids to drive down the price of bidding contractors
Little dialogue between owners and contractors about the expectations of both parties

It appears from this study that there is plenty of blame to go around, indicating the need to maintain and enforce ethical business practices by owner, architect, and contractor alike. So with that in mind, we will now begin the design and construction process.


What Are The Properties Of Fresh Concrete?

Concrete workability is the relative ease with which a fresh mix can be handled, placed, compacted, and finished without segregation or separation of the individual ingredients. Good workability is required to produce concrete that is both economical and high in quality.

Fresh concrete has good workability if it can be formed, compacted, and finished to its final shape and texture with minimal effort and without segregation of the ingredients. Concrete with poor workability does not flow smoothly into forms or properly envelop reinforcing steel and embedded items, and it is difficult to compact and finish.

Depending on the application, though, a mix that has good workability for one type or size of element may be too stiff or harsh for another, so the term is relative. Each mix must be suitable for its intended use, achieving a balance among required fluidity, strength, and economy.

Workability is related to the consistency and cohesiveness of the mix and is affected by cement content, aggregates, water content, and admixtures. Concrete workability is increased by air entrainment.

Entrained air is different from entrapped air. Entrapped air usually accounts for about 1 to 2% of the volume of fresh concrete and its inclusion is not intentional. Small amounts of air are inadvertently entrapped in the concrete mixing process.

Air content can be intentionally increased by a controlled process called air entrainment, which uses either a special cement or a chemical admixture to introduce evenly distributed, microscopic air bubbles. In fresh concrete, the tiny air bubbles act almost like ball bearings or a lubricant in the mix, and in hardened concrete they increase winter durability.

Too much air reduces the strength of concrete, though, so air content is generally recommended to be within the ranges shown in Figure 2-1.

Consistency is the aspect of workability related to the flow characteristics of fresh concrete. It is an indication of the fluidity or wetness of a mix and is measured by the slump test. Fresh concrete is placed in a metal cone.


How To Control  Civil Construction Project Cost?

It is during the design stage that measures to keep the cost of a project within a budget figure are most effective. All possible savings in design need to be sought, not only because this is manifestly in the interests of the employer, but because there are sure to be some unforeseen extra costs that need to be offset by any savings that can be made.

Alternative designs of layout or of parts of the works have often to be studied before the most economic solution is found; hence completion of all design before starting construction makes a major contribution to controlling project cost.

The most prolific causes of extra cost are:

• not completing the design of the works in all essentials before the contract for construction is let;
• not allowing adequate site investigations to take place;
• encountering unforeseen conditions;
• making changes to the works during construction.

The first two listed above can be avoided by taking the appropriate measures. The third, however, is not avoidable even if the site investigations have been as reasonably extensive as an experienced engineer would recommend.

The last – changes during construction – can be minimized by ensuring designs are complete before construction commences, and that the employer takes time to assure himself that the works as designed are what he wants. But some changes are unavoidable if, during construction, the employer finds changed economic conditions, new requirements or more up-to-date plant, or new legislation forces him to make a change.

The designer should keep aware of possible changes to the employer’s needs and other technical developments, and not so design the works that possible additions or alterations are precluded or made unacceptably expensive.

If tenders are received which exceed the budget estimate by so large a sum that the employer cannot accept any tender, means of reducing the cost may have to be sought. Generally speaking, down-sizing a part or the whole of the works is usually not as successful in reducing costs as omitting a part of the works.

Reducing the output of some works or the size of a structure by 25 per cent, for instance, seldom results in more than 10 per cent saving in cost, and can make restoration at a later date to the full output or size an expensive and uneconomic proposition.

If the employer can find some part of the works which can be omitted, this is a more secure way of reducing the cost of a project, and it should be possible to negotiate such an omission with the preferred tenderer.


What Are And How To Install Screw Cast In Displacement Piles?

Whilst the installation of this type of pile is effected by means of a type of auger, the process involves compaction rather than removal of the soil and, in this respect; the piles are of a displacement type. In forming the pile, a heavy-duty single-start auger head with a short flight is screwed into the ground to the required depth.

The auger head is carried on a hollow stem which transmits the considerable torque and compressive forces required, and through which the reinforcement cage is inserted after completion of the installation process. The end of the hollow stem is sealed with a disposable tip.

Following placement of the reinforcement, concrete is placed through this tube from a hopper at its head. As concrete filling takes place, the auger is unscrewed and removed, leaving behind a screw-threaded cast-in-place pile.

By virtue of the combined rotation and controlled lifting applied at the extraction stage the ‘threads’ are of robust dimensions. The sequence of pile construction is shown in Figure 3.6.

This method of forming a pile is known as the Atlas Piling System, and is marketed by Cementation Foundations: Skanska Limited in the United Kingdom, in association with N.V. Franki S.A of Belgium. A purpose-designed, track-mounted rig provides hydraulic power for auger rotation and the application of downward force and is fitted with a crane boom for handling reinforcement and concrete skips.

For a given pile size and volume of concrete, pile capacities are greater than for traditionally constructed bored piles, although the restricted diameter of the reinforcement cage may be a disadvantage if the pile is required to resist high bending stresses. The system does however combine many of the advantages of a displacement pile with the low noise and vibration characteristics of a bored pile.

It will operate in most cohesive and granular strata to a maximum depth of 22 m, providing piles ranging in diameter from 360 to 560 mm. To achieve the torque of perhaps 250 to 350kNm required at the auger, power requirements are relatively high.


What Is A Chicago Boom Derrick?

Chicago Boom Derrick
A Chicago boom can be mounted on a building frame during or after construction, on a tower, or on any frame. Indeed, Figure 1.19 shows one installed on a power plant stack.

When a boom or strut is assembled in the form of a Chicago boom, it can range from as little as 10 ft (3 m) to as much as 125 ft (38 m) in length, and capacities can range from a low of, say, ¼ ton (225 kg) to a practical upper limit of perhaps 35 tons (32 t).

In the not too distant past, booms were made of wooden poles. Short lightweight booms are easily and inexpensively made of single steel pipes fitted with the necessary attachments, but most booms are trussed, or latticed, structures of angle irons or tubing or a combination of the two. Aluminum and synthetic composite booms are plausible, too, where site conditions favors such unconventional materials.

The topping lift usually employs ordinary hoisting blocks; one is fitted at the boom tip held off with steel straps while the opposite end is mounted at the pivot fitting on the support structure also with straps.

The upper load block may consist of sheaves built into the boom head, or it may be a common block suspended on straps.  The purpose of straps is to allow clearance between the rope suspension system and adjoining boom elements through the full range of luffing motion.

A Chicago boom is able to hoist materials to a height above the boom foot, with the horizontal reach limited by the length of the boom and the swing arc by the host structure. Swing guys often are fitted to the boom tip and are run laterally on each side to a point of anchorage.

Wind, friction at the pivots, and the resistance of the opposing guy must be overcome when pulling on the line to swing. With a manual arrangement, the guys are fiber ropes arranged with several parts of line. Hand pulling through several parts can take several minutes to swing the boom through 90°. Where production economics justifies the expense to attain greater speed, mechanical swing systems are used.

In the typical installation, a two-drum winch is used to power the hoisting and topping motions, but when the work involves only lifting and swinging, the topping motion will not be needed. A fixedrope guy line can then be installed, or to make adjustment easier and to provide flexibility.

Visual control can be established when the winch is located at the floor level of the boom foot, particularly when the loads are to be hoisted to this floor, but the winch can be located at any level. When the winch is too large or too heavy to be lifted in the job-site material hoist or in the elevator of an existing building, it may be necessary to use a small temporary winch to operate the derrick in order to hoist the working winch.

Alternatively the winch can be positioned on the ground. When the winch is on the ground, the operator has direct communication with the ground crew and can have the boom and load in view at all times.

When the winch is on the same floor as the boom foot and the loads are to be hoisted to that floor, the operator has direct communication with the swing and load-landing crew and has the boom but not the load in view at all times.


What Is Foundation Engineering?

The title foundation engineer is given to that person who by reason of training and experience is sufficiently versed in scientific principles and engineering judgment (often termed "art") to design a foundation. We might say engineering judgment is the creative part of this design process.

The necessary scientific principles are acquired through formal educational courses in geotechnical (soil mechanics, geology, foundation engineering) and structural (analysis, design in reinforced concrete and steel, etc.) engineering and continued self-study via short courses, professional conferences, journal reading, and the like.

Because of the heterogeneous nature of soil and rock masses, two foundations—even on adjacent construction sites—will seldom be the same except by coincidence. Since every foundation represents at least partly a venture into the unknown, it is of great value to have access to others' solutions obtained from conference presentations, journal papers, and textbook condensations of appropriate literature.

The amalgamation of experience, study of what others have done in somewhat similar situations, and the site-specific geotechnical information to produce an economical, practical, and safe substructure design is application of engineering judgment.

The following steps are the minimum required for designing a foundation:
1. Locate the site and the position of load. A rough estimate of the foundation load(s) is usually provided by the client or made in-house. Depending on the site or load system complexity, a literature survey may be started to see how others have approached similar problems.

2. Physically inspect the site for any geological or other evidence that may indicate a potential design problem that will have to be taken into account when making the design or giving a design recommendation. Supplement this inspection with any previously obtained soil data.

3. Establish the field exploration program and, on the basis of discovery (or what is found in the initial phase), set up the necessary supplemental field testing and any laboratory test program.

4. Determine the necessary soil design parameters based on integration of test data, scientific principles, and engineering judgment. Simple or complex computer analyses may be involved.

For complex problems, compare the recommended data with published literature or engage another geotechnical consultant to give an outside perspective to the results.

5. Design the foundation using the soil parameters from step 4. The foundation should be economical and be able to be built by the available construction personnel.

Take into account practical construction tolerances and local construction practices. Interact closely with all concerned (client, engineers, architect, contractor) so that the substructure system is not excessively overdesigned and risk is kept within acceptable levels. A computer may be used extensively (or not at all) in this step.


A Link On Keyboard Shortcut and Command of Auto CAD

AUTO CAD is a design software made by AutoDesk that is the standard in Civil Construction Drafting and Design.

Design and shape the world around you with the powerful, flexible features in AutoCAD® 2012 software, one of the world’s leading 2D and 3D CAD design tools. Maximize your productivity with updated tools for conceptual design, model documentation, and reality capture.

AutoCAD Keyboard Shortcuts

ALT+F8        VBA Run
ALT+F11      VBA Editor
CTRL+1        Properties Palette
CTRL+2        DesignCenter Palette
CTRL+3        Tool Palette
CTRL+4        Sheet Set Manager Palette
CTRL+5        Info Palette
CTRL+6        DBConnect Manager
CTRL+7        Markup Set Manager Palette
CTRL+A        Selects objects in drawing
CTRL+B        Toggles Snap
CTRL+C        Copies objects to Clipboard
CTRL+SHFT+C    Copies objects to Clipboard with Base Point
CTRL+D        Toggles coordinate display
CTRL+E        Cycles through isometric planes
CTRL+F        Toggles running object snaps
CTRL+G        Toggles Grid
CTRL+H        Toggles PICKSTYLE on/off
CTRL+J        Executes last command
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AutoCAD Line Command: The line command can allow you to create a
single line or a series of lines.
To activate the Line command use one of the following options:
1- Draw Toolbar.
2- Draw from the pull-down menu bar.
3- Key board: Type L for line on the command line and press Enter
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AutoCAD Command Shortcuts
1.  Generally a shortcut prefixed with ” -“  will suppress the associated dialogue from appearing.
2.  Some of the following shortcuts only work with AutoCAD 2006.
3.  Not all of the shortcuts listed work with AutoCAD LT.
ATT ATTDEF Opens attribute definition dialogue box
ATTEDIT ATTEDIT Edit attribute values for a specific block
B BLOCK Opens block dialogue box in order to make a block
BATTMAN BATTMAN Opens block attribute manager
BATTORDER BATTORDER Displays attribute order dialogue box
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How To Make Cyclone Resistant Building?

A cyclone is a storm accompanied by high speed whistling and howling winds. It brings torrential rains. A cyclone storm develops over tropical ocean and blows at speed as high as 200–240 km/hour.

It is usually accompanied by lightning, thunder and continuous downpour of rain. Cyclones extend from 150 km to 1200 km in lateral directions with forced winds spiralling around a central low pressure area.

The central region of light winds and low pressure, known as the ‘eye’ of cyclone has an average diameter of 20 to 30 km. This central eye is surrounded by a ring of very strong winds extending up to 40 to 50 km beyond centre.

This region is called ‘wall cloud’. In this region strongest winds and torrential rains occur. Beyond this region winds spiralling extend outwards to large distances, which goes on reducing with the distance from the centre of the cyclone.

The following care should be taken in designing buildings in cyclone prone areas:

1. Foundations should be deeper

2. R.C.C. framed structures are to be preferred over load bearing structures

3. Sloping roofs should be avoided.

4. Cantilever projections should be avoided.

5. Roof and parapet wall should be properly anchored to the columns and walls.

6. Height of the buildings should be restricted.

7. Suitable wind load should be considered in the building design.

8. Openings in the wall should be less.

9. Structure should not rest on loose soil.


How To Improve The Earthquake Resistance of Small Buildings?

1. Site Selection: 
The building constructions should be avoided on
(a) Near unstable embankments
(b) On sloping ground with columns of different heights
(c) Flood affected areas
(d) On subsoil with marked discontinuity like rock in some portion and soil in some portion.

2. Building Planning: 
Symmetric plans are safer compared to unsymmetric. Hence go for square or rectangular plans rather than L, E, H, T shaped. Rectangular plans should not have length more than twice the width.

3. Foundations:
Width of foundation should not be less than 750 mm for single storey building and not less than 900 mm for storeyed buildings. Depth of foundation should not be less than 1.0 m for soft soil and 0.45 m for rocky ground.

Before foundation is laid remove all loose materials including water from the trench and compact the bottom. After foundation is laid back-fill the foundation properly and compact.

4. Masonry: 
In case of stone masonry:
• Place each stone flat on its broadest face.
• Place length of stones into the thickness of wall to ensure interlocking inside and outside faces of the wall.
• Fill the voids using small chips of the stones with minimum possible mortar.
• Break the stone to make it angular so that it has no rounded face.
• At every 600 to 750 mm distance use through stones.

In case of brick masonry:
• Use properly burnt bricks only.
• Place bricks with its groove mark facing up to ensure better bond with next course.

In case of concrete blocks:
• Place rough faces towards top and bottom to get good bond.
• Blocks should be strong.
• Brush the top and bottom faces before laying.

In general walls of more than 450 mm should be avoided. Length of wall should be restricted to 6 m. Cross walls make the masonry stronger. It is better to build partition walls along main walls interlinking the two.