What is Underpinning? Methods and Procedures for Foundation Repair

A resilient and robust foundation is a sure way to guarantee a stable structure that could withstand and tolerate the forces of nature by satisfying the strength and serviceability requirements. Primarily the significance of foundation in a structure is same as the importance of the word “foundation”. Failure of foundation is a predominant reason behind the instability of the entire structure.

Underpinning can be defined as a technique that is followed to either deepen already built foundation or to repair a faulty and damaged foundation.

The extension of depth in foundation is indispensable if there is a plan to increase the number of floors of a building. Visible cracks observed in the building are a symptom of necessity of foundation correction which can be done by underpinning.

Generally, if the cracks observed in the buildings are greater than one-fourth of an inch then the need for underpinning of the foundation is a must. The problems of heaved foundations, buckled wall, concrete walls with cracks can be regarded as foundation failures.

As per the underpinning method, the damaged foundation is supported with the help of permanent or temporary support. This arrangement will help in increasing the bearing capacity as well as additional extension of the depth.

Structural Requirements That Make Underpinning a MUST

There are certain failure conditions of foundation that will make the engineer to come up with the decision of underpinning.

The answer to the question that When to use the underpinning method for foundation repair? is answered below:

1. Most of the normal buildings have foundations that are made from timber. These after a time period will undergo settlement. These settlement of the foundation is due to the degradation of the timber which is caused by the water table fluctuations.
2. The bearing capacity of the soil is decreased with the rising and the lowering of
3. the water table. This will result in the settlement of the structure.
4. Construction of structure over a soil with lesser bearing capacity too result in the settlement of the structure.

Repair of Foundation by Underpinning

The distress observed in the foundation may be due to settlement as mentioned or due to the movement of the slope or due to the expansive soils present underneath. The main requirement of foundation repair is,

• Either to stabilize the foundation in the present condition so that no further distress is welcomed.
• Or to lift and restore the foundation to a particular elevation as required

Diagnosis for foundation repair by Underpinning 

There are certain steps to be determined initially to understand the risk of the foundation. These include:

1.   Surface Exploration so that cause of distress is determined
2.   The foundation risk and the potential repair is enlisted
3.   The  above  risk  is  discussed  with  the  owner  and  develop  a  decision  for underpinning.
4.   The need for partial or fully underpinning is made

Methods of Underpinning Foundation

There are different methods which can be followed to undergo underpinning procedures which are explained in detailed below.

1. Mass Concrete Method or Pit Method
2. Pier and Beam Underpinning Method
3. Underpinning by Cantilever Method
4. Pile Method of Underpinning
5. Pre-test Method of Underpinning
6. Mini Piled Underpinning

Even if there are different method of underpinning for the repair of foundation, all the methods follow same concept of extending the foundation.

The extension made can be either in lengthwise or breadth-wise. This is done over a soil which is strong, hence equal distribution of the load is taken place.

Mass Concrete Method of Underpinning

This method is also called as pit method and is a traditional method of underpinning. The method will carry out the procedure of extension of the foundation till it reaches a hard stratum. For this, the soil below the existing foundation is removed and excavated. The removal is carried out in stages so that sudden collapse of soil is not occurred. Once the stratum is approached it is filled with concrete and allowed for curing afterwards. Only after completion of one stage, next excavation is started.

Fig-1 Pit Method of Underpinning

The existing foundation has to transfer safely load to the new foundation i.e the mass concrete footing as shown in figure-1 above. For this, a pin is provided in between them by placing a pack of dry sand-cement.

This method of underpinning is performed for a shallow depth. The method have an advantage that no kind of machinery is necessary for the excavation process. The new

mass concrete structure constructed will behave as a barrier and protect the old foundation.

Cantilever Needle Beam Method of Underpinning

This method is an extension of above-described pit method and is often named as Cantilever pit method of underpinning. This method is suitable if the building has a strong interior column and that the deepening of foundation can be done only in one direction due to site limitations.



In this method an underpinning pit is excavated beneath the existing exterior wall whose foundation is faulty. A needle beam is strapped to join the exterior wall with that of existing interior loaded column or pedestal. The exterior wall is hanged with the needle beam arrangement pushed up by a hydraulic jack supported on Fulcrum.

Fig-2 Extended Pit Method of Underpinning 

This method is faster than the traditional method. With this procedure being adopted the load carrying capacity of foundation is increased.

Another slight modification of this method also exists in which the existing foundation is supported by a Cantilever beam strapped to tension piles and compression piles which were rested on firm strata underneath as shown in the figure below.

Fig-3 Cantilever Needle Beam Method of Underpinning-Sectional View

Pier and Beam Method of Underpinning

This method is developed to cover the limitation of mass concreting method. This method is good for relatively deeper foundation and is feasible for all the soil conditions. In this method reinforced concrete beams are placed supported on the mass concrete underneath the ground or piers as shown in figure-3.

Fig-4 Pier and Beam Method

The ground conditions and the extent of load to be carried will decide the size and the dimensions of the piles. For foundation that is deeper than 6m, this method is economical.

Mini Piled Method of Underpinning

For cases where the load is to be transferred to a stratum that is situated at a depth greater than 5m can make use of mini piles of diameter 150 to 300m. Areas, where the soil nature is highly variable and is a restricted area for access, can make use of this method. These piles can be either driven steel or augured types. The maximum depth possible is 15m.

Here as shown in the figure-4 piles are driven on either sides of a weak foundation. The piles driven are connected to the existing weak foundation through needles. These needles hence act like a pile cap.

Fig-5 - Pile Method of Underpinning

The settlement issues that are caused due to water clogging or the clay nature of the soil can be corrected by this method.

As shown in the figure-4 a hole is made in the existing wall to facilitate the needle beam.

Pre-test Method of Underpinning

This method is suitable for buildings with 5 to 10 stories and the foundation type of pad and strip footing.  The method will involve the initial compaction as well as compression of the underneath soil after excavation. Thus, soil is subjected to predetermined loads.  All these procedures are done before underpinning.  Raft foundation can also use this method. The pre-test method has less noise and disruption during construction.

Whats Next? 

If your house is having a foundation that is still not solved by underpinning than you must opt for Pile foundation and We have written a detailed article about it so why not go to that.

Pile Foundation, Types and Procedures

What is Stamped Concrete? – Its Features and Its Construction

The Stamped concrete can be defined as a finish that is provided to the concrete in its wet state. Specific designs or patterns are stamped on the concrete in its plastic state as shown in the figure-1 below.

Fig.1. Stamped Concrete Preparation on a Concrete Driveway

The stamped concrete provides a great option in terms of realistic colors, textures, and patterns. These will hence end up with a final product finish similar to that obtained from the installation of granite, marble or costlier sandstones or tiles. Thus, stamped concrete provides great option for the designers to choose a design for the floor for various budget and aesthetics.

A greater advancement in the area of stamped concrete have resulted in the development of new patterns similar to the stone patterns. 

Fig.2. Stamped Concrete Finish similar to Stone Patterns

The use of stamped concrete will help in achieving the appearance of an imported stone for a lower cost.

Stamped Concrete Construction 

A teresting texture is provided by the application of stamped finish for the sidewalks, patios, and driveways. The main design element for the process is stamping mats. The figure-3 below shows some of the rubber - stamping mats that are available. There are numerous designs of stamping mats in the market.

Fig.3: Stamping Rubber Mats with Hexagonal, brick and square patterns

Along with the decision of implementing stamped concrete, it is very necessary to bring a decision on the layout of stamping and the type of stamping pattern that will suit your floor. This will help in maintaining a consistent pattern throughout the course of the project. 

To maintain a consistent layout, a reference line is made during the stamping of the initial stamping mat. Further stamping can be carried out with respect to the initial reference line hence achieving proper alignment and consistency. Each stamping mat will be aligned with the before stamped layout. This method is followed till the end of the project. 

The textures at the corners of the stamped portion mostly have to be finished by hand. Necessary obstructions can be created on the surface with the help of special stamps or by using an aluminum chisel. 

The stamping pads is pressed with pressure over a concrete surface that is in its plastic state (slightly stiff) to a depth of 1 inch. 

Stamping a Concrete Surface

The process of stamping a concrete surface can be conducted by the following step by step procedure.

Step 1: To a prepared formwork, the concrete of required mix ratio is poured and leveled to form a concrete slab. A reference line is made at the point where the first mat is intended to be placed or at the center of the form. The time we observe that the bleeding water has disappeared from the surface of the slab, a release agent in the form of powder is tossed on its surface. The amount to be tossed is dependent on the instructions given by the manufacturer. The procedure is shown in the figure-4.

Fig.4: Preparation of Concrete Surface for Stamping

Step 2: Next is the process of aligning the stamping mat of desired pattern over the prepared concrete surface as shown in the figure-5.

Fig.5: The first Stamping of the concrete Surface

The stamping mat is aligned with respect to the reference line made and based on the layout plan. It is to be noted that once the mat is placed, no kind of adjustment have to be conducted. The mat can be pressured and embedded into the concrete either by stepping over it or by tamping with hand.

Step 3: Now the second stamp is taken and placed against the first as shown in figure-6. And if there are many stamps of the same pattern, it can be embedded in the continuous pattern. If only one mat is available, after each stamping, the mat have to be removed and continue the stamping.

Fig.6: Placement of Second pad for stamping the concrete

If we have to reuse the mat after each stamping, then it is suggested to complete row-wise first before finishing lengthwise.

Step 4: Once the stamping procedure is over, the surface is cured for 3 days. The releasing agent that is used can be removed with the help of pressure washer. Then a complete curing can be performed for the concrete surface for a time period of 1 week. Finally, as per the manufactures, an acrylic concrete sealer can be provided. After which the formworks and the backfills can be removed, as shown in figure-7.

Fig.7: Finishing the Stamped Concrete with a Concrete Sealer

Based on the aesthetic views of the worker or as desired, more and more detailing works can be performed on the stamped concrete with a roller to defined each block, or texture skin that will provide the look of a natural tile or a stone. Most of the professional stamping pads with give complete finish for the concrete surface. 

Tips while Stamping Concrete

Some essential tips can be followed before you work with a new stamping pad or if you are new in stamping concrete.

• Before working on concrete, we can apply the pads on a bed of compacted sand.
• Always try to bring random designs. Avoid placing the stamping pads in a repetitive pattern. 
• Better results will be obtained if we use a releasing agent. This will help to avoid any kind of breakage of concrete while taking out the stamping pads.
• Check the alignment of the stamping pad periodically.
• The person who is working over the concrete surface, performing the stamping procedure must wear a boot or work shoes that is clean. It must be free from debris, pebbles or other dirt. Or else these contaminants will also be impressed over the concrete surface. 

What is Frost Wall? Purpose & Types

Building houses and structures in extreme climates is always a challenge, the temperature depending characteristics of building materials is the sole reason for such a trial. Concrete pouring in hot expands too much and in cold climate contracts too much thereby producing such internal stresses that if not properly taken under-consideration would produce extreme internal strains that might be havoc for the structural integrity and serviceability of the structure. 

What is Frost Wall? Purpose & Types

In this post today we will talk about the condition of the soil in freezing weathers and its adverse effect in the form of frost heave and its solution in the form of frost wall. 

Reason why Frost Wall is needed? 

From soil mechanics, it is a well known fact that the matrix of soil particles has voids and gaps that are partially filled by air and water for non-saturated soils. For dry soil (oven dry) the voids are only filled with air while for saturated soils the voids are completely filled by water. Mostly the soil underneath the foundation of the building is soil with partially filled voids by water. This water, during extreme cold climates when the outside temperature falls, freezes and thus producing frost heave. 

Frost heave expands as the ice in the soil accumulates in a structure called ice lens and as we know by the behavior of water; the volume of water increases as it is converted to ice. Thereby, due to conversion and growth of water to ice lens in the soil voids, they push the nearby surrounding soil. The structures having foundation resting on such soils will be shoved upward and thus damaged by the action of ice. The stress reversal occurs after suitable increase in climate and thus thawing might occur relieving the upward shoving of the structure.  

The only remedy for this problem exists in preventing the freezing and heaving of the underneath soil of the foundation. The reason we don’t want the ground to freeze is that frozen ground moves and thus moving the concrete walls up and down. 

What is Frost Wall? 

Frost walls are actually insulating walls that are constructed / placed deep in the ground around the periphery of the foundations beneath the frost line; so that in the cold winters when the ground freezes the walls and the footings are sitting on will not end up with the ground freezing underneath them. 

Sometimes the term frost wall is also referred to the walls placed above ground inside the house for insulation. And sometimes it is also referred to an insulating layer / frost protection of soil placed between house foundation and a wall constructed sufficiently gapped. This type of frost wall only worked for heated structures. This type of frost wall holds heat from the structure in the ground to prevent freezing in areas where ground frost is common.

The frost wall may be load bearing or non-load bearing; in case of load bearing wall the frost wall itself is a foundation wall that takes the foundation deep enough which is below the frost line of that area. In case of non-load-bearing wall it is just an insulating barrio as explained above. The basements in many older homes are not insulated and, therefore, require a frost wall built just inside the basement’s exterior walls to reduce heat loss through the foundation. The interior wall should not touch the exterior wall, and should include a moisture barrier to prevent moist interior air from forming ice inside the wall.

Before the frost wall is fully functional, in case of a basement beneath the building, some preparatory works needs to be done for an effective heat-loss-control phenomenon. For example, basement walls that are made from cinder blocks require the homeowner to patch any open gaps in the mortar with brick filler. Basement walls that are made from poured concrete require the homeowner to patch any cracks with concrete sealer. Once the concrete sealer is applied, the next step is to apply a paint sealer, specialty paint that helps prevent moisture from entering the basement. This is extremely important because the formation of moisture between the frost wall and the basement wall promotes mold growth.

Types of Frost Walls 

Protecting Shallow Foundation with Frost-Protection Insulating 

This type of frost wall is non-load-bearing wall and is meant to protect a building with shallow foundation when deep foundation is not-economical or not-feasible. The wall constructed after leaving a sufficient gap with the building foundation would prevent the soil from losing heat. In such a type of frost wall, the soil surround a building’s foundation would warm up by the heat that is radiated from the building.

Protecting Shallow Foundation with Frost-Protection Insulating 

A layer of rigid foam insulation is applied vertically to the outside of the foundation wall, and another layer of rigid insulation is placed horizontally under the soil at the base of the foundation wall. These layers of insulation direct the warmth from the heated interior of the building downward into the soil and keep it there so that the soil does not freeze.

Frost-protection wall for non-heated Buildings

Frost wall of type 1 explained above is only applied for a heated building as in such a frost-protected wall the warmth radiated by building is the only source of heat. But for unheated buildings such a type of frost wall will not work.

Frost-protection wall for non-heated Buildings

An alternative design would be to use the heat of the temperature of deeper layers of earth which is always around 40 to 50 degrees throughout the year. In this design, a horizontal layer of insulation is laid under the building's entire foundation and extends outward from the foundation, but there is no vertical insulation. 

The layer of insulation rests on a layer of gravel. The warmth of the soil is stored and radiated upward, preventing the upper layers of soil from freezing.

Cost

Although for the cost, it depends on the design, but usually it is not an expensive structure and keeping the long-term benefits in view the economy is not the decisive factor whether to build it or not. Usually they are a 4 ft high concrete wall sitting on a footing. Usually they do not require water proofing or structural steel, this is because they are back-filled on each side in your walkout basement. 

What is Efflorescence? Causes, Prevention and Removal Techniques

The brick masonry industry is plagued with a stubborn and persistent confusing delinquent trouble frequently seen as white powdery scum on a lot of buildings. This white powdery substance is termed as efflorescence which is, although, not well understood but still the masonry industry is still able to define it, knows where it comes from and also methods to reduce and prevent this badly-behaved nature in brick masonry have been device and practiced these days.  

Sure Ways to Prevent and Cure Efflorescence

According to dictionaries the efflorescence is defined as:- 

A change on the surface to a powdery substance upon exposure to air, as a crystalline substance through loss of water.

To become encrusted or covered with crystals of salt or the like through evaporation or chemical change.

Actually efflorescence is a deposit of water-soluble salts that are left on the surface of masonry as a crystalline powder sometimes white or brown or green or yellow after the water evaporates from the exterior surfaces upon exposure. You might have not seen any color other than white but still it exists depending on the type of salts etc. 

This is a prominent defect in brick masonry. In moist climate, in damp places, like basements or under leaky gutter, masonry often gets disfigured. Deposit originates from the mortar and frequently spreads over a part or entire face of the wall. 

Absorbed water dissolves the salts of sodium, potassium and evaporating, forms a crystalline deposit on the surface. In addition to unsightly appearance, the crystallization of salts in the pores of the bricks or mortar may cause disruptive expansion resulting in disintegration due to cracking. 

The problem of efflorescence is not new; its existence finds its way back in the prehistoric primitive times as the brick masonry was ever started and great piece of time, money and efforts have been made and spent trying to solve the difficulties generated by this persevering problem.  

The timing of when the efflorescence appears is very critical, it open appears just after the completion of the structure and is thus named as “new building bloom”.  And at this time the contractor, builder or architect are mostly concerned with the appearance of the new structure. The appearance of efflorescence is triggered by variation of temperature and is obvious during the winter, but may also be observed throughout the year following heavy rains and sudden drops in temperature.  In summer, even after prolonged periods of rain, moisture evaporates so quickly that only small amounts of salt are transported to the surface. However, during winter, slower rates of evaporation lead to migration of salts to the surface. 

This article will explain in detail about the sources of the efflorescence, how it works, about the attempts that are to be made in order to reduce its destructive effects and if it does appear the ways to remove it.

Sources and Causes of Efflorescence  

In most general cases, the efflorescence is caused when the water gets mixed with masonry material and thus moving the salts to the surface and usually the free salts were created. In other cases when the free salts are readily available the free water dilutes it into a solution which is transported through brick masonry depositing it on the surface referred as efflorescence. 

During detailed analysis of the efflorescence it was found that sometimes the salts which are deposited inside the brick masonry form a crystal depositing within the matrix of masonry called crytoflorescenc as it is not visible. 

Conditions for Efflorescence 

The subject of efflorescence is not that simple, it is a confusing mechanism and the real cause is hard to find sometimes. However, it is well known that there are three conditions that must be met in order for the efflorescence to appear. 

• First: There must be water-soluble salts present somewhere in the wall
• Second: There must be sufficient moisture in the wall to render the salts into a solution
• Third: there must be a path for the soluble salts to migrate through to the surface where the moisture can evaporate, thus depositing the salts which can crystallize and cause efflorescence. 

These three conditions must be simultaneously existed in any structure for the appearance of the efflorescence which means if any one of the cases does not exists than no efflorescence will appear. 

Although the efflorescence is a complex problem, the prevention is not that difficult with economic and feasible steps there exists ways to reduce any one of the cases/conditions required and is thus making nearly impossible for efflorescence to occur. 

Sources of Salts 

The chemical reason and nature of efflorescence is very complex as there are many chemicals in the clay bricks, concrete blocks, mortar used, cement, lime, sand, admixture and ground water that can cause sulfates, carbonates, sodium bicarbonate or silicate to cause efflorescence. The efflorescence in green color which is often termed as “Green Stain” is a result of certain vanadium and molybdenum compounds present in some ceramic brick units. Similarly in brown color the efflorescence called “Brown stain” exists which is due to manganese deposits. 

 The appearance of efflorescence is generally not dependent on the quantity present of the water soluble salts as it is reported that even very small quantities of water soluble salts causes efflorescence.  Sodium and potassium hydroxides are commonly present in Portland cements which may cause some efflorescence during the first year after construction. This is known as “Building-bloom”, a condition which typically disappears after a short while. 

Moisture 

If your house/building you are constructing is in areas of high annual rainfall than it must be considered in the initial stages and planning of project that the materials will be subjected to higher quantities of water both during and after construction making it more susceptible and liable for efflorescence. Similarly even if the rainfall is not more, the area is near sea where humidity is always more than in such areas the projects are also greater exposed for efflorescence potential. 

As water is always needed for the salt to dissolve, which means if more water exists the more solution will be prepared and thus more salt will dissolve causing more efflorescence. 

So after discussing sources and reasons of efflorescence we can conclude that detailed study of the following items is necessary for judging the reason and prevention measures for the efflorescence :- 

1. Moisture 

2. Construction Material

3. Temperature

Preventive and Controlling measures 

Since many factors influence the formation of efflorescence, it is difficult to predict if and when any will appear: There is no accepted standard test method for   reassuring the efflorescence potential of masonry mortar. Several experimental methods have been proposed, but none has been accepted as effectively predicting the performance of mortar materials in actual use.

After finding the reasons and causes of the efflorescence it will be easy for the one to control it prior to avoid the situation to get worsen. Even if the soluble alkali sulfates exist in a masonry wall, before the sulfates can cause efflorescence the salts must be dissolved into solution by water. If no moisture reaches the sulfates than they cannot be rendered into solution and migrate to the surface where the water will evaporate, leaving the sulfates salts on the surface to crystallize and become efflorescence. Attention must be given to preventing any soluble alkaline sulfates from being rendered into solution by water. 

This is difficult since during construction water is naturally used in the mortar and grout; therefore the amount of water in the wall should be controlled to only reduce the amount necessary for actual construction. The majority of the water is absorbed into the masonry and used to chemically react with the Portland cement and hydrated   me and is thus not free water.

To avoid Efflorescence do not use porous bricks in contact with limestone. Protect brickwork against contamination of salt-bearing materials during building operations. Bricks should be thoroughly soaked during construction. Correct design of DPC should be used.

Once the cause of efflorescence is corrected, the removal of the deposit is relatively easy, since most efflorescing salts are water soluble. In general, efflorescence can be removed by dry-brushing followed by flushing with clean water. If this is not satisfactory, walls can be washed with a five to ten percent solution of muriatic acid. It is always advisable that a small inconspicuous test area be tried first to determine whether etching or other discoloring will occur. After the acid treatment, the surface should be immediately and thoroughly flushed with clean water.

To summarize, three conditions must exist before efflorescence can occur. If these three conditions can be controlled, there should be no efflorescing of masonry walls.

1. Reduce all soluble alkali sulfates.

2. Use good details to prevent water from entering the masonry.

3. Use good construction practices to eliminate migratory paths for moisture.

Remember, it is very difficult to totally control any one of these three conditions, but it is relatively simple to reduce the effect each one has towards efflorescence. The following 5 simple ways are a sure way towards efflorescence free brick / block masonry for your project. 

1. Limit Driving Moisture Force

2. Provide for good drainage

3. Construct good mortar joints

4. Ensure proper curing

5. Limit Water Entry

Civil Engineering Jobs in Infrastructure Development Authority IDAP, Punjab, October, Novmeber, 2017

The infrastructure Development Authority (IDAP) has been established by the Government of the Punjab for planning, designing, construction and maintenance of Infrastructure in Punjab in line with best international practices. They are offering highly competitive compensation packages, attractive incentives and an opportunity to become part of a world leading initiative.

Civil Engineering Jobs in Infrastructure Development Authority IDAP, Punjab, October, Novmeber, 2017

1. Senior Manager Planning & Design
2. Manger Planning (Forensic)
3. Manager Planning
4. Assistant Manager Planning
5. Manager Quality Control
6. Manager, Cost Control
7. Manager Document Control
8. Assistant Manager Cost Control
9. Assistant Manager Estimation
10. Manager Contracts Administration
11. Project Coordinator
12. Assistant Manager Reporting
13. Manager Projects
14. Assistant Manager Projects
15. Assistant Engineer
16. Quantity Surveyor
17. AutoCAD Designer

Application form can be downloaded from website www.idap.pk/carreers.php. 

Last date to apply: 27-Oct-2017

You can apply online or send through courier

Infrastructure Development Authority Punjab, Government of Punjab, GM HR Ground floor, 7-C-1, Gulberg III, Lahore, Pakistan. 

Project Coordinator Civil Engineer Jobs in Punjab Daanish Schools and Centers of Excellence Authority

The Punjab Daanish Schools and Centers of Excellence Authority (PDS&CEA) is an autonomous organization established under the auspices of  Government of the Punjab, PDS&CEA seek services of highly dynamic and committed professionals on contract basis of the following posts: -

Project Coordinator Civil Engineer Jobs in Punjab Daanish Schools and Centers of Excellence Authority

Name of Post: Project Coordinator

Qualification: BSc Civil Engineering or M.Sc. Project management from HEC Recognized University

Experience : 05 years experience of Project coordination and management

Age limit: upto 55 years

Pay Scale OG-1 (Equivalent to BPS-17) Gross Salary upto Rs.80,000 /- per month all inclusive.
Applicants shall attach with their applications a detailed resume, certificate copies of qualifications, experience certificates, CNIC and 2x passport size photographs.

Applications to be send by post.

Last date to apply: 03 Nov – 2017

Manager (Admin / HR & Coord)
Punjab Daanish Schools and Centers of Excellence Authority, Govt. of the Punjab, Japanese Cell Building, Research Station, near Punjab University, Canal Bank, Lahore,
042-99230633, 99231737-40

Civil Engineering Internship Opportunity in Overseas Pakistanis Foundation (OPF) Internship Program

Overseas Pakistanis Foundation (OPF) Internship Program for Overseas Pakistanis Under Corporate Social Responsibility

Civil Engineering Internship Opportunity in Overseas Pakistanis Foundation (OPF) Internship Program

Applications are invited from Fresh Graduates/Post Graduates for 01 year internship program, designed for practical training to the educated youth belonging to overseas Pakistanis families for enhancing their skills: -

Displine: Civil Engineering
No. of Seats: 30
The interns will be paid a monthly stipend depending upon the qualification on the basis of which they are applying.
Eligibility: CGPA 3.00 (in final degree)

Max. Age Limit: 30 years.

Applications are to be sent online at www.opf.org.pk/careers/internships/

Last date to apply online is 13-Nov-2017

For further information
Call 051-9048209
051-9048222

Demolition Process and Methods for Buildings and Structures

Demolition is the deliberate destruction of structures and materials by means of explosives, mechanical devices, fire, chemical agent, etc.

What is Demolition?

Demolition is a pre-planned and controlled bringing down or destroying of a building or structure while considering all the safety precautions.

According to Wikipedia demolition can be defined as “dismantling,razing, destroying or wracking any building or structure or any part thereof by pre-planned and controlled manner.”

Demolition Process and Methods for Buildings and Structures

Demolition of a building or structure may involve complete or partial dismantling excluding any refurbishment or alteration of existing structural components.

Another sister term of demolition is implosion; implosion is the name given to the method of demolition by means of explosives.

Huges & Salvidge is a renowned British Company specializes in number of methods for the demolition of commercial, industrial buildings including high-rise blocks or flats.  

Before carrying out the demolition at site, cautious and careful planning is a definitive pre-requisite. A pre-start meeting must takes place guiding all the works and management personals about their duties and Risk Assessments is done. A Method Statement, containing the methods of demolition techniques to be used, is then produced to control the highlighted risks.

Why demolition is needed?

The life cycle of concrete structures is usually 40 to 90 years. During this life, structures often meet with some situations like disasters, changing functions, city reconstruction, or higher residence demand due to population, all these lead to demolition or reconstruction of existing structures. The structures which have already passed their design life need to be reconstructed for safety and operational requirements.

In developed countries demolition is very essential for development of new structures for various residential and industrial purposes. Small structures can be demolished by manual methods but machinery and advanced techniques are required for demolition of bigger structures. Advanced techniques are also required for faster demolition and demolition in confined areas.  The government agencies are also needed to demolish the buildings which violate the building rules and regulation ensuring structural safety, health, fire safety and construction safety of the building.

Any kind of demolition work needs labor forces for executing the work. Today various kinds of demolition methods are available, but the method of implementation for demolition work varies with the site condition, safety and cost.

Demolition Sequence

Before the start of Demolition Project the demolition sequence is properly determined keeping in view the actual site conditions and restraints to avoid any confusion and loss later in the project.

The structure to be demolished is properly surveyed and the surroundings are properly inspected for any utilities. If there are any utility lines present like electricity, plumbing water lines, drainage connections; than these must be properly plugged or discontinued. Organize testing and checking for presence of any hazardous material e.g. Asbestors – if any, removal of Hazardous material by specialist contractor must be ensured.

If the building have any cantilever structure like verandah or canopy that must be demolished first. The presence of lift machines and watertanks at high level must be demolished in top down sequence to the main roof level.

In case of demolition for the roof slab; it must be ensured to initiate demolition from the center mid span and then work outwards towards the supporting beams of frame structure. In case of roof slab supporting on walls, the non-load bearing walls must be demolished before demolition of load bearing walls. Columns and load bearing walls shall be demolished after removal of beams on top. If site conditions permit, the first floor slab directly above the ground floor may be demolished by machine standing on ground.

Demolition Methods & Techniques

If you are looking for a career in Demolition Industry than you must get ready to face defies and challenges due to uniqueness and exceptionality of each project in terms of the surrounding environment to the structure and the materials used.

The selection for the Demolition Method or Process is dependent on some factors like:-

a.       Area where the building is located

b.      The time available for demolition

c.       The building material

d.      The purpose of the demolition

e.      The way waste debris is going to be disposed

f.        Noise and Dust Control factors (HSE)

In the past when the technological innovations have not found its footprints in the construction industry, the buildings and structures were dismantled by humans manually through hammers at the end of their lives due to structural of functional obsolesces. But mankind has learned from their mistakes, failures and disasters due to lack of awareness and knowledge on demolition.

The demolition method also varies with the time available for demolition and need of site clearance for the new structure. Before execution of demolition work, the careful study of site condition, the type of structure, structural member, demolition range, rural or urban area and frequency.

The application of method for demolition depends upon actual site condition and available space.

We can classify the demolition methods or demolition techniques into two broad categories one can be called conventional method and the other can be called non-conventional methods. According to a research from University of Salford, demolition techniques are now not only numerous but also varied in their technology, application, cost and speed.  

Manual Methods

In conventional and manual methods the demolition work is carried out manually by hands or hammers. Sledge hammer, chisel or jack hammer and drilling equipment is used. This is a very slow and rather cheap method of demolition which can be used for small house or residential building.

Demolition by Wrecking Balls

This is one of the oldest and commonly used methods of building demolition. A crane uses a wrecking ball, weight upto 6120 kg, which is either dropped onto or swing into the element to be demolished. The ball is made from forged steel, which means the steel is not cast into ta mould in a molten state. It is formed under high pressure while the steel is red hot (soft but not molten) to compress and to strengthen it.  Concrete members can be broken into small pieces, but secondary cutting of reinforcing may be necessary.

Single in-line method or vertical drop method are used in case of crane and ball method.

Demolition of a Building Structure

Advantages:

To demolish roofs and other horizontal spans

The wrecking balls are still used when demolition may not be possible due to local environmental issues or asbestos/lead building content.

Disadvantages:

It demands a great deal of skill from the crane operator.

The height of a building that can be demolished is limited by crane size and working room; however, buildings as high as 20 stories have been demolished.

The breakup process can cause considerable dust, vibration and noise which may be objectionable.

Demolition.

Selective or complete demolition of concrete structures is possible by cutting elements and then removing by crane. The cutting process may be sawing, water jetting or thermal lance. Because the surface of the cut concrete is smooth and relatively regular, these methods have particular application when the objective is partial demolition, for instance in the creation of openings in walls and slabs.

Hydro Demolition

Cutting with a water just minimizes dust and eliminates vibration and fire hazards. An abrasive and water-catching system is required to clean up during the jetting process. Hydro demolition uses a high pressure supersonic water jet, that penetrates the pores and cracks of the concrete and builds up an internal pressure. When this pressure exceeds the tensile strength of the concrete, the concrete breaks. The water jet can be used not only for cutting straight lines but also contours a useful features for cutting access manholes.

Hydro Demolition

Thermal Lance

A thermal lance is created by packing a seamless mild steel tube with low carbon rods and passing oxygen through the tube. While this method eliminates vibration and dust problems, it creates other hazards associated with smoke and fire danger. Whether sawing, jetting or lancing is used to dismantle the structure or its components, each element must be safety lowered to the ground.

Pneumatic and Hydraulic Breaker

A common piece of equipment used for demolishing bridge decks, foundations and pavements is a hydraulically or pneumatically operated, boom-mounted breaker. The advantages of a machine mounted breaker may include a telescoping boom for easy reach and remote control operation and underwater demolition capabilities. Some of the smaller remote-controlled machines can be lifted through window openings and used inside a building to demolish floors and walls. Productivity can vary greatly depending on the size of hammer, type of concrete, amount of reinforcing and working conditions.

A jackhammer is a pneumatic or electro-mechanical tool that combines a hammer directly with a chisel. Hand-held jackhammers are typically powered by compressed air, but some use electric motors. Electric powered tools come in a variety of sizes from about 12 lbs to 65 lbs. They required an external power source, but do not require a compressor.

A hydraulic jack hammer typically much larger than portable ones, may be fitted to a mechanical excavators or backhoes and is widely used for roadworks, quarrying and general demolition or construction groundwork. They are used in mines where there is an explosion risk since they lack any high-power electrical circuitry that might cause a trigging spark. The jackhammer is connected with hydraulic hoses to a portable hydraulic power pack; either a petrol or diesel engine driving a hydraulic pump.

Explosives

In the controlled demolition industry, building implosion is the strategic placing of explosive material and timing of its detonation so that a structure collapses on itself in a manner of seconds, minimizing the physical damage to its immediate surroundings. Despite its terminology, building implosion also includes the controlled demolition of other structure, such as bridges, smokestacks, towers, and tunnels. Numerous small explosives strategically placed within the structure are used to catalyze the collapse. Nitro-glycerin, dynamite, or other explosives are used to shatter reinforced concrete supports.

Blasting methods employ rapidly expanding gases confined within a series of boreholes to produce controlled fractures which provide for easy concrete removal. For the demolition of concrete structures it is usual to drill holes at a predetermined angle into the concrete to be removed. Implosion is the strategic placing of explosive material and timing of its detonation so that a structure collapses on itself in a matter of seconds, minimizing the physical damage to its immediate surroundings. The technique weakens or removes critical supports so that the building can no longer withstand the force of gravity and falls under its own weight.

Safety Precautions during Demolition

Hoarding

Hoarding and Protective Screens isolates the demolition site from the public, thus preventing unauthorized access and trespassing.

Safety Precautions during Demolition

Walkways

Walkways shall be provided for the use of the workmen who shall be instructed to use them an all such walkways shall be kept adequately lighted, free from debris and other materials.

Catch Platforms

In demolition of exterior wall of multistoried structure, catch platform of heavy planking shall be provided to prevent injuries to the worker working below and to the public when the external walls are more than 20 m in height.

Whats Next…to Demolition????

A new approach to demolition is the deconstruction of a building with the goal of minimizing the amount of materials going to landfills. This "green" approach is applied by removing the materials by type material and segregating them for reuse or recycling.

With proper planning this approach has resulted in landfill diversion rates that exceed 90% of an entire building and its contents in some cases. It also vastly reduces the CO2 emissions of the removing of a building in comparison to demolition.

I hope you loved the article about Demolition Techniques and Demolition Methods if you have any further questions and additions please do comment on the form below. 

General Manager Civil Engineering Jobs in Lahore Knowledge Park Company, Lahore, Pakistan

Civil Engineering Jobs in The Lahore Knowledge Park Company (LKPC) is a public sector large scale organization registered with the SECP under Section 42 (not-for-profit) of the Companies ACT 2017 through the Higher Education Departement (HED). Government of the Punjab with the vision and aim to develop Lahore Knowledge Park by Establishing Campuses of internationally well-reputed universities / institutions to drive growth and knowledge ecosystem. 

Application are invited from the candidates for appointment on 

Name of Post : General Manager (Engineering) 

Education / Experience : 

A minimum of B.Sc. (Degree) in Civil engineering from a reputable HEC Recognized University local / foreign. 

Fifteen (15) years of experience in construction and infrastructure development programs and execution of large scale projects in private / public sector. 

Must be well versed in construction planning infrastructure planning, urban planning and zoning; construction/building designs, site supervision and inspections, quality assurance, BOQs and code compliances. 

Certification in Project management like PMP will be a plus. 

Age Limit : 55 Years 

No. of Posts: 1 years

Candidates can apply on a simple paper, CVs along with 2 photographs, national id card and testimonials applications completed in all respect should reach by post latest by 27th October, 2017. 

Detailed job description for each post can be downloaded online from LKPC website. 

General Manager Human ResourceLahore Knowledge Park Company 15-Abubakar Block, New Garden Town, Lahore, UAN: 92-42-99075000

This Civil Engineering Jobs in  Lahore Knowledge Park Company, Lahore, Pakistan is best opportunity for experienced Civil Engineers. All Civil Engineering jobs in Lahore Knowledge Park Company, Lahore, Pakistan is collected from different Newspapers on every Sunday and shared for our viewers so that that can apply for the job and get the employment in Lahore Knowledge Park Company, Lahore, Pakistan as Civil Engineer. These Jobs are for the Building Sector So you must have experience in Highway Projects. 

We have prepared a group on Facebook where you can get the alerts about Jobs in Lahore Knowledge Park Company, Lahore, PakistanIf you know any job opportunity in Private Sector both permanent Jobs and Jobs on contract basis you can contact us, you can inform us about the job.

If you are a fresh or experienced civil engineer living in Pakistan and seeking Civil Engineering Job in Highway Engineering than don’t post or share your CV here as we are not a part of the department and we are just sharing it so that you can get the opportunity to apply for this job.

Civil Engineering Jobs in AZ Engineering Associates Lahore for Punjab Highway Projects

AZ Engineering Associates urgently requires following staff for its Highway Projects in Punjab. Candidates meeting minimum criteria may send the latest CVs on hrazealhr@gmail.com

Civil Engineering Jobs in AZ Engineering Associates Lahore for Punjab Highway Projects

1. Name of Position : Resident Engineer

Qualification : B.Sc. Civil Engineering
Experience: 15 years in Highway Construction

1. Assistant Resident Engineer

B.Sc. Civil Engineering / B.Tech.
Experience : 07 years in highway construction.

1. Quantity Surveyors 

DAE Civil with 7 years experience

1. Site Inspectors

DAE Civil with 5 years experience

1. Lab Technicians 

DAE Civil with 5 years experience

Candidates must have completed minimum five mega highway projects. Candidate at time of interview will bring proof of at least completed five projects of mentionable size.

This Civil Engineering Jobs in  AZ Engineering Associates Lahore for Punjab Highway Projects is best opportunity for experienced Civil Engineers. All Civil Engineering jobs in AZ Engineering Associates Lahore for Punjab Highway Projects  is collected from different Newspapers on every Sunday and shared for our viewers so that that can apply for the job and get the employment in AZ Engineering Associates Lahore for Punjab Highway Projects as Civil Engineer. These Jobs are for the Highway Engineering Sector So you must have experience in Highway Projects. 

We have prepared a group on Facebook where you can get the alerts about Jobs in AZ Engineering Associates Lahore for Punjab Highway Projects If you know any job opportunity in Private Sector both permanent Jobs and Jobs on contract basis you can contact us, you can inform us about the job.

If you are a fresh or experienced civil engineer living in Pakistan and seeking Civil Engineering Job in Highway Engineering than don’t post or share your CV here as we are not a part of the department and we are just sharing it so that you can get the opportunity to apply for this job.

Malaysia to Experience Benefits of BIM and Cloud Technology in Mass Rapid Transit Project

The concepts of BIM Cloud technology is not new and we are already witnessing the utilization and application to these computing innovations in the field of construction. The construction projects are perceived as the most complex, unforeseen and way too pricey at times. The success of any construction projects to my experience depends more on pre-construct phase rather than actual site execution. Any mistake or over-look during the execution would not cost much when compared with an error at the initial and pre-construct phase.

Malaysia to be the First Country of Asia to Experience Benefits of BIM and Cloud Technology in Mass Rapid Transit Project

The construction projects always rely on the inputs from number of collaborators or team members including contractors, consultants, planning & acquisition sections, client supervisory departments and many others. Exchange of construction documents including drawings, design calculations and various specifications and standards has been a troublesome problem from pre-feasibility phase towards the completion of the project. The lack of communication and conveyance of information between these parties create series of erroneous mistakes that not only causes construction delays but also significantly produces monitory losses. 

Lets now discuss about the core concepts behind what we would going to discuss with you in detail of a mega project in Malaysia. The concepts we would deal is BIM and cloud technology that is exclusively used in the project under consideration. BIM is an acronym for Building Information Model; in a layman terms BIM is basically equivalent to construct a building or an infrastructure project in a digital world before actual execution at site. Yes!, BIM consists of a 3D model on actual scale dimensions including the actual geometry and architecture of a structure from the foundation to the top roof.  There are various softwares out there in the Market that would help you in creating a BIM for your project. 

BIM Model would help in understanding the steps or activities involved in a construction project, would help in tracking the design phases as well as execution phases, would help in 3d visualization of the project. One of a significant advantage of using BIM model is change management. The data of a project is stored in a BIM model file which means any significant change in one section or feature would be replicated automatically in all the sections and elevations contained therein. Not only this the change would be automatically transmitted to the collaborators of the project with the cloud technology. 

Now let me introduce to you the basic concept of cloud technology, actually this feature is just as simple that you instead of storing your data on a PC or laptop would store it on a cloud hosting server which could be accessed by all the team members with both mobile applications (iOS / appstore) or through interenet on laptops and pcs. 

Simulation of a building project is one other significant benefit for having a BIM in your project. Because BIM model is not merely consist of architectural data but also the actual structural elements like columns and beams, frames which would help you in simulating the project prior to the actual construction for ensuring the safety. 

In Kuala Lumpur, Malaysia has just experienced the benefits and remunerations of cloud-based collaboration through BIM Level 2. The 51 kilometer Klang Valley Mass Rapid Transit (KVMRT) project passes through Sungai Buloh-Serdang-Putrajaya (SSP) line. 

Microsoft Azure clouding hosting system of Microsoft Global ISV has Bentley Systems BIM applications that has helped to complete the project on-time and within budget, benefitting from a projected 35 percent productivity increase in the design, construction and operation of this infrastructure through seamless information sharing and collaboration. 

In a statement today, the company said the Azure-hosted Bentley Systems platform enabled MRT Corp to increase precision of construction, reduce instances of design rework and to improve safety standards by enabling seamless synchronization and information exchange between external vendors.

It has enabled all project disciplines to work dynamically using a federated model for coordinated design, despite the participation of numerous external vendors and decentralized information on this complex project, it said.

You would also love to read about the top innovative technologies in construction this year 2017. 

MRT Corp director of planning and design Poh Seng Tiok said one of the key challenge faced with any mega civil construction project is ensuring seamless information exchange, and real-time collaboration among stakeholders, regardless of the platforms they are using.

“The probability for error is high if information is not managed on a common data environment, especially in a highly collaborative project like ours.

“These types of errors could lead to construction delays and increased costs due to change orders and rework to rectify issues,” he said.

It is the first metro project in Asia to adopt BIM level 2, an advanced way of working that leverages digital collaboration and has become a standard for many leading governments for public-sector projects.

He said with this implementation, all parties involved can use their own 3D BIM models, but design information is shared through a common data environment, which enables any organisation to combine data with their own to create a federated BIM model.

“More importantly, embracing digital has enabled MRTC to improve our productivity, while also enabling our workers to acquire new skillsets necessary to adhere to the BIM standards which will be mandatory in civil engineering projects from 2020,” he said.

The KVMRT SSP line project has been selected as a finalist in the BIM Advancements in Rail and Transit category in Bentley’s 2017 Be Inspired Awards programme.

The annual awards program honors the extraordinary work of Bentley users advancing infrastructure design, construction, and operations throughout the world.

MRT’s project is among the 51 innovative projects which will be presented as part of related infrastructure forums at Bentley’s The Year in Infrastructure 2017 Conference, October 10 until October 12 in Singapore.

Bentley Systems Asia South regional executive vice president Kaushik Chakraborty said the KVMRT project is an example of how the world’s infrastructure projects are undergoing digital transformation through the power of cloud services to improve project delivery and asset performance.

“Together with Microsoft, we are pleased to see organizations tapping the power of the cloud to realize the potential of real-time business insights and collaboration to deliver greater efficiency in a highly complex industry,” he said.