Arches and Domes
The behavior of arches has been found very unsatisfactory during the earthquake. However, domes perform very satisfactorily due to symmetrical in nature. Arches during the earthquake have a tendency to separate out and collapse. however, mild steel ties if provided at the ends, their resistance can be increased to a considerable extent.
These are the worst affected part of any building during an earthquake. Studies reveal that this is mainly due to a differential displacement of connected floors. This can be avoided by providing open joints on each floor at the stair way to eliminate the bracing effect.
Beam Column Joints
Inframed structures the monolithic beam column connections are attractive so as to accommodate reversible deformations. The maximum moments occur at the beam-column junction. Therefore most of the ductility requirements should be provided at the ends. Therefore spacing of ties in the column is limited to 100mm center and in a case of beam strips and rings should be closely spaced near the joints. The spacing should be restricted to 100mm centre to centre only near the supports. In a case of columns, vertical ties are provided; performance of columns to earthquake forces can be amplified to a considerable extent. Steel columns for all buildings ie buildings more than 8 storey height should be provided as their performance is better than concrete column due to ductility behavior of the material.
Mortar plays an important role in masonry construction. Mortar possessing adequate strength should only be used. Studies reveal that a cement sand ratio of 1:5 or 1:6 is quite strong compared to economical. If reinforcing bars are put after 8 to 10 bricklayers, their performance to the earthquake is still better. Other studies have revealed that masonry in fill should not be considered as the non-structural element. It has been seen that in case of column bars are provided with joints at particular level about 600-700 mm above floor level at all storey should be spread out. It may be working as a weak zone at complete floor level in that storey.
As such if few measures are adopted during stages of design and construction of building their resistance to earthquake forces can be improved considerably. Though buildings cannot be made 100% earthquake proof their resistance to seismic forces can be improved to minimize loss of property and human life during the tremors.
Earthquake Resistant Building Construction With Reinforced Hollow Concrete Block
Reinforced hollow concrete blocks are designed both as load behavior walls for gravity loads and also as shear walls for lateral seismic loads, to safely withstand the earthquakes. This structural system of construction is known as the shear wall-diaphragm concept, which gives three- dimensional structural integrity or the buildings.
- Each masonry element is vertically reinforced with steel bars and concrete grouts fill, at regular intervals, throughout the continuous vertical cavities of hollow blocks.
- Likewise, each masonry element is horizontally reinforced with steel bars and concrete grout fills at plinth, sill, lintel and roof levels, as continuous RC bands using U-shaped concrete blocks in the masonry course, at recurring levels.
- A grid of reinforcement can be build into each masonry element without the obligation of any extra shuttering and it reduces the scope of corrosion of the reinforcement.
- As the reinforcement bars in both vertical and horizontal directions can be continued into the roof slab and lateral walls respectively, the structural integrity in all three dimensions is achieved.
In this construction system, structurally, each wall and slab behaves as a shear wall and diaphragm respectively, reducing the vulnerability of disastrous damage to the structure during natural hazards.
Due to the uniform distribution of reinforcement in both vertical and horizontal directions, through each masonry element, increased tensile resistance and ductile behavior of elements could be achieved. Hence the construction system can safely resist lateral or cyclic loading, when compared to other masonry construction systems. This construction system has also been proved to offer better resistance under dynamic loading, when compared to the other conventional systems of construction.
No extra formwork or any special construction machinery is necessary for reinforcing the hollow block masonry. Only semi-skilled labor is required for this type of construction.
It is faster and easier construction system, when compared to the other conservative construction systems. It is also cost-effective.
Architectural and other advantages
- This type of constructional system provides better audio and thermal insulation for the building.
- This system is durable and maintenance free.
- Studies on the comparative cost economics of RHCBM
There is a general apprehension that the RHCBM would be a costlier system, as it advocates reinforcing and use of concrete grout in the hollow spaces within the masonry. To dispel the apprehension, there elative cost economics of RHCBM structures are worked out in comparison with conventional construction systems.
This includes mid-level isolation system installed while the buildings are still being used. This new method entails improving and classifying the columns on intermediate floors of an existing building into flexible columns that incorporate rubber bearings base isolation systems and rigid columns which have been wrapped in steel plates to add to their toughness.
This is the first method of improving earthquake resistance in Japan that classifies the columns on the same floor as flexible columns and rigid columns, and it is the first casein west Japan the Kansai region of attaching rubber bearings by cutting columns on the intermediate floors an existing building. This method involves improving earthquake resistance while the buildings are still being used as normal operations.
There are three types of base isolation systems, depending on the location where rubber bearings are incorporated:
- Pile-head isolation
- Foundation isolation
- Mid-level isolation
Earthquake Resistance Using Slurry Infiltrated Mat Concrete - SIMCON
Following the devastating earthquakes in Turkey this summer that killed as many as 20,000 people and injured another 27,000, images of survivors trapped beneath the rubble of collapsed buildings appeared daily in news reports worldwide. However, a North Carolin a State University engineer is developing a new type of concrete to help prevent such scenes from happening again. Because it's reinforced with mats made of thousands of stainless steel fibers injected with special concrete slurry, the new material, called Slurry Infiltrated Mat Concrete (SIMCON), can sustain much higher stress loads and deformations than traditional concrete. Tests how that concrete buildings or bridges reinforced with SIMCON are far more earthquake- resistant and less likely to break apart in large chunks that falloff and cause injury to people below.
If extreme stresses cause SIMCON to fail, its mass of fibers and concrete doesn't collapse in the same way traditional concrete does. Instead of large chunks breaking and falling from a structure, the material crumbles into small, harmless flakes. This controlled form of failure is a key advantage of SIMCON. Because failure is inevitable in all structures, engineers must design buildings and bridges to fail in the safest way. In conventional concrete structures, this is achieved through the use of steel reinforcing bars--rebars--that give the concrete tensile strength it would otherwise lack. For safety and design reasons, the concrete is designed so that the rebars will fail before the concrete does. Unfortunately, many structures have not been designed to sustain the powerful stresses caused by earthquakes. When such extreme stresses occur, the concrete can crack, explode and break away from the rebars, causing the structure to collapse.
Concrete foundations for greater stability
- Wooden columns treated with tar or pitch to protect against humidity, concreted into the ground with nails embedded in the wood at the base to give extra anchorage.
- Using concrete wall bases to prevent humidity affecting the wood and the canes in the walls.
- Careful jointing between columns and beams to improve structural integrity.
- Canes woven in a vertical fashion to provide greater stability.
- Lightweight metal sheet roofing to reduce danger of falling tiles.
- Nailing roofing material to roof beams; tying of beams and columns with roof wires.
- Incorporating roof eaves of sufficient width to ensure protection of walls from heavy rains.
However the builders and constructors should adopt the coal provisions in all the future construction, as prevention is better than cure. On the light of avoiding the risk, this may not be an impossible task as earthquake resistant measures in building involves only 2% - 6% additional cost depending on the type of building. Using construction techniques like Simon and RHCBM can not only mitigate earthquake effects but also are cost effective.
While we have seen about the reasons for an earthquake, and how earthquake resistant building construction is different, reinforced concrete buildings and other things in our previous blog let us see more on the roles of floor slabs and masonry walls and much more in this blog.
Roles of Floor Slabs and Masonry Wall
The floor slabs are horizontal elements, t facilitates functional use of buildings. Usually, beams and slabs at one storey level are cast together, but, in residential multi storied buildings, the thickness of slab will be only about 110 mm -150 mm. when beams bend in a vertical direction during earthquakes, these thin slabs bend along with them. When beams move in the horizontal direction, the slab usually forces the beams to move together with it.
However, in most of the buildings, the geometric distortion of the slab is insignificant in the horizontal plane; the behavior is known as rigid diaphragm action. After columns and floors in an RC, a building is cast and the concrete hardens, vertical spaces between columns and floors are usually filled in with masonry walls to separate floor area into functional spaces. Usually, these masonry walls are called infill walls, are not connected to surrounding RC beams and columns. When the columns receive horizontal forces at floor levels, they try to move in the horizontal direction, but masonry wall tends to resist this movement.
Due to the heavy weight and thickness, these walls develop cracks once their ability to carry horizontal load is exceeded. Thus, infill walls act like sacrificial fuses in the buildings, and they develop crack under severe ground shaking but help share the load a load of beams and columns until cracking.
For a building to remains a feuding earthquake shaking columns which receive forces from beams; should be stronger than beam sand foundations that receive forces from columns and should be stronger than columns. While adding the connections between beams and columns, columns and foundations should not fail so that beams can safely transfer forces to columns and columns to foundations.
When this strategy is adopted in the design, the damage is likely to occur first in beams. When beams are detailed correctly to have large ductility, the building as a whole can deform by large amounts despite the progressive damage caused due to consequent yielding of beams. If the columns are made weaker, then localized damage can lead to the collapse of building, though columns at storey above remain almost undamaged.
Earthquake Resistant Building
The engineers do not effort to make earthquake proof buildings that will not get damaged even during the rare but strong earthquake; such buildings will be too robust and also be too expensive. Instead, engineering intention is to make buildings earthquake resistant, such building resists the effects of ground shaking, although they may get damaged severely but would not collapse during the strong earthquake. Thus, a safety of peoples and contents is assured in earthquake resistant buildings and thereby, a disaster is avoided. This is a major purpose of seismic design codes through the world.
Earthquake Design Philosophy
The earthquake design philosophy may be summarized as follows:
- Under minor, but common shaking, the main members of the building that carry vertical and horizontal forces should not be injured; however, the building parts that do not carry load may carry on repairable damage.
- Under modest but occasional shaking, the main member may sustain repairable damage, but the other parts of the building may be damaged such that they may even have to be replaced after the earthquake.
- Under strong but rare shaking, may sustain severe - even irreparable damage, but the building should not collapse.
Hence, after minor shaking, the building will be operational within a short time and repair cost will be small and after moderate shaking, the building will be operational once the repair and strengthening of the damaged main members are completed. But, after a strong earthquake, the building may become dysfunctional for further use but will stand so that people can be evacuated and property recovered.
The consequences of damage have to be kept in view in the design philosophy. For example, important buildings like hospitals and fire stations play a critical role in post-earthquake activities and must remain functional immediately after an earthquake. These structures must sustain very little damage and should be designed for a higher level of earthquake protection. The collapse of dams during an earthquake can cause flooding in the downstream reaches, which itself can be a secondary disaster. Therefore, dams and nuclear power plants should be designed for a still higher level of earthquake motion.
Remedial Measures to Minimize the losses due to Earthquakes
Whenever a building project is prepared and designed, the first and the most important aspect of a design is to know the zone to which this structure is likely to rest. Depending upon these, precautionary measures in structural design calculation are considered and structure can be constructed with sufficient amount of resistance to earthquake forces. Various measures to be adopted are explained point wise, giving emphasis to increase earthquake resistance of buildings.
The records of various earthquake failures reveal that unsymmetrical structure performs poorly during an earthquake. The unsymmetrical building usually develops torsion due to seismic forces, which causes the development of crack leading to a collapse of a structure. The building, therefore, should be constructed rectangular and symmetrical in plan .If a building has to be planned in irregular or unsymmetrical shape, it should be treated as the combination of a few rectangular blocks connected with passages. It will avoid torsion and will increase the resistance of building to earthquake forces.
IS code recommends that as far as possible entire building should be founded on uniform soil start a. It is essentially to avoid differential settlement. In case if loads transmit on a different column and column footing vary, the foundation should be designed to have a uniform settlement by changing foundation size as per code conditions to have a loading intensity for consistent settlement.
While Raft foundation performs better for seismic forces. If piles are driven to some depth over which a raft is constructed the behavior of foundation under seismic load will be far better. Piles will take care of differential settlement with raft and resistance of the structure to earthquake forces will be very huge.
Provision of Band
However, IS code recommends construction of concrete band at lintel level to oppose earthquake. The studies revealed that building with the band at lintel level and one at plinth level improves load carrying of building to earthquake tremendously. It is recommended here that if bands are plinth level, skill level, lintel level and roof level in the case of masonry structure only, the resistance of building to the earthquake will increase extremely. The band at sill level should go with a vertical band and door openings to meet up at lintel level. Hold fast of doors can be fitted with their ill band. In the case of the earthquake of very high intensity or large duration only in fill wall between walls will fail to minimize casualties and sudden collapse of the structure. People will get enough time to escape because of these bands.
An earthquake is a vibration, which sometimes violent the earth’s surface that follows a release of energy in the earth’s crust. This energy can be generated by a unexpected dislocation of segments of the crust, by a volcanic eruption or even by a manmade explosion. The dislocation of the crust causes most critical earthquakes. The crust may first bend and then the stresses exceed the strength of rocks, they break. In the process of breaking, the vibrations called seismic waves are generated. These waves travel outward from the source of the earthquake all along the surface and through the earth at unreliable speeds depending on the material through which they move. These waves cause disasters on the earth’s surface.
However, no structure on this planet can be constructed 100% earthquake proof; only its resistance to earthquake can be amplified. While treatment is required to be given depending on the zone in which the particular site is located. Though earthquake occurred in the recent past have raised various issues and forced us to think about the disaster management; it has now become essential to think right from planning a proper stage to completion stage of a structure to avoid failure or to diminish the loss of any property. Not only this, but once the earthquake has occurred and disaster has taken place; we have to know how to use the debris to construct economical houses using this waste material without affecting their structural stability.
How earthquake resistant construction is Different?
Since the magnitude of a future earthquake and shaking intensity expected at a particular site cannot be predictable with a reasonable accuracy, while the seismic forces are difficult to quantify for the purposes of design. Further, the actual forces that can be generated in the structure during an earthquake are very large and designing the structure to respond elastically against these forces make it too expensive.
Therefore, in the earthquake resistant design post yield in elastic behavior is generally relied upon to dissipate the input seismic energy. Thus, the design forces of earthquakes may be only a fraction of maximum (probable) forces generated if the construction is to remain elastic during the earthquake. For instance, the design seismic for buildings may at times be as low as one tenths of the maximum elastic seismic force. Consequently, the earthquake resistant construction and design does not aim to accomplish a structure that will not get damaged in a strong earthquake having low probability of occurrence; it aims to have a structure that will perform appropriately and without collapse in the event of such a shaking.
Ductility is the capacity of the structure to undergo deformation beyond yield without losing much of its load carrying capacity. However, the higher is the ductility of the structure; more is the reduction possible in its design seismic force over what one gets for linear elastic response. Ensuring ductility in a structure is a major concern in a seismic construction.
Effect of Earthquake on Reinforced Concrete Buildings
In recent times, reinforced concrete buildings have become common in India. A typical RC building is made of horizontal members (beams and slabs) and vertical members (columns and walls) and supported by foundations that rest on the ground. The system consisting of RC columns and connecting beams is called a RC frame.
The RC frame participates in resisting earthquake forces. While the earthquakes haking generates inertia forces in the building, which are again proportional to the building mass. Since most of the building mass is present at the floor levels, earthquake induced inertia forces primarily develops at the floor levels. These forces travel downward through slabs to beams, beams to columns and walls and then to foundations from where they are dispersed to the ground. As the inertia forces accumulate downward from the top of the building. However, the columns and walls at the lower storey experience higher earthquake induced forces and are therefore designed to be stronger than the storey above.
A paper battery is an electric battery which was engineered to use a spacer formed largely of cellulose -the major constituent of paper. This helps to incorporates nano-scale structures to act as high surface-area electrodes to perk up conductivity.
In addition to being unusually thin, paper batteries are more flexible and environmentally-friendly compared to other batteries. These batteries allow integration into a wide range of products; and their functioning is similar to conventional chemical batteries with an significant difference that they are non-corrosive and do not require widespread housing.
- This battery produces electricity in the same way as the conventional lithium-ion batteries, but all the components that have been incorporated into are lightweight, flexible sheet of paper.
- These devices are formed by combining cellulose with an infusion of aligned carbon nanotubes.
- The electrolyte and the ions that carry the charge can be varied depending the use of the battery.
- A conventional Li-ion battery can be incorporated in cellulose-nanotube composite as shown in the blow image.
The creation of the Paper Battery drew from a diverse pool of disciplines, and these batteries require expertise in materials science, energy storage, and chemistry. However, in August 2007, a research team at Rensselear Polytechnic Institute Led by Drs. Robert Linhardt, John H. Broadbent, Pulickel M. Ajayan, Omkaram Nalamasu with a joint meeting in Material Science and engineering developed the Paper Battery, which is also known as Nano Composite Paper. In December 2009,Yi Cui and his team at Stanford University successfully made an actual prototype that gave a terminal voltage of 1.5 V.
- NICD rechargeable battery using nickel oxide hydroxide and metallic Cadmium as electrodes.
- Terminal voltage of 1.2V.
- It is rigged, high specific power (150W/kg), this battery life will be long and light.
- This battery is used in UPS, portable power tools, flashlights, photography equipment, emergency lighting, and portable electronic devices.
- However disadvantages include Memory effect, Environmental hazards, and cost.
- This battery is constructed using graphite rod, Lithium cobalt oxide(or Lithium manganese oxide) as electrodes and lithium hexafluorophosphate (LiPF6) as electrodes.
- Has Terminal voltage of 1.2V
- Rugged and high specific power (150W/kg), with log life, and light.
- Used in UPS, portable power tools, Photography equipment, flashlights, portable electronic devices, and emergency lighting.
- While the disadvantages include Environmental hazards, cost and Memory effect.
Issues with Conventional Batteries:
- Low specific power compared to fuels
- High charging Time
- Weight and size
- Explosion, corrosion, leakage
- Environmental hazards
- High Cost
- Terminal voltage constraints
li-ion Paper Battery
While the nanotubes, which colour the paper black, will act as electrodes and allow the storage devices to conduct electricity. The device functions as both a lithium-ion battery and a super-capacitor, which stores charge like a battery. But it has no liquid electrolyte. However the paper battery provides a long, steady power output as against a conventional battery burst of high energy. The ionic liquid electrolyte that is soaked into the paper is a liquid salt and contains no water, so it won't freeze or boil. However, the researcher are going around the world to replace this ionic electrolyte with body fluids, sweat, blood, etc.
The materials required for the preparation of paper battery are:
- Copier paper and Carbon nano inkCarbon of nano rods, surface adhesive agent and ionic salt solutions. Whereas Carbon nano ink is spread on one side of the paper.
- However, the paper is kept in the oven at 150 degree Celsius. This evaporates the water content on the paper. The battery is then ready and would provide a terminal voltage enough to power an LED.
- Light, rugged, flexible, van be be rolled crunched, cut, made into any shape.
- The nano composite paper is compatible with a number of electrolyte, like urine, blood, sweat, etc.
- If we stack 500 sheets together in a ream, that's 500 times the voltage. If we rip the paper in half then we cut power
- by 50%. so we can control the power and voltage issue
- Non - toxic and hence can be used to power pacemakers and RF tags
- It is very useful where burst of energy is required for operation like mostly electric vehicles.
- The electrolyte contains no water, thus there's nothing in the batteries to freeze or evaporate, potentially allowing operation in extreme temperatures.
- It is environment friendly.
- Paper Battery would be the answer to the electrical Energy storage Problems.
However, the composition of these batteries is what sets them apart from traditional batteries. We all know that paper is abundant and self-sustaining, which makes paper cheap. Though disposing the paper is not an inexpensive task since paper is combustible as well as biodegradable. But, using paper gives the battery a great degree of flexibility. The battery can be bent or wrapped around objects instead of requiring a fixed casing. Also, being a thin, flat sheet, the paper battery can simply fit into tight places, reducing the size and weight of the device it powers. While the use of paper increases the electron flow which is well suited for high performance applications. The paper used in paper batteries can be an supplement to improve its performance characteristics.
Patterning techniques such as photolithography, wax printing, and laser micromachining are used to create hydrophobic and hydrophilic sections on the paper to make a pathway to direct the capillary action of the fluids used in batteries. Similar techniques can be used to create electrical pathways on paper to create paper electrical devices and can integrate paper energy storage.
At present, the devices are only a few inches across and they have to be scaled up to sheets of newspaper size to make it commercially viable. Carbon nanotubes are expensive .However, the idea is still in the labs and a commercially viable paper battery will take at least 40- 70 years to come into reality. While the researchers in nanotechnology to mass produce nanotubes is promising.
- Pace makers (uses blood and electrolyte)
- Devices in space Shuttles
- Used as alternate to conventional batteries in gadgets.
- Powered smart cards RF id tags, smart clothes.
- Disposable medical devices - like Single use delivery and diagnostic devices could have Power Paper incorporated into their construction to allow for sensors and smart labels.
- Paper battery is set in iontophoresis patch. It helps to deliver functional drugs, local anesthesia, anodyne, antichloristic, etc into the skin.
- Paper battery could one day power motor vehicles and aircrafts and replace the conventional fossil fuel based engines with electric motors.
However, the possible applications for paper batteries derives from their important advantages as compared to conventional battery technologies. These can be made in virtually any shape and size to meet the requirements of each application. while the batteries are rechargeable and have reduced cost and weight less which in itself may give birth to new applications. Paper battery could solve all the problems associated with electrical energy storage. However, the reality is still very far away, though the researches are promising.
No project or project management can be meaningful without this. If in case it is a Government work then the manager should get his budget fixed on monthly basis, and on the basis of work done or minimum to be fed at site and depending on the decision of higher authorities plays vital role. Key to measure financial planning lies in taking all above actions and planning to execute proper suitable measures at appropriate times to make sure that individual inputs are achieved to the maximum and capital investment kept at the lowest level.
Quality of work at any construction site is most important activity that every manager should always struggle to improve. While training the staff should also be provided to update the quality control measures and it should become part of the work culture. However, the site laboratory be established to check the quality of concrete.
Tests should be analyzed at site based on the size of job. Combine design should be prepared based on the latest code and to produce the concrete of desirable strength. Compaction of concrete be given more attention before final setting. Latest guidelines issued by IRC and MORT&H be followed for systematic quality assurance. Quality assurance on ground improve the aesthetic of structures.
Safety of employees at site should be observed very seriously and at every level. All the workers be given briefing about the safety requirements based on the site hazards. Especially when the simply supported structure is attempted on deep gorge, suitable arrangement should be made to avoid any accident at site during insitu casting of superstructure. Also in case of foundation if the deep excavation is involved, the quality of surrounded soil be kept in view. There are incidents where few workers got buried in deep excavation due to sudden slide, this should be taken care. In case the well foundation is being attempted using double drum winch care need to be taken during grabbing process. During the diving process the proper coordination needs to be made between the diver and attendant to intimate about the problems if any, for which local signaling arrangements used, this can be finalized at site based on convenience. In case the pneumatic sinking is being used for well foundation, following safety measures, may be observed:
- Slow decompression
- Accelerate circulation of air
- Replacement and spare equipment
- Lighting inside working chamber
- Signaling arrangement
- Caution about incidental loading
These precautions should be seriously followed to avoid any catastrophes at site. Safety management is also important in case on staging shuttering for superstructure. There are cases in the past where the collapse of shuttering/staging has led to loss of life. This needs check in before casting the superstructure. In case steel truss is being used as a staging arrangement, design and launching arrangement be thoroughly checked.
Document management during the contract is an art in itself. Proper and systematic management of documents is utmost requirement for department as well as contractor. All the details should be property vetted by both the parties. Better documentation will avoid any disputes during the currency and after completion of contract (i.e arbitration cases areavoided). This needs special attention of the managers of both sides. Most of the cases being dealt by the arbitrator in our country, due to lack of understanding between two parties which, are further affected by improper documentation. In fact better documentation reflect the system of management in any project. Control estimate is required to be prepared annually to assess the job position. This should include work done till date and balance work in terms of money. This will be a guiding principle to progress the job in later period till completion. This practice is a must in all major bridge under construction. As project management has evolved, documentation has become a key skill particularly as projects become more complex and difficult. Organized documentation is the best defense against claims. Documentation that every project manager must have at their disposal are as follows:
- Proposal and Bid Estimates – These documents describe how the contractor envisioned the construction of the project and his plan to accomplish the work. It includes information about costs and schedule as well as construction methods.
- Project Schedule - This is one of the most overlooked project records and it can provide the best documentation in a claim situation. The original baseline schedule sets the mark for monitoring the effects of any delays or unforeseen project disruptions.
- Project Change orders – Any variances from the original contractual requirements must be documented and separated from the original scope of work requirements. Daily reports, time sheets, letters of correspondence and meeting minutes or any other documentation discussing agreements made between parties should be readily available.
Manager should put the engineers, to activities they can perform better. Individual differences should be studied in detail to assign the suitable job to engineers, administration and account staff. Manager should be a good Psychologist to assign the work based on the inclination of the people at work. A considerable free hand be given to see what an individual can produce. He should be guided from time to time and work be kept on progress.
Decision making circulated, critical activities be cleared by manager after proper deliberations. Also care must be taken to select a new entrant suiting to the job for requirement.
With the changing scenario and the urgent need to manage the bridge project effectively. Construction management is basically a tool to complete the project effectively within fixed amount but in less time. Manager should have knowledge sequence of all the activities. Decision making for both sides the contractor and the client needs to be fast and time bound otherwise the project will get delayed which will have cost overrun. Control in form of reviewing monitoring has a catalyst effect to boost the development.