SOME MAINTENANCE ISSUES IN CIVIL ENGINEERING WORKS

SOME MAINTENANCE ISSUES IN CIVIL ENGINEERING WORKSDr K M SoniChief Engineer, WZ-I, CPWD, Mumbai

MaintenanceMaintenance is a required set of works undertaken to upkeep, restore or improve an entity.

Objective of the MaintenanceThe objective of the maintenance is to keep the entity in good operating conditions, sometimes to improve it or restore it to its originality.

Classification of MaintenanceAs per CPWD maintenance manual, maintenance is classified as; routine or day-to-day maintenance, annual repairs and special repairs. Additions and alterations, restoration and retrofitting works are carried out occasionally as per the requirements. Hence these are not classified in general maintenance.

Quality of MaintenanceIn maintenance works, it is very difficult to satisfy a customer as the level of satisfaction always goes up as the level of maintenance goes up.Quality must meet the requirements of the customer and should satisfy the customer.Quality and specifications are entirely different. However once specifications are fixed, the work conforming to the specifications must meet the quality standards. Still sometimes quality is misunderstood to be same as specifications.

Foundation of MaintenanceA Structure on weak foundation always remains weak. The foundation of the maintenance is the construction and that of construction, planning and execution.Poorly planned and poorly executed works will never lead to satisfaction to the users during maintenance period. Thus good planning and quality construction are the basic requirements of the quality maintenance.

One brick wall ConstructionLoad bearing structures with external walls of one and half brick wall or more was adopted before 1940s in many places. One brick wall construction was adopted thereafter for economizing the construction. Total brick component in a building costs about 10.5% as per CPWD cost index norms and therefore as rough calculation additional half brickwork may cost about 7 to 8% of the building cost. Practically it is observed that one and half brick wall construction requires less maintenance compared to one brick wall construction.

Some of the problems faced in one brick wall constructionSometimes exposed brickwork is provided in one brick wall. Class 75 bricks are normally used in construction. These bricks and mortar even if pointing has been done, particularly after 10-15 years absorbs considerable water (Permissible limit of water absorption in case of such bricks is 20% by weight). Ingress of moisture starts from weak/deteriorated portions of the plaster and leads to seepage inside the houses and results in peeling of paint/distemper and weakening of plaster apart from making rooms uncomfortable for living due to foul smell. Also, it is difficult to assess exact location of ingress of water. No exposed brickwork should be provided in one brick wall. One and half brickwork cuts off the joints.

One brick wall ConstructionOne brick wall construction gets disturbed while fixing clamps in rain water pipes and stacks particularly with the methods prevalent in the country and also in case of chase cuttings for the services creating small cracks, which become the source of seepage. Shafts are therefore highly vulnerable to seepage in one brick wall construction. Such problems are minimum in one and half brick wall construction.

One and half brick wall ConstructionOne and half brickwork is also economic considering life cycle of the structure. Load bearing construction is considered to be lasting for about 50 to 60 years while one brick wall construction has shown deterioration even in 25 to 30 years while it has been observed that one and half brick wall construction is still in good conditions even after 60 to 70 years and at some places even after 100 years. Repair, rehabilitation and reconstruction of one brick wall construction require a huge expenditure after such period.

One and half brick wall ConstructionAlso, one and half brick wall construction provides better insulation than one brick wall construction making it to be more energy efficient both in summer as well as in winter.

External PlasterNormally brickwork is plastered on outer surface with cement mortar of mix 1:6. Places remaining moist for longer periods like portion up to DPC level, external surface of the parapet wall, shafts and portion above chajjas get deteriorated fast. On deterioration, it becomes expensive and very difficult to re-plaster the surfaces except plinth. In shafts, plastering is extremely difficult in occupied quarters and due to number of pipes in the shaft. Plaster in such places should be adopted with a richer mix, say 1:4 and with chicken wire mesh/ PVC net below the plaster or permanent finish or stone/tile cladding should be provided in such places.

Construction without ParapetSuch construction was adopted in government buildings during late seventies and early eighties with the provision of projected roof slab without rain water pipes at many places. A drip course was provided in slab projection and water proofing treatment done over the roof. Since material used in the water proofing and slab are different and drip course has a limited life, water started flowing below slab in the projected slab portion.It not only resulted to seepage at the junction of wall and the slab but also started rusting the reinforcement of the slab and spalling of concrete. Maintenance and repair of such slab is very difficult and expensive. Parapet should always be provided along with rain water pipes.

Construction with CTD BarsCTD bars were adopted due to high strength criterion to have an economy in construction. Practically it has been observed that the construction with mild steel is not showing distress even after 60- 70 years but structures with CTD bars has shown distress even after 20-25 years of the construction. Poor quality enhances the problem.Such construction has proved to be very costly as it has resulted in spalling of concrete and distress in beams, columns and slabs. Repair and rehabilitation of RCC members has become very costly and still not so durable. Maintenance of such structures is very difficult and expensive. Sometimes it is better to demolish such structures and rebuild them.

Narrow ShaftsSometimes very narrow and covered shafts are provided without any considerations to maintenance. Such design results in inherent maintenance problems. Sometimes shafts are so narrow that even water supply pipes and stacks cannot be accommodated in the shafts. Whenever due to any problem sewer leaks, it overflows over water supply pipes and in case water supply pipeline also require repair due to leakage, intermixing is also there till pipes are repaired. In such shafts, even plumber and other labour do not want to work. Easy access to the shaft is also important for good maintenance. At number of places, access to shafts is through toilets of the quarters particularly in multi storeyed government hostels/housing. Occupants many times do not allow maintenance staff to enter their toilets.

Narrow ShaftsSometimes narrow projected slabs are provided in the shafts where one cannot even stand in case of overflow and such slabs start showing distress due to corrosion and spalling of concrete in RCC projected slab. Sometimes shaft are provided in the central portion in the buildings with rooms all around the shaft. In case of blockade, it becomes very difficult to maintain them and foul smell can be noticed in such design almost throughout the year. In fact, planning and execution of plumbing services is considered of least importance while efficiency of a maintenance engineer depends upon plumbing services.

Expansion JointsExpansion joint in a building has a specific role but many a times it is filled up with mortar or debris and no more it acts like an expansion joint. In such circumstances cracks start near expansion joints. Also treatment of expansion joint is not done properly and seepage/leakage can be seen near expansion joints. So far no standard design of treatment of expansion joint has been evolved. When tile work is done, pieces are many times fixed near expansion joint on floor, which are easily dislodged. In such places either stone like marble, granite etc. should be fixed or full tile should be properly fixed. Improper treatment of expansion joint poses a maintenance problem particularly during rains.

Water Proofing In some places, conventionally mud phuska treatment was being used. The soil used in mud phuska treatment was clayey in nature i.e. impervious in nature and when bhusa (straw) was mixed in clay, it was preventing cracks as bhusa was acting as reinforcement in the soil. Mixing was done in manner to make it homogenous having uniform moisture content. But now the technology has been failing because of use of pervious soil in place of impervious clay and also due to non-uniform mixing i.e. due to poor selection of soil and poor workmanship. The mud phuska treatment also provided good insulation properties. Integral waterproofing (coba treatment) has been adopted now in many places but if it is not done in proper sequences and if adequate curing is not done, minor cracks cannot be prevented. In such circumstances, even newly constructed buildings seepage and leakage can be observed. Even chemical treatment done thereafter on such inferior work does not last long. In some cases, bituminous sheet is laid on roof starting from the parapet and continuing on the roof. Since the sheet comes under tension at the junctions like at the junction of parapet and roof, cracks start at the junction after some time and seepage starts. The sheet should be laid separately on roof with covering flat surface and some portion of vertical surface and separate on vertical surface with overlap on the sheet laid on horizontal surface.

Water Proofing So far main emphasis was given on water proofing materials rather than on RCC. Probably due to the idea of the economy, the slab was cast without slope and slope was provided in water proofing materials. Once, water proofing material fails, water get stagnated on the slab and since evaporation is not easy because of overlay of water proofing material and brick tiles, seepage is common feature in such construction. Therefore, the need is to give slope in slab may be on the top so that aesthetic is not disturbed from inside of the building. Water proofing treatment of uniform thickness can then be provided over the slab, even if it is little costly.

Plinth Protection WorksProper plinth protection works not only protects foundation but also stops moisture to travel inside the brickwork up to DPC level. If the quality of the plinth protection is inferior, it defeats the sole purpose. Mostly brick aggregates are specified in plinth protection works. The quality and life of plinth protection works with such specifications is not satisfactory. It is essential that specifications of plinth protection be modified to RCC or stonework. Vertical plinth protection with stonework or permanent plaster or at least neat cement also helps to prevent moisture ingress due to capillary action. Damaged plinth protection damages plaster up to DPC level at a very fast speed.

Quality of Maintenance WorksTo achieve quality in any work, one mustKnow, understand and agree to the requirements of the job.Know how to do the job and why it is being done.Have the knowledge of materials, process and equipment to do the job.Know what to do when the things go wrong.For above, it is essential that orientation and development training to the engineers/supervisors is imparted in new materials, methods, and machinery in a systematic manner.

Quality should not be expected ifWork is accepted not up to the standard may be because of urgency or any other reason.Decision on rejecting the substandard work or taking action against the contractor for a substandard work is delayed.The responsibility is passed on to others stating you do it somehow.Work is suspended till somebody else takes over the charge.Others are only blamed before finding out what he could do to solve the problem.One Refuses to listen others and solve the problems.

Capacity BuildingPeople engaged in maintenance have the right training, placement, and knowledge.Proper contractors are selected for the work.Co-ordination and feedback system is available.A system is designed to guide the juniors in which architects, engineers, quality managers and trainers are involved.

ConclusionQuality in maintenance works is a function of the architectural planning, quality during construction, selection criterion of the contractor, and attitude of the seniors towards guidance to their juniors, maintenance management policy and training during maintenance. Good maintenance requires engineering and management skill. Best results can only be achieved in maintenance if the maintenance is taken up in team spirit.