An Overview of Building Repairs, Retrofitting & Maintenance

Infrastructure is the current buzzword in our country and is considered an important parameter of development. Maintenance, repair and ensuring the serviceable condition of structures assume prime importance. Strengthening, retrofitting may also be warranted in view of changed usage pattern of the structure or change in I.S Code provisions. Construction boom in late seventies & eighties has left behind a legacy of deteriorating structures which needs to be attended to. This offers a challenge to the Building Repair Industry. To investigate the deficiencies and reasons of deterioration for recommending remedial measures to be adopted, specialist services are now available and include:

We Give Special Attention to Heritage Structures

In case of strengthening, conventional or non-conventional solutions may have to be adopted considering the chemistry of repair material, civil engineering aspects, energy saving, water conservation, air-conditioning etc. Heritage structures need special attention in order to maintain the heritage value. Knowledge of construction material used and the historical value of structure need to be taken into account. The following types of structures need to be addressed from repairs/rehabilitation point of view: High rise structures, marine & offshore structures, bridges & flyovers, industrial plants, airports, ports & jetties, Water Storage Reservoirs, Pipelines etc.

Guniting / Shotcreting

Conventional concrete repairs like guniting / shotcreting are now overtaken by application of structural repair mortars. Like ready-mixed concrete, repair mortars are now available in factory made dry forms that are trowel able and of pourable grade which enhance the quality, speed and economy of repairs. These mortars are spray applicable with the help of special guns and nozzles. It is easy to control water/cement ratio in such mortars. It eliminates the need to check individual ingredients of the repair mortars. Grouts and admixtures are available to achieve tailor made properties for concretes and mortars. Under water repairs are possible with such repair materials. Certain admixtures are used to alter the Rheology (flow properties) of concrete in order to achieve dense and durable concretes.

How we Carry Out Crack Repairs?

Crack repairs can be done by surface sealing with specialized sealants, application of coatings or injection grouting. Crack repair by epoxy resin is an important aspect of concrete repair of superstructures as well as foundations. It is possible to carry out grouting against water pressure using polyurethane grouts which expand and seal the cracks. Specially engineered sealants like polyurethane sealants, polysulfide sealants, epoxy sealants, silicone sealants are also used for sealing joints and crack repairs.

Protective coatings are gaining widespread importance from both waterproofing as well as protection point of view. Acrylic, silicone, epoxy coatings are used for improvement of durability of concrete in structures by preventing environmental attack. The importance of surface preparation prior to coating application has given rise to widespread usage of hydro-jetting equipments for cleaning the surface. Glass fiber cloth/mesh is used to improve the tensile strength of coatings and improve their durability.

Seismic disasters like the one in Gujarat gave rise to structural strengthening of elements by using Advanced Composite fiber Materials (ACM) like carbon, glass and Kevlar. The idea is to confine the structural member using these composites and enhance the load carrying capacity. These are light weight materials having high strength/weight ratios. Fabrics of the above composites are bonded to the structural member with epoxy saturant to selectively strengthen the member in shear, flexure etc. In seismic retrofitting, this technique is widely used. ACMs have a bright future in the field of structural strengthening. Design codes now exist in USA and UK. Their usage is now accepted world wide as a cost effective measure of providing strength to a structure.

In conclusion it may be stated that newer materials, techniques and equipments are gaining widespread acceptance in repair & retrofitting technology. Improvement in technology is fuelling further growth of this business.