Common damages in structures

There are different common damages in structures, some can compromise the structure, and some affect the aesthetics of one. In this article we will define the concept of damage recognized by American Concrete Institute (ACI) and the types of damages, which we find in the concrete and masonry structures commonly.

Guide for Assessment of Concrete Structures before Rehabilitation (ACI 364.1R-19) defines damage as the changes in capacity of an existing structures resulting from events, such as loading and displacements.

What are the types of damages in structures?

With the past of the time the buildings may present damages due to aging of materials by the exposure of environment conditions and even defects in the design and/or construction.

The concrete and masonry structures can suffer damages. These damages can be minor or major ones. A major damages affect to a major element of a building which can even cause destruction of all or some part of its. But a minor damage, generally, can affect to building´s appearance, its value or its function without compromising the integrity of the structure.

What are the types of common damages in concrete structures?

The concrete structures can suffer the following main types of damages: scaling, spalling, curling, cracking, crazing, blistering, delamination, dusting and efflorescence.

Scaling occurs as a result of freezing and thawing cycles, when the finished surface flakes or peels off; starting as small patches and extending to large areas later. This problem affect, principally, to outside concrete flat work such as sidewalks, patios and driveways.

Spalling is the breaking of layers or pieces of concrete from the surface of a structural element, it can occur owing to many causes such as high changes of temperature in the concrete, steel corrosion and others. Generally there are four types of concrete spalling: the first is surface spalling that affects to concrete surface, the second is corner break- off or sloughing off which occurs in the later stages of a fire and affects concrete on wall corners. Other dangerous spalling is explosive spalling, when pieces of concrete are separated forcibly at high pressure. And the last type is corrosion spalling, this one occurs when reinforced bars rust, increase their volume and detach their concrete cover.

The main cause for scaling and spalling is penetration of water through concrete surface, making steel gets corroded. Other causes can be the use of non-air entrained concrete mix, inadequate curing and the use of low strength concrete.

Curling is the upward or downward bending of the edges of a concrete element, then the concrete member gives a cupped shape. It occurs due to the difference in temperature or moisture content between slab surface and slab base.

Cracking is a separation of a structural element or material into two or more pieces under the action of stress, as the result of many factors such as drying shrinkage, improper mix design, subgrade settlement, applied loads, insufficient curing, omission of expansion and contraction joints, thermal contraction and restraint to shortening, generally the concrete have low tensile strength. Generally this damage is created by some other cause and accompanies damage types mentioned before.

Crazing is the formation of closely spaced cracks in an uneven manner. This damage can occur due to rapid hardening of top surface of concrete, because of insufficient curing of this, high temperature or due to the mix contains excess water.

Blistering is the formation of hollow bumps of different sizes on concrete surface. This damage occur due to entrapped air under finished concrete surface and it can be caused due to improper finishing, excessive vibration of concrete mix or presence of excess entrapped air in mix and excessive evaporation of water on the top surface of concrete.

Delamination is similar to blistering, but also top surface of concrete gets separated from underlying concrete. Delamination could occur when top layer of concrete to harden before underlying concrete is hardened and the water and air bleeding from underlying concrete are struck between these two surfaces.

Dusting is the formation of fine and loose powdered concrete on the hardened concrete by disintegration. This damage occurs due to the presence of excess amount of water in concrete and causes dust at the top surface due to bleeding of water with fine particles like cement or sand from concrete.

And efflorescence is the formation of deposits of salts on the concrete surface. The color of ones generally is white. The presence of soluble salts in the water which is used in making concrete mix is the cause of this problem because when concrete is hardening, soluble salts gets lifted to the top surface by hydrostatic pressure and forming complete drying salt deposits on the surface.

What are causes of damages in concrete structures?

Causes of damages in concrete structures can be due to fire, floods, earthquakes, cyclones and other natural events, marine environments, chemical attack and abrasion of granular materials. Also structural deficiency due to errors in design, loading criteria, unexpected overloading and construction defects can be causes of these.

What are the types of common damages in masonry structures?

Common damages in masonry structures are cracking, spalling, staining, moisture penetration, adhesion failure, cracks due to tree roots, bowing (vertical bulges), sweeping (horizontal bulges), leaning and mortar deterioration.

Cracking occurs due to several causes. The principal causes of this damage are the settlement of foundations that generates shearing stress, excessive loading and deformations due to other effects such as creep, shrinkage and thermal and the interaction within structural and non-structural elements. Bowing occurs because of excessive slenderness wall. Others damages are crushing due to high compressive loads and corrosion of metallic elements or chemical reactions. The cracks develop faster due to poor maintenance.

The cracking in masonry structures damages, usually, the applied finishes, which doesn’t make structural problem but it is an aesthetical one. Cracking in the applied finishes allow the entrance of water into the structure what cause previous damages types.

Spalling is when the brick is weathering and pieces of it are falling. This damage occurs when the masonry is under stress due to moisture penetration.

Staining is a problem on the exterior masonry wall principally, because affects its appearance, caused due to aging, water penetration and the elements.

Moisture penetration is because masonry has a higher affinity to water, then when wall is exposed, it absorbs water and begins losing structural integrity, because due to the pressure in the brick structure, this material begins to crumble gradually.

Adhesion failure is when a wall fails its adhesion between its bricks. The common signs of this failure are the bulging wall, flaky tops and peeling.

Cracks due to tree roots occurs sometimes when roots enter into the masonry structure in search of moisture, then they begin to grow and expand, exerting pressure that cracks open the bricks.

How prevent the damages in concrete and masonry structures?

The prevention of damages in the structures begins with the selection the right materials and follow-up the manufacturer´s instructions, which is the principal way of minimize the damages.

The contractors should keep the observance of building plan in the process of construction, then is very important the communication between the contractor and the architect or engineer of the project in order to get clarification about issues during the build.

The monitoring of the woks in situ from the beginning of the build should be realized for the responsible of quality control, in order to identify any problems and solved as early as possible.ç

After the finishing of edifications, the owners should inspect the building periodically in order to identify possible damages and proceed to reparation.

How systematical actions help to prevent these damages?

The owners can realize many actions to minimize damages in the buildings, such as to paint systematically with waterproofing paint to prevent moisture, repair cracks in walls to prevent entry of water, check joints around windows and doors and electrical and plumbing penetrations and refill its, it is necessary.

This action is called building maintenance, that include activities in order to retain, to restore and to provide a safe, comfortable and perfectly functional system in the building.

There are three type of maintenance. The first is routine maintenance; it is the primary maintenance which needs to protect the building from any king of decay in the one. Principally, routine maintenance includes checking electrical wiring, lubrication of hinges, inspection of emergency utility, garbage cleaning, renewal of plastering, painting walls, painting woodworks, etc.

Some activities need be attended periodically because the materials have limited life, such as painting internal and external surfaces of building since if they are porous and absorbs moisture which causes permanent damage in the walls and ultimately affects the structure seriously and the external painting seals the pores of the plaster and protects the structure. Other activities are growth of small plants may be observed on the wall because they would create cracks in the adjoining portion of the wall and would lead to major trouble in future; plastering on the walls both internal and external and ceiling may, at places, show bulging or cracks; and narrow hair cracks in the walls.

The second type is preventive maintenance; it inspects any kind of damage in the building and retains the building from any kind of damage, also increases the durability of any kind of building structure and improving the quality of construction and makes it more durable and functional. Preventive maintenance includes actions prior to commencement of construction and during the construction, such as soil investigation, collection of information about climatic condition, selection of right material for construction and using those in proper way as per specification and according to I.S. Code, improvement of workmanship by engaging trained workmen.

And the last type is corrective or remedial maintenance. Because of a structure may undergo decay and damage, in spite of taking all possible preventive measures and providing routine maintenance. This maintenance is removal of any decayed or damaged part of the structure or removal of any defect in the structure and to restore the functionality and comfort of the building.

Conclusions

The useful life of a structure is guaranteed from the beginning of its design, to the selection of optimum quality materials, the correct execution of the construction works and its preventive maintenance over time. That is why it is important to know the different types of damage that structures can present and their possible causes to avoid committing them or reduce their incidence. In addition, this article includes the services that our company, Eastern Engineering Group, provides for the repair of structures.

Our Company Eastern Engineering Group supply the following services to repair the buildings:

1.- Inspection for identification of deteriorated elements and potentially unsafe conditions.
2.- Development of Repairs Plans, Details, Repair Procedures indicating Products and Materials, Threshold Inspection Plan.
3.- Assist the Property in the Bidding Process. Provide a preliminary Estimated takeoff of damages to help the Contractors to Estimate Construction Costs. Negotiate bids with selected contractors. Assist the Property in selecting contractors by attending meetings, confirming credentials, and reviewing scope of work, estimates and schedules provided by Contractors.
4.- Inspections for Control of the Repair Process. Provide Threshold Inspector Affidavit, Threshold Inspection Plan,
5.- Provide Final Certification Letters.

Our Company will help bring the structure up to safety standards and pass the Recertification Inspections cycle (25 years, 30 years, 40 years, 50 years…) according with the recent legislation.

Bibliography

De Schutter, G. (2013). Damage to Concrete Structures.
Kovler, K. and Chernov, V. (2009). Types of Damages in Concrete Structures.
Thomaz, E.; Sousa, H.; Roman, H.; Morton, J.; Silva, J. M.; Corrêa, M., Pferffermann, O.; Lourenço, P. B.; Vicente, R. S. and Sousa, R. (2014). Defects in Masonry Walls. Guidance, Prevention and Repair.
Pinconsult Associates Limited. (2022). Defects in Concrete Structure: Causes and Prevention.