Structural Assessment and Structural Investigation – Structural Repairs, Strengthening, Protection and Restoration for Malaysia Buildings

Identifying The Causes Of Crack Patterns: Cracks Mapping & Visual Inspection

superadmin — Tue, 13 Dec 2022 08:15:49 +0000

It is essential to determine the type and cause of the cracks developed in concrete structure by cracks mapping or visual inspection. Additionally, it would take less time and effort to determine the cause of cracks initiation.

What are the types of crack patterns and their causes?

Cracks due to earthquake – Seismic forces can be seen as cracks in both beams and columns.
Cracks due to bending and shear forces – Vertical cracks in the centre of a beam caused by bending moments, and inclined or diagonal cracks close to the beam supports caused by shear stresses.
Cracks due to column settlement – Cracks caused by differential column settling can be found at the top of the settled column and on the top side of the slab next to the settled column.
Cracks due to ground condition changes – Low-temperature cracks are depicted in (a) above, while dryness-related crack maps are given in (b).
Cracks due to concrete settling – The cracks that run horizontally reveals concrete settling is the reason for it.
Cracks due to sinking of timbering – Such types of cracks in reinforced concrete elements are the result of improper formwork.
Cracks due to bowing of formwork – Cracks along the length of the formwork that have significantly bent or deflected.
Map of cracks caused by abnormal set of cement – A pattern of cracks has formed as a result of the unusual cement setting.
Cracks due to insufficient reinforcements – Cracks that have formed as a result of insufficient reinforcing ratio. The beam’s span was where the cracks started to appear.
Cracks due to atmospheric conditions – Because of fluctuations in the climatic conditions, such as high temperatures or wetness, a pattern of cracks appeared in the structural wall.
Crack pattern of fire effect – Reinforced concrete columns and beams that have developed cracks as a result of exposure to fire.
Cracks due to non-uniformity of admixture – The cracks found to be caused by non-uniformity of admixture in concrete.
Cracks due to steel rusting – Steel bar rusting, which is brought on by carbonation and chloride ions, is a common reason for structural damage.
Cracks due to concrete sinking – Around the steel bars is where the cracks first appeared and then grew.
Cracks due to loss of workability – Resulted from mixing concrete for too long or too long time of concrete transportation.
Cracks due to unsuitable process at construction joint

Key Takeaways

It is important that we should learn and identify the crack patterns accordingly. The importance of identifying the crack patterns includes:

Safety – It is arguably the most vital factor to consider when identifying about concrete cracks. Cracks in concrete can occasionally be a sign of a building’s structural stability. As a result, a crack in the concrete could indicate the impending catastrophic failure of a key component of the building’s structure, such as a concrete post, the perimeter foundation, or the basement wall.
Reduce repair cost – Property owners will have a better notion of what mitigating measures to use, where to use them, and how to employ them if they are aware of the fundamentals of concrete cracks, their causes, and the various repair choices. A shrinking crack is an illustration of this. Shrinkage cracks may appear exceedingly foreboding and worrisome to the untrained eye. If the property owners don’t take reasonable precautions, they may find up spending more than necessary to address what is typically a cosmetic issue.
Evaluate of urgency of repair – Understanding the fundamentals of concrete cracks will help property owners determine how urgently repairs must be made. For instance, cracks caused by one-time, uniform foundation settlement may not need repairs as urgently as cracks which are still an active problem. Knowing about concrete cracks can at the very least help property owners understand how important it is to seek professional guidance when faced with various forms of concrete cracks.

In order to create a usable image of why and how to address these cracks , cracks on a plan are mapped out, including joint positions, joint types, and any places of constraint which is known as cracks mapping.

Dilapidations Surveys , commonly referred to as Condition Reports, are thorough examinations done to document the state of an existing concrete slab. Dilapidation studies typically examine surface deterioration, excessive staining and pollution, as well as wear and tear on the concrete slab.

Structural Repairs (M) Sdn Bhd offers a variety of dilapidation surveys, from surface condition to in-depth structural inspections and analysis. We have more than 30 years of experience in this industry.

We do provide free consultation! Please do not hesitate to contact us if you see cracks on your building structures!

Our team will be happy and glad to assist you.

Kindly visit to our website at https://structuralrepairs.com.my/ or contact us at Tel: +603-91731728/29 Whatsapp: +60 12-334 9113

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Structural Assessment: Its Importance & Procedures

superadmin — Fri, 09 Dec 2022 03:03:47 +0000

The subject of structural integrity and structural assessment has gained popularity. Tenants also want the reassurance that the structure they are renting is safe for those who use it, as do building owners and operators. Many readers, however, might not fully comprehend what a structural assessment involves or why they are so crucial. Let’s investigate those topics in more detail and look at the information that can be useful if you want to perform a structural assessment soon.

What is structural assessment?

Engineers can verify the accuracy, structural soundness, and strength of structures and their components using a structural assessment technique. A structural assessment is performed to determine the future usage and compliance with the current building codes as well as to examine the current condition of the structures.

In what circumstances structural assessment is needed?

A building needs to undergo routine inspections and maintenance in order to maintain a safe and healthy atmosphere and make sure that all of its parts are functioning properly. Otherwise, minor problems that are ignored run the risk of becoming expensive or risky to repair. Several circumstances, including the following, may call for a structural assessment: –

When a building has been purchased or sold.
When new machinery is installed.
When assessing the structural capacity and viability of any building additions or renovations.
When a building’s usage or occupancy changes.
When changes are found that could be a sign of a structural problem.
When there is change in structural loading.

What are the steps for structural assessment?

These steps should be taken into account while evaluating the building’s structural condition:

Site Background
When evaluating the current condition of the existing building, it is crucial to understand the site history. This is the first step in the process. From this point, we may start to learn more about the structure that is being evaluated. Before we begin the evaluation, there are a few things we need to know, including the building’s age or construction date, its change in occupancy, and any renovation work that has been done. These variables will already provide us a sense as to what our strategy will be and how we will be able to use this data in our evaluation.
Actual Site Inspection and Visit
To do a preliminary evaluation of the building and ascertain the potential severity of the damages and faults, a visual site inspection is required. The Engineers should actually visit the site to conduct a visual evaluation and obtain information about the building’s condition. Physical defects including cracks, corrosion on the reinforcement, obvious beam deflections, and other visible defects should be photographed and documented.In order to detect any potential structural defects, such as cracks, excessive movements, bowing, deflections, or differential settlements, structural evaluation process involves visual observations of structural members like columns, beams, joists, load-bearing walls, slabs, roof decking, foundations, and connections. The following are typical inspection findings that can be found in concrete during site inspections and observations: –
- Cold joints
- Honeycombed concrete
- Hairline cracks in slabs and slab soffits
- Exposed steel reinforcement due to insufficient concrete cover
- Column misalignment due to bad formworks during casting
Collecting Structural Samples for Lab Testing
Concrete samples or specimens should be gathered on the spot and transported to the lab for additional analysis. This is done to determine the density and compressive strength of the current structural members and to further validate the necessary information and data. Non-destructive testing ought to be carried out in most cases. It is advisable to do site testing, which may involve: –
- Covermeter Survey – It was carried out using a Protovale Covermeter and in accordance with the recommendation as specified in BS 1881:Part 204. The test uses the idea of the magnetic field signal produced by the equipment probe to identify embedded ferromagnetic steel reinforcing bar (herein referred to as rebar). When the device records the strongest pitched signal, the rebar is identified, and the concrete cover is then immediately read from the metre (after pre-setting the rebar size). The spacing of the main and secondary/link rebars was also calculated by finding the nearby rebars. In this exercise, covermeter test was performed at the RC member covering area not less than 500mm x 500mm at each test location. Concrete cover measurement was then obtained from the rebar nearest to the concrete surface.
- Carbonation Test – The depth of carbonation of the concrete was determined using a phenolphthalein indicator solution (colourless) in accordance with the BRE IP/6. The indicator solution was either sprayed onto the freshly cut surface of the extracted cores or the coring/hacking holes in the element. The depth of concrete, onto which the surface remains colourless after the solution was sprayed, is measured as the depth of carbonation Carbonation is a process whereby carbon dioxide and moisture from the ambient environment react with the alkaline constituent of cement paste to form calcium carbonate, thus could reduce the alkalinity of the cement paste. This reaction destroys the concrete passivation effect that protects the reinforcement. In this exercise the carbonation test was performed on the freshly cut core.
- Rebound Hammer – Rebound Hammer test was carried out using a Schmidt Rebound Hammer in accordance with the recommendation as specified in BS 1881:Part 202. In normal exercise, 12 nos rebound number readings were obtained at an interval of 25mm square grids over an area of 100mm x 75mm area at each test location.
- Resistivity Measurement – Concrete resistivity test was performed using a Wenner-Proceq Model resistivity meter. This test measure the electrical resistivity of reinforced concrete which influences the corrosion rate of the rebar. Corrosion of steel is an eletrochemical process which generates movement of ionic current and can dissolve metals. The lower the electrical resistance, the more readily the corrosion current flows through the concrete and the greater is the corrosion rate for the rebar. The classification of the rebar corrosion rate at each test location can be assessed by comparing the measured potentials with the guideline given in John P. Broomfield “Corrosion of Steel In Concrete” 1997 publication and shown in table below.
- Extraction of Concrete Strength Test – Concrete core samples of either 75mm or 100mm diameters were extracted from selected RC members using a coring machine with water cooled diamond tip core cutter. Before coring, a covermeter survey was first carried out to locate the reinforcement. The concrete cores were sent to the laboratory for compressive strength.
- Core Compressive Strength Test – The concrete core samples were tested in compression in accordance with BS 1881 : Pt 120 : 1983 to determine the estimated in-situ cube strength (EICS) of the concrete. In addition, visual examination and density measurements were also performed on these samples.
- Ultrasonic Pulse Velocity Test – The test was conducted using a “PUNDIT” tester in accordance with BS 1881 : Part 203 : 1986 employing the direct method.
In this exercise, one (01) no UPV test was performed at each selected RC member. The test result obtained was then qualitatively analysed to assess uniformity of the concrete of the RC members.
Damages and Defect Markups
A summary of the defects detected during the site inspection should be prepared by the engineer. It is important to accurately record on the plans any faults and defects discovered during the visual assessment. Each plan should provide a detailed description of the types of faults and their locations. This makes it simple to find and inspect the defects for future use. The engineer will create a thorough plan that takes into account all architectural and structural factors.
Analyzing and Evaluating Test Results
The next duty for the engineer participating in the evaluation of the structural integrity of the existing building is to synthesise all the results and findings based on the physical and mechanical properties of concrete and as a result of the data and laboratory tests mentioned above. He or she should list and clearly delineate these facts before drawing a judgement on the general safety of the building. At this point, the concrete’s quality is known, the area’s actual concrete coverage has been determined, and perhaps most significantly, the concrete’s actual compressive strength f’c has been determined.
Conclusion
After the interpretation and conclusion are provided, a recommendation is also necessary. If structural strengthening is necessary for the affected structural members, the structural engineer will either suggest it or make the final decision. The defects that are physically visible should be repaired if necessary. Therefore, in the event of low concrete compressive strength results, a structural redesign and design of the building utilising the real design data results acquired from the laboratory testing should be taken into consideration. In order to increase the strength of the existing structures, structural retrofitting and strengthening are a necessity.
Remedial Action
As recommended by the engineer, structural strengthening may be necessary. Planning remedial work is necessary to ensure the building is structurally sound and safe. It is important to think about the type of repair that is necessary as well as the process for carrying it out. According to the engineer’s findings and recommendations, structural improvement, jacketing, and retrofitting may be suggested. For some concrete/structural strengthening ideas, read this article at https://structuralrepairs.com.my/carbon-fibre-strengthening-the-advantages-of-carbon-fibre-for-existing-structures/For some structural strengthening projects which Structural Repairs (M) Sdn Bhd had completed previously, read the project references at https://structuralrepairs.com.my/projects/structural-repair-strengthening/

Resistivity (kWcm)	Classification
> 20	Low corrosion rate
10 to 20	Low to moderate corrosion rate
5 to 10	High corrosion rate
< 5	Very high corrosion rate

Key Takeaways

The building’s structural assessment is obviously a highly important operation that must be carried out correctly. Therefore, it’s crucial that you work with a civil engineering firm that employs structural engineers with ample knowledge and the ability to manage the structural evaluation process effectively. It is crucial that the business has the necessary tools and amenities to do the proper study of the structure.

We, Structural Repairs (M) Sdn Bhd have more than 30 years of experience in this industry. We provide the structural assessment services as follows: –
Structural Assessment Services

Condition Assessment/ Forensic Evaluation of Existing Structure
Preliminary assessment
Non-destructive testing
Preparation of as-built drawings
Budgetary cost estimation

Repair, Protection and Strengthening Work

Setting up quality norms and procedures
Project monitoring
On-site real-life load tests

Please do not hesitate to contact us if you require more information. Our team will be happy and glad to assist you.
Kindly visit to our website at https://structuralrepairs.com.my/ or contact us at Tel: +603-91731728/29 Whatsapp: +60 12-334 9113

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Maintenance and Inspection of Railway Tracks in Malaysia

superadmin — Wed, 16 Jun 2021 06:07:39 +0000

The ever-increasing problems faced around the world have the demands that transportation need to be improved as an effective and efficient communication means. It is considered as a necessity especially when rapid development and economic growth of a country is the agenda. In Malaysia, the railway network has evolved tremendously since its inception in the early 19th century. It has grown proportionally with the national development. Railway network does not only mean for rural transportation, but it also considered as a solution to urban congestion challenges. Currently, urban rail transit is the most popular means of urban transportation system especially as big cities such as Kuala Lumpur. To keep the tracks open and functioning, periodic inspections and maintenance is required. Tracks used in revenue service should be inspected at least once a week. An interval of at least 3 but not more than 11 days must elapse between inspections. Transit systems that operate discrete track segment at greater than 90km/hr requires twice weekly inspection. Common maintenance issues on railway tracks includes:

1. Insulated joints and associated signal system circuitry prevent trains from hitting each other shall be check regularly.
2. Rail corrugations which are a form of surface track rail and requires grinding to remove the rail defects.
3. Repair of Switches & Frogs. Periodic measurements will be made to facilitate in predicting when the frog or switch point will be worn out.
4. Emergency repairs whereby the train track buckles which could cause derailment.

For more info, please contact Helpdesk.

We are specializing in Waterproofing, Concrete Repair, Structural Strengthening and Building Conservation for commercial and residential projects.

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Extending the Lifespan of a Building

superadmin — Thu, 20 May 2021 02:51:26 +0000

The lifespan of a typical concrete building usually ranges from 75 years to 100 years or more. Buildings deteriorates over time due to normal wear and tear. And regular maintenance can improve and lengthen its service life. Property/facility managers should prepare a significant funds to be invested into the maintenance and repair works of the building as it approaches it’s 30-year-old mark. Old waterproofing membrane needs to be renewed and replaces, structural issues need to be address, facades need to be repair if required etc.

We at Structural Repairs understands the importance of maintenance of a building in relation to it’s life span and is able to carry out the maintenance/repair works with the highest quality.
For more info, please contact Helpdesk.

We are specializing in Waterproofing, Concrete Repair, Structural Strengthening and Building Conservation for commercial and residential projects.

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