Structural Integrity Inspection Checklist
In addition to structural design, one of the responsibilities of a Structural Engineer is overseeing and managing on-site activities related to structural aspects. This ensures that all work carried out on the site aligns with the approved drawings. When working on the consultancy side, specific tasks include regular site inspections, especially during the initial construction phases, spanning from excavation to the casting of the roof slab. Site visits entail inspecting ongoing construction activities, requiring a sound understanding and technical expertise to ensure strict adherence to approved drawings. This is crucial for maintaining safety standards and upholding the overall integrity of the design.
Below are the checklists to be taken into account when inspecting the structural members on-site during construction
Prior to commencing any work, it is crucial to thoroughly verify the specified formation level or excavation depth. This measurement should align with the gate level set by the relevant authority, such as the municipality or city engineer. It is essential to adhere to the soil recommendation report, specifically in terms of proper placement and compaction. The subgrade layer, as advised in the soil recommendation, must be meticulously followed on-site. The following excerpt outlines the soil recommendations to be observed during the excavation process.
1. Excavation
Prior to commencing any work, it is crucial to thoroughly verify the specified formation level or excavation depth. This measurement should align with the gate level set by the relevant authority, such as the municipality or city engineer. It is essential to adhere to the soil recommendation report, specifically in terms of proper placement and compaction. The subgrade layer, as advised in the soil recommendation, must be meticulously followed on-site. The following excerpt outlines the soil recommendations to be observed during the excavation process. In addition to following the recommendations outlined in the soil investigation report, the structural engineer should conduct a comprehensive examination of soil depressions caused by the sump pit or an elevator/lift pit. This is done to verify that the angles or bends of the steel reinforcement are accurately adhered to during the installation of rebar.
2. Footings/Foundations
After the completion of excavation works in accordance with specifications, the contractor is authorized to commence rebar installation for the footing/foundation. Subsequently, they request the consultant to inspect their work on-site. As a consultant, the following checklists should be considered during the site inspection, assuming that the concrete blinding has already undergone inspection at this stage.
Steel Reinforcements
The initial step is to verify whether the steel reinforcement implemented or supplied aligns with the site conditions and corresponds to the specifications outlined in the footing/foundation schedule. In the case of a raft foundation, it is essential that the primary mesh reinforcements, along with the specified top and bottom extras, are installed in accordance with the approved foundation layout.
Lap Splicing
It is imperative to ensure that the lap splice has sufficient development length and should not be overlooked to achieve 100% continuity of rebars. The lap splicing can be verified in accordance with the approved drawing, typically specified in the general notes. Alternatively, confirmation can be made using the design code and standards.
Concrete Cover to Reinforcements
The nominal concrete cover to reinforcements in foundations cast against or permanently in contact with the soil or substructure must be meticulously examined according to the applicable code and standards. This cover is typically thicker than the concrete cover for reinforcements in superstructures, usually ranging from 50mm to 75mm. This thickness is essential to protect the steel reinforcement from potential corrosion and sulfate attacks present in the soil. More detailed requirements for concrete cover, as per ACI318M, are specified in the latter part of this article.
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3. Tie Beams/Grade Slabs
Similar to any other structural element, the primary focus during a tie beam site inspection should be on the steel reinforcement. Thoroughly check the stirrups/link reinforcements and the quantity of top and bottom bars laid on-site against the tie-beam schedule, ensuring they align accurately. The concrete cover must comply with the specified code and standards, typically ranging from 50mm to 75mm, given that tie beams are sub-structures cast permanently with the soil/earth. Proper alignment is also a crucial consideration during the site inspection.
For grade slabs, verify the reinforcement against the main mesh specified in the approved drawing. Ensure that spacers are provided to maintain the required concrete cover for the grade slab’s reinforcements.
4. Columns/Shear Walls/Retaining Walls
The key aspect to examine across columns, shear walls, and retaining walls during a site inspection is their vertical alignment. In addition to verifying the required concrete cover, the quantity of steel reinforcement, and the spacing of stirrups/links against the structural schedule, it is crucial to consider the vertical alignment of these elements before closing the formworks. During the site inspection, particular attention should be given to starter bars and joint details, especially in cases where columns/walls exhibit eccentricities. Ensuring the continuity of columns from lower to upper floors is vital for maintaining verticality.
5. Inspecting Slabs and Beams
During a site inspection, it is crucial to focus on the suspended slabs and beams by comprehending the bar bending details. Ensure precision in identifying the specific slab or beam under examination. Verify the quantity of steel reinforcements on both the top and bottom, including any additional bars. As a consultant, it is essential to illustrate the correct placement of each reinforcement in accordance with the structural schedule.
6. Slab Openings/Parapet Walls
The presence of openings in slabs is a common occurrence in construction, serving MEP requirements for air-conditioning ducts, ventilators, or architectural design. Despite its seemingly minor nature, it plays a crucial role in the structural stability of the slab and should be treated seriously during site inspections. Thoroughly checking the main reinforcements of slab openings against approved drawings is essential. If there are doubts about the required number of bars or their placement, as a consultant, it is within your right to question and insist on what you deem acceptable. If details about additional bars are unavailable, consulting the relevant building code or referring to previous articles is recommended.
Similarly, like any standard wall, parapet walls should undergo meticulous inspection to ensure compliance with vertical and horizontal spacing outlined in the reinforcement schedule, rebar bends, development length, concrete covers, and other specifications.
Nevertheless, adhering to the above checklists also involves maintaining good housekeeping practices before concrete casting. Ensure that laitance is removed, and there is no loose concrete, tie-wires, or other debris scattered in the designated area. Prioritizing overall safety should always be the top consideration.
FAQs
Overseeing on-site activities ensures that all construction work aligns with approved drawings, maintaining structural integrity and safety standards.
On-site inspections include tasks such as verifying excavation depths, inspecting rebar installations, and ensuring compliance with approved structural plans.
Verifying excavation depths ensures alignment with authority-set gate levels and adherence to soil recommendation reports, critical for the proper placement and compaction of subgrade layers.
The engineer conducts a comprehensive examination of soil depressions caused by pits to ensure accurate adherence to steel reinforcement angles and bends during installation.
Key considerations include verifying steel reinforcements, ensuring lap splicing meets development length requirements, and meticulously examining concrete cover thickness based on applicable codes and standards.
For tie beams, attention should be on stirrups/link reinforcements, steel quantity, and concrete cover. Grade slabs require verification of reinforcement against drawings and proper placement of spacers to maintain concrete cover.
Focus on vertical alignment, required concrete cover, steel quantity, stirrup/link spacing, and details such as starter bars and joints. Ensuring continuity in columns is crucial for maintaining verticality.
Inspection involves understanding bar bending details, verifying steel quantity, and ensuring proper placement of reinforcements according to the structural schedule, contributing to overall structural stability.
Slab openings impact structural stability, and thorough inspection ensures compliance with approved drawings. Parapet walls are inspected for adherence to reinforcement schedules, bends, development length, and safety measures.
Good housekeeping practices, such as removing laitance and debris before concrete casting, contribute to overall safety and ensure a clean and safe construction environment.
Conclusion
In the realm of construction, safeguarding structural integrity demands meticulous oversight. This Structural Integrity Inspection Checklist underscores the critical role of a Structural Engineer in ensuring that on-site activities align seamlessly with approved drawings. From excavation to the final casting, each phase requires careful scrutiny. The checklist provides a systematic guide for inspecting crucial elements like foundations, tie beams, columns, slabs, and more. Beyond technical specifications, it emphasizes the importance of maintaining a clean, hazard-free environment. By adhering to these checklists, professionals contribute not only to structural soundness but also to the overarching safety and success of construction endeavors.