Bridge Inspection Procedure:
Adequacy of bridge inspection relies upon the exact recording of the actual data. When the observation is made, data will be recorded. Notwithstanding recording defects or damages, their nonattendance will likewise be recorded. On the off chance that any recently noted defects have been rectified, the equivalent will be recorded. The inspection will follow a pre-decided example to guarantee that no component is ignored.
Bridge Inspection Sequence:
Following the pattern of the inspection may be adopted:
- Pre-stressing Material (for prestressed bridge)
- Wearing Coat
- Concrete Crash Barrier/Railing
- Expansion Joints
- Drainage Spout and Down Take Pipe
Details of Bridge Inspection:
The details of the bridge inspection of various items are described below.
- The reviewing officials will examine the waterway under the bridge during each monsoon and the floods and will get ready report considering the followings:
- The maximum flood level saw during the year will be marked on the piers and will be compared with the design flood level.
- The maximum watched afflux will be recorded from D/S and U/S watermarks on piers.
- The maximum scour level will be recorded.
- If there is any strange difference in flow pattern
- Any impediment in the waterway like island arrangement, vegetation development and so on will be recorded.
- Erosion of bank, pitching if any will be noted during monsoon.
- To record the foundation settlement survey points will be marked at every pier so that these will be accessible from survey stations at the reasonable interim.
- For right measurement, such reading will be taken by the auto level when vehicular traffic is negligible. These reading will be crosscheck with the records evaluating if any settlement has occurred.
Cracks, Impact Damage, Honeycomb, Spalling of concrete and Efflorescence:
- Condition of RCC abutments, piers, Pier cap, pedestal and so on will be checked for the damages because of impact, cracks, honeycomb surface, spalling.
- The deterioration of concrete will be checked especially at construction joints and pier cap area.
- Damage because of impact from boats, vessels, gliding logs or trees and so forth will be checked consistently, and the fundamental measure will be taken to maintain a strategic distance from such impact.
- Everything will be recorded and assessed to decide its impact on the structure and work required to reestablish the loss of structural integrity. The in-situ quality of concrete will be estimated by Schmidt Hammer Test and Ultrasonic test for deciding the structural capacity of the area.
Exposed Reinforcement and Rust Staining:
- During the bridge substructure inspection, any uncovered reinforcement and its condition, for example, corrosion, breaking and so forth will be recorded and cause behind it will be brought up.
- Other than the abovementioned, any impression of rust in the concrete surface because of improper cover which will be estimated by Cover Meter, and for corrosion will be evaluated by Half Cell Potential Meter.
Wet Spots and Vegetation Growth:
- The wet spot and vegetation growth of substructure will be recorded for each span, and reasons for leakage will likewise be identified and informed to a higher authority for consideration.
- At monsoon leakage of water from the expansion joint will be checked as concrete surface and reinforcement are influenced because of leakage of water.
Bridge Superstructure Inspection:
- Basically, the deflection of the superstructure for full traffic load condition will be visually inspected if there is any variation. Permanent survey points will be marked on the median side crash barrier and reviewed periodically to find the deflection of the superstructure with live load and without live load condition.
- Excessive deflection/vibration of the bridge deck influences the safe movement of traffic as well as design velocity. On the off chance that any abnormal occasion happens, this will be estimated by instruments with full traffic condition and without traffic condition, and these will be checked with design value as referenced in design.
Cracks, porous area, Spalling of concrete and Efflorescence:
- The concrete girder, deck, diaphragms, anchorage location, will be checked for cracking, leaching, scaling, potholing, spalling and other proof of disintegration.
- The top surface of the wearing coat will be observed completely for analyzing the chance of the defects in the deck section. The region where deck disintegrating is suspected may require expulsion of surfacing for expand inspection.
- The inspection will likewise be made for deflections of the cantilever projecting slab from the web of the box-girder.
- Hairline and fine cracks are hard to identify on a dry concrete surface, so the inspection method ought to incorporate saturating the concrete surface with water.
Exposed Reinforcement and Rust Staining:
- During the bridge superstructure inspection, any uncovered reinforcement and its condition, for example, corrosion, breaking and so forth will be recorded and cause behind it will be brought up.
- Rust in the concrete surface happens because of inappropriate cover, which will be assessed by Cover Meter, and Half Cell Potential meter will determine corrosion.
Deficiencies for segmental construction:
- Joints between segments for the segmental bridge are compared to weak and may distress due to frequent fluctuation of stress. Cracks, spalling of concrete, broken edges, wet spots, exposed reinforcement, gaps etc. may occur in these joints.
- During the inspection, the above defects will be appropriately recorded for inside and outside of the box. It helps to assess the cause of defects.
- There might be spalling of concrete adjacent to a match cast joint.
- Repairs to keys made during construction, for example, epoxy mortar patches, which have relaxed or spalled.
- Water leaking through the deck into the interior of the box girder. Dampness or formation of lime deposits or coatings on the underside of the deck is an indication of spillage.
- Perhaps present cracked joints, for example, cracking of the cast-in-place closer joints between superstructure segments of the bridge unit. As non-shrink concrete was utilized for these joints, they ought to likewise be checked for the avoidance of water infiltration.
Wet Spots and Vegetation Growth:
The wet spot and any vegetation growth of bridge superstructure will be recorded for each span, and reasons for leakage will likewise be identified and notified to the higher authority for their consideration. Concrete surface and reinforcement are adversely affected because of leakage of water.
Condition of Pre-stressing Material:
- Each pre-stressing steel will be checked for its condition, voids in the grout, corrosion in the stand, and force in strand during live load and without live load.
- The condition of each cable will intermittently be checked and surveyed by the particular organization as test premise.
- Voids in grout, corrosion, excessive loss of force in cable and causes behind it will likewise be ascertained. The Impact-Echo method is applied to recognize the nature of grouts within the ducts.
- Geo-radar is an alone reasonable method for the confirmation of the location of internal tendons within deck/web/bottom part of the box. Vibration testing is a proficient strategy used to determine the measure of force existing in outside tendons.
- Chances of corrosion will be checked by Half Cell Potential meter.
- Besides the abovementioned, cracks on HDPE pipe, cracks in sealing compound, condition of grout cap and wellbeing of joints of sheathing for outer cables will visually be checked, and any defects will be informed to the higher authority.
- Anchorages without grout caps will be checked for slip and distortion of anchorage.
- Cracks in anchor cone and surrounding concrete surface will be checked.
- Corrosion in anchorage must be checked and recorded.
- The actual time of distress will likewise be recorded to find out the reason for distress and its remedial measure.
- On the off chance that grout caps are not given over the anchorage, condition of grout caps, cracks/damage in surrounding concrete surface will be checked just, and these will be tended to for the healing measure.
Bearings will be inspected once in a year during temperature boundaries and likewise after the events of unordinary earthquakes or entry of excessive traffic loads for examining any displacement in position or change in utilitarian behaviour and cleanliness of parts. The following components and activities will be inspected to monitor and upkeep:
- Measurement of movement
- Measurement of dimensions
- Evidence of the locked-in condition
- Evidence of corrosion
- Coordination of adjacent bridge structure
The elastomeric bearings shall be inspected to ascertain the following:
- The deterioration like oxidation, creep, lead, flattening, bulging, splitting, etc. which results in the formation of cracks, spelling, etc. of the pads shall be inspected.
- The cleanliness of bearing and its surroundings, mainly to keep away from contact with oil, petroleum, and so forth will be checked.
- While inspecting a bearing pad, the inspector ought to likewise make note of any spalling of concrete or mortar in the proximity of the bearing.
- The condition of bituminous wearing course will be checked once every month. The inspecting officer will report the following:
- Presence of any potholes, cracks, revealing, depressions and disintegration of road surfacing ought to be checked and recorded.
- Evaluation of riding quality.
- Reviewing the actual thickness periodically against the designed thickness.
Concrete Crash Barrier/Railing:
- The Concrete Crash Barrier will be inspected for damages, cracks, spalling of concrete and deterioration.
- Any damage to the crash barrier resulting from hitting of vehicles is to be recorded.
- Exposed reinforcement because of damage or spalling of the concrete ought to be checked. Often rust strains on the concrete are indicative of corrosive activity on the steel inside the concrete and will be noted.
- During the inspection operation, the gap between adjacent concrete crash barriers at expansion joint location will be measured to monitor the movement of the expansion joint and the end rotational alignment associated at the location.
The inspection engineer ought to be familiar with the pertinent drawings for its components, capacities and fixing details and so on, so any watched deviation can be thought about in like manner. The inspecting Engineer will cover the following points:
- Whether the joints are functioning correctly and whether the transverse grooves stare clean or filled up with debris.
- Condition of strip seal, check for splitting, cracking, oxidation, etc.
- The rattling of expansion joint under traffic condition should be checked.
- Condition of mild steel angles etc. will be checked for any corrosion.
- Sliding Plates will be checked at the location of crash Barriers joints.
Drainage Spout and Down Take Pipe:
- The drainage spouts will be checked for damage.
- The projection of the drainage spouts will be checked to understand that the basic parts are not affected.
- The drainage spouts will be cleaned once, in a month during monsoon, more frequently on water stagnation.
Others Checks for Bridge Inspection:
The dust will be cleaned according to standard for the maintenance of appropriate camber and riding surface. The dust and garbage/plastics and so on in median will be cleaned inconsistently, particularly in the monsoon. The cleaning of dust will helps appropriate drainage of water. Thus, deposition of dust over wearing coat particularly at sides will be recorded. Erosion at inlet/outlet of pipe will be checked regularly, especially in monsoon.