The German standard for structural inspection of bridges using RI-EBW-PRÜF damage rating and ASB-ING classification.

The Hauptprüfung (H) — Main Inspection — is the most comprehensive assessment and the foundation of Germany's bridge maintenance regime. It requires hand-close (handnah) examination of all structural components and is mandatory every six years, split into H1 and H2 cycles. For bridges, this means the inspector must physically reach the superstructure underside, bearings, abutments, pier shafts, expansion joints, drainage outlets, and the bridge deck — using under-bridge inspection units (Untersichtgeräte), aerial lifts, boats, scaffolding, or drones where direct access is impractical. Every visible and accessible component is examined, and all defects are rated using the S-V-D system. The Main Inspection is the baseline for the structure's Condition Grade.

The Einfache Prüfung (E) — Simple Inspection — is performed three years after each Main Inspection, providing a mid-cycle visual assessment. It focuses on changes since the last Main Inspection: new cracks, progression of existing defects, bearing displacement, joint seal deterioration, and drainage blockages. While less intensive than the Main Inspection, it still requires the inspector to evaluate each component group and update defect records. Defects flagged with the EP-Vormerkung (Simple Inspection Flag) during the previous Main Inspection receive special attention. The Sonderprüfung (S) — Special Inspection — is triggered by specific events such as floods, vehicle impacts, overloading, or earthquakes. It can be ordered at any time and focuses on the damage caused by the triggering event. Additionally, DIN 1076 defines the Besichtigung (B) — a visual check that serves as a quick-status review between formal inspections.

In the digital form, the inspector selects the Prüfungsart (Inspection Type) as the first field — choosing between Hauptprüfung (H1), Hauptprüfung (H2), Einfache Prüfung (E), Sonderprüfung (S), or Besichtigung (B) — which sets the expected scope for the entire inspection. A Hauptprüfung triggers the full defect logging workflow with mandatory S-V-D ratings for every finding, while a Besichtigung may only require a general status note. The Besichtigungsgeräte (Access Equipment) multi-select field documents what tools were used — aerial lift, under-bridge unit, boat, scaffolding, ladder, or drone — providing proof that hand-close inspection was achieved where required.

Inspection standards are maintained by the Federal Highway Research Institute (BASt), which provides training programs and inspection guidelines.

Standsicherheit (S) — Stability — measures how the defect affects the bridge's structural load-bearing capacity. A crack in a prestressed concrete main girder receives a far higher S-rating than the same crack type in a non-structural cap, because it directly threatens the primary load path. Corrosion of bearing plates or anchor bolts scores high on S because bearings transfer the entire superstructure load to the substructure. An S-rating of 4 means stability is critically impaired or lost — the bridge can no longer safely carry its design loads and immediate propping, load restrictions, or closure is required. An S-rating of 0 means the defect has no impact on structural capacity whatsoever.

Verkehrssicherheit (V) — Traffic Safety — evaluates whether the defect poses a risk to road users, pedestrians, cyclists, or workers on or under the bridge. For bridges, this axis is critical for railings, pavement condition, expansion joint ride quality, cap stones, and any overhead hazard from spalling concrete. A pothole at an expansion joint that could cause a cyclist to fall scores high on V even if the bridge structure is sound. A V-rating of 4 means safety is not given — the structure must be closed to traffic immediately. Dauerhaftigkeit (D) — Durability — captures the defect's effect on the bridge's long-term service life. Efflorescence on the superstructure underside, dampness penetration through the waterproofing membrane, and early-stage corrosion of reinforcement may not threaten stability today, but they accelerate deterioration and shorten the structure's remaining useful life. A key rule in practice: D is almost always greater than or equal to S, because any defect that impairs stability also impairs durability — but not every durability issue threatens stability.

The three axes are rated independently for each defect. A single crack in the superstructure might receive S:2, V:0, D:3 — it slightly affects stability, poses no traffic safety risk (located on the underside, not accessible to users), but significantly impacts durability because water can penetrate and corrode reinforcement. This three-dimensional profile is what drives the algorithmic Condition Grade calculation: the system takes the maximum rating across all defects for each axis, factors in the extent (Ausbreitung) of each defect — whether it is spot-local (punktuell), widespread (flächig), or linear (linienförmig) — and computes a Zustandsnote that reflects the worst finding across all three dimensions.

The same S-V-D methodology is also applied in the DIN 1076 retaining wall inspection. Similar multi-dimensional rating approaches are found in the NEN 2767 condition assessment, which uses severity, intensity, and extent as three dimensions of defect assessment.

Bridges are decomposed into nine component groups per ASB-ING — significantly more than retaining walls, reflecting the complexity of bridge structures. The Überbau (Superstructure) encompasses the main load-carrying elements: girders, slabs, arches, or trusses that span between supports. Defects here — particularly cracks in prestressed concrete or fatigue cracks in steel — receive the highest Stability attention because they directly affect the primary load path. The Unterbau (Substructure) covers piers, abutments, and wing walls that transfer superstructure loads to the foundations. The Gründung (Foundation) includes pile caps, spread footings, and deep foundations — often partially submerged or buried, requiring boats or excavation for full inspection.

The Lager (Bearings) are the mechanical connection between superstructure and substructure, transferring loads while accommodating thermal movement, rotation, and deformation. Seized, corroded, or displaced bearings are among the most critical defects because they can introduce unintended forces into the structure. The Fahrbahnübergänge (Expansion Joints) accommodate deck movement at abutments and midspan hinges — damaged joints allow water infiltration to bearings and substructure below, making them a leading indicator of future durability problems. The Kappen (Caps/Sidewalks) are the reinforced concrete edge beams that carry railings, barriers, and pedestrian walkways. The Beläge (Pavements/Coatings) include the wearing surface and waterproofing membrane that protects the structural deck. The Geländer (Railings/Barriers) are critical for traffic safety — any loosening, deformation, or corrosion directly affects the V-axis rating. Finally, the Entwässerung (Drainage) covers scuppers, pipes, and channels that remove water from the bridge deck and prevent it from reaching structural elements.

The damage catalog defined by RI-EBW-PRÜF provides standardized defect types across all material classes. Riss (Crack) is the most common finding, with distinct implications depending on whether it appears in reinforced concrete, prestressed concrete, steel, or masonry. Abplatzung (Spalling) indicates concrete cover has broken away, potentially exposing and accelerating corrosion of reinforcement. Kiesnest (Honeycombing) reveals poor concrete compaction during construction. Korrosion (Corrosion) affects steel components, bearings, and exposed reinforcement — scoring high on both S and D axes. Ausblühung (Efflorescence) signals water migration through concrete, while Feuchtigkeit (Dampness) indicates waterproofing membrane failure. Hohlstelle (Void/Delamination) is detected by hammer-tapping and indicates internal concrete degradation. Bewuchs (Vegetation) in joints, drainage, or masonry can mask underlying defects. In the form, the inspector selects the Bauteilgruppe (Component Group), then the Schadensart (Damage Type), locates the defect using the free-text Bauteil/Ort field, and documents it with mandatory photographs.

For further information on the SIB-Bauwerke database system, refer to the Federal Highway Research Institute (BASt), which maintains the system on behalf of the federal government.

The Zustandsnote is not a simple average of defect ratings. The SIB-Bauwerke system calculates it algorithmically by taking the maximum S, V, and D ratings across all logged defects, factoring in the extent classification (spot, area, or linear) of each defect. A single S:4 defect on a main girder — even if localized — can push the entire bridge's grade to 3.5–4.0 because stability is critically impaired. Conversely, widespread D:2 defects across the deck waterproofing (many areas with slight durability impact) may aggregate to a higher Zustandsnote than an isolated D:2 finding, because the extent modifier amplifies the rating. For bridges, the number of defects per inspection is typically much higher than for simpler structures — a single Main Inspection may produce 20 to 50+ individual defect records, each with its own S-V-D rating.

The responsible engineer reviews the algorithmically calculated grade and assigns a final Zustandsnote (Manuell), which may differ from the calculated value based on engineering judgment. For bridges, this manual override is particularly important when the inspector identifies systemic patterns — for example, when a combination of individually low-rated defects in bearings, joints, and drainage collectively indicates that the waterproofing system has failed, requiring a grade adjustment that the per-defect algorithm does not capture. The manual grade is the legally binding assessment that determines the bridge's maintenance classification. Bridges graded 3.0 or higher trigger mandatory repair planning, while grades of 3.5–4.0 may require immediate load restrictions, speed limits, or full closure — a decision with significant traffic network impact.

All condition grades and measures are recorded in the standards directory-referenced SIB-Bauwerke system.