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

The Hauptprüfung (H) — Main Inspection — is the most comprehensive assessment. It requires hand-close (handnah) examination of all structural components and is mandatory every six years. For retaining walls, this means the inspector must physically reach the wall face, cap, foundation zone, and drainage outlets using ladders, aerial platforms, 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, drainage blockages, and vegetation growth. While less intensive than the Main Inspection, it still requires the inspector to evaluate each component group and update defect records. The Sonderprüfung (S) — Special Inspection — is triggered by specific events such as floods, vehicle impacts, slope failures, or earthquakes. It can be ordered at any time and focuses on the damage caused by the triggering event. Additionally, DIN 1076 defines the Prüfung nach besonderen Vorschriften (V) — inspection under special regulations — for structures subject to additional requirements, and 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, 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 — ladder, aerial platform, drone, or underbridge unit — 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 retaining wall's structural load-bearing capacity. A crack in the wall face that penetrates the full section thickness receives a higher S-rating than a superficial surface crack, because it directly reduces the wall's ability to resist earth pressure. An S-rating of 4 means stability is critically impaired or lost — the wall can no longer safely perform its structural function and immediate propping, bracing, 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, or workers near the structure. For retaining walls, this axis is particularly critical for railings, cap stones, and wall sections above or adjacent to traffic lanes. A loose railing that could allow a fall scores high on V even if the wall itself is structurally sound. A V-rating of 4 means safety is not given — the structure must be closed to traffic or pedestrians immediately. Dauerhaftigkeit (D) — Durability — captures the defect's effect on the wall's long-term service life. Efflorescence, dampness penetration, 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 might receive S:2, V:0, D:3 — it slightly affects stability, poses no traffic safety risk (if it is on the rear face), 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 isolated (vereinzelt), local (bereichsweise), or widespread (flächendeckend) — 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 bridge 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.

Retaining walls are decomposed into seven component groups per ASB-ING. The Gründung (Foundation) covers the base and footing zone — often partially buried and requiring excavation or probing for a full Main Inspection. The Wand / Aufbau (Wall Structure) is the primary vertical element, which varies by wall type: reinforced concrete faces for cantilever walls, stacked stone for gravity walls, wire baskets for gabion walls, or steel profiles for sheet piles. The Kappe / Gesims (Cap/Cornice) is the top finishing element that protects the wall from water infiltration and often carries railings or barriers. The Geländer / Absturzsicherung (Railing/Fall Protection) is critical for traffic safety — any loosening, deformation, or corrosion here directly affects the V-axis rating. The Entwässerung (Drainage) includes weep holes, French drains, and collection channels that prevent hydrostatic pressure buildup behind the wall. The Fugen (Joints) are the expansion, construction, and movement joints that accommodate thermal and structural movement. Finally, the Böschung / Hinterfüllung (Slope/Backfill) covers the earth fill behind the wall and the adjacent slope stability.

The damage catalog defined by RI-EBW-PRÜF provides standardized defect types for concrete and masonry structures. Riss (Crack) is the most common finding, ranging from hairline surface cracks to full-depth structural cracks. Abplatzung (Spalling) indicates concrete cover has broken away, potentially exposing reinforcement. Kiesnest (Honeycombing) reveals poor concrete compaction during construction. Hohlstelle (Void/Delamination) is detected by hammer-tapping and indicates internal separation of concrete layers. Aussinterung (Efflorescence) — white calcium deposits on the surface — signals water migrating through the concrete and dissolving calcium hydroxide, a reliable indicator of moisture penetration. Feuchtigkeit (Dampness) and Korrosion (Corrosion) affect durability ratings directly, while Verformung (Deformation) — tilting, bulging, or bowing of the wall — is the most serious stability concern. Bewuchs (Vegetation) and Verschmutzung (Soiling) are typically lower-severity findings but can mask underlying defects if not addressed.

In the form, the inspector first selects the Bauteilgruppe (Component Group) and Schadensart (Damage Type) from dropdown fields, then locates the defect precisely using a free-text Schadensort (Location) field — for example, "Block 3, 2 m above ground level, rear face." Defect quantity is recorded with a numeric Menge (Quantity) field and an Einheit (Unit) selector for meters, square meters, cubic meters, or piece count. Photographic evidence is mandatory for every rated defect.

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 (isolated, local, or widespread) of each defect. A single S:4 defect — even if isolated — can push the entire structure's grade to 3.5–4.0 because stability is critically impaired. Conversely, widespread D:2 defects (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.

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 example, the engineer might lower the grade if they assess that a combination of individually low-rated defects creates a systemic risk that the algorithm does not capture. The manual grade is the legally binding assessment that determines the structure's maintenance classification. Structures graded 3.0 or higher trigger mandatory repair planning, while grades of 3.5–4.0 may require immediate usage restrictions or full closure.

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