216.1 Structures and slab limits

Confirm slab thickness, spans, and load paths. Deep sockets may breach PT slabs; choose shallow options where needed (244). HVM bollard anchorage must respect punching checks (333); a crash rated bollard foundation must match certificate depth (421).

Start with drawings and onsite verification. On post-tensioned (PT) decks, intrusive coring or deep sockets can cut tendons; select shallow solutions or grade-beam systems that preserve capacity. Verify that the rating-critical dependencies (embedment, concrete grade, reinforcement) match the test certificate.

For embedment depth mismatches, coordinate early with turning/service access to avoid shifting loads into weaker slabs or beams. Where PT conflicts exist, consider Shallow-Rail or frame foundations instead of deep sockets.

216.2 Ground conditions & water

Record soils, bearing, and groundwater highs/lows (423). HVM bollard pits require drainage protection (334). A crash rated bollard with shallow bases may need ground improvement (244).

Undertake basic geotechnical checks or draw on nearby site data to quantify bearing and settlement risks. High water tables demand robust drainage strategies with sumps and backflow control. In weak soils, shallow systems can still work if you spread load with grade beams, local ground improvement, or a continuous grade beam.

Log seasonal groundwater peaks and dewatering constraints, then reflect them in the programme & phasing and in dewatering plans.

216.3 Heritage/architectural controls

Height/finish and alignment constraints apply (316, 366). HVM bollard rhythm should suit frontage lines; select a crash rated bollard sleeve that maintains certification (415).

Where sightlines, heritage curtilages, or façade rules apply, preserve a consistent rhythm and frontage alignment. Use certified sleeves/finishes listed under the product family’s allowed variants so the as-tested configuration remains intact.

If taller elements are rejected, compensate with height setting discipline, near-door door protection arrays, or chicanes that maintain clear-gap rules.

216.4 Utilities corridors

Map conduits and easements (241–243). HVM bollard positions shift to preserve clearances; a crash rated bollard may switch to rails/frames when depth is blocked (332).

Combine utility searches, underground detection, and targeted trial pits to locate live services and evidence the avoidance strategy. Where deep sockets conflict with carriers or easements, pivot to certified Shallow-Rail or frame foundations, or adjust the array pattern while keeping clear-gap calculations valid.

Protect set-out by locking coordinates and benchmarks into setting-out & benchmarks before excavation begins.

216.5 Traffic & neighbors

Noise/time limits and diversion feasibility affect works (546). HVM bollard installation phases (611–629) should reduce disruption; pick a quiet crash rated bollard drive/enclosure if near residences (347).

Coordinate temporary works and traffic management with stakeholders and neighbors to maintain access and emergency routes. Where nighttime windows are mandated, sequence high-noise activities (breaking, compaction) into permitted periods and move low-noise tasks to restricted hours.

For permanent operations near sensitive receptors, prefer electromechanical drives or acoustically treated HPU enclosures, and site panels per panel siting & access.

216.6 Noise and vibration limits

Adopt low-noise equipment and hours (546). HVM bollard HPUs need lining/isolation; electromechanical drives may suit. A crash rated bollard enclosure location must meet acoustic constraints (348).

Quantify local acoustic limits and the practical path to compliance: enclosure lining, anti-vibration mounts, and buffer distances. For automatic systems, compare electromechanical drives vs hydraulics on idle and operating noise profiles, factoring ventilation hum and fan cycling.

Reflect limits in maintenance and incident response plans so after-hours callouts don’t breach permits.

216.7 Working hours & permits

Programme night/quiet modes and approvals (134). HVM bollard SAT (638) may need off-hours testing. Any crash rated bollard pour must align with curing/temperature windows (624, 627).

Map permits (road, noise, out-of-hours, hoardings) on the critical path and add authority float in the programme. In the UAE, check SIRA early for scope triggers and witness needs—see SIRA Bollards (UAE).

Plan concrete works around curing & protection and consider out-of-hours SAT to avoid daytime traffic conflicts.

216.8 Space, staging & logistics

Plan laydown, plant paths, and exclusion zones. HVM bollard components and panels need protected access (348). A crash rated bollard cage/template requires clear assembly space (621, 612).

Secure laydown close to the workface, with protected pedestrian routes and exclusion zones. Confirm crane reach, lifting paths, and safe staging for cages, formwork, and enclosures. Align deliveries with logistics, storage & handling constraints.

Build the setting-out, benchmarks, and pre-commission checklist into the daily plan so foundation accuracy and cable routing stay clean despite tight spaces.

216.9 Constraint log & mitigations

Track constraints with actions/owners (135, 719). HVM bollard design updates and crash rated bollard variant switches must pass change control (537).

Maintain a simple live log that captures the constraint, impact, chosen mitigation, and accountable owner. Link entries to the document matrix, variations & change log, and any nonconformance items.

Run design changes through change control & versioning and re-confirm rating dependencies before issue-for-use. Close the loop by updating the handover pack index.

216 Existing Site Constraints — FAQ